miR-455-3p serves as prognostic factor and regulates the proliferation and migration of non-small cell lung cancer through targeting HOXB5.

MicroRNAs (miRs) have been reported to play significantly roles in the initiation and progression of human cancers. miR-455-3p has been recently found could function as tumor suppressor in various human cancers. However, its expression and biological role in non-small cell lung cancer (NSCLC) remains elusive. In this study, we found miR-455-3p was markedly downregulated in NSCLC tissues and cell lines. Chi-square test to analyze the correlations between miR-455-3p expression and clinicopathological features revealed that miR-455-3p expression was correlated with poorly differentiated cancer and advanced tumor stage (P < 0.05). Kaplan-Meier curve revealed that low expression of miR-455-3p was correlated with shorter 5-year survival time (P = 0.029). Univariate and multivariate analyses identified low miR-455-3p expression was an unfavorable prognostic factor for overall survival. Gain-of-function and loss-of-function studies revealed that miR-455-3p inhibits cell proliferation and migration in vitro. Computer algorithm and dual-luciferase reporter assay revealed that miR-455-3p directly targets and suppresses HOXB5 in NSCLC. Further studies demonstrated that knockdown of HOXB5 attenuated the effect of miR-455-3p downregulation on cell proliferation and migration. Taken together, our results for the first time suggested that miR-455-3p was downregulated in NSCLC and was correlated with the poor prognosis of NSCLC patients. Also, miR-455-3p functions as tumor suppressor by directly targeting HOXB5 in NSCLC progression and may be used as a potential target for NSCLC treatment.