Long noncoding RNA HCP5 contributes to epithelial-mesenchymal transition in colorectal cancer through ZEB1 activation and interacting with miR-139-5p.

Long noncoding RNAs (lncRNAs) play key roles in various malignancy pathogenesis. However, the mechanisms remain poorly understood in the development and progression of colorectal cancer (CRC). Here, we focused on the specific role of human leukocyte antigen (HLA) Complex P5 (HCP5) in CRC. Quantitative real-time PCR (qRT-PCR) analysis and western blot were used to assess the expression of HCP5 in CRC tissues. The association between the expressions of HCP5 and miR-139-5p was assessed by Pearson's correlation analysis. The prognosis of CRC patients was analyzed by Kaplan-Meier survival analysis. Specific siRNAs were stably transfected into CRC cells with lentivirus approaches. The proliferative, migrative and invasive capacities of CRC cells were detected by Transwell, MTT and scratch assay, respectively. Dual-luciferase assay was performed to measure miR-139-5p-targeted relationship with lncRNA HCP5. HCP5 overexpression and of miR-139-5p downregulation were dramatically correlated with low TNM stage, poor differentiation, low tumor depth invasion in CRC patients (P < 0.05). Besides, HCP5 overexpression or ZEB1 knockdown repressed Snail family transcriptional repressor (SNAI) and vimentin expressions, upregulated E-cadherin expression, and inhibited cell proliferation and metastasis (P < 0.05). Moreover, luciferase reporter assay demonstrated that miR-139-5p was a directly target of HCP5 (P < 0.05). Overall, the present study indicated that HCP5 played a key regulator in CRC development and progression by targeting HCP5/miR-139-5p/ZEB1 axis, which may serve as a novel therapeutic target for CRC therapy.