Study On The Effects And Mechanism Of Overexpressed HTERT To The Apoptosis Pathways Of Human Oral Mucosal Epithelial Cells

Background:Oral squamous cell carcinoma is the most common seen cancer in stomatology,and a large part of it is caused by oral mucosal disease.After normal oral mucosal epithelial cells are stimulated by the environment or physical and chemical factors,some cells become cancerous and then came the oral squamous cell carcinoma.Nuclear factor kappaB plays an important role in the antagonism of apoptosis in tumor cells,it increased the immortalization ability of cancer cells.Human telomerase reverse transcriptase is an endogenous gene that increases cell passage ability by extending telomeres,and it promotes interaction with NF-?B,and the interaction between them enhances cells' ability of immortalization.Immortalized nasopharyngeal epithelial cells have been identified as a cellular state in the early stage of nasopharyngeal carcinoma.Human immortalized oral mucosal epithelial cells are transformed from normal cells,at the same time they have the immortalization ability of cancer cells.It is believed that they might be the intermediate process of normal cells to cancer cells,and exploring its apoptotic pathway will help to further understand the process of normal cell carcinogenesis,provides new ideas for the prevention and treatment of oral squamous cell carcinoma.Objective: Investigating plv-HOMEC's apoptosis by comparing human oral mucosal epithelial cells established by lentivirus-mediated hTERT(plv-HOMEC)with normal human oral mucosal epithelial cells(HOMEC)and human oral squamous carcinoma cells(Cal27).It provides a new idea for the mechanism of apoptosis of the transformation process of normal cells to cancer cells.Methods: The tissue excised during the first-stage operation of the children with cleft lip was obtained,after a series of operations,the primary oral mucosalepithelial cells were isolated and cultured.The lentiviral particles overexpressing hTERT were packaged and transfected into primary HOMEC to obtain plv-HOMEC.The expression levels of NF-?B in cytoplasm and nucleus of Cal27,plv-HOMEC and HOMEC was detected.The expression of intracellular reactive oxygen species was measured to verify the endoplasmic reticulum pathway,the expression of cytochrome C was detected to verify the mitochondrial pathway,and the FasL gene expression was detected to verify the death receptor apoptosis pathway.Results: The total expression of NF-?B in plv-HOMEC increased compared with HOMEC,it's mainly due to its increased nuclear import,but the expression of them are still much lower than Cal27.The endoplasmic reticulum apoptosis pathway of plv-HOMEC was not significantly affected,and there was no significant difference between them and normal cells;the mitochondrial apoptosis pathway of plv-HOMEC was inhibited,and the expression of Cyt C was very close to that of Cal27,showing that the characteristics of plv-HOMEC are so familiar with cancer cells;plv-HOMEC's death receptor apoptosis pathway is also inhibited,and plv-HOMEC is more alike cancer cells in this apoptotic pathway than normal cells.Conclusion: The nucleation of NF-?B has increased in plv-HOMEC,and then inhibited the mitochondrial pathway and the death receptor apoptosis pathway,resulting in its' ability to be stable and efficiently cultured.It is suggested that in the early stage of normal cells' carcinogenesis,there may be an increase in NF-?B nucleation,followed by inhibition of mitochondrial pathways and death receptors pathway.Decreasing the content of Cyt C in the cytoplasm allows the cells to obtain a better internal environment,and the decreased expression of FasL weakens the influence of external stimuli on cells,and promotes the cells in the precancerous state to further transform into cancer cells.