bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 449: Catabolism of GSH by GGT supports cancer cell survival
Authors: Zocchi Marco , Hecht Castro Medeiros Fabio , Alimohammadi Fatemeh , Tuttle Emily , Asantewaa Gloria , Scales TashJae , Harris Isaac S. 
Published: March 2024

Abstract
Cancer metabolism depends on amino acid sources to fuel tumor growth and drug resistance. Using amino acid restriction to treat tumors can enhance existing therapeutic techniques. The tripeptide Glutathione (GSH), which contains cysteine, glutamate, and glycine, is often considered an antioxidant, and its potential as an amino acid pool has been overlooked. GSH is ubiquitous in the tumor microenvironment and could provide a ready source of amino acids to tumor cells through its catabolism by the enzyme γ-Glutamyl transpeptidase (GGT), which has been shown to cleave GSH and its’ conjugates in the extracellular space. It is unclear if the cleavage of GSH by GGT supports cancers in vivo. We find that inhibiting GGT with the pharmacologic agent GGsTop blocks GSH catabolism and decreases tumor growth. We show that cultured cells can be rescued from a lethal depletion of cystine upon supplementation with GSH or its catabolic product cysteinylglycine, but not under the conditions of GGT inhibition. Through pharmacokinetic methods, we identify a usable systemic dose of GGsTop and show GGT inhibition in tumor tissue. Further, we demonstrate that systemic GGT inhibition in vivo decreases tumor mass and volume. These findings support the hypothesis that GSH catabolism by GGT1 is a non-canonical source of amino acids for tumor metabolism. Understanding GSH catabolism by GGT could elucidate new metabolic pathways in tumors. Inhibiting GSH catabolism could provide new therapeutic approaches to inhibit tumor growth.
Citation Format: Marco Zocchi, Fabio Hecht Castro Medeiros, Fatemeh Alimohammadi, Emily Tuttle, Gloria Asantewaa, TashJae Scales, Isaac S. Harris. Catabolism of GSH by GGT supports cancer cell survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 449.
Abstract 4534: HSK40495, a highly selective PARP1 inhibitor with improved hematopoietic safety for the treatment of HRD cancers
Authors: Li Fan , Gou Xiaoli , Chen Lei , Meng Qingyuan , Li Yao , Dong Hongjiao , Tang Pingming , Wang Ju , Yan Pangke 
Published: March 2024

Abstract
It is well known that several PARP inhibitors have been approved for tumors with homologous recombination repair deficiencies (HRD), such as BRCA mutations. However, the common side effect of these inhibitors is hematologic toxicity, which limits their therapeutic index and combination potential with first-line chemotherapies. One possible reason is that currently approved PARP inhibitors do not specifically target PARP1, and might also affect other PARP family members. Recent studies have shown that the synthetic lethality caused by PARP trapping with HRD is mainly dependent on PARP1 inhibition, but not other PARP family members. Accordingly, we developed a selective PARP1 inhibitor that effectively inhibits tumor growth with less hematologic toxicity. HSK40495 is a potent PARP1 inhibitor with highly selectivity of PARP2. HSK40495 inhibited PARP1 enzymatic activity with a single digit nanomolar potency and with greater than 5000-fold selectivity against PARP2 in the protein binding assay. In addition, HSK40495 exhibited potent anti-proliferation activity in both DLD1(BRCA KO) cell and MDA-MB-436 cell, while had minimal effects against BRCA-WT DLD1 cell up to 30 µM in an anti-proliferation assay. In a subcutaneous MDA-MB-436 xenograft tumor model, HSK40495 administered orally once daily achieved excellent tumor growth inhibition of 100% at 3mg/kg. HSK40495 demonstrated significant PARylation inhibition in tumor tissues. Importantly, in CD34+ human bone marrow progenitor cell, HSK40495 showed improved cytotoxicity when compare to first-generation PARP inhibitor, Talazoparib. Meanwhile, in a lineage-specific hematotoxicity assay, HSK40495 exhibited improved cytotoxic safety in the process of differentiation of myeloid, erythroid and megakaryocyte compared with Talazoparib treatment. In summary, HSK40495, a highly selective PARP1inhibitor over other PARP family members, exhibits excellent pharmacological and safety properties, and also has the favorable pharmacokinetics profile in preclinical studies. All these findings suggest that HSK40495 has the great potential to be a promising PARP1 inhibitor for further development in the patients with HRD tumors.
Citation Format: Fan Li, Xiaoli Gou, Lei Chen, Qingyuan Meng, Yao Li, Hongjiao Dong, Pingming Tang, Ju Wang, Pangke Yan. HSK40495, a highly selective PARP1 inhibitor with improved hematopoietic safety for the treatment of HRD cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4534.
Abstract 46: Mechanisms and impact of bystander killing by CAR T cells
Authors: Chorazeczewski Joanna , Xie Lishi , Chen Xiufen , Wang Sidney , Kline Justin 
Published: March 2024

Abstract
While CD19-directed chimeric antigen receptor (CAR) T cell therapy has improved outcomes of patients with relapsed/refractory diffuse large B cell lymphoma (r/r DLBCL), a majority will suffer disease relapse following CAR T cell infusion. Therefore, understanding mechanisms of CAR T cell killing is critical to enhance therapeutic efficacy. Cytolysis of CAR T cell targets presumably involves recognition of CD19 antigen by the CAR followed by activation of the granzyme/perforin axis. However, bystander elimination of CD19-negative lymphoma cells by CAR T cells has been reported, indicating that an alternative pathway may be required for optimal killing. Through in-depth phenotyping of a large panel of human DLBCLs and in vitro killing assays, we observed that CD19 expression levels on DLBCL cells and vulnerability to CAR T cell killing were weakly correlated. Conversely, cell surface expression of the death receptor, FAS, on DLBCL cells was strongly associated with susceptibility to CAR T cell killing. Although FAS expression across DLBCL cell lines varied, it could be broadly enhanced following exposure to IFNγ. Potent CAR T cell-mediated cytolysis of CD19-negative, Fas-positive murine DLBCL cells required the presence of CD19-positive lymphoma cells in the culture. CRISPR/Cas9 targeting was employed to delete FAS and/or CD19 in isogenic human DLBCL cells to generate CD19+FAS+, CD19+FAS−, CD19−FAS+, and CD19−FAS− subsets, which enabled us to define the extent to which CD19 engagement by the CAR was required to affect killing via FAS. When CAR T cells were co-cultured with equal numbers of the four gene-modified DLBCL cells described above, CD19+FAS+ DLBCL cells were killed most effectively, followed by CD19+FAS− DLBCL cells, and CD19−FAS+ DLBCL cells. Double-negative DLBCL cells were poorly killed. This result suggested that CD19 engagement by the CAR was required for optimal DLBCL cell killing via FAS, and that CD19 and FAS need not necessarily be engaged on the same target cell. Future studies will determine if Fas/FasL interactions can be exploited by overexpression of FasL in CAR T cells and examination of DLBCL killing in vitro and in vivo.
Citation Format: Joanna Chorazeczewski, Lishi Xie, Xiufen Chen, Sidney Wang, Justin Kline. Mechanisms and impact of bystander killing by CAR T cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 46.
Abstract 4621: Dual targeting as an effective therapeutic strategy for malignant brain tumors
Authors: Magnan Elle Y. , Gourishetti Karthik , Thomas Sydney , Bhere Deepak 
Published: March 2024

Abstract
Glioblastoma, a type of brain cancer known for its aggressive nature and resistance to traditional treatments, remains a significant challenge for the medical community. Despite advances in surgical, radiation, and chemotherapy strategies, patients with glioblastoma typically have a poor prognosis, with a median survival time of only 15 months. While temporary symptom relief may be possible for some patients, complete tumor remission is often not achieved. Given the complexity of this disease, effective treatment options for glioblastoma are highly sought after. In this study, we have evaluated the effectiveness of a combinatorial approach using stem cell-derived exosomes enriched with miR-124 cargo paired with viral oncolysis for treating glioblastoma.
Human Umbilical Cord Stem cells (hUCs) are genetically modified with specific miR plasmids, and then cultivated in a specialized medium that has been depleted of exosomes. The exosomes (exo) that contain the target miR are subsequently extracted, purified, quantified, and characterized. These exosomes are then utilized for all subsequent investigations. Using a combination of cell viability assays and microscopy, the overall effect of the exo-miR-124 and oncolytic virus on both established and patient-derived primary GBM cells is analyzed. Additionally, a time course western blot analysis is conducted to comprehend the molecular mechanisms underlying the effects of the miR modification and viral oncolysis on cell proliferation and death pathways. Orthotopic animal models of GBM will be utilized to assess the effects of miR modulation and viral oncolysis in vivo.
Our research has shown that stem cell-derived exosomes are an effective way to deliver microRNA to specific cells, including tumor cells. This is because they can evade the immune system and target cells directly. Our experiments have shown that combining miR modulation paired with viral oncolysis as a promising approach for treating glioblastoma. Specifically, we have found that miR modulation and viral oncolysis can halt tumor cell proliferation in vitro by targeting multiple pathways involved in GBM growth and progression.
Citation Format: Elle Y. Magnan, Karthik Gourishetti, Sydney Thomas, Deepak Bhere. Dual targeting as an effective therapeutic strategy for malignant brain tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4621.
Abstract 4631: Evaluation of the impact of homozygous MTAP truncations on the activity and selectivity of MTA-cooperative PRMT5 inhibitors
Authors: Tonini Matthew R. , Mignault Andre A. , Whittington Douglas A. , Lombardo Steven A. , Shen Binzhang , Stowe Hannah , Yoda Satoshi , Liu Shangtao , Zhang Minjie , Cottrell Kevin M. , Meier Samuel R. , Rego Heidi , Morawiak Jennifer , Hooper Ellen , Yu Yi , DiBenedetto Heather , Crystal Adam S. , Teng  , Briggs Kimberly 
Published: March 2024

Abstract
Homozygous deletion of the MTAP gene occurs in 10-15% of all human cancers. To benefit this large and diverse patient population, MTA-cooperative PRMT5 inhibitors, including TNG908 and TNG462, have been developed to leverage the synthetic lethal relationship between MTAP deletion and PRMT5 inhibition. MTA-cooperative PRMT5 inhibitors selectively bind the PRMT5-MTA complex driving selective inhibition of PRMT5 in MTAP-deleted cancers while sparing normal, MTAP-proficient cells. Our PRMT5 inhibitors are currently in Phase I/II clinical trials (NCT05275478 and NCT05732831), and eligibility is restricted to patients with tumors with confirmed MTAP loss either detected by next-generation sequencing (NGS) or immunohistochemistry.
MTAP gene loss occurs in cancers because of its chromosomal proximity to one of the most common genetically altered tumor suppressor genes, CDKN2A, but the chromosomal 9p breakpoints for the co-deletion are not uniform. Indeed, while clinical NGS testing and preclinical data confirm that homozygous intragenic MTAP breakpoints occur, the functional consequence of any given breakpoint on MTAP enzymatic activity and protein function remains unknown. Given the potential implications for homozygous intragenic MTAP deletions to impact the clinical response to MTA-cooperative PRMT5 inhibitors, we have started to evaluate the loss-of-function phenotype of various MTAP truncations to determine whether they retain MTAP activity. Here, we present our initial functional genomics analysis of this important diagnostic biomarker using in vitro cDNA reconstitution approaches for MTAP activity combined with analysis of PRMT5 inhibitor sensitivity. Ultimately, these data may help refine patient enrollment on clinical trials to drive the maximum benefit for patients with MTAP-deleted cancers.
Citation Format: Matthew R. Tonini, Andre A. Mignault, Douglas A. Whittington, Steven A. Lombardo, Binzhang Shen, Hannah Stowe, Satoshi Yoda, Shangtao Liu, Minjie Zhang, Kevin M. Cottrell, Samuel R. Meier, Heidi Rego, Jennifer Morawiak, Ellen Hooper, Yi Yu, Heather DiBenedetto, Adam S. Crystal, Teng, Kimberly Briggs. Evaluation of the impact of homozygous MTAP truncations on the activity and selectivity of MTA-cooperative PRMT5 inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4631.
Abstract 4635: RNF208: A novel diagnostic and prognostic biomarker for colorectal cancer and key regulator of malignant behavior
Authors: Guo Fangyue , Zhang Shanfeng , Li Pei 
Published: March 2024

Abstract
Background: RNF208, a member of the RING finger protein family, has been implicated in ubiquitin-mediated degradation of Vimentin, regulating invasion in breast cancer, and serves as a prognostic factor in uveal melanoma. However, its diagnostic and prognostic value in colorectal cancer (CRC), as well as its role in regulating malignant behavior in CRC, remains unclear. This study aims to reveal the potential of RNF208 as a diagnostic and prognostic marker for CRC and its function in regulating malignant behavior in CRC through bioinformatics analysis and experimental validation.
Methods: In this study, based on the ExoRbase2.0 human plasma exosome database (CRC=35; Healthy=118) and TCGA-COAD dataset (CRC=478; Healthy=41), we conducted bioinformatics analysis of the transcriptomic differences in plasma exosomes between CRC patients and normal individuals using ExoRbase2.0. Survival data from the TCGA-COAD dataset were integrated to select key molecules for CRC diagnosis and prognosis. Plasma samples from 39 CRC patients and 16 normal individuals were collected from hospital, and exosomes were isolated and purified using a reagent kit. qPCR was employed to validate the levels of RNF208 in plasma exosomes, confirming the results of bioinformatics analysis. Biological behavior was assessed through CCK-8 proliferation assays, flow cytometry experiments, and Transwell migration assays to investigate the relationship between RNF208 and malignant behavior in the HCT116 colorectal cancer cell line.
Results: Bioinformatics analysis revealed a significant correlation between elevated RNF208 expression in plasma exosomes and the incidence of CRC, as well as poor prognosis. The qPCR results from clinical samples further confirmed this correlation, and ROC curves demonstrated high sensitivity and accuracy, suggesting RNF208's potential as a diagnostic and independent prognostic factor for CRC. CCK-8 experiments showed that RNF208 knockdown suppressed proliferation activity in HCT116 cells, flow cytometry indicated that RNF208 knockdown promoted apoptosis in HCT116 cells, and Transwell migration assays demonstrated that RNF208 knockdown inhibited the migration of HCT116 cells.
Conclusion: RNF208 serves as a novel diagnostic and prognostic biomarker for colorectal cancer, promoting the proliferation and migration of colorectal cancer cells and contributing to the further deterioration of the disease.
Citation Format: Fangyue Guo, Shanfeng Zhang, Pei Li. RNF208: A novel diagnostic and prognostic biomarker for colorectal cancer and key regulator of malignant behavior [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4635.
Abstract 4658: Genome wide CRISPR/Cas9 library screening identifies aurora kinase A as a regulator of elraglusib sensitivity in pancreatic cancer
Authors: Ding Li , Maeder Easton , Zhang Cheng , Weiskittel Taylor , Schmitt Daniel , Mazar Andrew , Li Hu , Billadeau Daniel 
Published: March 2024

Abstract
Pancreatic ductal adenocarcinoma (PDAC) is a deadly malignancy with a dismal 5-year survival rate, highlighting the urgent need to improve drug response and overcome primary or acquired (secondary) resistance to conventional chemotherapy. Glycogen synthase kinase 3β (GSK-3β) is a target in PDAC and the GSK-3 inhibitor, elraglusib, has been shown to improve chemosensitivity of PDAC and survival in preclinical cancer models. In addition, data from phase II clinical trials in patients with previously untreated metastatic pancreatic cancer is demonstrating preliminary evidence of clinical benefit in patients receiving a combination of gemcitabine/nab-paclitaxel. While this early evidence is highly encouraging, the biological determinants of elraglusib response are unknown. Using genome wide CRISPR/Cas9 library screening, we identify aurora kinase A (AURKA), an oncogenic kinase with major roles in mitosis, as a critical regulator for elraglusib sensitivity. Elraglusib treatment activates AURKA by inducing a G2/M cell cycle arrest. We show that knocking out AURKA reduces the phosphorylation of polo like kinase 1 (PLK1), arresting cells in mitosis, and leading to mitotic catastrophe and significant apoptosis after elraglusib treatment. Strikingly, the AURKA inhibitor, alisertib, works synergistically with elraglusib to inhibit PDAC cell line growth and induce apoptosis. In summary, our results demonstrate that targeting AURKA is an effective approach to sensitize PDAC tumors to elraglusib.
Citation Format: Li Ding, Easton Maeder, Cheng Zhang, Taylor Weiskittel, Daniel Schmitt, Andrew Mazar, Hu Li, Daniel Billadeau. Genome wide CRISPR/Cas9 library screening identifies aurora kinase A as a regulator of elraglusib sensitivity in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4658.
Abstract 4695: Effect of fully human anti-PTGFRN antibody drug conjugate on head neck cancer cells and patient derived xenografts
Authors: Marquez Jorge , Dong Jianping , Oshimura Mitsuo , Hayashi Jun , Serrero Ginette 
Published: March 2024

Abstract
Prostaglandin F2 Receptor Negative regulator, or PTGFRN, also known as FPRP is a 175 kDa transmembrane protein associated with metastatic characteristics of certain cancer types and a member of the tetraspanin family. PTGFRN expression is undetectable to low in normal tissues whereas it is elevated in several cancers such as head and neck, mesothelioma and medulloblastoma. PTGFRN has also been reported to be upregulated in many different types of cancer, increasingly so in metastatic cancer cells, compared to their non-metastatic counterparts PTGFRN expression has been reported to be a poor prognostic factor for glioblastoma making it a potential novel cancer therapeutic target. We have previously shown that PTGFRN is an internalizable cell surface protein making it suitable for targeting by antibody drug conjugate (ADC). We have developed fully human monoclonal antibodies to PTGFRN by immunizing humanized transgenic TC mice with human PTGFRN. Within 60 days from the start of immunization we were able to select several fully human anti-PTGFRN monoclonal antibodies that were examined by several functional assays that included flow binding, internalization, affinity determination and cell killing as antibody drug conjugates. Several monoclonal antibodies were selected and evaluated for their ability to inhibit tumor formation in several cancers. Selected antibodies were then conjugated to duocarmycin by a cleavable linker. The present study proposed to examine the effect of one such anti-PTGFRN ADC on head and neck cancer cell lines and patient derived xenografts that had been analyzed for their PTGFRN expression by western blot analysis using anti-PTGFRN antibody. Cells lines and PDX that were positive for PTGFRN expression were used to examine the effect of anti-PTGFRN ADC on their in vitro and in vivo proliferation. The data show that anti-PTGFRN ADC inhibits tumor formation in a dose-dependent fashion. These data also establish PTGFRN as cancer druggable target and the selected fully human anti-PTGFRN antibody as an attractive antibody for the development of new antibody drug conjugate in Oncology. These data also emphasize the potential of humanized transgenic TC mice for the development of fully human monoclonal antibodies, thus bypassing the need for humanization and affinity maturation required by other humanized mice or phase display.
Citation Format: Jorge Marquez, Jianping Dong, Mitsuo Oshimura, Jun Hayashi, Ginette Serrero. Effect of fully human anti-PTGFRN antibody drug conjugate on head neck cancer cells and patient derived xenografts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4695.