Chimeric-antigen receptor (CAR)-T cell therapy has shown early promise against glioblastoma, which lacks effective treatment options. However, two key challenges curtail efficacy: tumor-antigen heterogeneity and an immunosuppressive tumor microenvironment. CAR-T cells engineered to secrete combinations of immunomodulatory proteins can reverse immune suppression and engage endogenous immunity. Through head-to-head in vivo comparisons of potentially synergistic armor combinations, we demonstrated that T cells expressing a CAR plus IL-12 and the decoy-resistant form of IL-18 (CAR-12.DR18 T cells) show strong efficacy against antigen-heterogeneous glioma in immunocompetent mice. Robust anti-tumor efficacy with effective toxicity mitigation was achieved via combined administration of CAR-12.DR18 T cells with CAR-T cells that secrete an anti-vascular endothelial growth factor (VEGF-A) single-chain variable fragment. This combination therapy presents a clinically applicable strategy to overcome key barriers to effective treatment of glioblastoma.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer with poor outcomes. Obesity increases the risk of PDAC through metabolic dysregulation and inflammation. The ketogenic diet (KD) can alter metabolism and has been evaluated for its effects on tumor progression in non-obese PDAC using genetically engineered mouse models (GEMMs). We hypothesized that KD may also prevent obesity-associated PDAC progression by altering body composition and cancer metabolism. Therefore, male PDAC GEMMs were subjected to diet-induced obesity (DIO) using high-fat diets or maintained on a low-fat diet (LFD) for 15 weeks. Mice were then randomized to continue the initial diets or switch to a KD or matched control diet for 6 weeks. Body weight and composition, glucose tolerance, ketone levels, pancreas histology, and tissue metabolomics were assessed. Furthermore, murine pancreas-derived organoids from DIO or LFD fed GEMMs were treated with a ketone body and analyzed using untargeted metabolomics. In obese PDAC GEMMs, KD delayed cancer progression independent of weight loss, an effect not observed in non-obese LFD-fed mice. KD-mediated PDAC suppression was associated with enrichment of pancreatic metabolic pathways that support non-glucose energy production. Ketone-treated organoids recapitulated a subset of the KD-associated metabolic differences observed in vivo, suggesting a direct metabolic effect on cancer cells. These findings suggest potential benefits of a KD in preventing obesity-associated PDAC. The diet-cancer metabolic interactions highlight potential opportunities for dietary or metabolic interventions to prevent PDAC in high-risk obese populations.

Transcriptional intratumoral heterogeneity (ITH) is a hallmark of aggressive cancers. Investigation into the ITH programs that drive tumor metastasis and immune evasion could help identify potential treatment and prevention approaches. Through single-cell RNA sequencing analysis of upper aerodigestive squamous cell carcinoma (UASCC) cells and patient tumors, we uncovered a hybrid epithelial-mesenchymal transition (hEMT) ITH program linked to metastatic dissemination. The transcription factor ETS1 was identified as a master regulator of the hEMT program, directly activating pro-metastatic genes and promoting distant spread in vivo. Unexpectedly, ETS1 also orchestrated an immune-cold tumor microenvironment by transcriptionally activating the STAT1 and CD274 (PD-L1) genes, suppressing T lymphocyte infiltration, and elevating immune checkpoint molecules. Clinically, high ETS1 expression in tumors strongly correlated with poor survival and resistance to immune checkpoint blockade (ICB) across multiple cohorts. Drug screening demonstrated that ETS1-high cancers were vulnerable to HSP90 inhibitors (e.g., alvespimycin), which suppress ETS1 by disrupting HIF1α-mediated transcriptional activation. Together, this work reveals ETS1 as a dual driver of tumor distal metastasis and immune evasion in UASCC, while nominating HSP90 inhibition as a tailored treatment strategy for ETS1-driven tumors. These findings provide a roadmap for targeting aggressive ITH subsets and overcoming immunotherapy resistance.

MYC is amplified on extrachromosomal DNA (ecDNA) or homogeneously staining regions (HSRs) in group 3 medulloblastoma (G3-MB), conferring a poor prognosis. A better understanding of the mechanisms underlying MYC expression in ecDNA and HSRs could be leveraged to develop improved treatments for G3-MB. Using a structure-function approach, we identified and characterized an enhancer (ecMYC E1) that drives MYC activation specifically in G3-MB with MYC-amplified ecDNA or HSRs. The ecMYC E1 locus exhibited enhancer hallmarks exclusively in MYC-amplified G3-MB but not in other MYC-dependent cancer cell lines, including those with MYC amplification. Silencing of the ecMYC E1 enhancer significantly reduced MYC transcription, which was compensated by increases in ecDNA copy number. NeuroD1 and BRD4 interacted with each other and bind to ecMYC E1, looping the enhancer to the MYC promoter. Together, these findings define a mechanism that regulates amplified MYC gene expression within ecDNA or HSRs specifically in G3-MB.

Abstract Cancer arises within a complex cellular milieu, where the extent and composition of tumor-infiltrating immune cells strongly influence tumor progression and patient prognosis. Emerging research highlights the therapeutic potential of fasting mimicking diets (FMDs) in delaying cancer onset, providing cellular protection and regulating immunity. My project investigates immune profiles, before and after the transfer of donor-derived immune cells previously exposed to fasting, either independently or combined with therapeutic drugs. We aim to identify immune populations, enhanced by this combined treatment, and to recognize their impact on tumor advancement and immune activation. Using the syngeneic 4T1, triple negative breast cancer mouse model, we evaluated how fasting and chemotherapy affect tumor growth and immune competence. Flow cytometry and immunohistochemistry were used to characterize immune cells, recruited at tumors, spleens and bone marrows of treated hosts. A subpopulation of preconditioned splenocytes and tumor-infiltrating lymphocytes, recognized through immunophenotyping, were transplanted into tumor-bearing recipients to assess tumor control, immune priming and cytotoxicity. We observed reduced tumor volume, delayed progression and increased survival rate in the transplants exposed to FMD and doxorubicin. The treatment preserved the size, morphology, and cellularity of healthy, primary and secondary lymphoid organs, while expanded beneficial, antitumor immune signatures. Integrating FMD with standard therapeutic strategies could enhance antitumor immunity and broaden the spectrum of malignancies that respond effectively. Exploring the underlying mechanisms may reveal immune pathways that can be therapeutically leveraged to eradicate tumors, in a field that currently remains unexplored. Citation Format: Evangelia Pavlou, Olga Blazevits, Giulia Salvadori, Sara Martone, Valter Longo. Integrating a fasting mimicking diet to augment antitumor immunity following adoptive cell transfer in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(8_Suppl):Abstract nr LB146.

Modifying a single base within the TIGIT gene in NK cells switches inhibitory signaling to an activating axis that enhances antitumor immunity, supporting base editing of immune cells as an immunotherapeutic strategy.

Overabundance of opportunistic pathogens elevates SMOX activity via proinflammatory cytokines to accelerate breast cancer progression, which can be targeted with pharmacological inhibitors of SMOX to significantly inhibit microbiota-associated carcinogenesis.

Topological features of breast cancer histology can be quantified on a continuous scale and used to accurately predict breast cancer patient survival and response to therapy.

The glioblastoma tumor immune microenvironment (TIME) is an immunosuppressive barrier to therapy that encumbers glioblastoma responses to immune checkpoint inhibition (ICI). Immunosuppressive cytokines, pro-tumor macrophages and myeloid cells, and exhausted T-cells are all hallmarks of the glioblastoma TIME. Here we integrate spatial and single-cell analyses of patient-matched human glioblastoma samples before and after ICI with genetic, immunologic, single-cell, and pharmacologic studies in preclinical models to show that interleukin-6 (IL-6) neutralization reprograms the glioblastoma TIME to sensitize mouse glioblastoma allografts to ICI and radiotherapy. We find rare human glioblastomas that achieve clinical responses to ICI have lower pre-treatment IL-6 levels compared to glioblastomas that do not respond to ICI. Our data show that diverse immunostimulatory gene therapies suppress local IL-6 levels in mouse glioblastoma allografts, and that IL-6 from glioblastoma cells and the tumor microenvironment is associated with reduced survival in preclinical models and in patients. We show that IL-6 blockade with a neutralizing antibody transiently sensitizes mouse glioblastoma allografts to ICI by decreasing immunosuppressive Tregs, and by increasing MHCII+ monocytes, CD103+ migratory dendritic cells (DCs), CD11b+ conventional DCs, and effector CD8+ T cells. To translate these findings to a combination treatment strategy that could be used for patients, we show that IL-6 blockade plus ICI more durably sensitizes mouse glioblastoma allografts to immunostimulatory ablative radiotherapy.

Abstract Background: ESR1 mutations (e.g.Y537S and D538G) drive ligand-independent ER activation and resistance in ER-positive breast cancer. (Z)-Endoxifen, the active tamoxifen metabolite, inhibits ER signaling, but its impact on ESR1-mutant signaling and therapy-resistant disease is not yet fully defined. Methods: HEK293T cells were transfected with ESR1-WT or mutant plasmids together with an ERE-luciferase reporter and Renilla control. After 24 h, cells were treated with endoxifen, elacestrant (10 µM-0.01 nM), or 0.1% DMSO for an additional 24 h. Firefly luciferase activity was normalized to Renilla, and mean ± SD values from three independent experiments were used to generate dose-response curves. Transcriptomic analyses of 166 ESR1 Y537S and 45 ESR1-WT MCF-7 samples from PandaOmics were performed, and differential expression after endoxifen treatment was assessed using 27 treated and 25 untreated samples processed with limma and gseapy. Plasma and tumor samples were extracted by methanol precipitation with deuterated endoxifen-d5 and quantified by UPLC-MRM on a Poroshell 120 EC-C18 column using a six-point calibration curve. Results: (Z)-Endoxifen (ENDO) and elacestrant (ELAC) both produced dose-dependent inhibition of ER signaling in wild-type and mutant ESR1 constructs. At 100 nM, ENDO and ELAC showed comparable suppression of WT and three common ESR1 mutants, consistent with the ∼80 nM steady-state ENDO plasma level in women taking 20 mg tamoxifen. At higher doses, ENDO more effectively inhibited Y537S and D538G than ELAC. Transcriptomic analyses revealed that ENDO reversed key mutant-associated transcriptional programs in MCF-7 cells. ENDO significantly downregulated estrogen response, apoptosis, E2F-target, and Myc-target pathways while restoring oxidative phosphorylation, xenobiotic and fatty acid metabolism, p53 signaling, and DNA repair (FDR < 0.05). Transcription factor enrichment showed suppression of resistance-associated POU5F1 and SOX11, and reactivation of FOXA1, ELF3, and SPDEF. ENDO also reduced expression of three genes (MTMR7, IL20, CA12) from a six-gene poor-prognosis ESR1-mutant signature. In the ongoing EVANGELINE phase 2 trial (NCT05607004), mean (Z)-endoxifen plasma levels at 40 mg/day reached 278.5 ng/mL (≈746 nM). Conclusion: In summary, (Z)-endoxifen and elacestrant both suppress ER-dependent transcription in ESR1-WT and mutant models, and clinically relevant (Z)-endoxifen concentrations are sufficient to inhibit mutant ESR1 activity. Endoxifen additionally reprograms key transcriptional and metabolic pathways associated with ESR1-mutant resistance and metastasis. These results support further evaluation of (Z)-endoxifen’s pathway-level effects in ESR1-mutant breast cancer, and ongoing studies are testing its ability to block mutant ESR1-driven proliferation in preclinical models. Citation Format: Sandra Suarez Hammer, Alina Ustiugova, Anastasia Shneyderman, Alexander Veviorskiy, Khadija M. Alawi, Mikhail Korzinkin, Lucia Beaulieu, Hayley Erickson, Scott M. Blackburn, H. Lawrence Remmel, Steven Quay. Mechanistic characterization of (Z)-endoxifen in ESR1-mutant and endocrine-resistant breast cancer [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 1784.