STRUCTURAL AND FUNCTIONAL CHARACT ERISTICS OF THE LMP1 ONCOGENE IN PATIENTS WITH TUMORS ASSOCIATED AND NOT ASSOCIATED...

Epstein-Barr virus (EBV) - the etiological agent of a number of human benign and malignant tumors including infectious mononucleosis (IM), Burkitt lymphoma (BL), Hodgkin (HL) and non-Hodgkin (NLH) lymphomas, nasopharyngeal carcinoma (NPC), and many other tumors. Latent membrane protein 1 (LMPl) encoded by the gene of the same name (LMP I) is the main oncoprotein of EBV. LMP1 is a transmembrane protein capable of activating many signaling pathways and transcription factors of the cells, which leads to its transformation. Molecular analysis of LMP1 of various clinical origins identified many variants with different types of amino acid mutations that influence its biological activity. Since the role of LMPl in the development of NPC is still not fully understood, it is important to find out how LMPl samples from patients with EBV-associated form of NPC differ from those of patients with other tumors also located in the oral cavity (OTOC), but not associated with this virus. Unlike most investigations conducted in endemic regions, the present work is intended to compare the genetic structure and the transforming activity of LMPl variants from NPC and OTOC patients has been carried out in a non-endemic region of Russia, where NPC is rarely diagnosed. The obtained data show structural and functional similarities of LMP1 variants in the two groups of patients and, accordingly, a genetic relationship of EBV strains persisting in these patients. Our work suggests that in non-endemic regions any EBV strain with any structure of LMP1 may become the etiologic agent of NPC. However, based on modem concepts, the cancer can occur only if EBV-infected persons have a unique pattern of HLA associated with a high sensitivity to the development of NPC combined with exposure to harmful environmental factors (chemical or physical carcinogens) and lifestyle.