bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1440: Retinoblastoma binding protein 9 regulates intestinal inflammation and inflammation-associated carcinogenesis
Authors: Nakanishi Yuki , Hamada Kensuke , Omatsu Mayuki , Iwane Kosuke , Kitamoto Hiroki , Okabe Maokoto , Muta Yu , Yamamoto Shuji , Fukuda Akihisa , Kasashima Hiroaki , Seno Hiroshi
Published: March 2024

The intestinal epithelium constitutes the mucosal barrier, and its dysfunction promotes microbial invasion from the gut lumen, which further induces the intestinal inflammation. Chronic intestinal inflammation, as observed in poorly controlled inflammatory bowel diseases (IBD), leads to the development of inflammation-associated cancer. Thus, a deeper understanding of the regulatory system that controls intestinal homeostasis is essential. Retinoblastoma-binding protein 9 (RBBP9) is expressed in a range of human cancer cells. RBBP9 was initially reported to have the ability to regulate the cell cycle pathway. More recent studies have identified RBBP9 as a serine hydrolase (SH) that promotes cancer progression by subverting the anti-proliferative function of TGFβ in a pancreatic cancer model. However, little is known about the roles RBBP9 plays in the development of intestinal cancer. In this study, we investigated the role of RBBP9 in inflammation and inflammation-associated cancer in the intestine. Analyses of surgically resected human samples and publicly available datasets demonstrated that RBBP9 expression was reduced in patient samples of ulcerative colitis (UC) and colitis-associated cancer (CAC). Genetically knockout mice for Rbbp9 (Rbbp9−/−) were susceptible to experimental colitis induced by dextran sulfate sodium (DSS). Furthermore, Rbbp9−/− mice exhibited enhanced azoxymethane/DSS-induced tumorigenesis, a model for human CAC. Mechanistically, RNA sequencing of these tumors showed increased enrichment of inflammation-associated signatures, including interferon signaling pathways. Ex vivo organoid experiments revealed the suppressive function of RBBP9 in interferon signaling-mediated apoptosis of the intestinal epithelium. Simultaneous inhibition of RBBP9 and STAT1, a downstream transcription factor of interferon signaling, reverted the apoptotic phenotype of Rbbp9−/− organoids. Collectively, our data provide insight into the understanding of the crucial role of RBBP9 in protecting against intestinal inflammation and inflammation-related tumorigenesis via regulating the interferon signaling-mediated apoptotic pathway.

Citation Format: Yuki Nakanishi, Kensuke Hamada, Mayuki Omatsu, Kosuke Iwane, Hiroki Kitamoto, Maokoto Okabe, Yu Muta, Shuji Yamamoto, Akihisa Fukuda, Hiroaki Kasashima, Hiroshi Seno. Retinoblastoma binding protein 9 regulates intestinal inflammation and inflammation-associated carcinogenesis [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 1440.
Abstract 1489: The role of EPAS1 and TEAD1 in gastric cancer liver metastasis
Authors: Lee DONG KI , Park Hyun Woo , Cheong Jae-Ho , Gee Heon Yung
Published: March 2024

Gastric cancer ranks fifth in incidence and fourth for cancer-related mortality worldwide. While the liver is widely recognized as the leading site of metastasis in gastric cancer, the intricate mechanisms underpinning its tropism toward the liver and the hematogenous metastasis process remain poorly understood and demand further investigation.

Hematogenous metastasis encompasses the generation of circulating tumor cells from the primary tumor site and their subsequent attachment to the metastatic niche. This process involves the transition between adherent and suspension states. In our investigation of anchorage dependency, we identified 20 transcription factors upregulated in suspension cells compared to adherent cells and 18 transcription factors upregulated in adherent cells relative to suspension cells, respectively.

To investigate factors involved in gastric cancer metastasis, RNA sequencing of paired primary and metastatic tissue samples obtained from 15 patients diagnosed with advanced gastric cancer was conducted, which disclosed the selective upregulation of EPAS1 and TEAD1 in metastatic liver tissue compared to the matched primary tumor tissue and the metastatic tissue originating from other sites.

Through in vitro analysis, we observed a portion of adherent cells transitioning into suspension cells when subjected to a hyperdense environment. We also observed cell reattachment upon harvesting and replating these suspension-state transited cells. Comparing EPAS1 and TEAD1 expression in these states unveiled increased expression of EPAS1 and TEAD1 in reattached cells relative to suspension-state cells.

We established a gastric cancer metastasis mouse model introducing gastric cancer cells into the mouse circulatory system via intracardiac injection to validate our findings. In vivo imaging was utilized to confirm systemic metastasis. After fluorescence-based cell sorting, EPAS1 and TEAD1 expression in cancer cells collected from the blood, liver, and ovary were assessed. We detected higher expression of EPAS1 and TEAD1 in liver metastasis compared to the circulating tumor cells. Furthermore, EPAS1 and TEAD1 were upregulated in liver metastatic cancer cells compared to ovarian metastatic cancer cells.

Our findings underscore EPAS1 and TEAD1 as pivotal factors governing gastric cancer liver tropism and metastasis, offering insights that may contribute to targeted interventions in the clinical landscape.

Citation Format: DONG KI Lee, Hyun Woo Park, Jae-Ho Cheong, Heon Yung Gee. The role of EPAS1 and TEAD1 in gastric cancer liver metastasis [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 1489.
Abstract 1522: Tumor-associated fibrosis leads to an increase in T-cell exhaustion and impairs tumor control in non-small cell lung cancer
Authors: Panni Usman Y. , Shenoy Varun , Knolhoff Brett , Ahmed Faiz , Herzog Brett , Hawkins William G. , Olson John A. , DeNardo David G.
Published: March 2024

Lung cancer is the leading cause of cancer-related mortality with non-small cell lung cancer (NSCLC) being the most predominant type. Recent studies have shown the efficacy of anti-PD1 inhibitors which improved overall survival. However, this efficacy is limited to a subset of patients due to the intrinsic tumor resistance to immune checkpoint inhibitors. Our group recently demonstrated that tumor-associated fibrosis negatively correlates with T cell-mediated immune response in lung cancer. This is largely dependent on Col13a1-expressing cancer-associated fibroblasts (CAFs), which result in recruiting the immunosuppressive macrophages and regulatory T cells while limiting dendritic cells and CD8 T cell infiltration. Here, we characterize the effect of fibrosis on the TME including TILs and macrophages using an orthotopic KRAS and P53-driven murine NSCLC model (KPL86-mCher model) with FITC-induced fibrosis.Fibrosis significantly increased the number of cancer-associated fibroblasts and collagen density in KPL86-mCher lung tumors. Following carboplatin + pemetrexed and Anti-PD1 treatment, we observed no increase in tumor-infiltrating CD4+ and CD8+ T cells or decrease in tumor burden when compared with the non-fibrotic tumors. Rather, we observed a significant increase in exhausted T cells marked by high Tim3, PD1, and TOX in fibrotic KPL86-mCher tumors. Corresponding to these impaired T-cell responses, we found an increase in tumor-infiltrating alveolar macrophages with immunosuppressive phenotype under fibrotic tumor conditions. Our data suggests that tumor-associated fibrosis leads to an increase in CD8+ T cell exhaustion as well as immunosuppressive macrophage infiltration in our spontaneously derived murine model on NSCLC. Overall, this indicates that targeting tumor fibrosis may significantly improve the efficacy of immunotherapy which would have translational implications for patients with immunotherapy-resistant NSCLC.

Citation Format: Usman Y. Panni, Varun Shenoy, Brett Knolhoff, Faiz Ahmed, Brett Herzog, William G. Hawkins, John A. Olson, David G. DeNardo. Tumor-associated fibrosis leads to an increase in T-cell exhaustion and impairs tumor control in non-small cell lung 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 1522.
Abstract 1538: Impact of C-reactive protein on the efficacy of immune checkpoint inhibitors in non-small cell lung cancer
Authors: Li Wenyuan , Guo Hui
Published: March 2024

Background: Immune checkpoint inhibitors (ICIs) therapy has achieved remarkable success in the treatment of non-small cell lung cancer (NSCLC). Clinical studies have suggested a correlation between C-reactive protein (CRP) levels and treatment efficacy, but it remains unclear whether CRP can directly impact the efficacy. Therefore, we investigated the imapct of CRP on the efficacy of ICIs in NSCLC.

Methods: The tumor growth model was established in CRP knockout and wildtype mice by injecting LLC cells to evaluate the effect of CRP on tumor proliferation. The frequencies and phenotypes of macrophages and T cells in mouse tumors were detected by flow cytometry. The impact of CRP on macrophage polarization was evaluated using flow cytometry and IF, while its impact on T cell chemokines CCL5, CXCL9, and CXCL10 was analyzed by ELISA and qRT-PCR. mCRP and α-PD-1 were implemented in C57/BL6 mice injected with LLC cells to evaluate the effect of mCRP on tumor immunotherapy. The frequencies of T cells in mouse tumors were detected by flow cytometry. Expression of mCRP and infiltration of immune cells in human NSCLC tissues were analyzed using IHC.

Results: We found that tumor progression was enhanced and the proportion of tumor-infiltrated M1 macrophages was decreased in CRP knockout mice. Using human PBMC-derived macrophage and RAW264.7 cell lines, we demonstrated that the monomeric form of CRP, known as mCRP, induced M1 polarization of macrophages, leading to increased secretion of CCL5, CXCL9, and CXCL10. In tumor bearing mice, mCRP treatment enhanced anti-tumor immunity and suppressed tumor progression by increasing CD4+ and CD8+ T cell recruitment. Surprisingly, the combined treatment of mCRP and α-PD-1 induced more significant tumor regression than α-PD-1 treatment alone. Additionally, high level of mCRP in NSCLC tissues is correlated with a more inflamed tumor microenvironment phenotype.

Conclusion: mCRP can enhance the efficacy of immune checkpoint inhibitors in NSCLC by activating anti-tumor immunity.

Citation Format: Wenyuan Li, Hui Guo. Impact of C-reactive protein on the efficacy of immune checkpoint inhibitors in non-small cell lung 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 1538.
Abstract 1576: The heterogeneity between pancreatic ductal adenocarcinoma with & without lymphovascular invasion
Authors: Zou Yiping , Xie Yongjie , Gao Song , Zhou Tianxing , Yu Jun , Hao Jihui
Published: March 2024

Background Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest malignant solid tumors, with a five-year survival rate less than 10%. Lymphovascular invasion (LVI) is a poor prognostic indicator for PDAC, yet the difference between tumors with or without LVI is unclear.

Methods We used scRNA-seq analysis on the PDAC tissue of 24 patients obtained from the National Genomics Data Center (Project number: PRJCA001063) to compare T-cell, macrophage, & cancer-associated fibroblast (CAF) heterogeneity between LVI-positive & LVI-negative PDAC. To validate the scRNA-seq results, complementary techniques, including multiple immunofluorescence assays & flow cytometry, were used. Additionally, we analyzed the characteristics of LVI-positive PDAC tumor cells.

Results LVI-positive PDAC thrives in an immunosuppressive microenvironment. We discovered that CD8+ T cells were more deficient in LVI-positive PDAC than in LVI-negative PDAC. Furthermore, the effective & cytotoxic markers (such as GZMB & IFN-γ) of CD8+ T cells also decreased in LVI-positive PDAC. M2 macrophage polarization was found to be higher in LVI-positive PDAC compared to LVI-negative PDAC. In addition, we discovered a more fibrotic TME signature in LVI-positive PDAC. LVI-positive tumor cells, in particular, had a mesenchymal transition phenotype & a hypoxic microenvironment.

Conclusions This study adds to our understanding of the intricate heterogeneity seen in LVI-positive PDAC. It sheds light on the distinct characteristics of LVI-positive PDAC & advances our understanding of its underlying biology.

Citation Format: Yiping Zou, Yongjie Xie, Song Gao, Tianxing Zhou, Jun Yu, Jihui Hao. The heterogeneity between pancreatic ductal adenocarcinoma with & without lymphovascular invasion [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 1576.
Abstract 1589: Integrated multiomics analysis revealed the significance of Transgelin in driving pancreatic cancer-associated fibroblast-mediated cancer progression
Authors: Shinjo Keiko , Wang Xingxing , Kumegawa Kohei , Maruyama Reo , Mii Shinji , Murofushi Yoshiteru , Suzuki Miho , Enomoto Atsushi , Kondo Yutaka
Published: March 2024

Pancreatic ductal adenocarcinoma (PDAC) is primarily characterized by a desmoplastic reaction, mainly consisting of cancer-associated fibroblasts (CAFs). In order to investigate the heterogeneity of CAFs, we initially conducted single-cell Assay for Transposase-Accessible Chromatin with high-throughput sequencing (scATAC-seq) using pancreas tissue from 12-week-old KPC (K-rasLSL.G12D/+; Trp53R172H/+; Pdx-1-Cre) PDAC mouse models. We identified three clusters enriched with myofibroblast CAF (myCAF) gene markers and one cluster enriched with inflammatory CAF (iCAF) gene markers. Next, we performed single-cell RNA sequencing (scRNA-seq) on pancreas tissues from KPC mice. scRNA-seq revealed four distinct fibroblast clusters, each exhibiting characteristic gene expression profiles of normal fibroblasts, iCAF, myCAF and antigen-presenting CAF (apCAF). These findings suggest that CAFs in the myCAF cluster identified in scATAC-seq may have potential to differentiate into either myCAFs or other CAF subtypes based on certain cues. Next, we focus on the expression of myCAF marker genes, particularly two commonly used markers, Tagln and Acta2. Among myCAFs, two subtypes were identified: Tagln-positive and Acta2-positive CAFs, and Tagln-negative and Acta2-positive CAFs. To confirm our findings, we conducted Immunohistochemical analysis (IHC) on KPC pancreas samples. We observed CAFs that were positive for both Talng and αSMA exclusively in close proximity to tumor cells. Fibroblast expressing only αSMA mostly located in normal area. Tagln is known as an actin-binding protein and plays an important role in activated fibroblasts. Orthotopic PDAC mouse models using Tagln homozygous knockout mice showed a significant reduction in tumor weight compared to the wild-type mice (P = 0.0076). Indeed, we found that high TAGLN expression in PDAC samples was associated with poor survival, as demonstrated by the analysis of the TCGA dataset. These data suggest that myCAFs expressing TAGLN contribute to the promotion of PDAC growth. Targeting stromal TAGLN might be a potential therapeutic strategy to counteract PDAC progression.

Citation Format: Keiko Shinjo, Xingxing Wang, Kohei Kumegawa, Reo Maruyama, Shinji Mii, Yoshiteru Murofushi, Miho Suzuki, Atsushi Enomoto, Yutaka Kondo. Integrated multiomics analysis revealed the significance of Transgelin in driving pancreatic cancer-associated fibroblast-mediated cancer 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 1589.
Abstract 1637: EPHB4 is a key regulator of G1/S transition in hepatocellular carcinoma
Authors: Husain Abdullah , Chiu Elley Y. , Ma Hoi-Tang , Ho Daniel W. , Sze Karen M. , Chan Lo-Kong , Ng Irene O.
Published: March 2024

Effective therapeutic regimens against advanced hepatocellular carcinoma (HCCs) have recently improved but it remains very limited. Targeting receptor tyrosine kinases (RTKs) has proven to one of the main ways of achieving better survival outcome in HCC patients, yet the precise mechanism for this success remains to be elusive. We have systematically investigated the expression profiles of RTKs transcriptomic datasets i.e. The Cancer Genome Atlas - Liver hepatocellular carcinoma (TCGA-LIHC) (n=371) and our in-house cohort of paired i.e. HKU-QMH (n=41), and identified EPHB4 as one of the most abundantly expressed and frequently mutated RTKs in human HCCs. EPHB4 expression was found to be significantly correlated with Alpha Fetoprotein (AFP) expression, a factor commonly used in the diagnosis of HCCs. Furthermore, EphB4 has been demonstrated to play a regulatory role in VEGF/VEGFR-mediated angiogenesis, critical targets for current successful drugs. We confirmed abundant membrane EphB4 expression in HCC clinical specimens and human HCC cell line models using immunohistochemistry. Clinicopathological correlation analysis of EPHB4 mRNA expression revealed that its overexpression is associated with aggressive tumor features including presence of tumor microsatellite, liver invasion, venous invasion, and absence of tumor encapsulation. Functionally, stably knocking down EPHB4 (shEPHB4) resulted in a strong reduction of proliferation and self-renewal rates of multiple HCC cell lines in vitro. It significantly reduced tumor growth rates in subcutaneous and liver orthotopic models in vivo. Furthermore, limiting dilution assay showed EPHB4 plays a role in tumor initiation property of HCC cells. Mechanistically, we performed Gene Set Enrichment Analysis (GSEA) of transcriptome profiles for shEPHB4 with respective controls and found that knocking down EPHB4 causes HCC cells undergo drastic changes in several cell cycle checkpoints including G1/S transition. Using thymidine blockade, we further confirmed that knockdown of significantly hinders the transition of HCC cells from G1 to S phase of cell cycle. Our data suggests a strong link between EphB4 and cell cycle. Conclusion: We found EphB4 plays a functional role in regulating G1/S transition in human HCCs and understanding regulatory role of EphB4 on cell cycle progression may provide mechanistic insights into the how to effectively target HCC in the clinic.

Citation Format: Abdullah Husain, Elley Y. Chiu, Hoi-Tang Ma, Daniel W. Ho, Karen M. Sze, Lo-Kong Chan, Irene O. Ng. EPHB4 is a key regulator of G1/S transition in hepatocellular 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 1637.
Abstract 1656: ISM6331, a novel and potent pan-TEAD inhibitor, exhibits strong anti-tumor activity in preclinical models of Hippo pathway-dysregulated cancers
Authors: Li Qi , Wan Jainfei , Liu Jinxin , Shang Jing , Yu Jiaojiao , Zhu Wei , Chen Celia X.-J. , Qiao Junwen , Wang Ling , Zhang Man , Ding Xiao , Bavadekar Supriya , Rao Sujata , Ren Feng , Zhavoronkov Alex
Published: March 2024

The Hippo-YAP/TAZ-TEAD signaling pathway plays critical roles in tumorigenesis and tumor progression. Genetic alterations of Hippo pathway regulators, such as NF2 or LATS1/2, have been shown to induce YAP/TAZ-TEAD transcriptional activity, promoting initiation and progression of many solid tumors. In addition, many studies have shown that YAP/TAZ-TEAD activation mediates resistance to multiple targeted therapies, particularly EGFR-KRas-MAPK pathway inhibitors. The TEAD family of transcription factors (TEAD1/2/3/4) share structural similarity and have overlapping functions in tumor development and TEAD auto-palmitoylation is critical for its interaction with YAP/TAZ and its transcriptional function. Therefore, blocking TEAD palmitoylation and allosterically disrupting YAP/TAZ-TEAD-mediated transcriptional regulation, is emerging as a promising approach for the treatment of tumors with Hippo pathway dysregulation.

In this work, ISM6331, a novel and potent TEAD inhibitor with excellent inhibition against TEAD1/2/3/4 was identified leveraging an AI generative model. ISM6331 reversibly binds to the TEAD palmitoylation site and significantly suppresses TEAD transcriptional activity. ISM6331 potently and selectively inhibited the growth of many Hippo pathway-dysregulated tumor cells and dose-dependently suppressed the expression of TEAD target genes in vitro. In NF2-deficient or LATS1/2-mutant in vivo mesothelioma models, ISM6331 exhibited promising anti-tumor efficacy as monotherapy in a dose-dependent manner from 3 to 30mg/kg. ISM6331 also showed synergism with EGFR or KRasG12C inhibitors in inhibiting tumor cell growth and overcame drug resistance in in vitro and in vivo models. In addition, ISM6331 showed excellent pharmacokinetic properties in multiple preclinical species and was well-tolerated in GLP-toxicity studies. In summary, ISM6331 has promising potential to treat Hippo pathway-dysregulated tumors as monotherapy as well as in combination with targeted therapies.

Citation Format: Qi Li, Jainfei Wan, Jinxin Liu, Jing Shang, Jiaojiao Yu, Wei Zhu, Celia X.-J. Chen, Junwen Qiao, Ling Wang, Man Zhang, Xiao Ding, Supriya Bavadekar, Sujata Rao, Feng Ren, Alex Zhavoronkov. ISM6331, a novel and potent pan-TEAD inhibitor, exhibits strong anti-tumor activity in preclinical models of Hippo pathway-dysregulated 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 1656.
Abstract 1688: Nuclear receptor coactivator SRC-1 promotes colorectal cancer immune escape by enhancing PD-L1 transcription and protein stability
Authors: Hong Yilin , Chen Qiang , Wang Zinan , Zhang Yong , Li Bei , Kong Xu , Mo Pingli , Xiao Nengming , Xu Jianming , Ye Yunbin , Yu Chundong
Published: March 2024

Programmed death-ligand 1 (PD-L1), one of the immunosuppressive molecules, overexpresses in multiple cancers and is critical for their immune escape. We previously showed that the nuclear coactivator SRC-1 promoted colorectal cancer (CRC) progression by enhancing CRC cell viability; however, the role of SRC-1 in CRC immune escape is unclear. Here, we demonstrated that SRC-1 was positively correlated with PD-L1 in human CRC specimens. SRC-1 deficiency significantly inhibited PD-L1 expression in both human and murine CRC cells and retarded murine CRC growth in subcutaneous grafts by enhancing CRC immune escape via increasing tumor infiltration and antitumor activity of effector CD8+ T cells. Genetic ablation of SRC-1 in mice also decreased PD-L1 expression in AOM/DSS-induced murine CRC. These results suggest that tumor-derived SRC-1 promotes CRC immune escape by enhancing PD-L1 expression. Mechanistically, SRC-1 activated JAK-STAT signaling by inhibiting SOCS1 expression and coactivated STAT3 and IRF1 to enhance PD-L1 transcription as well as stabilized PD-L1 protein by inhibiting proteasome-dependent degradation mediated by speckle type POZ protein (SPOP). Pharmacological inhibition of SRC-1 improved the antitumor effect of PD-L1 antibody in both subcutaneous graft and AOM/DSS-induced murine CRC models. Taken together, our findings highlight a crucial role of SRC-1 in facilitating CRC immune escape and targeting SRC-1 in combination with PD-L1 antibody immunotherapy may be an attractive strategy for CRC treatment.

Citation Format: Yilin Hong, Qiang Chen, Zinan Wang, Yong Zhang, Bei Li, Xu Kong, Pingli Mo, Nengming Xiao, Jianming Xu, Yunbin Ye, Chundong Yu. Nuclear receptor coactivator SRC-1 promotes colorectal cancer immune escape by enhancing PD-L1 transcription and protein stability [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 1688.
Abstract 1700: Interplay of pioneer and chromatin remodeling factors: New insights into breast cancer mechanisms
Authors: Takaku Motoki , Cooper Mikhal , Saotome Mika
Published: March 2024

Eukaryotic cells utilize chromatin to package their genomic DNA, which can hinder transcription factor binding and gene activation. Pioneer factors, which can activate silent chromatin by binding to nucleosomes in closed (inactive) chromatin regions, thereby increasing chromatin accessibility, are essential in multiple developmental pathways. Their misregulation has been linked to various human diseases, including cancer. Yet, the involvement of pioneer factor mutations in tumorigenesis and tumor progression remains largely unexplored. GATA3 is one of the most frequently mutated genes in breast cancer. We and other groups found that a subset of GATA3 mutations promote tumor growth by redirecting luminal transcriptional network governed by Estrogen Receptor alpha (ER-alpha), FOXA1, and GATA3. Our genomics data also suggested that GATA3 requires multiple co-factors to maintain and establish active enhancers. Through IP-mass spectrometry, we identified several chromatin remodeling factors as potential GATA3 binding partners, with CHD4 being particularly notable. Our genomic data, including ChIP-seq, ATAC-seq, and RNA-seq, suggest that during GATA3-induced mesenchymal-to-epithelial transition (MET), CHD4 plays a critical role in maintaining closed chromatin structure, particularly at enhancer regions. Depletion of CHD4 results in the activation of chromatin and genes that are not essential for successful MET. Furthermore, we observed functional interactions between GATA3 and PARP1 in both luminal and basal breast cancer cells, with notable changes in GATA3 mutant cells. Through these studies, we aim to uncover epigenetic vulnerabilities in GATA3-altered breast cancer cells, ultimately contributing to the development of new breast cancer treatments.

Citation Format: Motoki Takaku, Mikhal Cooper, Mika Saotome. Interplay of pioneer and chromatin remodeling factors: New insights into breast cancer mechanisms [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 1700.
Abstract 1708: Transposable element derived enhancers in ovarian cancer
Authors: Nguyen Lily L. , Ivancevic Atma , Bitler Benjamin G. , Chuong Edward B.
Published: March 2024

There is global epigenetic dysregulation during transformation from normal to cancerous cells. One of the many consequences of this global epigenetic dysregulation is the reactivation of transposable elements (TEs). TEs compose roughly half of the human genome and are normally repressed through epigenetic mechanisms such as DNA methylation and histone modifications. Endogenous retroviruses (ERVs) are a class of TEs that contain long terminal repeats (LTRs) with putative gene regulatory motifs. LTRs can be co-opted to be pro-tumorigenic by becoming non-canonical promotors for oncogenic genes. While several examples of TE-derived promotors have been reported in cancer, the potential significance of TE-derived enhancers remains largely unexplored. Here, we utilized publicly available multi-omics datasets (bulk and single-cell ATAC-seq, bulk and single-cell RNA-seq, and chromatin profiling) in the context of ovarian cancer to determine if there are tumor specific, TE-derived-enhancers that have gene regulatory function. We used CRISPRi technology to functionally validate a putative TE-derived enhancer and gene regulatory axis. We discovered that on the bulk tissue level, several TE families are enriched at open chromatin sites and sites marked by H3K27Ac (enhancer mark) of ovarian tumors, suggesting the presence of tumor specific, TE-derived enhancers. On the single-cell level, we discovered that ovarian cells have the highest expression of these TE transcripts compared to stromal and immune cells in the tumor microenvironment, suggesting that the increased TE-derived enhancer activity observed on the bulk level are specific to ovarian cells. Lastly, when we silenced a specific LTR18 locus upstream of a gene, TIPARP, TIPARP gene expression was also repressed, suggesting that these putative TE-derived enhancers have gene regulatory function. Determining the regulatory role of these TE-derived enhancers will provide novel insights into cancer-related transcriptomes.

Citation Format: Lily L. Nguyen, Atma Ivancevic, Benjamin G. Bitler, Edward B. Chuong. Transposable element derived enhancers in ovarian 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 1708.
Abstract 1725: Role of PRMT5 in neuroendocrine prostate cancer development
Authors: Nam Hye Seung , Deng Xuehong , Hu Chang-Deng
Published: March 2024

Background: Neuroendocrine prostate cancer (NEPC) is a lethal subtype of prostate cancer responsible for an estimated 20-30% of castration resistant prostate cancer (CRPC) deaths. While NEPC can arise de novo, the majority of these cases emerge as treatment-induced NEPC (tNEPC). Our data establish PRMT5:MEP50 as a key epigenetic regulator in NEPC and provide a potential predictive biomarker for tNEPC.

Methods: Here we generated an in vitro cell culture model and mouse model to mimic the clinical conditions in androgen signaling inhibitor (ASI) or androgen deprivation treatment (ADT) We developed an in vitro cell culture and in vivo model to mimic the clinical conditions in enzalutamide-resistant prostate cancer. Regulation and role of protein arginine methyltransferase 5 (PRMT5) and its cofactor methylosome protein 50 (MEP50) were determined by treating cells and mice tumors with doxycycline inducible-shRNAs and catalytic inhibitors followed by analysis of cell viability, neurite growth, and effects on neuroendocrine related gene transcription. Pro-NEPC development effects were analyzed by immunofluorescence, immunohistochemical analysis, and western blot. PRMT5:MEP50-dependent methyltransferase activity was further validated by observing histone deposition levels via western blot and ChIP-qPCR. For clinical correlation, PRMT5 and MEP50 expression levels were comprehensively analyzed in both CRPC and NEPC patient prostate tissue samples.

Results: Our clinical and computational analyses have identified increased expression of PRMT5:MEP50 in NEPC. Overexpression of PRMT5 and MEP50 in prostate cancer cells is sufficient to induce neuroendocrine differentiation (NED) in prostate cancer cells. Gene depletion of PRMT5 and MEP50 prevented the NE phenotype induced by androgen receptor inhibition and resensitized the prostate cancer cells to ASI/ADT. PRMT5 and MEP50 facilitate chromatin modulation through the dimethylation of H4R3, which is highly correlated with the NED phenotype. Moreover, overexpression of PRMT5 and MEP50 in mouse prostate induces NEPC development, and gene downregulation can prevent NED in a xenograft mouse model. Elevated PRMT5 and MEP50 correlated with increased recurrence in prostate cancer patients receiving ADT and their recurrence probability after the treatment.

Conclusion: Our data establish PRMT5:MEP50 as a key epigenetic regulator in NEPC and provide a potential predictive biomarker for tNEPC.

Citation Format: Hye Seung Nam, Xuehong Deng, Chang-Deng Hu. Role of PRMT5 in neuroendocrine prostate cancer development [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 1725.
Abstract 1742: A universal spike-in normalization strategy for CUT&RUN, CUT&Tag and ATAC-seq
Authors: Traynor Sarah , Townsley Bradley , Weber Julianna , Jelinek Mary Anne , Egan Brian , Delatte Benjamin
Published: March 2024

The development of simple and efficient genome-wide approaches has recently democratized the study of epigenetics. For instance, CUT&RUN and CUT&Tag were developed as fast and affordable alternatives to ChIP-seq, whereas ATAC-seq readily identifies regions of open chromatin. These methods are ideal to look for genome-wide alterations in chromatin structures but are only semi-quantitative and can miss global changes when performed without normalization spike-ins. In fact, many standard computational pipelines fail to detect a reportedly substantial global H3K27me3 decrease in the presence of GSK126, a therapeutic target for lymphoma and potent inhibitor of the EZH2 methyltransferase. To overcome this challenge, we developed a spike-in approach using Drosophila melanogaster nuclei for normalization of ATAC, CUT&RUN and CUT&Tag experiments using human cells. The addition of the spiked-in nuclei allowed for the detection of the expected global changes in open regions of chromatin (ATAC-seq), H3K27me3 (CUT&Tag), R-loops (CUT&Tag), EED and p53 binding (CUT&RUN) upon treatment of K562 cells with GSK126. By contrast, these same changes were all missed when omitting the spike-in nuclei. This streamlined spike-in normalization strategy can be easily applied to any number of cells and on a large variety of conditions.

Citation Format: Sarah Traynor, Bradley Townsley, Julianna Weber, Mary Anne Jelinek, Brian Egan, Benjamin Delatte. A universal spike-in normalization strategy for CUT&RUN, CUT&Tag and ATAC-seq [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 1742.
Abstract 1749: Esophageal adenocarcinoma single-cell resolution ecotypes and subtypes mediate chemoradiation resistance
Authors: Ye Rui , Qiao Yawei , Bai Shanshan , Sei Emi , Hu Min , He Jianzhong , Li Nan , Wang Yifan , Lopez Pablo , Zhang Wei , Ye Fei , Weston Brian , Coronel Emmanuel , Ross William , Ge Phillip , Manoop Bhutani , Navin Nicholas , Lin Steven
Published: March 2024

Esophageal adenocarcinoma (EAC) is an aggressive and lethal disease with a 5-year survival rate less than 20%. The current standard of care for locally advanced EAC patients is neoadjuvant chemoradiation (CRT) followed by surgery and the pathological response rate is low in clinic. An unresolved question is how the cancer cells and their tumor microenvironment (TME) mediate CRT resistance in EAC. To address this question, we performed single-cell RNA sequencing on 84 longitudinal samples from a cohort of patients (N=47) containing 20 good responders (GR) and 27 non-responders (NR). In total, we obtained 302,918 single cells which enabled us to delineate the phenotypic heterogeneity landscape in EAC at baseline, and identify reprogramming in both the immune and tumor cells during treatment that lead to CRT resistance. We identified 4 major cell type compartments in the EAC TME: lymphoid cells (T cells, NK cells, B cells, and plasma cells), myeloid cells (macrophages, neutrophils, dendritic cells, and mast cells), stromal cells (fibroblasts and endothelial cells) and epithelial cells. Our data shows that the TME enriched in lymphoid cells, including resident and effector memory CD8 T cells, follicular helper CD4 T cells, and B cells was associated with better CRT responses. Moreover, a significant myeloid cell infiltration was observed across most patients during CRT and the infiltrated macrophages from GR harbored a more pro-inflammation phenotype. In addition, we identified 4 major ecotypes of the TME cells and 4 major expression subtypes of the cancer cells. Notably, the interactions between TME ecotypes and cancer subtypes are significantly associated with CRT responsiveness. In summary, this study has provided valuable insights into the biology of EAC CRT response, and identified novel predictive biomarkers and actionable targets to enhance CRT efficacy.

Citation Format: Rui Ye, Yawei Qiao, Shanshan Bai, Emi Sei, Min Hu, Jianzhong He, Nan Li, Yifan Wang, Pablo Lopez, Wei Zhang, Fei Ye, Brian Weston, Emmanuel Coronel, William Ross, Phillip Ge, Bhutani Manoop, Nicholas Navin, Steven Lin. Esophageal adenocarcinoma single-cell resolution ecotypes and subtypes mediate chemoradiation resistance [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 1749.
Abstract 1807: New strategies to target the pseudokinase receptor PTK7 in the Wnt pathway
Authors: Borg Jean-Paul , Pierre Manon , Ganier Laetitia , Daulat Avais , Molliex Amandine , Duez Julien , Sanchez Maxime , Lallemand Etienne , Goncalves Anthony , Bollot Guillaume
Published: March 2024

Colorectal cancer (CRC) remains the second cause of death by cancer worldwide and its survival is currently estimated at 60%1. There is therefore a crucial need to identify biomarkers and new targets for therapy. In 90% of CRC, the Wnt/β-catenin pathway is constitutively activated due to mutations of β-catenin, APC (Adenomatous Polyposis Coli) or axin-12. These alterations cause an accumulation of β-catenin and lead to an over-transcription of target genes involved in tumorigenesis3-4. Studies of our team pointed out an overexpression of the Protein Tyrosine Kinase 7 (PTK7) in CRC, an event associated with metastatic development, reduced metastases-free survival, and resistance to chemotherapy. In CRC cells, the pseudokinase PTK7 has pro-metastatic and pro-migratory functions, and thus appears to be a promising new therapeutic target5-6. The role of PTK7 in the Wnt/β-catenin pathway has been demonstrated in several studies7-8. Our group identified β-catenin as a partner of PTK7. We selected a first series of small molecules inhibitors targeting PTK7/β-catenin interaction9. This strategy could represent, in the future, a new therapeutic strategy to inhibit CRC cell growth dependent on the Wnt signaling pathway. However, the compounds identified had weak activity, with an IC50 of around 10-25 mM. We have set up a new method with SYNSIGHT to select more potent chemical inhibitors targeting PTK7/β-catenin in CRC in order to counteract the Wnt/β-catenin signaling pathway deregulation. References: 1Colorectal cancer (Source : Globocan 2020); 2Cancer Genome Atlas Network. Nature. 2012; 3He, T. C. et al. Science. 1998; 4Tetsu, O. & McCormick, F. Nature. 1999; 5Lhoumeau, A.-C. et al. PLOS ONE. 2015; 6Lhoumeau, A.-C. et al. J. Immunol. 2016; 7Puppo, F. et al. EMBO Rep. 2011; 8Peradziryi, H. et al. EMBO J. 2011; 9Ganier, L. et al. ACS Chem. Biol. 2022; 10Daulat, A. M. & Borg, J.-P. Trends Cancer. 2017; 11Stamos, J. L. & Weis, W. I. Cold Spring Harb. Perspect. Biol. 2013.

Citation Format: Jean-Paul Borg, Manon Pierre, Laetitia Ganier, Avais Daulat, Amandine Molliex, Julien Duez, Maxime Sanchez, Etienne Lallemand, Anthony Goncalves, Guillaume Bollot. New strategies to target the pseudokinase receptor PTK7 in the Wnt pathway [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 1807.
Abstract 1809: Discovery of novel AXL and MER inhibitors as potential anticancer and immunomodulatory drugs
Authors: Hsieh Hsing-Pang , Li Mu-Chun , Yen Wan-Ching , Wu Su-Ying , Yeh Teng-Kuang , Kuo Ching-Chuan , Ueng Shau-Hua , Wu Han-Chung
Published: March 2024

In cancer progression, abnormal AXL expression can promote tumor growth, metastasis, and chemotherapy resistance, while MER can identify apoptotic cancer cells and induce immune suppression in the tumor microenvironment. Combining AXL and MER inhibitors could generate a synergistic effect, enhancing antitumor responses, and further suppressing resistance formed by monotherapy with AXL selective or MER selective inhibitors. According to the explicit function of AXL and MER, the development of dual AXL and MER inhibitors may provide tremendous advantages to cancer patients. Drawing on our experience in the discovery of an anti-EGFR and anti-HER2 clinical candidate, we introduced several AXL-active and MER-active pharmacophores into DBPR112. Furthermore, we modified the scaffold and the solubilizing groups to improve the drug-like properties. Our comprehensive structure-activity relationship study led to the discovery of several potent dual AXL and MER inhibitors. Among approximately 200 synthesized compounds, BPR5K230 demonstrated strong inhibitory activities against AXL and MER, along with favorable oral bioavailability (F% = 55%) and promising in vivo antitumor effects in various mouse xenograft models, including MDA-MB-231, 4T1, and MC-38 tumor models. BPR5K230 effectively addressed sorafenib resistance in the Hepa 1-6 model and exhibited significant synergistic antitumor effects when combined with an anti-PD-L1 antibody in the EMT-6 model. As a result, BPR5K230 represents a promising dual AXL/MER kinase inhibitor, and further preclinical evaluation is underway for its development as a potential anticancer and immune-modulating drug.

Citation Format: Hsing-Pang Hsieh, Mu-Chun Li, Wan-Ching Yen, Su-Ying Wu, Teng-Kuang Yeh, Ching-Chuan Kuo, Shau-Hua Ueng, Han-Chung Wu. Discovery of novel AXL and MER inhibitors as potential anticancer and immunomodulatory drugs [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 1809.
Abstract 1824: Hexadecanoic acid mediated cell cycle arrest involving inhibition of cell migration
Authors: Wright Sasha-gay A. , Aiken William , Asemota Helen , Foster Kimberly , Delgoda Rupika
Published: March 2024

The Caribbean region accounts for the highest incidence and mortality rates of prostate cancer in the world. This warrants the need for targeted therapy as currently the most prevalent and effective option include chemotherapeutic drugs. Previous studies showed that an enriched sample extracted from the Jamaican Round Leaf yellow yam exhibited antiproliferative effects on DU145 prostate cancer cells. Based on the results obtained, this present study aims at exploring the underlying mechanism of action as well as the antimetastatic activities that the yam derived hexadecanoic acid may exhibit. Flow cytometry analysis was used to assess cell cycle arrest exhibited by hexadecanoic acid on the hormone insensitive DU145 prostate cancer cells. The western blot analysis was then utilized to determine the effects of the hexadecanoic acid enriched sample on cyclins in the cells. Transwell migration assays were then used to evaluate cell metastatic capabilities. Hexadecanoic acid enriched sample induced G1 S cell cycle arrest in the hormone insensitive prostate cancer cell line. Western blot assays also indicated that cell death was possibly induced through the cell cycle regulatory protein, cyclin D1 as its expression was downregulated in the treatment groups. Additionally, the observed metastatic inhibition of prostate cancer cells due to the action of the hexadecanoic acid in the wound healing assay may be attributed to a mechanism involving cyclin D1 as studies have indicated that abnormal Ccnd1 Cdk4 expression promotes tumor growth and metastasis. These results are substantial as it indicates a mechanistic pathway through which hexadecanoic acid is able to cause antiproliferative effects through a cell cycle arrest of hormone insensitive prostate cancer cell lines.

Citation Format: Sasha-gay A. Wright, William Aiken, Helen Asemota, Kimberly Foster, Rupika Delgoda. Hexadecanoic acid mediated cell cycle arrest involving inhibition of cell migration [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 1824.
Abstract 1829: Brusatol overcomes tyrosine kinase inhibitors resistance in myeloid leukemia cells by inhibiting translation of fast turnover protein cyclin D1 and Mcl-1
Authors: Hua Huiming , Yang Ying , Lin Guangfuxin , Zhang Jingyi , Waxman Samuel , Jing Yongkui
Published: March 2024

Myeloid leukemia is characterized with fast proliferation and apoptosis evasion, which are controlled by mutant or activated tyrosine kinase signalings. Tyrosine kinase inhibitors (TKI) targeting BCR-ABL in chronic myeloid leukemia (CML) and FLT3-ITD in acute myeloid leukemia (AML) significantly improved the therapy, but not cure, due to the general resistance. Overactivated mTOR protein translation pathway is believed to be one of the mechanisms causing resistance and that targeting protein translation should be one effective approach to overcome resistance. Brusatol is a quassinoid extracted from the fruit of Brucea javanica and an inhibitor of protein translation. We tested its antiproliferation and apoptosis induction in a variety of AML and CML cell lines as well as in TKI resistant cell lines. Brusatol effectively inhibits the growth of seven leukemia cell lines with GI50 values less than 20 nM. Brusatol induces apoptosis in AML cell lines and induces G0/G1 phase arrest in CML cell lines. Brusatol decreases the levels of fast turnover protein cyclin D1 and Mcl-1. In FLT3-ITD inhibitor sorafenib resistant MOLM-13/Sor cell line brusatol exhibits similar growth inhibition and apoptosis induction with the parental MOLM-13 cells, associated with inhibition of Mcl-1 and FLT3-ITD proteins. In BCR-ABL inhibitor imatinib resistant K562/STI cell line brusatol is effective as in parental K562 cells, associated with inhibition of cyclin D1 and BCR-ABL proteins. Brusatol at 2 mg/kg effectively inhibit tumor growth of K562 xenografts without causing toxicity to normal organs. These data indicate that brusatol inhibits oncogenic protein translation and has potential to be used to treat TKI resistant leukemia.

Citation Format: Huiming Hua, Ying Yang, Guangfuxin Lin, Jingyi Zhang, Samuel Waxman, Yongkui Jing. Brusatol overcomes tyrosine kinase inhibitors resistance in myeloid leukemia cells by inhibiting translation of fast turnover protein cyclin D1 and Mcl-1 [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 1829.