TGF-alpha and IGF-I effects on calcium ion transients in human breast cancer cells.
In order to evaluate the potential role of calcium as an intracellular messenger for IGF-I and TGF-alpha action on breast cancer cell proliferation, we determined whether these growth factors induce any change in [Ca2+]i using fura-2 loaded cells. The hormone independent BT-20 and MDA-MB-231 cells were refractory to the mitogenic actions of exogenously added IGF-I and TGF-alpha. TGF-alpha administration, however, stimulated [Ca2+]i transients in the BT-20 cells. IGF-I and TGF-alpha stimulated DNA synthesis in the MCF-7 and T47D cells. These growth factors did not, however, stimulate any changes in [Ca2+]i in these cells. These data support the idea that receptor-mediated phospholipid hydrolysis does not serve a major signalling function for driving human breast cancer cells into DNA synthesis.
Etindi
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R
Department of Medicine/Division of Endocrinology, Milton S. Hershey Medical Center, Hershey, PA 17033.
Manni
A
A
D000255:Adenosine Triphosphate / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D001943:Breast Neoplasms / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D004247:DNA / Q000096:biosynthesis; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D016211:Transforming Growth Factor alpha / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D016211:Transforming Growth Factor alpha; D007334:Insulin-Like Growth Factor I; D000255:Adenosine Triphosphate; D004247:DNA; D002118:Calcium