TY - JOUR
T1 - Intracellular Ca2+ concentration change of T24 cell under irradiation in the presence of TiO2 ultrafine particles
AU - Sakai, Hideki
AU - Ito, Etsuro
AU - Cai, Ru Xiong
AU - Yoshioka, Toru
AU - Kubota, Yoshinobu
AU - Hashimoto, Kazuhito
AU - Fujishima, Akira
N1 - Funding Information:
The authors wish to express their appreciation to Dr. L. A. Nagahara for his useful discussions. The present work was partially supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, and Culture of Japan.
PY - 1994/11/11
Y1 - 1994/11/11
N2 - We respond that malignant cells are inactivated by photo-excited TiO2 particles (Cai, R.-X., et al. (1992) Cancer Res. 52, 2346-2348). In the present study, the process of cell death of a human bladder cell line T24 with the irradiated TiO2 was investigated by monitoring the time course change in intracellular calcium concentration ([Ca2+]i) under UV irradiation using calcium fluorescence indicator, fura-2. In the presence of photo-excited TiO2 particles (100 μg/ml), [Ca2+]i showed a rapid two-step increase, while in the absence of TiO2, it exhibited only a slight and monotonous increase or maintained a constant level. The rapid elevation of [Ca2+]i in the presence of photo-excited TiO2 particles was caused by the influx of extracellular Ca2+ through the plasma membrane and cell death occurred only after the second rapid elevation of [Ca2+]i. These results suggested that the cell membrane permeability to Ca2+ was promoted prior to cell death.
AB - We respond that malignant cells are inactivated by photo-excited TiO2 particles (Cai, R.-X., et al. (1992) Cancer Res. 52, 2346-2348). In the present study, the process of cell death of a human bladder cell line T24 with the irradiated TiO2 was investigated by monitoring the time course change in intracellular calcium concentration ([Ca2+]i) under UV irradiation using calcium fluorescence indicator, fura-2. In the presence of photo-excited TiO2 particles (100 μg/ml), [Ca2+]i showed a rapid two-step increase, while in the absence of TiO2, it exhibited only a slight and monotonous increase or maintained a constant level. The rapid elevation of [Ca2+]i in the presence of photo-excited TiO2 particles was caused by the influx of extracellular Ca2+ through the plasma membrane and cell death occurred only after the second rapid elevation of [Ca2+]i. These results suggested that the cell membrane permeability to Ca2+ was promoted prior to cell death.
KW - Fura-2
KW - Intracellular Ca concentration
KW - Photo-dynamic therapy
KW - T24 cell
KW - TiO
KW - UV light
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U2 - 10.1016/0304-4165(94)90049-3
DO - 10.1016/0304-4165(94)90049-3
M3 - Article
C2 - 7947940
AN - SCOPUS:0028037507
SN - 0006-3002
VL - 1201
SP - 259
EP - 265
JO - Biochimica et Biophysica Acta - General Subjects
JF - Biochimica et Biophysica Acta - General Subjects
IS - 2
ER -
