Abstract:

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)％ (P＜0.05). The proportions in S phase were (40.87±0.30) ％ and (31.74±0.40)％ (P＜0.05). 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(P＜0.05). 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.

Key words: Pemetrexed disodium; Lung neoplasms; A549 cells; EGFR gene; HER-3 gene