RESUMO
Objective: To investigate the expression of intraflagellar transport 20 (IFT20) protein in lung cancer tissues and its effect on the proliferation of lung cancer A549 cells. Methods: The expressions of IFT20 protein in 20 specimens of lung cancer tissues and 4 specimens of normal lung tissues were detected by immunohistochemistry. After the small interfering RNA (siRNA) targeting IFT20 gene was transfected into A549 cells, the expression level of IFT20 mRNA was detected by real-time fluorescence-based quantitative-PCR, the proliferation of A549 cells was determined by MTT assay, the number and length of cilia were observed by immunofluorescence staining, and the proteins expressions in A549 cells were measured by protein chip detection. Results: The expression of IFT20 protein was weakly positive in lung cancer tissues and moderately positive in normal lung tissues. The expression level of IFT20 mRNA in lung cancer A549 cells after transfection with IFT20-targeted siRNA was lower than those in the negative control cells (A549 cells were transfected with control siRNA) and the blank control cells (A549 cells with no transfection) (P < 0.05). The proliferation of A549 cells after transfection with IFT20-targeted siRNA was accelerated (P < 0.05), the expression level of IFT20 protein was down-regulated, the number of cilia was reduced, the length of cilia was shorterned, or the cilia was disappeared (all P < 0.05). The expression levels of X-linked inhibitor of apoptosis protein (XIAP), survivin, high temperature requirment A (HTRA), heat shock protein (Hsp) 27, Hsp70 and second mitochondria-derived activator of caspase (SMAC) were up-regulated (all P < 0.05). Conclusion: The IFT20 protein is lowly expressed in lung cancer tissues. After the inhibition of IFT20 expression, the cilia become less and shorter, which promotes the proliferation of lung cancer A549 cells.