TY - JOUR
T1 - Role of calcium in the regulation of ornithine decarboxylase enzyme activity in mouse colon cancer cells
AU - Ishizuka, Jin
AU - Bold, Richard J.
AU - Townsend, Courtney M.
AU - Thompson, James C.
N1 - Funding Information:
This work was supported by NIH grants (5R37 DK15241 and POI DK35608), the American Cancer Society (CB-571). Walls Medical Research Foundation, and the John Sealy Memorial Research Endowment Fund.
PY - 1995
Y1 - 1995
N2 - Activity of ornithine decarboxylase (ODC), one of the rate-limiting enzymes in the pathway of polyamine biosynthesis, is regulated by various factors. In this study, we examined the role of Ca2+ in the regulation of ODC enzyme activity in mouse colon cancer cells (MC-26). KCl, a membrane-depolarizing agent that opens the voltage-dependent Ca -channel to increase intracellular Ca2+, decreased serum-induced ODC enzyme activity in MC-26 cells in a dose-dependent, reversible fashion. Both verapamil and nifedipine, inhibitors of the L-type voltage-dependent Ca2+-channel, decreased serum-induced ODC enzyme activity. W-7, a calmodulin inhibitor, decreased ODC enzyme activity in a dose-dependent, reversible fashion while trifluoperazine, another calmodulin inhibitor, failed to affect ODC enzyme activity in MC-26 cells. Our findings indicate that intracellular Ca participates in the regulatory mechanism of ODC enzyme activity in MC-26 cells, although the exact role of Ca2+ is still unclear.
AB - Activity of ornithine decarboxylase (ODC), one of the rate-limiting enzymes in the pathway of polyamine biosynthesis, is regulated by various factors. In this study, we examined the role of Ca2+ in the regulation of ODC enzyme activity in mouse colon cancer cells (MC-26). KCl, a membrane-depolarizing agent that opens the voltage-dependent Ca -channel to increase intracellular Ca2+, decreased serum-induced ODC enzyme activity in MC-26 cells in a dose-dependent, reversible fashion. Both verapamil and nifedipine, inhibitors of the L-type voltage-dependent Ca2+-channel, decreased serum-induced ODC enzyme activity. W-7, a calmodulin inhibitor, decreased ODC enzyme activity in a dose-dependent, reversible fashion while trifluoperazine, another calmodulin inhibitor, failed to affect ODC enzyme activity in MC-26 cells. Our findings indicate that intracellular Ca participates in the regulatory mechanism of ODC enzyme activity in MC-26 cells, although the exact role of Ca2+ is still unclear.
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U2 - 10.3109/07357909509011688
DO - 10.3109/07357909509011688
M3 - Article
C2 - 7874572
AN - SCOPUS:0028950463
SN - 0735-7907
VL - 13
SP - 181
EP - 187
JO - Cancer Investigation
JF - Cancer Investigation
IS - 2
ER -