PMID- 26923134 OWN - NLM STAT- MEDLINE DCOM- 20161213 LR - 20181113 IS - 1477-7819 (Electronic) IS - 1477-7819 (Linking) VI - 14 DP - 2016 Feb 29 TI - Overexpression of RBM5 induces autophagy in human lung adenocarcinoma cells. PG - 57 LID - 10.1186/s12957-016-0815-7 [doi] LID - 57 AB - BACKGROUND: Dysfunctions in autophagy and apoptosis are closely interacted and play an important role in cancer development. RNA binding motif 5 (RBM5) is a tumor suppressor gene, which inhibits tumor cells' growth and enhances chemosensitivity through inducing apoptosis in our previous studies. In this study, we investigated the relationship between RBM5 overexpression and autophagy in human lung adenocarcinoma cells. METHODS: Human lung adenocarcinoma cancer (A549) cells were cultured in vitro and were transiently transfected with a RBM5 expressing plasmid (GV287-RBM5) or plasmid with scrambled control sequence. RBM5 expression was determined by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blot. Intracellular LC-3 I/II, Beclin-1, lysosome associated membrane protein-1 (LAMP1), Bcl-2, and NF-kappaB/p65 protein levels were detected by Western blot. Chemical staining with monodansylcadaverine (MDC) and acridine orange (AO) was applied to detect acidic vesicular organelles (AVOs). The ultrastructure changes were observed under transmission electron microscope (TEM). Then, transplanted tumor models of A549 cells on BALB/c nude mice were established and treated with the recombinant plasmids carried by attenuated Salmonella to induce RBM5 overexpression in tumor tissues. RBM5, LC-3, LAMP1, and Beclin1 expression was determined by immunohistochemistry staining in plasmids-treated A549 xenografts. RESULTS: Our study demonstrated that overexpression of RBM5 caused an increase in the autophagy-related proteins including LC3-I, LC3-II, LC3-II/LC3-I ratio, Beclin1, and LAMP1 in A549 cells. A large number of autophagosomes with double-membrane structure and AVOs were detected in the cytoplasm of A549 cells transfected with GV287-RBM5 at 24 h. We observed that the protein level of NF-kappaB/P65 was increased and the protein level of Bcl-2 decreased by RBM5 overexpression. Furthermore, treatment with an autophagy inhibitor, 3-MA, enhanced RBM5-induced cell death and chemosensitivity in A549 cells. Furthermore, we successfully established the lung adenocarcinoma animal model using A549 cells. Overexpression of RBM5 enhanced the LC-3, LAMP1, and Beclin1 expression in the A549 xenografts. CONCLUSIONS: Our findings showed for the first time that RBM5 overexpression induced autophagy in human lung adenocarcinoma cells, which might be driven by upregulation of Beclin1, NF-kappaB/P65, and downregulation of Bcl-2. RBM5-enhanced autophagy acts in a cytoprotective way and inhibition of autophagy may improve the anti-tumor efficacy of RBM5 in lung cancer. FAU - Su, Zhenzhong AU - Su Z AD - Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin, 130041, People's Republic of China. su_zhenzhong@163.com. FAU - Wang, Ke AU - Wang K AD - Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin, 130041, People's Republic of China. kewangm1@hotmail.com. FAU - Li, Ranwei AU - Li R AD - Department of Urinary Surgery, The Second Affiliated Hospital of Jilin University, Changchun, Jilin, 130041, People's Republic of China. ranwei1968@yahoo.com. FAU - Yin, Jinzhi AU - Yin J AD - Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin, 130041, People's Republic of China. yjz6437@163.com. FAU - Hao, Yuqiu AU - Hao Y AD - Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin, 130041, People's Republic of China. hao.yu.qi.u@163.com. FAU - Lv, Xuejiao AU - Lv X AD - Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin, 130041, People's Republic of China. lvxuejiao0311@163.com. FAU - Li, Junyao AU - Li J AD - Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin, 130041, People's Republic of China. 13943175477@126.com. FAU - Zhao, Lijing AU - Zhao L AD - Department of Pathophysiology, Norman Bethune College of Medicine of Jilin University, Changchun, Jilin, 130021, People's Republic of China. zhao_lj@jlu.edu.cn. FAU - Du, Yanwei AU - Du Y AD - Department of Pathophysiology, Norman Bethune College of Medicine of Jilin University, Changchun, Jilin, 130021, People's Republic of China. 1079389886@qq.com. FAU - Li, Ping AU - Li P AD - Department of Paediatrics, The Second Affiliated Hospital of Jilin University, Chuangchun, Jilin, 130041, People's Republic of China. lypinglp@163.com. FAU - Zhang, Jie AU - Zhang J AD - Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin, 130041, People's Republic of China. 18643111766@163.com. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20160229 PL - England TA - World J Surg Oncol JT - World journal of surgical oncology JID - 101170544 RN - 0 (Cell Cycle Proteins) RN - 0 (DNA-Binding Proteins) RN - 0 (RBM5 protein, human) RN - 0 (RNA, Messenger) RN - 0 (RNA-Binding Proteins) RN - 0 (Tumor Suppressor Proteins) SB - IM MH - Adenocarcinoma/genetics/metabolism/*pathology MH - Animals MH - Apoptosis/*drug effects MH - Autophagy/*drug effects MH - Blotting, Western MH - Cell Cycle Proteins/genetics/*metabolism MH - DNA-Binding Proteins/genetics/*metabolism MH - Female MH - Humans MH - Immunoenzyme Techniques MH - Lung Neoplasms/genetics/metabolism/*pathology MH - Mice MH - Mice, Inbred BALB C MH - Mice, Nude MH - RNA, Messenger/genetics MH - RNA-Binding Proteins/genetics/*metabolism MH - Real-Time Polymerase Chain Reaction MH - Reverse Transcriptase Polymerase Chain Reaction MH - Tumor Cells, Cultured MH - Tumor Suppressor Proteins/genetics/*metabolism MH - Xenograft Model Antitumor Assays PMC - PMC4770605 EDAT- 2016/03/01 06:00 MHDA- 2016/12/15 06:00 PMCR- 2016/02/29 CRDT- 2016/03/01 06:00 PHST- 2015/10/29 00:00 [received] PHST- 2016/02/17 00:00 [accepted] PHST- 2016/03/01 06:00 [entrez] PHST- 2016/03/01 06:00 [pubmed] PHST- 2016/12/15 06:00 [medline] PHST- 2016/02/29 00:00 [pmc-release] AID - 10.1186/s12957-016-0815-7 [pii] AID - 815 [pii] AID - 10.1186/s12957-016-0815-7 [doi] PST - epublish SO - World J Surg Oncol. 2016 Feb 29;14:57. doi: 10.1186/s12957-016-0815-7.