Abstract:
Objective MiRNA is a kind of small non-coding RNAs that functions by regulating expression of the target gene after the genetic transcription. This study aims to analyze the differences of miRNAs expression between PC9 and PC9/GR cells, and to explore the relationship between miRNA and gefitinib resistance in non-small cell lung cancer (NSCLC).
Methods The gefitinib resistance on PC9/GR cells was evaluated using CCK8 assay. The total RNA of the two cell lines was isolated and examined. The miRNA expression of PC9/GR and PC9 was analyzed by microarray and the results were confirmed by real-time PCR method. Special miRNA was synthesized in vitro and was transfected into PC9/GR cells so as to observe the drug resistance of the model.
Results The values of IC50 of gefitinib on the PC9 and PC9/GR cells were 42.89 nmol/L, and 3.87μmol/L respectively (P < 0.01). The drug resistance index of PC9/GR cells related to the parental PC9 cells was 90.24. The microarray analysis showed that 55 human miRNAs were differentially expressed in the two cell lines (P < 0.01), of which 21 were up-regulated, including miR-1246 and miR-125b, and 34 were down-regulated, including miR-224 and miR-125a-5p. The expression of 9 miRNAs was further validated by real-time PCR, of which 8 were consistent with the microarray analysis, and one was not. MiR-125a-5p mimic was synthesized in vitro, and was transfected to PC9/GR. It promoted the effect of drug resistance.
Conclusion NSCLC resistantce to gefitinib is associated with a group of miRNAs. MiR-125a-5p can promote the effect of gefitinib resistance. This finding provides an experimental basis for further study of mechanism underlying the gefitinib resistance of NSCLC.