Effects Of TRAIL On Gastric Cancer And Treatment Effects Of TRAIL With Docetaxel On Gastric Cancer Drug Resistance

Part I Effects and mechanism of TRAIL on the gastric cancer cellsObjective: The aim of this part of study was to explore the role and mechanism of TRAIL on gastric cancer biological behavior.Methods: Routine cultured gastric cancer cell line SGC-7901 was treated with100?g/m L,200 ?g/m L and 500 ?g/m L for 12 h,24 h and 48 h as experiment groups,whereas the untreated SGC-7901 was set as the control group.The cell proliferation,cell apoptosis,cell invasion and migration and expression of Survivin and NF-?B was respectively examined by MTT assay,TUNEL staining,Transwell assay and Western-blotting.Results: Compared to the control group,the experiment groups that treated with a series concentration of TRAIL showed cell proliferation inhibition and statistical significance was found(p<0.05);TRAIL at 500 ?g/m L at 48 h showed statistically significant on cell proliferation viability,cell apoptosis promotion and decreased cell invasion and migration ability(p<0.05).In the experiment groups,the TRAIL treated gastric cancer cell SGC-7901 at 12 h,24 h and 48 h,showed time and dose dependent suppression of the expression of Survivin and NF-?B(p<0.05).Conclusions: TRAIL treatment could result in decreased cell proliferation,cell apoptosis promotion,cell invasion and migration suppression via inhibition of the expression of Survivin and NF-?B.Part II Effects of TRAIL on the expression of drug resistant genes in gastric cancer cell SGC7901/VCRObjective: The aim of this part of study was to explore the role of TRAIL on drug resistant gene including MDR1,DAPK1 and DAPK2,thereby providing preliminary experiment evidence to reverse the gastric cancer drug resistant and solve the multiple drug resistant problem in gastric cancer.Methods: Drug resistant gastric cancer cell line SGC-7901/VCR was treated with a series concentration of TRAIL at 50 ?g/m L,100?g/m L,200 ?g/m L and 400 ?g/m L for 48 h as experiment groups,whereas the untreated SGC-7901/VCR was set as the control group.The expression of m RNA of drug resistant gene including MDR1,DAPK1 and DAPK2 was examined by real time PCR.Meanwhile,the proteins of drug resistant gene including P-gp,DAPK1 and DAPK2.The difference on the expression of drug resistant genes at the treatment of TRAIL was compared with one way ANOVA.Results: The 90% inhibition concentration of TRAIL on cell proliferation was 200?g/L and this concentration was defined as the effective concentration.After treatment with different concentration of TRAIL(100-500 ?g/m L),the expression m RNA of drug resistant gene including MDR1,DAPK1 and DAPK2 and the proteins of drug resistant gene including P-gp,DAPK1 and DAPK2 showed a trend of decreasing with the increasing of the TRAIL concentration,and these inhibitory effects was TRAIL concentration dependent.Conclusions: TRAIL treatment could result in the expression m RNA of drug resistant gene including MDR1,DAPK1 and DAPK2,and the proteins of drug resistant gene including P-gp,LRP and GST-?,and these inhibitory effects was TRAIL concentration dependent.Part III Effects and mechanism of TRAIL and docetaxelcombination on gastric cancer cell SGC7901/VCRObjective: The aim of this part of study was to explore the role of TRAIL and docetaxel on the viability of SGC-7901/VCR cells and discuss related mechanisms.Methods: The cell viability and proliferation of drug resistant gastric cancer cell line SGC-7901/VCR was determined by MTT at the setting of a series concentration of TRAIL(50,100,200 and 400 ?g/m L)and docetaxel(0,0.625,1.25,2.5,5 and 10 ?g/m L)to screen sub-toxic concentration of TRAIL and platinum.The cell apoptosis was determined by flow cytometry at the sub-toxic dosage of TRAIL and platinum.The expression MDR1 m RNA and P-gp protein was determined by real time quantitative PCR and ELISA.Results: The 90% inhibition concentration of docetaxel on cell proliferation was 0.6?g/m L and this concentration was defined as the effective concentration.After treatment with different concentration of 200 ?g/m L TRAIL(100-500?g/m L)and 0.6 ?g/m L docetaxel,increased cell apoptosis was found compared to TRAIL or docetaxel alone.The expression MDR1 m RNA and P-gp protein wasdecreased at the condition of 200?g/m L TRAIL(100-500?g/m L)and 0.6 ?g/m L docetaxel compared to TRAIL or docetaxel alone.Conclusions: Combination effects of TRAIL and docetaxel treatment on the drug resistant gastric cancer cell line SGC-7901/VCR viability was mediated by the expression m RNA of drug resistant gene including MDR1 and the proteins of drug resistant gene including P-gp.