Abstract:

Objective

To study the role of protein kinase C-θ （PKC-θ） in apoptosis in human tongue squamous cell carcinoma Tca8113 cell lines after transfected by nm23-H1 gene.

Methods

Tca8113 ce11s were transfected with pAdEasy-nm23-H1 by lipofection. The cells were pretreated with Calphostin C， a PKC-θ specific suppressor and DMSO for 30 minutes， the morphologic changes of the cells were observed under inverted microscope after routine culture of 24 hours. Apoptotic ratio was detected by flow cytometry. Activation and cleavage of PKC-θ were examin-ed by Western-blotting.Relative activities of Caspase-3 were studied with ELISA.

Results

The expression of PKC-θ was found translocating from cytoplasm and perinucleus to nucleus in Tca8113 cells after transfected with nm23-H1 gene. Gene transfection of nm23-H1 could induce PKC-θ activation and formed functional catalytic fragment， but Calphostin C played a suppressive role. The relative activity of Caspase-3 and apoptotic ratio were increased in both Calphostin C pretreated and DMSO pretreated group after transfected with nm23-H1 gene， and the differences were significant statistically （P＜0.05）.

Conclusions

The results of this study suggest that activation and cleavage of PKC-θ， which were induced by gene transfection of nm23-H1， played a role in the process of Tca8113 cells apoptosis. Activation of Caspase-3 by PKC-θ maybe one of the mechanism of tumor cells apoptosis induced by nm23-H1.

Key words: Nm23-H1 gene, Protein kinase C-θ, Caspase-3, Translocation, Apoptosis