4241 - LncRNA-GC1 contributes to gastric cancer chemo-resistance through inhibition of miR-551b-3p and the overexpression of dysbindin

Background

Chemo-resistance is one of the important causes of poor prognosis of gastric cancer patients, but the exact mechanism is still not very clear. The regulation of lncRNA and miRNA and its downstream target genes has become in focus of the field.

Methods

In this study, we performed lncRNA and miRNA microarray analysis of chemo-resistant cells (SGC7901/Oxaliplatin). Then, bioinformatics analysis, TaqMan real-time PCR, western blot, luciferase reporter gene assay, RNA co-immunoprecipitation, cell proliferation and apoptosis analysis were used to explicit the lncRNA-miRNA-mRNA pathway in gastric cancer chemo-resistance. Last, nude mice were used to verify the promotion of chemo-resistance in vivo.

Results

In this study, we identified a lncRNA-GC1, which was upregulated in chemo-resistant gastric cancer tissues and cells, and a miRNA-551b-3p, which was downregulated in chemo-resistant gastric cancer tissues and cells. Firstly, miR-551b-3p can directly bind to the non-coding region of dysbindin mRNA, thereby negatively regulating the expression of dysbindin which was involved in chemotherapy resistance in gastric cancer cells. Secondly, lncRNA-GC1 promotes chemoresistance in gastric cancer by competitively binding to miR-551b-3p to facilitate dysbindin expression in vitro and in vivo. Thirdly, the expression levels of lncRNA-GC1 were positively correlated with tumor size (P = 0.002), lymph node invasion (P = 0.001) and poor platinum response (P < 0.001). Kaplan-Meier curves show that patients with high lncRNA-GC1 expression exhibit poorer overall survival compared with those with low lncRNA-GC1 expression. Multivariate analysis indicated that lncRNA-GC1 serves as an independent prognostic factor for patients with gastric cancer (P = 0.001).

Conclusions

LncRNA-GC1-miRNA-551b-3p-dysbindin signaling pathway may serve as a predictor for oxaliplatin response and a potential therapeutic target for gastric cancer.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Guo Xin.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.