tbuckley/cabot-search huggingface dataset:
Abstract 2942: Efficacy of a claudin 18.2/TGFβ bi-specific CAR-T in preclinical mouse models of gastric cancer
Authors: Ralph F. Fleuranvil, Naryan Rustgi, Michael James, Zachary Hammer, Thomas J. Ryan, Jessica Reyes, Melanie L. Munguiam, Orit Foord, Jiajia Cui, Sandra Ryeom
Journal: Cancer Research (2025)

Abstract Gastric cancer (GC) is one of the 4th leading causes of cancer-related deaths worldwide. For decades, chemotherapy and surgery has been the primary treatment modality, however, the overall five-year survival rate for GC remains at 36% and new therapies are needed. Claudin 18.2, a tight junction protein that is expressed on the GC cell surface, has been validated as a bona fide target in GC with recent FDA approval of zolbetuximab, a Claudin 18.2 directed antibody. Chimeric antigen receptor (CAR)-T cell therapies are human T cells modified to express synthetic engineered receptors designed to target and eliminate cells expressing specific antigens. However, many barriers limit the therapeutic potential of CAR T cells in solid tumors. Our study examined the anti-tumor function of a bispecific Claudin18.2/TGFβ-targeting CAR T-cell candidate in preclinical orthotopic mouse models of GC in an immune competent background, as well as in GC patient-derived organoids (PDO) in an immunodeficient orthotopic mouse model. Our data indicate prolonged tumor suppression in our PDO GC model as well as in our murine gastric tumor-bearing mice treated with Claudin 18.2/TGFβ CAR T cells relative to mice treated with untransduced control T cells. We also demonstrate remodeling of the tumor immune microenvironment in our GC model in an immune competent background with an increase in CD19+ B cells in mice treated with our bispecific Claudin18.2/TGFβ CAR-T versus mice treated with untransduced T cells. Our data suggest that a bi-specific claudin18.2/TGFβ CAR T cell candidate may be an effective therapeutic approach for the treatment of gastric tumors that express Claudin 18.2. Citation Format: Ralph F. Fleuranvil, Naryan Rustgi, Michael James, Zachary Hammer, Thomas J. Ryan, Jessica Reyes, Melanie L. Munguiam, Orit Foord, Jiajia Cui, Sandra Ryeom. Efficacy of a claudin 18.2/TGFβ bi-specific CAR-T in preclinical mouse models of gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2942.
Abstract 5541: Dissecting chemotherapy resistance development in triple negative breast cancer through single cell multiome and lineage tracing
Authors: Chufan Zhang, Chu Pan, Dave Cescon, Mathieu Lupien
Journal: Cancer Research (2025)

Abstract Triple negative breast cancer (TNBC) is a breast cancer subtype that manifests fast disease progression and very poor overall survival. Despite initial response to standard of care, development of therapy resistance remains the major challenge in TNBC clinical management. Delineating the mechanisms underlying resistance development has been impeded by the still unknown cell population of origin and lack of longitudinal molecular profiling. To investigate this question, we applied a CRISPR based lineage tracing system into TNBC cell lines. Longitudinal samples from an Antibody Drug Conjugate (ADC), Sacituzumab Govitican sensitive to resistance were collected in vitro via stepwise drug dose escalation and in vivo via xnenograft serial transplantation. We leveraged cellular barcoding with single cell multiome from 10X genomics to simultaneously capture clonal identity, accessible chromatin and gene expression and hence, directly linked lineage with functional cell states. Preliminary results suggest that TNBC cells adopted distinct cell states shortly after drug exposure with characteristics including upregulation of epithelial-to-mesenchymal transition (EMT) genes, stemness markers and downregulation of immune related pathways. Clonal level analysis revealed only a subset of clones survived initial treatment and are enriched in specific “primed” cell states. Next, we will construct single cell lineage trees and quantify clonal dynamics and cell state transition rates. We will identify and validate regulators of cellular plasticity and explore if potential drug combinations will prevent emergence of resistance cell state. Overall, this study will build a comprehensive map of the phenotypic trajectory towards chemotherapy resistance and pinpoints biomarkers of therapy response in triple negative breast cancer. Citation Format: Chufan Zhang, Chu Pan, Dave Cescon, Mathieu Lupien. Dissecting chemotherapy resistance development in triple negative breast cancer through single cell multiome and lineage tracing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5541.
Abstract 5623: Identification of CGT4255 an EGFR sparing, pan-mutant HER2 clinical development candidate with potential best-in-class brain penetration
Authors: Mark J. Chicarelli, Tanna Bettendorf, Abiezer Blandon, Karyn Bouhana, Richard K. Brizendine, LouAnn Cable, Michelle Crow, Brad Fell, John Fischer, Jennifer Fulton, Anna Guarnieri, Leyla Haygood, Maddie Hillman, Ravi Jalluri, Vijay Kumar, Cori A. Malinky, Rob Rieger, John Robinson, Lee Stunkard, Francis Sullivan, John I. Trujillo, Logan E. Vine, Shannon Winski, Yeyun Zhou
Journal: Cancer Research (2025)

Abstract HER2 alterations such as amplification, overexpression, insertions, and point mutations, are established oncogenic drivers in many solid tumors. Activating HER2 mutations are found in 2-4% of advanced lung cancers and have emerged as mechanisms of acquired resistance to targeted therapies. Patients with HER2 mutant lung tumors develop more brain metastasis during treatment than patients with any other oncogenic drivers in lung cancer. Addressing brain metastasis in this group of patients remains a clinical challenge with limited therapeutic options. Approved HER2 tyrosine kinase inhibitors have inferior potency against key mutations and lack sufficient brain penetration to be an impactful treatment option for patients with brain metastasis. Herein, we describe advanced preclinical profiling of an EGFR-sparing, HER2 inhibitor clinical development candidate CGT4255 with potential best-in-class brain penetrance and potent activity across prevalent point mutations and exon 20 YVMA insertions. CGT4255 demonstrates robust efficacy in intracranial tumor growth inhibition studies and shows an additive effect on intracranial tumor shrinkage when combined with a HER2 ADC. Pre-clinical studies with the CGT4255 and T-DXd combination demonstrate enhancement of ADC internalization, thus highlighting a biological rationale for combination therapy. Citation Format: Mark J. Chicarelli, Tanna Bettendorf, Abiezer Blandon, Karyn Bouhana, Richard K. Brizendine, LouAnn Cable, Michelle Crow, Brad Fell, John Fischer, Jennifer Fulton, Anna Guarnieri, Leyla Haygood, Maddie Hillman, Ravi Jalluri, Vijay Kumar, Cori A. Malinky, Rob Rieger, John Robinson, Lee Stunkard, Francis Sullivan, John I. Trujillo, Logan E. Vine, Shannon Winski, Yeyun Zhou. Identification of CGT4255 an EGFR sparing, pan-mutant HER2 clinical development candidate with potential best-in-class brain penetration [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5623.
Abstract 3181: Single cell characterization and anti-tumor efficacy of single &amp; multi-armored CAR Ts against CLDN18.2
Authors: Megha Sah, Liang He, Gundula Povysil, Cassandra Kontur, Ashley Chui, Stephen Pu, Annie Dyatel, Malavika Sabu, Alice HK Kwon, Xinchen Wang, David Phizicky
Journal: Cancer Research (2025)

Abstract Adoptive cell therapies such as CAR T have struggled to translate to solid tumors due to challenges posed by the solid tumor microenvironment (TME) and the low-throughput of in vivo testing. Pooled CAR T screens are typically restricted to single readouts (e.g. proliferation) and cannot measure the cell-cell and cell-TME interactions that are critical for CAR T success in solid tumors. We performed in vivo spatial pooled screening to profile &amp;gt;250 different CAR T designs to identify efficacious constructs based on spatial-dependent CAR T properties and CAR T-TME interactions. Mouse xenograft models of pancreatic cancer were each injected with hundreds of unique CAR T constructs, including variations in CAR designs and armors. For each library, we prepared 30-40 FFPE slides, harvested from different mice across time points and treated with CAR T cells from different donors. Each slide was stained for 20-30 protein markers, and we also performed in situ genotyping to determine CAR T construct identities in the same microscope images. We obtained image-based phenotypes of ∼20M total single cells and used custom computer vision pipelines to define single cell spatial phenotypes for each CAR T design, including cytotoxicity, exhaustion, local-neighborhood phenotypes, tumor infiltration, on-target/off-tumor toxicity, proliferation, and activity in immunosuppressive tumor regions. We evaluated selected screen hits in single-construct studies, and trained a random forest model with cross-validation to identify the combination of single cell spatial phenotypes for CAR T designs that were most predictive of tumor shrinkage in the efficacy studies. Overall, we identified multiple single- and double-armored constructs that had superior spatial single cell-level phenotypes (e.g. improved infiltration, increased persistence, decreased PD1/LAG3, etc.) compared to both unarmored 2nd gen CLDN18.2 CAR Ts and TGFβRIIDN-armored CLDN18.2 CARs. We then confirmed superior anti-tumor efficacy of these CAR modifications and armors in multiple xenograft models, at multiple doses ranging from 0.5x106 to 2x106 cells. Combinations of these top armors will be further tested in WP-001, a CAR T construct for solid tumors expressing CLDN18.2. Citation Format: Megha Sah, Liang He, Gundula Povysil, Cassandra Kontur, Ashley Chui, Stephen Pu, Annie Dyatel, Malavika Sabu, Alice HK Kwon, Xinchen Wang, David Phizicky. Single cell characterization and anti-tumor efficacy of single &amp; multi-armored CAR Ts against CLDN18.2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3181.
Abstract 1541: Possible role of ectopic ATP synthase mediating metabolic hypoxic adaptation in retinoblastoma
Authors: Samantha A. McLaughlin, Zelia M. Correa, Stefan Kurtenbach, J. William Harbour, Daniel Pelaez
Journal: Cancer Research (2025)

Abstract Altered metabolism is a hallmark of cancer. Yet how metabolic reprogramming benefits tumor growth remains unclear. In retinoblastoma (RB), we have shown that estrogen-related receptor gamma (ESRRG) undergoes continuous positive selection during tumor evolution as evidenced by an ongoing accumulation of genomic aberrations that increase ESRRG activity. Transcriptional analysis revealed that ESRRG is pivotal in mediating metabolic reprogramming, with cells displaying preferential aerobic fermentation and microenvironment acidification. Here, we show that the combination of hypoxic stress and ESRRG deregulation leads to increased ectopic expression of mitochondrial ATP synthase on the plasma membrane, where it is critical to cancer cell proliferation. Translocation of ATP synthase to the plasma membrane was augmented in a time-dependent manner when RB cells were exposed to hypoxia. Pre-treatment of cells with an ESRRG inhibitor eliminated this ATP synthase translocation. Both the F0 proton channel and F1 catalytic domains were identified on the outer plasma membrane by confocal microscopy and flow cytometry. Intracellular ATP concentration, measured by luciferase reaction, was significantly increased by media acidification. Inhibition of lactate/proton export through monocarboxylate transporters resulted in media alkalinization and a significant decrease in intracellular ATP, which could be rescued by subsequent exogenous acidification of the media, suggesting that ectopic ATP synthase uses the proton motive force generated by extracellular acidification to synthesize ATP. A novel F0-targeting ATP synthase inhibitor resulted in near complete cell death of RB cells but showed minimal effect on non-malignant control cells. Interestingly, this drug did not impact the reductive capacity of cancer cell mitochondria compared to control cells, indicating that the drug preferentially affects plasma membrane ATP synthesis at these concentrations. These findings suggest that ATP synthase on the surface of RB cells plays an important role in metabolic adaptation and cell proliferation. These results demonstrate that the use of ATP synthase inhibitors targeting the F0 domain may represent an innovative new strategy to target cancer cells. Citation Format: Samantha A. McLaughlin, Zelia M. Correa, Stefan Kurtenbach, J. William Harbour, Daniel Pelaez. Possible role of ectopic ATP synthase mediating metabolic hypoxic adaptation in retinoblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1541.
Abstract 5447: Development and preclinical evaluation of JK06, a biparatopic ADC against 5T4
Authors: Jonathan McNally, Binyam Bezabeh, Jijun Dong, Samuel Murphy
Journal: Cancer Research (2025)

Abstract Trophoblast glycoprotein, also known as 5T4, is an oncofetal antigen that is upregulated on a variety of solid tumors including breast, lung, and genitourinary cancers. 5T4 expression levels correlate with stage of cancer progression and are associated with poor clinical outcomes. Herein, we describe the pre-clinical design and validation of JK06, a humanized, quadrivalent, biparatopic antibody-drug conjugate (ADC) that targets 5T4, allowing for efficient and selective delivery of a cytotoxic payload, monomethyl auristatin E (MMAE), to tumor cells. JK06 is engineered from 2 monoclonal antibodies (mAbs) that bind to distinct epitopes of 5T4. The first mAb clone was converted to a single-chain fragment variable (ScFv) format and fused to the C-terminal Fc end of a second mAb. This yields a hybrid molecule with four 5T4 binding sites, targeting two distinct epitopes of the 5T4 antigen. This design increases 5T4 avidity, an important feature given the generally low expression of 5T4 on tumor cells and enhances internalization of the drug. JK06 binds to recombinant 5T4 protein with low picomolar affinity measured by surface plasmon resonance, an approximately 10-fold increase in comparison to the two parental mAbs. JK06 induces internalization into 5T4 expressing tumor cells more rapidly and to a greater extent in vitro, than the parental mAbs. The tubulin inhibitor MMAE was conjugated to the Fc backbone of JK06 in a site-specific manner with a cleavable linker at a drug:antibody ratio (DAR) of two. In vivo CDX studies utilizing the MDA-MB-461 breast cancer and H1975 lung cancer cell lines in nude mice demonstrated that JK06 induces robust control of tumor growth in vivo. A repeat-dose GLP toxicology study, with a once every 3-week (Q3W) dosing schedule, demonstrated that JK06 was well tolerated, and without any observed adverse effects at the tested doses. Toxicokinetic evaluation showed a half-life which projects sustained exposure in humans with a Q3W dosing regimen. JK06 is currently being evaluated in an open-label, dose-escalation and expansion Phase I study to assess the safety, pharmacokinetics, and preliminary efficacy in a basket of solid tumors known to express 5T4. Citation Format: Jonathan McNally, Binyam Bezabeh, Jijun Dong, Samuel Murphy. Development and preclinical evaluation of JK06, a biparatopic ADC against 5T4 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5447.
Abstract 5684: PARP inhibitors boost antitumor effects of ADAR1 inhibition regardless of BRCA1 status
Authors: Sophie O'Keefe, Dhillon Parikshak, Marcus Meade, Qiwei Wang
Journal: Cancer Research (2025)

Abstract Triple-negative breast cancer (TNBC), characterized by the absence of estrogen and progesterone receptors and HER2, is the most aggressive form of breast cancer. Despite recent advances in treatment, patients with advanced TNBC continue to face the worst prognostic outcomes among all breast cancer subtypes. In this project, we aim to develop new and more effective therapies for advanced TNBC. Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPis), a class of drugs that target the DNA damage repair response, are the first and only targeted therapy approved for patients with advanced or metastatic TNBC. PARPis are best known for inducing synthetic lethality in tumors deficient in homologous recombination (HR) repair proteins like BRCA1/2. Thus, their approval is limited to BRCA1/2-deficient breast cancer. We and others recently demonstrated that PARPis can also trigger anti-tumor immunity by activating the STING-type I interferon signaling axis (PMID: 30540933, 35641483). However, it remains unclear whether the immunomodulatory role of PARPis can be exploited to expand their use in TNBC. In this study, we found that PARP inhibition increased interferon-stimulated gene (ISG) expression in both BRCA1-deficient and BRCA1-proficient breast cancer cells. This finding is significant because previous studies suggest that cancers with elevated ISG expression are highly reliant on the RNA editing enzyme adenosine deaminase 1 (ADAR1) for survival, making them susceptible to ADAR1 inhibition (ADAR1i). To investigate this further, we utilized tumor cell lines derived from genetically engineered mouse models (GEMMs) of TNBC and employed siRNA, shRNA, and small molecule inhibitors against ADAR1. Notably, we demonstrated that combining PARPi with ADAR1i synergistically killed TNBC cells, regardless of their BRCA status. Taken together, our results highlight the potential of combing PARPis with ADAR1i for treating TNBC, including BRCA-proficient tumors. Citation Format: Sophie O'Keefe, Dhillon Parikshak, Marcus Meade, Qiwei Wang. PARP inhibitors boost antitumor effects of ADAR1 inhibition regardless of BRCA1 status [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5684.
Abstract 4491: HSP70 leverages STUB1 to modulate N-Myc protein turnover in lethal prostate cancer
Authors: Pengfei Xu, Joy C. Yang, Bo Chen, Christopher Nip, Shu Ning, Allen C. Gao, Chengfei Liu
Journal: Cancer Research (2025)

Abstract Background: Imbalances in protein homeostasis (proteostasis) are associated with a wide range of diseases, including neurodegeneration and tumorigenesis. Prostate cancer has proven to be a key model for understanding how proteostasis regulates tumor progression. Neuroendocrine prostate cancer (NEPC) is the most aggressive type of prostate cancer with no effective treatment. The amplification of N-Myc (encoded by MYCN) is a key modification of NEPC. However, it has proven challenging to identify therapeutic strategies that reduce N-Myc transcriptional activity or levels owing to the presence of intrinsically disordered functional domains and lack of enzymatically active sites. In this study, we sought to take a different approach and identify the molecular chaperones involved in N-Myc proteostasis. Methods: N-Myc was knocked down by siRNA. Cell proliferation and N-Myc expression were assessed using cell viability assays and Western blotting, respectively. Rapid immunoprecipitation pull-down assays followed by label-free mass spectrometry were used to identify N-Myc-binding proteins. Co-immunoprecipitation (Co-IP) and Proximity Ligation Assay (PLA) were performed to detect the interaction between HSP70 and STUB1 with N-Myc. In vitro ubiquitination assays were conducted to detect the ubiquitination of N-Myc. Site-directed mutagenesis (SDM) was used to construct N-Myc, STUB1, and ubiquitination deletion or point mutation plasmids. Cycloheximide (CHX) chase assays were employed to examine the half-life of N-Myc. Results: Knockdown of N-Myc by siRNA significantly inhibited the growth of H660, UCDCaP-CR, and CWR22Rv1 cells. A total of 779 proteins were identified as N-Myc-binding proteins. Among them, several HSP70 family proteins, such as HSPA1B (HSP70), HSPA6, and HSPA8 (HSC70), were the most enriched. The HSP70/STUB1 complex interacted with N-Myc and regulated N-Myc protein turnover. This interaction appeared to occur at a degron ‘SELILKR’ in N-Myc. The K416 and K419 of N-Myc seem to be sites for ubiquitination by STUB1, where it added K11-linked polyubiquitin chains for further proteasome degradation. Conclusions: The HSP70 interacts with N-Myc at a conserved binding motif and regulates N-Myc protein turnover through STUB1. Source of Funding: This work was supported in part by grants from National Institutes of Health R37CA249108 (C.L.), R01CA251253 (C.L.), R21CA277171 (C.L.), Department of Defense HT9425-23-1-0144 (C.L.), HT9425-23-1-0325 (C.L.) Citation Format: Pengfei Xu, Joy C. Yang, Bo Chen, Christopher Nip, Shu Ning, Allen C. Gao, Chengfei Liu. HSP70 leverages STUB1 to modulate N-Myc protein turnover in lethal prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4491.