Study On The Mechanism And Application Of EBV Lytic Infection Induced By Cordycepin And Doxorubicin

Epstein-Barr virus is a human gamma herpesvirus discovered in 1964,and it can establish persistent infection in more than 95%population for life.EBV is the first discovered tumor associated virus.Two hundred thousand new cases of EBV associated cancers are reported worldwide each year,and about 1.8%of cancer deaths are caused by EBV related tumors.Immunosuppressive and immunocompromised populations is more susceptible to EBV positive tumors.Compared with the developed areas,the incidence of EBV associated tumors is higher in developing countries.China is a country with high incidence of EBV positive cancers,especially nasopharyngeal carcinoma and gastric cancer,which poses a great threat to human health.In EBV positive tumors,EBV exists in latent infection,EBV is also a cytolytic virus,which offers the potential for the cytolytic virus-targeted therapies.Many chemotherapeutic agents can reactivate EBV into cytolytic cycle,and a series of clinical studies have shown that cytolytic virus activation(CLVA)therapy is effective in patients with EBV positive tumors,which can improve the quality of life and prolong the survival time of patients.However,the clinical drugs that can induce lytic EBV infection are limited.Therefor,it is urgent to study new drugs for the treatment of EBV positive tumors.Cordycepin is a natural small molecular compound extracted from traditional Chinese medicine Cordyceps sinensis,and it has been reported to have a lot of biological effects such as anti-inflammatory and anti-tumor effect.Here,we found that cordycepin induced EBV lytic infection through p38 MAPK,PKC and MEK signaling pathways in tumor cells,and had certain selective killing effect on EBV positive tumor cells.We then demonstrated that cordycepin significantly enhanceed the EBV lytic infection activating effect of traditional chemotherapeutic drug doxorubicin.Cordycepin also significantly enhance the ability of doxorubicin to kill EBV positive tumor cells.We further showed that the combination use of cordycepin and doxorubicin activated the transcription of EBV immediate early gene BZLF-1 through PKC-p38 MAPK signaling pathways.Furthermore,we showed that cordycepin and doxorubicin had synergistic effect on activate transcription factor C/EBP? through PKC-p38 MAPK pathways.The luciferase reporter assay and siRNA knockdown experiment showed that the activation of BZLF-1 and the induction of lytic EBV infection were mediated by C/EBP?.Finally,using the in-vivo animal model,we showed that the combination use of cordycepin and doxorubicin had obvious therapeutic effect on EBV positive tumors,and cordycepin significantly slowed the mouse body weight loss caused by doxorubicin.These results indicate that natural small molecular compound cordycepin can active EBV lytic infection,and the combination use of cordycepin and traditional chemotherapeutic drug doxorubicin has a synergistic effect on activating EBV lytic infection.In addition,our study also illustrates that the combination use of cordycepin and doxorubicin can activate EBV lytic infection through PKC-p38 MAPK-C/EBP? signaling pathway.And most importantly,the combined use of cordycepin and doxorubicin has significant therapeutic effect on treating EBV positive tumors in mouse model.These results will provide an important reference for the treatment of EBV positive tumors.