| Objective To approach the association between the mRNA expression ofASPP family genes and cisplatin chemotherapy sensitivity in gastric cancercells of different p53genetic background. To approach the influence ofcisplatin chemotherapy sensitivity to gastric cancer cells of different p53genetic background after the mRNA expression of iASPP weredownregulated.Methods （1）Gastric cancer cell lines AGS (wild-type p53) andSGC-7901(mutant-type p53) with different p53genetic background weretreated with different concentrations of cisplatin, and measured the cell linesinhibition ratio after24hours,48hours and72hours by MTT assay. ThemRNA expression of ASPP family genes in gastric cancer cell lines AGS andSGC-7901were detected by RT-PCR,and analysed the association betweenthe mRNA expression of ASPP family genes and cisplatin chemotherapysensitivity.（2）Short hairpin RNAs (shRNAs) that target iASPP were constructed,and transfected into gastric cancer cell lines AGS and SGC-7901. Theexpression alteration of iASPP were detected by RT-PCR. （3）The mRNA expression of iASPP in gastric cancer cell lines AGSand SGC-7901were downregulated，and the cell lines were treated withcisplatin,then the inhibition rate were measured by MTT assay,the apoptosisrate by flow cytometry.Results（1）Compared with the control group,the cell proliferation wasslowed down in gastric cancer cell lines AGS and SGC-7901when treatedwith different levels of cisplatin(P<0.05). The cell lines treated with cisplatinafter24hours,48hours and72hours,the inhibition ratios of AGS were lowerthan SGC-7901（P<0.05）,the IC50of AGS were higher than SGC-7901（P<0.05）. Compared with the mRNA expression of ASPP family genes inAGS and SGC-7901, the mRNA expression of ASPP2in AGS was lower thanin SGC-7901（P<0.05）, the mRNA expression of iASPP in AGS was higherthan in SGC-7901（P<0.05）, the mRNA expression of ASPP1wasundifferentiated（P>0.05）.（2）Recombinant plasmid vector expressing iASPP was successfullyestablished，compared to the group of HK and KB，the mRNA expressioniASPP identified by RT-PCR were significantly inhibited by iASPP-shRNA inAGS and SGC-7901cells（P<0.05）.（3）The cell lines treated with cisplatin（3.00μg/ml）after24hours, theinhibition rate of AGS-iASPP-shRNA was higher than that of AGS-KB,whilethe inhibition rate of SGS-7901-iASPP-shRNA was higher than that of SGC-7901-KB（P<0.05）.The cell lines treated with cisplatin（3.00μg/ml）after24hours, the apoptosis rate of AGS-iASPP-shRNA was higher thanthat of AGS-KB, while the apoptosis rate of SGC-7901-iASPP-shRNA washigher than that of SGS-7901-KB（P<0.05）. The apoptosis rate D-valuebetween AGS-iASPP-shRNA and AGS-KB was significantly higher than thatbetween SGC-7901-iASPP-shRNA and SGS-7901-KB（P<0.05）.Conclusion The cisplatin chemotherapy sensitivity of AGS was lowerthan that of SGC-7901.Compared to the mRNA expression of ASPP familygenes in SGC-7901, ASPP2in AGS was lower,iASPP in AGS was higher,ASPP1was undifferentiated. The iASPP expression level can influence thecisplatin resistance of gastric cancer cells.The iASPP expression level ishigher,the cisplatin sensitivity is the lower,more significantly in AGS. |
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