x43对人非小细胞肺癌 HCC827 细胞吉非替尼获得性耐药的影响

0bjective: To explore the efect of connexin 43 ( Cx43 ) on acquired gefitinib-resistance in human non small cell lung cancer （ NSCLC ）. Methods: A gefitinib-resistant (GR) NSCLC cell lines, HCC827 GR, from their parental cells were established. Gefitinib efficacy in HCC827 and HCC827 GR cells was detected by MTT assay. Expression of Cx43 mRNA in HCC827 and their GR cells was determined by RT-PCR. The protein expression of Cx43 and phospho-Akt (p-Akt) in these cells was detected by Western blot.The functional gap junction intercellular communication（GJIC）was measured by "parachute" assay.The cellular localization of Cx43 protein was evaluated by immunofluorescence staining. Result: MTT assay showed that less gefitinib cytotoxicity in established HCC827 GR cells than that in their parental cells with IC50 of 10.84 ± 0.021 μM versus 0.07 ± 0.019 μM, respectively. Moreover, both mRNA and protein expressions of Cx43 in HCC827 GR cells were significantly lower than that in HCC827 cells ( P＜0.05 ).However, the p-Akt protein in HCC827 GR cells is obviously higher than that in HCC827 cells ( P＜0.05 ).Furthermore,no detectable GJIC was found in HCC827 and their GR cells with or without RA (a well-defined GJIC enhancer) treatment. Immunofluorescence staining clearly showed that Cx43 protein accumulated in the cytoplasm of HCC827 and their GR cells. Conclusion: The down-regulation of Cx43 expression in cytoplasm of HCC827 GR cells may contribute to the acquired gefitinib resistance in NSCLC cells by GJIC-independent activation of PI3K/Akt signaling pathway.