Influence of ATP on Ehrlich Ascites Carcinoma Cell Free Cytoplasmic Calcium Concentration in the Course of Tumor Growth

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T. N. Zamay and A. S. Zamay^*

Krasnoyarsk State University, Svobodny pr. 79, 660041 Krasnoyarsk, Russia; fax: (3912) 49-4726; E-mail: szamay@akadem.ru

^* To whom correspondence should be addressed.

Received October 11, 2005; Revision received May 19, 2006

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The changes in free cytoplasmic calcium concentration ([Ca²⁺]_in) and the effects of extracellular ATP on [Ca²⁺]_in have been studied in Ehrlich ascites carcinoma cells in the dynamics of their growth. The basal level of [Ca²⁺]_in and the effects of ATP on the ascites cells were determined by the stage of tumor growth and depended on the content of reactive oxygen species (ROS). The sharp increase in basal and ATP-induced elevation of [Ca²⁺]_in levels were observed at the 12th day of ascites cell growth. Inhibition of ROS formation by N-acetyl-L-cysteine decreased [Ca²⁺]_in and suppressed the cell reaction to ATP. We suggest that the increased sensitivity of the ascites cells to ATP observed on the 12th day may be also attributed to a decrease in ecto-ATPase activity.

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KEY WORDS: Ehrlich ascites adenocarcinoma, Ca²⁺, ATP, reactive oxygen species, ecto-ATPase

DOI: 10.1134/S0006297906100051

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