Inhibition of the mToR pathway with everolimus can modulate heat shock genes and ERCC1 gene expression and improves outcomes on serous ovarian cancer in HIPEC in vitro model.

Abstract

e17541 Background: Worldwide, epithelial ovarian cancer accounts for a significant percentage of malignancies and is the most lethal neoplasm of the gynecological system, mainly due to silent manifestation and late diagnosis. Predominantly, around 70% of newly diagnosed women with epithelial ovarian cancer have the locally advanced or metastatic stage (III/IV). The extensive peritoneal dissemination of epithelial ovarian cancer might occur at the time of primary tumor diagnosis or related to disease relapse after previous treatment. Therefore, understanding the dynamic of peritoneal dissemination is of utmost importance, as peritoneal carcinomatosis is frequently associated with disease morbidity and mortality. Methods: In this study, we cultivated ovarian cancer cells using the OV-90 cell line (high-grade serous) and assessed citoxicity using MTT assay. Initially, the ovarian cancer cells were treated with everolimus 18 nM (37˙C) for 24 hours for both experimental and control groups. Subsequently, two experimental groups were treated with cisplatin in normothermia (Group 1) and hyperthermia (Group 2) (37˙C and 41˙C, respectively) while the control group was treated with phosphate-buffered saline solution 1X at 37˙C (Group 3) and 41˙C (Group 4) for 24 hours. After the first treatment, we re-supplemented each group under the same beforementioned conditions and incubated it for three additional hours. Moreover, the RNA extracts of each sample set were submitted to RT-PCR for the obtention of the qRT-PCR material. Lastly, we compared the expression of the ERCC1 gene and heat shock genes amongst the different intervention groups. Results: There statistical difference concerning cytotoxicity between treatment with everolimus and heated cisplatin versus treatment with everolimus and cisplatin in normothermia. We observed that the ERCC1 and TRAP 1 genes were downregulated in OV-90 cell lines under heated conditions compared to the normothermia group. Conclusions: The use of everolimus in HIPEC in vitro model increases the cytotoxic response and suggest that inhibition of the mTOR pathway modulates the expression of heat shock genes e ERCC1 gene improving outcomes. Nevertheless, there is still a need for studies evaluating the effectiveness of everolimus in preclinical trials under hyperthermic conditions.