The Mechanism Of DNAzyme Influence Angiogenesis Enhanced Radiosensitvity Of Nasopharyngeal Carcinoma

As we all known, HIF-1(hypoxia inducible factor-1) plays a key role in responding to hypoxia. Through oxygen-dependent or independent way, many upstream genes in tumor cells could regulate the expression of HIF-1, further participating in many other tumor biologic processes. Vascular endothelial growth factor (VEGF) is one of the most important target genes of HIF-1, and also a crucial molecular regulating tumor angiogenesis. Studies have shown that the relationship between angiogenesis and radiosensitive is significantly close. Clinical data has indicated that radiotherapy is the main therapy method for Nasopharyngeal Carcinoma and the radition resistance often causes tumor recurrence and metastasis. The development and progression of NPC is closely related with EBV infection. As a oncogenic protein, EBV encoded LMP1plays an important role in this process, which suggests that LMP1may be a pivotal targrt gene for NPC therapy. DNAzyme is an efficient and specific strategy targeted to gene therapy. In the early study we found that LMP1-targeted DNAzyme can enhance the radiosensitivity of NPC, but the mechanism is not very clearly. In this paper, First, we ultilize tubular formation experiment to improved that DZ1specific targeted to latent membrane protein1(LMP1) could inhibit the secretion of VEGF in tumor cells. Then, we use various phosphokinase inhibitor to screen the probable signal pathway, by which LMP1can modulate the expression of VEGF, demonstrating that LMPl could influence VEGF expression through c-Jun N-terminal protein kinase (JNK)/HIF-1pathway; Afterwards we use reporter gene experiment and Western Blot to demonstrate that DZ1could influence HIF-1transcription activity, which is depended on the phosphonation of JNK. We use NPC clinical samples to do Immunohistochemistry and further confirmed that the level of expression between LMPl and JNK, HIF-1,VEGF is positively correlated. Then we obersved the ability of tumor cells’clony formation, which demonstrated that DNAzyme1(DZ1) could enhance the radiosensitivity of NPC. In addition to this, we use the Bioluminescent imaging technology to detect the growth of xenograft at real time and to observe the influence of DZ1on radiosensitivity of tumor cells. Moreover, we perform the Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to prove the role of DZ1on xenograft’s vascular permeability, confirming that DZ1could inhibit angiogenesis and enhance the radiosensitivity of tumor cells.In conclusion, through this study, we demonstrated that LMP1can promote tumor cells’radiation resistance, while DZ1specific targeted LMP1can influence angiogenesis, further enhancing radiosensitivity of NPC through JNK/HIF-1pathway.