BACKGROUND The biological heterogeneity of breast cancer requires robust biomarkers to guide therapy. MicroRNAs (miRNAs) are pivotal post-transcriptional regulators, yet their longitudinal dynamics in matched tissue and plasma during neoadjuvant chemotherapy (NACT) remain poorly defined. AIM To evaluate the prognostic and predictive value of a panel of tumor-suppressive (miR-34a, -124a, -137) and oncogenic (miR-155, -373) miRNAs pre- and post-NACT. METHODS We performed longitudinal profiling of five miRNAs in matched tumor and plasma from 38 patients [27 hormone receptor (HR)-positive; 11 HR-negative]. The study integrated matched tissue-plasma sampling, HR-stratified evaluation, and long-term survival follow-up. Prognostic associations were assessed via multivariate Cox regression, adjusting for age, HR status, and Ki-67. RESULTS High baseline miR-34a and miR-373 independently predicted improved overall survival (P < 0.001). miR-137 was the only miRNA significantly associated with pathological response, showing increased expression in good responders (P = 0.048). While clinical factors, such as older age and HR-positive status, correlated with favorable outcomes, elevated Ki-67 predicted worse overall survival (P = 0.003). NACT significantly modulated profiles, including a shift of miR-124a toward G2 tumors (P = 0.041). Notably, the prognostic value of baseline miRNAs diminished post-treatment, reflecting a convergence of miRNA expression patterns and unstable risk estimates in the post-NACT setting. CONCLUSION Baseline miR-34a and miR-373 are potent prognostic markers, while miR-137 predicts chemosensitivity. Treatment-induced remodeling diminishes the prognostic clarity of post-NACT miRNA landscapes.

Abstract Glioblastoma multiforme (GBM) is the most common primary CNS tumor in adults. Treatment of GBM involves a combination of radiation, chemotherapy, and surgery. Despite significant advancements in radiotherapy, treatment response in GBM remains limited due to challenges such as radioresistance and tumor recurrence. Multiple biological factors contribute to this resistance, including hypoxia, tumor microenvironment interactions, and DNA damage response and repair mechanisms. Previous studies have highlighted the role of integrins in promoting tumor radio resistance under both normoxic and hypoxic conditions. Based on this, we hypothesized that pretreatment of GBM cells with a pan-integrin inhibitor could enhance radiation sensitivity by blocking integrin-mediated pro-survival signaling before radiation-induced stress. In our study, U251 and SNB19 GBM cell lines were treated with GLPG-0187 24 hours before irradiation under both normoxic and hypoxic conditions. CellTiter-Glo (CTG) assays were performed 48 hours post-irradiation, and the combination effects were analyzed using Combenefit software. Under normoxic conditions, pretreatment with GLPG-0187 increased radiation sensitivity in both cell lines. Under hypoxic conditions, pretreatment still enhanced sensitivity, although the effect was attenuated compared to normoxic conditions. Our ongoing studies are expanding these findings to include additional GBM and diffuse intrinsic pontine glioma (DIPG) cell lines and are exploring the molecular pathways affected by this combination treatment. Overall, our results indicate that pan-integrin inhibition prior to radiotherapy could be a promising strategy to improve treatment outcomes in GBM patients. Citation Format: Maryam Ghandali, lanlan Zhou, Wafik S. El-Deiry. Pretreatment with pan-integrin inhibitor GLPG-0187 sensitizes GBM cells to radiation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 4634.

Abstract DNA double-strand break (DSB) repair can be mediated by non-homologous end joining (NHEJ) and homologous recombination (HR). Homologous recombination repair (HRR) is important because it accurately repairs DNA DSBs using a sister chromatid as a template, which is crucial for maintaining genome stability and preventing mutations. Deficiency in HRR makes cancer cells sensitive to DNA damage drugs. BRCA1/2 and RAD51 proteins play very important roles in HRR. PARP is a key enzyme in the repair of DNA single-strand breaks (SSB). Unrepaired SSBs will convert to DSBs in cells. Therefore, BRCA1/2 -mutated cancer cells are sensitive to PARP inhibitors. However, PARP inhibitor resistance develops quickly, mainly through mechanisms that restore homologous recombination repair. This can happen through secondary mutations that restore function in genes of BRCA1 or BRCA2, and overexpression of RAD51. RAD51 overexpression is reported in many cancers, such as breast, prostate, and glioblastoma, and has been involved in chemotherapy resistance. Inhibition of RAD51 creates an HR-deficient status, which can sensitize cancer cells to PARP inhibitor treatments. It has been reported that ISR (integrated stress response) leads to downregulation of RAD51. We reported before that PG3 treatment induced potent ISR. Hence, we hypothesized that PG3 can sensitize PRAP-resistant tumor cells (both BRCA1-mutant and wild-type) to PARP inhibitors by downregulating RAD51. The combination treatments of PG3 and Olaparib/Talazoparib showed synergistic inhibitory effects on triple-negative breast cancer cells, BRCA1-mutated SUM149 and MD-MB-436, and BRCA1-wildtype MD-MB-231 and MD-MB-468. Western blots showed that two BRCA1-mutated cell lines, SUM149 and MD-MB436, express very low levels of BRCA1 protein compared to wild-type cell lines MD-MB231and MD-MB468. On the other hand, SUM149 and MD-MB436 show much higher RAD51 expression than MD-MB231 and MD-MB468. PG3 downregulates RAD51 in both SUM149 and MD-MB231 cells, but not in MD-MB436 and MD-MB468 cells. Transcriptional factors c-Myc, E2F1, and FoxM1 regulate RAD51 gene expression. We found that PG3 induced downregulation of c-Myc, E2F1, and FoxM1 in both SUM149 and MB231 cells, but not in MB436 and MB468 cells. That is consistent with previous publications. PG3 also downregulates wild-type BRCA1 in MD-MB231 cells but not in MD-MB468 cells. We found that olaparib treatment induced upregulation of RAD51 in SUM149 cells and upregulation of both BRCA1 and RAD51 in MD-MB231 cells. PG3 blocked the olaparib-induced upregulation of RAD51 in SUM149cells, and the upregulation of BRCA1 and RAD51 in MD-MB231 cells. The combined treatment induced more DNA damage than olaparib or PG3 alone in SUM149 and MB231 cells, as indicated by increased γH2AX level. Citation Format: Xiaobing Tian, Wafik S. El-Deiry. A combination of PG3 and PARP inhibitors exhibits antitumor effects in both BRCA1-mutated and BRCA1-wild-type TNBC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 1747.

The tumor vasculature is a dynamic and heterogeneous component of the tumor microenvironment (TME) that influences tumor progression, immune infiltration, metastasis, and therapeutic response. This review explores the factors that contribute to the unique vascular characteristics of the TME and highlights the potential for molecular and imaging biomarkers to predict treatment outcomes. We discuss structural and functional abnormalities of tumor vessels, including altered architecture, permeability, interstitial pressure, endothelial phenotype, and impaired drug delivery. We also examine angiogenic signaling through hypoxia-inducible factors (HIFs) and vascular endothelial growth factor (VEGF), in addition to emphasizing non-angiogenic mechanisms such as vessel co-option. The review then turns to the current clinical landscape of angiogenesis, assessing the success and limitations of current therapies, emerging treatment strategies, biomarkers associated with angiogenesis, and AI-assisted prognostication. The establishment and clinical utilization of angiogenesis and tumor vasculature biomarkers is critical for disease diagnosis, prognosis, and the development of targeted therapies. This review ultimately aims to inform future innovation in vasculature-targeted therapies and their personalized clinical implementation to improve cancer care.

e17055 Background: 177 Lu-PSMA-617 ( 177 Lu) radioligand therapy (RLT) is a standard treatment for mCRPC after progression on androgen receptor (AR) pathway inhibitors, with or without prior taxane chemotherapy. Clinical outcomes remain heterogeneous, and predictive genomic biomarkers are lacking. SPOP-mutant prostate cancers exhibit relative genomic stability and preserved AR signaling, which may confer differential sensitivity to PSMA-targeted RLT. We aimed to evaluate the association between SPOP mutations status and treatment outcomes following 177 Lu RLT. Methods: We performed a retrospective analysis of mCRPC patients treated with 177 Lu at a single academic center (2023-2025). Clinical and genomic data were extracted from the EMR. Genomic profiling focused on DNA damage repair (DDR) genes, tumor suppressor genes (TSGs: TP53, RB1, PTEN), and SPOP mutation status. Overall survival (OS) and radiographic progression-free survival (rPFS) were assessed using Kaplan-Meier and Cox proportional hazards models. Results: Among 43 evaluable patients (median age 67 years; 69% Gleason 8-10, 84% received prior taxane therapy), 6 (13.9%) were SPOP-mutant and 37 were wild-type (WT). SPOP mutation was associated with a trend toward improved outcomes, with hazard ratio (HR) 0.20 for OS (p = 0.1) and 0.47 for rPFS (p = 0.1). Identified SPOP mutations clustered within the substrate-binding MATH (Meprin and TRAF Homology) domain, most commonly at known hotspot residues Y87 (n = 3), F102 (n = 1), and F133 (n = 1). Median OS was not reached in SPOP-mutant patients compared with 13.6 months in SPOP-WT patients (log-rank p = 0.09), while median rPFS was 9.0 vs. 5.1 months, respectively (log-rank p = 0.1). SPOP mutation was not significantly associated with baseline clinical, metastatic, genomic, or treatment-related characteristics. In exploratory Cox models with limited adjustment for key clinical variables, the association between SPOP mutation and improved OS (HR range 0.16-0.22) and rPFS (HR range 0.38-0.50) remained directionally consistent. Conclusions: In this real-world cohort of mCRPC patients, SPOP mutation was associated with a consistent trend toward improved survival following 177 Lu therapy. Despite limited numbers of SPOP-mutant cases, these findings suggest that SPOP-mutant mCRPC may represent a biologically distinct subgroup with enhanced sensitivity to PSMA-targeted RLT that is not readily explained by baseline disease burden or treatment history, supporting further investigation in larger, prospective biomarker-driven studies.

Abstract The tumor-suppressor p53 prevents cancer development via initiating cell-cycle arrest, cell death, repair, or antiangiogenesis processes. Over 50% of human cancers harbor cancer-causing mutant p53. p53 mutations not only abrogate its tumor-suppressor function, but also endow mutant p53 with a gain of function (GOF), creating a proto-oncogene that contributes to tumorigenesis, tumor progression, and chemo- or radiotherapy resistance. Thus, targeting mutant p53 to restore a wild-type p53 signaling pathway provides an attractive strategy for cancer therapy. We demonstrate that small-molecule NSC59984 not only restores wild-type p53 signaling, but also depletes mutant p53 GOF. NSC59984 induces mutant p53 protein degradation via MDM2 and the ubiquitin–proteasome pathway. NSC59984 restores wild-type p53 signaling via p73 activation, specifically in mutant p53-expressing colorectal cancer cells. At therapeutic doses, NSC59984 induces p73-dependent cell death in cancer cells with minimal genotoxicity and without evident toxicity toward normal cells. NSC59984 synergizes with CPT11 to induce cell death in mutant p53-expressing colorectal cancer cells and inhibits mutant p53-associated colon tumor xenograft growth in a p73-dependent manner in vivo. We hypothesize that specific targeting of mutant p53 may be essential for anticancer strategies that involve the stimulation of p73 in order to efficiently restore tumor suppression. Taken together, our data identify NSC59984 as a promising lead compound for anticancer therapy that acts by targeting GOF-mutant p53 and stimulates p73 to restore the p53 pathway signaling. Cancer Res; 75(18); 3842–52. ©2015 AACR.

Protease nexin 1 (PN1) is an endogenous serine protease inhibitor (SERPIN), expressed at high levels in the prostate, and capable of inhibiting the proliferation of prostate cancer cells. We previously showed that PN1-uPA complexes inhibited Sonic Hedgehog (SHH) signalling through engagement of the LRP receptor. Here, we describe an alternative anti-proliferative mechanism through which PN1 expression leads to apoptosis. In prostate cancer cells, increased expression of PN1 led to substantial reduction of XIAP levels and apoptosis mediated through the uPAR, but not the LRP receptor. The alterations in XIAP were effected in two ways 1) via alteration in the NF-κB pathway, a pathway known to signal XIAP transcription and 2) by promoting XIAP instability. The AKT pathway is known to phosphorylate XIAP at serine 87 leading to protein stability and PN1 expression is shown to interfere with this process. As a result of both mechanisms, programmed cell death is substantially increased. Consistent with these observations, reduced PN1 protein correlated with elevated p65/XIAP expression and with higher Gleason scores in human prostate tissue arrays. Thus, PN1 expression appears to differentially down-regulate distinct oncogenic pathways depending upon the cell surface receptor engaged by its complexes and demonstrates a novel molecular mechanism by which the protein can promote tumor cell apoptosis.

Abstract Introduction: Small cell lung cancer (SCLC) represents about 15% of all lung cancers, with an estimated 5-year survival rate of only 7%. While most SCLC cases initially respond to chemotherapy, a majority (70-80%) of cases recur and become resistant to first-line treatments. As such, further investigation of novel therapeutics is heavily warranted. Imipridones are a class of selective anti-cancer drugs that activate integrated stress response and increase TRAIL expression to lead to cancer cell death. While ONC201 (dordaviprone) has been investigated in small-cell and various other cancers, its derivatives ONC206 and ONC212 have not yet been explored within SCLC. As such, the present study compares ONC201, ONC206, and ONC212 within the context of SCLC. Methods: Three SCLC cell lines were used: H526, H1048, H1882. For viability assays, cells were plated at 1000 cells/well in a 96-well plate and allowed to adhere overnight before treatment. Viability was assessed 72h after imipridone treatment by Cell-TiterGlo® assay to yield each drug’s IC50. Western Blots (WBs) were performed across cell lines at 24h, 48h, and 72h following equitoxic treatments with each imipridone (IC25, IC50, IC75). Colony formation assays (CFAs) were also performed in triplicate for two cell lines (H1048, H1882) after three-day treatment with equitoxic doses of each drug followed by fourteen days of drug-free incubation. Results: Across cell lines, ONC212 exhibited the lowest IC50, followed by ONC206 and ONC201. By WB, changes in ATF4, cPARP, and ClpX differed by drug, with ONC212 generally inducing the earliest and most significant changes in expression. CFA showed that ONC212 resulted in the greatest decrease in colony formation after 72 hours of treatment, followed by ONC206 and then ONC201. Conclusions: The present findings suggest that SCLC may be highly sensitive to imipridones, particularly ONC212. Future works will aim to explore combination therapies and potential mechanisms including senescence induction, cell cycle alterations that may lead to reproductive arrest, metabolic changes, and alterations in growth and survival pathways in order to further characterize sensitivity and the colony arrest phenotype. Citation Format: Audrey Y. Su, Connor Purcell, Shengliang Zhang, Lanlan Zhou, Ashley S. Uruchurtu, Wafik S. El-Deiry. Imipridones ONC201, ONC206, and ONC212 show potent killing and colony arrest of small-cell lung cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 2937.

Abstract Introduction: MicroRNA 6883-5p (miR-6883) inhibits cancer proliferation and hypoxia signaling by silencing the cyclin-dependent kinases CDK4/6, inducing downstream degradation of Hypoxia-Inducible Factor 1α (HIF1α). Prior work demonstrated that CDK4/6 inhibition (CDK4/6i) induces HIF1α degradation through a VHL-independent mechanism via the E3 ubiquitin ligase SMURF2. Notably, several preclinical studies have reported synergy between CDK4/6i and MEK inhibition (MEKi). Others have reported that CDK4/6i sensitizes cancer cells to ferroptosis inducing agents, though this observation is not unequivocally supported and may be context-dependent. Here, we investigate combinations of miR-6883 lipid nanoparticles (LNPs) with MEKi or ferroptosis inducers using in vitro assays and in vivo murine xenograft models. Methods: A hypoxia response element (HRE)-driven reporter (Addgene #118706) was transduced into HCT116 colorectal carcinoma and SK-BR-3 HER2+ breast cancer (BC) cells. For in vivo experiments, 2 million HCT116-HRE cells were injected subcutaneously into nude mice and tumors ≥150mm3 were treated with 0, 1, or 10µg LNP-encapsulated miRNA. For viability assays, 4,000 cells/well were plated and allowed to adhere overnight. 48-72h after treatment, viability was assessed by CellTiter-Glo®. In vitro hypoxia experiments were conducted in a 0.5% O2 hypoxia workstation. Results: As a single agent, miR-6883 LNPs significantly attenuated HIF signal in the HCT116-HRE xenograft model, with a 94.3% reduction in luminescence observed 3 days post-treatment with 1µg miR-6883 compared to baseline. Ki67 was significantly reduced with a 10µg dose, supporting the antiproliferative activity of miR-6883. In vitro, the SK-BR-3-HRE model demonstrated a significant reduction in HIF activity with miR-6883 treatment under 0.5% O2, suggesting that the anti-hypoxia effect of miR-6883 extends to BC. In vitro viability assays were conducted in HCT116 (colorectal), SK-BR-3 (HER2+), MCF-7 (ER+), MDA-MB-231 (triple-negative), and MDA-MB-468 (triple-negative). Combination of small-molecule CDK4/6i and ferroptosis inducers (RSL3 or erastin) or MEKi (trametinib) revealed largely positive synergy scores. Accordingly, miR-6883 LNPs sensitized cells to doses of RSL3, erastin, or trametinib that were ineffective as monotherapies. Conclusions: Our data support the anti-hypoxia and antiproliferative activity of miR-6883, and provide a basis for combination therapies with ferroptosis inducers or MEKi. Future experiments will employ BC xenografts and assess long-term tumor growth inhibition of combination therapies. Citation Format: Connor Purcell, Leiqing Zhang, Maryam Ghandali, Shulan Holmes-Farley, Audrey Yimin Su, Anais Sidonia, Ameen Raissi, Mackenzie Barrette, Emile Youssef, Theresa M. Raimondo, Wafik S. El-Deiry. Combination of CDK4/6 inhibitory and anti-hypoxia miRNA-6883 lipid nanoparticles with ferroptosis inducers or MEK inhibitors in preclinical breast and colorectal cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3170.

Abstract Small cell lung cancer (SCLC) is an aggressive thoracic malignancy with a 5-year survival rate under 7%. Lack of meaningful improvement of survival rates despite advances in treatment highlights the need for novel therapeutic approaches to improve patient outcomes. Currently, carboplatin + etoposide chemotherapy is the backbone of treatment for most patients. Lurbinectedin is a cytotoxic drug with unique activity against small cell lung cancers in patients with extensive disease and acquired resistance to carboplatin + etoposide. Our preliminary experiments in human SCLC cell lines treated with lurbinectedin demonstrated a dose-dependent increase in Chk1 and Chk2 protein phosphorylation. A consequence of the frequent TP53 inactivation in SCLC is tumor cell reliance on G2/M cell cycle checkpoints involving Chk1/Chk2 to maintain genomic integrity and allow cell survival following DNA damage. We hypothesised that inhibition of Chk1/Chk2-dependent responses with dual-inhibitor prexasertib (ACR-368), would potentiate tumor cell killing by lurbinectedin potentially in a synergistic manner. SCLC cells underwent cell death following single agent prexasertib exposure and this further increased with prexasertib + lurbinectedin combination. Highest Single Agent (HSA) synergy score calculations based on cell viability measurements suggested synergistic action between prexasertib and lurbinectedin at select dose combinations. Western blot analysis of intracellular proteins from SCLC cells treated with both drugs demonstrate dynamic, dose-dependent effects on Chk2, Chk1 and downstream effector Wee1, with lurbinectedin increasing intracellular levels of pChk1 and pChk2, while co-treatment with prexasertib deregulates this process across multiple human-derived cell lines. Synergistic killing was associated with elevated ψ-H2AX levels indicative of DNA double strand breaks and PARP-cleavage due to apoptotic caspase activation. Despite some heterogeneity among treated SCLC cells, the increased phosphorylation of Chk1 was noted at several kinase-activating sites including Serine 296, 317, and 345 while Chk2 Tyrosine 68 phosphorylation was consistently upregulated by lurbinectedin. The results provide a preclinical mechanistic rationale for overcoming a pro-survival, drug resistance-promoting checkpoint pathway to enhance the unique efficacy of single-agent lurbinectedin in patients with SCLC.

Glioblastoma is the most common form of primary brain tumor in adults, characterized by rapid progression and poor prognosis—despite the standard of care treatment including maximal safe resection, radiotherapy, and chemotherapy. Cancer vaccination has emerged as a promising strategy to harness the patient's immune system against glioblastoma. Cancer vaccination strategies can broadly be divided into cell-based or tumor antigen only (TAO), depending on whether they incorporate the use of viable immune cells. Here, we reviewed data from clinical trials that tested TAO cancer vaccination strategies for glioblastoma treatment, including personalized vaccines. Clinical safety and efficacy profiles for each vaccination strategy are summarized. Insights gained from these clinical trials are reviewed to identify opportunities for future therapeutic advancement.

Putative cancer stem cells are a subpopulation of cancer cells that give rise to chemotherapy resistance and are therefore of prognostic and therapeutic interest, though their identification remains elusive in colon cancer due to lack of reliable and accurate markers. We previously identified a p53-dependent putative cancer stem cell population, the calcein low population (CloP), based on their exclusive efflux of the fluorescent dye Calcein. This functional identification method enables comparative live cell studies of subpopulations without differential toxicity that occurs with traditional Hoechst methods, which has confounded conclusions and limited the utility of this cancer stem cell marker. In this study, we examined the cancer stem cell-like properties of the CloP population in vivo in comparison with the parental and calcein-high population (ChiP) in human colon cancer xenografts. Serial dilution xenograft experiments in NOD/SCID mice revealed that the CloP is only marginally more tumorigenic compared to the ChiP or parental cells. However, serial passage of these tumors revealed that the CloP is uniquely enriched for self-renewal capacity in vivo compared to the other populations. Immunohistochemical analysis of these tumors revealed that the CloP possesses increased levels of nuclear β-catenin and furthermore, siRNA-mediated knockdown of β-catenin significantly reduced the CloP population. These findings highlight the CloP as an important subpopulation of tumor cells that are exclusively endowed with the ability to self-renew and propagate tumors. The dependency of the CloP on β-catenin provides a molecular explanation for this ability and suggests that this population can and should be therapeutically targeted by inhibition of Wnt signaling.

This review shares the ongoing work of the global Worldwide Innovative Network (WIN) Consortium for Precision Medicine to synthesize emerging cancer treatment data and to define the requirements for a common global cancer database that can truly support precision oncology. We performed a narrative review of emerging cancer treatment data, molecular profiling technologies, and existing clinicogenomic databases, focusing on how tumors are characterized, how subgroups are defined, and how demographic, lifestyle, and environmental factors are captured. The growth in molecular profiling technologies and the development of new targeted therapies are transforming cancer care. Tumors, regardless of tissue origin, are increasingly defined as composites of multiple, often rare, subgroups, each with distinct biology and likely response to specific therapies, based on multidimensional profiling of the tumor and its microenvironment. The solution lies in building vast databases that capture racial and ethnic diversity, reflected in genomic data, as well as diet and lifestyle factors that may have epigenetic impact on gene expression and post-translational modifications. A truly inclusive and informative data set must reflect global diversity, and there are multiple examples of demography-dependent differences in genomic signals. With members caring for and studying patients with cancer across five continents, WIN is actively exploring pathways to create a global cancer database, rich in clinical and molecular detail, granular enough for precise analysis, and large enough to power artificial intelligence-driven insights, provided appropriate data quality, validation, and governance frameworks are in place. This review surveys the current landscape and outlines practical paths forward to achieve this goal.

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a devastating malignancy with a five-year survival rate of approximately 13%, underscoring the urgent need for novel therapeutic strategies. Next-generation imipridones ONC206 and ONC212 are potent anticancer agents that activate the mitochondrial ClpP protease and the integrated stress response. Lurbinectedin, an FDA-approved therapy for metastatic small cell lung cancer, inhibits transcription by binding the DNA minor groove and has demonstrated preclinical efficacy in PDAC models. Here, we show that ONC206 and ONC212 are highly cytotoxic against PDAC cell lines as monotherapies and in combination with lurbinectedin. Both ONC206 and ONC212 achieved sub-micromolar seventy-two-hour IC₅₀ values in BxPC-3, PANC-1, and HPAF-II PDAC cells, with ONC212 exhibiting greater potency across all lines. Mechanistically, ONC206 and ONC212 induce apoptosis through ClpX depletion, ATF4 induction, and caspase-mediated PARP cleavage. Combination treatment of lurbinectedin with both imipridones produced robust synergy, with ONC212 generally exhibiting stronger synergy at lower concentrations and HSA synergy scores up to 29.5. Importantly, these combinations showed minimal toxicity in CCD 841 CoN non-malignant colon epithelial cells, indicating selective tumor cell killing. Western blot analysis revealed that synergy between lurbinectedin and ONC212 is associated with upregulation of DR5 and downregulation of Bcl-2 and ClpX. These findings provide mechanistic and preclinical support for combining lurbinectedin with next-generation imipridones as a therapeutic strategy in PDAC.

Abstract ONC212 is a fluorinated imipridone with preclinical efficacy against pancreatic and other malignancies. Although mitochondrial protease ClpP was identified as an ONC212-binding target, the mechanism leading to cancer cell death is incompletely understood. We investigated mitochondrial dysfunction and metabolic rewiring triggered by ONC212 in pancreatic cancer, a deadly malignancy with an urgent need for novel therapeutics. We found ClpP is expressed in pancreatic cancer cells and is required for ONC212 cytotoxicity. ClpX, the regulatory binding partner of ClpP, is suppressed upon ONC212 treatment. Immunoblotting and extracellular flux analysis showed ONC212 impairs oxidative phosphorylation (OXPHOS) with decrease in mitochondrial-derived ATP production. Although collapse of mitochondrial function is observed across ONC212-treated cell lines, only OXPHOS-dependent cells undergo apoptosis. Cells relying on glycolysis undergo growth arrest and upregulate glucose catabolism to prevent ERK1/2 inhibition and apoptosis. Glucose restriction or combination with glycolytic inhibitor 2-deoxy-D-glucose synergize with ONC212 and promote apoptosis in vitro and in vivo. Thus, ONC212 is a novel mitocan targeting oxidative metabolism in pancreatic cancer, leading to different cellular outcomes based on divergent metabolic programs.

p53-dependent apoptosis is a major determinant of its tumor suppressor activity and can be triggered by hypoxia. No p53 target is known to be induced by p53 or to mediate p53-dependent apoptosis during hypoxia. We report that p53 can directly upregulate expression of Bnip3L, a cell death inducer. During hypoxia, Bnip3L is highly induced in wild-type p53-expressing cells, in part due to increased recruitment of p53 and CBP to Bnip3L. Apoptosis is reduced in hypoxia-exposed cells with functional p53 following Bnip3L knockdown. In vivo, Bnip3L knockdown promotes tumorigenicity of wild-type versus mutant p53-expressing tumors. Thus, Bnip3L, capable of attenuating tumorigenicity, mediates p53-dependent apoptosis under hypoxia, which provides a novel understanding of p53 in tumor suppression.

Abstract Background: Cytomegalovirus (CMV) has been implicated in glioblastoma (GBM) pathogenesis by promoting stemness, angiogenesis&immune evasion. Clinical trials targeting CMV in GBM have shown preliminary promise, However, the molecular mechanisms remain unclear. We hypothesized that CMV enhances oncogenic signaling and immune resistance in GBM, and that antiviral therapy may reverse these effects and increase susceptibility to immune-mediated cytotoxicity Materials and Methods: Human GBM cell lines (U251, U87, U138, T98G, LN229) & normal astrocytes were infected with a mCherry-human CMV TB40 strain (MOI 0.5). Phenotypic assays including spheroid & colony formation were performed. A 60-plex cytokine panel and Western blotting were used to evaluate cytokine profiles & signaling pathway activation (IL-6/STAT3, Akt, SOX2, Survivin, p-RB). Co-culture experiments with NK-92mi cells were conducted using CMFDA and Eth-homodimer dyes to assess cytotoxicity. Results: CMV infection upregulated IL-6/STAT3, SOX2, Survivin, p-AKT, and p-RB, promoting GBM cell proliferation, stemness, and resistance to apoptosis. Infected cells exhibited a tumor-supportive cytokine profile and, after ganciclovir treatment, reduced VEGF and Angiopoietin-2 levels. CMV-infected astrocytes also showed increased oncogenic signaling and colony formation, suggesting a role in early transformation. Ganciclovir partially reversed these effects, shifting cytokine expression toward an immune-permissive state. While NK cells alone failed to lyse GBM cells, ganciclovir-treated, CMV-infected cells showed significantly enhanced NK-mediated cytotoxicity. PD-L1 expression increased after CMV infection and remained elevated post-treatment, indicating immune modulation and potential for checkpoint blockade. Conclusions: CMV infection reprograms both glioblastoma cells and normal astrocytes toward a more aggressive, immune-evasive phenotype through activation of IL-6/STAT3, p-AKT, SOX2, and angiogenic pathways. Ganciclovir treatment partially reverses these effects, reducing VEGF and Angiopoietin-2 levels, shifting cytokine profiles, and—critically—enhancing NK cell-mediated cytotoxicity. Persistent PD-L1 upregulation following infection suggests a novel immune checkpoint vulnerability, opening the door for synergistic antiviral and immunotherapy approaches. These findings identify CMV not only as a driver of tumor progression but as a tractable therapeutic target in GBM. Citation Format: Vida Tajiknia, Wafik S. El-Deiry, Connor Purcell, Sean E. Lawler. Antiviral therapy reverses CMV-induced oncogenic signaling and enhances NK cell cytotoxicity in glioblastoma with associated PD-L1 upregulation and iImmune modulation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 7410.

Renal cell carcinoma (RCC) is among the top ten most common cancers diagnosed in the United States. The incidence of RCC has continued to increase in recent years, yet our understanding of its etiology is incomplete. Clear cell RCC (ccRCC) is the major subtype, constituting over 75% of all RCC cases. Treatment options for RCC are limited in efficacy, as RCC tumors typically acquire resistance to current therapies, particularly in advanced and metastatic RCC. von Hippel-Lindeau (VHL) status is the only clinically validated biomarker approved for therapeutic intervention in RCC to date. The identification of novel molecular targets is therefore critical for improving therapeutic strategies for RCC. PIM1 is a constitutively active serine/threonine kinase involved in promoting proliferation, invasion, migration, and apoptosis evasion in cancer. PIM1 expression is dysregulated in ccRCC, contributing to oncogenesis and tumor progression. Here, we explore the influence of PIM1 expression in real-world outcomes of patients with RCC. We identify a link between IL-6 expression and PIM1 expression and activity in human ccRCC tumors and cell lines. Our work provides evidence that targeting an IL-6/JAK/STAT/PIM1 axis may be a viable therapeutic strategy for patients with PIM1-high expressing ccRCC.