Alcohol modulates TPA induced JNK/SAPK activity in HPV16E6E7 immortalized oral keratinocyte

Methods: Normal human oral keratinocytes were immortalized using human papillomavirus type 16 E6 and E7 by retrovirus-mediated transfection (HOK16E6E7). HOK16E6E7 was then treated with physiological concentration of alcohol alone or in conjunction with 100 ng/ml TPA. JNK/SAPK activity was assessed using glutathione S-transferase affinity matrix binding assay in vitro using GST-c-jun (1-79 aa) as a substrate. Electrophoretic mobility shift assays were conducted to measure c-jun binding activity.

Results: Alcohol from 0 to 100 mM had no effect on JNK/SAPK activity. TPA induction of HOK16E6E7 at 100 ng/ml caused a slight transient elevation of JNK after 30 min of induction. However, the inclusion of alcohol potentiated the effect of TPA and resulted in enhanced phosphorylation of GST-c-jun. The dual treatment also increased c-jun binding to AP-1 site.

Conclusions: The data suggested the possibility of alcohol in tumor promotion in the oral mucosa by increasing c-jun activity through the JNK/SAPK pathway.