RESUMO
OBJECTIVE: The aim of the study is to evaluate the effects of silencing a disintegrin and metalloproteinase 17 (ADAM17) gene expression by lentivirus-mediated RNA interference (RNAi) in the gefitinib-resistant lung adenocarcinoma cells, and then to explore whether the recombinant lentivirus mediated ADAM17 RNAi reversed the acquired resistance of lung adenocarcinoma to gefitinib in vitro. METHODS: The gefitinib-resistant RPC-9 cells were established and the mutations of EGFR were detected by gene sequencing. The ADAM17 shRNA expression vectors were constructed and packaged to recombinant lentivirus. The cell proliferation viability was detected by MTT, and cellular apotosis was analyzed by flow cytometry assay. The expression levels of ADAM17, EGFR and the phosphorylated EGFR were respectively detected by reverse transcription polymerase chain reaction and western blot. TGF-α production in the supernatant was detected by enzyme-linked immunosorbent assay. RESULTS: The gefitinib-resistant RPC-9 cells in which mutated EGFR (exon 20) carried 790T > T/M mutation were established. When the concentrations of gefitinib were less than 10µmol/L, there were no significant changes in the apoptosis and cellular proliferation of RPC-9 with the dose-escalation of gefitinib. The cell proliferation viability of RPC-9 was significantly decreased by lentivirus mediated ADAM17 RNAi (P < 0.05). Gefitinib did not inhibit ADAM17 expression in both the gefitinib-sensitive PC-9 and gefitinib-resistant RPC-9 cells (P > 0.05). Gefitinib had no significant effects on TGF alpha production in the supernatants (P > 0.05). Gefitinib did not inhibit EGFR expression in gefitinib-sensitive PC-9 and gefitinib-resistant RPC-9 cells (P > 0.05). The phosphorylation of EGFR in gefitinib-sensitive PC-9 cells was significantly inhibited by gefitinib (P < 0.05), but that in gefitinib-resistant RPC-9 could not be inhibited by gefitinib (P > 0.05). Lentivirus mediated ADAM17 RNAi significantly inhibited the mRNA and protein expression of ADAM17 in gefitinib-resistant RPC-9 cells (P < 0.05), as well as TGF alpha production in the supernatants (P < 0.05). Also, the phosphorylation of EGFR was significantly reduced in gefitinib-resistant RPC-9 cells by lentivirus mediated ADAM17 RNAi (P < 0.05); however, the mRNA and protein expression of EGFR could not be inhibited. CONCLUSION: Lentivirus mediated ADAM17 RNAi may reverse the acquired resistance of lung adenocarcinoma to gefitinib via inhibiting the upstream of EGFR signal pathway, which may provide a new therapeutic target to solve the acquired resistance to EGFR tyrosine kinase inhibitors in lung adenocarcinoma. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:196-205, 2018.