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Therapy-induced molecular adaptation of triple-negative breast cancer is crucial for immunotherapy response and resistance. We analyze tumor biopsies from three different time points in the randomized neoadjuvant GeparNuevo trial (NCT02685059), evaluating the combination of durvalumab with chemotherapy, for longitudinal alterations of gene expression. Durvalumab induces an activation of immune and stromal gene expression as well as a reduction of proliferation-related gene expression. Immune genes are positive prognostic factors irrespective of treatment, while proliferation genes are positive prognostic factors only in the durvalumab arm. We identify stromal-related gene expression as a contributor to immunotherapy resistance and poor therapy response. The results provide evidence from clinical trial cohorts suggesting a role for stromal reorganization in therapy resistance to immunotherapy and in the generation of an immune-suppressive microenvironment, which might be relevant for future therapy approaches targeting the tumor stroma parallel to immunotherapy, such as combinations of immunotherapy with anti-angiogenic therapy., Competing Interests: Declaration of interests C.D. reports grants from European Commission H2020, grants from German Cancer Aid Translational Oncology, grants from German Breast Group, and grants from BMBF to the institution during the conduct of the study; personal fees from Novartis, personal fees from Roche, personal fees from MSD Oncology, personal fees from Daiichi Sankyo, personal fees from AstraZeneca and Molecular Health, grants from Myriad, personal fees from Merck, and other funding from Sividon Diagnostics outside the submitted work; in addition, C.D. has a patent VMScope digital pathology software with royalties paid, a patent WO2020109570A1—cancer immunotherapy pending, and a patent WO2015114146A1 and WO2010076322A1—therapy response issued. J.R. declares to be a GBG Forschungs GmbH employee. GBG Forschungs GmbH received funding for research grants from AbbVie, Amgen, AstraZeneca, BMS, Daiichi Sankyo, Gilead, Molecular Health, Novartis, Pfizer, and Roche (paid to the institution). Funding was also received (non-financial/medical writing) from Daiichi Sankyo, Gilead, Novartis, Pfizer, Roche, and Seagen (paid to the institution). GBG Forschungs GmbH has royalties in VM Scope and patents pending: EP14153692.0, EP21152186.9, and EP15702464.7. T.K. reports a patent WO2020109570A1 pending. S.R. declares to be a GBG Forschungs GmbH employee. GBG Forschungs GmbH received funding for research grants from AbbVie, Amgen, AstraZeneca, BMS, Daiichi Sankyo, Gilead, Molecular Health, Novartis, Pfizer, and Roche (paid to the institution). J.H. reports research funding from Lilly; honoraria from Lilly, Novartis, Roche, Pfizer, AstraZeneca, Seagen, Gilead, and Daiichi; consulting and advisory relationships with Lilly, Novartis, Roche, Pfizer, AstraZeneca, Gilead, and Daiichi; travel expenses from Roche, Novartis, Daiichi, and Gilead. P.J. reports research funding and travel expenses from Gilead Sciences GmbH. C.H. reports an advisory role and speakers bureau role for AstraZeneca, Roche, Novartis, and Aristo Pharma. B.V.S. is an employee of BioNTech SE and reports a patent WO2020109570A1 pending. J.-U.B. reports consultation fees, honoraria, and reimbursement for attending symposia from AstraZeneca, Amgen, Daiichi Sankyo, Eisai, Gilead, Lilly, MSD, Novartis, Pfizer, Roche, and Seagen. M.v.M. reports personal fees, honoraria, or travel grants from Amgen, AstraZeneca, Daiichi Sankyo, Genomic Health, GSK, Lilly, Molecular Health, MSD, Mylan, Novartis, Pfizer, Pierre Fabre, Roche, and Seagen. C. Schem reports speaker activities for Roche, Pfizer, Novartis, Celgen, Novartis, Exact Sciences, MSD, AstraZeneca, Lilly, and Seagen, as well as advisory boards for Roche, Astra Zeneca, Pfizer, Novartis, MSD, Amgen, Exact Sciences, Stemline, Lilly, and Novartis. T.L. reports personal fees from Amgen, Roche, Teva, Clovis, Tesaro, MSD, Novartis, Pfizer, Lilly, GSK, Gilead, AstraZeneca, Daiichi Sankyo, Stemline, and Seagen outside of the submitted work. T.L. participates in advisory boards from Amgen, MSD, Tesaro, Roche, Pfizer, Lilly, Myriad, Esai, GSK, Gilead, Daiichi Sankyo, Roche, and AstraZeneca outside of the submitted work and T.L. received travel support from Pfizer, PharmaMar, MSD, Celgene, Roche, AstraZeneca, Gilead, Daiichi Sankyo, Stemline, and Clovis outside of the submitted work. P.S. reports grants, personal fees, and non-financial support from AbbVie, Amgen, AstraZeneca, Bristol Myers Squibb Company, MSD, Incyte, Janssen-Cilag, Novartis, Takeda, Pfizer, and Roche. V.M. received speaker honoraria from AstraZeneca, Daiichi Sankyo, Eisai, GSK, Pfizer, MSD, Medac, Novartis, Roche, Seagen, Onkowissen, high5 Oncology, Medscape, Gilead, and Pierre Fabre; consultancy honoraria from Roche, Pierre Fabre, Amgen, ClinSol, Novartis, MSD, Daiichi Sankyo, Eisai, Lilly, Sanofi, Seagen, Gilead, and Stemline; institutional research support from Novartis, Roche, Seagen, and Genentech; and travel grants from Roche, Pfizer, Daiichi Sankyo, and Gilead. L.P. has received consulting fees and honoraria for advisory board participation from Pfizer, AstraZeneca, Merck, Novartis, Bristol Myers Squibb, GlaxoSmithKline, Genentech/Roche, Personalis, Daiichi, Natera, and Exact Sciences and institutional research funding from Seagen, GlaxoSmithKline, AstraZeneca, Merck, Pfizer, and Bristol Myers Squibb. C.E.G. reports the following competing interests: Exact Sciences, Advisory Board, personal; AbbVie, Steering Committee member, institutional, co-chair of SC for BrighTNess; Daiichi Sankyo, member SC, institutional, co-chair of SC for DESTINY-Breast05; Genentech/Roche, SC member, institutional, co-chair of SC for lidERA; Genentech/Roche, coordinating PI, institutional, NSABP B-59/GeparDouze; and Genentech/Roche, SC member, institutional, co-chair of SC for KATHERINE. C.J. reports honoraria from AstraZeneca, Amgen, Daiichi Sankyo, Lilly, Roche, Pfizer, MSD Oncology, Pierre Fabre, Sanofi-Aventis, Seagen, Gilead, and Novartis and has a consulting or advisory role for Amgen, Lilly, Roche, Pfizer, Pierre Fabre, Novartis, MSD Oncology, Agendia, Seagen, Gilead, Lilly, Stemline, and Medac. V.N. declares to be a GBG Forschungs GmbH employee. GBG Forschungs GmbH received funding for research grants from AbbVie, AstraZeneca, BMS, Daiichi Sankyo, Gilead, Novartis, Pfizer, and Roche (paid to the institution). GBG Forschungs GmbH received other funding from Daiichi Sankyo, Gilead, Novartis, Pfizer, Roche, and Seagen (paid to the institution). GBG Forschungs GmbH has the following royalties/patents: EP14153692.0, EP21152186.9, EP15702464.7, EP19808852.8, and VM Scope GmbH. M.U. reports honoraria from AstraZeneca, Amgen, Daiichi Sankyo, Lilly, Roche, Pfizer, MSD Oncology, Pierre Fabre, Sanofi-Aventis, Myriad, Seagen, Gilead, and Novartis; has a consulting or advisory role for Amgen, Lilly, Roche, Pfizer, Pierre Fabre, Novartis, MSD Oncology, Agendia, Seagen, Gilead, Lily, Stemline, Genzyme, and Medac; and all honoraria and fees are paid to the employer/institution. S.L. reports grants and other funding from AbbVie; other funding from Amgen; grants and other funding from AstraZeneca; other funding from BMS; grants and other funding from Celgene; grants, non-financial support, and other funding from Daiichi Sankyo; other funding from EirGenix; other funding from Eisai Europe Ltd; other funding from GSK; grants, non-financial support, and other funding from Immunomedics/Gilead; other funding from Lilly; other funding from Merck; grants from Molecular Health; grants, non-financial support, and other funding from Novartis; grants, non-financial support, and other funding from Pfizer; other funding from Pierre Fabre; other funding from Relay Therapeutics; grants, non-financial support, and other funding from Roche; other funding from Sanofi; non-financial support and other funding from Seagen; and other funding from Olema Pharmaceuticals, outside the submitted work. In addition, S.L. has a patent EP14153692.0 pending, a patent EP21152186.9 pending, a patent EP15702464.7 issued, a patent EP19808852.8 pending, and a patent Digital Ki67 Evaluator with royalties paid., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The complex heterogeneity of tumor microenvironment (TME) of triple-negative breast cancer (TNBC) presents a significant obstacle to cytotoxic immune response and successful treatment, building up one of the most hostile oncological phenotypes. Among the most abundant TME components, tumor-associated macrophages (TAMs) have pivotal pro-tumoral functions, involving discordant roles for the nuclear factor kappa-B (NF-κB) transcription factors and directing to higher levels of pathway complexity. In both resting macrophages and TAMs, we recently revealed the existence of the uncharacterized NF-κB p65/p52 dimer. In the present study, we demonstrated its enhanced active nuclear localization in TAMs and validated selected immune target genes as directly regulated by dimer binding on DNA sequences. We demonstrated by ChIP-qPCR that p65/p52 enrichment on HSPG2 and CSF-1 regulatory regions is strictly dependent on macrophage polarization and tumor environment. Our data provide novel mechanisms of transcriptional regulation in TAMs, orchestrated by the varied and dynamic nature of NF-κB combinations, which needs to be considered when targeting this pathway in cancer therapies. Our results offer p65/p52, together with identified regulatory regions on genes impacting macrophage behavior and tumor biology, as novel molecular targets for TNBC, aimed at modulating TAMs functions towards anti-tumoral phenotypes and thus improving cancer treatment outcomes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

In triple-negative breast cancer (TNBC), the tumor immune microenvironment (TIME) is a highly heterogeneous ecosystem that exerts indispensable roles in tumorigenesis and tumor progression. Cancer-associated fibroblasts (CAFs) and cancer-associated adipocytes (CAAs) are the main matrix components in the TIME of TNBC. CAFs mediate the edesmoplastic response, which is a major driver of the immunosuppressive microenvironment to promote tumor growth. In addition, CAAs, a type of tumor-educated adipocyte, participate in crosstalk with breast cancer and are capable of secreting various cytokines, adipokines and chemokines, especially C-C Motif Chemokine Ligand 2 (CCL2), resulting in changes of cancer cell phenotype and function. Therefore, how to treat tumors by regulating the CAFs and the secretion of CCL2 by CAAs in TIME is investigated here. Our research group previously found that rhein (Rhe) has been identified as effective against CAFs, while hesperidin (Hes) could effectively diminish CCL2 secretion by CAAs. Inspired by the above, we developed unique PLGA-based nanoparticles loaded with Rhe and Hes (RH-NP) using the emulsion solvent diffusion method. The RH-NP particles have an average size of 114.1 ± 0.98 nm. RH-NP effectively reduces CAFs and inhibits CCL2 secretion by CAAs, promoting increased infiltration of cytotoxic T cells and reducing immunosuppressive cell presence within tumors. This innovative, safe, low-toxic, and highly effective anti-tumor strategy could be prospective in TNBC treatment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Triple-negative breast cancer (TNBC) is a highly aggressive and heterogeneous disease that often relapses following treatment with standard radiotherapies and cytotoxic chemotherapies. Combination therapies have potential for treating refractory metastatic TNBC. In this study, we aimed to develop an antibody-drug conjugate with dual payloads (DualADC) as a chemoimmunotherapy for TNBC. The overexpression of an immune checkpoint transmembrane CD276 (also known as B7-H3) was associated with angiogenesis, metastasis, and immune tolerance in more than 60% of patients with TNBC. Development of a mAb capable of targeting the extracellular domain of surface CD276 enabled delivery of payloads to tumors, and a platform was established for concurrent conjugation of a traditional cytotoxic payload and an immunoregulating Toll-like receptor 7/8 agonist to the CD276 mAb. The DualADC effectively killed multiple TNBC subtypes, significantly enhanced immune functions in the tumor microenvironment, and reduced tumor burden by up to 90% to 100% in animal studies. Single-cell RNA sequencing, multiplex cytokine analysis, and histology elucidated the impact of treatment on tumor cells and the immune landscape. This study suggests that the developed DualADC could represent a promising targeted chemoimmunotherapy for TNBC. Significance: An anti-CD276 monoclonal antibody conjugated with both a cytotoxic drug and an immune boosting reagent effectively targets triple-negative breast cancer by inducing tumor cell death and stimulating immune cell infiltration., (©2024 The Authors; Published by the American Association for Cancer Research.)

Background: Neoantigen vaccines can induce or enhance highly specific antitumor immune responses with minimal risk of autoimmunity. We have developed a neoantigen DNA vaccine platform capable of efficiently presenting both HLA class I and II epitopes and performed a phase 1 clinical trial in triple-negative breast cancer patients with persistent disease on surgical pathology following neoadjuvant chemotherapy, a patient population at high risk of disease recurrence., Methods: Expressed somatic mutations were identified by tumor/normal exome sequencing and tumor RNA sequencing. The pVACtools software suite of neoantigen prediction algorithms was used to identify and prioritize cancer neoantigens and facilitate vaccine design for manufacture in an academic GMP facility. Neoantigen DNA vaccines were administered via electroporation in the adjuvant setting (i.e., following surgical removal of the primary tumor and completion of standard of care therapy). Vaccines were monitored for safety and immune responses via ELISpot, intracellular cytokine production via flow cytometry, and TCR sequencing., Results: Eighteen subjects received three doses of a neoantigen DNA vaccine encoding on average 11 neoantigens per patient (range 4-20). The vaccinations were well tolerated with relatively few adverse events. Neoantigen-specific T cell responses were induced in 14/18 patients as measured by ELISpot and flow cytometry. At a median follow-up of 36 months, recurrence-free survival was 87.5% (95% CI: 72.7-100%) in the cohort of vaccinated patients., Conclusion: Our study demonstrates neoantigen DNA vaccines are safe, feasible, and capable of inducing neoantigen-specific immune responses., Clinical Trial Registration Number: NCT02348320., Competing Interests: Declarations Ethics approval and consent to participate The clinical protocol was reviewed and approved by the Institutional Review Board (ID# 201505074) at Washington University School of Medicine. The research conformed to the principles of the Helsinki/Tokyo/Venice Declaration on experimentation in humans. Consent for publication Written consent for publication was obtained from all participating patients. Competing interests K.S., M.G., and O.G. are consultants for the Jaime Leandro Foundation. All other authors declare that they have no competing interests., (© 2024. The Author(s).)

Triple-negative breast cancer (TNBC) is highly heterogeneous, lacks accessible therapeutic targets, and features an immunosuppressive tumor microenvironment (TME). Anthracycline-based chemotherapy remains the primary treatment method for TNBC, while the current popular immune checkpoint inhibitors persistently encounter therapeutic resistance. Therefore, there is an urgent need to explore combined therapeutic strategies to remodel the TME and improve the treatment response. Considering the highly specific homing ability of tumor cell-derived vesicles and the key role of the signal transduction and activation of the transcription factor 3 (STAT3) pathway in TNBC, we propose a synergistic therapeutic strategy that integrates gene therapy, chemotherapy, and immunotherapy based on STAT3 short interfering RNA (siSTAT3) and doxorubicin (DOX)-functionalized tumor-derived extracellular vesicles (TEVs) (siSTAT3-DOX@TEV). The in vitro and in vivo results demonstrate that siSTAT3-DOX@TEV target tumor tissues precisely, downregulate STAT3 expression, and synergistically and efficiently induce immunogenic death, thereby reversing the immunosuppressive TME. Moreover, mass cytometry and immunohistochemistry reveal the local immune activation effect of siSTAT3-DOX@TEV, with a significant increase in M1 macrophages, CD4 + T cells, and CD8 + T cells in tumor tissues. These results provide strong hints for the development of TEV-based chemo-gene therapeutic agents for TNBC treatment at the clinical level.

Background: The failure of conventional therapies and the propensity for recurrence and metastasis make triple-negative breast cancer (TNBC) a formidable challenge with grim prognoses and diminished survival rates. Immunotherapy, including immune checkpoint blockade and chimeric antigen receptor (CAR)-T cell therapy, presents innovative and potentially more effective strategies for addressing TNBC. Within this context, the inducible costimulator (ICOS), a member of the CTLA4/CD28 family, plays a crucial role in regulating immune responses and T-cell differentiation by binding to its ligand ICOSL. However, the impact of the ICOS/ICOSL axis on cancer varies., Methods: In this study, immunohistochemistry was conducted to examine the expression level of ICOSL in TNBC tumor tissues. We developed ICOS-enhanced B7H3-CAR-T cells (ICOS-B7H3-CAR) using the third-generation CAR-T cell technology, which featured magnified ICOS expression and targeted the B7H3 antigen. Xenograft and metastasis models of TNBC were conducted to examine the cytotoxicity and durability of CAR-T cells in tumors. Overexpression and CRISPR/Cas9-mediated knockout (KO) techniques were employed to regulate the expression of ICOSL on TNBC cell lines., Results: Notably, we observed elevated ICOSL expression in TNBC tumor tissues, which correlated with poor survival prognosis in patients with TNBC. Compared with conventional B7H3-CAR-T cells, ICOS-B7H3-CAR-T cells significantly inhibited the tumor growth of TNBC cells both in vitro and in vivo, accompanied by increased secretion of cytokines such as interferon gamma and tumor necrosis factor alpha. Furthermore, the in vivo experiments illustrated that ICOS-B7H3-CAR-T cells exhibited prolonged antitumor activity and could effectively eradicate metastases in a TNBC metastasis model, consequently extending survival. Importantly, manipulating the expression of ICOSL on TNBC cells through overexpression or KO significantly influenced the function of ICOS-B7H3-CAR-T cells. This suggests that the level of ICOSL expression on TNBC cells is critical for enhancing the potent antitumor effects of ICOS-B7H3-CAR-T cells., Conclusion: Overall, our study highlights the potential clinical application of ICOS as a promising strategy for combating TNBC recurrence and metastasis., Competing Interests: Competing interests: No, there are no competing interests., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Prolyl-4-hydroxylase subunit alpha3 (P4HA3) is a triple helical procollagen synthesis protein. The role of P4HA3 in cancer development is not well known and lacks comprehensive analyses among human cancers. This study aimed to investigate the relationship between P4HA3 expression and anti-tumor immunity and its prognostic value in pan-cancer. P4HA3 expression was analyzed from TIMER2.0, GTEx, GEPIA2.0 and TCGA databases. Genetic and DNA methylation alterations, survival analysis and proteins co-expression analysis of P4HA3 in cBio Cancer Genomics Portal, TCGA, GSCA and TIMER2.0. The correlation between P4HA3 expression and immune infiltration was analyzed by TIDE, XCELL, MCPCOUNTER, and EPIC. We performed EdU and transwell experiments to evaluate the influence of P4HA3 on the proliferation, migration and invasion abilities of different tumors. Patients derived xenograft (PDX) and subcutaneous transplantation models were utilized to explore the correlation between P4HA3 and immunotherapy response in triple-negative breast cancer (TNBC). Among 33 types of cancers, P4HA3 had generally different expression between different tumors, further analysis showed that the expression of P4HA3 was correlated with the cells infiltration of the tumor microenvironment (TME). The expression of P4HA3 was positively with the cell proliferation markers and epithelial-mesenchymal transition (EMT) markers. Moreover, P4HA3 deficiency inhibited the proliferation, migration and invasion abilities of tumor cells, and promoted anti-tumor immunotherapy of PD-1/PD-L1 inhibitor. This pan-cancer analysis of P4HA3 provides a comprehensive understanding of its oncogenic and prognosis role in different cancers, P4HA3 abnormal expression could be a useful biomarker for predicting the effectiveness of immunotherapy in cancer patients., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Huang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Photothermal therapy (PTT) is a promising technology that can achieve the thermal ablation of tumors and induce immunogenic cell death (ICD). However, relying solely on the antitumor immune responses caused by PTT-induced ICD is insufficient to suppress tumor metastasis and recurrence effectively. Fortunately, multifunctional nanoformulation-based synergistic photothermal immunotherapy can eliminate primary and metastatic tumors and inhibit tumor recurrence for a long time. Herein, we select polydopamine (PDA) nanoparticles to serve as the carrier for our nanomedicine as well as a potent photothermal agent and modulator of macrophage polarization. PDA nanoparticles are loaded with the insoluble immune adjuvant Imiquimod (R837) to construct PDA(R837) nanoformulations. These straightforward yet highly effective nanoformulations demonstrate excellent performance, allowing for successful triple-negative breast cancer (TNBC) treatment through synergistic photothermal immunotherapy. Moreover, experimental results showed that PDA(R837) implementation of PTT is effective in the thermal ablation of primary tumors while causing ICD and releasing R837, further promoting dendritic cell (DC) maturation and activating the systemic antitumor immune response. Furthermore, PDA(R837) nanoformulations inhibit tumor metastasis and recurrence and achieve M1 phenotype macrophage polarization, achieving long-term and excellent antitumor efficacy. Therefore, the structurally simple PDA(R837) nanoformulations provide cancer treatment and have excellent clinical translational application prospects.

Surgical resection is a primary treatment option for patients with triple-negative breast cancer (TNBC), but it is associated with a high rate of postoperative local and metastatic relapse. Although chimeric antigen receptor-engineered NK (CAR-NK) cell therapy can specifically recognize and eradicate tumor cells, its therapeutic potency toward TNBCs is markedly suppressed by the hostile tumor microenvironment, which restricts the infiltration, survival, and effector functions of CAR-NK cells inside tumor masses. In this study, HER1-overexpressing TNBC-targeted CAR-NK (HER1-CAR-NK) cells were genetically engineered with catalase to endow them with tolerance toward the high levels of oxidative stress and hypoxia inside TNBC tumors through the catalytic decomposition of hydrogen peroxide, which is a principle reactive oxygen species inside tumors, into O2. We refer to these cells as HER1-CAR-CAT-NK cells. Upon intratumoral fixation with an injectable alginate hydrogel, HER1-CAR-CAT-NK cells enabled sustained tumor hypoxia attenuation and exhibited markedly enhanced persistence and effector functions inside TNBC tumors. As a result, locoregional HER1-CAR-CAT-NK cell therapy not only inhibited the growth of local primary residual tumors but also elicited systemic antitumor activity to suppress the growth of distant tumors. This study highlights that genetic engineering of HER1-CAR-NK cells with catalase is a promising strategy to suppress the postoperative local and distant relapse of TNBC tumors., (©2024 American Association for Cancer Research.)

Background/aim: Macrophage-mediated cancer immune evasion is modulated by the balance between "the cluster of differentiation 47 (CD47), an anti-phagocytic signal" and "calreticulin (CALR), a pro-phagocytic signal". CD47 is highly expressed in various types of cancer. However, the expression profiles of CD47 and CALR in breast cancer, especially in different hormone receptor subtypes, and the effects of CD47 blockade in macrophage-mediated therapy are not well understood., Materials and Methods: The expression levels of CD47 and CALR were investigated in breast cancer and adjacent normal tissues using immunohistochemistry. To study the effects of CD47 blockade therapy, CD47 and CALR expression in breast cancer cell lines were determined. In vitro macrophage-mediated phagocytosis of breast cancer upon treatment with a monoclonal CD47 antibody (B6H12) were performed., Results: CD47 and CALR were overexpressed in breast cancer tissues and their up-regulation was associated with hormone receptor subtypes. Patients with Luminal A breast cancer had higher levels of CD47, while patients with triple-negative breast cancer (TNBC) had higher levels of CALR. The levels of CD47 and CALR were also elevated in breast cancer cell lines of Luminal A (MCF-7) and TNBC (MDA-MB-231) subtypes. Interestingly, the expression ratio of surface CD47/CALR was significantly higher in MCF-7. Moreover, in vitro phagocytosis assays revealed that blockage of CD47 enhanced macrophage-mediated activity in both cancer cells with dramatically higher degrees of phagocytosis in MCF-7., Conclusion: The expression profiles of CD47 and CALR in breast cancer subtypes and the benefit of CD47 blocking-based immunotherapy are herein provided., (Copyright © 2024 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background/aim: Triple-negative breast cancer (TNBC) is the most heterogeneous breast cancer subtype, posing numerous challenges in clinical decision-making. Biomarkers are essential to personalize management of TNBC patients. While tumor infiltrating lymphocytes (TILs) are validated prognostic biomarkers, the requirement for tumor biopsy limits their routine use. Therefore, more accessible and reliable quantitative biomarkers are needed. Given the significant role of systemic inflammatory response in tumor onset and progression, assessing inflammatory cells via liquid biopsies emerges as a promising alternative., Patients and Methods: The PERCEPTION study, conducted at Centre Jean Perrin in France, aims to determine the correlation between TILs and peripheral blood components at diagnosis. An interim analysis was conducted after enrolling 50% of the estimated population, to evaluate study feasibility and preliminary correlations between blood cell counts and TILs., Results: Sixty-one patients were enrolled over 4.5 years, demonstrating a good inclusion rate with minimal missing data. Preliminary results for 36 analyzable patients showed no correlation between the neutrophil-to-lymphocyte ratio (NLR) and TILs (r s =-0.19, 95%CI=-0.49-0.16, p=0.3). However, a moderate, positive, statistically significant correlation was found between NLR and the CD8/FoxP3 TILs ratio (r s =0.36, 95%CI=0.03-0.64, p=0.043). The probabilistic index of 0.7 (p=0.06) between NLR-high and NLR-low groups for this ratio supports the correlation., Conclusion: The interim analysis of the PERCEPTION study confirms the feasibility of correlating blood cell counts with TILs in TNBC. Although no significant correlation was observed between NLR and TILs, the moderate positive correlation between the CD8/FoxP3 ratio and TILs suggests a potential link between systemic inflammation and local immune response. These findings underscore the potential of blood-based markers as non-invasive surrogates for TILs, encouraging further research to enhance prognosis and guide treatment strategies in TNBC., (Copyright © 2024 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Aberrant Notch, which is a defining feature of triple-negative breast cancer (TNBC) cells, regulates intercellular communication in the tumor immune microenvironment (TIME). This includes tumor-associated macrophage (TAM) recruitment through Notch-dependent cytokine secretion, contributing to an immunosuppressive TIME. Despite the low response rate of TNBC to immune checkpoint blockade (ICB), here, we report that inhibition of Notch-driven cytokine-mediated programs reduces TAMs and induces responsiveness to sequentially delivered ICB. This is characterized by the emergence of GrB + cytotoxic T lymphocytes (CTLs) in the primary tumor. A more impressive effect of sequential treatment is observed in the lung where TAM depletion and increased CTLs are accompanied by near-complete abolition of metastases. This is due to (i) therapeutic reduction in Notch-dependent, prometastatic circulating factors released by the primary tumor, and (ii) elevated PD ligand 1 (PD-L1) in lung metastases, rendering them profoundly sensitive to ICB. These findings highlight the potential of combination cytokine inhibition and ICB as an immunotherapeutic strategy in TNBC.

Treatment of triple-negative breast cancer (TNBC) poses significant challenges due to its propensity for metastasis. A key impediment lies in the suppressive immune microenvironment, which fosters tumor progression. This study introduces an approach employing a dual immune-stimulatory CD73 antibody-polymeric cytotoxic drug complex (αCD73-PLG-MMAE). This complex is designed for targeted eradication of TNBC while modulating tumor immunity through mechanisms such as immunogenic cell death (ICD) and interference with the adenosine signaling pathway. By enhancing antitumor immune responses, this strategy offers a highly effective means of treating TNBC and mitigating metastasis. The complex is synthesized by combining αCD73 with poly( L -glutamic acid) (PLG) grafted Fc binding peptides (Fc-III-4C) and Val-Cit-PAB-monomethyl auristatin E (MMAE), exploiting the affinity between αCD73 and Fc-III-4C. αCD73 selectively targets CD73 molecules on both tumor and immune suppressive cells, thereby inhibiting the adenosine pathway. Meanwhile, Val-Cit-PAB-MMAE, activated by cathepsin B, triggers selective release of MMAE, inducing ICD in tumor cells. In a 4T1 tumor model, αCD73-PLG-MMAE significantly enhances drug accumulation in tumors by 4.13-fold compared to IgG-PLG-MMAE, leading to suppression of tumor growth and metastasis. Furthermore, it synergistically augments the antitumor effects of αPD-1, resulting in a tumor inhibition rate of 92 % as compared to 21 % with αPD-1 alone. This study thus presents a pioneering therapeutic strategy for TNBC, emphasizing the potential of targeted immunomodulation in cancer treatment. STATEMENT OF SIGNIFICANCE: Antibody-drug conjugate (ADC) therapy holds promise for treating triple-negative breast cancer (TNBC). However, the current ADC, sacituzumab govitecan, fails to overcome the crucial role of adenosine in the suppressive immune microenvironment characteristic of this "cold tumor". Here, we present a dual immune-stimulatory complex, αCD73-PLG-MMAE, which targets TNBC specifically and modulates tumor immunity through mechanisms such as immunogenic cell death (ICD) and interference with the adenosine signaling pathway. Thus, it kills tumor cells with cytotoxic drugs, comprehensively regulates immunosuppression, and restores a durable immune response. This study proposes an antibody-polymeric drug complex with immunomodulatory and immunoagonist roles, offering new insights into TNBC treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Immune checkpoint inhibition (ICI) with chemotherapy is now the standard of care for stage II-III triple-negative breast cancer; however, it is largely unknown for which patients ICI without chemotherapy could be an option and what the benefit of combination ICI could be. The adaptive BELLINI trial explored whether short combination ICI induces immune activation (primary end point, twofold increase in CD8 + T cells or IFNG), providing a rationale for neoadjuvant ICI without chemotherapy. Here, in window-of-opportunity cohorts A (4 weeks of anti-PD-1) and B (4 weeks of anti-PD-1 + anti-CTLA4), we observed immune activation in 53% (8 of 15) and 60% (9 of 15) of patients, respectively. High levels of tumor-infiltrating lymphocytes correlated with response. Single-cell RNA sequencing revealed that higher pretreatment tumor-reactive CD8 + T cells, follicular helper T cells and shorter distances between tumor and CD8 + T cells correlated with response. Higher levels of regulatory T cells after treatment were associated with nonresponse. Based on these data, we opened cohort C for patients with high levels of tumor-infiltrating lymphocytes (≥50%) who received 6 weeks of neoadjuvant anti-PD-1 + anti-CTLA4 followed by surgery (primary end point, pathological complete response). Overall, 53% (8 of 15) of patients had a major pathological response (<10% viable tumor) at resection, with 33% (5 of 15) having a pathological complete response. All cohorts met Simon's two-stage threshold for expansion to stage II. We observed grade ≥3 adverse events for 17% of patients and a high rate (57%) of immune-mediated endocrinopathies. In conclusion, neoadjuvant immunotherapy without chemotherapy demonstrates potential efficacy and warrants further investigation in patients with early triple-negative breast cancer. ClinicalTrials.gov registration: NCT03815890 ., Competing Interests: Competing interests R.M.M. reports research grants from Siemens Healhtineers, Bayer Healthcare, Screenpoint Medical, Beckton & Dickinson, PA Imaging, Lunit and Koning, and is an advisory board member for Screenpoint, Bayer, Siemens and Guerbet, all outside the scope of this work. E. Kalashnikova is an employee of Natera. G.S.S. reports research funding to the institute from Merck, Agendia, AstraZeneca, Roche and Novartis and a consulting role for Novartis, Seattle Genetics and Biovica, outside the submitted work. S.C.L. reports research funding to the institute from Roche/Genentech, AstraZeneca, BMS, Tesaro, Merck, Immunomedics, Eurocept Pharmaceuticals, Agendia and Novartis and a consulting role and travel grant from Daiichi Sankyo, outside this work. C.U.B. has received research grants from Novartis, BMS and NanoString, is a paid advisory board member for BMS, MSD, Roche, Novartis, GlaxoSmithKline, AstraZeneca, Pfizer, Lilly, GenMab and Pierre Fabre and holds ownership interest in Uniti Card, Neon Therapeutics and Forty Seven, all outside this submitted work. K.E.d.V. reports research funding from Roche and is a consultant for Macomics, outside the scope of this work. R.S. reports nonfinancial support from Merck and BMS, research support from Merck, Puma Biotechnology and Roche and personal fees from Roche, BMS and Exact Sciences for advisory boards, all outside the scope of this paper. L.F.A.W. reports funding to the institute from Genmab BV. T.N.S. is an advisor for Allogene Therapeutics, Asher Bio, Merus, Neogene Therapeutics and Scenic Biotech; is a stockholder in Allogene Therapeutics, Asher Bio, Cell Control, Celsius, Merus and Scenic Biotech; and is venture partner at Third Rock Ventures, all outside of the current work. M.K. reports research funding to the institute from BMS, Roche and AstraZeneca/MedImmune and an advisory role/speakers’ fee (all compensated to the institute) for Alderaan, BMS, Domain Therapeutics, Medscape, Roche, MSD and Daiichi Sankyo, outside the submitted work. Natera provided nonfinancial support to this study. The other authors declare no competing interests., (© 2024. The Author(s).)

Solid tumours induce systemic immunosuppression that involves myeloid and T cells. B cell-related mechanisms remain relatively understudied. Here we discover two distinct patterns of tumour-induced B cell abnormality (TiBA; TiBA-1 and TiBA-2), both associated with abnormal myelopoiesis in the bone marrow. TiBA-1 probably results from the niche competition between pre-progenitor-B cells and myeloid progenitors, leading to a global reduction in downstream B cells. TiBA-2 is characterized by systemic accumulation of a unique early B cell population, driven by interaction with excessive neutrophils. Importantly, TiBA-2-associated early B cells foster the systemic accumulation of exhaustion-like T cells. Myeloid and B cells from the peripheral blood of patients with triple-negative breast cancer recapitulate the TiBA subtypes, and the distinct TiBA profile correlates with pathologic complete responses to standard-of-care immunotherapy. This study underscores the inter-patient diversity of tumour-induced systemic changes and emphasizes the need for treatments tailored to different B and myeloid cell abnormalities., Competing Interests: Competing interests The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Purpose: We evaluated T- and B-cell receptor (TCR and BCR) repertoire diversity and 38 serum cytokines in pre- and post-treatment peripheral blood of 66 patients with triple-negative breast cancer (TNBC) who received neoadjuvant chemotherapy plus durvalumab and assessed associations with pathologic response and immune-related adverse events (irAEs) during treatment., Methods: Genomic DNA was isolated from buffy coat for TCR and BCR clonotype profiling using the Immunoseq platform and diversity was quantified with Pielou's evenness index. MILLIPLEX MAP Human Cytokine/Chemokine Magnetic Bead Panel was used to measure serum cytokine levels, which were compared between groups using moderated t-statistic with Benjamini-Hochberg correction for multiple testing., Results: TCR and BCR diversity was high (Pielou's index > 0.75) in all samples. Baseline receptor diversities and change in diversity pre- and post-treatment were not associated with pathologic response or irAE status, except for BCR diversity that was significantly lower post-treatment in patients who developed irAE (unadjusted p = 0.0321). Five cytokines increased after treatment in patients with pathologic complete response (pCR) but decreased in patients with RD, most prominently IL-8. IFNγ, IL-7, and GM-CSF levels were higher in pre-treatment than in post-treatment samples of patients who developed irAEs but were lower in those without irAEs., Conclusion: Baseline peripheral blood cytokine levels may predict irAEs in patients treated with immune checkpoint inhibitors and chemotherapy, and increased post-treatment B-cell clonal expansion might mediate irAEs., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Triple-negative breast carcinoma (TNBC) remains a formidable clinical hurdle owing to its high aggressiveness and scant therapeutic options. Nonetheless, the evolving landscape of immunotherapeutic strategies opens up promising avenues for tackling this hurdle. This review discusses the advancing immunotherapy for TNBC, accentuating personalized interventions due to tumor microenvironment (TME) diversity. Immune checkpoint inhibitors (ICIs) hold pivotal significance, both as single-agent therapies and when administered alongside cytotoxic agents. Moreover, the concurrent inhibition of multiple immune checkpoints represents a potent approach to augment the efficacy of cancer immunotherapy. Synergistic effects have been observed when ICIs are combined with targeted treatments like PARP inhibitors, anti-angiogenics, and ADCs (antibody-drug conjugates). Emerging tactics include tumor vaccines, cellular immunotherapy, and oncolytic viruses, leveraging the immune system's ability for selective malignant cell destruction. This review offers an in-depth examination of the diverse landscape of immunotherapy development for TNBC, furnishing meticulous insights into various advancements within this field. In addition, immunotherapeutic interventions offer hope for TNBC, needing further research for optimization., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Despite significant progress in combining cancer immunotherapy with chemotherapy to treat triple negative breast cancer (TNBC), challenges persist due to target depletion and tumor heterogeneity, especially in metastasis. Chemotherapy lacks precise targeting abilities, and targeted therapy is inadequate in addressing the diverse heterogeneity of tumors. To address these challenges, we introduce RGDEVD-DOX as a tumor-specific immunogenic agent, namely TPD1, which targets integrin αvβ3 and gets continuously activated by apoptosis. TPD1 facilitates the caspase-3-mediated in situ amplification that results in tumor-specific accumulation of doxorubicin. This local concentration of doxorubicin induces immunogenic cell death and promotes the recruitment of immune cells to the tumor site. Notably, the tumor-targeting capabilities of TPD1 help bypass the systemic immunotoxicity of doxorubicin. Consequently, this alters the tumor microenvironment, converting it into a 'hot' tumor that is more susceptible to immune checkpoint inhibition. We demonstrated the anti-metastatic and anti-cancer efficacy of this treatment using various xenograft and metastatic models. This study underscores the high potential of caspase-3 cleavable peptide-drug conjugates to be used in conjunction with anti-cancer immunotherapies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The influence of neoplastic cells on the tumor microenvironment is poorly understood. In this study, eight patient samples representing two immunotypes of triple-negative breast cancer (TNBC), defined by quantitative histologic criteria as T-cell desert and T-cell infiltrated (TCI), were compared via label-free quantitative protein mass spectrometry of material extracted directly from targeted regions of formalin-fixed, paraffin-embedded tissue sections. Of 2934 proteins quantitated, 439 were significantly differentially abundant, among which 361 were overabundant in TCI-TNBC. The 361-protein group included proteins involved in major histocompatibility complex-I antigen processing and presentation, viral defense, DNA damage response, and innate immune signaling. Immunohistochemical validation of selected proteins showed good positive correlation between neoplastic cell histoscores and label-free quantitation. Extension of immunohistochemical analysis to a total of 58 inositol polyphosphate 4-phosphatase type II-negative TNBC confirmed elevated levels of the DNA damage sensor interferon-γ-inducible protein 16, inflammasome adaptor apoptosis-associated speck-like protein containing a CARD (ASC), and pore-forming protein gasdermin D in TCI-TNBC neoplastic cells. By contrast, cGMP-AMP synthase inhibitor barrier to autointegration factor (BAF) was elevated in the neoplastic cells of T-cell desert TNBC. These findings demonstrate a previously unknown correlation between the degree of T-cell infiltration in inositol polyphosphate 4-phosphatase type II-negative TNBC and the levels, in cognate neoplastic cells, of proteins that modulate innate immune signaling in response to DNA damage., Competing Interests: Disclosure Statement None declared., (Copyright © 2024 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

An ideal tumor treatment strategy involves therapeutic approaches that can enhance the immunogenicity of the tumor microenvironment while simultaneously eliminating the primary tumor. A cholic acid-modified iridium(III) (Ir3) photosensitizer, targeted to the endoplasmic reticulum (ER), has been reported to exhibit potent type I and type II photodynamic therapeutic effects against triple-negative breast cancer (MDA-MB-231). This photosensitizer induces pyroptotic cell death mediated by gasdermin E (GSDME) through photodynamic means and enhances tumor immunotherapy. Mechanistic studies have revealed that complex Ir3 induces characteristics of damage-related molecular patterns (DAMPs) in MDA-MB-231 breast cancer cells under light conditions. These include cell-surface calreticulin (CRT) eversion, extracellular high mobility group box 1 (HMGB1) and ATP release, accompanied by ER stress and increased reactive oxygen species (ROS). Consequently, complex Ir3 promotes dendritic cell maturation and antigen presentation under light conditions, fully activates T cell-dependent immune response in vivo, and ultimately eliminates distant tumors while destroying primary tumors. In conclusion, immune regulation and targeted intervention mediated by metal complexes represent a new and promising approach to tumor therapy. This provides an effective strategy for the development of combined targeted therapy and immunotherapy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Triple negative breast cancer (TNBC) represents a particularly aggressive and clinically challenging subtype of breast cancer, characterized by its invasive nature and generally poor prognosis. Treatment options for unresectable TNBC are limited. In recent years, the advent of PD-1/PD-L1 immune checkpoint inhibitors has offered a promising new treatment option for unresectable TNBC. The role of PD-1/PD-L1 immune checkpoint inhibitors (ICIs) in unresectable TNBC management remains a subject of debate. This article aims to synthesize evidence from randomized controlled trials (RCTs) through a meta-analysis (MA) to provide a comprehensive evaluation of the efficacy and safety profile of ICIs in the treatment of unresectable TNBC., Method: We searched PubMed, Embase, Cochrane library, Web of Science, and ClinicalTrials.gov for the eligible RCTs which compared the efficacy and safety of PD-1/PD-L1 ICIs and chemotherapy alone. The outcomes analyzed included overall survival (OS), progression-free survival (PFS), objective response rate (ORR) and treatment-related adverse effects (AEs)., Results: This meta-analysis included 11 trials. Therapy with PD-L1 inhibitors was superior to chemotherapy in terms of OS in both the intention-to-treat (ITT) population and the PD-L1-positive population. (ITT: HR: = 0.90 [0.81, 0.99], P = 0.04, I 2  = 48%; PD-L1 + : HR = 0.82 [0.70, 0.95], P = 0.01, I 2  = 64%); In terms of PFS, treatment with PD-L1 inhibitors prolonged PFS in both the ITT and PD-L1-positive populations compared with chemotherapy (ITT: HR: = 0.85 [0.77, 0.93], P = 0.0006, I 2  = 46%; PD-L1 + : HR = 0.72 [0.62, 0.83], P < 0.00001, I 2  = 70%, Fig. 5); Compared with chemotherapy alone, treatment with PD-1 inhibitors prolonged OS in both the PD-L1-positive and ITT populations. (ITT: HR = 0.87 [0.78, 0.96], P = 0.007, I 2  = 71%; CPS ≥ 1: HR = 0.81 [0.71, 0.92], P = 0.001, I 2  = 39%); In terms of PFS, therapy with PD-1 inhibitors improved PFS in both the ITT population and the PD-L1-positive population compared with chemotherapy. (ITT: HR = 0.79 [0.70, 0.90], P = 0.0004, I 2  = 0%; CPS ≥ 1: HR = 0.71 [0.61, 0.83], P < 0.0001, I 2  = 0%; CPS ≥ 10: HR = 0.67 [0.53, 0.84], P = 0.0008, I 2  = 0%)., Conclusion: Both PD-1 and PD-L1 inhibitors can offer survival benefits to TNBC patients, with the primary beneficiaries being those who are PD-L1-positive. However, immunotherapy can also lead to an increase in treatment-related adverse events. Therefore, it is essential to conduct a risk assessment for each patient before starting treatment to prevent the occurrence of serious adverse reactions., Trial Registration: This systematic review study has been filed with PROSPERO (Registration number: CRD42024571775)., (© 2024. The Author(s).)

Immunotherapy research focuses on reshaping the tumor microenvironment (TME) to enhance its antitumor immune responses, with an emphasis on understanding the impact of RNA methylation in triple-negative breast cancer (TNBC) TME regulation. This study explored the influence of various RNA methyltransferases on TME cells in TNBC and their correlation with prognosis and immunotherapy response. Using non-negative matrix factorization on single-cell RNA-sequencing data, distinct TME cell clusters were identified based on the expression of 30 RNA methyltransferases. Various analyses, including pseudotime, cell communication, transcription factor regulatory network, and gene enrichment, were conducted on these clusters. The roles of RNA methyltransferase-mediated TME clusters in prognosis and immunotherapy response were determined using TNBC bulk RNA-Seq data, and the findings were validated through immunofluorescence analysis of a tissue microarray comprising 87 samples. Spatial transcriptomic analysis further revealed the distribution of TME cell clusters. Different methyltransferase-mediated cell clusters exhibited unique metabolic, immune, transcriptional, and intercellular communication patterns. Survival analysis indicated prognostic significance in specific TME cell clusters, and immunofluorescence analysis confirmed the prognostic value of m6A&#95;WTAP + CD8T + cells. In conclusion, our study illustrated the involvement of these cell subgroups in tumor growth and antitumor immunity modulation, providing insights into the enhancement of TNBC immunotherapy., (© 2024. The Author(s).)

Triple negative breast cancer (TNBC) represents a heterogeneous subtype of breast cancer characterized by an unfavorable prognosis due to its aggressive biology. Cancer-associated adipocytes (CAAs) play an active role in tumor development, invasion and metastasis, and response to treatment by secreting various cytokines. CAAs secrete CCL2 and ADPN which significantly affect the efficacy of aPD-1 in treating breast cancer. Our recent research has demonstrated that Hesperidin, a natural phenolic compound, significantly inhibits CCL2, elevates ADPN secreted by CAAs in vitro and in vivo, remodels the immune microenvironment, and potentiates the efficacy of aPD-1 in triple-negative breast cancer. We used Oil red staining, Bodipy 493/503 staining and quantitative real-time PCR to verify the formation of CAAs. ELISA was used to detect levels of CCL2, ADPN secreted by CAAs. Changes in the number of immune cells in mouse tumor tissues were detected using flow cytometry and immunofluorescence. Our data suggest that Hesperidin PLGA nanoparticles significantly reduced CCL2 and increased ADPN secreted by CAAs, which concurrently decreased the recruitment of M2 macrophages, Tregs and MDSCs while increased the infiltration of CD8 + T cells, M1 macrophages and DCs into tumor, thus significantly potentiated the efficacy of aPD-1 in vivo. This study provides a new combined strategy for the clinical treatment of triple-negative breast cancer by interfering with CCL2, ADPN secreted by CAAs to enhance the efficacy of immunotherapy., Competing Interests: Declaration of competing interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Objective: The aim of this study was to assess the prognostic significance of α-1,3-mannitrotransferase (ALG3) in triple-negative breast cancer (TNBC) and investigate its impact and potential mechanism on the efficacy of anti-PD-1 therapy., Methods: Bioinformatics analysis was used to examine the expression of ALG3 in cancer patients using UACLAN and other databases. The associations of the ALG3 gene and the clinicopathological features of breast cancer were examined with bc-GenExMiner database. Correlation between ALG3 expression and survival was further established utilizing the Kaplan-Meier Plotter database. Immunohistochemistry (IHC) was used to analyze the expression of ALG3 in cohort of breast cancer patients from Hubei cancer hospital to confirmed the prognostic value of ALG3 in TNBC. The effect of ALG3 on the levels of infiltrating immune cells was also analyzed. And the mutation module within cBioPortal was utilized to visualize ALG3 mutations in BRCA. The CRISPR/Cas9 technique was used to establish ALG3 low-expression TNBC cell lines. Influence of ALG3 expression on cancer cell proliferation and chemotherapeutic responsiveness was scrutinized in vitro. Animal models were constructed to evaluate the alteration of tumor sensitivity to anti-PD-1 therapy with decreased ALG3 expression. And flow cytometry and IHC were used to investigate the tumor immune microenvironment. Association of PD-L1 Glycosylation and ALG3 expression were also investigated by western blot., Results: ALG3 expression was elevated in TNBC and was strikingly linked to unfavorable clinical features such as lymphatic node metastasis, high NPI, advanced stage and age, etc. Furthermore, high ALG3 expression was associated with shorter OS in TNBC patients. Mechanistically, ALG3 expression was negatively correlated with the infiltration of CD8 + T cells, CD4 + T cells, and NK cells. ALG3-KO cells had increased sensitivity to chemotherapeutic agents. In animal models, the volume of ALG3-KO tumors was lower than the control group with immunotherapy. ALG3-KO tumors showed an increased proportion of CD8 + T cells, while a decreased proportion of regulatory T cells and M2-type macrophages. The expression level of PD-L1 protein was not affected by ALG3 level, but the glycosylation level was significantly decreased in tumor. Similarly, the glycosylation level of PD-L1 is reduced in ALG3-KO cell in vitro. Additionally, ALG3 knockout lead to reduced tolerance of tumor cells to IFN-γ, thereby enhancing the efficacy of immunotherapy., Conclusion: ALG3 is a potential biomarker for poor prognosis of TNBC and may reduce the efficacy of immunotherapy by modulating the tumor microenvironment and glycosylation of PD-L1., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Triple-negative breast cancer (TNBC) is a molecular subtype of breast cancer with high aggressiveness and poor prognosis. Cancer-associated fibroblasts (CAFs) are major components of the TNBC microenvironment and play an important role in tumor progression and treatment responses. Our goal is to identify specific CAFs subpopulations contributing to TNBC development., Methods: Multiomics analyses were applied to identify the CAFs-specific genes related to immunotherapy response. The clinical significance of a CAFs subset with A-kinase anchoring protein 12 (AKAP12) positive was explored in 80 patients with TNBC through double-labeling immunofluorescence assay. Cytometry by time-of-flight and RNA sequencing were performed to elucidate the immune landscape of TNBC microenvironment and functional mechanism of AKAP12 + CAFs., Results: Multiomics analyses identified an AKAP12 + CAFs subset associated with the immunotherapy response of TNBC, and a high population of these cells is correlated with poor prognosis in patients with TNBC. Intratumoral AKAP12 + CAFs promote formation of an immunosuppressive tumor microenvironment by spatially mediating macrophage M2 polarization via interleukin-34 (IL-34)/macrophage-colony stimulating factor receptor (CSF1R) signaling in TNBC. Single-cell RNA sequencing analyses revealed that AKAP12 + fibroblasts interact with macrophages through the PI3K/AKT/IL-34 axis. In addition, pharmacological blockade of the IL-34/CSF1R signaling enhances the efficacy of anti-programmed cell death protein-1 antibody in TNBC rodent models., Conclusions: AKAP12 is mainly expressed in fibroblasts in TNBC. AKAP12 + CAFs population is negatively associated with the prognosis of patients with TNBC. AKAP12 + CAFs shape the immunosuppressive TNBC microenvironment by releasing IL-34 to promote macrophage M2 polarization. Targeting IL-34 may boost the immunotherapeutic efficacy for TNBC., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Microwave thermotherapy (MT) is a clinical local tumor ablation modality, but its applications are limited by its therapeutic efficacy and safety. Therefore, developing sensitizers to optimize the outcomes of MT is in demand in clinical practice. Herein, we engineered a special nanoframework (i.e., FdMI) based on a fucoidan-decorated zirconium metal-organic framework incorporating manganese ions and liquid physisorption for microwave tumor ablation. The monodisperse nanoframework exhibited both microwave thermal effects and microwave dynamic effects, which could effectively kill cancer cells by efficient intracellular drug delivery. Through fucoidan-mediated targeting of P-selectin in the tumor microenvironment (TME), the FdMI effectively accumulated in tumor regions, leading to significant eradication of orthotropic triple-negative breast cancer (TNBC) and aggressive Hepa1-6 liver tumors by the synergistic effects of microwave thermotherapy/dynamic therapy (MT/MDT). The eradication of primary tumors could activate systemic immune responses, which effectively inhibited distant TNBC tumors and lung metastasis of Hepa1-6 liver tumors, respectively. This work not only engineered nanoparticle sensitizers for tumor-targeted synergistic MT/MDT but also demonstrated that nanocarrier-based microwave tumor ablation could stimulate antitumor immunity to effectively inhibit distant and metastatic tumors, demonstrating the high potential for effectively managing advanced malignant tumors.

Background: Triple-negative breast cancer (TNBC) exhibits a lower survival rate in comparison to other BC subtypes. Utilizing dendritic cell (DC) vaccines as a form of immunotherapy is becoming a promising new approach to cancer treatment. However, inadequate immunogenicity of tumor antigens leads to unsatisfactory effectiveness of the DC vaccines. Exosomes are the basis for the latest improvements in tumor immunotherapy. This study examined whether TNBC-derived exosomes elicit immunogenicity on the maturation and function of monocyte-derived DCs and the impact of the exosome-treated monocyte-derived DCs (moDCs) on T cell differentiation., Methods: exosomes were isolated from MDA-MB-231 TNBC cancer cells and characterized. Monocytes were separated from peripheral blood mononuclear cells and differentiated into DCs. Then, monocyte-derived DCs were treated with TNBC-derived exosomes. Furthermore, the mRNA levels of the genes and cytokines involved in DC maturation and function were examined using qRT-PCR and ELISA assays. We also cocultured TNBC-derived exosome-treated moDCs with T cells and investigated the role of the treatment in T cell differentiation by evaluating the expression of some related genes by qRT-PCR. The concentration of the cytokines secreted from T cells cocultured with exosome-treated moDCs was quantified by the ELISA assays., Results: Our findings showed that TNBC-derived exosomes induce immunogenicity by enhancing moDCs' maturation and function. In addition, exosome-treated moDCs promote cocultured T-cell expansion by inducing TH1 differentiation through increasing cytokine production., Conclusion: TNBC-derived exosomes could improve vaccine-elicited immunotherapy by inducing an immunogenic response and enhancing the effectiveness of the DC vaccines. However, this needs to be investigated further in future studies., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Triple-negative breast cancer TNBC with higher immunogenicity and tumor-infiltrating lymphocyte (TIL) enrichment can benefit from immunotherapy relative to other breast cancer subtypes. Our work was designed to identify the TIL-related hub genes in TNBC and construct a prognostic signature for TNBC. TNBC gene expression files were obtained from the TCGA database. CIBERSORT algorithm and random forest risk model were used for immune infiltration group division. The TIL-related differentially expressed genes (DEGs) were then selected and subject to GO, KEGG analyses and GSEA. Next, Lasso cox regression analyses were adopted for constructing a prognostic risk model, followed by evaluation using time-dependent ROC curves. The copy number variation between the two risk groups was also analyzed, and major genomic mutation types were identified. Additionally, the nomogram was constructed with calibration curve for clinical prognosis analysis. Our results showed that totally 113 TNBC samples were allocated into the high or low-immune risk groups. We identified 243 DEGs between groups, namely TIL-related DEGs, with 128 upregulated and 115 downregulated genes. Among the TIL-related DEGs, 6 hub genes (SLITRK3, PCDHGB3, NELL2, SRRM4, ASIC2 and B4GALNT2) were screened out and constructed a prognostic risk signature, which had good performance for long-term prognosis prediction. Analysis of genomic mutation showed that the TP53, PIK3CA, TTH, etc. showed high mutation frequency in the two prognostic risk groups. Moreover, the higher risk score of the prognostic risk model predicted poor overall survival in TNBC patients, and nomogram and calibration curve confirmed the potent prediction ability of this model. To sum up, six TIL-related biomarkers (SLITRK3, PCDHGB3, NELL2, SRRM4, ASIC2 and B4GALNT2) were identified and used for the construction of the prognostic risk model, which might provide novel insight for the clinical decisions.

Triple-negative breast cancer (TNBC) is a challenging subtype of breast cancer characterized by the absence of estrogen and progesterone receptors and HER2 expression, leading to limited treatment options and a poorer prognosis. TNBC is particularly prevalent in premenopausal African-descent women and is associated with aggressive tumor behavior and higher metastatic potential. Tumor-associated macrophages (TAMs) are abundantly present within the TNBC microenvironment and play pivotal roles in promoting tumor growth, progression, and metastasis through various mechanisms, including immune suppression and enhancement of angiogenesis. This review provides an in-depth overview of TNBC, focusing on its epidemiology, its molecular characteristics, and the critical influence of TAMs. It discusses the pathological and molecular aspects that define TNBC's aggressive nature and reviews current and emerging therapeutic strategies aimed at targeting these dynamics. Special attention is given to the role of TAMs, exploring their potential as therapeutic targets due to their significant impact on tumor behavior and patient outcomes. This review aims to highlight the complexities of the TNBC landscape and to present the innovative approaches that are currently being pursued to improve therapeutic efficacy and patient survival.

Triple-negative breast cancer (TNBC) is a highly aggressive type of breast cancer that encompasses several distinct subtypes. Recent advances in immunotherapy offer a promising future for the treatment of these highly heterogeneous and readily metastatic tumors. Despite advancements, the efficacy of immunotherapy remains limited as shown by unimproved efficacy of PD-L1 biomarker and limited patient benefit. To enhance the effectiveness of TNBC immunotherapy, we conducted investigation on the microenvironment, and corresponding therapeutic interventions of TNBC and recommended further investigation into the identification of additional biomarkers that can facilitate the subtyping of TNBC for more targeted therapeutic approaches. TNBC is a highly aggressive subtype with dismal long-term survival due to the lack of opportunities for traditional endocrine and targeted therapies. Recent advances in immunotherapy have shown promise, but response rates can be limited due to the heterogeneous tumor microenvironments and developed therapy resistance, especially in metastatic cases. In this review, we will investigate the tumor microenvironment of TNBC and corresponding therapeutic interventions. We will summarize current subtyping strategies and available biomarkers for TNBC immunotherapy, with a particular emphasis on the need for further research to identify additional prognostic markers and refine tailored therapies for specific TNBC subtypes. These efforts aim to improve treatment sensitivity and ultimately enhance survival outcomes for advanced-stage TNBC patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Yang, Li, Yang and Shi.)

Tumor draining lymph nodes (TDLN) represent a key component of the tumor-immunity cycle. There are few studies describing how TDLNs impact lymphocyte infiltration into tumors. Here we directly compare tumor-free TDLNs draining "cold" and "hot" human triple negative breast cancers (TDLN Cold and TDLN Hot ). Using machine-learning-based self-correlation analysis of immune gene expression, we find unbalanced intranodal regulations within TDLN Cold . Two gene pairs (TBX21/GATA3-CXCR1) with opposite correlations suggest preferential priming of T helper 2 (Th2) cells by mature dendritic cells (DC) within TDLN Cold . This is validated by multiplex immunofluorescent staining, identifying more mature-DC-Th2 spatial clusters within TDLN Cold versus TDLN Hot . Associated with this Th2 priming preference, more IL4 producing mast cells (MC) are found within sinus regions of TDLN Cold . Downstream, Th2-associated fibrotic TME is found in paired cold tumors with increased Th2/T-helper-1-cell (Th1) ratio, upregulated fibrosis growth factors, and stromal enrichment of cancer associated fibroblasts. These findings are further confirmed in a validation cohort and public genomic data. Our results reveal a potential role of IL4 + MCs within TDLNs, associated with Th2 polarization and reduced immune infiltration into tumors., (© 2024. The Author(s).)

Background: Triple-negative breast cancer (TNBC) is a highly heterogeneous disease. The CBCSG010 trial is a prospective and multicenter phase III clinical trial confirming that adding adjuvant capecitabine significantly improved the 5-year disease-free survival (DFS) rate in patients with TNBC by 5.9%. In this study, we attempted to identify the specific population that benefited from adjuvant therapy., Methods: In this retrospective exploratory analysis, we performed RNA sequencing of tumor tissues from patients with TNBC in the CBCSG010 clinical trial. A single-sample gene set enrichment analysis algorithm and survival analysis were performed to characterize the intrinsic molecular features of the TNBC microenvironment and assess the associations between immune-related gene expression levels or immune cell counts with capecitabine treatment efficacy. Additionally, we performed immunohistochemical staining of 2 markers, PD-L1 and CD8, and hematoxylin-eosin staining of stromal tumor-infiltrating lymphocytes (sTILs) on formalin-fixed, paraffin-embedded specimens to validate findings from bioinformatics analyses., Results: We found that patients with TNBC with high immune-infiltration treated with capecitabine were more likely to have a better prognosis. We used a cutoff of ≥25 combined positive score (CPS) of PD-L1, ≥10% positive sTILs, and ≥10% positive cells of CD8 to define the "immune-hot" patients. Among immune-hot patients, Kaplan-Meier curves showed that 5-year DFS rates were 96.9% and 79.4% in the capecitabine and control groups, respectively (hazard ratio, 0.13; 95% CI, 0.03-0.52; P=.049 in favor of capecitabine). In the capecitabine group, the 5-year DFS rate was higher for immune-hot patients than for immune-cold patients (96.9% vs 76.4%; hazard ratio, 0.11; 95% CI, 0.04-0.29; P=.028)., Conclusions: Our study suggested that immune-hot patients with TNBC are more likely to benefit from adjuvant capecitabine, and that combining immunotherapy with chemotherapy may be expected to be more effective in immune-hot patients.

Patients with triple-negative breast cancer (TNBC) have a relatively poor clinical outcome. The immune checkpoint inhibitor (ICI) pembrolizumab combined with chemotherapy is the current standard of care in TNBC patients with stage II and III. Monotherapy with ICIs has not been comprehensively assessed in the neoadjuvant setting in TNBC patients, given unfavorable results in metastatic trials. ICIs, however, have been tested in the window of opportunity (WOO) before surgery or standard chemotherapy-based neoadjuvant treatment. The WOO design is well suited to assess an ICI alone or in combination with other ICIs, targeted therapy, radiotherapy or cryotherapy, and measure their pharmacodynamic and clinical effect in this treatment-naive population. Some patients show a good response to ICIs in WOO studies. Biomarkers like tumor-infiltrating lymphocytes, programmed death ligand-1, and interferon-γ signature may predict activity and may identify patients likely to benefit from ICIs. Moreover, an increase in tumor-infiltrating lymphocytes, programmed death ligand-1 expression or T cell receptor expansion following administration of ICIs in the WOO setting could potentially inform of immunotherapy benefit, which would allow tailoring further treatment. This article reviews WOO trials that assessed immunotherapy in the early-stage TNBC population, and how these results could be translated to test de-escalation strategies of neoadjuvant chemotherapy and immunotherapy without compromising a patient's prognosis., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Tumor immune microenvironment (TIME) spatial organization predicts outcome and therapy response in triple-negative breast cancer (TNBC). An immunosuppressive TIME containing elevated tumor-associated macrophages (TAM) and scarce CD8+ T cells is associated with poor outcome, but the regulatory mechanisms are poorly understood. Here we show that ETS1-driven caspase-1 expression, required for IL1β processing and TAM recruitment, is negatively regulated by estrogen receptors alpha (ERα) and a defining feature of TNBC. Elevated tumoral caspase-1 is associated with a distinct TIME characterized by increased pro-tumoral TAMs and CD8+ T cell exclusion from tumor nests. Mouse models prove the functional importance of ERα, ETS1, caspase-1 and IL1β in TIME conformation. Caspase-1 inhibition induces an immunoreactive TIME and reverses resistance to immune checkpoint blockade, identifying a therapeutically targetable mechanism that governs TNBC spatial organization., (© 2024. The Author(s).)

Background/aim: Patients with triple-negative breast cancer (TNBC) who obtain a pathological complete response (pCR) after neoadjuvant chemotherapy have an improved prognosis. Lymphocyte-predominant breast cancer is more likely to respond to neoadjuvant chemotherapy. Here, we investigated the correlation between tumor-infiltrating lymphocytes (TILs) in pre-treatment biopsy specimens from patients with TNBC in relation to response to NAC., Patients and Methods: The level of infiltration by immune cells expressing immune cell lineage surface markers (CD8, CD4, CD19, CD14, CD11c, and CD11b) in biopsy specimens from 52 patients with TNBC was examined using multispectral immunofluorescent labelling., Results: The level of CD8-positive TILs was significantly higher in patients with a pCR (p=0.045). The Cox proportional hazard model confirmed that lymph node involvement was associated with poorer disease-free survival (p=0.008). A high level of CD8-positive TILs was related to significantly prolonged disease-free survival in patients with node-positive TNBC (p=0.018)., Conclusion: Assessing infiltration by CD8-positive TILs in the primary tumor is a useful biomarker to predict pCR and improved outcome in patients with node-positive TNBC., (Copyright © 2024 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Tuning immune-cold tumor hot has largely attracted attention to improve cancer treatment, including immunotherapy and antibody-drug conjugates (ADCs). Utilizing multiomic analyses and experimental validation, this work identifies a pivotal role for the USP10/B7-H4 proteolytic axis in mediating the interplay between tumor immune responses and ADC efficacy, particularly for sacituzumab govitecan (SG) in treating triple negative breast cancers (TNBCs). Mechanistically, the inhibition of autocrine motility factor receptor (AMFR)-mediated ubiquitylation of B7-H4 by the deubiquitinase USP10 leads to the stabilization of B7-H4, which suppresses tumor immune activity and reduces SG treatment effectiveness. Pharmacological inhibition of USP10 promotes the degradation of B7-H4, enhancing tumor immunogenicity and consequently improving the tumor-killing efficacy of SG. In preclinical TNBC models, suppression of USP10/B7-H4 proteolytic axis is effective in increasing SG killing efficacy and reducing tumor growth, especially for the tumors with the USP10 high /B7-H7 high signature. Collectively, these findings uncover a novel strategy for targeting the immunosuppressive molecule B7-H4 for cancer therapy., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Breast cancer (BC) is classified into four major histological subtypes, namely luminal A, luminal B, HER2, and basal-like, and its treatment is based on these subtypes. The use of immune checkpoint inhibitors against BC depends on the expression of PD-1/PD-L1. Another tumor immune system-the cGAS-STING pathway-is a potential target for cancer immunotherapy. However, the status of the cGAS-STING pathway in BC has not been fully established. Therefore, we investigated the expression status of the cGAS-STING pathway and immune-related proteins in BC. We classified 111 BCs into six groups-29 hormone receptor-positive carcinomas, 12 HER2+ carcinomas (HER2), 8 luminal-HER2 carcinomas, 26 triple-negative breast carcinomas (TNBCs), 21 lobular carcinomas (LC), and 15 carcinomas with apocrine differentiation (CAD)-and investigated the relationship between BC and tumor immunity via the cGAS-STING pathway using histopathological and immunohistochemical methods. Expression of cGAS was high in CADs (100%) and low in TNBCs (35%); STING-positive lymphocytes were high in TNBC (85%, P = 0.0054). Expression of pSTAT3 was significantly high in patients with TNBC (≥10%, 88%). The proportion of PD-L1-positive tumor cells was higher in TNBCs (54%) than in other BCs (30%). SRGN expression was significantly higher in the TNBC group than in the other BC groups (58%). Tumor immune responses may differ among tumor subtypes. The cGAS-STING pathway may be functional in TNBC and CAD but not in LC. Therefore, targeting the cGAS-STING pathway might be useful in BC, particularly TNBC and CAD., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Exosomes, which are nanosized extracellular vesicles, have emerged as crucial mediators of the crosstalk between tumor cells and the immune system. Intercellular adhesion molecule 1 (ICAM1) plays a crucial role in multiple immune functions as well as in the occurrence, development and metastasis of cancer. As a glycoprotein expressed on the cell membrane, ICAM1 is secreted extracellularly on exosomes and regulates the immunosuppressive microenvironment. However, the role of exosomal ICAM1 in the immune microenvironment of breast cancer bone metastases remains unclear. This study aimed to elucidated the role of exosomal ICAM1 in facilitating CD8+ T cell exhaustion and subsequent bone metastasis in triple-negative breast cancer (TNBC). We demonstrated that TNBC cells release ICAM1-enriched exosomes, and the binding of ICAM1 to its receptor is necessary for the suppressive effect of CD8 T cell proliferation and function. This pivotal engagement not only inhibits CD8+ T cell proliferation and activation but also initiates the development of an immunosuppressive microenvironment that is conducive to TNBC tumor growth and bone metastasis. Moreover, ICAM1 blockade significantly impairs the ability of tumor exosomes to bind to CD8+ T cells, thereby inhibiting their immunosuppressive effects. The present study elucidates the complex interaction between primary tumors and the immune system that is mediated by exosomes and provides a foundation for the development of novel cancer immunotherapies that target ICAM1 with the aim of mitigating TNBC bone metastasis., Competing Interests: Declaration of Competing Interest None., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The adverse effects observed in some cancer patients treated with erythropoiesis-stimulating agents such as erythropoietin (EPO) might be due to the latter's well-known immunosuppressive functions. Here, we used a mouse model of syngeneic triple-negative breast cancer to explore EPO's immunomodulatory role in a tumour setting. Our results showed that EPO treatment promotes tumour growth, exacerbates the 'immune desert', and results in a 'cold tumour'. EPO treatment changed the immune cell distribution in peripheral blood, secondary lymphoid organs, and the tumour microenvironment (TME). Our in-depth analysis showed that EPO mainly impacts CD4 T cells by accelerating their activation in the spleen and thus their subsequent exhaustion in the TME. This process is accompanied by a general elevation of CD39 expression by several immune cells (notably CD4 T cells in the tumour and spleen), which promotes an immunosuppressive TME. Lastly, we identified a highly immunosuppressive CD39 + regulatory T cell population (ICOS + , CTLA4 + , Ki67 + ) as a potential biomarker of the risk of EPO-induced tumour progression. EPO displays pleiotropic immunosuppressive functions and enhances mammary tumour progression in mice., (© 2024 The Author(s). Immunology published by John Wiley & Sons Ltd.)

Purpose of Review: Identification of biomarkers for immunotherapy treatment in triple negative breast cancer remains crucial for improving outcomes and optimising regimes, particularly in the perioperative setting. There is a need to conduct a scoping review to provide an overview of current research, explore the wider context, and highlight future research considerations in this field., Recent Findings: The most commonly assessed biomarkers are PD-L1, TILs and CD8 + cells with correlation to outcomes mainly focused on survival. There is a growing interest in evaluating genetic markers. Conclusions are currently limited by knowledge gaps around contextual factors. Important areas of focus for future research include a greater understanding of complex cellular, genetic and metabolic interactions in the perioperative tumour microenvironment, including patient-specific immune profiles. An important challenge remains elucidating the clinical significance of the immunological effects of interventions at each stage of the perioperative period, including the use of anaesthetic agents., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Triple negative breast cancer (TNBC) subtype is characterized with higher EMT/stemness properties and immune suppressive tumor microenvironment (TME). Women with advanced TNBC exhibit aggressive disease and have limited treatment options. Although immune suppressive TME is implicated in driving aggressive properties of basal/TNBC subtype and therapy resistance, effectively targeting it remains a challenge. Minnelide, a prodrug of triptolide currently being tested in clinical trials, has shown anti-tumorigenic activity in multiple malignancies via targeting super enhancers, Myc and anti-apoptotic pathways such as HSP70. Distinct super-enhancer landscape drives cancer stem cells (CSC) in TNBC subtype while inducing immune suppressive TME. We show that Minnelide selectively targets CSCs in human and murine TNBC cell lines compared to cell lines of luminal subtype by targeting Myc and HSP70. Minnelide in combination with cyclophosphamide significantly reduces the tumor growth and eliminates metastasis by reprogramming the tumor microenvironment and enhancing cytotoxic T cell infiltration in 4T1 tumor-bearing mice. Resection of residual tumors following the combination treatment leads to complete eradication of disseminated tumor cells as all mice are free of local and distant recurrences. All control mice showed recurrences within 3 weeks of post-resection while single Minnelide treatment delayed recurrence and one mouse was free of tumor. We provide evidence that Minnelide targets tumor intrinsic pathways and reprograms the immune suppressive microenvironment. Our studies also suggest that Minnelide in combination with cyclophosphamide may lead to durable responses in patients with basal/TNBC subtype warranting its clinical investigation., (© 2024. The Author(s).)

Histone lysine-specific demethylase 1 (LSD1) is frequently overexpressed in triple negative breast cancer (TNBC), which is associated with worse clinical outcome in TNBC patients. However, the underlying mechanisms by which LSD1 promotes TNBC progression remain to be identified. We recently established a genetically engineered murine model by crossing mammary gland conditional LSD1 knockout mice with Brca1-deficient mice to explore the role of LSD1 in TNBC pathogenesis. Cre-mediated Brca1 loss led to higher incidence of tumor formation in mouse mammary glands, which was hindered by concurrent depletion of LSD1, indicating a critical role of LSD1 in promoting Brca1-deficient tumors. We also demonstrated that the silencing of a tumor suppressor gene, Tissue Factor Pathway Inhibitor 2 (TFPI2), is functionally associated with LSD1-mediated TNBC progression. Mouse Brca1-deficient tumors exhibited elevated LSD1 expression and decreased TFPI2 level compared to normal mammary tissues. Analysis of TCGA database revealed that TFPI2 expression is significantly lower in aggressive ER-negative or basal-like BC. Restoration of TFPI2 through LSD1 inhibition increased H3K4me2 enrichment at the TFPI2 promoter, suppressed tumor progression, and enhanced antitumor efficacy of chemotherapeutic agent. Induction of TFPI2 by LSD1 ablation downregulates activity of matrix metalloproteinases (MMPs) that in turn increases the level of cytotoxic T lymphocyte attracting chemokines in tumor environment, leading to enhanced tumor infiltration of CD8 + T cells. Moreover, induction of TFPI2 potentiates antitumor effect of LSD1 inhibitor and immune checkpoint blockade in poorly immunogenic TNBC. Together, our study identifies previously unrecognized roles of TFPI2 in LSD1-mediated TNBC progression, therapeutic response, and immunogenic effects., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Immune evasion is not only critical for tumor initiation and progression, but also determines the efficacy of immunotherapies. Through iterative in vivo CRISPR screens with seven syngeneic tumor models, we identified core and context-dependent immune evasion pathways across cancer types. This valuable high-confidence dataset is available for the further understanding of tumor intrinsic immunomodulators, which may lead to the discovery of effective anticancer therapeutic targets. With a focus on triple-negative breast cancer (TNBC), we found that Mga knock-out significantly enhances antitumor immunity and inhibits tumor growth. Transcriptomics and single-cell RNA sequencing analyses revealed that Mga influences various immune-related pathways in the tumor microenvironment. Our findings suggest that Mga may play a role in modulating the tumor immune landscape, though the precise mechanisms require further investigation. Interestingly, we observed that low MGA expression in breast cancer patients correlates with a favorable prognosis, particularly in those with active interferon-γ signaling. These observations provide insights into tumor immune escape mechanisms and suggest that further exploration of MGA's function could potentially lead to effective therapeutic strategies in TNBC., Competing Interests: Competing interests statement:The authors declare no competing interest.

Background: Triple-negative breast cancer (TNBC), known for its aggressiveness and limited treatment options, presents a significant challenge. Adoptive cell transfer, involving the ex vivo generation of antigen-specific T cells from peripheral blood mononuclear cells (PBMCs), emerges as a promising approach. The overexpression of mesothelin (MSLN) and nucleolin (NCL) in TNBC samples underscores their potential as targets for T cell therapy. This study explored the efficacy of multi-peptide pulsing of PBMCs to generate MSLN/NCL-specific T cells targeting MSLN + /NCL + TNBC cells., Methods: TNBC patient samples were confirmed for both MSLN and NCL expression via immunohistochemistry. Synthesized MSLN and NCL peptides were combined and administered to activate PBMCs from healthy donors. The cancer-killing ability of the resultant T cells was assessed using crystal violet staining, and their subtypes and cytotoxic cytokines were characterized through flow cytometry and cytokine bead array., Results: Findings showed that 85.3% (127/149) of TNBC cases were positive for either MSLN or NCL, or both; with single positivity rates for MSLN and NCL of 14.1% and 28.9%, respectively. MSLN and NCL peptides, with high binding affinity for HLA-A*02, were combined and introduced to activated PBMCs from healthy donors. The co-pulsed PBMCs significantly induced T EM and T EMRA CD3 + /CD8 + T cells and IFN-γ production, compared to single-peptide pulsed or unpulsed conditions. Notably, MSLN/NCL-specific T cells successfully induced cell death in MSLN + /NCL + MDA-MB-231 cells, releasing key cytotoxic factors such as perforin, granzymes A and B, Fas ligand, IFN-γ, and granulysin., Conclusions: These findings serve as a proof-of-concept for using multiple immunogenic peptides as a novel therapeutic approach in TNBC patients., (© 2024. The Author(s).)

Tumor-associated neutrophils (TANs) have been shown to promote immunosuppression and tumor progression, and a high TAN frequency predicts poor prognosis in triple-negative breast cancer (TNBC). Dysregulation of CREB-binding protein (CBP)/P300 function has been observed with multiple cancer types. The bromodomain (BRD) of CBP/P300 has been shown to regulate its activity. In this study, we found that IACS-70654, a selective CBP/P300 BRD inhibitor, reduced TANs and inhibited the growth of neutrophil-enriched TNBC models. In the bone marrow, CBP/P300 BRD inhibition reduced the tumor-driven abnormal differentiation and proliferation of neutrophil progenitors. Inhibition of CBP/P300 BRD also stimulated the immune response by inducing an IFN response and MHCI expression in tumor cells and increasing tumor-infiltrated cytotoxic T cells. Moreover, IACS-70654 improved the response of a neutrophil-enriched TNBC model to docetaxel and immune checkpoint blockade. This provides a rationale for combining a CBP/P300 BRD inhibitor with standard-of-care therapies in future clinical trials for neutrophil-enriched TNBC.

Tumor-associated macrophages (TAMs) and other myelomonocytic cells are implicated in regulating responsiveness to immunotherapies, including immune checkpoint inhibitors (ICIs) targeting the PD-1/PD-L1 axis. We have developed an ex vivo high-throughput approach to discover modulators of macrophage-mediated T cell suppression, which can improve clinical outcomes of ICIs. We screened 1,430 Food and Drug Administration (FDA)-approved small-molecule drugs using a co-culture assay employing bone-marrow-derived macrophages (BMDMs) and splenic-derived T cells. This identified 57 compounds that disrupted macrophage-mediated T cell suppression. Seven compounds exerted prominent synergistic T cell expansion activity when combined with αPD-L1. These include four COX1/2 inhibitors and two myeloid cell signaling inhibitors. We demonstrate that the use of cyclooxygenase (COX)1/2 inhibitors in combination with αPD-L1 decreases tumor growth kinetics and enhances overall survival in triple-negative breast cancer (TNBC) tumor models in a CD8 + T cell-dependent manner. Altogether, we present a rationalized approach for identifying compounds that synergize with ICI to potentially enhance therapeutic outcomes for patients with solid tumors., Competing Interests: Declaration of interests S.V.M., L.M.C., D.T., S. Kumar, and A.D. are inventors on the following US Provisional patent application: Combination Therapy for Treatment of Solid Tumors, provisional filed on 04/10/2023, provisional patent application no. 63/495,246. S. Kumar received reagent support and funding from HiberCell, Inc. S. Kummar – consultant/advisory board: Boehringer Ingelheim, SpringWorks Therapeutics, Seagen, Bayer, Genome & Company, Harbour BioMed, BPGbio Therapeutics, Oxford BioTherapeutics, Mundibiopharma, Gilead, EcoR1, and Mirati; PathomIQ (co-founder), Cadila Pharmaceuticals (scientific advisor-spouse), and Arxeon (co-founder-spouse). L.M.C. has received reagent support from Cell Signaling Technologies, Syndax Pharmaceuticals, Inc., ZielBio, Inc., and HiberCell, Inc.; holds sponsored research agreements with Syndax Pharmaceuticals and HiberCell, Inc.; receives research support from the Prospect Creek Foundation, Lustgarten Foundation for Pancreatic Cancer Research, Susan G. Komen Foundation, and the National Foundation for Cancer Research; and is on the advisory board for Carisma Therapeutics, Inc., CytomX Therapeutics, Inc., Kineta, Inc., HiberCell, Inc., Cell Signaling Technologies, Inc., Alkermes, Inc., NextCure, Guardian Bio, Dispatch Biotherapeutics, AstraZeneca Partner of Choice Network (OHSU Site Leader), Genenta Sciences, Pio Therapeutics Pty Ltd., and Lustgarten Foundation for Pancreatic Cancer Research Therapeutics Working Group, Inc. S.V.M. is on the Scientific Advisory Board of Cadila Pharmaceuticals Pvt. Ltd. and is a co-founder of Arxeon, Inc., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The tumour immune microenvironment (TIME) in breast cancer is acknowledged with an increasing role in treatment response and prognosis. With a growing number of immune markers analysed, digital image analysis may facilitate broader TIME understanding, even in single-plex IHC data. To facilitate analyses of the latter an open-source image analysis pipeline, Tissue microarray MArker Quantification (TMArQ), was developed and applied to single-plex stainings for p53, CD3, CD4, CD8, CD20, CD68, FOXP3, and PD-L1 (SP142 antibody) in a 218-patient triple negative breast cancer (TNBC) cohort with complementary pathology scorings, clinicopathological, whole genome sequencing, and RNA-sequencing data. TMArQ's cell counts for analysed immune markers were on par with results from alternative methods and consistent with both estimates from human pathology review, different quantifications and classifications derived from RNA-sequencing as well as known prognostic patterns of immune response in TNBC. The digital cell counts demonstrated how immune markers are coexpressed in the TIME when considering TNBC molecular subtypes and DNA repair deficiency, and how combination of immune status with DNA repair deficiency status can improve the prognostic stratification in chemotherapy treated patients. These results underscore the value and potential of integrating TIME and specific tumour intrinsic alterations/phenotypes for the molecular understanding of TNBC., (© 2024. The Author(s).)

Purpose: Immunotherapy (IO) in triple-negative breast cancer (TNBC) has improved survival outcomes, with promising improvements in pCR rates among early high-risk hormone receptor (HR)+/HER2- breast cancers. However, biomarkers are needed to select patients likely to benefit from IO. MHC-I and tumor-specific MHC-II (tsMHC-II) expression are candidate biomarkers for PD-(L)1 checkpoint inhibition but existing data from clinical trials included limited racial/ethnic diversity., Experimental Design: We performed multiplexed immunofluorescence assays in the Carolina Breast Cancer Study (CBCS; n = 1,628, 48% Black, 52% non-Black). Intrinsic subtype and P53 mutant-like status were identified using RNA-based multigene assays. We ranked participants based on tumoral MHC-I intensity (top 33% categorized as "MHC-Ihigh") and MHC-II+ (≥5% of tumor cells as tsMHC-II+). MHC-I/II were evaluated in association with clinicopathological features by race., Results: Black participants had higher frequency of TNBC (25% vs. 12.5%, P ≤ 0.001) and basal-like (30% vs. 14%, P ≤ 0.001) tumors overall, and higher frequency of basal-like (11% vs. 5.5%, P = 0.002) and TP53 mutant tumors (26% vs. 17%, P = 0.002) among HR+/HER2-. The frequency of tsMHC-II+ was higher in HR+/HER2- Black participants (7.9% vs. 4.9%, P = 0.04). Black participants also had higher frequency of MHC-Ihigh (38.7% vs. 28.2%, P < 0.001), which was significant among HR+/HER2- (28.2% vs. 22.1%, P = 0.02)., Conclusions: In this diverse study population, MHC-I and MHC-II tumor cell expression were more highly expressed in HR+/HER2- tumors from Black women, underscoring the importance of diverse and equitable enrollment in future IO trials., (©2024 American Association for Cancer Research.)

Semaphorin-plexin signaling plays a major role in the tumor microenvironment (TME). In particular, Semaphorin 4D (SEMA4D) has been shown to promote tumor growth and metastasis; however, the role of its high-affinity receptor Plexin-B1 (PLXNB1), which is expressed in the TME, is poorly understood. In this study, we directly targeted PLXNB1 in the TME of triple-negative murine breast carcinoma to elucidate its relevance in cancer progression. We found that primary tumor growth and metastatic dissemination were strongly reduced in PLXNB1-deficient mice, which showed longer survival. PLXNB1 loss in the TME induced a switch in the polarization of tumor-associated macrophages (TAM) toward a pro-inflammatory M1 phenotype and enhanced the infiltration of CD8+ T lymphocytes both in primary tumors and in distant metastases. Moreover, PLXNB1 deficiency promoted a shift in the Th1/Th2 balance of the T-cell population and an antitumor gene signature, with the upregulation of Icos, Perforin-1, Stat3, and Ccl5 in tumor-infiltrating lymphocytes (TILs). We thus tested the translational relevance of TME reprogramming driven by PLXNB1 inactivation for responsiveness to immunotherapy. Indeed, in the absence of PLXNB1, the efficacy of anti-PD-1 blockade was strongly enhanced, efficiently reducing tumor growth and distant metastasis. Consistent with this, pharmacological PLXNB1 blockade by systemic treatment with a specific inhibitor significantly hampered breast cancer growth and enhanced the antitumor activity of the anti-PD-1 treatment in a preclinical model. Altogether, these data indicate that PLXNB1 signaling controls the antitumor immune response in the TME and highlight this receptor as a promising immune therapeutic target for metastatic breast cancers., (©2024 The Authors; Published by the American Association for Cancer Research.)