These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Differential regulation by anti-tumor-promoting 12-deoxyphorbol-13-phenylacetate reveals distinct roles of the classical and novel protein kinase C isozymes in biological responses of primary mouse keratinocytes.
    Author: Szallasi Z, Kosa K, Smith CB, Dlugosz AA, Williams EK, Yuspa SH, Blumberg PM.
    Journal: Mol Pharmacol; 1995 Feb; 47(2):258-65. PubMed ID: 7870033.
    Abstract:
    12-Deoxyphorbol-13-phenylacetate (dPP) is the prototype for a new class of phorbol derivatives that function as protein kinase C (PKC) activators with potent anti-tumor-promoting activity. To explore the mechanism of action of dPP, we have conducted detailed analyses of the translocation and down-regulation patterns of individual PKC isozymes in mouse primary keratinocytes upon dPP treatment. PKC-alpha, -delta, and -epsilon were very quickly (within 2-5 min) translocated from the soluble fraction to the Triton X-100-soluble particulate fraction. PKC-delta and -epsilon were translocated with 2 orders of magnitude higher potency than was PKC-alpha. After translocation, PKC-alpha, -delta, -eta, and -epsilon were down-regulated; the down-regulation of PKC-epsilon contrasts with its retention after phorbol-12-myristate-13-acetate or bryostatin treatment. As was the case with translocation, dPP down-regulated the novel PKC isozymes (delta, epsilon, and eta) with 2 orders of magnitude higher potency (ED50, about 1-2 nM), compared with PKC-alpha (ED50, about 100 nM). dPP induced transglutaminase activity, ornithine decarboxylase activity, and cornification with potencies similar to that for PKC-alpha translocation. On the other hand, dPP caused inhibition of EGF binding with a potency similar to that for the translocation of the novel PKC isozymes. Although the generality of its selectivity in different cell types remains to be determined, at least in keratinocytes dPP is a powerful tool for dissecting the involvement of the classical and novel PKC isozymes in biological responses. The unique regulatory pattern of PKC-epsilon could contribute to the anti-tumor-promoting activity of dPP.
    [Abstract] [Full Text] [Related] [New Search]