Abstract:

Objective To investigate the regulation and mechanism of miR-155-5p on the proliferation，migration and invasion of oral squamous cell carcinoma（OSCC） cells. Methods Human OSCC cell lines CAL-27，HN4，HN6，SCC4，TCA8113 and normal oral epithelial keratinocyte line HOK were collected to determine the expression of miR-155-5p. According to the different transfection plasmids，they were classified into miR-NC group（transfected negative control with miR-155-5p mimics），miR-155-5p group（transfected with miR-155-5p mimics） and anti-NC group（transfected negative control with miR-155-5p inhibitor），anti-miR-155-5p group（transfected with miR-155-5p inhibitor），Vector group（transfected with empty plasmid vector），pc-ARID2 group（transfected with ARID2 overexpression plasmid），miR-NC+Vector group（co-transfected with negative control and empty plasmid vector），miR-155-5p+Vector group（co-transfected with miR-155-5p mimics and empty plasmid vector） and miR-155-5p+pc-ARID2 group（co-transfected with miR-155-5p mimics and ARID2 overexpression plasmid）. The cell proliferation was determined by CCK-8 assay and clonal formation assay，the migration and invasion of CAL-27 cells and HN4 cells were determined by scratch assay and invasion assay，and the expression of ARID2 protein was determined by western blot. Dual luciferase reporter gene assay was used to verify the targeting relationship between miR-155-5p and ARID2. Results Compared with oral epithelial keratinocyte line HOK，OSCC cell lines（SCC4，HN6，HN4，CAL-27，TCA8113） showed significantly up-regulated miR-155-5p expression（P<0.01）. Compared with anti-NC group，the relative expression of anti-miR-155-5p inhibitor group was significantly decreased（P<0.01）. The proliferation activity，clonal formation number，scratch closure rate and invasion cell number were decreased（P<0.01）. Compared with miR-NC group，the expression of ARID2 in miR-155-5p group was down-regulated（P<0.01），and the proliferation activity，clonal formation number，scratch closure rate and invasion cell number were increased（P<0.01）. The expression of ARID2 in anti-miR-155-5p inhibitor group was up-regulated（P<0.01），and the proliferation activity，clonal formation number，scratch closure rate and invasion cell number were decreased（P<0.01）. Compared with co-transfected miR-NC and pmiR-ARID2 wild-type plasmid（pmiR-ARID2-wt），the luciferase activity was decreased after co-transfecting miR-155-5p mimic and pmiR-ARID2 mutant-type plasmid（pmiR-ARID2-wt）（P<0.01）. Compared with Vector group，the expression of ARID2 mRNA in pc-ARID2 group was up-regulated（P<0.01），and the proliferation activity，clonal formation number，scratch closure rate and invasion cell number were decreased（P<0.01）. Compared with miR-NC+Vector group，the proliferation activity，clonal formation number，scratch closure rate and invasion cell number in miR-155-5p+Vector group were increased（P<0.01）. Compared with miR-155-5p+Vector group，the proliferation activity，clonal formation number，scratch closure rate and invasion cell number in miR-155-5p+pc-ARID2 group were decreased（P<0.01）. Conclusions The expression of miR-155-5p is up-regulated in OSCC cells，and it can promote the proliferation，migration and invasion of OSCC cells through targeted inhibition of ARID2 expression，thus playing the role of oncogene.

Key words: MicroRNA-155-5p, AT-rich interaction domain 2, Oral squamous cell carcinoma, Proliferation, Migration, Invasion