miR-17-5p promotes the invasion and migration of colorectal cancer by regulating HSPB2

Abstract Background: MicroRNA (miRNA) can affect tumor progression by regulating cell proliferation, apoptosis and metastasis. After miRNA microarray chip analysis of colorectal cancer (CRC) tissues and adjacent normal tissues, a significant upregulation of miR-17-5p expression was found in CRC tissues. However, the underlying mechanism of miR-17-5p in CRC is still unclear.Methods: The levels of miR-17-5p in 47 paired CRC and adjacent normal tissue samples were determined by quantitative real-time PCR (qRT-PCR). CCK-8, colony formation, flow cytometry and transwell assays were used to explore the biological effects of miR-17-5p on CRC cells. In addition, the transcriptome sequencing and miRNA target prediction software were employed to identify targets of miR-17-5p. Luciferase reporter detection was used to demonstrate the direct binding of target genes by miR-17-5p. The rescue experiment was conducted to investigate the biological function of target genes and regulatory mechanism of miR-17-5p on target genes.Results: The expression of miR-17-5p was significantly higher in CRC tissues than in adjacent normal tissues. In CRC group, the expression of miR-17-5p in cancer tissues with lymph node metastasis was higher compared with those without lymph node metastasis. Overexpression of miR-17-5p inhibited CRC cell apoptosis, as well as promoting proliferation, migration and invasion. We hypothesized that HSPB2 might be a target gene of miR-17-5p and validated for the first time that miR-17-5p binds directly to the 3’-UTR of HSPB2. In the rescue experiment, the tumor suppressive effect of HSPB2 was detected and miR-17-5p could promote cell proliferation, migration and invasion by targeting HSPB2.Conclusion: MiR-17-5p promotes invasion and migration by inhibiting HSPB2 in CRC, thereby implicating its potential as a novel diagnostic biomarker and therapeutic target for CRC.