TY - JOUR
T1 - 8-Cl-adenosine induces growth arrest without differentiation of primary mouse epidermal keratinocytes
AU - Dransfield, Daniel T.
AU - Griner, Richard D.
AU - Ray, Sagarika
AU - Keskintepe, Meral
AU - Bollag, Wendy B.
N1 - Funding Information:
W.B.B. is supported by NIH (NIAMS) grant AR45212. D.T.D. was supported by grants from the Medical College of Georgia Research Institute and the American Digestive Health Foundation.
PY - 2001/12
Y1 - 2001/12
N2 - In some cell systems, the antiproliferative effects of 8-Cl-cAMP, a site-selective cAMP analog specific for the type I cAMP-dependent protein kinase, are mediated by its metabolite, 8-Cl-adenosine. These effects were once thought to be specific to transformed cells. We investigated the ability of 8-Cl-adenosine to regulate growth and differentiation in primary cultures of mouse epidermal keratinocytes. A 24 h exposure of keratinocytes to 8-Cl-adenosine inhibited [3H]thymidine incorporation in a dose-dependent manner with an apparent IC50 of 7.5 μM, and these effects were completely reversible. To determine the ability of 8-Cl-adenosine to induce differentiation of primary keratinocytes, we measured keratin-1 expression and transglutaminase activity, markers of early and later stages of keratinocyte differentiation, respectively. Interestingly, exposure of keratinocytes to 25 μM 8-Cl-adenosine for 24 h had no effect on keratin-1 expression or transglutaminase activity. The 8-Cl-adenosine-induced growth arrest of keratinocytes required uptake of the compound and was accompanied by an increase in protein expression of the cyclin-dependent protein kinase inhibitor p21 WAF1/Cip1. These results demonstrate that 8-Cl-adenosine inhibits growth in a nontransformed/non-immortalized cell system, possibly through an elevation in p21WAF1/Cip1 protein levels, without inducing differentiation.
AB - In some cell systems, the antiproliferative effects of 8-Cl-cAMP, a site-selective cAMP analog specific for the type I cAMP-dependent protein kinase, are mediated by its metabolite, 8-Cl-adenosine. These effects were once thought to be specific to transformed cells. We investigated the ability of 8-Cl-adenosine to regulate growth and differentiation in primary cultures of mouse epidermal keratinocytes. A 24 h exposure of keratinocytes to 8-Cl-adenosine inhibited [3H]thymidine incorporation in a dose-dependent manner with an apparent IC50 of 7.5 μM, and these effects were completely reversible. To determine the ability of 8-Cl-adenosine to induce differentiation of primary keratinocytes, we measured keratin-1 expression and transglutaminase activity, markers of early and later stages of keratinocyte differentiation, respectively. Interestingly, exposure of keratinocytes to 25 μM 8-Cl-adenosine for 24 h had no effect on keratin-1 expression or transglutaminase activity. The 8-Cl-adenosine-induced growth arrest of keratinocytes required uptake of the compound and was accompanied by an increase in protein expression of the cyclin-dependent protein kinase inhibitor p21 WAF1/Cip1. These results demonstrate that 8-Cl-adenosine inhibits growth in a nontransformed/non-immortalized cell system, possibly through an elevation in p21WAF1/Cip1 protein levels, without inducing differentiation.
KW - Cell cycle
KW - Keratin-1
KW - P21
KW - Transglutaminase
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U2 - 10.1046/j.0022-202x.2001.01572.x
DO - 10.1046/j.0022-202x.2001.01572.x
M3 - Article
C2 - 11886527
AN - SCOPUS:0035674541
SN - 0022-202X
VL - 117
SP - 1588
EP - 1593
JO - Journal of Investigative Dermatology
JF - Journal of Investigative Dermatology
IS - 6
ER -