Ovarian Progression Research Articles

Cancer-associated fibroblast-secreted FGF7 as an ovarian cancer progression promoter.

Ovarian cancer (OC) is distinguished by its aggressive nature and the limited efficacy of current treatment strategies. Recent studies have emphasized the significant role of cancer-associated fibroblasts (CAFs) in OC development and progression. Employing sophisticated machine learning techniques on bulk transcriptomic datasets, we identified fibroblast growth factor 7 (FGF7), derived from CAFs, as a potential oncogenic factor. We investigated the relationship between FGF7 expression and various clinical parameters. A series of in vitro experiments were undertaken to evaluate the effect of CAFs-derived FGF7 on OC cell activities, such as proliferation, migration, and invasion. Single-cell transcriptomic analysis was also conducted to elucidate the interaction between FGF7 and its receptor. Detailed mechanistic investigations sought to clarify the pathways through which FGF7 fosters OC progression. Our findings indicate that higher FGF7 levels correlate with advanced tumor stages, increased vascular invasion, and poorer prognosis. CAFs-derived FGF7 significantly enhanced OC cell proliferation, migration, and invasion. Single-cell analysis and in vitro studies revealed that CAFs-derived FGF7 inhibits the ubiquitination and degradation of hypoxia-inducible factor 1 alpha (HIF-1α) via FGFR2 interaction. Activation of the FGF7/HIF-1α pathway resulted in the upregulation of mesenchymal markers and downregulation of epithelial markers. Importantly, in vivo treatment with neutralizing antibodies targeting CAFs-derived FGF7 substantially reduced tumor growth. Neutralizing FGF7 in the medium or inhibiting HIF-1α signaling reversed the effects of FGF7-mediated EMT, emphasizing the dependence of FGF7-mediated EMT on HIF-1α activation. These findings suggest that targeting the FGF7/HIF-1α/EMT axis may offer new therapeutic opportunities to intervene in OC progression.

Honokiol induces ferroptosis in ovarian cancer cells through the regulation of YAP by OTUB2.

Ovarian cancer (OVCA) is prevalent in female reproductive organs. Despite recent advances, clinical outcomes remain poor, warranting fresh treatment avenues. Honokiol has an inhibitory effect on proliferation, invasion, and survival of cancer cells in vitro and in vivo. Therefore, this study intended to explore specific molecular mechanism by which honokiol affected OVCA progression. Bioinformatics analyzed the drug honokiol that bound to OTU deubiquitinase, ubiquitin aldehyde binding 2 (OTUB2). Cellular thermal shift assay (CETSA) verified the binding relationship between honokiol and OTUB2. Cell counting kit 8 (CCK-8) tested the IC50 value and cell viability of OVCA cells after honokiol treatment. Corresponding assay kits determined malonic dialdehyde (MDA) and Fe2+ levels in OVCA cells. Flow cytometry measured reactive oxygen species levels. Western blot detected OTUB2, SLC7A11, and transcriptional co-activators Yes-associated protein (YAP) expression, and quantitative polymerase chain reaction (qPCR) detected OTUB2 expression. Immunohistochemistry (IHC) detected the expression level of Ki67 protein in tumor tissues. Honokiol was capable of inducing ferroptosis in OVCA cells. CETSA confirmed that honokiol could bind to OTUB2. Further cell functional and molecular experiments revealed that honokiol induced ferroptosis in OVCA cells via repression of YAP signaling pathway through binding to OTUB2. In addition, in vivo experiments have confirmed that honokiol could inhibit the growth of OVCA. Honokiol induced ferroptosis in OVCA cells via repression of YAP signaling pathway through binding to OTUB2, implicating that OTUB2 may be an effective target for OVCA treatment, and our study results may provide new directions for development of more effective OVCA treatment strategies.

XTP8 Promotes Ovarian Cancer Progression by Activating AKT/AMPK/mTOR Pathway to Regulate EMT

Ovarian cancer (OC) ranks as the fifth leading cause of cancer-related death in women. The main contributors to the poor prognosis of ovarian cancer are the high rates of recurrence and metastasis. Studies have indicated a crucial role for hepatitis B virus X Ag-Transactivated Protein 8 (XTP8), a protein containing the DEP domain, in various cellular processes, including cell growth, movement, and differentiation, across several types of cancers. However, the role of XTP8 in ovarian cancer remains unclear. We observed elevated expression of XTP8 in ovarian cancer. Silencing XTP8 inhibited cell proliferation, promoted apoptosis, and yielded contrasting results in cells overexpressing XTP8. Furthermore, XTP8 facilitated ovarian cancer invasion and migration, triggering epithelial-mesenchymal transition (EMT). Mechanistically, XTP8 silencing led to reduced phosphorylation levels of AKT, increased p-AMPK levels, and decreased p-mTOR levels, while XTP8 overexpression exerted the opposite effects. Additionally, the activation of p-AMPK rescued the promoting effect of XTP8 on EMT in ovarian cancer cell lines, indicating that XTP8 acts as an oncogene by modulating the AKT/AMPK/mTOR pathway. Through transcriptome sequencing to identify downstream targets of XTP8, we found that XTP8 influences the expression of Caldesmon (CALD1) at both transcriptional and translational levels. CALD1 can be considered a downstream target of XTP8. The collaborative action of XTP8 and CALD1 activates the AKT/AMPK/mTOR pathway, regulating EMT to promote ovarian cancer progression. Inhibiting this signaling axis might represent a potential therapeutic target for ovarian cancer.

Kynurenine in IDO1high cancer cell-derived extracellular vesicles promotes angiogenesis by inducing endothelial mitophagy in ovarian cancer

BackgroundMitophagy, a prominent cellular homeostasis process, has been implicated in modulating endothelial cell function. Emerging evidence suggests that extracellular vesicles (EVs) participate in intercellular communication, which could modulate tumor angiogenesis, a hallmark of ovarian cancer (OC) progression. However, the underlying mechanisms through how EVs regulate endothelial mitophagy associated with tumor angiogenesis during OC development remain obscure.MethodsThe effect of cancer cell-derived EVs on endothelial mitophagy and its correlation with tumor angiogenesis and OC development were explored by in vitro and in vivo experiments. Multi-omics integration analysis was employed to identify potential regulatory mechanisms of cancer cell-derived EVs on endothelial mitophagy, which is involved in tumor angiogenesis associated with OC development. These insights were then further corroborated through additional experiments. An orthotopic OC mouse model was constructed to assess the antiangiogenic and therapeutic potential of the Indoleamine 2,3 dioxygenase-1 (IDO1) inhibitor.ResultsCancer cell-derived EVs promoted tumor angiogenesis via the activation of endothelial mitophagy, contributing to the growth and metastasis of OC. The aberrantly high expression of IDO1 mediated abnormal tryptophan metabolism in cancer cells and promoted the secretion of l-kynurenine (L-kyn)-enriched EVs, with associated high levels of L-kyn in EVs isolated from both the tumor tissues and patient plasma in OC. EVs derived from IDO1high ovarian cancer cells elevated nicotinamide adenine dinucleotide (NAD +) levels in endothelial cells via delivering L-kyn. Besides, IDO1high ovarian cancer cell-derived EVs upregulated sirt3 expression in endothelial cells by increasing acetylation modification. These findings are crucial for promoting endothelial mitophagy correlated with tumor angiogenesis. Notably, both endothelial mitophagy and tumor angiogenesis could be suppressed by the IDO1 inhibitor in the orthotopic OC mouse model.ConclusionsTogether, our findings unveil a mechanism of mitophagy in OC angiogenesis and indicate the clinical relevance of EV enriched L-kyn as a potential biomarker for tumorigenesis and progression. Additionally, IDO1 inhibitors might become an alternative option for OC adjuvant therapy.Graphical

Intraoperative Ketorolac and Outcomes after Ovarian Cancer Surgery.

Surgery is the cornerstone of ovarian cancer treatment. However, surgery and perioperative inflammation have been described as potentially pro-metastagenic. In various animal models and other human cancers, intraoperative administration of non-steroidal anti-inflammatory drugs (NSAIDs) appears to have a positive impact on patient outcomes. In this unicentric retrospective study, we provide an exploratory analysis of the safety and potential benefit of intraoperative administration of ketorolac on the outcome of patients undergoing surgery for ovarian cancer. The study population included all patients who were given a diagnosis of ovarian, fallopian tube or peritoneal cancer by the multidisciplinary oncology committee (MOC) of the Cliniques universitaires Saint-Luc between 2015 and 2020. We included 166 patients in our analyses, with a median follow-up of 21.8 months. Both progression-free survival and overall survival were superior in patients who received an intraoperative injection of ketorolac (34.4 months of progression-free survival in the ketorolac group versus 21.5 months in the non-ketorolac group (p = 0.002), and median overall survival was not reached in either group but there was significantly higher survival in the ketorolac group (p = 0.004)). We also performed subgroup analyses to minimise bias due to imbalance between groups on factors that could influence patient survival, and the group of patients receiving ketorolac systematically showed a better outcome. Uni- and multivariate analyses confirmed that administration of ketorolac intraoperatively was associated with better progression-free survival (HR = 0.47 on univariate analysis and 0.43 on multivariate analysis, p = 0.003 and 0.023, respectively). In terms of complications, there were no differences between the two groups, either intraoperatively or postoperatively. Our study has shown a favourable association between the use of ketorolac during surgery and the postoperative progression of ovarian cancer in a group of 166 patients, without any rise in intra- or postoperative complications. These encouraging results point to the need for a prospective study to confirm the benefit of intraoperative administration of ketorolac in ovarian cancer surgery.

TOP2A modulates signaling via the AKT/mTOR pathway to promote ovarian cancer cell proliferation

ABSTRACT Ovarian cancer (OC) is a form of gynecological malignancy that is associated with worse patient outcomes than any other cancer of the female reproductive tract. Topoisomerase II α (TOP2A) is commonly regarded as an oncogene that is associated with malignant disease progression in a variety of cancers, its mechanistic functions in OC have yet to be firmly established. We explored the role of TOP2A in OC through online databases, clinical samples, in vitro and in vivo experiments. And initial analyses of public databases revealed high OC-related TOP2A expression in patient samples that was related to poorer prognosis. This was confirmed by clinical samples in which TOP2A expression was elevated in OC relative to healthy tissue. Kaplan-Meier analyses further suggested that higher TOP2A expression levels were correlated with worse prognosis in OC patients. In vitro, TOP2A knockdown resulted in the inhibition of OC cell proliferation, with cells entering G1 phase arrest and undergoing consequent apoptotic death. In rescue assays, TOP2A was confirmed to regulate cell proliferation and cell cycle through AKT/mTOR pathway activity. Mouse model experiments further affirmed the key role that TOP2A plays as a driver of OC cell proliferation. These data provide strong evidence supporting TOP2A as an oncogenic mediator and prognostic biomarker related to OC progression and poor outcomes. At the mechanistic level, TOP2A can control tumor cell growth via AKT/mTOR pathway modulation. These preliminary results provide a foundation for future research seeking to explore the utility of TOP2A inhibitor-based combination treatment regimens in platinum-resistant recurrent OC patients.

Abstract B107: Elucidating the influence of long-chain fatty acids on ovarian cancer progression

Abstract Objective: High-fat diets have been associated with cancer progression. Yet, studies indicate that the effects can differ based on the type of fat involved, such as saturated versus unsaturated fatty acids. Uncovering the role of fatty acids may help guide nutrition and provide dietary therapy for cancer patients. In this study, we investigated the effect of common long-chain fatty acids, stearic acid (SA) and oleic acid (OA), on ovarian cancer (OC). Methods: We evaluated the cytotoxicity of SA and the effects of OA using IC50, a 72-hour proliferation assay, flow cytometry, and western blot. The concentration of fatty acids within the tumor was measured using liquid chromatography-mass spectrometry (LC/MS). CAY10566 was used to inhibit SCD1, the enzyme that converts SA to OA. In vivo, tumor growth was analyzed in human OC cell lines and patient-derived xenografts (PDX) using a mouse model fed with a normal diet (ND), an SA-rich diet, or an OA-rich diet combined with CAY10566. The SA-rich diet, which we specially created, had a stearic acid concentration of 33%. Results: SA displayed prominent cytotoxicity compared to other fatty acids. SA dose-dependently increased unfolded protein response (UPR) marker expression. Adding 1μM CAY10566 increased intracellular SA, decreased OA, and reduced IC50 to 20μM (p<0.05). CAY10566 significantly enhanced the cytotoxicity of SA, but the addition of exogenous OA canceled the increase in cell toxicity and UPR marker expression induced by SA (p<0.05). In vivo, tumor growth of OC cell lines and PDXs was significantly suppressed in the SA-rich with CAY10566 group compared to the ND group (p<0.05), while this suppression was nullified in the OA-rich with CAY10566 group. As confirmed by LC/MS, the stearic acid concentration significantly increased in the SA-rich group. Immunohistochemistry demonstrated that CHOP, gH2AX, and caspase-3 expression significantly increased in the SA-rich with CAY10566 group and dramatically decreased in the OA-rich with CAY10566 group (p<0.01). Conclusion: An ectopic supply of SA inhibits OC growth via UPR, while OA counteracts this effect. Creating a Stearate-rich/Oleate-limited environment through diet might affect tumor growth in vivo. Dietary content may greatly contribute to altering function in cancer. Citation Format: Jumpei Ogura, Koji Yamanoi, Mana Taki, Ryusuke Murakami, Ken Yamaguchi, Junzo Hamanishi, Masaki Mandai. Elucidating the influence of long-chain fatty acids on ovarian cancer progression [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 B107.

Abstract B111: Mechanism-informed photochemical strategies to overcome fluid shear stress-induced platinum resistance in ovarian cancer

Abstract Background: Over 75% of patients with disseminated ovarian cancer develop resistance to platinum-based chemotherapies (carboplatin or cisplatin). Patients with a high volume of malignant ascites or excessive fluid buildup in the peritoneum are more likely to present with primary platinum-resistant disease. It is hypothesized that the physical forces generated by ascites may contribute to the dissemination and progression of ovarian cancer. Our research group has shown that fluid shear stress (FSS) induces carboplatin resistance and a motile and aggressive phenotype in monolayer cultures and 3D models for adherent ovarian cancer. In this study, the effects of FSS on treatment response to cisplatin and doxorubicin were examined. The latter is used to manage recurrent platinum-resistant disease. Changes in mitochondrial function under FSS as they relate to platinum resistance were also characterized. Finally, the use of photodynamic therapy (PDT), which utilizes 690 nm light and a clinical photosensitizer benzoporphyrin derivative (BPD) to locally generate cytotoxic reactive molecular species as a means of overcoming FSS-induced platinum resistance, was explored. Methods: Human epithelial ovarian adenocarcinoma cells OVCAR-3 and Caov-3 (ATCC) were cultured in tissue culture plates (static culture) or chamber slides (ibidi) connected to a perfusion pump for 48 h (flow rate: 0.11 mL/min, shear stress: 0.41 dyn/cm2). Cells in static and flow cultures were exposed to cisplatin, doxorubicin, BPD-PDT or combinations thereof and survival fractions were measured 72 h post-treatment. Mitochondrial membrane potential was measured using JC-1 fluorescence assay, and mitochondrial DNA (mtDNA) copy number was quantified using qPCR. ATP content per cell was measured with a CellTiterGlo luminescence assay. Results: OVCAR-3 and Caov-3 cells grown under FSS developed significant resistance to cisplatin. Specifically, 3.13 µM cisplatin induced a 50% decrease in the survival fraction in OVCAR-3 static cultures but failed to decrease the survival fraction under flow. In contrast to these findings with platins, no resistance to doxorubicin was observed under flow. Evaluation of the mitochondrial function revealed increased ATP content and mtDNA copy number in flow cultures, suggesting that increased mitochondrial activity may contribute to platinum resistance. Finally, low-dose BPD-PDT (IC10, 0.15 J/cm2) enhanced the efficacy of cisplatin in OVCAR-3 cells under flow, indicating that PDT is a viable strategy to sensitize tumors exposed to FSS to platinum-based chemotherapy. Conclusions: Our data suggest that ovarian cancer cells that acquired resistance to platinum due to FSS remain sensitive to doxorubicin. Changes in mitochondrial function, including increased ATP content per cell and mtDNA copy number, have been identified as potential contributing factors to platinum resistance under FSS. Finally, low-dose BPD-PDT can be used to re-sensitize cells to cisplatin and overcome platinum resistance. Citation Format: Marta Overchuk, Brittany P. Rickard, Justin Tulino, Frances S. Ligler, Imran Rizvi. Mechanism-informed photochemical strategies to overcome fluid shear stress-induced platinum resistance 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 B111.

Abstract PR-008: Follicular fluid aids in cell adhesion, spreading and shows an age-dependent effect on DNA damage in fallopian tube epithelial cells

Abstract Ovarian cancer is the 5th leading cause of cancer related death in women with a low 5-year survival rate. Ovarian cancer is rarely detected early, and likely arises from the fimbriated end of the fallopian tube epithelium (FTE). There is a correlation between ovarian cancer and ovulation whereby ovulation suppression through use of oral contraception or pregnancy reduces the risk of ovarian cancer. Despite the association of ovarian cancer with ovulation, due to the lack of early detection methods, the disease typically presents as late stage, metastatic cancer in post-menopausal women who are no longer ovulating. The goal of this study was to understand how ovulation and the process of aging interact to provide a permissive environment for ovarian cancer initiation and progression in the FTE. The process of ovulation releases follicular fluid and induces the DNA damage response pathway in the FTE, but the role of aging on FTE exposure to follicular fluid has not been tested. De-identified follicular fluid samples were collected from 14 women (7 reproductively young (29-35 years) and 7 reproductively aged (40-44 years)) undergoing ART (Assisted Reproductive Technology) through the Northwestern University Reproductive Tissue Library (NU-RTL). We found that follicular fluid caused DNA damage and lipid oxidation in an age-dependent manner and cell proliferation in a dose-dependent manner in FTE cells. Interestingly, follicular fluid disrupted FTE spheroid formation and instead stimulated attachment and growth on ultra-low attachment plates. Follicular fluid when coated on the surface of the ultra-low plates enhanced FTE cell adhesion, spreading and proliferation. Proteomics analysis of the follicular fluid identified vitronectin, a glycoprotein as the factor responsible for FTE cell attachment and spreading. Overall, this study demonstrated that aging contributed to lipid oxidation and DNA damage of FTE cells and identified vitronectin in the follicular fluid as a protein factor that facilitates FTE cells to detach from 3D spheroids and spread on low attachment surfaces. Citation Format: Amrita Salvi, Wenping Li, Stephanie M. Cologna, Mary Ellen Pavone, Francesca E. Duncan, Joanna E. Burdette. Follicular fluid aids in cell adhesion, spreading and shows an age-dependent effect on DNA damage in fallopian tube epithelial 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 PR-008.

Abstract A088: Tumor innervation as a novel driver of ovarian cancer progression

Abstract One of the main challenges currently faced in ovarian cancer treatment is that the primary platinum/taxane therapy used to treat patients does not meaningfully extend survival. The overall survival for ovarian cancer patients with advanced disease is less than 30% with most patients recurring within 5 years of initial therapy. Once resistant disease develops there are few second line therapy options, which inevitably leads to disease progression. Thus, there is a critical need to identify new therapies that can overcome ovarian cancer chemoresistance and produce meaningful increases in patient survival. In recent years, new efforts have focused on targeting the tumor microenvironment (TME), the complex mixture of non-cancer cells that surround and support the cancer cells within the tumor. Different strategies have evolved to target the TME, such as immune checkpoint inhibitors or angiogenesis inhibitors. However, these TME targeting therapies have limited effect when used to treat ovarian cancer patients. Most ovarian tumors have a microenvironment that is highly immunosuppressive and do not respond or are resistant to angiogenesis inhibitors. Thus, new TME targeting therapies must be developed that can induce a therapeutic effect in ovarian tumors and can be used to treat most ovarian cancer patients. A novel TME component ripe for therapeutic targeting are the nerve fibers that infiltrate tumors in a process termed tumor innervation. Recent studies in several cancers have shown that tumor innervation can promote tumor growth/metastasis. However, in ovarian cancer the role of innervation in promoting cancer progression remains undefined. Here we show that Transient Receptor Potential cation channel subfamily V member 1 (TRPV1)+ sensory innervation plays a significant role in driving ovarian cancer growth and metastasis. Analysis of patient samples shows that sensory nerve fiber innervation is much higher in ovarian tumors vs benign reproductive tissue. In addition, ablation of TRPV1 sensory nerve fibers in vivo causes reduced tumor burden and prolongs survival in a syngeneic mouse model of ovarian cancer metastasis. Taken together, our results establish TRPV1+ sensory innervation as a novel driver of ovarian cancer growth/metastasis and a potential therapeutic target for ovarian cancer treatment. Citation Format: Matthew Knarr, Hunter Reavis, Timothy Lippert, Priyanka Rawat, Paola Vermeer, Ronny Drapkin. Tumor innervation as a novel driver of ovarian cancer progression [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 A088.

Abstract A072: Altering the ovarian cancer tumor microenvironment using car t cell therapy

Abstract Ovarian cancer accounts for 12,810 deaths per year in the USA, making it the deadliest gynecologic malignancy. Unfortunately, patients who are resistant to standard of care treatments have very limited effective therapeutic options. Immunotherapies are an emerging class of treatments that utilize a patient’s immune system to recognize and destroy tumor cells and have resulted in dramatic responses in many hematologic malignancies. In particular, reprograming patient T cells to recognize specific surface antigen(s) known as chimeric antigen receptor (CAR) T cell therapy, has provided both pediatric and adult patients with relapsed or treatment-unresponsive hematologic malignancies novel and potentially curative treatment options. CAR T cell therapy received FDA approval in 2018 for the treatment of B cell leukemia, however despite significant efforts, has been largely ineffective in solid malignancies. This is due in part to the complex solid tumor immune microenvironment (TME) and how it may change in response to therapies. For example, there is evidence that an FDA approved treatment for ovarian cancer called poly(ADP) ribose polymerase inhibitors (PARP; PARPi) leads to increased immune cell infiltration and cancer sensitivity to immunotherapies. This proposal will delineate the immune composition of the ovarian cancer TME using mouse models that closely recapitulate ovarian cancer progression and examine the impact of CAR T cells on the TME. We will utilize mouse ovarian cancer models that are sensitive and resistant to PARP inhibition. The information derived from these studies will provide a better understanding of the evolution of ovarian cancer TME and provide insight on how CAR T cells may alter the TME. Ultimately, we hope this work will lead to the development of safer and more effective therapeutic options for ovarian cancer patients. Citation Format: Alexandra N. McMellen, Michael S. Leibowitz. Altering the ovarian cancer tumor microenvironment using car t cell therapy [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 A072.

Abstract B002: Exploiting JAK/STAT signaling to inhibit highly advanced and resistant forms of ovarian cancer

Abstract Ovarian cancer is the most fatal of all female reproductive cancers due to its late detection, aggressive nature, and propensity to develop resistance to current standards of care. Despite initial responses to first line platinum- and paclitaxel-based chemotherapies, >70% of ovarian cancers recur with increasingly resistant disease. Targeted therapies, including PARP-inhibitors (PARPi) and VEGF-inhibitors, are being included in the front-line setting; and while they have improved progression-free survival in a subset of patients, they have thus far failed to improve overall survival in patients without specific genetic signatures. With the broad uptake of PARPi, PARPi-resistance is becoming common. Once resistance develops, nearly all patients die of their disease and there is an obvious need to elucidate the basis for chemotherapy- and PARPi-resistance and devise novel approaches to overcome resistance. Using a small molecule drug screen, we identified lestaurtinib, a known tyrosine kinase inhibitor as a potent inhibitor of treatment naive and highly advanced models of ovarian cancer. Lestaurtinib was originally developed to target FLT3, a protein not expressed in any ovarian cancer models we’ve tested. To identify lestaurtinib targets, we preformed phospho-proteomics in parallel with RNAseq and discovered the JAK/STAT signally pathway as a top hit. We confirmed that essential components of JAK/STAT signaling are constitutively activated in chemotherapy- and PARPi-resistant cells, suggesting that induction of this pathway may drive resistance. Importantly, we found that lestaurtinib-sensitive patient-derived-xenografts (PDXs) exhibited higher expression of multiple JAK/STAT signaling pathway members compared to PDXs that did not respond to lestaurtinib. Genetic knockdown of STAT1 and STAT3 via siRNA, or knockout via CRISPR/Cas9, resulted in significant growth inhibition of sensitive and resistant models, confirming their importance in maintaining cell viability and progression. Combining lestuartinib with standard-of-care cisplatin or olaparib, a PARPi, was shown to be synergistic in multiple models, indicating that pharmacological inhibition of JAK/STAT signaling has the potential to alleviate drug resistance. Finally, we assessed a panel of JAK/STAT inhibitors that interfere at various levels of the pathway and found profound differences in their ability to block STAT-phosphorylation and inhibit cell proliferation. Thus, it is critical to further define the mechanisms by which these drugs function to selectively suppress JAK/STAT signaling in order to elucidate specific nodes of the pathway that drive ovarian cancer progression. Ongoing studies are aimed at identifying the unique roles of STAT1 and STAT3, the specific contributions of their tyrosine and serine phosphorylation, and the relevance of up-/down-stream mediators of the JAK/STAT pathway on ovarian cancer cell growth with the goal of informing future clinical trials. Citation Format: Esther Rodman, Michael Emch, Archit Bajaj, Xiaojia Tang, Xiaonan Hou, Scott Kaufmann, Krishna Kalari, John Weroha, John Hawse. Exploiting JAK/STAT signaling to inhibit highly advanced and resistant forms 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 B002.

Abstract A105: Untangling the effect of ascites in shaping high grade serous ovarian cancer progression

Abstract High Grade Serous Ovarian Cancer (HGSOC) is the eighth cause of cancer-related mortality worldwide. Progress in eradicating this disease has been hampered by several factors, including the uncertainty about its tissues of origin, late diagnosis coupled to early dissemination through accumulation of ascitic fluid and extensive inter-patient variability. While being histopathologically homogeneous, HGSOC is characterized by several layers of heterogeneity that require the development of ad hoc research strategies and to focus on specific scales in order to deconvolve HGSOC pathogenetic mechanisms. In this context, our lab has previously shown that HGSOC can be derived both from the distal tract of the fallopian tube (fallopian tube epithelium, FTE) and the ovarian surface epithelium (OSE), with a prognostic impact for the tissue of origin and origin-specific molecular phenotypes, including an immune-suppressive response in the more aggressive OSE-derived subtype (Lo Riso, Villa et al. 2020), pointing at the role of tumor microenvironment in shaping therapeutical response. Moreover, we have also shown the role of ascitic fluid in sustaining the generation of single cell-derived metastatic ovarian cancer spheroids (sMOCS), that enrich for cancer stem-like cells, and allowing to identify a consistent intra-patient variability in response to carboplatin treatment (Velletri, Villa, Cilli, Barzaghi et al. 2022). To understand the specific impact of the tumor microenvironment in shaping HGSOC complexity, here we show an experimental framework aimed at the identification of the downstream effect of ascites in shaping cellular and molecular features of HGSOC. Here we leverage a newly generated single cell transcriptomic atlas, encompassing 1.5 million cells from 79 patients derived from primary tumors, ascites and metastatic samples, to identify specific expression networks activated during the metastatization process. In parallel, we derive from bulk transcriptomic data the set of genes that are induced upon ascitic fluid supplementation in 2D and 3D in vitro models, that are coupled to model-specific phenotypes, including cell proliferation, stemness and invasiveness. These genes are then integrated in the single-cell derived metastasis-specific expression networks to identify the upstream regulators imputable to ascitic fluid exposure. The linked regulators and downstream effectors are then used to identify in the atlas cell populations whose expression landscape is directly affected by ascitic fluid. The identification of such cell populations will allow to highlight cell-to-cell interactions existing between i) different tumor subpopulations; ii) tumor and tumor-associated compartments, in both primary and metastatic samples, that can be ascribed to the presence of ascitic fluid. Moreover, the molecular characterization of these interacting populations will allow to identify novel targets, paving the way to the identification of novel therapeutical avenues for HGSOC patients. Citation Format: Pietro Lo Riso, Carlo Emanuele Villa, Bianca Barzaghi, Marta R. Sallese, Giulia Picco, Alessia Gatto, Ugo Cavallaro, Giuseppe Testa. Untangling the effect of ascites in shaping high grade serous ovarian cancer progression [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 A105.

Abstract B069: Bone marrow-derived adipocytes promote ovarian cancer progression and metastasis

Abstract B069: Bone marrow-derived adipocytes promote ovarian cancer progression and metastasis

RNA m5C modification upregulates E2F1 expression in a manner dependent on YBX1 phase separation and promotes tumor progression in ovarian cancer

5-Methylcytosine (m5C) is a common RNA modification that modulates gene expression at the posttranscriptional level, but the crosstalk between m5C RNA modification and biomolecule condensation, as well as transcription factor-mediated transcriptional regulation, in ovarian cancer, is poorly understood. In this study, we revealed that the RNA methyltransferase NSUN2 facilitates mRNA m5C modification and forms a positive feedback regulatory loop with the transcription factor E2F1 in ovarian cancer. Specifically, NSUN2 promotes m5C modification of E2F1 mRNA and increases its stability, and E2F1 binds to the NSUN2 promoter, subsequently reciprocally activating NSUN2 transcription. The RNA binding protein YBX1 functions as the m5C reader and is involved in NSUN2-mediated E2F1 regulation. m5C modification promotes YBX1 phase separation, which upregulates E2F1 expression. In ovarian cancer, NSUN2 and YBX1 are amplified and upregulated, and higher expression of NSUN2 and YBX1 predicts a worse prognosis for ovarian cancer patients. Moreover, E2F1 transcriptionally regulates the expression of the oncogenes MYBL2 and RAD54L, driving ovarian cancer progression. Thus, our study delineates a NSUN2-E2F1-NSUN2 loop regulated by m5C modification in a manner dependent on YBX1 phase separation, and this previously unidentified pathway could be a promising target for ovarian cancer treatment.

MiR-5590-3p inhibits the proliferation and invasion of ovarian cancer cells through mediating the Wnt/β-catenin signaling pathway by targeting TNIK.

MicroRNAs (miRNAs) are crucial regulatory molecules involved in diverse biological processes and human diseases, including ovarian cancer (OC). miR-5590-3p has been involved in multiple malignant solid tumors, but its exact role in the progression of OC is largely unknown. This study mainly focuses on how miR-5590-3p works in OC and illuminating the underlying mechanism. We found that miR-5590-3p was significantly downregulated in human OC cell lines and patient tissues. Cell counting 8 (CCK-8) and Transwell assays proved that overexpression or inhibition of miR-5590-3p suppressed or promoted cell proliferation and cell invasion. Subsequently, TNIK was identified as a target of miR-5590-3p. Silence of TNIK by small interfering RNA (siRNA) reversed the increasing effect of miR-5590-3p inhibition on cell proliferation and invasion in OC cell lines. Furthermore, our results showed that the Wnt/β-catenin pathway was inhibited by its specific inhibitor XAV-939, but miR-5590-3p inhibitor and adenoviral TNIK overexpression vector (Ad-TNIK) reactivated the activation of Wnt/β-catenin signaling and increased cell malignancy. Lastly, tumorigenicity assay demonstrated that inhibition of miR-5590-3p increased tumor volume and weight in vivo. In conclusion, miR-5590-3p may function as a cancer suppressor gene in OC progression through the Wnt/β-catenin signaling by transcriptionally suppressing TNIK expression, which provides a potential therapeutic approach for ovarian cancer treatment.

RPL35A drives ovarian cancer progression by promoting the binding of YY1 to CTCF promoter.

Ovarian cancer is one of the most common gynaecological malignancies with poor prognosis and lack of effective treatment. The improvement of the situation of ovarian cancer urgently requires the exploration of its molecular mechanism to develop more effective molecular targeted drugs. In this study, the role of human ribosomal protein l35a (RPL35A) in ovarian cancer was explored invitro and invivo. Our data identified that RPL35A expression was abnormally elevated in ovarian cancer. Clinically, high expression of RPL35A predicted short survival and poor TNM staging in patients with ovarian cancer. Functionally, RPL35A knock down inhibited ovarian cancer cell proliferation and migration, enhanced apoptosis, while overexpression had the opposite effect. Mechanically, RPL35A promoted the direct binding of transcription factor YY1 to CTCF in ovarian cancer cells. Consistently, RPL35A regulated ovarian cancer progression depending on CTCF invitro and invivo. Furthermore, RPL35A affected the proliferation and apoptosis of ovarian cancer cells through PPAR signalling pathway. In conclusion, RPL35A drove ovarian cancer progression by promoting the binding of YY1 and CTCF promoter, and inhibiting this process may be an effective strategy for targeted therapy of this disease.

The selenoenzyme type I iodothyronine deiodinase: a new tumor suppressor in ovarian cancer.

The selenoenzyme type I iodothyronine deiodinase (DIO1) catalyzes removal of iodine atoms from thyroid hormones. Although DIO1 action is reported to be disturbed in several malignancies, no work has been conducted in high-grade serous ovarian carcinoma (HGSOC), the most lethal gynecologic cancer. We studied DIO1 expression in HGSOC patients [The Cancer Genome Atlas (TCGA) data and tumor tissues], human cell lines (ES-2 and Kuramochi), normal Chinese hamster ovarian cells (CHO-K1), and normal human fallopian tube cells (FT282 and FT109). To study its functional role, DIO1 was overexpressed, inhibited [by propylthiouracil (PTU)], or knocked down (KD), and cell count, proliferation, apoptosis, cell viability, and proteomics analysis were performed. Lower DIO1 levels were observed in HGSOC compared to normal cells and tissues. TCGA analyses confirmed that low DIO1 mRNA expression correlated with worse survival and therapy resistance in patients. Silencing or inhibiting the enzyme led to enhanced ovarian cancer proliferation, while an opposite effect was shown following DIO1 ectopic expression. Proteomics analysis in DIO1-KD cells revealed global changes in proteins that facilitate tumor metabolism and progression. In conclusion, DIO1 expression and ovarian cancer progression are inversely correlated, highlighting a tumor suppressive role for this enzyme and its potential use as a biomarker in this disease.

Follicular fluid aids cell adhesion, spreading in an age independent manner and shows an age-dependent effect on DNA damage in fallopian tube epithelial cells

Ovarian cancer (OC) is deadly, and likely arises from the fallopian tube epithelium (FTE). Despite the association of OC with ovulation, OC typically presents in post-menopausal women who are no longer ovulating. The goal of this study was to understand how ovulation and aging interact to impact OC progression from the FTE. Follicular fluid released during ovulation induces DNA damage in the FTE, however, the role of aging on FTE exposure to follicular fluid is unexplored. Follicular fluid samples were collected from 14 women and its effects on FTE cells was assessed. Follicular fluid caused DNA damage and lipid oxidation in an age-dependent manner, but instead induced cell proliferation in a dose-dependent manner, independent of age in FTE cells. Follicular fluid regardless of age disrupted FTE spheroid formation and stimulated attachment and growth on ultra-low attachment plates. Proteomics analysis of the adhesion proteins in the follicular fluid samples identified vitronectin, a glycoprotein responsible for FTE cell attachment and spreading.

TMED3 stabilizes SMAD2 by counteracting NEDD4-mediated ubiquitination to promote ovarian cancer.

Ovarian cancer is a major cause of death among cancer patients. Recent research has shown that the transmembrane emp24 domain (TMED) protein family plays a role in the progression of various types of cancer. In this study, we investigated the expression of TMED3 in ovarian cancer tumors compared to nontumor tissues using immunohistochemical staining. We found that TMED3 was overexpressed in ovarian cancer tumors, and its high expression was associated with poor disease-free and overall survival. To understand the functional implications of TMED3 overexpression in ovarian cancer, we conducted experiments to knockdown TMED3 using short hairpin RNA (shRNA). We observed that TMED3 knockdown resulted in reduced cell viability and migration, as well as increased cell apoptosis. Additionally, in subcutaneous xenograft models in BALB-c nude mice, TMED3 knockdown inhibited tumor growth. Further investigation revealed that SMAD family member 2 (SMAD2) was a downstream target of TMED3, driving ovarian cancer progression. TMED3 stabilized SMAD2 by inhibiting the E3 ligase NEDD4-mediated ubiquitination of SMAD2. To confirm the importance of SMAD2 in TMED3-mediated ovarian cancer, we performed functional rescue experiments and found that SMAD2 played a critical role in this process. Moreover, we discovered that the PI3K-AKT pathway was involved in the promoting effects of TMED3 overexpression on ovarian cancer cells. Overall, our study identifies TMED3 as a prognostic indicator and tumor promoter in ovarian cancer. Its function is likely mediated through the regulation of the SMAD2 and PI3K-AKT signaling pathway. These findings contribute to our understanding of the molecular mechanisms underlying ovarian cancer progression and provide potential targets for therapeutic intervention.