Effect of long non-coding RNA EIF3J-AS1 on multi-drug resistance and autophagy in gastric cancer.

Abstract

e15581 Background: Gastric cancer (GC) is a leading cause of cancer mortality worldwide, oxaliplatin and epirubicin based chemotherapy are one of the most important treatment options for GC patients. However, drug resistance, especially multi-drug resistance remains a major obstacle for successful chemotherapy. Recently, long non-coding RNAs (lncRNAs) have been widely identified to play emerging roles in diverse physiological and pathophysiological processes including drug resistance. Our previous bioinformatics analysis showed long non-coding RNA EIF3J-AS1 was a potential multi-drug resistance gene, but the underlying mechanism is still unknown. Methods: We generated oxaliplatin resistance cells (MGC803/OXA) and epirubicin resistance cells(MGC803/EPI) based on parental gastric cancer cells MGC803. Relative expression levels of EIF3J-AS1 were measured by qRT-PCR. Transmission electron microscopy was used to measure autophagosomes. Rapamycin was applied to inducing autophagy while chloroquine and 3-methyladenine were used to block autophagy. Protein level of autophagy related genes were examined by Western Blot. Coexpression genes of EIF3J-AS1 from TCGA RNA-seq datas were analyzed by cBiportal. RNA immunoprecipitation was used to analyze endogenous microRNAs and mRNAs. Results: EIF3J-AS1 was significantly upregulated in MGC803/OXA and MGC803/EPI cells compared with parental cells MGC803. EIF3J-AS1 inhibition increased chemosensitivity to both oxaliplatin and epirubicin. Moreover, EIF3J-AS1 silence lead to the decrease of autophagy. Autophagy related gene ATG14 was identified as a downstream target gene. EIF3J-AS1 promoted ATG14 expression by directly interacting with and increasing stability of ATG14 mRNA, On the other hand, EIF3J-AS1 competitively sponged miR-188-3p and promoted ATG14 expression in a ceRNA-dependent way. Conclusions: LncRNA EIF3J-AS1 is a crucial regulator of multi-drug resistance by inducing autophagy in gastric cancer. Targeting EIF3J-AS1/ATG14 axis might be a new paradigm for cancer therapeutics.