Lipopolysaccharide confers to the acquired gefitinib resistance in human non-small cell lung cancer by activating nuclear-κB

The study was to confirm that lipopolysaccharide (LPS) could attenuate the gefitinib sensitivity of gefitinib resistance HCC827/GR-8-1 cell line and further to confirm that LPS regulate the gefitinib sensitivity by increasing the expression level of nuclear factor(NF)-κB.We successfully established the gefitinib resistance HCC827/GR-8-1 cell line.Then, cells were treated with LPS and/or gefitinib.To investigate the effect of LPS on non-small cell lung caner cell proliferation, we performed cell counting Kit-8 (CCK8) assay.Then, we conducted the colony formation assay and proliferation curve assay.The levels of caspase-3, bcl-2, and NF-κB were measured by Western blot analysis.Results show that we successfully established the EGFR-TKI-resistant lung cancer cells.Colony formation assay and proliferation curve assay indicated that LPS had little effect on the proliferation and colony formation of HCC827/GR-8-1 cells.But LPS could significantly up-regulate the resistance HCC827/GR-8-1 cells to gefitinib LPS markedly increased the expression level of NF-κB in HCC827/GR-8-1 cells.Additionally, the up-regulation of NF-κB correlated with cells' attenuated sensitivity to gefitinb. Key words: Non-small cell lung cancer; Lipopolysaccharide; Gefitinb resistance; Nuclear factor-κB