Protein kinase C delta is activated in mouse ovarian surface epithelial cancer cells by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).
Interactions between the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and protein kinase C (PKC) signaling pathways are governed in cell and tissue-specific manners, albeit the physiological significance of which is unclear. This research sought to define the effects of TCDD on the PKC pathway using a mouse ovarian surface epithelial cancer cell line (ID8). Phorbol-12-myristate-13-acetate (PMA) potentiated (1 nM) TCDD-induced 7-ethoxyresorufin-O-deethylase (EROD) activity after 24h of treatment, and pre-treatment with (1 microM) of either a general PKC inhibitor (BisI) or PKCdelta-specific inhibitor (Rotterlin) abolished the potentiation indicating that activation of PKC enhances TCDD signal transduction. Western blot analysis revealed that unstimulated ID8 cells express PKCalpha, beta, epsilon, tau, lambda and RACK1. PKCgamma, eta, theta and DGKtheta were not detected. TCDD (1 nM) increased PKCdelta protein approximately eight-fold after 24h of treatment and this effect was dose-dependent (0.1-100 nM); other PKC isoforms and related signaling proteins tested were unaffected by TCDD treatment. Immunofluorescent microscopy revealed that TCDD (1 nM) promoted the subcellular redistribution of PKCdelta, from the cytoplasm and the nucleus to the perinuclear area after 2h of treatment, however, after 24h of treatment PKCdelta was observed in nuclear structures that resembled nucleoli. TCDD (1 nM) also increased total PKC and PKCdelta-specific kinase activities in biphasic time-responsive manners. Total PKC and PKCdelta-specific activities increased after 1-2h of treatment. Then TCDD increased the total PKC activity again after 12h of treatment, whereas, PKCdelta-specific activity resurged at 24h and remained elevated at 48 h after treatment. The results indicate that TCDD preferentially induces PKCdelta protein expression and phosphotransferase activity, and its membrane translocation, indicating a potential intracellular role for PKCdelta as an effector molecule for TCDD-mediated biological events in this ovarian cancer cell line.
Williams
Shalmica R
SR
Department of Molecular and Integrative Physiology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA.
Son
Deok-Soo
DS
Terranova
Paul F
PF
D000818:Animals; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D003001:Cloning, Molecular; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000633:toxicity*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects* / Q000201:enzymology; D005260:Female; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D051379:Mice; D008810:Mice, Inbred C57BL; D010051:Ovarian Neoplasms / Q000473:pathology; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051745:Protein Kinase C-delta; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014407:Tumor Cells, Cultured
D004785:Environmental Pollutants; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D000072317:Polychlorinated Dibenzodioxins; C497259:Prkcd protein, mouse; D011493:Protein Kinase C; D051745:Protein Kinase C-delta