PO-321 MicroRNA-145 and COX2 levels are regulated by nerve growth factor (NGF) in epithelial ovarian cancer

Abstract

IntroductionIn many type of cancer, including epithelial ovarian cancer (EOC), nerve growth factor (NGF) and its high affinity receptor TRKA are over-expressed and also are involved in proliferation and angiogenesis. On the other hand, many inflammatory molecules such as cyclooxigenase-2 (COX-2) and prostaglandins (PGE2) are over-expressed in cancer and also involved in the progression of cancer. Besides, a deregulation of some miRs expression has been described in EOC including miR-145 among others. The relationship of NGF-mirRs-COX2 in EOC has not been studied. Then, the aim of this work was to evaluate COX-2 and miR-145 levels in EOC progression and the changes of COX-2 and miR-145 levels by NGF action in epithelial ovarian cancer cell line (A2780). Also we evaluated COX-2 levels by Western-Blot after over-expression of miR-145 in A2780 cell line.Material and methodsThirty human ovarian tissues (normal, tumour and cancer) were obtained from Obstetrics and Gynaecology Department, Clinical Hospital, University of Chile and also from National Institute of Cancer with written consent and authorised by Ethic Committee of the Institutions. The COX-2 levels in tissues and cells were measured by RT-PCR, IHQ, and Western-Blot and miR-145 was measured by qPCR. Cells A2780 were stimulated with NGF (100 and 150 ng/ml) to measure COX-2 and miR-145 levels. Besides, over-expression of miR-145 was done by transfection assays with lipofectamine-2000 to evaluate cellular invasion and also transduction assays with lenti-virus in order to evaluate COX-2 levels by Western-Blot in A2780 cell line.Results and discussionsIt was found a significant decrease of miR-145 levels in EOC tissues compared with tumour tissues and normal ovarian tissues (p<0.05). On the other hand, a significant increase of COX-2 levels was found in EOC tissues compared with tumours and normal tissues (p<0.05). The activation of TRKA receptor by NGF induced a significant decrease of miR-145 levels (p<0.05) and a significant increase of COX-2 levels (p<0.05) in epithelial ovarian cancer cell line A2780. When miR-145 was over-expressed in A2780 cells, a significant decrease of COX-2 levels was found (p<0.05). These results support the role of NGF in the regulation of miRs and inflammatory molecules in EOC.ConclusionMicroRNA-145 acts as tumour suppressor microRNA in ovarian cancer and these results suggest that miR-145 could be a good therapy for EOC.This work was supported by Grant: Fondecyt 1160139 to CR and ACCDIS - Conicyt-Fondap 15130011