Knockdown of long non-coding RNA LCPAT1 inhibits autophagy in lung cancer

Objective: Long non-coding RNAs(lnc RNAs) are involved in numerous biological processes in lung cancer cells. In our previous studies, we identified a lnc RNA, ENST00000439577, which is highly expressed in lung carcinomas, and termed it lung cancer progression-associated transcript 1(LCPAT1). To characterize the role of LCPAT1 in lung cancer, we conducted the current study.Methods: Expression of LCPAT1 and autophagy-associated markers in tumor tissues and lung cancer cell lines was determined by real-time quantitative polymerase chain reaction(q PCR). Hematoxylin and eosin(HE) staining, q PCR, Western blot, and immunohistochemistry were performed to evaluate xenografted tumor tissues. Autophagy induced by rapamycin was detected by Western blot and immunofluorescence in lung cancer cell lines.Results: Expression of LCPAT1 and microtubule-associated protein 1 light chain 3 beta(LC3B) was positively correlated in lung cancer. Knockdown of LCPAT1 inhibited tumor growth and suppressed cell autophagy in vivo. Moreover, LCPAT1 knockdown in lung cancer cell lines resulted in decreased autophagy-associated gene expression and alleviated the cell autophagy induced by rapamycin.Conclusions: We speculate that LCPAT1 plays a crucial role in regulating autophagy in lung cancer.

Promoter methylation of Wnt/β-Catenin signal inhibitor TMEM88 is associated with unfavorable prognosis of nonsmall cell lung cancer

Objective:Recent research has indicated that altered promoter methylation of oncogenes and tumor suppressor genes is an important mechanism in lung cancer development and progression.In this study,we investigated the association between promoter methylation of TMEM88,a possible inhibitor of the Wnt/β-Catenin signaling,and the survival of patients with nonsmall cell lung cancer(NSCLC).Methods:Twelve pairs of tumor and adjacent non-tumor samples were used for microarray analyses of DNA methylation and gene expression.For validation,more than two hundred additional samples were analyzed for methylation using bisulfite pyrosequencing and for gene expression using q RT-PCR.Then the cell function were tested by wound healing,transwell,CCK8 and cell cycle assay.Results:Our analysis of patient specimens showed that TMEM88 methylation was higher in NSCLC tumors(82.2%±10.3,P<0.01)compared with the adjacent normal tissues(65.9%±7.2).The survival analysis revealed that patients with high TMEM88methylation had a shorter overall survival(46 months)compared with patients with low TMEM88 methylation(>56 months;P=0.021).In addition,we found that demethylation treatment could inhibit tumor cell proliferation,migration,and invasion,which was supportive of an association between methylation and survival.Conclusions:Based on these consistent observations,we concluded that TMEM88 may play an important role in NSCLC progression and that promoter methylation of TMEM88 may serve as a biomarker for NSCLC prognosis and treatment.