Role of visfatin in promoting proliferation and invasion of colorectal cancer cells by downregulating SDF-1/CXCR4-mediated miR-140-3p expression.

OBJECTIVE Visfatin is significantly upregulated in colorectal cancer (CRC). However, its exact role in CRC progression and the regulatory mechanism involved in this process have not been fully illuminated. The aim of this study was to investigate the roles of visfatin in CRC progression and the potential molecular mechanism. MATERIALS AND METHODS In vitro, two CRC cell lines (DLD-1 and SW480) were transfected with visfatin, si-visfatin, and their control vectors. Some cells were transfected with miR-140-3p mimics or miRNA negative control. Cell Counting Kit-8 and transwell invasive assays were used to detect cell proliferation and invasion ability. Luciferase reporter assays were performed to confirm whether CXC motif chemokine receptor 4 (CXCR4) directly targets miR-140-3p. Western blotting and qRT-PCR analyses were respectively conducted to evaluate the protein and mRNA levels of stromal cell-derived factor-1 (SDF-1) and CXCR4. In vivo, DLD-1 cells transfected with visfatin construct or vector control were inoculated into nude mice. After 5 weeks, the mice were sacrificed, and the tumor nodules were weighed. The expression of visfatin, SDF-1, and CXCR4 in tumor tissues was detected via immunohistochemistry analysis. RESULTS In vitro, the transfection of visfatin promoted the proliferation and invasion of CRC cells, as well as upregulated the expression of SDF-1/CXCR4. MiR-140-3p directly targets the 3'untranslated region of CXCR4. MiR-140-3p expression was downregulated by treatment with visfatin, and miR-140-3p exerted similar effects to those of visfatin knockdown on the proliferation and invasion of CRC cells. In vivo, visfatin stimulated CRC tumor growth and downregulated miR-140-3p expression, whereas it upregulated SDF-1/CXCR4 expression. CONCLUSIONS Visfatin promotes CRC progression by downregulating the SDF-1/CXCR4-mediated expression of miR-140-3p both in vitro and in vivo.