Different expressions of EGFR and HER-3 genes in human lung adenocarcinoma cells and pemetrexed-resistant cells

Objective To investigate different gene expressions of EGFR and HER-3 in human lung adenocarcinoma cells A549 and pemetrexed disodium(PEM)-resistant cells A549/PEM.Methods A549/PEM cell line was established with large dose of PEM.Growth inhibitions of A549 and A549/PEM cells were determined by CCK-8 assay.Cell cycle analysis was performed by flow cytometry(FCM).RT-PCR was used to analyse mRNA expressions of EGFR and HER-3 in A549 and A549/PEM cells.Results CCK-8 assay showed that the IC50 of PEM for A549 cells was 3.43×10-6mol/L.PEM-resistant cell line A549/PEM was established after being exposed to PEM repeatedly for 4 months,and the resistance index(RI) was 5.15.Flow cytometry analysis showed that proportions in G1/G0 phase of A549 and A549/PEM cells were(56.25±0.10)% and(65.12±0.40)%(P0.05).The proportions in S phase were(40.87±0.30) % and(31.74±0.40)%(P0.05).The mRNA expressions of EGFR in A549 and A549/PEM were 0.55±0.08 and 0.64±0.07,and mRNA expressions of HER-3 in A549 and A549/PEM were 1.29±0.03 and 1.56±0.12.The differences were statistically significant(P0.05).Conclusion Gene expressions of EGFR and HER-3 increase in A549/PEM cells,compared with that in A549 cells.It suggestes that changes of the two genes expressions appear to be associated with resistance to PEM.