Preliminary Study On The Role Of MiR-146a-5p In Chemotherapy Resistance Of Small Cell Lung Cancer

BackgroundLung cancer is one of the most important causes of death in the world.In the past decade,its incidence and fatality rate have been ranking the top among all cancers,among which,small cell lung cancer(SCLC)accounts for about 10-15% of the total lung cancer.At present,the main treatment of SCLC is platinum combined with etoposide chemotherapy as its first-line treatment,but it is very easy to form multidrug resistance(MDR),so that its treatment effect is not good,and the 5-year survival rate is less than 10%.SCLC resistance mechanism is very complex,but at present domestic and foreign scholars research on molecular mechanism of SCLC multi-resistant is not yet clear,at the same time,the lack of effective clinical SCLC biological markers of drug resistance,therefore,clinical drug resistance is an urgent need to find reliable predictor of SCLC biological markers,elucidate the molecular mechanism of SCLC resistance,resistance to overcome SCLC provide new treatments.ObjectiveTo preliminarily investigate the role of miR-146a-5p in the mechanism of chemotherapy resistance in small cell lung cancer.MethodThe expression levels of miR-146a-5p in drug-resistant cell lines(H69-AR)and sensitive cell lines(H69)of SCLC were tested by real-time quantitative PCR(qRT-PCR)to explore the correlation between miR-146a-5p and drug resistance of SCLC.The expression of miR-146a-5p was up-regulated or inhibited by stably transfected with lentiviral vector miR-146a-5p mimic or miR-146a-5p inhibitor,respectively.The biological effects of miR-146a-5p expression level on SCLC cell lines were verified by CCK-8 method and scratch experiments.The relevant literature was consulted and the current authoritative biological software was applied to predict the target genes of miR-146a-5p,and the relationship between miR-146a-5p and the predicted target genes was detected by Western blot and qRT-PCR.ResultThe expression level of miR-146a-5p in H69-AR compared with H69 cell line was(1:22.70)(P<0.05).The potential target genes of miR-146a-5p were predicted by biological software to be IL-1receptor-associated kinase 1(IRAK1)and TNF receptorassociated factor 6(TRAF6).The expression levels of mIRAK1 and mTRAF6 in H69-AR relative to H69 cells were significantly different(4.92:1.00)and(2.76:1.00)(P<0.05).After transfection of miR-146a-5p mimic in H69 AR cell line,compared with the control group,the cell inhibition rate increased,the migration rate slowed down,and the expression levels of mIRAK1 and mTRAF6 decreased to(1.00: 14.55)and(1: 3.20),respectively.The expressions of IRAK1 and TRAF6 were decreased to(1.00: 0.24)and(1.00:0.31)(P<0.05).After transfection of miR-146a-5p inhibitor in H69 cell line,compared with the control group,the cell inhibition rate decreased and the migration rate increased.At the same time,the expression levels of mIRAK1 and mTRAF6 increased to(10.86:1.00)and(4.64:1.00),respectively.The expressions of IRAK1 and TRAF6 increased to(4.76:1.00)and(3.96:1.00,respectively).(P < 0.05).ConclusionMiR-146a-5p inhibits chemotherapy resistance in small cell lung cancer by targeting IRAK1 and TRAF6 genes.