Photoactivated fullerene C60 induces store-operated Ca2 entry and cytochrome c release in Jurkat cells

The values of endoplasmic reticulum Ca(2+)-pool and store-operated Ca2+ entry (SOCE) were estimated in rat thymocytes and Jurkat cells loaded with indo-1 and treated with thapsigargin. It was shown that the relative value of SOCE in thymocytes was substantially lower than in Jurkat cells. Significant increase of SOCE in Jurkat cells preincubated with 10(-5) M C60 and exposed to uv/visible light irradiation was detected at 1-3 h after exposure. At this time FCCP-induced Ca(2+)-release from mitochondria was shown to be reduced, while cytochrome c level into the cytoplasm of Jurkat cells, detected by Western blot analysis, to be increased. It is supposed that Ca2+ flux remodulation induced by photoexcited fullerene C60 in Jurkat cells might be involved in the initiation of signalling events leading to cell apoptosis.