Expression and clinical significance of miR-17-5p in tumor tissues of patients with colorectal cancer

BACKGROUND: At present, there is a lack of novel biomarkers for the early diagnosis and targeted therapy of colorectal cancer (CRC). The current study investigated the expression of miR-17-5p in colorectal tumors and adjacent tissues, and examined the effects of miR-17-5p on the cellular growth of the colon cancer cell line HCT-116. METHODS: A total of 30 paired tissue specimens were obtained from patients with CRC who were admitted to the Department of General Surgery V of the First Affiliated Hospital, Gannan Medical College between December 2019 and January 2021. The clinical information for the corresponding patients was collated. Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) was performed to detect the expression of miR-17-5p in tumor tissues and the paracancerous tissues. The relationship between miR-17-5p and clinicopathology was analyzed. The CRC cell line HCT-116 was transfected with miR-17-5p mimics and inhibitors using liposomes. The effects of miR-17-5p on cell proliferation, invasion and migration, and apoptosis were determined using colon formation assays, transwell and scratch assays, and flow cytometry, respectively. The effects of miR-17-5p on CD44 (homing cell adhesion molecule), MMP2 (matrix metalloproteinase 2), BCL2 (B-cell lymphoma-2), BAX (BCL2-associated X), and E-cadherin protein and gene expression were investigated using Western blot and RT-qPCR, respectively. RESULTS: MiR-17-5p expression was higher in tumor tissues compared to the normal adjacent tissues. While miR-17-5p expression levels were unrelated to age nor gender, they were related to the degree of differentiation, stage, lymph node metastasis, and tumor size in patients with CRC. Upregulation of miR-17-5p promoted CRC cell proliferation, metastasis, and invasion, while inhibiting apoptosis. However, downregulation of miR-17-5p had the opposite effect. Furthermore, miR-17-5p upregulation increased E-cadherin, CD44, MMP2, and BCL2 expression while decreasing BAX expression, whereas miR-17-5p downregulation had the opposite effect. CONCLUSIONS: MiR-17-5p is highly expressed in tumor tissues and correlates with increased proliferation, invasion, and migration, as well as reduced apoptosis in HCT-116 cells. Indeed, miR-17-5p may be a potential indicator for the early diagnosis of CRC and may guide clinical targeted therapy.