bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 249: Deciphering the impact of TRIB3-ELF4 interaction in regulating CDK6 on cancer stem cell activity in endometrial cancer
Authors: Wang Wen-Ling , Chang Wen-Wei
Published: March 2024

Background: Endometrial cancer (EC) is the most common gynecological tumor among women worldwide, posing a serious threat to women's health. ELF4 (E74 like ETS transcription factor 4), a member of the ETS family, plays a role in facilitating cancer progression. Our previous work demonstrated the role of direct binding between ELF4 and tribbles pseudokinase 3 (TRIB3) in promoting β-catenin expression. In this study, we further explore ELF4's involvement in the maintenance of cancer stem cells (CSCs) in EC.

Methods: The vital role of ELF4 in EC was determined through gain- and loss-of-function assays. ELF4 was silenced in two EC cell lines, AN3CA and HEC-1A, and primary EC cells from a Taiwanese patient (EMC6), using RNA interference techniques. The expression of ELF4, TRIB3, and CDK6 in human EC samples was assessed using immunohistochemistry. Tumorsphere formation assays, quantitative real-time PCR, and immunoblotting quantified CSC activity and the involvement of related signaling pathways. Transcriptional regulation associated with ELF4 was investigated using luciferase reporter assays and chromatin immunoprecipitation.

Results: Analysis of the TCGA database via the TISIDB web tool revealed that elevated ELF4 levels correlated with higher histological grades, advanced clinical stages, and poorer overall survival in EC patients. A grade-dependent increase in ELF4 expression was observed using tissue microarrays. Knockdown of ELF4 in EC cell lines and patient-derived EC cells significantly reduced cell proliferation, cell cycle progression, migration, invasion, and CSC activity. RNA-seq data analysis of ELF4-knockdown EC cells identified CDK6 as a potential downstream target of the ELF4/TRIB3 interaction. Knockdown of ELF4 and TRIB3 significantly downregulated CDK6 expression. Co-expression of TRIB3 and ELF4 enhanced CDK6 expression, and their expression was positively associated with CDK6 in EC specimens. We also demonstrated that CDK6 facilitates EC-CSC activity. Knockdown of CDK6 significantly attenuated tumorsphere formation and reduced the levels of cancer stemness-related proteins, including OCT4, NANOG, and c-MYC.

Conclusion: Our study demonstrates the essential roles of ELF4 and TRIB3 in regulating CDK6 expression, contributing to the maintenance of EC-CSCs.

Citation Format: Wen-Ling Wang, Wen-Wei Chang. Deciphering the impact of TRIB3-ELF4 interaction in regulating CDK6 on cancer stem cell activity in endometrial 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 249.
Abstract 2501: High mutation burden and ultraviolet light signature in conjunctival squamous cell carcinoma
Authors: Esmaeli Bita , Gleber-Netto Frederico O. , Sagiv Oded , Pickering Curtis R. , Gross Neil , Ning Jing , Yeshi Melisachew M. , Mitku Jonas , Tetzlaff Michael T. , Nagarajan Priyadharsini
Published: March 2024

Purpose: Conjunctival squamous cell carcinoma (conjSCC) is endemic in sub-Saharan Africa and is a major cause of ocular morbidity and mortality. This study aims to evaluate Tumor Mutation Burden (TMB), genomic signature, and histologic characteristics of conjunctival squamous cell carcinoma (conjSCC) in two cohorts of patients; one from the USA and one from Ethiopia.

Methods: Whole exome sequencing data, PD-L1 expression, histologic features, and human papillomavirus (HPV) status were analyzed in conj SCC tumors of 25 patients treated at an Ethiopian (ETH) cancer center and 29 patients treated at a US cancer center. Genomic alterations in conjSCC were compared with SCCs from other anatomic sites using data from The Cancer Genome Atlas (TCGA).

Results: TMB was found to be relatively high in conjunctival SCC (3.01/Mb, log10), was comparable to TMB values associated with cutaneous SCC, and was higher than most other SCC types available in the TCGA database. ETH samples had higher tumor mutational burden compared to the US cohort (3.34 vs 2.73). Solar elastosis was seen in a higher percentage of tumors from Ethiopia compared with the US cohort (78% vs. 10%). HPV status was similar between the cohorts (ETH: 21%, MDA: 28%). PD-L1 positivity defined as > 1% of tumor cells was seen in 33 of 53 tumors (62%). Mutations associated with ultraviolet light (UV) signature were the most frequently encountered signatures in both cohorts (SBS7b: 74% and SBS7a: 72%). UV signatures were more prevalent in the ETH cohort compared with the US cohort.

Conclusions: Conjunctival SCC is associated with a high TMB providing the opportunity for immune checkpoint inhibitor therapy for patients with locally advanced and/or metastatic conjunctival SCC. Clinical trials are needed to assess the efficacy of immune checkpoint inhibitors in patients with conjunctival SCC, particularly in sub-Saharan Africa where this cancer is more frequently seen, and is associated with significant morbidity and mortality.

Citation Format: Bita Esmaeli, Frederico O. Gleber-Netto, Oded Sagiv, Curtis R. Pickering, Neil Gross, Jing Ning, Melisachew M. Yeshi, Jonas Mitku, Michael T. Tetzlaff, Priyadharsini Nagarajan. High mutation burden and ultraviolet light signature in conjunctival squamous cell carcinoma [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 2501.
Abstract 2513: MAGE-A3, MAGE-A4, and PD-L1 protein show co-expression in colon, lung and bladder cancer
Authors: Gonzalez Rachel , Guo YiChen , Yom Jina , Gilmore Bailey , Zewdu Eden , Han Xi-Andy , Kong Dehe , Qu Tianli , Ren Qi , Hu Xiaomin , Zhang Ranran , Wu Zhaohui , Strom Alex , Liu Xuan , Fu Wei
Published: March 2024

PD-L1 programmed death ligand 1/CD274 has been shown to be an excellent immune therapy target for many tumors. Currently, studies have shown PD-L1in combination with other immune therapy targets can improve patient outcomes generating the need for new targets. One candidate is the cancer testis antigen Melanoma Antigen Gene Family (MAGE-A) because these genes have limited expression in normal tissues and high expression in cancer. Clinical trials have already begun targeting MAGE-A3 and MAGE-A4 proteins in multiple tumor types. Protein assessment of individual MAGE-A family members has been challenging due to sequence homology as high as ninety-five percent between members. Previously, with the use of CytoSections two highly specific antibodies for immunohistochemistry to MAGE-A3 (clone OTI1H1) and MAGE-A4 (clone OTI2C1) were found. In this study, the MAGE-A3 and MAGE-A4 antibodies were screened with PD-L1 on colon, lung, and bladder cancers. Results show detection of both MAGE-A3 and MAGE-A4 in 25% of colon; 30% of lung; and 20% of bladder cancers. More than 70% of the lung and bladder cancers were positive for MAGE-A4 but only six of twenty-four colon cancers were positive for MAGE-A4. The results show 60 percent of the positive for MAGEA3 or MAGEA4 in colon, lung, and bladder cancers were also positive for PD-L1. This study suggests that MAGE-A3 and MAGE-A4 have tumor specific expression patterns and a potential to be a co-immunotherapy target with PD-L1.

Citation Format: Rachel Gonzalez, YiChen Guo, Jina Yom, Bailey Gilmore, Eden Zewdu, Xi-Andy Han, Dehe Kong, Tianli Qu, Qi Ren, Xiaomin Hu, Ranran Zhang, Zhaohui Wu, Alex Strom, Xuan Liu, Wei Fu. MAGE-A3, MAGE-A4, and PD-L1 protein show co-expression in colon, lung and bladder 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 2513.
Abstract 2521: New predictive markers for dasatinib responsiveness in triple-negative breast cancer: A biomarker discovery study
Authors: Ortega-Álvarez Daniel , Tebar David , Casado Marta , Castillo Elena , Guardia Cristina , Olivares-Osuna David , Musulén Eva , Mereu Elisabetta , Luengo Ginés , Galán-Moya Eva M. , Rodilla Veronica
Published: March 2024

Triple negative breast cancer is the most heterogeneous and aggressive type of breast tumor type and is characterized by the lack of expression of clinical biomarkers (ER, PR, and HER2) and targeted therapies. In this regard, different clinical trials have failed, unable to stratify these patients to find an effective response to specific therapy. This study aimed to identify biomarkers exclusively expressed in the basal mammary compartment that can help us to subclassify the triple-negative breast cancer subtype. Based on computational analysis from single-cell RNA sequencing data, we have identified a list of basal identity-associated genes (BC-markers). Subsequent histological validation confirmed the expression pattern of these markers in a cohort of 50 samples, which has allowed us to stratify triple-negative breast cancer patients into BC-TNBC and luminal-like subtypes. Importantly, the expression of these markers correlated with poorer prognosis in TNBC patients. Functional analysis revealed that TAGLN played a significant role in cell proliferation and migration, potentially impacting tumor aggressiveness. Moreover, the expression of these BC-markers is associated with a mesenchymal phenotype which corresponds to the previously described Lehmannn’s mesenchymal-like signature. In this study, TAGLN appeared to influence dasatinib sensitivity, suggesting its potential as a predictive biomarker for dasatinib response in TNBC patients.

Citation Format: Daniel Ortega-Álvarez, David Tebar, Marta Casado, Elena Castillo, Cristina Guardia, David Olivares-Osuna, Eva Musulén, Elisabetta Mereu, Ginés Luengo, Eva M. Galán-Moya, Veronica Rodilla. New predictive markers for dasatinib responsiveness in triple-negative breast cancer: A biomarker discovery study [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 2521.
Abstract 2541: The landscape of circular extrachromosomal amplification in pediatric cancers
Authors: Sridhar Sunita , Chapman Owen S. , Wang Shanqing , Dutta Aditi , Mesirov Jill P. , Chavez Lukas
Published: March 2024

Circular extrachromosomal DNA (ecDNA, also known as double minutes, dm) has emerged as a driver of oncogenic copy number amplification, intratumoral heterogeneity, tumor evolution and therapy resistance. We recently screened the whole genomes of 481 medulloblatomas for ecDNA and concluded that medulloblastoma tumors harboring ecDNA are more than twice as likely to progress within 5 years of diagnosis. To evaluate the frequency and clincical impact of ecDNA across the spectrum of childhood cancers, we performed a retrospective analysis of 1671 tumors from 1482 patients across 47 pediatric tumor types from two large cloud pediatric cancer genomics resources, the Children’s Brain Tumor Network and St. Jude Cloud. ecDNA was detected in 15 pediatric tumor types, including ETMR (100%, n=4), osteosarcoma (47%, n=57), rhabdomyosarcoma (40%, n=35), neuroblastoma (30%, n=106), high-grade glioma (20%, n=157), and retinoblastoma (19%, n=32). Patients with tumors containing ecDNA had significantly poorer 5-year overall survival. In sequential samples from the same tumor at diagnosis and relapse, we observe evidence of ecDNA evolution including sequence instability and generation of new high-copy ecDNA amplification not detected at initial diagnosis. These results comprise the most detailed survey to date of the landscape of extrachromosomal amplifications across childhood cancers.

Citation Format: Sunita Sridhar, Owen S. Chapman, Shanqing Wang, Aditi Dutta, Jill P. Mesirov, Lukas Chavez. The landscape of circular extrachromosomal amplification in pediatric 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 2541.
Abstract 2588: Bioengineering of site-specific antibody labeling from basic research to spatial omics platforms
Authors: Tao Kai , Rames Matthew J. , Dai MingChong , Sener Gulsu , Olson Samuel , Ranganathan Srivathsan , Ozdemir Sila , Oken Adam , Brasino Michael , Armstrong Randy , Chiu Yu-Jui , Eksi Ece , Branchaud Bruce , Esener Sadik
Published: March 2024

Over the last few years, spatial multi-omics platforms have emerged as a powerful tool for characterizing cancer biology in multiple dimensions. Notably, these systems typically rely on multiplex immunolabeling. Conventionally, multiplexing is accomplished through carefully selecting primary antibodies from different animal species, and in combination with their corresponding polyclonal secondary antibodies. However, given the practical complication related to the species availability of primary antibodies, the multiplexing labeling is still under constraint due to the necessity for matched secondary species labels and the availability. For decades, non-specific labeling of primary antibodies through amine- or thiol-reactive chemistries was widely performed. Evolving research and commercial products have sought to overcome this antibody-based multiplexing limitations by developing enzymatic reaction-directed chemical reaction or antibody targeting proteins that could contain affinity to the Fc or Fab regions of antibodies. However, these methods mentioned above have substantive limitations and side-effects on affinity, conjugation number, buffer incompatibilities, storage incompatibilities, insufficient conjugation, and uncontrolled stoichiometric labeling. Herein, we introduce an efficient, sustainable, reproducible site-specific antibody covalent labeling strategy through engineering anti-IgG secondary nanobodies. These infer the stability, high-affinity of species specific and easy-to-produce IgG binders with the permanence of controlled activation for proximity-driven intermolecular covalent conjugation, with a promise for efficient multiplexity. This labeling technology addresses antibody labeling challenges through currently available approaches, and would substantially enhance multiplexity in a wide variety of research and clinical settings.

Citation Format: Kai Tao, Matthew J. Rames, MingChong Dai, Gulsu Sener, Samuel Olson, Srivathsan Ranganathan, Sila Ozdemir, Adam Oken, Michael Brasino, Randy Armstrong, Yu-Jui Chiu, Ece Eksi, Bruce Branchaud, Sadik Esener. Bioengineering of site-specific antibody labeling from basic research to spatial omics platforms [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 2588.
Abstract 2590: Automating 6-plex chromogenic multiplexing with BOND RX
Authors: Talia Dean , Lindsay Stacey , Ketting Sarah , Williamson Rebecca , Cockfield Damian
Published: March 2024

Multiplex staining using a sequential approach provides a means of visualizing multiple targets in a single biopsy section, further evaluation paired with digital imaging provides a deeper analysis into the spatial relationship at a cellular level. Leica Biosystems enables researchers to complete proof of concept for sequential multiplex staining methods, on board the BOND RX system. Thus, paired with a compatible reagent workflow and a digital slide imaging offering (Aperio GT 450/Aperio AT2) enhances the possibilities for analysis. As with any assay there is a requirement for user optimization, in particular, marker/chromogen layer selection and the pertinent use of an elution step. Such elution step is specifically important within a sequential stain utilizing the same detection reagents on subsequent layers. The results from the multiple staining rounds show a successful 6-plex fully automated stain, possible without the removal and reapplication of the slide onto the BOND system between staining layers. The marker combinations chosen demonstrate compatibility of different host species (Rabbit & Mouse), cellular compartments and isotypes which are provided by Leica Biosystems as BOND Ready to Use reagents. Overall, chromogenic multiplexing provides a stained image which enables color separation, due to the assignment of each chromogen to a marker with an individual cell type and cellular compartment. Finally, the process outlined avoids the risk of signal quenching commonly associated with fluorescent offerings and negates the requirement for specialized equipment due to the enablement of brightfield primary analysis.

Citation Format: Dean Talia, Stacey Lindsay, Sarah Ketting, Rebecca Williamson, Damian Cockfield. Automating 6-plex chromogenic multiplexing with BOND RX [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 2590.
Abstract 2629: N6AMT1-mediated DNA 6mA modification in DNA repetitive elements LINE-1 dynamically regulates the IFN signal pathway in colorectal cancer
Authors: Yuan Ze , Liu Xiaoxia , Wang Xiaolin , Luo Yanxin , Yu Huichuan
Published: March 2024

Background: DNA N6-methyldeoxyadenosine (6mA) modification is the most prevalent DNA modification in prokaryotes, like bacteria, which participates in the host defense system. However, the presence and function of DNA 6mA in eukaryotes remains elusive. Many studies have reported that DNA 6mA modification is distributed across the genome and regulates transcription and the activity of transposable elements, in which the DNA 6mA methyltransferases and demethylases are involved, including the methyltransferase N6AMT1. LINE-1 is a genome-wide DNA repetitive element that acts as a diagnostic and prognostic biomarker for colorectal cancer. Therefore, we aimed to map the DNA 6mA in LINE-1 and investigate its role in the colorectal cancer (CRC) development.

Methods: The restriction-enzyme-digestion assay followed by quantitative PCR (6mA-RE-qPCR) was used to evaluate the LINE-1 DNA 6mA levels in the tumor and normal tissues. The DNA Nanopore sequencing was utilized to determine DNA 6mA and 5mC modifications. After the knockdown of N6AMT1, the dynamic changes of LINE-1 DNA 6mA methylation and RNA transcription under various stresses were determined by 6mA-RE-qPCR and qPCR, and the subsequent RNA-seq was performed to explore the downstream regulated pathways.

Results: The DNA 6mA methylation in LINE-1 is highly variant in the tumor and normal tissues, and it was significantly less prevalent in tumor tissues. The genomic distribution of LINE-1 DNA 6mA is significantly different from that of LINE-1 5mC. The LINE-1 DNA 6mA methylation and RNA transcription levels were dynamically changed in response to various stimuli, including 5-FU and H2O2. Knockdown of N6AMT1 downregulated LINE-1 DNA 6mA methylation and RNA transcription, promoted the proliferation, migration and invasion of CRC cells in vitro, and suppressed the IFN-gamma pathway. The co-culture assay showed N6AMT1 facilitated chemotaxis of macrophages and cytotoxicity of T cells via the IFN-gamma signal pathway.

Conclusions: The heterogeneity of DNA 6mA methylation in LINE-1 and its dynamic change in response to stimuli indicate a biological role of LINE-1 6mA methylation in the primary and adaptive tumor heterogeneities, which provides a novel insight into cancer development. The N6AMT1-mediated DNA 6mA modification in LINE-1 regulates CRC development through the IFN-gamma pathway.

Keywords: N6AMT1, LINE-1, DNA 6mA methylation, colorectal cancer

Citation Format: Ze Yuan, Xiaoxia Liu, Xiaolin Wang, Yanxin Luo, Huichuan Yu. N6AMT1-mediated DNA 6mA modification in DNA repetitive elements LINE-1 dynamically regulates the IFN signal pathway in colorectal 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 2629.
Abstract 2638: Sensitizing immunotherapy-refractory prostate cancer to immune checkpoint blockade therapy with optimized ketogenic diet regimens
Authors: Murphy Sean , Rahmy Sharif , Gan Dailin , Li Jun , Lu Xuemin , Lu Xin
Published: March 2024

The purpose of this study is to investigate strategies for enhancing immune checkpoint blockade (ICB) therapy in prostate cancer (PCa).

To achieve this, we established a series of ICB-resistant PCa cell lines derived from a previously sensitive cell line, which originated from a murine model of metastatic PCa. Notably, we observed a reduction in major histocompatibility complex (MHC) class I protein levels in the resistant sublines.

Our study demonstrated synergistic efficacy through the combination of anti-PD1 and anti-CTLA4 antibodies with histone deacetylase inhibitor (HDACi) vorinostat, a cyclic ketogenic diet (CKD), or β-hydroxybutyrate (BHB) supplementation. Importantly, these interventions significantly delayed PCa tumor progression. Furthermore, our analysis revealed that the effects of these interventions were contingent on both BHB and adaptive immunity. In-depth single-cell transcriptomic and proteomic profiling unveiled mechanisms involving cancer-cell-intrinsic changes (upregulated MHC class I molecules) and extrinsic factors, including CD8+ T cell chemoattraction, M1/M2 macrophage rebalancing, monocyte differentiation toward antigen-presenting cells, and reduced neutrophil presence.

In conclusion, our findings provide valuable insights into the potential clinical utility of combining HDACi and optimized ketogenic diet regimens to enhance ICB therapy for PCa.

Citation Format: Sean Murphy, Sharif Rahmy, Dailin Gan, Jun Li, Xuemin Lu, Xin Lu. Sensitizing immunotherapy-refractory prostate cancer to immune checkpoint blockade therapy with optimized ketogenic diet regimens [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 2638.
Abstract 2655: Unexpected role of the NuRD component, Chd4, in Foxp3+ Treg cells and its relevance to tumor immunotherapy
Authors: Hancock Wayne W. , Wang Liqing , Minisini Martina , di Giorgio Eros , Babic Ivan , Nurmemmedov Elmar
Published: March 2024

We are investigating basic questions like why do Foxp3+ T-regulatory (Treg) cells have at least 3 nuclear complexes involving Hdac1 and Hdac2 (CoREST, Sin3, NuRD), and how can the inhibitory effects of Foxp3+ Tregs on host anti-tumor immune responses be targeted therapeutically? Here, we report on the immune functions of chromodomain-helicase-DNA-binding protein 4 (Chd4), a key enzyme of the nucleosome remodeling and deacetylase complex (NuRD) complex. TCGA analysis showed increased Chd4 expression and Foxp3+ Tregs within lung tumors, leading us to assess the effects of conditional gene deletion within Foxp3+ murine Tregs. Chd4 knockout led to systemic autoimmunity and death of mice within 3 weeks of life and RNAseq studies showed Chd4 loss led to derepression of ~1400 genes and repression of >700 further genes resulting in a Treg signature markedly different from conditional deletion of Hdac1, Hdac2 or Mbd2 in Treg cells. Chd4 is an intrinsically disordered therapeutic target without a defined structure outside its physiological cell environment. To date, no specific inhibitors targeting Chd4 have been developed. We have identified Ch41, a novel and potent inhibitor of Chd4, using a novel cellular target engagement platform. Transcriptomic and mass-spec investigations showed that Ch41 impaired thymic Treg function and iTreg development, led to decreased CNS2 demethylation within the Foxp3 locus, and significantly impaired growth of lung tumors and hepatocellular carcinomas in immunocompetent but not in immunodeficient C57BL/6 mice (p<0.01). Following Chd4 inhibitor therapy, intratumoral conventional T cells had increased activation and cytokine production (IL-2, IFN-g) compared to intratumoral T cells in control tumor-bearing mice but, perhaps unexpectedly, treated mice did not show histologic or biochemical evidence of autoimmunity. We conclude that while tumor associated Tregs have unique properties that include their increased suppressive activity compared to non-tumor associated Treg cells, they are also more susceptible than the latter and conventional T cells to newly developed therapeutic interventions, including targeting of the Chd4 chromodomain of the NuRD complex.

Citation Format: Wayne W. Hancock, Liqing Wang, Martina Minisini, Eros di Giorgio, Ivan Babic, Elmar Nurmemmedov. Unexpected role of the NuRD component, Chd4, in Foxp3+ Treg cells and its relevance to tumor immunotherapy [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 2655.
Abstract 2671: Sustained inhibition of CSF1R signaling effectively augments antitumor immune responses through inhibiting tumor-associated macrophages
Authors: Sato Takahiko , Sugiyama Daisuke , Kojima Yasuhiro , Hattori Satomi , Sone Kazuki , Ishikawa Tomohiro , Ishikawa Yuichi , Kato Takuma , Kiyoi Hitoshi , Nishikawa Hiroyoshi
Published: March 2024

Tumor-associated macrophages (TAMs) are one of the key immunosuppressive components in the tumor microenvironment (TME) and contribute to tumor development, progression, and resistance to cancer immunotherapy. Several reagents targeting TAMs have been tested in preclinical and clinical studies, but they have had limited success. Here, we show that a novel reagent, FF-10101, exhibits a sustained inhibitory effect against colony stimulating factor 1 receptor by forming a covalent bond and reduces immunosuppressive TAMs in the TME, which leads to strong antitumor immunity. In preclinical animal models, FF-10101 treatment significantly reduced immunosuppressive TAMs and increased antitumor TAMs in the TME. In addition, tumor antigen-specific CD8+ T cells were increased; consequently, tumor growth was significantly inhibited. Moreover, combination treatment with an anti-PD-1 antibody and FF-10101 exhibited a far stronger antitumor effect than either treatment alone. In human cancer specimens, FF-10101 treatment reduced PD-L1 expression on TAMs, as observed in animal models. Thus, FF-10101 acts as an immunomodulatory agent that can reduce immunosuppressive TAMs and augment tumor antigen-specific T cell responses, thereby generating an immunostimulatory TME. We propose that FF-10101 is a potential candidate for successful combination cancer immunotherapy with immune checkpoint inhibitors, such as PD-1/PD-L1 blockade.

Citation Format: Takahiko Sato, Daisuke Sugiyama, Yasuhiro Kojima, Satomi Hattori, Kazuki Sone, Tomohiro Ishikawa, Yuichi Ishikawa, Takuma Kato, Hitoshi Kiyoi, Hiroyoshi Nishikawa. Sustained inhibition of CSF1R signaling effectively augments antitumor immune responses through inhibiting tumor-associated macrophages [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 2671.
Abstract 2732: NB203: A Novel therapeutic bispecific antibody targeting CEACAM1/VEGF for tumor immunity and angiogenesis modulation in the tumor microenvironment
Authors: Dong Jinyu , Wang Binbin , Wang Dong , Ni Jie , Bu Tingting , Wang Haojie , Nayak Bishnu , Wang Baiyang , Dong Xin , Zhang Yu
Published: March 2024

The carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1) is detected on leukocytes, epithelia and endothelia, and involved in cell adhesion through homophilic or heterophilic binding. In various gastrointestinal cancers, NSCLC (non-small cell lung cancer), and melanoma, CEACAM1 is highly expressed on tumor cells and tumor stroma, with its levels increasing as the disease progresses. Notably, CEACAM1 has been found to dampen T and NK cell functions while promoting tumor angiogenesis and metastasis. In this study, we present NB203, a novel CEACAM1/VEGF bispecific antibody developed using Neologics CEACAM-plus, a bifunctional molecule engineering platform designed to target and modulate the tumor microenvironment (TME). NB203 effectively accumulated in the TME and hindered the homophilic or heterophilic interactions of CEACAM1. It demonstrated a significant enhancement in T cell activities and NK cell-mediated killing of CEACAM1-expressing tumor cells, and the inhibition of tumor cell migration and polyploidy through macrophages. More importantly, NB203 was specifically designed to impede tumor angiogenesis. It exhibited an increased binding capacity to both CEACAM1 and VEGF in pro-angiogenic TME, and undermined intratumoral vessel maturation by blocking VEGF and negatively regulating myeloid cell-dependent tumor angiogenesis. In summary, our preclinical data indicate that NB203 exhibits effective anti-tumor activity by mediating NK and cytotoxic T cell activities, improving the immune-suppressive TME, and suppressing tumor angiogenesis. The use of NB203 holds promise in overcoming resistance to anti-VEGF therapy and substantially improving the safety of therapeutic targeting of angiogenesis in cancer treatment.

Citation Format: Jinyu Dong, Binbin Wang, Dong Wang, Jie Ni, Tingting Bu, Haojie Wang, Bishnu Nayak, Baiyang Wang, Xin Dong, Yu Zhang. NB203: A Novel therapeutic bispecific antibody targeting CEACAM1/VEGF for tumor immunity and angiogenesis modulation in the tumor microenvironment [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 2732.
Abstract 2782: Characterization of quiescence-associated secretory profile (QuASP) in cancer: A novel defining feature and therapeutic target
Authors: Jiang Qi , Panesso-Gómez Santiago , Natesan Divya , MacDonald Matthew L. , Buckanovich Ronald J.
Published: March 2024

Senescent cells have a unique senescence-associated secretory profile (SASP) and understanding SASP has contributed to numerous advances in knowledge on aging and cancer biology. Quiescence, which is an important yet poorly understood mechanism for chemoresistance, is related but distinct from senescence. Quiescence shares a non-proliferative feature with senescence but is a reversible state in which quiescent cells can reenter the cell cycle. We hypothesized that, analogous to senescent cells, quiescent cells have a distinct quiescence-associated secretory profile (QuASP) and that defining the QuASP will uncover new genes and pathways associated with cancer cell viability and therapeutic resistance. Indeed, suggesting quiescent cells have a unique and biologically important secretome, we found that tumor conditioned medium (TCM) from quiescent ovarian cancer cells (qOvCa) vs. TCM from proliferating cancer cells increased chemoresistance. Similarly, TCM from quiescent cancer cells vs. TCM from proliferating cancer cells suppressed T cell proliferation and INF-gamma/Granzyme B secretion, suggesting a QuASP immunosuppressive effect. RNASeq analysis of qOvCa cells revealed the secreted factor Follistatin (FST) is upregulated in qOvCa and acted as a paracrine pattern to induce chemoresistance. Furthermore, FST was found to be upregulated in peritumoral fluid following chemotherapy and FST levels in patients with OvCa predicted poor prognosis. To identify additional QuASP factors, we used an ER-BIOID labeled system and LC-MS/MS to characterize the secreted proteins from qOvCa induced by serum starvation compared with normal cells in three OvCa cell lines (PT412, PT340, HEY1). Quiescent OvCa cells indeed have a secretome that is highly unique from proliferating cells, with 137/577 upregulated proteins (LFC>1) and 65/577 downregulated proteins (LFC←1 or no detection in quiescence). Several proteins identified as upregulated have been linked to immunosuppression and/or chemoresistance, oncogenesis and cell cycle were selected for validation and further analysis (CLU, VGF, SERPINE1). In conclusion, we find quiescent cells have a unique quiescence associated secretory profile and that the QuASP induces chemoresistance and immunosuppression. As such, this study has important implications for cancer therapy.

Citation Format: Qi Jiang, Santiago Panesso-Gómez, Divya Natesan, Matthew L. MacDonald, Ronald J. Buckanovich. Characterization of quiescence-associated secretory profile (QuASP) in cancer: A novel defining feature and therapeutic target [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 2782.
Abstract 2801: Identifying gut microbial determinants of clonal hematopoiesis of indeterminate potential (CHIP) in immunotherapy treated melanoma patients
Authors: Fallon Eleanor A. , Urrutia Samuel , Ayabe Reed , Chelvanambi Manoj , Damania Ashish , Johnson Sarah , Tanaka Tomoyuki , Li Zongrui , Seo Yongwoo David , Cass Samuel , Wong Matthew C. , Ajami Nadim , Wargo Jennifer , Takahashi Koichi
Published: March 2024

INTRO: Clonal hematopoiesis (CH) of indeterminate potential (CHIP) is associated with poor outcomes in those with non-hematologic cancers. CH mutated macrophages and neutrophils have increased capacity to home to peripheral tissues, driving local inflammation; they are also implicated in immunotherapy related toxicity. The relationship between CH and the microbiome in those treated with immunotherapy is not well understood.

RESULTS: 35 patients with stage IV melanoma treated with upfront immunotherapy; treatment and cohort characteristics are below (Table 1). We performed error corrected duplex sequencing on peripheral blood mononuclear cells using a panel previously validated for CH mutations. With a cutoff of 0.5% variant allele frequency (VAF), among 10 CHIP positive patients, we found mutations in TET2 (8/10), DNMT3A (7/10), PPM1D (2/10), and JAK2 (1/10). There was no difference in either survival or response based on CHIP status (Log-Rank Chi-Square p=0.44); however, CHIP positivity was associated with greater microbiome richness as measured by alpha diversity (p=0.0012 Shannon diversity) and distinct structural/compositional diversity vs CHIP negative patients as measured by beta diversity (p=0.032, R Squared= 0.045). We inferred KEGG pathway activity from whole genome sequencing and identified that CHIP positive patients were enriched for exopolysaccharide biosynthesis while CHIP negative patients had higher expression of nucleotide sugars biosynthesis and amino acid metabolism pathways.

DISCUSSION: In patients treated with immunotherapy for melanoma, microbiome diversity signatures correlate with presence of CHIP. The analysis suggests that there are distinct taxonomic and functional features defining CHIP positivity. The effect of these cells in the tumor microenvironment and their role in immunotherapy response requires further exploration.

Citation Format: Eleanor A. Fallon, Samuel Urrutia, Reed Ayabe, Manoj Chelvanambi, Ashish Damania, Sarah Johnson, Tomoyuki Tanaka, Zongrui Li, Yongwoo David Seo, Samuel Cass, Matthew C. Wong, Nadim Ajami, Jennifer Wargo, Koichi Takahashi. Identifying gut microbial determinants of clonal hematopoiesis of indeterminate potential (CHIP) in immunotherapy treated melanoma patients [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 2801.
Abstract 2817: Establishment of KRAS G12C mutant brain metastasis models for pre-clinical evaluation of KRAS G12C targeted anticancer therapy
Authors: Chen Qikuan , Wang Guilan , Yin Yingfei
Published: March 2024

KRAS is one of the most frequently mutated oncogenes in cancers, especially in lung cancer. Clinical research has shown that about 14% of non-small-cell lung cancers (NSCLCs) carry the KRASG12C mutation, and brain metastases are a relatively common occurrence in KRASG12C-mutated NSCLC. Approximately 30% of patients with KRASG12C mutations develop brain metastases, and those with KRAS-mutated NSCLC and untreated brain metastases have limited treatment options and poor clinical outcomes. AMG510 (Sotorasib) is a small molecule inhibitor of KRASG12C that specifically binds to inactive GDP-bound KRASG12C, preventing its oncogenic signaling. It has been approved for NSCLC by the FDA. Recent clinical studies have shown that Sotorasib exhibits some activity against KRASG12C NSCLC brain metastasis. To evaluate the in vivo activity of AMG510 for NSCLC brain metastasis treatment and provide insights for the preclinical development of new KRAS targeted inhibitors, we established advanced orthotopic models, including intracranial, intracarotid, and intracardiac metastatic models, using the NCI-H358-luc cell line, which harbors the KRASG12C mutation. We validated these models with AMG510 as a single agent or in combination with radiation, which is commonly used in brain tumor therapeutic strategies, to reveal the efficacy and brain concentration of AMG510 in KRASG12C brain metastasis models. Tumor growth and metastasis incidences were assessed using bioluminescence imaging (BLI). All animal studies were performed in an AAALAC accredited facility and aligned with animal welfare regulations. Our preliminary results reveal that AMG510 could penetrate the blood-brain barrier (BBB) and show therapeutic activity for KRASG12C brain metastatic tumors. These models represent powerful tools for clinically relevant assessment of the efficacy of novel KRAS G12C inhibitors and can be expanded for other KRAS mutations-associated brain metastasis or inhibitors.

Citation Format: Qikuan Chen, Guilan Wang, Yingfei Yin. Establishment of KRAS G12C mutant brain metastasis models for pre-clinical evaluation of KRAS G12C targeted anticancer therapy [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 2817.
Abstract 2828: Combining neratinib with trastuzumab deruxtecan to treat HER2;TP53 co-mutated breast cancers
Authors: Cheng Xiaoqing (Cathy) , Highkin Maureen , Hsia Jacob , Prior Julie L. , Hagemann Ian S. , Bose Ron
Published: March 2024

In metastatic breast cancer, HER2 activating mutations frequently co-occur with mutations in the TP53 gene and patients with these two co-occuring mutations have a lower response rate to neratinib. In order to address this clinical problem, we bred HER2 activating mutant transgenic mice with two different alleles of TP53. We used mice with the TP53 R172H mutation, which is the murine homolog of the human hotspot TP53 R175H mutation, and mice with TP53flox/flox allele, which mimics TP53 truncating mutations seen in human breast cancers.

All three H53 genotypes (H53null, H53172/WT, and H53172/null) developed breast cancers faster than H mice, with H53172/null mice developing breast tumors the fastest, at just 6 weeks after adenoviral-Cre injection into the mammary fat pad. We developed organoids from these murine breast cancers and found that all H53 genotype organoids were less sensitive to neratinib compared to H, however, neratinib was able to synergize with trastuzumab deruxtecan (T-DXd), likely through neratinib mediated increased internalization of T-DXd. Prior literature studies suggest TP53 mutant cancer cells may have therapeutic vulnerabilities to the topoisomerase 1 (Top1) inhibitors. Organoids from all three H53 genotypes were sensitive to the Top1 inhibitor, exatecan. H53172/WT behaved like H organoids with G1 phase cell cycle arrest and induction of p21 expression after exatecan treatment. In contrast, H53null and H53172/null failed to induce p21 and arrested at late-S/G2 phase. Additional animal experiments with these H53 genotypes are in progress and results will be presented at the AACR Annual Meeting.

Abbreviation Genotype Median tumor formation (weeks) Neratinib IC50 (nM) Neratinib +T-DXd H HER2V777L 28 10 Not determined H53null HER2V777L;TP53flox/flox 10 240 Synergy H53172/WT HER2V777L;TP53R172H/WT 11 100 Synergy H53172/null HER2V777L;TP53R172H/flox 6 150 Synergy

Citation Format: Xiaoqing (Cathy) Cheng, Maureen Highkin, Jacob Hsia, Julie L. Prior, Ian S. Hagemann, Ron Bose. Combining neratinib with trastuzumab deruxtecan to treat HER2;TP53 co-mutated breast 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 2828.
Abstract 2898: Development of the lipid kinase PIKfyve PROTAC degrader against neuroendocrine prostate cancer
Authors: Qiao Yuanyuan , Li Chungen , Zheng Yang , Jiang Xia , Yee Sarah Nicole , Cheng Caleb , Bao Yi , Zhang Yuping , Wang Yuzhuo , Wang Zhen , Ding Ke , Chinnaiyan Arul
Published: March 2024

Therapies targeting the androgen receptor (AR) as the main driver of prostate cancer (PCa) can lead to various mechanisms of resistance and promote progression to castration-resistant PCa (CRPC), which has a median survival of only 13-23 months. Amongst recurrent CRPC, 17%-30% of patients develop neuroendocrine prostate cancer (NEPC), which is a PCa subtype characterized by a unique histology. NEPC exhibits a loss of AR signaling during neuroendocrine transdifferentiation which results in resistance to AR-targeted therapies and gain of cell characteristics resembling poorly differentiated neuroendocrine tumors. Despite advances in the understanding of NEPC development, treatment options remain limited, with platinum-based chemotherapy as the first-line treatment for both de novo and treatment-induced NEPC. However, response to first-line chemotherapy in NEPC is short, with a median survival of only seven months. The poor prognosis of NEPC is attributed in part to late diagnosis and a lack of effective therapeutic agents. Our previous work demonstrated that NEPC and AR-negative PCa exhibit higher dependency on the lipid kinase PIKfyve than AR-positive CRPC. Thus, development of PIKfyve inhibitory therapies targeting the emergent vulnerabilities of NEPC or AR-negative forms of PCa is a promising approach.

Using a proteolysis targeting chimera (PROTAC) technology, we designed a class of PIKfyve specific degrader. The in vitro degradation efficiency were determined by immunoblotting, and DC50s (degradation concentration at 50%) were calculated for top candidates. Pharmacokinetic and pharmacodynamic were evaluated for in vivo study. In summary, we have developed a class of PIKfyve specific degrader using the E3 ligase von Hippel-Lindau (VHL) as a ligand via a diverse set of linkers. Mechanistic studies revealed that it induced PIKfyve degradation in a VHL- and proteasome-dependent manner.

Citation Format: Yuanyuan Qiao, Chungen Li, Yang Zheng, Xia Jiang, Sarah Nicole Yee, Caleb Cheng, Yi Bao, Yuping Zhang, Yuzhuo Wang, Zhen Wang, Ke Ding, Arul Chinnaiyan. Development of the lipid kinase PIKfyve PROTAC degrader against neuroendocrine prostate 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 2898.
Abstract 2910: Targeting thioredoxin reductase 1 (TrxR1) suppresses TAZ-driven glioblastoma progression
Authors: Tang Miaolu , Dirks Kaitlyn , Kim Soo Yeon , Thorpe Jessica , Li Wei
Published: March 2024

Glioblastoma (GBM) is the most common and aggressive primary brain malignancy in adults. Poor outcomes for traditional treatments demand targeted therapies based on identified mechanisms that drive tumor development and sustain its malignancy. Molecular pathology studies have classified GBM into subtypes differing in treatment responses and survival rates. Among these subtypes, the mesenchymal (MES) group is associated with the worst prognosis. The Hippo pathway transcriptional co-activator with PDZ-binding motif (TAZ) is one of the three transcriptional regulators that drive the GBM MES gene expression program. Studies from our lab and others have previously shown that TAZ activation is able to promote GBM MES differentiation and progression. Therefore, finding vulnerabilities of TAZ-driven tumors may help to develop targeted therapeutic methods for MES GBM. In an orthotopic GBM mouse model, we found that TAZ-driven tumors show increased expression of thioredoxin reductase 1 (TrxR1), which is responsible for catalyzing the reduction of thioredoxin and maintaining the cellular redox balance. In searching for the cause of increased expression of TrxR1, we found that glucose deprivation can induce TrxR1 expression, suggesting TrxR1 may be an adaptive mechanism for tumor cells to survive in glucose deprivation conditions. Indeed, either depleting TrxR1 genetically or inhibiting TrxR1 pharmacologically can promote tumor cell death under glucose deprivation. Furthermore, knockout TrxR1 in a TAZ-driven mouse GBM model significantly decelerated tumor progression. Collectively, our studies revealed that inhibition of the Trx redox system under glucose deprivation conditions leads to a synergistic cell death induction in GBM cells, therefore making targeting TrxR1 a potential therapeutic strategy for TAZ-driven MES GBM.

Citation Format: Miaolu Tang, Kaitlyn Dirks, Soo Yeon Kim, Jessica Thorpe, Wei Li. Targeting thioredoxin reductase 1 (TrxR1) suppresses TAZ-driven glioblastoma progression [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 2910.