Study on the mechanism of lncRNA HCG18 promoting the proliferation, migration and invasion of osteosarcoma cells by targeting miR-34b-5p/FOXP1 axis

ObjectiveTo investigate the effect and possible mechanism of long non-coding RNA (lncRNA) human leukocyte antigen complex 18 (HCG18) on the proliferation, migration and invasion of osteosarcoma cells.

MethodsForty-seven cases of osteosarcoma tissues and corresponding adjacent tissues were collected. RT-qPCR was used to detect the expression of HCG18 and miR-34b-5p in the tissues. Pearson correlation analysis was used to evaluate the correlation between the expression of HCG18 and miR-34b-5p in osteosarcoma tissue. Osteosarcoma U2OS cells were cultured in vitro and transfected with si-HCG18, miR-34b-5p mimics, co-transfected with si-HCG18 and anti-miR-34b-5p or miR-34b-5p mimics and pcDNA-FOXP1. Then CCK-8 method and colony formation test were used to detect cell proliferation, scratch test and Transwell were used to detect cell migration and invasion, and Western blotting was used to detect the expression of FOXP1 protein in cells. The dual luciferase reporter gene experiment was applied to verify the regulatory relationship between HCG18 and miR-34b-5p, and between miR-34b-5p and FOXP1.

ResultsCompared with adjacent tissues, the expression of HCG18 in osteosarcoma tissue was increased (P < 0.01), and the expression of miR-34b-5p was decreased (P < 0.01). Pearson correlation analysis showed that the expression HCG18 and miR-34b-5p in osteosarcoma tissue was negatively correlated (r=-0.812, P < 0.05). After down-regulating HCG18 or up-regulating miR-34b-5p, the OD value of U2OS cells and number of clone formation decreased (P < 0.05), and scratch healing rate and number of invaded cells decreased (P < 0.05). HCG18 targeted and negatively regulated miR-34b-5p, while FOXP1 was the target gene of miR-34b-5p. Down-regulating miR-34b-5p reversed the inhibitory effect of down-regulating HCG18 on the proliferation, migration and invasion of osteosarcoma U2OS cells. Up-regulating FOXP1 reversed the inhibitory effect of up-regulating miR-34b-5p on the proliferation, migration and invasion of osteosarcoma U2OS cells.

ConclusionsThe expression of HCG18 is elevated in osteosarcoma tissues, which may promote the proliferation, migration and invasion of osteosarcoma cells by targeting the miR-34b-5p/FOXP1 axis.