Abstract: Objective To investigate the expression and clinical significance of miRNA-148b （miR-148b） in lung adenocarcinoma （LAC） tissues and cell lines. Methods Realtime PCR was performed to detect the expression of miR-148b between 13 cases of LAC tissues and matched adjacent normal tissues. The expression of miR-148b was also detected in normal lung epithelial HBE cell line， and LAC cell lines H1437， H1975， A549 and PC14/B. The cell line with lowest expression was respectively transfected with miR-148b mimics and miR-148b control. Then，the effect of miR-148b on proliferation，colony formation and invasion ability were analyzed by MTT，low-density cell colony formation and transwell experiments. Results The average relative expression of miR-148b in LAC tissues and adjacent normal tissues were 0.61±0.42 and 0.91±0.32 （P＜0.05）. The expression levels of miR-148b in the H1437， H1975， A549， PC14/B cell lines were 0.42±0.08，0.38±0.02，0.29±0.03 and 0.21±0.04， lower than that in HBE cell line （the expression level was set as 1.00） with significance （P＜0.05）. PC14/B cell line was selected for the following experiments. MTT analysis showed that the absorbance value of miR-148b mimics group was much lower than that of miR-148b control group from the 3th day of the test （P＜0.05）. As for the low-density cell colony formation analysis，the relative colony formation number of PC14/B cells transfected with miR-148b mimics was 47±8，which was decreased significantly compared with miR-148b control group （set as 100） with significance （P＜0.05）. Transwell test showed that there was significant difference in the relative numbers of cells migrated through the basement membrane between miR-148b mimics group （82±22） and miR-148b control group （200±34） with significance （P＜0.05）.
Conclusion The expression of miR-148b is downregulated in both LAC tissue and cell lines. It can suppress the cell proliferation，colony formation and invasion ability of PC14/B cell in vitro.