miR-141 Promotes Colon Cancer Cell Proliferation by Targeted PHLPP2 Expression Inhibitionn

Objective: Colon cancer (CC) is the third most common cancer with a high rate of incidence and mortality. Therefore, it is highly necessary to explore novel targets of CC. Methods: The miRNA-seq and RNA-seq data of CC were accessed from the TCGA database. Differential analysis was performed using the "edgeR" package to identify differentially expressed miRNAs (DE_miRNAs). The downstream target genes of the target miRNA were then predicted by miRNA target prediction databases to identify the target mRNA. Normal colon cell line CCD-18Co and CC cell lines HCT-116, HT-29, SW620 and SW480 were chosen, and qRT-PCR was conducted to detect miR-141 expression in these cell lines. qRT-PCR and Western blot were carried out to determine PHLPP2 mRNA and protein expression, respectively. Dual-luciferase reporter gene assay was performed to verify the targeting relationship between miR-141 and PHLPP2 3'UTR. CCK-8 assay and colony formation assay were carried out to detect cell proliferation. Meanwhile, tumor xenograft model in nude mice was constructed to assess CC cell tumorigenic ability in vivo. Results: miR-141 was markedly up-regulated in CC tissue. CC cell proliferation and in vivo tumorigenic ability were suppressed by miR-141 silencing but promoted by miR-141 over-expression. PHLPP2 was significantly down-regulated in cancer tissue. Dual-luciferase reporter gene assay indicated that miR-141 could bind to PHLPP2 3'UTR. PHLPP2 expression was noticeably elevated upon miR-141 deficiency but significantly inhibited upon miR-141 over-expression. CCK-8 and colony formation assay suggested that miR-141 facilitated CC cell proliferation by silencing PHLPP2. Conclusion: miR-141 promotes CC cell proliferation by targeted silencing PHLPP2.