Fig. 5

Detection of cirRNA CCDC66 expression in LADC cells. a Expression of cirRNA CCDC66 was detected by RT-PCR in LADC cells. b Its expression correlated with levels of FAK mRNA, a vital marker closely associated with cancer metastasis and EMT. c Silencing of FAK expression reduced d cirRNA CCDC66. e Addition of HGF (50 ng/ml) increased expression of cirRNA CCDC66. f Silencing of nicotinic acetylcholine receptor alpha 7 (nAchRα7), in contrast, increased levels of CCDC66β and g cirRNA CCDC66. h Comparing gene expression patterns of pEGFR, c-MET, and FAK in EGFR-mutated H1975 and wild-type A549 cells. i Expression of pEGFR, c-MET, and FAK was higher in EGFR-mutated H1975 cells. Level of nAchRα7, in contrast, was higher in A549 cells. i Expression of cirRNA CCDC66 was also higher in H1975 cells. j Addition of FAK inhibitor Y15 (1,2,4,5-benzenetetramine tetrahydrochloride) inhibited expression of FAK, nAchR7α, and CCDC66α. Y15 inhibited expression of nAchR7α at a concentration of 7.5 μM, CCDC66α at a concentration of 10 μM, and FAK at a concentration of 15 μM. k Y15, however, increased cirRNA CCDC66 expression. l Addition of nicotine also increased cirRNA CCDC66 expression