Differential expression of serum miRNAs in patients with advanced non-small cell lung cancer treated by gifitinib before and after acquiring drug resistance / 中南大学学报(医学版)

ABSTRACT

To explore the differential expression of serum miRNAs in patients of advanced non- small cell lung cancer (NSCLC) treated by gifitinib before and after acquiring drug resistance.
 Methods: A total of 4 patients with advanced NSCLC from Affiliated Hospital of Yueyang Vocational Technical College, who acquired drug resistance during gefitinib therapy from June 2013 to June 2015, were enrolled. Serum samples were collected before treatment and after acquiring drug resistance. MicroRNA (miRNA) microarray was used to assess the levels and compositions of miRNAs in serum. Real-time RT-PCR was used to validate the results of miRNAs with significant differences in expression. The candidate miRNAs inhibitors and mimics were transfected into lung cancer cells by liposome, and the sensitivity of lung cancer cells to gifitinib was detected.
 Results: The miRNA microarray showed that there were significantly differential expression of miRNAs in serum of NSCLC patients after acquiring drug resistance, and 24 miRNAs were changed in more than 2-fold. Among them, 19 miRNAs were up-regulated and 5 miRNAs were down- regulated (both P<0.05). Especially, the expression of miR-21 in serum of NSCLC patients after obtaining resistance was up-regulated more than 10-fold compared with that before treatment. The results of RT-PCR was consistent with the results of miRNA microarray. The up-regulation of miR-21 in lung cancer cells could elevate the half maximal inhibition concentration (IC50) of gefitinib, and the down-regulation of miR-21 in lung cancer cells could reduce the IC50 of gefitinib (both P<0.05).
 Conclusion: There is differential expression of miRNAs in serum of NSCLC patients before treatment and after acquiring drug resistance during gefitinib therapy. The up-regulation of miR-21 may be involved in regulating the acquiring drug resistance of gefitinib.