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BRAFV600E mutations occur in 46% of melanomas and drive high levels of ERK activity and ERK-dependent proliferation. However, BRAFV600E is insufficient to drive melanoma in genetically engineered mouse models, and 82% of human benign nevi harbor BRAFV600E mutations. We found that BRAFV600E inhibited mesenchymal migration by causing feedback inhibition of RAC1 activity. ERK pathway inhibition induced RAC1 activation and restored migration and invasion. In cells with BRAFV600E, mutant RAC1 or PTEN inactivation restored RAC1 activity and cell motility. Together, these lesions occurred in 26% of melanomas with BRAFV600E mutations. Thus, although BRAFV600E activation of ERK deregulates cell proliferation, it prevents full malignant transformation by causing feedback inhibition of RAC1. Secondary mutations are, therefore, required for tumorigenesis. One mechanism underlying tumor evolution may be the selection of lesions that rescue the deleterious effects of oncogenic drivers.

Recent phase 3 clinical trial showed improved radiographic progression-free survival in PTEN-deficient prostate cancers treated with combined Akt and AR inhibition. Building on this and our previous research into PI3K and AR signaling interactions, we aimed to define the mechanisms of response and resistance to Akt inhibition. We discovered that restoration of mTOR signaling was the early dominant driver of resistance to Akt inhibition. Mechanistically, this can be achieved through molecular alterations, resulting in loss of negative regulators of mTOR. Unexpectedly, we discovered that this was dominated by restoration of mTOR signaling through the nutrient sensing arm. This can be achieved by loss of the components of the GATOR/KICSTOR complexes or through cellular processes, leading to the recycling of amino acids. The addition of an mTOR inhibitor restored sensitivity to Akt inhibition and represents a precision-based strategy to overcome resistance in the clinic.

Approximately 3.4 million patients worldwide are diagnosed each year with cancers that have pathogenic mutations in one of three RAS proto-oncogenes (KRAS, NRAS and HRAS) 1,2 . These mutations impair the GTPase activity of RAS, leading to activation of downstream signalling and proliferation 3-6 . Long-standing efforts to restore the hydrolase activity of RAS mutants have been unsuccessful, extinguishing any consideration towards a viable therapeutic strategy 7 . Here we show that tri-complex inhibitors-that is, molecular glues with the ability to recruit cyclophilin A (CYPA) to the active state of RAS-have a dual mechanism of action: not only do they prevent activated RAS from binding to its effectors, but they also stimulate GTP hydrolysis. Drug-bound CYPA complexes modulate residues in the switch II motif of RAS to coordinate the nucleophilic attack on the γ-phosphate of GTP in a mutation-specific manner. RAS mutants that were most sensitive to stimulation of GTPase activity were more susceptible to treatment than mutants in which the hydrolysis could not be enhanced, suggesting that pharmacological stimulation of hydrolysis potentiates the therapeutic effects of tri-complex inhibitors for specific RAS mutants. This study lays the foundation for developing a class of therapeutics that inhibit cancer growth by stimulating mutant GTPase activity., Competing Interests: Competing interests: P.L. is listed as an inventor on patents filed by MSKCC regarding treatment of KRAS- or BRAF-mutant cancers; reports grants to his institution from Revolution Medicines, Amgen, Mirati and Boehringer Ingelheim; and reports consulting fees or honoraria from Black Diamond Therapeutics, AmMax, OrbiMed, PAQ-Tx, Repare Therapeutics, Boehringer Ingelheim, Menarini Group and Revolution Medicines, as well as membership on the scientific advisory board of Frontier Medicines, Ikena, Biotheryx and PAQ-Tx (consulting fees and equity in each). The other authors declare no competing interests., (© 2024. The Author(s).)

Lurbinectedin is an approved second-line treatment for small-cell lung cancer (SCLC). SCLC clinical trials combining lurbinectedin with PD-L1 blockade are currently ongoing. However, the immunomodulatory effects of lurbinectedin remain largely unknown. In this study, we demonstrate that lurbinectedin treatment activates the STING pathway, which increases interferon (IFN) signaling, pro-inflammatory chemokines, and major histocompatibility complex class I (MHC-I) in SCLC models. Lurbinectedin treatment augments the anti-tumor immune response of PD-L1 blockade with significant tumor regression in first-line and maintenance settings in SCLC mouse models. In vivo, lurbinectedin treatment increases CD8 + T cells and M1 macrophages and decreases immunosuppressive M2 macrophages. STING and CD8 depletion reverses the anti-tumor response. Interestingly, our study shows that lurbinectedin treatment upregulates MHC-I/II genes and CD8 in SCLC clinical samples. We provide mechanistic insights into the effect of lurbinectedin on STING-mediated multimodal immune activation and demonstrate that lurbinectedin treatment represents a promising therapeutic strategy to potentiate the efficacy of immunotherapy in SCLC., Competing Interests: Declaration of interests T.S. has received research grants from Jazz Pharmaceuticals and Debiopharm. T.A.B. received a grant and honorarium from Bristol Meyers Squibb., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Pancreatic ductal adenocarcinoma (PDAC) is an increasingly diagnosed cancer that kills 90% of afflicted patients, with most patients receiving palliative chemotherapy. We identified neuronal pentraxin 1 (NPTX1) as a cancer-secreted protein that becomes overexpressed in human and murine PDAC cells during metastatic progression and identified adhesion molecule with Ig-like domain 2 (AMIGO2) as its receptor. Molecular, genetic, biochemical, and pharmacologic experiments revealed that secreted NPTX1 acts cell-autonomously on the AMIGO2 receptor to drive PDAC metastatic colonization of the liver-the primary site of PDAC metastasis. NPTX1-AMIGO2 signaling enhanced hypoxic growth and was critically required for hypoxia-inducible factor-1α (HIF1α) nuclear retention and function. NPTX1 is overexpressed in human PDAC tumors and upregulated in liver metastases. Therapeutic targeting of NPTX1 with a high-affinity monoclonal antibody substantially reduced PDAC liver metastatic colonization. We thus identify NPTX1-AMIGO2 as druggable critical upstream regulators of the HIF1α hypoxic response in PDAC. Significance: We identified the NPTX1-AMIGO2 axis as a regulatory mechanism upstream of HIF1α-driven hypoxia response that promotes PDAC liver metastasis. Therapeutic NPTX1 targeting outperformed a common chemotherapy regimen in inhibiting liver metastasis and suppressed primary tumor growth in preclinical models, revealing a novel therapeutic strategy targeting hypoxic response in PDAC., (©2024 American Association for Cancer Research.)

While oncogenes promote cancer cell growth, unrestrained proliferation represents a significant stressor to cellular homeostasis networks such as the DNA damage response (DDR). To enable oncogene tolerance, many cancers disable tumor suppressive DDR signaling through genetic loss of DDR pathways and downstream effectors (e.g., ATM or p53 tumor suppressor mutations). Whether and how oncogenes can help "self-tolerize" by creating analogous functional defects in physiologic DDR networks is not known. Here we focus on Ewing sarcoma, a FET fusion oncoprotein (EWSR1-FLI1) driven pediatric bone tumor, as a model for the class of FET rearranged cancers. Native FET family members are among the earliest factors recruited to DNA double-strand breaks (DSBs), though the function of both native FET proteins and FET fusion oncoproteins in DNA repair remains to be defined. We discover that the EWSR1-FLI1 fusion oncoprotein is recruited to DNA DSBs and interferes with native FET (EWSR1) protein function in activating the DNA damage sensor ATM. In multiple FET rearranged cancers, FET fusion oncoproteins induce functional ATM defects, rendering the compensatory ATR signaling axis as a collateral dependency and therapeutic target. More generally, we find that aberrant recruitment of a fusion oncoprotein to sites of DNA damage can disrupt physiologic DSB repair, revealing a mechanism for how growth-promoting oncogenes can also create functional defects within tumor suppressive DDR networks.

Trastuzumab deruxtecan (T-DXd) is a human epidermal growth factor receptor 2 (HER2)-targeting antibody drug conjugate that has remarkable activity in HER2-positive cancers. However, the degree of benefit of T-DXd is not uniform among solid tumors even with high levels of HER2. Despite high HER2 expression, the HER2/T-DXd complex may not always undergo internalization and payload release dependent on the receptor's conformation and context. We hypothesize that epidermal growth factor receptor (EGFR), a dimerization partner of HER2, can modulate HER2 trafficking through endocytic pathways and affect T-DXd uptake. We demonstrate that elevated EGFR expression levels can promote EGFR/HER2 heterodimer formation and suppress T-DXd internalization and efficacy. Knockdown of EGFR expression or pharmacologic stimulation of EGFR endocytosis with EGFR monoclonal antibodies restores T-DXd trafficking and antitumor activity in EGFR-overexpressing cancers in vivo. Our results reveal EGFR overexpression to be a potential mechanism of resistance to T-DXd, which can be overcome by combination therapy strategies targeting EGFR., Competing Interests: Declaration of interests F.M. is employed by AstraZeneca and reports stock and other ownership interests from AstraZeneca. J.Z.D. reports research funding from AstraZeneca and consulting fees from AstraZeneca, Genagon, AmMax Bio, NuProbe, and Launchpad Therapeutics. S.T. and N.G. are employed by mProbe and report research funding, stock, and other ownership interests from mProbe. S.M. reports grants from Boehringer Ingelheim and Daiichi Sankyo and serves on the scientific advisory board of Bionseek. Y.Y.J. acknowledges research funding from the National Cancer Institute, Department of Defense, Cycle for Survival, Fred’s Team, Inspirna, AstraZeneca, Arcus Biosciences, Bayer, Genentech/Roche, Bristol-Myers Squibb, Eli Lilly, Merck, and Transcenta. She has served on advisory boards and/or done consulting for AbbVie, AmerisourceBergen, AskGene Pharma, Inc., Arcus Biosciences, Astellas, AstraZeneca, Basilea Pharmaceutica, Bayer, Bristol-Myers Squibb, Daiichi Sanyko, Eli Lilly, Geneos Therapeutics, GlaxoSmithKline, Guardant Health, Inc., Imedex, Imugene, Inspirna, Lynx Health, Merck, Merck Serono, Mersana Therapeutics, Pfizer, Seagen, Silverback Therapeutics, and Zymeworks, Inc., as well as Clinical Care Options, HMP Education, Michael J. Hennessy Associates, Paradigm Medical Communications, PeerView Institute, and Research to Practice. She also holds stock options in Inspirna. W.P. acknowledges research funding from the National Cancer Institute, Break Through Cancer, Parker Institute for Cancer Immunotherapy (PICI), Society for Immunotherapy of Cancer, The Society of MSK, Merck, Astellas, Miracogen, Amgen, and Revolution Medicines. He has served on advisory boards and/or done consulting for Astellas, EXACT Therapeutics, and Innovent Biologics. He has received honoraria for continuing medical education for American Physician Institute and Integrity. R.Y. has served as an advisor for Array BioPharma/Pfizer, Mirati Therapeutics, and Amgen; received a speaker’s honorarium from Zai Lab; and has received research support to her institution from Array BioPharma/Pfizer, Boehringer Ingelheim, Boundless Bio, Mirati Therapeutics, and Daiichi Sankyo. B.T.L. reports grants and other support from Amgen and grants from the NIH during the conduct of the study; grants and personal fees from Hengrui USA; grants and other support from Genentech Roche, Lilly, AstraZeneca, and Daiichi Sankyo; nonfinancial support and other support from Resolution Bioscience; grants and nonfinancial support from MORE Health; nonfinancial support from Jiangsu Hengrui Medicine; personal fees from Boehringer Ingelheim; grants from the NIH outside the submitted work; and a patent for US62/685,057 issued, a patent for US62/514,661 issued, royalties from Karger Publishers, and licensing with Shanghai Jiao Tong University Press. S.C. has received personal consulting fees from Novartis, AstraZeneca, Nuvalent, Genesis Therapeutics, eFFECTOR Therapeutics, SAGA Diagnostics, Prelude Therapeutics, and Casdin Capital. S.C. has research funding from AstraZeneca and Daiichi Sankyo., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Neurofibromin (NF1) is a negative regulator of RAS signaling, frequently mutated in cancer. NF1-mutant melanoma is a highly malignant tumor for which targeted therapies are lacking. Here, we use biochemical and pharmacological assays on patient-derived models and isogenic cell lines to identify potential pharmacologic targets, revealing that NF1-null melanomas are dependent on RAS activation and that MEK inhibition relieves ERK-dependent negative feedback, increasing RAS signaling. MEK inhibition with avutometinib abrogates the adaptive rebound in ERK signaling, but the antitumor effects are limited. However, concurrent inhibition of MEK and SOS1 abrogates ERK activation, induces cell death, and suppresses tumor growth. In contrast to the NF1-deficient setting, concurrent SOS1 and SOS2 depletion is required to completely inhibit RAS signaling in NF1 wild-type cells. In sum, our data provide a mechanistic rationale for enhancing the therapeutic efficacy of MEK inhibitors by exploiting the lower residual SOS activity in NF1-null tumor cells., Competing Interests: Declaration of interests M.H.H., D.G., and F.S. are employees of Boehringer Ingelheim. T.M. is a consultant for Immunos Therapeutics, Daiichi Sankyo Co, TigaTX, Normunity, and Pfizer; is a cofounder of and equity holder in IMVAQ Therapeutics; has received research grants funding from Surface Oncology, Kyn Therapeutics, Infinity Pharmaceuticals, Peregrine Pharmaceuticals, Adaptive Biotechnologies, Leap Therapeutics, and Aprea Therapeutics; currently receives research funding from Bristol Myers Squibb, Enterome SA, and ReAlta Life Sciences; and is an inventor on patent applications related to work on oncolytic viral therapy, alpha virus-based vaccine, neoantigen modeling, CD40, GITR, OX40, PD-1, and CTLA-4. J.D.W. is a consultant for Apricity, Ascentage Pharma, AstraZeneca, BeiGene, Bicara Therapeutics, Bristol Myers Squibb, Daiichi Sankyo, Dragonfly, Imvaq, Larkspur, Takeda, Tizona, Trishula Therapeutics, Immunocore (on their data safety board), and Scancell; received grant/research support from Bristol Myers Squibb and Enterome; has equity in Apricity, Arsenal IO/CellCarta, Ascentage, Imvaq, Linneaus, Larkspur, Georgiamune, Maverick, Tizona Therapeutics, and XenImmune; and is an inventor on the following patents: Xenogeneic DNA Vaccines, Newcastle Disease Viruses for Cancer Therapy, Myeloid-Derived Suppressor Cell Assay, Prediction of Responsiveness to Treatment with Immunomodulatory Therapeutics and Method of Monitoring Abscopal Effects During Such Treatment, Anti-PD1 Antibody, Anti-CTLA4 Antibodies, and Anti-GITR Antibodies and Methods of Use Thereof. Z.Y. is a past scientific advisory board (SAB) member of MapKure and currently an employee of Loxo Oncology at Lilly. D.S. reports personal fees from Pfizer, Vividion Therapeutics, BridgeBio, FogPharma, FORE Therapeutics, Scorpion Therapeutics, and Rain Therapeutics outside the submitted work. S.M. reports grants from Boehringer Ingelheim and Daiichi Sankyo outside the submitted work and is a SAB member of Bionseek. N.R. is on the SAB and owns equity in BeiGene, Zai Labs, MapKure, Ribon, and Effector; is also on the SAB of AstraZeneca and Chugai and a past SAB member of Novartis, Millennium-Takeda, Kura, and Araxes; and is a consultant to Revolution Medicines, Tarveda, Array-Pfizer, Boehringer Ingelheim, and Eli Lilly. He receives research funding from Revolution Medicines, AstraZeneca, Array Pfizer, and Boehringer Ingelheim and owns equity in Kura Oncology and Fortress., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Identifying cancer therapy resistance is a key time-saving tool for physicians. Part of chemotherapy resistance includes senescence, a persistent state without cell division or cell death. Chemically inducing senescence with the combination of trametinib and palbociclib (TP) yields several tumorigenic and prometastatic factors in pancreatic cancer models with many potential antibody-based targets. In particular, urokinase plasminogen activator receptor (uPAR) has been shown to be a membrane-bound marker of senescence in addition to an oncology target. Methods: Here, 2 antibodies against murine uPAR and human uPAR were developed as immuno-PET agents to noninvasively track uPAR antigen abundance. Results: TP treatment increased cell uptake both in murine KPC cells and in human MiaPaCa2 cells. In vivo, subcutaneously implanted murine KPC tumors had high tumor uptake with the antimurine uPAR antibody independently of TP in young mice, yet uPAR uptake was maintained in aged mice on TP. Mice xenografted with human MiaPaCa2 tumors showed a significant increase in tumor uptake on TP therapy when imaged with the antihuman uPAR antibody. Imaging with either uPAR antibody was found to be more tumor-selective than imaging with [ 18 F]FDG or [ 18 F]F-DPA-714. Conclusion: The use of radiolabeled uPAR-targeting antibodies provides a new antibody-based PET imaging candidate for pancreatic cancer imaging as well as chemotherapy-induced senescence., (© 2024 by the Society of Nuclear Medicine and Molecular Imaging.)

Intratumoral heterogeneity in pancreatic ductal adenocarcinoma (PDAC) is characterized by a balance between basal and classical epithelial cancer cell states, with basal dominance associating with chemoresistance and a dismal prognosis. Targeting oncogenic KRAS, the primary driver of pancreatic cancer, shows early promise in clinical trials, but efficacy is limited by acquired resistance. Using genetically engineered mouse models and patient-derived xenografts, we find that basal PDAC cells are highly sensitive to KRAS inhibitors. Employing fluorescent and bioluminescent reporter systems, we longitudinally track cell-state dynamics in vivo and reveal a rapid, KRAS inhibitor-induced enrichment of the classical state. Lineage tracing uncovers that these enriched classical PDAC cells are a reservoir for disease relapse. Genetic or chemotherapy-mediated ablation of the classical cell state is synergistic with KRAS inhibition, providing a preclinical proof of concept for this therapeutic strategy. Our findings motivate combining classical state-directed therapies with KRAS inhibitors to deepen responses and counteract resistance in pancreatic cancer. Significance: KRAS inhibitors hold promise in pancreatic cancer, but responses are limited by acquired resistance. We find that a classical epithelial cancer cell state is acutely resistant to KRAS inhibition and serves as a reservoir for disease relapse. Targeting the classical state alongside KRAS inhibition deepens responses, revealing a potent therapeutic strategy. See related commentary by Marasco and Misale, p. 2018., (©2024 American Association for Cancer Research.)

The intricate network of protein-chaperone interactions is crucial for maintaining cellular function. Recent discoveries have unveiled the existence of specialized chaperone assemblies, known as epichaperomes, which serve as scaffolding platforms that orchestrate the reconfiguration of protein-protein interaction networks, thereby enhancing cellular adaptability and proliferation. This study explores the structural and regulatory aspects of epichaperomes, with a particular focus on the role of post-translational modifications (PTMs) in their formation and function. A key finding is the identification of specific PTMs on HSP90, particularly at residues Ser226 and Ser255 within an intrinsically disordered region, as critical determinants of epichaperome assembly. Our data demonstrate that phosphorylation of these serine residues enhances HSP90's interactions with other chaperones and co-chaperones, creating a microenvironment conducive to epichaperome formation. Moreover, we establish a direct link between epichaperome function and cellular physiology, particularly in contexts where robust proliferation and adaptive behavior are essential, such as in cancer and pluripotent stem cell maintenance. These findings not only provide mechanistic insights but also hold promise for the development of novel therapeutic strategies targeting chaperone assemblies in diseases characterized by epichaperome dysregulation, thereby bridging the gap between fundamental research and precision medicine., (© 2024. The Author(s).)

Purpose: Desmoplastic small round cell tumor (DSRCT) is a rare but highly aggressive soft tissue sarcoma that arises in the abdominopelvic cavity of young males. Since the discovery of EWSR1::WT1 fusion as the driver of DSRCT, no actionable genomic alterations have been identified, limiting disease management to a combination of surgery, chemotherapy, and radiation, with very poor outcomes. Herein, we evaluated ERBB2/HER2 expression in DSRCT as a therapeutic target., Experimental Design: ERBB2/HER2 expression was assessed in clinical samples and patient-derived xenografts (PDX) using RNA sequencing, RT-qPCR, and a newly developed HER2 IHC assay (clone 29D8). Responses to HER2 antibody-drug conjugates (ADC)-trastuzumab deruxtecan (T-DXd) and trastuzumab emtansine-were evaluated in DSRCT PDX, cell line, and organoid models. Drug internalization was demonstrated by live microscopy. Apoptosis was evaluated by Western blotting and caspase activity assays., Results: ERBB2/HER2 was detectable in DSRCT samples from patients and PDXs, with higher sensitivity RNA assays and improved IHC detectability using clone 29D8. Treatment of ERBB2/HER2-expressing DSRCT PDX, cell line, and organoid models with T-DXd or trastuzumab emtansine resulted in tumor regression. This therapeutic response was long-lasting in T-DXd-treated xenografts and was mediated by rapid HER2 ADC complex internalization and cytotoxicity, triggering p53-mediated apoptosis and growth arrest. Xenograft regression was associated with bystander payload effects triggering global tumor niche responses proportional to HER2 status., Conclusions: ERBB2/HER2 is a therapeutic target in DSRCT. HER2 ADCs may represent novel options for managing this exceptionally aggressive sarcoma, possibly fulfilling an urgent and historically unmet need for more effective clinical therapy., (©2024 American Association for Cancer Research.)

Anaplastic thyroid cancer (ATC) is a clinically aggressive malignancy with a dismal prognosis. Combined BRAF/MEK inhibition offers significant therapeutic benefit in patients with BRAF V600E -mutant ATCs. However, relapses are common and overall survival remains poor. Compared with differentiated thyroid cancer, a hallmark of ATCs is significant infiltration with myeloid cells, particularly macrophages. ATCs are most common in the aging population, which also has an increased incidence of TET2 -mutant clonal hematopoiesis (CH). CH-mutant macrophages have been shown to accelerate CH-associated pathophysiology including atherosclerosis. However, the clinical and mechanistic contribution of CH-mutant clones to solid tumour biology, prognosis and therapeutic response has not been elucidated. Here we show that TET2 -mutant CH is enriched in the tumour microenvironment of patients with solid tumours and associated with adverse prognosis in ATC patients. We find that Tet2 -mutant macrophages selectively infiltrate mouse Braf V600E -mutant ATC and that their overexpression of Tgfβ-family ligands mediates resistance to BRAF/MEK inhibition. Importantly, inhibition of Tgfβ signaling restores sensitivity to MAPK pathway inhibition, opening a path for synergistic strategies to improve outcomes of patients with ATCs and concurrent CH.

The translocation t(14;18) activates BCL2 and is considered the initiating genetic lesion in most follicular lymphomas (FL). Surprisingly, FL patients fail to respond to the BCL2 inhibitor, Venetoclax. We show that mutations and deletions affecting the histone lysine methyltransferase SETD1B (KMT2G) occur in 7% of FLs and 16% of diffuse large B cell lymphomas (DLBCL). Deficiency in SETD1B confers striking resistance to Venetoclax and an experimental MCL-1 inhibitor. SETD1B also acts as a tumor suppressor and cooperates with the loss of KMT2D in lymphoma development in vivo. Consistently, loss of SETD1B in human lymphomas typically coincides with loss of KMT2D. Mechanistically, SETD1B is required for the expression of several proapoptotic BCL2 family proteins. Conversely, inhibitors of the KDM5 histone H3K4 demethylases restore BIM and BIK expression and synergize with Venetoclax in SETD1B-deficient lymphomas. These results establish SETD1B as an epigenetic regulator of cell death and reveal a pharmacological strategy to augment Venetoclax sensitivity in lymphoma., (© 2024 Portelinha et al.)

Chimeric antigen receptor (CAR) T-cell therapy has resulted in remarkable clinical success in the treatment of B-cell malignancies. However, its clinical efficacy in solid tumors is limited, primarily by target antigen heterogeneity. To overcome antigen heterogeneity, we developed CAR T cells that overexpress LIGHT, a ligand of both lymphotoxin-β receptor on cancer cells and herpes virus entry mediator on immune cells. LIGHT-expressing CAR T cells displayed both antigen-directed cytotoxicity mediated by the CAR and antigen-independent killing mediated through the interaction of LIGHT with lymphotoxin-β receptor on cancer cells. Moreover, CAR T cells expressing LIGHT had immunostimulatory properties that improved the cells' proliferation and cytolytic profile. These data indicate that LIGHT-expressing CAR T cells may provide a way to eliminate antigen-negative tumor cells to prevent antigen-negative disease relapse., (©2024 American Association for Cancer Research.)

Patients with small-cell lung cancer (SCLC) have poor prognosis and typically experience only transient benefits from combined immune checkpoint blockade (ICB) and chemotherapy. Here, we show that inhibition of ataxia telangiectasia and rad3 related (ATR), the primary replication stress response activator, induces DNA damage-mediated micronuclei formation in SCLC models. ATR inhibition in SCLC activates the stimulator of interferon genes (STING)-mediated interferon signaling, recruits T cells, and augments the antitumor immune response of programmed death-ligand 1 (PD-L1) blockade in mouse models. We demonstrate that combined ATR and PD-L1 inhibition causes improved antitumor response than PD-L1 alone as the second-line treatment in SCLC. This study shows that targeting ATR up-regulates major histocompatibility class I expression in preclinical models and SCLC clinical samples collected from a first-in-class clinical trial of ATR inhibitor, berzosertib, with topotecan in patients with relapsed SCLC. Targeting ATR represents a transformative vulnerability of SCLC and is a complementary strategy to induce STING-interferon signaling-mediated immunogenicity in SCLC.

Purpose: MDM2, a negative regulator of the TP53 tumor suppressor, is oncogenic when amplified. MDM2 amplification (MDM2amp) is mutually exclusive with TP53 mutation and is seen in 6% of patients with lung adenocarcinoma (LUAD), with significant enrichment in subsets with receptor tyrosine kinase (RTK) driver alterations. Recent studies have shown synergistic activity of MDM2 and MEK inhibition in patient-derived LUAD models with MDM2amp and RTK driver alterations. However, the combination of MDM2 and RTK inhibitors in LUAD has not been studied., Methods: We evaluated the combination of MDM2 and RTK inhibition in patient-derived models of LUAD., Results: In a RET-fusion LUAD patient-derived model with MDM2amp, MDM2 inhibition with either milademetan or AMG232 combined with selpercatinib resulted in long-term in vivo tumor control markedly superior to either agent alone. Similarly, in an EGFR-mutated model with MDM2amp, combining either milademetan or AMG232 with osimertinib resulted in long-term in vivo tumor control, which was strikingly superior to either agent alone., Conclusion: These preclinical in vivo data provide a rationale for further clinical development of this combinatorial targeted therapy approach.

Despite therapeutic efficacy observed with immune checkpoint blockade in advanced melanoma, many tumors do not respond to treatment, representing a need for new therapies. Here, we have generated chimeric antigen receptor (CAR) T cells targeting TYRP1, a melanoma differentiation antigen expressed on the surface of melanomas, including rare acral and uveal melanomas. TYRP1-targeted CAR T cells demonstrate antigen-specific activation and cytotoxic activity in vitro and in vivo against human melanomas independent of the MHC alleles and expression. In addition, the toxicity to pigmented normal tissues observed with T lymphocytes expressing TYRP1-targeted TCRs was not observed with TYRP1-targeted CAR T cells. Anti-TYRP1 CAR T cells provide a novel means to target advanced melanomas, serving as a platform for the development of similar novel therapeutic agents and as a tool to interrogate the immunobiology of melanomas., Competing Interests: C.S.H., D.H., T.J.P., S.R., J.D.W., T.M., and R.J.B. are inventors on multiple patents filed by MSK covering CAR T cell technology, including the CAR T cells discussed in this manuscript. S.R. serves on the Scientific Advisory Board of Celyad Oncology. R.J.B. has licensed intellectual property to and collects royalties from BMS, Caribou, and Sanofi. R.J.B. received research funding from BMS. R.J.B. is a consultant to BMS, Atara Biotherapeutics Inc., and Triumvira, and was a consultant for Cargo Tx and CoImmune but ended in the past 3 months, and Gracell Biotechnologies Inc. but ended employment in the past 24 months. R.J.B. is a member of the scientific advisory board for Triumvira and was a member of the scientific advisory board for Cargo Tx and CoImmune, but that ended in the past 6 months. J.D.W. is a consultant for Apricity, Ascentage Pharma, AstraZeneca, BeiGene, Bicara Therapeutics (ending 4/1/2024), Bristol Myers Squibb, Daiichi Sankyo, Dragonfly, Imvaq, Larkspur, Psioxus, Recepta, Takeda, Tizona, Trishula Therapeutics, and Sellas. J.D.W. received grant/research support from Bristol Myers Squibb and Enterome. J.D.W. has equity in Apricity, Arsenal IO/CellCarta, Ascentage, Imvaq, Linneaus, Larkspur, Georgiamune, Maverick, Tizona Therapeutics, and Xenimmune. J.D.W. is an inventor on the following patents: Xenogeneic DNA Vaccines, Newcastle Disease viruses for Cancer Therapy, Myeloid-derived suppressor cell (MDSC) assay, Prediction of responsiveness to treatment with immunomodulatory therapeutics and method of monitoring abscopal effects during such treatment, Anti-PD1 Antibody, Anti-CTLA4 antibodies, Anti-GITR antibodies and methods of use thereof. T.M. is a consultant for Immunos Therapeutics, Daiichi Sankyo Co, TigaTX, Normunity, and Pfizer. T.M. is a cofounder of and equity holder in Imvaq Therapeutics. T.M. receives research grant funding from Bristol Myers Squibb, Surface Oncology, Kyn Therapeutics, Infinity Pharmaceuticals, Peregrine Pharmaceuticals, Adaptive Biotechnologies, Leap Therapeutics, and Aprea Therapeutics. T.M. is an inventor on patent applications related to work on oncolytic viral therapy, alpha virus-based vaccine, neo-antigen modeling, CD40, GITR, OX40, PD-1, and CTLA-4., (© 2024 The Author(s). Published by Elsevier Inc. on behalf of The American Society of Gene and Cell Therapy.)