Phosphatidylinositol triphosphate kinase-dependent and c-jun NH2-terminal kinase-dependent induction of telomerase by calcium requires Pyk2.

Calcium signaling has been linked to activation of Pyk2, a calcium-dependent, focal adhesion kinase-related, non-receptor tyrosine kinase. Signaling via Pyk2 can activate c-jun NH(2)-terminal kinase (JNK). Calcium has also been shown to activate phosphatidylinositol triphosphate kinase and/or JNK.

Telomerase is regulated by c-Jun NH2-terminal kinase in ovarian surface epithelial cells.

Telomerase activity is present in >90% of all tumors and appears to be regulated by the phosphatidylinositol 3-kinase signaling pathway. Here we demonstrate that Akt is not involved in the signaling cascade for telomerase regulation in ovarian surface epithelial cells. However, we showed that c-Jun NH2-kinase induces telomerase activity, that inhibition of JNK by JIP abrogates telomerase activity, and that JNK expression activates transcription of a reporter gene fused to the hTERT promoter sequence.

Calcium-mediated telomerase activity in ovarian epithelial cells.

Though the potential of telomerase as an anti-cancer target is evident, information about regulation of telomerase remains fragmentary. In the present study, we examined the role of calcium, an essential cellular signaling molecule, in the regulation of telomerase. We found that calcium induced de novo telomerase activity in telomerase-negative ovarian surface epithelial (OSE) cell lines but not in primary cultures of OSE.