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Regulation of cell‐cell communication in rat bone cells: The effect of phorbol esters
Author(s) -
Massass Ruth,
Mittelman Leonid,
Korenstein Rafi
Publication year - 1999
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(19990901)74:3<349::aid-jcb4>3.0.co;2-5
Subject(s) - ionomycin , intracellular , calcium in biology , calcium , intracellular ph , chemistry , cytosol , phorbol , microbiology and biotechnology , endocrinology , biophysics , protein kinase c , medicine , biochemistry , biology , signal transduction , enzyme , organic chemistry
The skin tumor promoter 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) is a potent inhibitor of gap junctional intercellular communication. In the present study, the inhibition of cell‐cell communication by TPA has been investigated in primary bone cells from newborn rat calvaria, with an emphasis on the involvement of intracellular pH (pH i ) and cytosolic calcium ([Ca +2 ] i ) in this process. The results show that TPA (5 × 10 − 8 M) caused a complete inhibition of intercellular communication within 40–60 min. The intercellular communication was fully restored after overnight incubation in the presence of TPA. This effect was found to be associated with an elevation of pH i . However, neither an increase of pH i alone nor exposure to TPA, under conditions preventing pH i ‐shift, were found to affect intercellular communication. It is suggested that the inhibition of intercellular communication, in the presence of TPA, depends on the pH i ‐shift itself rather than on the absolute value of pH i . In addition, elevation of cytosolic calcium by ionomycin led to the termination of intercellular communication after 30 min. This inhibitory effect was abolished when the cells were incubated for overnight with TPA and then intracellular calcium was elevated by the addition of ionomycin. These results indicate that shift of pH i and the increase of intracellular calcium are involved in repression of intercellular communication by TPA. J. Cell. Biochem. 74:349–356, 1999. © 1999 Wiley‐Liss, Inc.