Kitamura Yoshihisa, Miyamura Atsushi, Takata Kazuyuki, Inden Masatoshi, Tsuchiya Daiju, Nakamura Kumi, Taniguchi Takashi
Department of Neurobiology, Kyoto Pharmaceutical University, Kyoto, Japan.
J Pharmacol Sci. 2003 Jul;92(3):228-36. doi: 10.1254/jphs.92.228.
Recently, it has been shown that endoplasmic reticulum (ER) stress causes apoptosis. However, the mechanism of the ER stress-dependent pathway is not fully understood. In human neuroblastoma SH-SY5Y cells, we detected a caspase-12-like protein that has a molecular mass (approximately 60 kDa) similar to that of mouse caspase-12. Thapsigargin, an inhibitor of ER-associated Ca(2+)-ATPase, induced the degradation of caspase-12-like protein. In addition, the degradation of caspases-9 and -3, cleavage of poly(ADP-ribose) polymerase, DNA fragmentation, and cell death were also observed. Pretreatment with phorbol-12-myristate-13-acetate, which induces the expression of antiapoptotic Bcl-2, inhibited thapsigargin-induced degradation of caspases-9 and -3, but not caspase-12-like protein degradation. A caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp(OCH(3))-CH(2)F, inhibited the degradation of caspase-12-like protein, but not that of caspases-9 and -3. These results suggest that thapsigargin may induce the activation of both ER- and mitochondria-dependent pathways in human SH-SY5Y cells.
最近的研究表明，内质网（ER）应激可导致细胞凋亡。然而，内质网应激依赖途径的机制尚未完全明确。在人神经母细胞瘤SH-SY5Y细胞中，我们检测到一种分子量（约60 kDa）与小鼠caspase-12相似的类caspase-12蛋白。内质网相关Ca(2+)-ATP酶抑制剂毒胡萝卜素可诱导类caspase-12蛋白降解。此外，还观察到caspase-9和caspase-3的降解、聚（ADP-核糖）聚合酶的切割、DNA片段化以及细胞死亡。用佛波酯-12-肉豆蔻酸酯-13-乙酸酯预处理可诱导抗凋亡Bcl-2的表达，抑制毒胡萝卜素诱导的caspase-9和caspase-3降解，但不抑制类caspase-12蛋白降解。一种caspase抑制剂苄氧羰基-Val-Ala-Asp(OCH(3))-CH(2)F可抑制类caspase-12蛋白降解，但不抑制caspase-9和caspase-3降解。这些结果表明，毒胡萝卜素可能诱导人SH-SY5Y细胞中内质网和线粒体依赖途径的激活。
