tbuckley/cabot-search huggingface dataset:
Abstract A112: Mechanisms underlying platinum-induced ovarian cancer stem cell plasticity
Authors: Tara X. Metcalfe, Shu Zhang, Christiane Hassel, Heather M. O'Hagan, Kenneth P. Nephew
Journal: Cancer Research (2024)

Abstract Most women diagnosed with late-stage high grade serous ovarian cancer (HGSOC) develop recurrent, platinum-resistant tumors. Ovarian cancer stem cells (OCSCs) are hypothesized to contribute to the emergence of these resistant tumors. CSCs have been postulated to reside in a plastic state, which can allow for the conversion of non-CSC to CSC. This process of dedifferentiation continues during tumor development and chemotherapeutic agents like platinum can exaggerate CSC plasticity. We have previously demonstrated that acute platinum treatment enriched for OCSCs. However, whether platinum transforms non-OCSCs into OCSCs to contribute to this subpopulation of cells remains unclear, and the underlying mechanism remains incompletely understood. To examine OCSC plasticity, aldehyde dehydrogenase (ALDH; functional marker) and fluorescence activated cell sorting were used to isolate OCSCs (ALDH+) and non-OCSCs (ALDH-) from HGSOC cell lines, OVCAR5 and OVCAR3. To determine the stability of the non-OCSC phenotype, ALDH- cells were cultured for 3 and 5 days and ALDH activity was measured using flow cytometry. At both timepoints examined, ALDH- cells remained ALDH-, with approximately less than 1% being ALDH+ (p&amp;lt;0.05). To determine if platinum can induce conversion of non-OCSC to OCSC, ALDH- cells were treated with cisplatin (12µM or 15 µM for 16h), and the percent of ALDH+ cells was measured using flow cytometry. Treatment of ALDH- cells with cisplatin resulted in conversion of approximately 4% and 10% of ALDH- cells into ALDH+ cells (p&amp;lt;0.05) in OVCAR5 and OVCAR3 cells, respectively. Furthermore, both cell lines displayed increased expression (p&amp;lt;0.05) of stemness genes BMI1, NANOG, OCT4, and SOX2 and spheroid formation was observed in converted OCSCs compared to parental ALDH+ and whole cell populations treated with cisplatin, suggesting that platinum induced the observed differences in the stemness phenotype. With the goal of targeting key genes and pathways to inhibit platinum-induced OCSC conversion, RNA-sequencing was performed using converted OCSCs. Activated pathways in converted OCSCs were identified, including protein kinase signaling, inhibition of matrix metalloproteases, SPINK1 pathway, and VDR/RXR activation. We are further investigating if these pathways contribute to the mechanism involved in OCSC plasticity and whether targeting these pathways can reduce the OCSC population, which is critical to blocking the persistence of OCSCs and ultimately reduce mortality in patients. Citation Format: Tara X. Metcalfe, Shu Zhang, Christiane Hassel, Heather M. O'Hagan, Kenneth P. Nephew. Mechanisms underlying platinum-induced ovarian cancer stem cell plasticity [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr A112.
Abstract A093: Investigating alterations in metabolic profile of ovarian carcinoma associated mesenchymal stem cells
Authors: Roja Baruwal, Leonard G. Frisbie, Lan Coffman
Journal: Cancer Research (2024)

Abstract Ovarian cancer causes more deaths than any other gynecologic cancer. Although aerobic glycolysis has been a hallmark of cancer metabolism, it has been found that ovarian cancer (OvCa) cells are metabolically plastic, also utilizing oxidative phosphorylation (OXPHOS) as an active metabolic pathway for their rapid proliferation and metastasis. A growing body of evidence also shows that cancer cells not only reprogram their own metabolism but also metabolically remodel the tumor microenvironment to meet their ever-increasing energy demand. Our lab has previously demonstrated that OvCa cells epigenetically reprogram their resident tissue mesenchymal stromal/stem cells (MSCs) to develop a cancer-supportive phenotype. These cancer-associated mesenchymal stem cells (CA-MSCs) support OvCa progression through several mechanisms, including enhanced metastasis. Recent work by our lab showed these CA-MSCs enhance metastasis by donating their mitochondria to metabolically vulnerable OvCa cells and increasing OvCa cell OXPHOS. While we have demonstrated the impact of CA-MSC mitochondrial transfer to OvCa cells, what changes are happening in the CA-MSC that allow them to transfer mitochondria to OvCa cells is still unknown. Gene set enrichment analysis performed on RNA sequencing data comparing patient derived CA-MSCs to normal MSCs revealed that OXPHOS is one of the top enriched pathways in CA-MSCs. Furthermore, the cell mito stress test comparing mitochondrial respiratory profile of patient derived normal MSCs and CA-MSCs demonstrated that CA-MSCs have significantly increased mitochondrial respiratory capacity compared to normal MSCs. Uncovering the metabolic profile of ovarian CA-MSCs for the first time, our data demonstrates that ovarian cancer alter the metabolism of the CA-MSC towards OXPHOS. Our current studies are focused on understanding the role of enhanced CA-MSC OXPHOS in mitochondrial transfer to OvCa cells and OvCa metastasis. Citation Format: Roja Baruwal, Leonard G. Frisbie, Lan Coffman. Investigating alterations in metabolic profile of ovarian carcinoma associated mesenchymal stem cells [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr A093.
Abstract A098: Microenvironment-regulated matrix Gla protein drives ovarian cancer stemness
Authors: Valentina Nieddu, Valentina Melocchi, Chiara Battistini, Giulia Franciosa, Michela Lupia, Jesper Olsen, Nicoletta Colombo, Fabrizio Bianchi, Ugo Cavallaro
Journal: Cancer Research (2024)

Abstract The clinical evolution of ovarian cancer (OC), with peritoneal dissemination, tumor relapse and chemoresistance, seems to be accounted for by a small population of ovarian cancer stem cells (OCSC), thus making them an attractive target for more efficacious treatments. However, this could only be achieved through the detailed characterization of the molecular and functional traits of this elusive cell subpopulation. Therefore, the identification of novel OCSC-associated targets and therapeutic approaches may offer alternative treatment options. We established a new platform of patient-derived organotypic models of OC and found that Matrix Gla Protein (MGP) was upregulated in cancer cells upon contact with the peritoneal tumor microenvironment. MGP is classically known as a vitamin K-dependent calcium chelator, mainly associated with the inhibition of tissue calcification and cardiovascular disease. In addition, MGP is also aberrantly expressed in different cancer types, but the biological mechanisms that regulate its functional contribution to cancer progression is still unknown. Our transcriptomic profiling of primary OCSC versus their non-stem counterpart pointed to MGP as a potential driver of cancer stemness. Indeed, we obtained evidence that MGP promotes, and is required for, stemness-associated biological features in vitro and in animal models, including sphere formation and tumor initiation. MGP was also implicated in the regulation of the expression of several key genes involved in stemness and/or EMT. Finally, MGP was upregulated in OC patients following chemotherapy, suggesting that the protein may be involved in OCSC-driven chemoresistance. The molecular mechanisms underlying MGP-regulated OCSC pathophysiology were investigated by RNA sequencing experiments on MGP-manipulated OC cells, which unveiled genetic networks and pathways that are orchestrated by MGP to promote OCSC function. The biological role of MGP in OC provides novel insight into the biology of OCSC, thus defining new pathways involved in OC stemness and paving the way to innovative therapeutic strategies for OC eradication. Citation Format: Valentina Nieddu, Valentina Melocchi, Chiara Battistini, Giulia Franciosa, Michela Lupia, Jesper Olsen, Nicoletta Colombo, Fabrizio Bianchi, Ugo Cavallaro. Microenvironment-regulated matrix Gla protein drives ovarian cancer stemness [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr A098.
Abstract A084: AMH paracrine signaling between cancer and mesothelial cells modulates the ovarian tumor immune microenvironment
Authors: Maeva Y. Chauvin
Journal: Cancer Research (2024)

Abstract Introduction: Cancer-associated mesothelial cells (CAMCs) have emerged as significant contributors to the tumor microenvironment, influencing tumor growth and immune evasion. Mesothelial cells represent the first point of contact of ovarian cancer cells during their peritoneal spread. Normal omental mesothelial cells have been reported to play a role in immune surveillance of the peritoneal cavity. However, beyond their initial involvement during the seeding of cancer cells to the omentum, the role of omental mesothelial cells in the subsequent development of the tumor microenvironment and the immune evasion of the tumor remains poorly understood. Methods: To study the role of mesothelial cells in the tumor microenvironment, we recently generated novel syngeneic mouse models of high grade serous ovarian cancer, which were derived from Fallopian tube epithelium, and bear human-relevant mutational genotypes. We analysed one such model, the CCNE1-amplified KPCA cell line, using single cell transcriptomics in omental metastases to survey the pattern of expression of the anti-Müllerian hormone (Amh) and its receptor Amhr2 across tumor cell types. Results: Single-cell transcriptomics revealed specific expression of Amhr2 in cancer-associated mesothelial cells, but not normal omental mesothelium. The co-culture of cancer cells with normal omental mesothelial cells induced AMHR2 expression along with a pro-tumorigenic cancer-associated mesothelial cell transcriptomic signature. Overexpression of AMHR2 in a human immortalized mesothelial cell line (Met5a) significantly modulated the expression of genes involved in immune response pathways, remodeling of extra-cellular matrix, and secretion of growth factors. Furthermore, we showed that AMH was secreted by ovarian cancer cells and downregulated key immunomodulatory cytokines (Ccl2, Cxcl2/3, Il1a/b) secreted by CAMCs, thus promoting immunosuppression within the tumor. Finally, implantation of ovarian cancer cells into syngeneic Amhr2−/− hosts produced tumors that grew significantly slower than in wild type hosts, which contained significantly reduced populations of exhausted T cells as marked by PD1 and CTLA4 expression. Conclusion: Together these data suggest that AMHR2 expression is necessary for the reprogramming of mesothelial cells into CAMCs and represents a specific marker of CAMCs in ovarian cancer. The AMH-AMHR2 paracrine axis between cancer cells and CAMCs modulates the tumor microenvironment to promote growth and immune evasion and may represent a novel target for immunotherapy in ovarian cancer. Citation Format: Maeva Y. Chauvin. AMH paracrine signaling between cancer and mesothelial cells modulates the ovarian tumor immune microenvironment [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr A084.
Abstract A100: Entinostat alters the M1/M2 ratio in ascites compared to tumors derived from an ID8 murine model of ovarian cancer
Authors: Vijayalaxmi Gupta, Katherine Roby, SImona Miceska, Andrew Wilson, Fiona Yull, Marta Crispens, Wendy Zhang, Dineo Khabele
Journal: Cancer Research (2024)

Abstract Poly ADP ribose inhibitors (PARPi) are most effective in ovarian cancer tumors with homologous recombination (HR) deficiency. Our group has shown that histone deacetylase inhibitors (HDACi) sensitize HR proficient ovarian cancer cells to PARPi. Our current efforts are directed towards understanding how this therapeutic regimen alters tumor-associated macrophages (TAMs) in murine models of high grade serous ovarian cancer. To investigate the effects of Ola combined with Ent, we used HR-proficient ID8 P53 wild-type and ID8 P53−/− syngeneic murine models. Mice were randomized into 4 groups: control, Ola, Ent and Ola+Ent. Mice (Ent and Ola+Ent) were pre-treated with 15 mg/kg entinostat or vehicle (Ola and Ola+Ent) for one week via oral gavage and then treated with vehicle/Ent/Ola (100 mg/kg)/Ola+Ent for two weeks. Mice were sacrificed 24 h after the last dose to harvest tumors and ascites. Tumors were processed for histology to determine cell proliferation (Ki67) and immune cell markers (CCL2, M1 and M2-like macrophages). Ascites fluid was processed for flow cytometric analysis of immune cells. Tumors from parental ID8 P53 wild type mice showed significantly lower cell proliferation marker Ki67 (P&amp;lt;0.05), higher anti-tumorigenic M1-like CCL2 (P&amp;lt;0.05), and lower pro-tumorigenic M2-like mannose receptor (P&amp;lt;0.05) in Ent and Ola+Ent groups compared to vehicle and Ola. Ascites showed no significant change in anti-tumorigenic M1-like macrophages, but significantly increased pro-tumorigenic M2-like macrophages (P&amp;lt;0.005). Arginase-1, another marker of M1 macrophage, assessed by IF also confirmed significant decrease in pro-tumorigenic M2-like macrophage in Ent and Ola+Ent treated mice tumors. Additional immune cell markers identified in ascites are being analyzed. To summarize, in ID8 syngeneic mouse models, Ola and Ent treatment exerted anti-tumorigenic effects in tumors but potentially pro-tumorigenic effects in ascites. In conclusion, concomitant targeting of tumor TAMs and ascites TAMs may be a therapeutic regimen to investigate in the future. Citation Format: Vijayalaxmi Gupta, Katherine Roby, SImona Miceska, Andrew Wilson, Fiona Yull, Marta Crispens, Wendy Zhang, Dineo Khabele. Entinostat alters the M1/M2 ratio in ascites compared to tumors derived from an ID8 murine model of ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr A100.
Abstract A101: A novel ovarian cancer organotypic tumor slice culture model
Authors: Violaine Pourcel, Emile Létourneau, Dominique Jean, Marilyne Labrie
Journal: Cancer Research (2024)

Abstract High-grade serous ovarian carcinoma (HGSOC) is the most common form of ovarian cancer (OC). This heterogeneous disease is associated with various molecular alterations influencing the disease course. Unfortunately, the impact of those molecular alterations on the response to therapy is still misunderstood. Few OC models allow control of genetic background in the cancer cells while preserving the tumor's architecture and microenvironment, including the immune cells. Furthermore, there is currently no high-throughput model that retains those characteristics and is suitable for drug screens. This project aims to develop a high-throughput syngeneic murine organotypic tumor slice culture model to study the impact of common HGSOC molecular alterations on anticancer drug responses. The pre-established Trp53−/− syngeneic OC mouse model has been genetically engineered to represent molecular alterations frequently found in HGSC. Ten variants were produced by overexpressing Tp53R172h and overexpressing oncogenes such as Ccne, Brd4, Myc, Ndrg1, and Pik3ca and/or deleting Brca1, Pten, and Nf1. After validation and characterization of the cells in vitro, we performed allografts in immunocompetent C57/bl6 mice and obtained tumors with HGSOC histology. The tumors were used to develop an organotypic tumor slice culture model. Briefly, each tumor is collected and thinly sliced with a vibratome. Each slice can be cultured for several days without significant cell death induction and can be used for a drug screen. Our preliminary data shows that the model preserves the HGSOC histology over six days and remains viable. A viability assay has also been developed to assess the sensitivity of the tumor slices to various anticancer drugs. In conclusion, this project will allow the development of a platform for screening anticancer therapies against HGSOC and will lead to a better understanding of the relationship between HGSOC's common molecular alterations and the responses to therapy. Citation Format: Violaine Pourcel, Emile Létourneau, Dominique Jean, Marilyne Labrie. A novel ovarian cancer organotypic tumor slice culture model [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr A101.
Abstract B017: Understanding the impact of transporter heterogeneity on the efficacy of PARP inhibitors
Authors: Carmen Ramirez Moncayo, Guanying Zhang, Alexis Barr, Vincen Wu, Christina Fotopoulou, Paula Cunnea, Zoe Hall, Louise Fets
Journal: Cancer Research (2024)

Abstract While PARP inhibitors have undoubtedly enhanced the prognosis of high-grade serous ovarian cancer (HGSOC) patients, variability in response and acquired drug resistance remain persistent hurdles undermining these drugs' effectiveness. One of the multiple mechanisms of resistance ascribed to PARP inhibitors involves transporter-dependent detoxification, facilitated by the overexpression of the multidrug-resistant protein MDR1, which couples ATP hydrolysis to drug efflux. Conversely, the Solute Carrier (SLC) family of transporters plays a role in the cellular uptake of multiple therapeutic compounds, whereby the presence and abundance of the relevant transporter at the plasma membrane may dictate intracellular concentration of the drug, with subsequent clinical implications. Despite these findings, our understanding of PARP inhibitor drug uptake mechanisms, and how heterogeneity of transporter expression limits drug efficacy, remains limited. To better understand this, we employed a combination of cell-based high-content microscopy assays and multimodal molecular tissue imaging techniques to investigate the heterogeneity in response to PARP inhibitors and their relationship to drug distribution. Mass spectrometry imaging of human HGSOC tumor explants demonstrated intra-tumor heterogeneity in PARP inhibitor uptake within clinical samples. Even at the single cell level, heterogeneity in PARP inhibitor uptake was observed, and this was seen to correlate with levels of DNA damage, suggesting that differences in drug distribution may limit PARP inhibitor response and contribute to acquired drug resistance. Taken together, this data suggests that diverse transporter signatures in cancer could contribute to patient-to-patient variability in PARP inhibitor response. The identification of the molecular determinants of the heterogeneity hitherto described might contribute towards a better understanding of drug sensitivity and acquired drug resistance, with the idea of improving patient stratification in the context of personalized medicine. Citation Format: Carmen Ramirez Moncayo, Guanying Zhang, Alexis Barr, Vincen Wu, Christina Fotopoulou, Paula Cunnea, Zoe Hall, Louise Fets. Understanding the impact of transporter heterogeneity on the efficacy of PARP inhibitors [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr B017.
Abstract B034: Targeting the HER family/Src pathways in ovarian cancer
Authors: Neil T. Conlon, Elena Mörhle, Denis M. Collins, John Crown
Journal: Cancer Research (2024)

Abstract Background: Targeting EGFR and HER2 has been highly successful across several cancer types, but has been underexplored in ovarian cancer (OC), with several studies suggesting EGFR and HER2 is commonly over-expressed in epithelial OC. The irreversible pan-HER inhibitor neratinib has demonstrated clinical activity in HER2-mutant and HER2-overexpressing cancers and we have previously shown that neratinib plus the multi-kinase inhibitor dasatinib is highly synergistic in ovarian and breast cancers. Targeting the Src family kinases has involved the use of broad multi-kinase inhibitors such as dasatinib and bosutinib. However, NXP-900 is a novel orally bioavailable small molecule selective inhibitor of Src family kinases that may have synergistic efficacy with reduced off-target effects. The aim of this study was to investigate the potential of NXP-900 in combination with the pan-HER inhibitor neratinib in OC. Methods: The anti-proliferative effects of Src inhibitors, dasatinib (multi-kinase) or NXP-900 (Src selective), plus neratinib were tested in SKOV3, OVCAR3, PEO1 and IGROV-1 cell lines. Synergism was assessed using Combenefit software with the Loewe additivity model. Induction of caspase 3/7 activation, a marker of apoptosis, and the effects on cell migration with single agent and combination treatment were assessed using the Incucyte S3 imaging system. Downstream signaling alteration were investigated by Western blotting. Results: The combination of neratinib with either dasatinib or NXP-900 was highly synergistic across the cell lines. NXP-900 had little anti-proliferative activity as a single agent but significantly enhanced the effect of neratinib at nanomolar concentrations. Dasatinib showed potent single agent activity and synergies with neratinib across cell lines. SKOV3 cell line displayed the greatest synergy with both combinations and was selected for further characterization. Src inhibition alone inhibited cell migration, and further migration suppression was observed with the addition of neratinib. The combination stimulated apoptosis induction and resulted in on-target signaling inhibition in SKOV3 cells. Conclusions: This pre-clinical study showed that inhibition of the HER family and Src family kinases may have a strong anti-proliferative effect in OC models. Citation Format: Neil T. Conlon, Elena Mörhle, Denis M. Collins, John Crown. Targeting the HER family/Src pathways in ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr B034.
Unpacking Firearm Access and Firearm Violence Exposure Among American Indian or Alaskan Native and Black Adults
Authors: Amelia C. Mueller-Williams, Lara N. Coughlin, Jason E. Goldstick
Journal: JAMA Network Open (2024)

Michael D. Anestis, PhD; Jayna Moceri-Brooks, PhD, RN; Devon Ziminski, MS; R. Thurman Barnes, JD, MDiv; Daniel Semenza, PhD