Abstract: Objective: To explore the effect of miR-370-3p on the proliferation, migration, and invasion of oral squamous cell carcinoma SCC-9 cells, and analyze its possible mechanism of action.Methods: The expression of miR-370-3p and NPC1 in normal human oral keratinocytes (NOK) and SCC-9 cells was compared.SCC-9 cells were divided into miR-370-3p mimic group, miR-370-3p negative control (NC) group, miR-370-3p inhibitor group and miR-370-3p inhibitor-NC group.Clonal formation assay was used to detect cell colony forming ability.Cell counting kit-8 (CCK-8) assay, scratch assay and Transwell assay were used to detect cell proliferation, migration and invasion ability, respectively.Real-time fluorescence quantitative PCR (RT-qPCR) assay was used to detect miR-370-3p expression.Dual luciferase assay was used to detect the targeting of miR-370-3p to NPC1, and western blotting was used to detect the expression of NPC1 protein.Results: Compared with NOK cells, the expression of miR-370-3p was up-regulated and the expression of NPC1 was down-regulated in SCC-9 cells (all P< 0.05).Compared with the mimic NC group, the expression level of miR-370-3p was increased and the expression level of NPC1 protein was decreased in the miR-370-3p mimic group.Cell viability was enhanced, scratch mobility was decreased, and the number of transmembrane cells was increased(all P< 0.05).The change trend of the above indexes of the miR-370-3p inhibitor group was opposite to that of the miR-370-3p mimic group (all P< 0.05).Luciferase assay results showed that miR-370-3p could target the 3'-UTR binding to NPC1 and inhibit the expression of NPC1 protein (P< 0.05).Conclusion: The miR-370-3p can promote the proliferation, migration and invasion of SCC-9 cells, and its mechanism may be related to the regulation of the expression of its downstream target gene NPC1.