Study On Cell Cycle Arrest Induced By Newcastle Disease Virus

Newcastle disease(ND)is a deadly infectious disease of poultry caused by the Newcastle disease virus(NDV)that may results significant economic losses in the poultry industry.NDV could also replicated in tumor cells,causing tumor cell apoptosis.At present,NDV has been used as a tool for human cancer treatment.In our previous study,we noted that NDV infection in the logarithmic growth phase of the cells,the cell growth will immediately stop,and after 24 hours,a large number of cells die from apoptosis on anticancer drug development.Therefore,the study of the relationship between NDV infection and cell cycle,will not only help us in understanding the mechanisms of virus proliferation post invasion but also help us in understanding more about the mechanisms underlying the preferential killing of cancer cells by NDV,and eventually will provide a more in-depth theoretical basis on anticancer drug development.In this study,NDV was used to infect HeLa cells.The cells were stained at different time points.Flow cytometry was used to detect the distribution of cell cycle.The results showed that the cell cycle was arrested in GO/G1 phase after NDV infection.On the basis of determining the effect of NDV infection on the cell cycle,the changes of cell cycle after UV UV irradiated NDV infection were detected.The results showed that the cell cycle arrest induced by NDV infection was dependent on the ability of virus replication in cells.The following experiments were performed by using NDV infected cells,which were treated at different time points,and analyzed by flow cytometry to detect the effect of the virus on the cell cycle.The results showed that NDV caused changing at 16 h after infection.Finally,avian cells(DF-1 and CEF cells)were infected with NDV.The results showed that NDV infection could also induce the avian cells arresting in GO/G1 phase.In this study,,the molecular mechanism of cell cycle arresting was analyze.The infected cells were detected with Western Blot,to analyze the phosphorylation of Rb protein and expression of cyclin D1 etc.Our data showed that cyclin D1,cyclin El,which are important in the transition from G1 to S,were down regulation,and confirmed the cell cycle arrest in the GO/G1 phase.Then we further explored the signal pathway associated with cyclin D1 regulation,the results showed that ?-catenin directly regulated the transcription level of cyclin D1.In this study,the the effect of cell cycle arresting on NDV proliferatio was further studied.The cells were synchronized into G0,G1,G2 and M phases,repectively,by means of starvation or drug treatment.The non-synchronized cell control was established in parallel.Each group was infected after 24 hours of infection,the cell supernatant was collected and the virus titer in the supernatant was examined,then data was analyzed.Proteins were extracted,and the expression of NP protein was analyzed by Western Blot,and the data of Western Blot were quantified and analyzed,to determine the virus proliferation in different phase of cell cycle.The results showed that cell cycle arrest in G0/G1 phase would favor viral replication.The aim of this project is to clarify the mechanism by which NDV infection affect cell cycle performance through the relationship between NDV infection and host cell cycle regulator molecules.In addation,the effect on virus proliferation was also determined in each phase of cell cycle.With this NDV-induced cell cycle arrest research model,we can understand more about virus-induced cell cycle,which would provide the theoretical and experimental basis for the study of the basic research and the application of tumor therapy.