Maimendong and Qianjinweijing Tang combined with cisplatin suppressed lung cancer through targeting lncRNA-p21.

ETHNOPHARMACOLOGICAL RELEVANCE: Maimendong and Qianjinweijing Tang (Jin formula) is a traditional Chinese medicine formula that has been proven effective in the treatment of lung cancer in long-term clinical practice. AIM OF THE STUDY: To evaluate the anti-tumor effects of Jin formula combined with cisplatin (JIN + DDP) in vivo and in vitro, as well as to explore the role of long non-coding RNA (lncRNA) in the anti-lung cancer mechanism of its action. MATERIALS AND METHODS: A Lewis lung cancer model was established in C57 BL/6 mice to study the in vivo anti-tumor effect of Jin formula combined with cisplatin. TUNEL staining and western blot were applied to study the effects of Jin formula combined cisplatin on apoptosis. The in vitro anti-cancer function of Jin formula combined with cisplatin was explored by cell viability assay, flow cytometry, wound healing assay and transwell assay. The changes in lncRNA expression profiles were determined by lncRNA microarray, and the differentially expressed lncRNA-p21 was verified by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis. The expression differences of lncRNA-p21 in tumor and normal tissues were analyzed by bioinformatics, and the expression differences of lncRNA-p21 in tumor cells and normal cells were detected by qRT-PCR. The role of lncRNA-p21 in the anti-cancer effect of Jin formula combined cisplatin was investigated by knockdown or overexpression of lncRNA-p21 and a series of cell experiments. The expression of MAPK pathway-related proteins was analyzed by western blot. RESULTS: Jin formula combined with cisplatin (JIN + DDP) can suppress tumor growth and promote apoptosis in Lewis lung cancer mouse model. LncRNA-p21 was significantly up-regulated in the JIN and JIN + DDP groups, and the expression of lncRNA-p21 in lung cancer tissues and cells was lower than that in normal tissues and cells. In vitro, JIN + DDP significantly induced apoptosis and inhibited the proliferation, migration, and invasion of H460 and H1650 lung cancer cells. The above effects can be enhanced by the overexpression of lncRNA-p21 and eliminated by knock-down of lncRNA-p21. Further studies revealed that JIN + DDP inhibited the expression of mitogen-activated protein kinase (MAPK) pathway-related proteins, whereas knock-down of lncRNA-p21 abrogated the inhibition of the MAPK signaling pathway. CONCLUSIONS: This study showed that Jin formula combined with cisplatin could effectively inhibit the progression of lung cancer partially through targeting lncRNA-p21.

Arsenic represses airway epithelial mucin expression by affecting retinoic acid signaling pathway.

Arsenic is a ubiquitous environmental toxicant, found in high concentrations worldwide. Although abundant research has dealt with arsenic-induced cancers, studies on mechanisms of non-malignant lung diseases have not been complete. In addition, decades of research have mostly concentrated on high-dose arsenic exposure, which has very limited use in modeling the biological effects of today's low-dose exposures. Indeed, accumulated evidence has shown that low-dose arsenic exposure (i.e. ≤100 ppb) may also alter lung homeostasis by causing host susceptibility to viral infection. However, the underlying mechanism of this alteration is unknown. In this study, we found that low-dose sodium arsenite (As (III)) repressed major airway mucins-MUC5AC and MUC5B at both mRNA and protein levels. We further demonstrated that this repression was not caused by cellular toxicity or mediated by the reduction of a common mucin-inducing pathway-EGFR. Other established mucin activators- dsRNA, IL1ß or IL17 were not able to override As (III)-induced mucin repression. Interestingly, the suppressing effect of As (III) appeared to be partially reversible, and supplementation of all trans retinoic acid (t-RA) doses dependently restored mucin gene expression. Further analyses indicated that As (III) treatment significantly reduced the protein level of retinoic acid receptors (RARα, γ and RXRα) as well as RARE promoter reporter activity. Therefore, our study fills in an important knowledge gap in the field of low-dose arsenic exposure. The interference of RA signaling, and mucin gene expression may be important pathogenic factors in low-dose arsenic induced lung toxicity.