bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1095: Exploiting altered methionine metabolism to overcome treatment resistance in glioblastoma
Authors: Korimerla Navyateja , Romans Kari-Wilder , Kalev Peter , Kothari Ayesha , Qi Nathan , Evans Charles , Kachman Maureen , Hyer Marc L , Marjon Katya , Sleger Taryn , Wahl Daniel R
Published: April 2023

Glioblastoma (GBM) is the most aggressive adult brain tumor and is uniformly fatal due to resistance to standard therapies such as radiation (RT) and chemotherapy. Our group and others have identified altered metabolism as a key mediator of GBM RT resistance. Methionine is an essential sulfur-containing amino acid that cells use to synthesize antioxidants, polyamines and S-adenosyl methionine (SAM), which drives intracellular methylation reactions. Methionine uptake is dramatically elevated in GBM compared to normal brain, but what GBMs use this methionine for, and whether it governs GBM treatment resistance, is unknown. Here, we find that RT acutely increases the levels of numerous methionine-related metabolites in multiple RT-resistant GBM models. To interrogate metabolic pathway activity, we used 13C5 methionine stable isotope tracing to show that GBMs respond to RT by activating the conversion of methionine to SAM, which is dependent on signaling through the DNA damage response. We developed in vivo methionine stable isotope tracing techniques to confirm these findings in orthotopic PDX models of GBM. Blocking the conversion of methionine to SAM, through pharmacologic inhibition of methionine adenosyltransferase 2A (MAT2A), slowed the repair of RT-induced DNA damage and increased cell death in GBM models following RT. These effects were especially pronounced in GBM models lacking the methionine salvage enzyme methylthioadenosine phosphorylase (MTAP). Pharmacologic inhibition of MAT2A in flank and orthotopic in vivo GBM models depleted SAM levels and slowed tumor growth when combined with RT. Combining MAT2A inhibition with dietary methionine restriction and RT slowed GBM tumor growth even further. Together, our work demonstrates a new signaling link between DNA damage and methionine-driven SAM synthesis in GBM. Inhibiting SAM synthesis slows the repair of RT-induced DNA damage and augments RT efficacy. This therapeutic strategy may be especially effective in GBMs defective in methionine salvage and spare normal cortex in which methionine salvage is active.

Citation Format: Navyateja Korimerla, Kari-Wilder Romans, Peter Kalev, Ayesha Kothari, Nathan Qi, Charles Evans, Maureen Kachman, Marc L Hyer, Katya Marjon, Taryn Sleger, Daniel R Wahl. Exploiting altered methionine metabolism to overcome treatment resistance in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1095.
Abstract 1232: Gastroesophageal reflux disease promotes E-cadherin cleavage and activates EMT via APE1-redox function in esophageal adenocarcinoma
Authors: Lu Heng , Cao Longlong , Ballout Farah , Belkhiri Abbes , Peng Dunfa , Chen Lei , Soutto Mohammed , McDonald Oliver , Zaika Alexander , Que Jianwen , El-Rifai Wael
Published: April 2023

The incidence of esophageal adenocarcinoma (EAC) has increased rapidly over the past four decades. Chronic gastroesophageal reflux disease (GERD), where acidic bile salts (ABS) abnormally refluxate into the esophagus, is the leading risk factor for the development of a metaplastic condition known as Barrett’s esophagus (BE) and its progression to EAC. We used 3D organotypic culture, mouse and human tissue samples to assess the role of ABS in Epithelial-to-Mesenchymal Transition (EMT) in EAC. Analysis of public databases revealed significant enrichment of EMT signaling in EAC progression. RNA-seq analysis of EAC cells showed activation of EMT pathway in response to ABS exposure. ABS induced multiple characteristics of the EMT process, such as downregulation of E-cadherin, upregulation of Vimentin, activation of ß-catenin and EMT-transcription factors (EMT-TFs), cell morphological changes, and enhancement of cell migration and invasion capabilities. Mechanistically, we discovered that ABS induced E-cadherin cleavage via MMP14 proteolytic cascade. APE1 silencing, or APE1-redox-specific inhibitor (E3330), abrogated the ABS-induced EMT process and signaling by downregulating MMP14. Furthermore, APE1 and MMP14 co-expression levels were inversely correlated with E-cadherin expression in gastroesophageal junctions of human EAC tissues, and the L2-IL1ß transgenic mouse model of BE/EAC. EAC patients with high APE1 and EMT signatures had worse relapse free survival than those with low signature. In a summary, this study demonstrates the role of ABS in promoting EMT via the redox-sensitive signaling axis of APE1/MMP14/E-cadherin/ß-catenin. Pharmacological inhibition of APE1-redox function could be a potential therapeutic approach to effectively reduce the risk of Barrett’s carcinogenesis.

Citation Format: Heng Lu, Longlong Cao, Farah Ballout, Abbes Belkhiri, Dunfa Peng, Lei Chen, Mohammed Soutto, Oliver McDonald, Alexander Zaika, Jianwen Que, Wael El-Rifai. Gastroesophageal reflux disease promotes E-cadherin cleavage and activates EMT via APE1-redox function in esophageal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1232.
Abstract 1234: Tumor cell-intrinsic PD-L1 promotes epithelial-to-mesenchymal transition in non-small cell lung cancer in interferon-g-independent and dependent way
Authors: Jeong Hyein , Ahn Hyun Kyung , Kim Sehui , Jeon Yoon Kyung
Published: April 2023

The immune checkpoint molecule programmed cell death-ligand 1 (PD-L1, CD274) suppresses immunity when the cell surface PD-L1 is engaged by programmed death-1 (PD-1) on antitumor immune cells. Although PD-L1 has been established and targeted in cancer immunotherapy, the tumor-intrinsic role of PD-L1 is less appreciated in tumor biology and therapeutic development. In this study, we showed that PD-L1 facilitates epithelial-to-mesenchymal transition (EMT) in non-small cell lung cancer (NSCLC) cells by upregulating EMT transcription factors and mesenchymal markers, and downregulating epithelial marker. RNA-sequencing was performed on paired exogenously PD-L1-overexpressed A549 cells and wild-type cells, and PD-L1-depleted H460 cells and wild-type cells, and transcriptomic features associated with PD-L1 status were identified using Gene Set Enrichment Analysis (GSEA). In both the paired samples, PD-L1 expression was associated with EMT-related pathways. Subsequent in vitro experiment showed that exogenous overexpression of PD-L1 in A549 and H522 cells increased both mRNA and protein expression of Twist, Zeb1, Snail, Slug, Vimentin, Fibronectin, and N-Cadherin. Correspondingly, the transcription factors and mesenchymal markers were decreased in PD-L1-depleted H460 and H596 cells. Recombinant PD-1 treatment also increased the expression of EMT transcription factors and markers on A549 and H460 cells. Moreover, interferon-γ stimulation on tumor cells increased expression of EMT transcription factors and markers, which was suppressed by PD-L1-knockdown, suggesting that interferon-γ-induced PD-L1 contributes to EMT. Our findings suggest that PD-L1 facilitates NSCLC progression by promoting the EMT in interferon-γ-independent and dependent way, and this intrinsic PD-L1 function could be targeted for better clinical management of PD-L1-overexpressing NSCLCs.

Citation Format: Hyein Jeong, Hyun Kyung Ahn, Sehui Kim, Yoon Kyung Jeon. Tumor cell-intrinsic PD-L1 promotes epithelial-to-mesenchymal transition in non-small cell lung cancer in interferon-g-independent and dependent way [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1234.
Abstract 1246: Single-cell profiles of multiplexed in vivo models facilitate the characterization of phenotypic plasticity and invasion in glioblastoma
Authors: Hara Toshiro , Chanoch-Myers Rony , Greenwald Alissa , Bussema Lillian , Behnan Jinan , Galli Rossella , Wakimoto Hiroaki , Tirosh Itay , Suvà Mario
Published: April 2023

The lethality of glioblastoma and the failure of surgical treatment are in part attributable to the invasive properties of this cancer; however, our understanding of the cell-biological process is limited due to the complex representation of invasion phenotype in glioblastoma models. Here, to overcome this limitation, we developed an in vivo approach with human glioblastoma spheroid lines multiplexed for mouse intracranial xenografts. We validated this with 20 patient-derived models and identified, by 3’end single-cell RNA-sequencing (scRNA-seq) coupled with deconvolution analysis, in vivo models capable of infiltrating along the periphery of either neurons or blood vessels. We previously found that the diverse malignant cells in glioblastoma specimens exist in a limited set of four cellular states: neural progenitor-like (NPC-like), oligodendrocyte progenitor-like (OPC-like), astrocyte-like (AC-like), and mesenchymal-like (MES-like), with potential for state plasticity under the influence of tumor microenvironment. To determine whether or not the cell state heterogeneity is implicated in glioblastoma invasion, we profiled and characterized programs, states, and clonality of invading glioblastoma cells by comparing cells from the contralateral invasive edge to their counterparts residing at the original bulk tumor. This analysis showed evidence of a bi-directional state transitioning model for cells undergoing distinct environmental spaces. Exploration of cell state distribution at the primary tumors revealed that presence of an OPC-like state was significantly associated with invasion phenotype regardless of the infiltration routes. Our results suggest that cellular plasticity may be a prerequisite for the topographically diffusive nature of glioblastoma, urging further assessment by perturbing critical regulators of the cellular state programs. In conclusion, this work describes multiplexed in vivo models as an enabling platform for the rapid interrogation of patient-derived xenografts, coupling the molecularly measurable states with functional identity driving malignant phenotypes such as cancer invasion.

Citation Format: Toshiro Hara, Rony Chanoch-Myers, Alissa Greenwald, Lillian Bussema, Jinan Behnan, Rossella Galli, Hiroaki Wakimoto, Itay Tirosh, Mario Suvà. Single-cell profiles of multiplexed in vivo models facilitate the characterization of phenotypic plasticity and invasion in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1246.
Abstract 1256: Transglutaminase-2 is elevated in the invasive cell state and modulates the tumor immune microenvironment in cutaneous melanoma
Authors: Caksa Signe , Wilski Nicole A. , Kitterman Erica L. , Glasheen McKenna Q. , Heilizer Jacob S. , Purwin Timothy J. , Capparelli Claudia , Aplin Andrew E.
Published: April 2023

Cutaneous melanoma is the most fatal skin cancer; resistance to targeted therapies contributes to poor prognosis. In some cases, resistance arises from pre-existing tumor heterogeneity, which allows subpopulations of drug-tolerant cells with distinct transcriptional states to survive in the presence of drug. The loss of SOX10, a lineage-specific transcription factor, is known to drive melanoma phenotype switching from a proliferative to an invasive drug-tolerant state. Here, we found that knocking out SOX10 in human and mouse melanoma cell lines leads to the upregulation of transglutaminase-2 (TGM2), a calcium-dependent cross-linking enzyme. Analysis of publicly available bulk and single-cell RNA-sequencing data showed that TGM2 is highly expressed in the invasive cell state in melanoma cell lines and patient-derived melanoma cultures, respectively. Furthermore, knockdown of SOX10 in patient-derived melanoma cultures increases TGM2 mRNA expression. 3D spheroid assays and extracellular matrix production/remodeling assays showed that knockdown of TGM2 has no effect on the invasiveness of SOX10-deficient cells. However, we found that TGM2 is secreted by SOX10-deficient cells and hypothesized that it could modulate the tumor immune microenvironment (TIME) given that TGM2 has been associated with increased immune infiltration in melanoma patient samples. To investigate the effect of TGM2 on the TIME, we stably overexpressed TGM2/Tgm2 in syngeneic mouse melanoma cell lines and allowed tumors to grow in immune-competent C57BL/6 mice. As compared to empty vector, TGM2/Tgm2-overexpression led to an increase in the percentage and number of CD4+ T cells and B cells, and a decrease in the number of myeloid cells, in the tumor immune compartment by flow cytometry analysis. Future studies will assess which subsets of CD4+ T cells and B cells infiltrate TGM2/Tgm2-overexpressing tumors, how these changes to the TIME affect melanoma invasiveness, and if TGM2 expression affects response to targeted therapy in vivo. Overall, our data suggest that TGM2 is highly expressed in the invasive melanoma cell state, is regulated by the SOX10 transcription factor, and can modulate adaptive immune cells in the TIME.

Citation Format: Signe Caksa, Nicole A. Wilski, Erica L. Kitterman, McKenna Q. Glasheen, Jacob S. Heilizer, Timothy J. Purwin, Claudia Capparelli, Andrew E. Aplin. Transglutaminase-2 is elevated in the invasive cell state and modulates the tumor immune microenvironment in cutaneous melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1256.
Abstract 1280: Role of soluble mesothelin in peritoneal metastasis
Authors: Panchwagh Neel M. , Ewa Theressa , Avula Leela Rani , Joseph Sarah , Tai Chin-Hsien , Sevilla Samantha , Koparde Vishal , Zhang Xianyu , Alewine Christine
Published: April 2023

The cell-surface glycoprotein mesothelin (MSLN) is overexpressed in pancreatic adenocarcinoma (PDAC) and is positively correlated with tumor aggressiveness. MSLN knock-out (KO) PDAC cells have delayed growth of peritoneal metastases in mice. Complementation with wild-type MSLN rescued the phenotype, although complementation with MSLN containing a Y318A point mutation to ablate interaction with MSLN binding partner MUC-16 could not. Mature MSLN is shed into the tumor microenvironment to generate soluble MSLN (sMSLN). We hypothesized that sMSLN would promote peritoneal metastasis. We engineered MSLN C-terminal truncation mutants (∆599-WT and ∆599-Y318A) that lack the membrane attachment site and exist only in soluble form. Parent and MSLN KO PDAC cells were transduced with the vector constructs. These cells were injected into athymic nude mice and peritoneal tumor growth was measured 6 weeks later. MSLN KO cells complemented with ∆599-WT MSLN exhibited poor peritoneal tumor growth, while ∆599-Y318A resulted in growth rescue. We considered that sMSLN might exert a dominant negative effect because it competes for MUC-16 binding with membrane-bound MSLN but cannot facilitate cell-to-cell interaction. Expression of ∆599-WT inhibited tumor growth in parent cells, while ∆599-Y318A failed to do so. The activity of ∆599-Y318A in KO cells remained unexplained. We hypothesized that levels of mircoRNA-198, a purported tumor suppressor regulated by MSLN, might be altered by ∆599 expression and correlate with phenotype rescue. However, no change in microRNA-198 expression was observed in ∆599-expressing cells. We are continuing to investigate the mechanism for a novel activity of sMSLN that is unrelated to MUC-16 binding.

Citation Format: Neel M. Panchwagh, Theressa Ewa, Leela Rani Avula, Sarah Joseph, Chin-Hsien Tai, Samantha Sevilla, Vishal Koparde, Xianyu Zhang, Christine Alewine. Role of soluble mesothelin in peritoneal metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1280.
Abstract 1281: Oncoprotein YB-1 modulation of Lyn-MAPK-NF-kB pathway, a potential therapeutic strategy combined with sorafenib for advanced stage HCC
Authors: Pazzi Ana G. Ayala , Karkoutly Omar , Ezell Kristopher , Lopez Samantha , Doxtater Kyle D. , George Elias , Dhevan Vijian , Tripathi Manish K.
Published: April 2023

The Y-Box Binding protein 1 (YB-1) is a 324 amino acid-long member of the Cold Shock Domain (CSD) protein superfamily. YB-1 interacts with micro RNAs and non-coding RNAs in the cytoplasm, acting as a regulator of mRNA translation. YB-1 translocation into the nucleus is circadian clock-dependent and leads to the upregulation of cyclin gene expression, among others. Another mechanism of nuclear translocation of YB-1 is mediated by phosphorylation of the Ser 102 residue in the CSD. The YB-1 oncoprotein acts as a transcription factor when bound to DNA, modulating the transcription of genes that regulate biological processes such as Multidrug Resistance Mutation 1 (MDR1). YB-1 is linked to poor prognosis in breast, prostate, and liver cancer. Despite advances in biomedicine, the incidence and mortality of hepatocellular carcinoma (HCC) remain high. Sorafenib, a tyrosine kinase Inhibitor (TKI), is the first-line treatment for advanced HCC. Sorafenib also inhibits downstream activation of NF-kB by inhibition of Lyn phosphorylation (Y397). However, it was observed in many patients that its sorafenib’s effectiveness is hampered by drug resistance, but the mechanism is still unclear. We have found that SK-HEP-1 HCC cells transfected with a YB-X-1 overexpression plasmid subsequently developed into a stable YB-1 overexpression cell line (SK-HEP-1+YB-1) displayed increased invasion, migration, proliferation, and colony formation property as compared to the vector control (SKHEP1+Vec). The SK-HEP-1+YB-1 cell line also showed increased IC50 for sorafenib and elevated phosphorylation of Lyn (Y397) and further activated NF-kB (S165/S176) phosphorylation. This indicates YB-1 may cause increased Sorafenib resistance in HCC by activating tyrosine kinases (TK), such as lyn, and simultaneous activation of NF-kB. The combination of YB-1 inhibition and sorafenib might provide a novel therapeutic strategy and improve the survival of patients with advanced-stage HCC.

Citation Format: Ana G. Ayala Pazzi, Omar Karkoutly, Kristopher Ezell, Samantha Lopez, Kyle D. Doxtater, Elias George, Vijian Dhevan, Manish K. Tripathi. Oncoprotein YB-1 modulation of Lyn-MAPK-NF-kB pathway, a potential therapeutic strategy combined with sorafenib for advanced stage HCC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1281.
Abstract 1292: CX3CR1 surface expression and phenotypic plasticity in metastasis-initiating cells
Authors: Zhang Jieyi , Oyende Yetunde , Lynch Jennifer , Meucci Olimpia , Fatatis Alessandro
Published: April 2023

Metastasis-initiating cells (MICs) display stem cell-like features and cause metastatic recurrences leading to patients' demise. We found that prostate and breast cancer cells with high surface expression of the chemokine receptor CX3CR1 (CX3CR1high) account for ~5-7% of the whole population and are endowed with metastasis-initiating ability and exhibits stemness features, including expression of pluripotency genes Nanog and Oct4a. Notably, impairing CX3CR1 signaling hinders metastatic initiation and progression in mouse models of human disease. We also found that cancer cells lacking surface CX3CR1 expression (CX3CR1low) can re-acquire CX3CR1-associated features over time by undergoing phenotypic plasticity. Accordingly, when grafted as pure CX3CR1low populations these cells could generate disseminated tumors in mice, implying that MICs can emerge from cancer cells lacking stemness features. In vitro studies by flow cytometry show that cell surface re-exposure of CX3CR1 by CX3CR1low cells begins within 2 days post-sorting, with the whole population reaching phenotypic equilibrium at 12-16 days post-sorting. Further mechanistic studies revealed that both CX3CR1 protein trafficking and transcriptional regulation play a role in phenotypic plasticity. Additionally, disseminated tumors in mice harbor higher percentages of CX3CR1high cells than in vitro cultures, suggesting that the tissue microenvironment of target organs promotes phenotypic plasticity. These findings nominate CX3CR1 as a novel marker of MICs and provide conceptual ground for future development of approaches targeting CX3CR1 signaling and (re)expression as therapeutic means to prevent or contain metastasis initiation and progression.

Citation Format: Jieyi Zhang, Yetunde Oyende, Jennifer Lynch, Olimpia Meucci, Alessandro Fatatis. CX3CR1 surface expression and phenotypic plasticity in metastasis-initiating cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1292.
Abstract 1362: Impact of chemotherapy on functional and biochemical characteristics of cancer-associated fibroblasts​
Authors: Xia Zihan , De Wever Olivier
Published: April 2023

Cancer-associated fibroblasts (CAFs), as the major components of the tumor microenvironment (TME), have been extensively explored and are known to be involved in tumor biology, including growth, energy metabolism, immune regulation, invasion and metastasis. A large number of preclinical studies describe the functional and biochemical impact of commonly used chemotherapeutics, such as paclitaxel and oxaliplatinum, on cancer cells, but their effect on the phenotypical and biochemical changes of CAFs and their reciprocal impact on tumor progression are lacking.

In our study, we used patient-derived breast and colorectal CAF to evaluate dose-response effects of paclitaxel and oxaliplatinum, respectively first-line chemotherapeutics in breast and colorectal cancer. We evaluated the damage responses of CAF and investigated changes in morphology, cell death, woundhealing migration, type I collagen contraction and invasion, cytokine and chemokine release, differential protein expression, and metabolic activity. In response to paracrine signals emerging from chemotherapy-treated CAF we investigated the impact on functional activity of macrophages, neutrophils and cancer cells. Our project could help us better understand and modulate the activity of CAFs, which might provide novel targets for the clinical treatment of cancer.

Citation Format: Zihan Xia, Olivier De Wever. Impact of chemotherapy on functional and biochemical characteristics of cancer-associated fibroblasts​ [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1362.
Abstract 1422: Fibroblast growth factor receptor-1 is a novel therapeutic target in mantle cell Lymphoma
Authors: Sircar Anuvrat , Singh Satishkumar , Young Ken H. , Epperla Narendranath , Sehgal Lalit
Published: April 2023

Cell cycle dysregulation and significant enrichment of E2F1 target genes are hallmarks of MCL, and the inability to directly target E2F1-dependent processes is a clinical hindrance. Despite several treatment options, mantle cell lymphoma is associated with poor clinical outcomes and the development of resistance. We identified Fibroblast Growth Factor Receptor-1 is upregulated in relapsed mantle cell lymphoma patients and high FGFR-1 expression in MCL correlates with poor overall and progression-free survival. Genetic ablation of FGFR1 in MCL cells induced cell cycle arrest, and cell death in-vitro, inhibited tumor progression, and improved overall survival in-vivo. Functionally, FGFR1 loss upregulates the expression of the cell-cycle dependent Kinase inhibitor 1C (CDKN1C) through epigenetic repression via EZH2. CDKN1C binds to E2F1 and regulates the transactivation of its target genes, including CDK1. CDK1 further stabilizes MYC and positively regulates the expression of EZH2, activating the feed-forward loop to promote cell survival. Conversely, losing FGFR1 disrupts this feed-forward loop in malignant cells. This is the first report establishing FGFR1 as a novel therapeutic target and providing a rationale to target FGFR1 to treat Mantle cell lymphoma and disrupt the feed-forward loops contributing to the survival of malignant cells.

Citation Format: Anuvrat Sircar, Satishkumar Singh, Ken H. Young, Narendranath Epperla, Lalit Sehgal. Fibroblast growth factor receptor-1 is a novel therapeutic target in mantle cell Lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1422.
Abstract 1446: The elevated expression of INSM1 is correlated with EZH2 in neuroendocrine prostate cancer
Authors: Li Lin , Cheng Siyuan , Yu Xiuping
Published: April 2023

Background: Neuroendocrine prostate cancer (NEPCa) is the most aggressive and non-targetable prostate cancer (PCa). It is well accepted that NEPCa arises from prostate adenocarcinoma (AdPCa) via trans-differentiation. NEPCa tumors exhibit a similar mutation burden but a different transcriptome profile from AdPCa. This suggests that the acquisition of the NE phenotype is driven by epigenetic, transcriptional reprogramming but not genetic alterations. Enhancer of zeste homolog 2 (EZH2), a histone methyltransferase, is an epigenetic regulator and upregulated in NEPCa. The upregulation of EZH2 in PCa has been considered to be correlated with therapy-induced plasticity and NE differentiation. Insulinoma-associated 1 (INSM1), is a zinc-finger transcription factor, which is predominantly expressed in neuroendocrine (NE) cells and important for the NE developmental pathways. INSM1 has been considered as a biomarker for multiple types of NE tumors, like pancreatic, lung, and prostate. Also, the increase level of INSM1 is associated with NE differentiation in PCa. Analysis of PCa transcriptomic profiles suggests that EZH2 and INSM1 have positive correlation in PCa and function together in NEPCa.

Methods: To study the expression of INSM1 and EZH2, we did immunofluorescence (IF), immunohistochemistry (IHC), Western blot and RT-qPCR in prostate cancer cell lines, mouse tissues, and human patients samples. The bioinformatics analysis was done using the publicly available RNA-Seq data obtained from the cBioportal, the Cancer Genome Atlas (TCGA), and the Cancer Cell Line Encyclopedia websites (CCLE).

Results and Conclusion: Our IHC results confirmed that INSM1 is highly expressed in NEPCa rather that AdPCa in both human and mouse tissues. By IF, we further found that INSM1 also expresses in PCa amphicrine cells. Additionally, we found that the expression of INSM1 is positively associated with EZH2 expression in PCa. These data indicates that INSM1 may act as a marker for not only NE cells but also amphicrine cells in PCa. Also the correlation between INSM1 and EZH2 further indicates the importance of INSM1 in NEPCa. Our further study will focus on how INSM1 functions and whether there’s a direct regulation between INSM1 and EZH2.

Acknowledgement: This work was supported by NIH R01 CA226285, and the Feist-Weiller Cancer Center (FWCC).

Citation Format: Lin Li, Siyuan Cheng, Xiuping Yu. The elevated expression of INSM1 is correlated with EZH2 in neuroendocrine prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1446.
Abstract 1450: Global changes in RBPs and mRNA interactions during prostate cancer progression
Authors: Dwead Abdulrahman M. , Al-Mathkour Marwah M. , Cinar Bekir
Published: April 2023

Prostate cancer (PC) is a leading cause of cancer in men in the United States and worldwide, disproportionately affecting men of African ancestry. The etiology and molecular mechanism contributing to lethal human PC remain poorly understood. RNA binding proteins (RBPs) controlled all aspects of RNA biogenesis, and dysregulated RBPs are linked to human diseases, including cancer. However, the global changes in RBP-mRNA interactions during PC progression are unknown. Here, we have investigated the patterns of RBPs and polyA-mRNA interaction in the castration-sensitive LNCaP and castration-resistant C4-2 PC cell lines. Our enhanced-RNA interactome capture assay combined with mass spectroscopy (MS) revealed that LNCaP and C4-2 cells showed distinct RBP-mRNA interaction patterns in steady-state and androgen-treated conditions. Also, we have studied the interaction between Yes-associated protein 1 (YAP1) and nucleophosmin (NPM1) RBP. Androgen increased NPM1 and mRNA interaction, and NPM1 is part of the YAP1 multiprotein complex, as revealed by MS-based proteomics approaches. Our proximity ligation assay showed that androgen hormone signaling regulated the interaction between YAP1 and NPM1. Besides, our GST-pulldown demonstrated that NPM1 binds the proline-rich region domain of YAP1, whereas the WW/SH3 domain of YAP1 mediates the interaction in C4-2 cells. Genetic silencing of NPM1 reduced PC cell growth in culture. Furthermore, the upregulation of NPM1 correlates with prostate adenocarcinoma and metastasis. These observations suggest that changes in RBP and RNA interaction patterns may play a critical role in PC progression and recurrence.

Citation Format: Abdulrahman M. Dwead, Marwah M. Al-Mathkour, Bekir Cinar. Global changes in RBPs and mRNA interactions during prostate cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1450.
Abstract 1489: Overexpression of ribosomal L22-like1 (RPL22L1) enhances cancer stem cell properties and promotes tumor progression in hepatocellular carcinoma (HCC)
Authors: Huang JinLin , Guo Zhenyang , Luo Jie , Liu Beilei , Gong Lanqi , Fang Xiaona , Kwong Dora Lai-wan , Guan Xinyuan
Published: April 2023

The abnormality of ribosomal biogenesis is found to be involved in carcinogenesis and progression in various types of cancer. RPL22L1 gene is a highly homologous paralog of RPL22, both of which belong to the L22E family of ribosomal proteins and take part in encoding a cytoplasmic ribosomal protein that is a component of the 60S subunit of ribosomes. Our previous work has established a CRISPR/Cas9 genome-wide knockout screening profile and developed a two-component mixture model to identify cancer-specific essential genes in 436 cancer cell lines. Bioinformatics analysis reveals that RPL22L1 acts as a feature gene to predict cancer-specific essential genes in human cancer. Previous studies suggest that RPL22L1 is correlated with tumor progression and adverse prognosis in several cancer types, while its role in hepatocellular carcinoma (HCC) is unknown. In the present study, we found that RPL22L1 is highly expressed in embryonic stem cells (ES) and liver progenitor cells, which were acquired from a vitro hepatic differentiation model originating from ES cells. Hence, we hypothesized that RPL22L1 enhances cancer stem cell properties in HCC. Functional assays showed that RPL22L1 would promote sphere formation in vitro. qRT-PCR and Western Blotting results indicated that RPL22L1 could promote stemness-related gene expressions such as CD133, CD44, and SOX9 in HCC cell lines. Overexpression of RPL22L1 increased aldehyde dehydrogenase (ALDH) activity, which was decreased when RPL22L1 was silenced with short hairpin RNA (shRNA). Extreme limiting dilution assay showed that RPL22L1 overexpression stimulated self-renewal ability in immunodeficient mice. Furthermore, higher RPL22L1 expression can also promote cell proliferation and epithelial-mesenchymal-transition, as well as drug resistance to 5-Fluorouracil (5-FU) and cisplatin (CDDP). Silver nitrate staining demonstrated that RPL22L1 overexpression correlated with a larger size and number of nucleoli. The expression of RPL22L1 was also associated with adverse prognosis in HCC clinical samples. In conclusion, our study reveals aberrant ribosomal protein activity in HCC and the role of RPL22L1 in promoting HCC tumor progression.

Citation Format: JinLin Huang, Zhenyang Guo, Jie Luo, Beilei Liu, Lanqi Gong, Xiaona Fang, Dora Lai-wan Kwong, Xinyuan Guan. Overexpression of ribosomal L22-like1 (RPL22L1) enhances cancer stem cell properties and promotes tumor progression in hepatocellular carcinoma (HCC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1489.
Abstract 1491: Delineating the oncogenic mechanisms of NAT10 in hepatocellular carcinoma
Authors: Patrasso Emmely A. , Raikundalia Sweta P. , Arango Daniel
Published: April 2023

Protein synthesis is often dysregulated in cancer, highlighting the regulatory mechanisms of translation as potential targets for cancer treatment. With more than 140 chemical modifications of RNA, the epitranscriptome is a central mechanism in regulating protein synthesis. Remarkably, the epitranscriptome is often altered in cancerous tumors and under stress conditions such as reactive oxygen species (ROS) and anti-tumor therapies. For instance, N-acetyltransferase 10 (NAT10), the enzyme responsible for acetylating cytidines (N4-acetylcytidine or ac4C) in RNA, is highly overexpressed in cancers such as Hepatocellular Carcinoma (HCC). Of significant relevance to cancer, NAT10 is considered an oncogenic driver in fatty acid-induced HCC. Hence, this project aims to characterize the underlying oncogenic mechanisms of the NAT10/ac4C axis. Our data indicate that NAT10 and RNA acetylation levels are altered in response to fatty acids, ROS, and chemotherapeutic drugs. Likewise, we observed altered subcellular localization of NAT10 and ac4C in response to ROS and chemotherapeutic drugs. Building on our previous findings that NAT10-catalyzed ac4C promotes translation efficiency, our model stipulates that subcellular redistribution of the RNA acetyltransferase complexes enhances cell cycle progression, cancer cell proliferation, and cellular resilience by fine-tuning the translation of cancer driver genes. Collectively, our findings advance our understanding of how NAT10 promotes cancer growth while providing the mechanistic basis to target NAT10 for therapeutic purposes.

Citation Format: Emmely A. Patrasso, Sweta P. Raikundalia, Daniel Arango. Delineating the oncogenic mechanisms of NAT10 in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1491.
Abstract 1566: DNA damage generated by transcription-replication conflicts explains the synthetic lethality of PARP inhibitors with homologous recombination deficiency
Authors: Halazonetis Thanos D. , Petropoulos Michalis , Rossetti Giacomo G. , Karamichali Angeliki , Freudenmann Alena , Iacovino Luca , Dionellis Vasilis , Sotiriou Sotirios K.
Published: April 2023

An important advance in cancer therapy in the last decade has been the development of poly ADP-ribose polymerase (PARP) inhibitors for the treatment of select ovarian and breast cancers. The clinical benefit stems from the synthetic lethality of PARP inhibitors with homologous recombination (HR) deficiency, which deficiency is prevalent in the cancer types listed above. The current model to explain the synthetic lethality is based on the observation that PARP inhibitors trap PARPs on DNA: the trapped PARPs block progression of the replisome, leading to the formation of DNA double-strand breaks (DSBs), which require HR for repair.

Here, we propose a novel mechanism to explain the synthetic lethality between PARP inhibitors and HR deficiencies. We show that PARP1 functions together with the proteins TIMELESS and TIPIN to protect the replisome from transcription-replication conflicts (TRCs). In the absence of any one of these proteins, TRCs evolved into DNA DSBs that required HR for repair, explaining the observed synthetic lethality. In further support of this model, when we inhibited transcription elongation, which prevents the emergence of transcription-replication conflicts, then the HR-deficient cancer cells became resistant to PARP inhibitors.

We further observed that trapping of PARPs on DNA was not required for the synthetic lethality with HR deficiency, since we could observe strong synthetic lethality simply by depleting PARP1 and PARP2 by siRNA. Rather, trapping of PARPs on DNA correlated with the ability of the various PARP inhibitors to inhibit PARP enzymatic activity in cells; the strongest trappers were also the most potent inhibitors of PARP1 in cells. In vitro, all PARP inhibitors tested were almost equipotent in their ability to inhibit the enzymatic activity of PARP1, meaning that the potency of PARP1 inhibitors in vitro did not reflect their inhibitory potency in cells.

Our model provides a new framework for understanding the mechanism of action of PARP inhibitors in the clinic and the mechanisms by which resistance can emerge.

Citation Format: Thanos D. Halazonetis, Michalis Petropoulos, Giacomo G. Rossetti, Angeliki Karamichali, Alena Freudenmann, Luca Iacovino, Vasilis Dionellis, Sotirios K. Sotiriou. DNA damage generated by transcription-replication conflicts explains the synthetic lethality of PARP inhibitors with homologous recombination deficiency [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1566.
Abstract 1593: Synergistic effect of SH003 and Docetaxel by targeting a metabolic pathway in non-small cell lung cancer cells
Authors: Choi Yu-Jeong , Lee Kangwook , Kang Sooyeon , Lee Seo Yeon , Hwang Hyun-Ha , Ko Seong-Gyu
Published: April 2023

The identification of molecular biomarkers that can predict the response of cancer treatment facilitates more clear targeted therapy by lowering the side effect. Therefore, the present study investigated the key regulatory genes that determine the efficacy of SH003, a herbal medicine, combined with docetaxel (DTX) in non-small cell lung cancer cells. We identified that the combination treatment inhibited the process of the de novo biosynthesis of pyrimidine nucleotide via the reduction of the related enzyme expressions, resulting in DNA damage and apoptosis. However, we found that NSCLC cells have different sensitivities to combination treatment. As a result, the difference in sensitivity was determined by the p53 gene expression pattern of lung cancer cells, indicating that the treatment response of combination enhances by activating p53 in p53 wild-type lung cancer. Lung cancer cells harboring p53 mutations were resistant to the metabolic inhibition by the combination, whereas this effect was restored when p53 is expressed normally. In conclusion, this study revealed the genetic characteristics of cancer cells that are susceptible to treatment response when SH003 and DTX are combined, suggesting that p53 will be an important predictor of combination treatment.

Citation Format: Yu-Jeong Choi, Kangwook Lee, Sooyeon Kang, Seo Yeon Lee, Hyun-Ha Hwang, Seong-Gyu Ko. Synergistic effect of SH003 and Docetaxel by targeting a metabolic pathway in non-small cell lung cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1593.
Abstract 1600: Phase I trial of intravenous mistletoe extract in advanced cancer
Authors: Paller Channing J. , Wang Lin , Fu Wei , Kumar Rajedra , Durham Jennifer , Azad Nilofer , Laheru Daniel , Browner Ilene , Kachhap Sushant , Boyapati Kavya , Odeny Thomas , Armstrong Deborah , Meyer Christian , Gaillard Stephanie , Brahmer Julie , Page Ivelisse , Wang Hao , Diaz Luis A.
Published: April 2023

Purpose: Mistletoe extract is widely used in cancer patients to support therapy and to improve quality of life (QoL). However, its use is controversial due to suboptimal trials and a lack of data supporting its intravenous administration.

Patients and Methods: This phase I trial of intravenous Mistletoe (Helixor M) aimed to determine the recommended phase 2 dosing and to evaluate safety. Solid tumor patients progressing on at least one line of chemotherapy received escalating doses of Helixor M three times a week. Assessments were also made of tumor marker kinetics and QoL.

Results: Twenty-one patients were recruited. The median follow-up duration was 15.3 weeks. The maximum tolerated dose was 600mg. Treatment-related adverse events (AEs) occurred in 13 patients (61.9%), with the most common being fatigue (28.6%), nausea (9.5%), and chills (9.5%). Grade 3+ treatment-related AEs were noted in three patients (14.8%). Stable disease was observed in five patients who had 1-6 prior therapies. Reductions in baseline target lesions were observed in three patients who had 2-6 prior therapies. Objective responses were not observed. The disease control rate (percentage of complete/partial response and stable disease) was 23.8%. The median stable disease was 15 weeks. Serum cancer antigen-125 or carcinoembryonic antigen showed a slower rate of increase at higher dose levels. The median QoL by FACT-G increased from 79.7 at week 1 to 93 at week 4.

Conclusions: Intravenous mistletoe demonstrated manageable toxicities with disease control and improved QoL in a heavily pretreated solid tumor population. Future phase II trials are warranted.

Citation Format: Channing J. Paller, Lin Wang, Wei Fu, Rajedra Kumar, Jennifer Durham, Nilofer Azad, Daniel Laheru, Ilene Browner, Sushant Kachhap, Kavya Boyapati, Thomas Odeny, Deborah Armstrong, Christian Meyer, Stephanie Gaillard, Julie Brahmer, Ivelisse Page, Hao Wang, Luis A. Diaz. Phase I trial of intravenous mistletoe extract in advanced cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1600.
Abstract 1619: Generation of a novel estrogen receptor degrader
Authors: Liu Yuan , Kennerdell Jason R. , Lin Bo , Larsen Mads B. , Alfaras Irene , Camarco Daniel P. , Tuncer Ferhan , Finkel Toren , Chen Bill B.
Published: April 2023

Fulvestrant is an effective therapy to treat post-menopausal women with estrogen receptor (ER)-positive metastatic breast cancer. The compound works as a selective estrogen receptor degrader (SERD). Structurally similar to estrogen, fulvestrant binds to the ligand binding domain (LBD) of the ER, altering the stability of the protein, leading to its accelerated proteasomal degradation. While effective, fulvestrant must be given intramuscularly, which has limited its clinical adoption. Based on the success of fulvestrant, multiple attempts have been made to generate orally available SERDs. These attempts have focused on compounds that, like fulvestrant, bind within the LBD of the ER. Overall, these intensive efforts have generated limited success. We reasoned that it may be possible to identify potential SERDs that bind to the ER in regions outside the LBD. Such an approach would be useful for tumors bearing wildtype ER, and likely for those bearing a mutant form of the ER, since most mutations cluster in the LBD. We have recently developed a high throughput platform that allows for the identification of ligands that can bind to wide variety of protein targets. Using this approach, we screened a diverse chemical library of 100,000 small molecules to identify compounds that bind outside of the LBD, and in particular to the N-terminal region of the ER. This strategy identified CL-ER-100, a small molecule that directly bound to the N-terminal region of the ER and functioned as a SERD. While CL-ER-100 rapidly induced ER proteasomal-dependent degradation, it had no effect on the protein levels of other, structurally related nuclear receptors. Based on its structure and size (~ MW 300 Da), CL-ER-100 is expected to have excellent bioavailability. Consistent with its binding outside of the LBD, addition of tamoxifen had no effect on the ability of CL-ER-100 to induce ER protein degradation. In cells, CL-ER-100 was able to markedly inhibit the growth of breast cancer cell lines such as MCF7 and T47D (IC50 of ~ 100 nM) while not inhibiting the growth of a wide array of normal and non-breast cancer tumor cell lines. Taken together, these results identify a novel strategy to develop small molecule SERDs that induce ER protein degradation by binding to previously untargeted regions of the estrogen receptor.

Citation Format: Yuan Liu, Jason R. Kennerdell, Bo Lin, Mads B. Larsen, Irene Alfaras, Daniel P. Camarco, Ferhan Tuncer, Toren Finkel, Bill B. Chen. Generation of a novel estrogen receptor degrader [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1619.