Abstract 2359: MicroRNA 494-5p acts as tumor suppressor in colorectal cancer by targeting JAK1

Recently, we have characterized the metastatically relevant microRNA landscape by comparing microRNA (miR) expression between human colorectal metastasis and matched primary tumors and normal tissues (Mudduluru et. al. Cancer Res. 2015; PMID: 26069251). One of these, miR-494-5p, was deregulated already in primary tumors. In vitro invasion and migration (Boyden chamber and Matrigel) assays of cultured colorectal cancer cells were significantly reduced after miR-494-5p overexpression (mimic). Conversely, this was abolished by anti-miR-494-5p as an inhibitor. Overexpression of miR-494-5p in cell lines showed a significant reduction in cellular proliferation, which was reversed upon inhibitor co-transfection in a time dependent manner. In silico analysis suggested an interaction of miR-494-5p with the 3´UTR of JAK1. Accordingly, an overexpression of miR-494-5p in cultured colon cancer significantly reduced luciferase activity of a reporter plasmid containing the wild type JAK1-39UTR, which was abolished when the miR-494-5p seed sequence was mutated to prevent miR-494-5p binding, suggesting a physical interaction and translational repression of JAK1 by miR-494-5p. Furthermore, overexpression of miR-494-5p led to a significant reduction of JAK1 expression in colorectal cancer cell lines in a time dependent manner, which was abolished by co-transfecting a specific anti-miR-494-5p as an inhibitor. Taken together, our preliminary data suggests that miR-494-5p inhibits the expression of JAK1 as a direct molecular target via specific interaction at the JAK1-39UTR. Additionally, miR-494-5p is capable of reducing proliferation, migration, and invasion, suggesting miR-494-5p as an early tumor suppressor molecule in colorectal cancer. Citation Format: Heike Allgayer, Nitin Patil, Omar Abdelrahim, Joerg H. Leupold. MicroRNA 494-5p acts as tumor suppressor in colorectal cancer by targeting JAK1 [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 2359.