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Effects of hyperthermia on intracellular calcium concentration and responses of cancerous mammary cells in culture
Author(s) -
Furukawa Masahiko,
Enomoto KohIchi,
Kato Hirokazu,
Ishida Tetsuya,
Maeno Takashi
Publication year - 1992
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.290100403
Subject(s) - hyperthermia , bradykinin , calcium , intracellular , extracellular , biophysics , calcium in biology , chemistry , cycloheximide , membrane permeability , fura 2 , cell culture , endocrinology , medicine , biology , biochemistry , cytosol , membrane , enzyme , receptor , organic chemistry , genetics , protein biosynthesis
Effects of hyperthermia on the intracellular calcium concentration (Ca i ) of an established mouse breast cancer cell line, MMT060562, were studied using fura‐2 fluorescence microscopy and the whole‐cell clamp technique. A sudden change of temperature from 37 to 45°C induced a transient increase in the fluorescence ratio permeability of the cell membrane and inward current. Deletion of extracellular calcium abolished the fluorescence ratio response to the rise in temperture. Ca i of some cells increased after hyperthermia treatment at 44–48°C for 20 min, but the average increase of Ca i was negligible. After hyperthermia treatment, spontaneous oscillation of Ca i , chemical responses to ATP and bradykinin and the mechanically‐induced spreading reponse diminished. However, the mechanically induced increase of Ca i within the stimulated cell remained even after hyperthermia treatment. Suppression of the ATP‐induced Ca i response recovered to about half the original level within 12 h. Blockage of protein synthesis with cycloheximide (100 μ M ) had no effect on the recovery. The D ‐myo‐inositol 1,4,5‐triphosphate (IP3)‐dependent increase of Ca i remained intact even after hyperthermia treatment. It is concluded that hyperthermia treatment increases both the permeability of the cell membrane and Ca i , but decreases the sensitivity of cells to ATP and bradykinin, presumably due to modification of the signal transduction mechanism.