The Study On Reverse Effect Of Drug-resistance Of A549/DDP Cells By RNA Interference Targeting HIF-1 Alpha Gene

Objective: HIF-1αis a transcript factor which is widely exists in vivo when lacking of oxygen,its high expression often increases tumor cells' multidrug resistance.The study transfected A549/DDP with HIF-1a siRNA, observed its influention of the drug-resistance of cisplatin.Methods: Transfected A549/DDP cells with HIF-1αsiRNA which had been constructed all the cells were randomized to four groups :A549/DDP group,low oxygen A549/DDP group,low oxygen A549/DDP+siRNA negative group,low oxygen A549/DDP+siRNA positive group.The change of the expression of HIF-1αmRNA,MDR1mRNA,MRPmRNA were examined by RT-PCR in different groups. The change of the expression of HIF-1αprotein,MDR1 protein,MRP protein were examined by immunohitochemistry techenique in different groups. The mortality of cells were observed by MTT in different groups coped with cisplatin of different concentrations.Results: (1)The expression of HIF-1αmRNA of different groups were 0.49±0.01, 0.97±0.01, 0.98±0.02, 0.57±0.05 seperately; the expression of MDR1mRNA of different groups were 0.30±0.01, 0.46±0.04, 0.48±0.02, 0.35±0.04 seperately; the expression of MRPmRNA of different groups were 0.21±0.01, 0.90±0.01, 0.91±0.02, 0.60±0.09 seperately; HIF-1αwered significantly related to MDR,MRP at the mRNA level. There were significant differences between different groups (P＜0.05). (2) The expression of the protein of HIF-1αin different groups were 2.57±0.36, 4.00±0.59, 4.02±0.14, 2.97±0.09seperately; the expression of the protein of MDR in different groups were 1.71±0.40, 2.92±0.55, 2.78±0.15, 2.18±0.15 seperately; the expression of the protein of MRP in different groups were2.31±0.39, 3.51±0.08, 3.49±0.11, 2.78±0.09 seperately; HIF-1αwered significantly related to MDR,MRP at the protein level. There were significant differences between different groups (P＜0.05). (3) The curve of cells' mortality were drawed by MTT, the torlerance of cisplatin were different in A549/DDPcells in different groups ,There were significant differences between different groups (P＜0.01). Therefore, A549/DDPcells'tolerance of cisplatin were significant decreased under the condition of lacking oxygen after transfection with HIF-1a siRNA.Conclusion: (1)Under the condition of low level oxygen, the expression of HIF-1α,MDR1,MRP were significant increased in A549/DDPcells of pulmonary carcinoma , and moreover the expression of HIF-1αwere positively related to the expression of MDR1,MRP significantly.(2) Under the condition of low level oxygen, A549/DDPcells'tolerance of cisplatin were significantly increased, which because of the increasing of HIF-1αupregulated the expression of MDR1,MRP possibly.(3) HIF-1αsiRNA can significantly downregulate the expression of HIF-1α,which perhaps significantly downregulate the expression of MDR1,MRP.(4) Under the condition of low level oxygen, A549/DDP cells' drug-resistance of cisplatin were significantly increased after transfection with HIF-1a siRNA, perhaps because the downregulation of HIF-1a downregulate the expression of MDR1,MRP.Accordingly, the study offer a new target for the clinical research of the tolerance of medicine in chemotherapy.