| Objective:Lung cancer is one of the most common cancers worldwide,accounting for the highest incidence and mortality.LKB1 suppresses tumor through 14 downstream protein kinases,and AMPK plays a key role.Previous studies indicated that PDK4 is critical for Warburg effect.Thereofore,we aim to uncover the mechanisms of the expression of PDK4 induced by LKB1;investigate effects of AMPK and other downstream kinases.Our study will further elucidate the pathogenesis of lung cancer.Methods:We screen differential genes in A549 and a549-LKB1 by Bioinformatics.Lung cancer and adjacent normal tissue were collected and analyzed by Multiple fluorescence immunohistochemical staining technique to detect the expression of LKB1 and PDK4 and their correlation.We performed q PCR or WB to detect PDK4 expression in A549/A549 LKB1/H460/H460 LKB1 cell line.The decreased capacity of cell proliferation were measured using CCK8 after PDK4 was knocked out by si RNA.We investigated the role of AMPK and SIKs on PDK4 using gene editing technology and chemical agonist or inhibitor.Results:1.Analyze the microarray sequencing results of A549-NC,A549-NC+Met,A549-LKB1,A549-LKB1+Met,and screen out the differential gene PDK4,which is highly expressed in LKB1 deficient cells.2.Overexpression of LKB1 significantly down-regulated PDK4 in A549 and H460 cell lines(p<0.05),and this effect cannot be restored by silencing AMPK.3.The expression of PDK4 in lung cancer was distinctly higher than normal tissue.LKB1 and PDK4 is negatively-corelated(P<0.01).4.Cell proliferation ability was impaired after PDK4 knock-down(p<0.05).5.After treatment of AMPK activator AICAR and metformin in A549 and H460,the expression of PDK4 increased(P<0.05).6.We used SIK inhibitor HG-9-91-01 to treat lung cancer and found PDK4 was up-regulated.Conclusion:In lung cancer,LKB1 inhibits the expression of PDK4 via SIKs.On the country,AMPK activation up-regulates PDK4 expression. |
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