miR-338-3p suppresses colorectal cancer proliferation and progression by inhibiting MACC1

Abstract

Colorectal cancer (CRC) is one of the most common malignancies worldwide. This study aimed to elucidate the clinicopathological significance of miR-338-3p and its association with metastasis-associated in colon cancer-1 (MACC1) in CRC. We evaluated miR-338-3p and MACC1 expression in CRC cell lines and analyzed the clinicopathological features of miR-338-3p in 98 samples of CRC tissues. Subsequent Western blot and cellular biological techniques, and xenograft mouse models were performed to investigate the biological role of miR-338-3p and its association with MACC1 in CRC. Our results show that miR-338-3p expression is lower in CRC cell lines and tissues than that in a human normal colonic epithelial cell line and adjacent normal colorectal tissue, respectively. miR-338-3p expression was significantly associated with histological differentiation, UICC stage, T classification, N classification, and M classification in 98 samples of CRC. The overall survival of CRC patients was significantly less in the low miR-338-3p expression group than in the high miR-338-3p expression group (p<0.01). miR-338-3p mimics suppressed cell proliferation, colony formation, migration, and invasion, but induced apoptosis in CRC cells. miR-338-3p inhibitor reversed these biological phenotypes. miR-338-3p mimics or inhibitor suppressed or increased MACC1 expression in HCT116 and SW620. miR-338-3p mimics reversed the effect of increased MACC1 expression induced by HCT116 with MACC1 over-expression plasmid. Increased cell proliferation, colony formation, and suppressed cell apoptosis caused by MACC1 over-expression were significantly reversed in HCT116 transfected with miR-338-3p mimics, respectively. Suppressed cell proliferation, colony formation, migration, invasion, and increased cell apoptosis caused by MACC1 knockdown were significantly reversed in SW620 transfected with miR-338-3p inhibitor, respectively. In vivo, miR-338-3p agomir significantly inhibited xenograft CRC tumor growth and reversed the effect of increased xenograft tumor growth induced from HCT116 with MACC1 overexpression. In conclusion, our data suggest that miR-338-3p suppresses CRC carcinogenesis and progression by inhibiting MACC1. Targeting miR-338-3p might be a novel treatment strategy for CRC.

Keywords: MACC1; colorectal cancer; miR-338-3p.