Abstract 3026: Galunisertib inhibits ovarian cancer cell fibrosis and metastasis in vitro

Abstract

Abstract Background: In ovarian cancer (OC), the intraperitoneal fibrosis that accompanies metastasis is a common scenario and associated with significant morbidity and gut dysfunction. Accumulating evidences indicate that Transforming Growth Factor β (TGF-β) signaling pathway plays a key role in cancer associated fibrosis and metastasis. Several TGF-β inhibitors, including Galunisertib (LY2157299) which is a TGF-β receptor I inhibitor, are currently in clinical trials for fibrosis-related diseases and cancer. Our hypothesis is that targeted anti-cancer therapies can block the growth and spread of cancer or specifically address the fibrosis accompanying metastatic peritoneal cancer. In this study, we investigated the efficacy of Galunisertib in inhibiting OC fibrosis and metastasis in vitro. Methods: Five OC cell lines, including SKOV3ip, HeyA8, OVCAR8, OV2008, and PEO4, and one cancer-associated fibroblast (CAF) cell line, TRS3, were tested in this study. We utilized a co-culture system that has successfully been used to study the interactions between cancer cells and local environment, including CAFs. Twenty-three candidate TGF-β signaling- and fibrosis-related genes were selected based on previous studies. RNA and protein from both fibroblast cells and OC cells were collected for RT-qPCR and western blot analysis. MTT assay, Wound healing assay and Matrigel invasion assay were used to study OC cell proliferation, migration and invasion. Chou-Talalay assays were performed to study the interactions between Galunisertib and Carboplatin and Paclitaxel. Results: RT-qPCR results showed that Galunisertib treatment suppresses the expression of both TGF-β receptor I and TGF-β1 which is the most abundant isoform of TGF-β in OC. Western blot results showed that Galunisertib treatment reverses the TGF-β1-induced SMAD2/3 phosphorylation, confirming the efficacy of Galunisertib in TGF-β signaling pathway blockage. Intriguingly, Galunisertib treatment inhibits the expression of candidate fibrosis-related genes, like ACTA2, TIMP3, COL5A1, COL11A1, and VCAN in both OC and CAF cells. Would healing and Transwell invasion assay also demonstrated that Galunisertib treatment effectively reduces both basal and TGF-β1-induced cell migration and invasion (p<0.05). MTT assay showed that Galunisertib is able to inhibit the proliferation of both OC and CAFs cells with IC50 values range from 100-400 μm. Additionally, Galunisertib shows strong synergistic effects with both Carboplatin and Paclitaxel in Chou-Talalay assays. Conclusion: Galunisertib treatment suppresses the expression of TGF-β-dependent fibrosis-related genes from OC cell lines and CAFs. Coincident with this inhibition of fibrosis related genes, galunisrtib reduces cell proliferation, migration, and invasion. These data suggest that targeting the TGF-β pathway is a viable therapeutic approach to reduce both symptoms related to OC-related fibrosis and cancer metastasis in OC. Citation Format: Qing Zhang, William A. Cliby. Galunisertib inhibits ovarian cancer cell fibrosis and metastasis in vitro. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3026.