[Effects of heme oxygenase-1 knockdown on proliferation, invasion and metastasis of lung adenocarcinoma A549 cells and its mechanism].

Objective: To investigate the effects of heme oxygenase-1 (HO-1) knockdown on proliferation, invasion and migration of lung adenocarcinoma A549 cells and explore the mechanism. Methods: The expression levels of HO-1 mRNA in human bronchial epithelial cells (HBECs) and human lung cancer cell lines (A549, H1299, H358 and H1993) were detected by real-time quantitative polymerase chain reaction (RT-qPCR), and immunohistochemistry (IHC) was used to detect the expression level of HO-1 in human lung adenocarcinoma specimens. The HO-1 short hairpin RNA (shRNA) was transfected into A549 cells by RNA interference technique. HO-1 stably deleted A549 cells were selected (HO-1 shRNA group) and verified by RT-qPCR and western blot. HO-1 shRNA A549 cells and control shRNA A549 cells were treated with the inducer of autophagy Torin1 or its inhibitor Bafilomycin A1 (Baf A1), respectively. The expressions of autophagic markers LC3B and p62 were determined by western blot. The proliferation, invasion and migration abilities of each group of A549 cells were assessed by cell counting, Transwell and wound healing assays, respectively. Results: The expressions of HO-1 mRNA in lung cancer cell lines (A549, H1299, H358 and H1993) were significantly higher than that of HBECs, and HO-1 upregulated in human lung adenocarcinoma. The expression of p62 protein and the ratio of LC3B-Ⅱ/ LC3B-Ⅰ in no treatment group, Torin1 treatment group and Baf A1 treatment group were significantly higher than those of the corresponding control group (P<0.05). After 11 days of culture, the number of cells in HO-1 shRNA group were 41.8%, 30.4% and 14.0% of the corresponding control group, respectively. The number of lower chamber cells in HO-1 shRNA group were (35.7±2.1), (27.0±1.0) and (38.0±1.0)/field, respectively, which were lower than (66.0±9.2), (39.3±1.2) and (43.0±2.6)/field of the corresponding control group, respectively (P<0.05). The migration distances of HO-1 shRNA group were (7.47±0.91) mm, (4.23±0.82) mm and (5.42±0.24) mm, which were lower than (10.07±1.26) mm, (7.14±0.07) mm and (12.04±0.80) mm of the corresponding control groups, respectively (P<0.05). Conclusion: Knockdown of HO-1 inhibits the proliferation, invasion and migration of A549 cells by impeding autophagy.