Mechanism and significance of apoptosis of the immortalized human oral mucosal epithelial cells established by Lentivirus-mediated hTERT.

During the transition from human oral mucosal epithelial cells (HOMEC) to oral squamous cell carcinoma cells (Cal27), the cells must have undergone a precancerous state. To explore the malignant rule of HOMEC, plv-HOMEC was used as a model cell for the precancerous state to investigate plv-HOMEC's apoptosis by comparing human oral mucosal epithelial cells established by Lentivirus-mediated hTERT (plv-HOMEC) with HOMEC and human Cal27. The lentiviral particles overexpressing hTERT were packaged and transfected into primary HOMEC to obtain plv-HOMEC. Expression levels of NF-κB were detected in the cytoplasm and nucleus of Cal27, plv-HOMEC and HOMEC. The level of intracellular reactive oxygen species was measured to verify the endoplasmic reticulum pathway, cytochrome C expression was detected to verify the mitochondrial pathway, and FasL gene expression was detected to verify the death receptor apoptosis pathway. The total expression of NF-κB in plv-HOMEC increased, mainly due to the greater nuclear import of NF-κB, but it was still much lower than Cal27. The endoplasmic reticulum apoptosis pathway of plv-HOMEC was not significantly affected, and there were no significant differences between them and the HOMEC cells; the mitochondrial apoptosis pathway of plv-HOMEC was inhibited, and the expression of Cyt C was very close to that of Cal27, indicating that the characteristics of plv-HOMEC are so familiar with cancer cells; the death receptor apoptosis pathway of plv-HOMEC was also inhibited, and in this apoptotic pathway, plv-HOMEC were more similar to cancer cells than to HOMEC cells. The present data suggest that NF-κB nucleation may increase in the early stage of healthy cells' carcinogenesis, followed by inhibition of the mitochondrial pathway and the death receptor apoptotic pathway.