Furuke K, Sasada T, Ueda-Taniguchi Y, Yamauchi A, Inamoto T, Yamaoka Y, Masutani H, Yodoi J
Department of Biological Responses, Institute for Virus Research, College of Medical Technology, Kyoto University, Japan.
Cancer Res. 1997 Nov 1;57(21):4916-23.
We have shown that cell cycle progression of human T-cell leukemia virus type I (HTLV-I)-transformed T-cell lines was inhibited by 13-cis-retinoic acid (13cRA). In the present study, we report that 13cRA inhibited proliferation and induced cell death of peripheral blood mononuclear cells obtained from four patients with acute adult T-cell leukemia but not of mitogen- or interleukin 2-activated peripheral blood mononuclear cells from HTLV-I-negative healthy donors. Because HTLV-I-infected lymphocytes are susceptible to oxidative stress, we examined the role of the intracellular redox state in 13cRA-induced cell death using a HTLV-I-positive T-cell line, ATL2, as a model. 13cRA induced apoptosis in ATL2 cells within 48 h in a dose-dependent manner. The ability of 13cRA to induce apoptosis was more potent than that of all-trans-retinoic acid. Apoptosis induction by 13cRA was significantly enhanced by buthionine sulfoximine (BSO), which decreased the levels of intracellular reduced glutathione, although 13cRA by itself did not alter them, suggesting that intracellular reduced glutathione may modulate 13cRA-induced apoptosis. In addition, flow cytometric analysis revealed that 13cRA increased intracellular peroxides in 24 h and that the addition of BSO further enhanced them. Although N-acetylcysteine had only a marginal effect, pretreatment with catalase markedly inhibited 13cRA-induced apoptosis. These results suggest that peroxide generation, ie., oxidative stress, may play a crucial role in the induction of apoptosis by 13cRA and further demonstrate that combined treatment with 13cRA and BSO induces apoptosis of HTLV-I-positive lymphocytes even more potently.
我们已经证明，13-顺式维甲酸（13cRA）可抑制人I型嗜T细胞白血病病毒（HTLV-I）转化的T细胞系的细胞周期进程。在本研究中，我们报告13cRA抑制了4例急性成人T细胞白血病患者外周血单个核细胞的增殖并诱导其死亡，但对来自HTLV-I阴性健康供体的丝裂原或白细胞介素2激活的外周血单个核细胞没有此作用。由于HTLV-I感染的淋巴细胞易受氧化应激影响，我们以HTLV-I阳性T细胞系ATL2为模型，研究了细胞内氧化还原状态在13cRA诱导的细胞死亡中的作用。13cRA在48小时内以剂量依赖的方式诱导ATL2细胞凋亡。13cRA诱导凋亡的能力比全反式维甲酸更强。丁硫氨酸亚砜胺（BSO）可降低细胞内还原型谷胱甘肽水平，显著增强13cRA诱导的凋亡，尽管13cRA本身不会改变细胞内还原型谷胱甘肽水平，这表明细胞内还原型谷胱甘肽可能调节13cRA诱导的凋亡。此外，流式细胞术分析显示，13cRA在24小时内增加了细胞内过氧化物，添加BSO可进一步增强过氧化物水平。尽管N-乙酰半胱氨酸只有轻微作用，但过氧化氢酶预处理可显著抑制13cRA诱导的凋亡。这些结果表明，过氧化物生成，即氧化应激，可能在13cRA诱导的凋亡中起关键作用，并进一步证明13cRA与BSO联合治疗能更有效地诱导HTLV-I阳性淋巴细胞凋亡。
