Differentially expressed genes associated with apoptosis in human rhabdomyosarcoma cells infected by enterovirus 71
Objective To explore the different apoptotic gene expressions and apoptotic signaling transduction of human rhabdomyosarcoma (RD) cells infected by enterovirus 71 (EV71) in different stage.Methods The survival of EV71-infected RD cells was observed by trypan blue staining.The apoptotic morphology and rates of RD cells were surveyed and detected by Annexin V-FITC/PI staining and flow cytometry,respectively.PCR array was employed to analyze 88 apoptotic gene expressions from EV71-infected RD cells at 8 h and 20 h postinfection (p.i),respectively.Results After RD cells were infected with EV71 (MOI =5) at 8 h p.i,the viability was significantly decreased.Flow cytometry data demonstrated that the apoptotic rates of EV71-infected RD cells had increased to 18.0％ and 19.1％ at 20 h p.i in early and later stage respectively.RT-PCR array studies revealed significant variations in the expression of apoptotic genes.Among 88 genes,only the expression of IFN-β1 was upregulated 5.22 folds,whereas 47 genes including ACIN1,Akt,Apaf1,caspase and CIDEB were found to be downregulated that were lower than 2 folds at 8 h p.i.However,28 genes including FasL,CD40L,TNF,caspase-10 and caspase-3 were induced more than 2 folds after EV71 infection at 20 h.Conclusion The downregulation of apoptosis-related genes is associated with viral apoptosis-suppressing effect in RD cells in the early stage of EV71 infection.The death receptor signaling pathways including Fas/FasL and TNF/TNFR are activated to induce cell apoptosis in the late stage of EV71 infection.Moreover,host cell can also inhibit apoptosis by regulating signal pathway of CD40/CD40L,NF-κB/RelA and PI3K/Akt activation. 
 
Key words: 
Enterovirus 71;  RT-PCR array;  FasL;  CD40L;  Apoptosis