Abstract 2384: Hypoxia-induced exosomal miR-376c-3p promotes metastatic potential of ovarian cancer cells

Abstract Background: Hypoxia significantly impacts cancer progressions, in various types of solid tumors including ovarian cancer. Exosomes (30-150nm) secreted from cells in the hypoxic tumor microenvironment play a critical role in cancer progression through transferring functional proteins, mRNAs, and miRNAs as mediators of intercellular communication. However, the underlying mechanisms how cancer exosomes induced by hypoxia regulate cancer progressions remain elusive. This study aims to assess the effect of exosomes secreted from hypoxic cancer cells on the metastatic ability of ovarian cancer cells. Methods: Two ovarian cancer cell lines, Kuramochi and SKOV-3, were used. Exosomes from cancer cells cultured under normoxic or hypoxic conditions (normoxic or hypoxic exosomes) were isolated using Exoquick-TC kit and identified by nanoparticle tracking analysis, transmission electron microscopy, and western blotting. BCA assay was done to evaluate the concentration of exosomes. Normoxic or hypoxic exosomes were treated on ovarian cancer cells. Cell migration and invasion abilities were examined by wound healing assay and MatriGel invasion assay respectively. Furthermore, miRNA sequencing was performed to explore the miRNA profiling of hypoxic and normoxic exosomes. Results: The size of exosomes was ranging from 52nm to 121nm (mean diameter = 85nm). The quantity of hypoxic exosomes was significantly more than that of normoxic exosomes. Hypoxic exosomes increased the migration and invasion ability of kuramochi and SKOV-3 cells. In addition, hypoxic exosomes treatment on ovarian cancer cells up-regulated the expression of MMP-2 and Snail-1 at the protein level. MiRNA sequencing showed that miR-376c-3p was significantly upregulated in hypoxic exosomes in both ovarian cancer cell lines. Moreover, miR376c-3p enhanced migration and invasion ability of ovarian cancer cells, validated by miR376c-3p inhibitor and mimics. Conclusions: Taken together, our study suggests that miR376c-3p transferred by hypoxic exosomes could promote the metastatic potential of ovarian cancer cells by inducing MMP-2 and Snail-1. Citation Format: HyunA Jo, Wenyu Wang. Hypoxia-induced exosomal miR-376c-3p promotes metastatic potential of ovarian cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2384.