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Background: Photodynamic therapy (PDT) is an antitumor therapy and has traditionally been regarded as a localized therapy in itself. However, recent reports have shown that it not only exerts a direct cytotoxic effect on cancer cells but also enhances body's tumor immunity. We hypothesized that the immunological response induced by PDT could potentially enhance the efficacy of programmed death‐1 (PD‐1) / programmed death‐ligand 1 (PD‐L1) blockade. Methods: The cytotoxic effects of PDT on colon 26 cells were investigated in vitro using the WST assay. We investigated whether the antitumor effect of anti‐PD‐1 antibodies could be amplified by the addition of PDT. We performed combination therapy by randomly allocating tumor‐bearing mice to four treatment groups: control, anti‐PD‐1 antibodies, PDT, and a combination of anti‐PD‐1 antibodies and PDT. To analyze the tumor microenvironment after treatment, the tumors were resected and pathologically evaluated. Results: The viability rate of colon 26 cells decreased proportionally with the laser dose. In vivo experiments for combined PDT and anti‐PD‐1 antibody treatment, combination therapy showed an enhanced antitumor effect compared with the control. Immunohistochemical findings of the tumor microenvironment 10 days after PDT indicated that the number of CD8+ cells, the area of Iba‐1+ cells and the area expressing PD‐L1 were significantly higher in tumors treated with combination therapy than in tumors treated with anti‐PD‐1 antibody alone, PDT alone, or the control. Conclusions: PDT increased immune cell infiltration into the tumor microenvironment. The immunological response induced by PDT may enhance the efficacy of PD‐1/PD‐L1 blockade. [ABSTRACT FROM AUTHOR]

The recent discovery of copper‐mediated and mitochondrion‐dependent cuproptosis has aroused strong interest in harnessing this novel mechanism of cell death for cancer therapy. Here the design of a core‐shell nanoparticle, CuP/Er, for the co‐delivery of copper (Cu) and erastin (Er) to cancer cells for synergistic cuproptosis and ferroptosis is reported. The anti‐Warburg effect of Er sensitizes tumor cells to Cu‐mediated cuproptosis, leading to irreparable mitochondrial damage by depleting glutathione and enhancing lipid peroxidation. CuP/Er induces strong immunogenic cell death, enhances antigen presentation, and upregulates programmed death‐ligand 1 expression. Consequently, CuP/Er promotes proliferation and infiltration of T cells, and when combined with immune checkpoint blockade, effectively reinvigorates T cells to mediate the regression of murine colon adenocarcinoma and triple‐negative breast cancer and prevent tumor metastasis. This study suggests a unique opportunity to synergize cuproptosis and ferroptosis with combination therapy nanoparticles to elicit strong antitumor effects and potentiate current cancer immunotherapies. [ABSTRACT FROM AUTHOR]

Intrinsic immunosuppressive tumor microenvironment (ITM) and insufficient tumor infiltration of T cells severely impede the progress of glioblastoma (GBM) immunotherapy. In this study, it is identify that inhibiting the expression of glucose transporter 1 (GLUT1) can facilitate the prevention of lactate excretion from tumor glycolysis, which significantly alleviates the lactate‐driven ITM by reducing immunosuppressive tumor‐associated macrophages (TAMs) and regulatory T cells (Tregs). Simultaneously, the findings show that the generated inflammatory cytokine IFN‐γ during immune activation aggravates the immune escape by upregulating immune checkpoint programmed death‐ligand 1 (PD‐L1) in tumor cells and TAMs. Therefore, an injectable thermogel loaded with a GLUT1 inhibitor BAY‐876 and a PD‐1/PD‐L1 blocker BMS‐1 (Gel@B‐B) for dual‐regulation of metabolism and immunity of GBM is developed. Consequently, in situ injection of Gel@B‐B significantly delays tumor growth and prolongs the survival of the orthotopic GBM mouse model. By actively exposing tumor antigens to antigen‐presenting cells, the GBM vaccine combined with Gel@B‐B is found to significantly increase the fraction of effector T cells (Th1/CTLs) in the tumor microenvironment, thereby remarkably mitigating tumor recurrence long‐term. This study may provide a promising strategy for GBM immunotherapy. [ABSTRACT FROM AUTHOR]

Summary: Immune checkpoint blocking therapy targeting the PD‐1/PD‐L1 inhibitory signalling pathway has produced encouraging results in the treatment of a variety of cancers. Durvalumab (Imfinzi®) targeting PD‐L1 is currently used for immunotherapy of several tumour malignancies. The Fc region of this IgG1 antibody has been engineered to reduce FcγR interactions with the aim of enhancing blockade of PD‐1/PD‐L1 interactions without the depletion of PD‐L1‐expressing immune cells. Here, we used Nicotiana benthamiana to produce four variants of Durvalumab (DL): wild‐type IgG1 and its 'Fc‐effector‐silent' variant (LALAPG) carrying further modifications to increase antibody half‐life (YTE); IgG4S228P and its variant (PVA) with Fc mutations to decrease binding to FcγRI. In addition, DL variants were produced with two distinct glycosylation profiles: afucosylated and decorated with α1,6‐core fucose. Plant‐derived DL variants were compared to the therapeutic antibody regarding their ability to (i) bind to PD‐L1, (ii) block PD‐1/PD‐L1 inhibitory signalling and (iii) engage with the neonatal Fc receptor (FcRn) and various Fcγ receptors. It was found that plant‐derived DL variants bind to recombinant PD‐L1 and to PD‐L1 expressed in gastrointestinal cancer cells and are able to effectively block its interaction with PD‐1 on T cells, thereby enhancing their activation. Furthermore, we show a positive impact of Fc amino acid mutations and core fucosylation on DL's therapeutic potential. Compared to Imfinzi®, DL‐IgG1 (LALAPG) and DL‐IgG4 (PVA)S228P show lower affinity to CD32B inhibitory receptor which can be therapeutically favourable. Importantly, DL‐IgG1 (LALAPG) also shows enhanced binding to FcRn, a key determinant of serum half‐life of IgGs. [ABSTRACT FROM AUTHOR]

As an essential intracellular immune activation pathway, the cGAS‐STING pathway has attracted broad attention in cancer treatment. However, low bioavailability, nonspecificity, and adverse effects of small molecule STING agonists severely limit their therapeutic efficacy and in vivo application. In this study, a peptide‐based STING agonist is first proposed, and KLA is screened out to activate the cGAS‐STING pathway by promoting mitochondrial DNA (mtDNA) leakage. To precisely activate the cGAS‐STING pathway and block the PD‐1/PD‐L1 pathway, a multi‐stimuli activatable peptide nanodrug (MAPN) is developed for the effective delivery of KLA and PD‐L1 antagonist peptide (CVR). With rational design, MAPN achieved the site‐specific release of KLA and CVR in response to multiple endogenous stimuli, simultaneously activating the cGAS‐STING pathway and blocking PD‐1/PD‐L1 pathway, ultimately initiating robust and durable T cell anti‐tumor immunity with a tumor growth inhibition rate of 78% and extending the median survival time of B16F10 tumor‐bearing mice to 40 days. Overall, antimicrobial peptides, which can promote mtDNA leakage through damaging mitochondrial membranes, may be potential alternatives for small molecule STING agonists and giving a new insight for the design of novel STING agonists. Furthermore, MAPN presents a universal delivery platform for the effective synergy of multiple peptides. [ABSTRACT FROM AUTHOR]

Background: Though programmed cell death‐ligand 1 (PD‐L1) has been used in predicting the efficacy of immune checkpoint blockade (ICB), it is insufficient as a single biomarker. As a key effector of an intrinsically mutagenic microhomology‐mediated end joining (MMEJ) pathway, DNA polymerase theta (POLQ) was overexpressed in various malignancies, whose expression might have an influence on genomic stability, therefore altering the sensitivity to chemotherapy and immunotherapy. Methods: A total of 1304 patients with muscle‐invasive bladder cancer (MIBC) from six independent cohorts were included in this study. The Zhongshan Hospital (ZSHS) cohort (n = 134), The Cancer Genome Atlas (TCGA) cohort (n = 391), and the Neo‐cohort (n = 148) were included for the investigation of chemotherapeutic response. The IMvigor210 cohort (n = 234) and the UNC‐108 cohort (n = 89) were used for the assessment of immunotherapeutic response. In addition, the relationship between POLQ and the immune microenvironment was assessed, and GSE32894 (n = 308) was used only for the evaluation of the immune microenvironment. Results: We identified POLQhigh PD‐L1high patients could benefit more from immunotherapy and platinum‐based chemotherapy. Further analysis revealed that high POLQ expression was linked to chromosome instability and higher tumor mutational burden (TMB), which might elicit the production of neoantigens. Further, high POLQ expression was associated with an active tumor immune microenvironment with abundant infiltration of immune effector cells and molecules. Conclusions: The study demonstrated that high POLQ expression was correlated with chromosome instability and antitumor immune microenvironment in MIBC, and the combination of POLQ and PD‐L1 could be used as a superior companion biomarker for predicting the efficacy of immunotherapy. [ABSTRACT FROM AUTHOR]

Background: Mutations in one or more genes responsible for encoding subunits within the SWItch/Sucrose Non‐Fermentable (SWI/SNF) chromatin‐remodelling complexes are found in approximately 25% of cancer patients. Bromodomain containing 9 (BRD9) is a more recently identified protein coding gene, which can encode SWI/SNF chromatin‐remodelling complexes subunits. Although initial evaluations of the potential of BRD9‐based targeted therapy have been explored in the clinical application of a small number of cancer types, more detailed study of the diagnostic and prognostic potential, as well as the detailed biological mechanism of BRD9 remains unreported. Methods: We used various bioinformatics tools to generate a comprehensive, pan‐cancer analyses of BRD9 expression in multiple disease types described in The Cancer Genome Atlas (TCGA). Experimental validation was conducted in tissue microarrays and cell lines derived from lung and colon cancers. Results: Our study revealed that BRD9 exhibited elevated expression in a wide range of tumours. Analysis of survival data and DNA methylation for BRD9 indicated distinct conclusions for multiple tumours. mRNA splicing and molecular binding were involved in the functional mechanism of BRD9. BRD9 may affect cancer progression through different phosphorylation sites or N6‐methyladenosine site modifications. BRD9 could potentially serve as a novel biomarker for diagnosing different cancer types, especially could accurately forecast the prognosis of melanoma patients receiving anti‐programmed cell death 1 immunotherapy. BRD9 has the potential to serve as a therapeutic target, when pairing with etoposide in patients with melanoma. The BRD9/SMARCD1 axis exhibited promising discriminative performance in forecasting the prognosis of patients afflicted with liver hepatocellular carcinoma (LIHC) and mesothelioma. Additionally, this axis appears to potentially influence the immune response in LIHC by regulating the programmed death‐ligand 1 immune checkpoint. For experimental validation, high expression levels of BRD9 were observed in tumour tissue samples from both lung and colon cancer patients. Knocking down BRD9 led to the inhibition of lung and colon cancer development, likely via the Wnt/β‐catenin signalling pathway. Conclusions: These pan‐cancer study revealed the diagnostic and prognostic potential, along with the biological mechanism of BRD9 as a novel therapeutic target in human tumours. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) has been widely employed in tumor treatment due to its effectiveness. However, the tumor hypoxic microenvironment which is caused by abnormal vasculature severely limits the efficacy of PDT. Furthermore, the abnormal vasculature has been implicated in the failure of immunotherapy. In this study, a novel nanoparticle denoted as Combo‐NP is introduced, composed of a biodegradable NIR II fluorescent pseudo‐conjugate polymer featuring disulfide bonds within its main chain, designated as TPA‐BD, and the vascular inhibitor Lenvatinib. Combo‐NP exhibits dual functionality by not only inducing cytotoxic reactive oxygen species (ROS) to directly eliminate tumor cells but also eliciting immunogenic cell death (ICD). This ICD response, in turn, initiates a robust cascade of immune reactions, thereby augmenting the generation of cytotoxic T lymphocytes (CTLs). In addition, Combo‐NP addresses the issue of tumor hypoxia by normalizing the tumor vasculature. This normalization process enhances the efficacy of PDT while concurrently fostering increased CTLs infiltration within the tumor microenvironment. These synergistic effects synergize to potentiate the photodynamic‐immunotherapeutic properties of the nanoparticles. Furthermore, when combined with anti‐programmed death‐ligand 1 (PD‐L1), they showcase notable inhibitory effects on tumor metastasis. The findings in this study introduce an innovative nanomedicine strategy aimed at triggering systemic anti‐tumor immune responses for the treatment of Uveal melanoma. [ABSTRACT FROM AUTHOR]

Dual targeting to immune checkpoints has achieved a better therapeutic efficacy than single targeting due to synergistic extrication of tumour immunity. However, most dual targeting strategies are usually antibody dependent which facing drawbacks of antibodies, such as poor solid tumour penetration and unsatisfied affinity. To meet the challenges, we engineered a cell membrane displaying a fusion protein composed of SIRPa and PD-1 variants, the high-affinity consensus (HAC) of wild-type molecules, and with which prepared nanovesicles (NVs). Through disabling both SIRPa/CD47 and PD-1/PD-L1 signalling, HAC NVs significantly preserved the phagocytosis and antitumour effect ofmacrophages and T cells, respectively. In vivo study revealed that HAC NVs had better tumour penetration than monoclonal antibodies and higher binding affinity to CD47 and PD-L1 on tumour cells compared with the NVs expressing wild-type fusion protein. Exhilaratingly, dual-blockade of CD47 and PD-L1 with HAC NVs exhibited excellent therapeutic efficacy and biosafety. This study provided a novel biomaterial against tumoural immune escape and more importantly an attractive biomimetic technology of protein delivery formulti-targeting therapies. [ABSTRACT FROM AUTHOR]

Background: Metastatic castration‐resistant prostate cancer (mCRPC) remains fatal and incurable, despite a variety of treatments that can delay disease progression and prolong life. Immune checkpoint therapy is a promising treatment. However, emerging evidence suggests that exosomal programmed necrosis ligand 1 (PD‐L1) directly binds to PD‐1 on the surface of T cells in the drain lineage lymph nodes or neutralizes administered PD‐L1 antibodies, resulting in poor response to anti‐PD‐L1 therapy in mCRPC. Materials and Methods: Western blotting and immunofluorescence were performed to compare PD‐L1 levels in exosomes derived from different prostate cancer cells. PC3 cells were subcutaneously injected into nude mice, and then ELISA assay was used to detect human specific PD‐L1 in exosomes purified from mouse serum. The function of CD8+ T cells was detected by T cell mediated tumor cell killing assay and FACS analysis. A subcutaneous xenograft model was established using mouse prostate cancer cell RM1, exosomes with or without PD‐L1 were injected every 3 days, and then tumor size and weight were analyzed to evaluate the effect of exosomal PD‐L1. Results: Herein, we found that exosomal‐PD‐L1 was taken up by tumor cells expressing low levels of PD‐L1, thereby protecting them from T‐cell killing. Higher levels of PD‐L1 were detected in exosomes derived from the highly malignant prostate cancer PC3 and DU145 cell lines. Moreover, exosomal PD‐L1 was taken up by the PD‐L1‐low‐expressing LNCaP cell line and inhibited the killing function of CD8‐T cells on tumor cells. The growth rate of RM1‐derived subcutaneous tumors was decreased after knockdown of PD‐L1 in tumor cells, whereas the growth rate recovered following exosomal PD‐L1 tail vein injection. Furthermore, in the serum of mice with PCa subcutaneous tumors, PD‐L1 was mainly present on exosomes. Conclusion: In summary, tumor cells share PD‐L1 synergistically against T cells through exosomes. Inhibition of exosome secretion or prevention of PD‐L1 sorting into exosomes may improve the therapeutic response of prostate tumors to anti‐PD‐L1 therapy. [ABSTRACT FROM AUTHOR]

Background: Improving the potency of immune response is paramount among issues concerning immunotherapy of muscle‐invasive bladder cancer (MIBC). Methods: On the basis of immune subtypes, we investigated possible molecular mechanisms involved in tumor immune escape in MIBC. According to the 312 immune‐related genes, three MIBC immune subtypes were clustered. Results: Cluster 2 subtype is characterized by FGFR3 mutations and has a better clinical prognosis. However, the expression levels of MHC‐I and immune checkpoints genes were the lowest, indicating that this subtype is subject to immune escape and has a low response rate to immunotherapy. Bioinformatics analysis and immunofluorescence staining of clinical samples revealed that the FGFR3 is involved in the immune escape in MIBC. Besides, after FGFR3 knockout with siRNA in RT112 and UMUC14 cells, the TLR3/NF‐kB pathway was significantly activated and was accompanied by upregulation of MHC‐I and PD‐L1 gene expression. Furthermore, the use of TLR3 agonists poly(I:C) can further improve the effect. Conclusion: Together, our results suggest that FGFR3 might involve in immunosuppression by inhibition of NF‐kB pathway in BC. Considering that TLR3 agonists are currently approved for clinical treatment as immunoadjuvants, our study might provide more insights for improving the efficacy of immunotherapy in MIBC. [ABSTRACT FROM AUTHOR]

Background: Lymphocyte activation gene 3 (LAG‐3) or CD223 is a transmembrane protein that serves as an immune checkpoint which attenuates T‐cell activation. Many clinical trials of LAG‐3 inhibitors have had modest effects, but recent data indicate that the LAG‐3 antibody relatlimab, together with nivolumab (anti‐PD‐1), provided greater benefit than nivolumab alone in patients with melanoma. Methods: In this study, the RNA expression levels of 397 genes were assessed in 514 diverse cancers at a clinical‐grade laboratory (OmniSeq: https://www.omniseq.com/). Transcript abundance was normalized to internal housekeeping gene profiles and ranked (0–100 percentile) using a reference population (735 tumors; 35 histologies). Results: A total of 116 of 514 tumors (22.6%) had high LAG‐3 transcript expression (≥75 percentile rank). Cancers with the greatest proportion of high LAG‐3 transcripts were neuroendocrine (47% of patients) and uterine (42%); colorectal had among the lowest proportion of high LAG‐3 expression (15% of patients) (all p < 0.05 multivariate); 50% of melanomas were high LAG‐3 expressors. There was significant independent association between high LAG‐3 expression and high expression of other checkpoints, including programmed death‐ligand 1 (PD‐L1), PD‐1, and CTLA‐4, as well as high tumor mutational burden (TMB) ≥10 mutations/megabase, a marker for immunotherapy response (all p < 0.05 multivariate). However, within all tumor types, there was inter‐patient variability in LAG‐3 expression level. Conclusions: Prospective studies are therefore needed to determine if high levels of the LAG‐3 checkpoint are responsible for resistance to anti‐PD‐1/PD‐L1 or anti‐CTLA‐4 antibodies. Furthermore, a precision/personalized immunotherapy approach may require interrogating individual tumor immunograms to match patients to the right combination of immunotherapeutic agents for their malignancy. [ABSTRACT FROM AUTHOR]

Immune checkpoint blockade (ICB) therapies have had a tremendous impact on cancer therapy. However, most patients harbor a poorly immunogenic tumor microenvironment (TME), presenting overwhelming de novo refractoriness to ICB inhibitors. To address these challenges, combinatorial regimens that employ chemotherapies and immunostimulatory agents are urgently needed. Here, a combination chemoimmunotherapeutic nanosystem consisting of a polymeric monoconjugated gemcitabine (GEM) prodrug nanoparticle decorated with an anti‐programmed cell death‐ligand 1 (PD‐L1) antibody (αPD‐L1) on the surface and a stimulator of interferon genes (STING) agonist encapsulated inside is developed. Treatment with GEM nanoparticles upregulates PD‐L1 expression in ICB‐refractory tumors, resulting in augmented intratumor drug delivery in vivo and synergistic antitumor efficacy via activation of intratumor CD8+ T cell responses. Integration of a STING agonist into the αPD‐L1‐decorated GEM nanoparticles further improves response rates by transforming low‐immunogenic tumors into inflamed tumors. Systemically administered triple‐combination nanovesicles induce robust antitumor immunity, resulting in durable regression of established large tumors and a reduction in the metastatic burden, coincident with immunological memory against tumor rechallenge in multiple murine tumor models. These findings provide a design rationale for synchronizing STING agonists, PD‐L1 antibodies, and chemotherapeutic prodrugs to generate a chemoimmunotherapeutic effect in treating ICB‐nonresponsive tumors. [ABSTRACT FROM AUTHOR]

Immune checkpoint blockade based on antibodies has shown great clinical success in patients, but the transitory working manner leads to restricted therapeutic benefits. Herein, a genetically engineered adenovirus is developed as the vector to deliver CRISPR/Cas9 (sgCas9‐AdV) to achieve permanent PD‐L1 gene editing with efficiency up to 78.7% exemplified in Hepa 1‐6 liver cancer cells. Furthermore, the sgCas9‐AdV is loaded into hydrogel made by silk fiber (SgCas9‐AdV/Gel) for in vivo application. The silk‐gel not only promotes local retention of sgCas9‐AdV in tumor tissue, but also masks them from host immune system, thus ensuring effectively gene transduction over 9 days. Bearing these advantages, the sgCas9‐AdV/Gel inhibits Hepa 1‐6 tumor growth with 100% response rate by single‐dose injection, through efficient PD‐L1 disruption to elicit a T cell‐mediated antitumor response. In addition, the sgCas9‐AdV/Gel is also successfully extended into other refractory tumors. In CT26 colon tumor characterized by poor response to anti‐PD‐L1, sgCas9‐AdV/Gel is demonstrated to competent and superior anti‐PD‐L1 antibody to suppress tumor progression. In highly aggressive orthotopic 4T1 mouse breast tumor, such a therapeutic paradigm significantly inhibits primary tumor growth and induces a durable immune response against tumor relapse/metastasis. Thus, this study provides an attractive and universal strategy for immunotherapy. [ABSTRACT FROM AUTHOR]

Immune checkpoints are protein molecules expressed on the immune cell membrane, which regulate the immune system to kill tumor cells. As an essential immune checkpoint, overexpressed PD‐1 on tumor cells could inhibit T‐cell activation after being bonded to PD‐1. Due to this inhibitory effect, T‐cell proliferation and cytokine secretion are suppressed, leading to immune escape of tumor cells. Here, we established a high‐throughput method based on cell function screening technology to screen drugs regulating PD‐L1 expression in tumor cells at the transcriptional level. After two screening rounds, 12 compounds that enhanced PD‐L1 transcription while seven weakened were sorted out among 1018 FDA‐approved drugs. Finally, a tumor cell line was used to verify the upregulation of endogenous PD‐L1 expression for a drug named "vorinostat," a histone deacetylation inhibitor, after the two rounds of optional selection. Therefore, our research provides another perspective for using "vorinostat" in treating tumors and offers a convenient method to detect the transcriptional expression of other intracellular proteins besides PD‐L1. [ABSTRACT FROM AUTHOR]

CTLA‐4 and PD‐1 are key immune checkpoint receptors that are targeted in the treatment of cancer. A recently identified physical interaction between the respective ligands, CD80 and PD‐L1, has been shown to block PD‐L1/PD‐1 binding and to prevent PD‐L1 inhibitory functions. Since CTLA‐4 is known to capture and degrade its ligands via transendocytosis, we investigated the interplay between CD80 transendocytosis and CD80/PD‐L1 interaction. We find that transendocytosis of CD80 results in a time‐dependent recovery of PD‐L1 availability that correlates with CD80 removal. Moreover, CD80 transendocytosis is highly specific in that only CD80 is internalised, while its heterodimeric PD‐L1 partner remains on the plasma membrane of the antigen‐presenting cell (APC). CTLA‐4 interactions with CD80 do not appear to be inhibited by PD‐L1, but efficient removal of CD80 requires an intact CTLA‐4 cytoplasmic domain, distinguishing this process from more general trogocytosis and simple CTLA‐4 binding to CD80/PD‐L1 complexes. These data are consistent with CTLA‐4 acting as modulator of PD‐L1:PD‐1 interactions via control of CD80. Synopsis: The CTLA‐4 and PD‐1 immune checkpoint pathways intersect by cis interaction between their respective ligands (CD80 and PD‐L1), which interferes with PD‐L1 binding to PD‐1. Here, CTLA‐4‐mediated transendocytosis is shown to selectively deplete CD80 from the cell surface, resulting in the liberation of functional PD‐L1 that can interact with PD‐1. CD80 interacts with PD‐L1 to form cis heterodimers that prevent binding to PD‐1.CTLA‐4 transendocytosis removes CD80, but not PD‐L1, restoring the ability of PDL1 to bind PD‐1.Binding of CTLA‐4 in soluble or non‐endocytic forms to CD80‐PD‐L1 heterodimers does not effectively release free functional PD‐L1.CTLA‐4 can influence PD‐L1‐PD‐1 interaction and function by controlling CD80 expression. CTLA‐4 regulates PD‐L1‐PD‐1 interactions via transendocytosis of CD80. [ABSTRACT FROM AUTHOR]

Blockade of immune checkpoints as a strategy of cancer cells to overcome the immune response has received ample attention in cancer research recently. In particular, expression of PD‐L1 by various cancer cells has become a paradigm in this respect. Delivery of PD‐L1 to its site of action occurs either by local diffusion, or else by transport via small extracellular vesicles (sEVs, commonly referred to as exosomes). Many steps of sEVs formation, their packaging with PD‐L1 and their release into the extracellular space have been studied in detail. The likely dependence of release on Ca2+‐signaling, however, has received little attention. This is surprising, since the intracellular Ca2+‐concentration is known as a prominent regulator of many secretory processes. Here, we report on the roles of three Ca2+‐dependent proteins in regulating release of PD‐L1‐containing sEVs, as well as on the growth of tumors in mouse models. We show that sEVs release in cancer cell lines is Ca2+‐dependent and the knockdown of the gene coding the Ca2+‐channel protein ORAI1 reduces Ca2+‐signals and release of sEVs. Consequently, the T cell response is reinvigorated and tumor progression in mouse models is retarded. Furthermore, analysis of protein expression patterns in samples from human cancer tissue shows that the ORAI1 gene is significantly upregulated. Such upregulation is identified as an unfavorable prognostic factor for survival of patients with non‐small‐cell lung cancer. We show that reduced Ca2+‐signaling after knockdown of ORAI1 gene also compromises the activity of melanophilin and Synaptotagmin‐like protein 2, two proteins, which are important for correct localization of secretory organelles within cancer cells and their transport to sites of exocytosis. Thus, the Ca2+‐channel ORAI1 and Ca2+‐dependent proteins of the secretion pathway emerge as important targets for understanding and manipulating immune checkpoint blockade by PD‐L1. [ABSTRACT FROM AUTHOR]

Innate and adaptive immune systems are built‐in homeostatic functions of many multicellular organisms and protect the host against foreign pathogens and infections. Dysregulation of the molecular mechanisms of the immune system can result in autoimmune diseases. The immune system can also be harnessed and manipulated to provide targeted cancer therapies, some of them relying on the blockade of immune‐checkpoint receptors. Two prominent immune checkpoints, PD‐1/PD‐L1 and CTLA‐4/CD80, comprise receptor–ligand pairs that prevent the host immune cells from attacking host tissues. However, cancer cells upregulate the respective PD‐L1 and CD80 ligands for PD‐1 and CTLA‐4 and thereby evade the host‐immune response. Therapeutic drugs that block PD‐1/PD‐L1 and CTLA‐4/CD80 interactions re‐enable the immune system to attack cancer cells, but their prognostic biomarker remains challenging. In this review, we discuss how the use of quantitative molecular imaging can be exploited to predict the response to anti‐PD‐1/PD‐L1 therapies and to identify cancer patients who would benefit from them. [ABSTRACT FROM AUTHOR]

Metastatic intrathyroid thymic carcinoma (ITTC) is a rare cancer with no effective drugs for controlling. This case report has shown genomic and immune microenvironment profiles in metastatic ITTC and emphasized an immunosuppression via a PD‐1/PD‐L1 pathway, possibly strengthening the rationale for immune checkpoint blockade as a novel treatment. [ABSTRACT FROM AUTHOR]

The existence of inadequate ablation remains an important cause of treatment failure for loco‐regional ablation therapies. Here, using a preclinical model, it is reported that inadequate microwave ablation (iMWA) induces immunosuppressive niche predominated by myeloid cells. The gene signature of ablated tumor presented by transcriptome analyses is highly correlated with immune checkpoint blocking (ICB) resistance. Thus, an in situ scaffold with synergistic delivery of IPI549 and anti‐programmed death‐ligand 1 blocking antibody (aPDL1) for postablative cancer immunotherapy is designed and engineered, in which IPI549 capable of targeting myeloid cells could disrupt the immunosuppressive niche and subsequently improve ICB‐mediated antitumor immune response. Based on five mouse cancer models, it is demonstrated that this biomaterial system (aPDL1&IPI549@Gel) could mimic a "hot" tumor‐immunity niche to inhibit tumor progression and metastasis, and protect cured mice against tumor rechallenge. This work enables a new standard‐of‐care paradigm for the immunotherapy of myeloid cells‐mediated "cold" tumors after loco‐regional inadequate practices. [ABSTRACT FROM AUTHOR]

Despite their potent antitumor activity, clinical application of immune checkpoint inhibitors has been significantly limited by their poor response rates (<30%) in cancer patients, primarily due to immunosuppressive tumor microenvironments. As a representative immune escape mechanism, cancer‐derived exosomes have recently been demonstrated to exhaust CD8+ cytotoxic T cells. Here, it is reported that sulfisoxazole, a sulfonamide antibacterial, significantly decreases the exosomal PD‐L1 level in blood when orally administered to the tumor‐bearing mice. Consequently, sulfisoxazole effectively reinvigorates exhausted T cells, thereby eliciting robust antitumor effects in combination with anti‐PD‐1 antibody. Overall, sulfisoxazole regulates immunosuppression through the inhibition of exosomal PD‐L1, implying its potential to improve the response rate of anti‐PD‐1 antibodies. [ABSTRACT FROM AUTHOR]

Despite their potent antitumor activity, clinical application of immune checkpoint inhibitors has been significantly limited by their poor response rates (<30%) in cancer patients, primarily due to immunosuppressive tumor microenvironments. As a representative immune escape mechanism, cancer‐derived exosomes have recently been demonstrated to exhaust CD8+ cytotoxic T cells. Here, it is reported that sulfisoxazole, a sulfonamide antibacterial, significantly decreases the exosomal PD‐L1 level in blood when orally administered to the tumor‐bearing mice. Consequently, sulfisoxazole effectively reinvigorates exhausted T cells, thereby eliciting robust antitumor effects in combination with anti‐PD‐1 antibody. Overall, sulfisoxazole regulates immunosuppression through the inhibition of exosomal PD‐L1, implying its potential to improve the response rate of anti‐PD‐1 antibodies. [ABSTRACT FROM AUTHOR]

Combinations of immune checkpoint therapies show encouraging results in the treatment of many human cancers. However, the higher costs and greater side effects of such combinations compared with single‐agent immunotherapies limit their further applications. In this work, a novel smart agent, KN046@19F‐ZIF‐8, is developed to overcome these limitations. KN046 is a novel recombinant humanized PD‐L1/CTLA‐4 bispecific single‐domain antibody‐Fc fusion protein, which can bind to both PD‐L1 and CTLA‐4 effectively. ZIF‐8 is a smart delivery system, which can safely and effectively deliver KN406 to a tumor. In vitro and in vivo results demonstrate that the smart agent KN046@19F‐ZIF‐8 not only improves the immune response rate of the antibody drug in treatment of tumors but also reduces its toxic side effects, thereby achieving excellent antitumor efficacy. This study provides an engineering strategy for clinical applications of a more effective immunotherapy. [ABSTRACT FROM AUTHOR]

Programmed death ligand 1 (PD‐L1) is critical for the ability of cancer cells to evade attacks by the host immune system. However, the molecular mechanisms controlling PD‐L1 expression have not been fully understood. Here, we demonstrate that sorting nexin 6 (SNX6) is a novel regulator of PD‐L1 expression. Knockdown of SNX6 in cancer cells significantly decreases PD‐L1 protein levels. In contrast, loss of SNX6 does not reduce PD‐L1 mRNA levels. Instead, SNX6 interacts with Cullin3, an E3 ubiquitin ligase responsible for PD‐L1 ubiquitination and subsequent degradation. By binding with Cullin3, SNX6 decreases the interaction between the adaptor protein speckle‐type POZ protein and Cullin3, which in turn downregulates Cullin3‐mediated PD‐L1 ubiquitination. This research reveals a novel molecular nexus in modulating PD‐L1. [ABSTRACT FROM AUTHOR]

Objective: Neuroendocrine cervical cancer (NECC) is a rare cervical cancer with high aggressivity that causes poor prognosis even in the early stage. Given other neuroendocrine carcinomas and other types of cervical cancer have been proved to have expression of programmed cell death protein 1 ligand 1(PD‐L1) and poly ADP‐ribose polymerase‐1(PARP1), we would measure and analyze these proteins in this invasive cancer. The purpose of this study is to investigate the application value of PD‐1/PD‐L1 and PARP1 inhibitors in NECC. Methods: The NECC cases in our center with formalin‐fixed paraffin‐embedded tissue blocks were collected, and immunohistochemical (IHC) staining of PD‐L1, PARP1, Mismatch repair proteins (MMRs), and P53 was performed. Chi‐square test was used to analyze associations between various protein expressions. We analyzed the efficacy of immunotherapy in a recent patient with secondary recurrence after two courses of chemotherapy. Results: After rigorous screening, 20 cases were finally included. Three cases did not undergo surgical treatment because of their advanced stage. Twelve (60%) developed distant metastases or relapsed within five years, and most of them within two years. The positive rate of PD‐L1 and PARP1 were 70% and 75% respectively. Among all the cases, microsatellite instability (MSI) was seen in six cases (30%) and abnormal p53 expression was in 15 patients (75%). PD‐L1 was associated with PARP1 expression in the MSI subgroup. The patient treated with chemotherapy + VEGF inhibitor (VEGFi) + programmed cell death protein 1(PD‐1) inhibitor had an excellent improvement in clinical symptoms, tumor markers, and mass size. Conclusion: The IHC results of PD‐L1, PARP1, and MMRs suggested that NECC was the target of immunotargeted therapy. Our case confirmed that immune checkpoint therapy was effective in patients with PD‐L1 positive and MMRs loss. Considering the clinical practicability, more cases should be collected, and effective biomarkers still need to be further searched. [ABSTRACT FROM AUTHOR]

Beta cell replacement therapy varies depending on the cell sources: allogeneic, or xenogeneic islet; beta-like cells derived from ESCs or iPSCs. There have been many efforts to cure type 1 diabetes, including immunotherapy, artificial pancreas, and beta cell replacement therapy (Figure 1). Beta cell replacement therapy varies depending on the cell sources: allogeneic, or xenogeneic islet; beta-like cells derived from ESCs or iPSCs. [Extracted from the article]

Background: The significance of epithelial‐mesenchymal transition (EMT) and immune checkpoint proteins in thymic carcinoma remains unknown. We examined the clinical significance of EMT, tumor‐infiltrating lymphocytes expressing the immune checkpoint protein, programmed cell death 1 (PD‐1 + TILs), and the expression of PD‐1 ligand 1 (PD‐L1) in thymic carcinoma (TC). We also investigated the relationships between these immune checkpoint proteins and the EMT status and examined the impact of induction chemotherapy on patients with tumors that express these proteins. Methods: The relationship between PD‐1 + TILs/PD‐L1 and clinicopathological findings including EMT was investigated by immunohistochemistry (IHC) of surgically resected samples from 43 patients with TC. In 15 patients receiving induction therapy (IT), those factors were compared before and after IT. Results: With IHC, 26 cases (60.5%) were positive for PD‐L1, and 19 cases were positive for PD‐1 + TILs (44.2%). The disease‐free survival rate in patients showing EMT and who were PD‐1/PD‐L1 positive was significantly worse compared to negative cases (EMT; P = 0.0095, PD‐1; P = 0.001, PD‐L1; P = 0.0037). We found a significant relationship between PD‐L1 and EMT status (P = 0.01). In patients who received IT, PD‐L1 increased, and the change was strongly correlated with EMT status (P = 0.01). Conclusion: Epithelial‐mesenchymal transition, PD‐L1, and PD‐1 + TILs have prognostic impact, and PD‐L1 is correlated with EMT status. PD‐L1 expression after IT was significantly higher compared to before IT and was correlated with the EMT change. Thus, PD‐L1 may be upregulated during EMT, and anti‐PD‐1/PD‐L1 immunotherapy may provide reliable treatment of TC in combination with chemotherapy. We investigated the clinical significance of the immune checkpoint proteins (PD‐1/PD‐L1) and EMT of thymic cancer, and also examined the relationships between PD‐L1 expression and EMT status. [ABSTRACT FROM AUTHOR]