Cancer Letters

Mcl1 is a major driver of therapeutic resistance across hematologic malignancies, but direct Mcl1 inhibition has been limited by on-target cardiotoxicity. Here, building on our development of an Mcl1-targeting autophagy-targeting chimera (AUTAC), we show that AUTAC-mediated degradation creates a tumor-selective therapeutic window that spares the heart. AUTAC induced robust cytotoxicity and Mcl1 degradation in multiple myeloma models, while showing minimal toxicity in cardiac cell lines, primary cardiomyocytes, and murine heart tissue. In vivo, AUTAC reduced tumor Mcl1 without measurably affecting cardiac Mcl1. Mechanistically, this selectivity was associated with lower expression of the p62/SQSTM1, TRAF6, and UBC13 machinery required for AUTAC activity in cardiac cells, together with lower intracellular AUTAC accumulation relative to tumor cells. AUTAC also enhanced the antitumor activity of carfilzomib and venetoclax, including in resistant models, without worsening cardiotoxicity or promoting cardiac Mcl1 loss. Compared with classical Mcl1 inhibitors, AUTAC caused markedly less cardiomyocyte death, mitochondrial depolarization, and apoptotic signaling. These findings identify AUTAC-mediated Mcl1 degradation as a cardiac-sparing strategy to target an otherwise clinically constrained vulnerability and support tumor-selective lysosomal degradation as a path to safer Mcl1-directed therapy.

Although KRAS G12C-specific inhibitors such as sotorasib have been approved by US FDA and currently used in clinic, treating non-G12C mutants and overcoming acquired resistance for these inhibitors remain critical challenges. Here, we introduce a reciprocal feedback blockade therapy combining the MEK inhibitor trametinib and the multi-tyrosine kinase inhibitor imatinib to overcome these limitations. Our study reveals their compensatory roles: trametinib suppresses MEK activity yet promotes tyrosine kinase signaling and angiogenesis, while imatinib, a pan-tyrosine kinase inhibitor unleashes the MEK/ERK pathway via phosphatase suppression. Combining these agents blocks the reciprocal survival signals, inducing robust cell death across diverse KRAS-mutant models. Mechanistically, this combination reprograms cellular metabolism, leading to autophagy-dependent lipid peroxidation accumulation and ferroptosis. This strategy was effective in sotorasib-resistant lung cancer cells and various mouse models, including pancreatic cancer patient-derived xenograft. Furthermore, a pilot clinical trial for KRAS-mutant pancreatic cancer yielded encouraging responses. Consequently, the trametinib-imatinib combination represents a promising, broad-spectrum therapeutic strategy to overcome the constraints of current KRAS-targeted therapies.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most challenging cancers to treat due to the dismal survival rate, poor post-treatment outcome and profound resistance to a wide range of therapies. With mutant KRAS being a key driver, small molecule inhibitors targeting KRAS or pan-RAS (KRASi) have demonstrated exciting preclinical and early clinical anti-tumor efficacy, and the pan-RAS(ON) inhibitor daraxonrasib (RMC-6236) recently achieved Phase 3 clinically meaningful improvements in patient survival compared to chemotherapy. But resistance to RAS/KRAS inhibitor inevitably develops, which limits and compromises the treatment outcome. In this study, we investigated the combination of stereotactic body radiation therapy (SBRT) and KRAS inhibition (MRTX1133 and daraxonrasib) in the treatment of preclinical PDAC models. We found that this combination strategy synergistically suppresses PDAC cell growth in vitro and enhances tumor control while minimizing local recurrence in orthotopically implanted KPC (LSL-KrasG12D/+;Trp53R172H/+;Pdx1-Cre) murine PDAC tumors in vivo. As radiation therapy (RT) induces ferroptosis in multiple cancer types and mutant KRAS promotes various anti-ferroptotic mechanisms, we tested the role of ferroptosis in promoting tumor-control efficacy. Intriguingly, the addition of a ferroptosis inhibitor, liproxstatin-1, to the combination therapy significantly abrogated the in vivo synergism between SBRT and KRAS inhibition, suggesting that treatment-induced ferroptosis at least partially drives the synergistic efficacy of this combination strategy. Our study indicates that this SBRT-KRASi combination has the potential to overcome treatment resistance and improve outcomes in PDAC patients. These data directly support the design of a planned multi-center Phase 2 clinical trial with this combination strategy in locally advanced PDAC.

Regardless of the success of clinical surgery, disseminated tumor cells (DTCs) can persist in distant organs, with a fraction surviving chemotherapy, which can result in minimal residual disease (MRD), a relevant reservoir for metastatic relapse. Yet, the cellular states that enable the survival and outgrowth of MRD remain poorly defined. Here, using a patient-derived tongue cancer organoid (TCO) model, we recapitulated the key features of chemotherapy-tolerant DTCs by culturing TCOs under growth-factor deprivation and chemotherapeutic stress conditions that mimic the metastatic tissue environment. Clonal-level analyses revealed a distinct subset of cells that retained proliferative capacity without entering a therapy-induced cytostatic state (hereafter referred to as cycling persisters, CPs). CPs exhibited coordinated activation of the IFN signaling pathway, Xenobiotic metabolism, and inflammatory signaling pathways, defining a transcriptional and metabolic program that enables sustained proliferation of CPs under the poor conditions. Consistently, a cell population with similar features was identified in metastatic tissues from patients. Longitudinal clonal tracking demonstrated that early metastatic recurrence is more likely driven by CPs, suggesting a novel mechanism that differs from the prevailing view that relapse arises from reactivation of dormant non-CPs. Our findings highlight a critical therapeutic oversight in relapse prevention.

IntroductionThe RAS(ON) multi-selective daraxonrasib (RMC-6236) inhibitor is effective in patients with NSCLC KRAS mutant cancers. Tolerance to daraxonrasib invariably develops by mechanisms that remain unclear. There is no known involvement of the M1C oncogenic protein in daraxonrasib resistance. MethodsNSCLC H358 KRAS(G12C), H2122 KRAS(G12C) and patient derived MGH1112 KRAS(G12C) cells with acquired daraxonrasib resistance were investigated for M1C dependence in studies of SHP2, STAT1/3 and NF-KB activation, clonogenicity, and self-renewal capacity. ResultsWe demonstrate that M1C is induced as a protective response in NSCLC KRAS(G12C) mutant cells treated with daraxonrasib. We report that M1C forms novel cell membrane-associated biomolecular condensates with the SHP2 protein tyrosine phosphatase in driving daraxonrasib resistance. M1C integrates SHP2 activation with induction of (i) oncostatin-m/gp130/STAT3 signaling, and (ii) the NF-{kappa}B-mediated epithelial-mesenchymal transition (EMT) pathway. The functional significance of this M1C-driven pathway is supported by the demonstration that targeting STAT3 and NF-{kappa}B reverses daraxonrasib resistance. Consistent with M1C dependence, we also show that targeting M1C is effective against daraxonrasib-resistant NSCLC KRAS mutant cell line and tumor models. In contrast, M1C drives sotorasib resistance by STAT1-mediated inflammatory signaling, demonstrating that M1C confers resistance to KRAS(G12C)-selective and RAS(ON) tri-complex inhibitors by noncongruent mechanisms. ConclusionsThese findings demonstrate that M1C is required for daraxonrasib tolerance and is a potential target for the treatment of patients with NSCLC KRAS(G12C) mutant tumors refractory to this agent.

Pancreatic ductal adenocarcinoma (PDAC) remains a lethal malignancy with limited therapeutic options, underscoring the need for innovative treatments. Chimeric antigen receptor (CAR) therapy has transformed hematologic malignancies but faces key challenges in solid tumors, particularly on-target/off-tumor toxicity and antigen heterogeneity. Adapter CAR (AdCAR) platforms offer enhanced control by decoupling antigen recognition from CAR activation, enabling controllable, reversible, and multi-antigen targeting. Recent studies suggest AdCARs can function as an AND-gate using combinations of adapter molecules at controlled surface densities. This defines activation thresholds, termed the Surface Activation Matrix, that restricts full activation to tumor cells overexpressing the target antigen combination, thereby reducing off-tumor toxicity. In this study, we evaluated its applicability to PDAC using adapters targeting CD318, TSPAN8 and CD66c. We systematically evaluated single and combinatorial adapter dosing in co-culture assays with AsPC1 cells, in a donor-dependent manner. Low concentrations of individual adapters were non-cytotoxic, whereas combining them at identical sub-threshold doses restored potent tumor killing, demonstrating that AdCAR activation depends on cumulative adapter density rather than total amount. However, the activation threshold required for AND-gate cytotoxicity varied between donors, highlighting the need for patient-specific titration to achieve selective tumor killing. These findings validate that AdCAR T cell activity in PDAC can be finely tuned through adapter concentration and combinatorial targeting, enabling selective tumor recognition while minimizing on-target/off-tumor toxicity. This flexible, safety-oriented strategy supports targeting heterogeneous PDAC tumors, though donor-dependent variability remains a critical consideration for clinical implementation.

Abstract Background: The lack of effective biomarkers and therapeutic targets to overcome radioresistance in cervical cancer remains a major clinical challenge. Tumor necrosis factor receptor-associated factor 6 (TRAF6), an E3 ubiquitin ligase pivotal in immune and inflammatory signaling, has been implicated in various malignancies. However, its role in radioresistance in cervical cancer remains unclear. Methods: TRAF6 expression was evaluated in cervical cancer tissues from 162 patients who underwent postoperative radiotherapy at our institution and in 304 cases from the TCGA-CESC cohort. The prognostic significance of TRAF6 was assessed using Kaplan-Meier and Cox regression analyses. A nomogram integrating TRAF6 expression with clinicopathological factors was constructed to predict overall survival (OS) and progression-free survival (PFS). The functional role of TRAF6 in malignant phenotypes and radiosensitivity was investigated using shRNA-mediated knockdown in HeLa and C33A cervical cancer cells. Immune cell infiltration patterns associated with TRAF6 expression were analyzed using ssGSEA and xCELL algorithms based on TCGA data. Results: TRAF6 expression was significantly elevated in cervical cancer tissues compared with adjacent normal tissues (70.99% vs. control, P < 0.001) and was higher in radioresistant than in radiosensitive patients (P < 0.001). High TRAF6 expression was associated with shorter OS (HR = 18.73, P = 0.004) and PFS (HR = 8.44, P < 0.001) and was identified as an independent risk factor for radiotherapy resistance (OR = 8.44, P < 0.001). The TRAF6-integrated nomogram demonstrated good predictive accuracy for OS (C-index = 0.7351) and PFS (C-index = 0.7444). TRAF6 knockdown in cervical cancer cells significantly suppressed proliferation, migration, and invasion, while substantially enhancing radiosensitivity of tumor cells. Functional enrichment analysis revealed that TRAF6-related genes were enriched in autophagy, mitophagy, and HPV infection pathways. Immune cell infiltration analysis showed that TRAF6 expression correlated with distinct immune cell profiles, characterized by enrichment of activated dendritic cells, M1 macrophages, and regulatory T cells, alongside depletion of cytotoxic effectors such as CD8+ T cells and {gamma}{delta} T cells. Conclusions: TRAF6 could be a prognostic biomarker associated with poor outcomes and indicator of radiotherapy resistance in cervical cancer, TRAF6 represents a potential therapeutic target for overcoming radioresistance in cervical cancer.

The epidermal growth factor receptor (EGFR) expression is often dysregulated in head and neck squamous cell carcinoma (HNSCC), driving cancer cell proliferation, invasion, and metastasis through diverse pathways, thereby contributing to aggressive chemo- and radio-therapy resistance. A GPI-anchored protein, CD109 is upregulated in multiple cancers, including HNSCC. While membrane-anchored CD109 (mCD109) is pro-tumorigenic in SCC via EGFR/STAT3 activation, the role of protease-cleaved soluble CD109 (sCD109) is poorly understood. Our groundbreaking findings demonstrate that sCD109 antagonizes EGFR signaling by directly binding to the EGFR extracellular domain, preventing mCD109-EGFR stabilizing interactions on the cell surface, followed by inhibition of EGFR phosphorylation at Y1068 and downstream signaling cascades (AKT, MAPK, and STAT3) consequently suppressing cancer cell migration, invasion, 3D tumor spheroid formation and angiogenic tube formation. In addition, we found that sCD109 regulates EGFR fates by inhibiting nuclear localization of phosphorylated EGFR and promoting EGFR degradation. Additionally, sCD109 significantly reduces EGF-induced expression of cancer stem cell markers (CD44 and CD133) and embryonic stem cell markers (Nanog and Sox2), suggesting a suppressive role in cancer stemness. Taken together, these results underscore the opposing roles of mCD109 and sCD109: with sCD109 acting as an antagonist by inhibiting mCD109/EGFR-driven oncogenic signaling and phenotypes. Our current findings reveal a complex interplay among mCD109, sCD109, and EGFR, identifying a mechanism for targeting EGFRs degradation in HNSCC, and lay the groundwork for future research on investigating sCD109s modulatory role in preclinical models of HNSCC.

Genetic uniqueness of the tumor microenvironment significantly influences cancer growth, survival, and response to therapy, independent of the cancer cells intrinsic properties or the adaptive immune system. Using genetically distinct Rag1-/- mouse models, this study shows that different strains exhibit varied tumor growth kinetics and survival outcomes when xenografted with identical leukemic and solid tumor cell lines. This study further highlights the critical role of the myeloid immune compartment and shows that disrupting both lymphoid and myeloid systems alters cancer progression. These results also reveal that the tumor microenvironment can permanently alter cancer cell phenotypes and significantly affect chemotherapy efficacy, as seen with Cisplatins varying effects across strains. These findings underscore the importance of considering genetic background in preclinical cancer models, suggesting that reliance upon a single mouse strain may lead to incomplete conclusions about cancer biology and treatment efficacy. SUMMARY STATEMENTPre-clinical xenograft mammalian models are used to study human diseases. Here we report that the genetic uniqueness of the tumor microenvironment, independent of the immune system, can determine the fate of cancer progression, survival, and therapy response.

Small cell lung cancer (SCLC) is a highly aggressive malignancy with limited therapeutic advances. Unlike many other cancers, its immune landscape, particularly immune competence and T cell recognition, remains poorly characterized. Here, we generate a single-cell transcriptome atlas of the SCLC immune microenvironment with paired T cell receptor (TCR) sequencing. By linking T cell states with clonality and a multilayered functional screening, we identify 6 tumor-reactive TCRs that recognize and eradicate autologous SCLC cell lines. We delineate a novel SCLC-reactive CD8+ T cell signature (SCLC_TR), enabling the identification of 47 further SCLC-reactive TCRs. The SCLC_TR signature performs extremely well in pancreatic ductal adenocarcinoma (PDAC), another immune-cold tumor indication, and, most strikingly, patients with elevated SCLC_TR signature scores exhibited significantly improved survival, underlining its prognostic potential. Comparative cell-cell interaction analyses implicate several immunosuppressive mechanisms, with myeloid cells and CD4+ regulatory T cells possibly acting as counterbalances to effector T cell activity in SCLC. In summary, our study challenges the prevailing notion of SCLC as an immune-cold tumor type by providing direct evidence of tumor-reactive T cell responses and introduces the SCLC_TR signature as a tool to identify tumor-specific T cells and their microenvironmental restraints and escape mechanisms, ultimately shaping next-generation immunotherapeutic strategies.

Cytotoxic T lymphocytes (CTLs) play a central role in antitumor immunity; however, metabolic reprogramming within the tumor microenvironment often compromises their effector function, making metabolic targeting crucial for the improvement of T cell function. Folate-dependent purine synthesis, a core pathway sustaining the nucleotide pool, is highly activated in tumors, yet its role in regulating tumor immune sensitivity remains unclear. Here, by establishing a co-culture system of melanoma cells and human T Cell Receptor (TCR)-engineered T cells, we systematically evaluated the effects of folate-dependent purine synthesis inhibitors on tumor cell response to CD8+ T cell cytotoxicity. We found that inhibition of key enzymes such as methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) and glycinamide ribonucleotide transformylase (GART) markedly enhanced tumor cell sensitivity to T cell killing, an effect also observed with exogenous nucleoside supplementation. Mechanistically, inhibition of folate-dependent purine synthesis suppresses glycolysis by downregulating critical glycolytic enzymes, thereby reducing lactate production. Reduction in lactate further weakens lactylation and stability of the immune checkpoint protein PD-L1. In parallel, impaired purine synthesis disrupts uridine metabolism, blocks ribose salvage, and distally influences glycolysis. Collectively, our study identified the folate-dependent purine synthesis-glycolysis axis as key regulator of tumor immune response and highlights metabolic targeting as a promising strategy to improve cancer immunotherapy.

Background Patients with advanced pancreatic ductal adenocarcinoma (aPDAC) often experience general health decline at diagnosis due to a high-symptom burden. The optimal management of symptoms and/or poor performance status (PS) in these patients remains an unmet medical need. Patients and Methods In this multicenter study, patients with PS[&ge;]2 and pathologically confirmed or imaging-suspected aPDAC were included at first oncology visit in a personalized 14-day emergency integrative supportive care program (14-EISCP) to manage pain, nutrition, diagnostics, and stenting procedures. The primary endpoint was the 14-EISCP success in feasibility of planned procedures and clinical benefit defined as post-EISCP PS[&le;]1, [&ge;]5 points improvement in fatigue, pain, global health-related quality of life (HRQoL) scores (EORTC QLQ-C15-PAL), or chemotherapy initiation within 30 days. Results A total of 106 patients were included; 93 evaluable patients considered for primary endpoint analysis (median age: 76 years [68-80], PS3: 20.9%, metastases: 61.3%). The median overall survival was 4.1 months (IC95% 2.6-5.6). The 14-EISCP was successful in 59.1% (n=55) of patients, meeting the primary objective (clinically relevant). The 14-EISCP feasibility was achieved in 70.9% of cases. Post-EISCP clinical benefit was observed in 79.6% of patients, with PS improvement to 0/1 in 13.2%, HRQoL improvement in 23.9%, and chemotherapy initiation [&le;]30 days in 73.1%. Among evaluable patients, 17.2% received mFOLFIRINOX or gemcitabine-nab-paclitaxel, 35.4% received FOLFOX, 25.3% had gemcitabine or 5-fluorouracil alone, and 22.2% received best supportive care. In patients with PS2 at baseline, the administration of doublet/triplet chemotherapy was associated with improved overall survival compared to single-agent. Discussion These results offer a promising framework for improving outcomes in aPDAC patients, bridging the gap between symptom management and systemic therapy administration. Conclusions In patients with PS[&ge;]2 and aPDAC, the personalized 14-EISCP was feasible and lead to meaningful clinical benefit, allowing doublet or triplet chemotherapy in half the patients.

Hepatocellular carcinomas (HCC) are genetically heterogeneous cancers frequently characterized by MYC gene amplification or hyperactivating {beta}-catenin (CTNNB1) mutations. Analysis of TCGA transcriptomics revealed that MYC-driven HCC tumors have decreased expression of mtDNA-encoded genes, but increased expression of nuclear-encoded mitochondrial genes. To investigate this apparent discrepancy, we generated MYC- and CTNNB1-driven murine HCCs, all of which displayed aberrant mitochondrial metabolism. Notably, MYC-driven tumors exhibited significant reductions in OXPHOS and TCA cycle activity that correlated with increased ROS levels, as well as elevated mitochondrial turnover through mitochondrial fission and mitophagy. MYC induces the expression of nuclear respiratory factor 1 (NRF1), which regulates DRP1 and other genes to promote receptor-mediated mitophagy. Knocking out DRP1 reduced mitophagy and ROS levels and promoted survival of HCC-bearing mice. These results identify elevated mitochondrial turnover as a potential therapeutic target in MYC-driven HCC. SignificanceHepatocellular carcinoma can arise from multiple oncogenes, making targeted therapy more difficult. Here we show that tumors with MYC amplification lose mitochondrial function via fission and mitophagy upregulation. Targeting mitochondrial quality control results in increased survival suggesting a therapeutic window in MYC-driven HCC.

Glioblastoma (GBM) is a highly lethal brain cancer with limited therapeutic durability, where the majority of patients develop recurrent or persistent disease after standard chemoradiotherapy. Meanwhile, tRNA-derived fragments (tRFs) have become increasingly relevant to cancer biology; however, their clinical relevance in GBM remains undefined. Here, we report that a specific family of tRFs, 5-tRNA halves (tiR5s) dominates the small RNA landscape of GBM patient tumors and associates with worse overall survival, post-therapeutic disease persistence, and pro-invasive proteogenomic pathways across two independent GBM patient cohorts. This association between elevated tiR5 levels and therapeutic resistance re-emerges in radiation-resistant GBM xenograft models. Our findings reveal that tiR5s are an underappreciated molecular feature of highly aggressive GBM tumors, supporting further investigation into their biological roles and prognostic utility in GBM. HighlightsO_LItiR5s are the predominant tRF family in primary GBM patient tumors C_LIO_LIElevated tiR5 expression distinguishes primary GBM tumors that develop persistent disease after first-line therapy C_LIO_LIRadiation-resistant GBM PDX models show elevated tiR5 expression C_LIO_LIElevated tiR5 expression associates with poor overall patient survival and pro-invasive molecular programs in GBM patient tumors C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/738483v1_ufig1.gif" ALT="Figure 1"> View larger version (54K): org.highwire.dtl.DTLVardef@184ddc1org.highwire.dtl.DTLVardef@1faadc2org.highwire.dtl.DTLVardef@a5ae02org.highwire.dtl.DTLVardef@1431506_HPS_FORMAT_FIGEXP M_FIG C_FIG

Intracellular iron homeostasis is increasingly recognized as a regulator of cancer cell behavior, but how iron distribution influences extracellular matrix (ECM) organization and invasion remains poorly understood. Here, we show that loss of divalent metal transporter 1 (DMT1/SLC11A2) disrupts intracellular iron homeostasis and promotes cancer cell invasion through an iron-ER-ECM axis. In MDA-MB-231 cells, DMT1 knockout (KO) reduced total iron content but increased the labile iron pool (LIP) in both 2D and 3D culture models, indicating altered intracellular iron distribution. Across transcriptomic and phenotypic readouts, DMT1-dependent effects were more evident in 3D than in 2D models, with DMT1 KO inducing endoplasmic reticulum (ER) stress and impaired collagen/ECM organization. Functionally, the DMT1-loss phenotype was marked by reduced 2D motility, whereas in 3D spheroid models DMT1 KO cells displayed enhanced invasive outgrowth in both Matrigel and collagen matrices. Iron chelation further modulated this phenotype in a DMT1-dependent manner. Pharmacologic induction of ER stress phenocopied the loose spheroid architecture and invasive behavior, supporting ER stress as a mechanistic link between altered iron handling and ECM destabilization. Together, these findings identify intracellular iron distribution, rather than total iron abundance alone, as a determinant of ECM integrity and context-dependent cancer cell invasion. Significance StatementOur study identifies an iron-ER-ECM axis through which intracellular iron homeostasis regulates cancer cell invasion. Total cellular iron content alone is insufficient to predict invasive behavior without considering how iron is distributed within the cell. By preserving intracellular iron homeostasis and ER function, DMT1 supports collagen synthesis and maintains ECM integrity. In contrast, DMT1 loss disrupts these processes, promoting formation of loosely aggregated spheroids and enhanced invasion in 3D tumor models despite reduced total iron levels. These findings challenge the assumption that lowering bulk iron uniformly suppresses invasive phenotypes and instead highlight intracellular iron trafficking as a potential therapeutic target for limiting cancer cell invasion.

Lung cancer is a highly heterogeneous disease and remains the leading cause of cancer-related mortality worldwide. While mouse models and patient-derived organoids have advanced our understanding of lung cancer, key interactions within the tumor microenvironment (TME) remain poorly characterized. We developed microtumor models from lung adenocarcinoma (LUAD) and small cell lung cancer (SCLC) using mouse and patient samples, including surgical resections and rapid autopsy specimens. Microtumors preserve structural, cellular, and molecular features of the native TME, enabling mechanistic studies of tumor progression ex vivo. Multi-omics analyses of LUAD microtumors revealed progression-associated changes, including increased epithelial-to-mesenchymal transition (EMT) and metabolic reprogramming toward fatty acid synthesis. Pharmacologic inhibition of fatty acid synthesis through ACC1/2 reduced proliferation in patient-derived microtumors, identifying a targetable vulnerability. This platform provides a robust system for studying tumor progression, therapeutic response, and resistance mechanisms in lung cancer, including culturing postmortem specimens that are not accessible in current models.

Pancreatic ductal adenocarcinoma (PDAC) is dependent on autophagy for growth. Chloroquine/Hydroxychloroquine (CQ/HCQ), the sole FDA-approved autophagy inhibitors, have shown limited clinical efficacy as cancer therapies. To identify approaches to improve PDAC response to CQ, we performed a CQ-anchored, CRISPR-Cas9 mediated loss-of-function screen. We identified that the loss of genes encoding proteins upstream in the autophagy pathway enhanced CQ-mediated growth suppression. This indicated that simultaneous targeting of two distinct nodes of the same pathway, vertical inhibition, may be a more effective strategy than single node inhibition. We demonstrated that genetic loss or pharmacological inhibition of VPS34, a protein necessary for autophagosome nucleation, sensitized PDAC cells to inhibitors of the terminal stage of the autophagy pathway, including CQ and an inhibitor of PIKfyve. We extended this concept to the initiation complex and demonstrated that ULK1/2 inhibition synergized with CQ and PIKfyve inhibition to impair PDAC cell growth and increase apoptosis. Anticipating mechanisms of resistance to vertical autophagy inhibition, we performed reverse-phase protein array profiling and identified that vertical inhibition of the autophagy pathway resulted in enhanced activation of the PI3K-AKT-mTORC1 signaling pathway. Increased mTORC1 signaling resulted in heightened sensitivity to bi-steric mTORC1 inhibition in both cell line and organoid models of PDAC. This study identifies novel anti-autophagy inhibitor combinations that may improve the clinical efficacy of autophagy inhibition for PDAC treatment. IMPLICATIONSVertical inhibition of the autophagy pathway reduces pancreatic cancer cell growth, increases apoptosis, and enhances sensitivity to mTORC1 inhibition; thereby representing a novel therapeutic strategy for autophagy-driven pancreatic cancer.

Background: Osimertinib is the standard first-line treatment for EGFR- mutant non-small cell lung cancer (NSCLC) harboring common activating mutations, including exon 19 deletions and L858R. It is also active against tumors with acquired T790M resistance. However, the EGFR L858R+T790M compound mutation, where both variants co-occur within the same tumor, may confer distinct drug-sensitivity profiles not predicted by either mutation alone. Limited data exist on comparative treatment outcomes in this rare genotype. Methods: Using the MSK-CHORD clinicogenomic dataset (n=24,950), we identified patients with concurrent EGFR L858R and T790M mutations receiving erlotinib (Erlo) or osimertinib (Osi) monotherapy. Real-world progression-free survival (rwPFS) per treatment line was calculated using a strict definition requiring confirmed radiological progression events (rwPFS-strict), excluding lines with null endpoint data. Kaplan-Meier analysis, log-rank testing, Cox proportional hazards regression, and cross-cohort heterogeneity testing (Cochran's Q statistic) were performed. Two control cohorts, L858R-only (n=372) and T790M-only (n=76), were analyzed in parallel to assess mutation-context specificity of treatment response. Results: Thirty-one patients with EGFR L858R+T790M were identified; 21 contributed evaluable monotherapy lines, yielding 23 Erlo and 15 Osi treatment lines (14 unique patients per treatment group, 7 contributing to both). Median rwPFS numerically favored Erlo over Osi (7.10 vs 5.32 months; HR 1.29, 95% CI 0.66-2.52; log-rank p=0.46). This directional trend was reversed in the L858R-only control cohort, where Osi demonstrated significant superiority (9.03 vs 5.75 months; HR 0.70, 95% CI 0.55-0.89; p=0.003). The T790M-only cohort showed no significant difference (HR 1.32, p=0.12). An exploratory post-hoc heterogeneity test confirmed a significant cross-cohort interaction (Q=9.94, df=2, p=0.007). Conclusions: The expected osimertinib advantage was absent in L858R+T790M compound-mutant NSCLC. The opposing hazard ratio directions across mutation contexts (HR 1.29 vs 0.70), with a significant exploratory cross-cohort interaction (p=0.007), suggest that the EGFR L858R+T790M compound mutation may represent a pharmacologically distinct entity with differential TKI sensitivity. These hypothesis-generating findings warrant prospective validation.

Pancreatic cancer remains a highly lethal malignancy with limited therapeutic options. Chimeric antigen receptor (CAR) therapy has revolutionized the treatment of hematological cancers but still faces major limitations in solid tumors, particularly due to the scarcity of tumor-specific targets. Cutaneous lymphocyte antigen (CLA) recently emerged as a promising PDAC target due to its high tumor expression and limited presence in healthy tissues. However, previously reported CLA-directed CAR constructs lacked antitumor functionality. Here, we investigated multiple strategies to generate functional CLA-targeting CAR approaches. We first hypothesized that impaired activity resulted from fratricide caused by CLA expression on activated T cells. CLA knockout was successfully achieved through deletion of fucosyltransferase-7, but not by knockout of the major CLA carrier backbones CD162, CD44 or CD43, suggesting additional CLA carriers or compensatory regulation. As CLA knockout alone did not restore CAR-mediated killing, we explored whether insufficient binding affinity limited CAR activity. Affinity maturation was performed in silico and in vitro using yeast surface display, identifying 39 candidate mutations, although none restored cytotoxicity. We finally switched to an AdCAR strategy using anti-biotin CAR T cells combined with biotinylated anti-CLA scFv-Fc adapters. This approach enabled efficient, concentration-dependent cytotoxicity with both CLA-targeting binders. Additionally, we identified a dynamic, cell density-dependent regulation of CLA expression. Finally, glycan profiling of CLA binders further revealed broader-than-expected glycan interactions, suggesting a potentially wider definition of the CLA family. Overall, our findings establish CLA as a functional PDAC immunotherapy target while revealing unexpected complexity in its regulation and molecular presentation.

Background: Financial toxicity is an increasingly recognized survivorship issue, but whether diabetes identifies a distinct high-risk financial-toxicity phenotype among U.S. cancer survivors is not well characterized. Methods: We conducted a cross-sectional study using pooled 2021-2024 National Health Interview Survey Sample Adult data. Adults were classified into four mutually exclusive groups: neither cancer nor diabetes, diabetes only, cancer only, and cancer plus diabetes. The primary outcome was any financial toxicity, defined as cost-related care disruption or medication underuse in the prior 12 months. Survey-weighted prevalence estimates and multivariable Poisson regression were used to calculate adjusted prevalence ratios (aPRs). Results: The weighted analytic population included 210.4 million adults with neither condition, 20.6 million with diabetes only, 20.9 million with cancer only, and 4.3 million with both cancer and diabetes. Any financial toxicity was present in 18.8%, 18.8%, 11.6%, and 17.2% of these groups, respectively. Among cancer survivors, diabetes was associated with higher prevalence of any financial toxicity (aPR 1.51, 95% CI 1.33-1.73), inability to afford prescriptions (aPR 1.71, 95% CI 1.40-2.08), skipped medication doses (aPR 1.91, 95% CI 1.48-2.46), any emergency department visit (aPR 1.35, 95% CI 1.24-1.47), and [&ge;]2 emergency department visits (aPR 1.55, 95% CI 1.32-1.83). In treatment-stratified analyses, the burden was greatest among insulin-treated survivors. Conclusions: Cancer survivors with diabetes represent a high-risk financial-toxicity phenotype despite frequent healthcare contact.