Proteasome inhibitors induced caspase-dependent apoptosis and accumulation of p21WAF1/Cip1 in human immature leukemic cells.
Proteasome inhibitors induced caspase-dependent apoptosis and accumulation of p21WAF1/Cip1 in human immature leukemic cells.
复制标题
蛋白酶体抑制剂诱导人未成熟白血病细胞中 caspase 依赖性细胞凋亡和 p21WAF1/Cip1 的积累。
DOI：
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发表时间：
2000
影响因子：
3.1
通讯作者：
K. Possinger
中科院分区：
文献类型：
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作者：
C. Naujokat;O. Sezer;H. Zinke;A. Leclere;S. Hauptmann;K. Possinger
26 S蛋白酶体是一种非溶酶体多催化蛋白酶复合物，通过ATP/泛素依赖性蛋白水解降解细胞内蛋白。对细胞周期控制至关重要的蛋白质的紧密有序的蛋白酶体降解意味着蛋白酶体在维持细胞增殖和细胞存活中的作用。在这项研究中，我们证明，细胞渗透性蛋白酶体抑制剂，lactacystin，苄氧羰基（Z）-亮氨酰-亮氨酰-亮氨酸，（ZLLLal; MG-132）和4-羟基-5-碘-3-硝基苯乙酰基-亮氨酰-亮氨酰-亮氨酸乙烯砜（NLVS）在p53缺陷型白血病细胞系CCRF-CEM中大量诱导凋亡，U937和K562以及从患有复发性急性白血病的成人个体获得的骨髓性和淋巴性白血病细胞中。由蛋白酶体抑制剂诱导的白血病细胞凋亡依赖于半胱天冬酶-3和相关半胱天冬酶家族蛋白酶的活化，因为半胱天冬酶-3抑制剂N-乙酰基-L-丙氨酰基-L-谷氨酰基-L-缬氨酰基-L-天冬氨酸醛（Ac-DEVD-cho）和更有效地，一般半胱天冬酶抑制剂N-苄氧羰基-L-缬氨酰基-L-丙氨酰基-L-天冬氨酸氟甲基酮（Z-VAD-fatty）能够阻断由lactacystin、ZLLLal或NLVS诱导的凋亡。由lactacystin或ZLLLal诱导的凋亡伴随着细胞周期停滞在G2/M期以及细胞周期蛋白依赖性激酶抑制剂p21 WAF 1/Cip和肿瘤抑制蛋白p53的积累和稳定。由于CCRF-CEM和U937细胞表达无功能突变型p53，而K562细胞缺乏p53表达，因此排除了p53在介导细胞凋亡或诱导p21 WAF 1/Cip 1中的作用。用lactacystin处理的人CD 34+祖细胞的活力和造血生长略微降低，而用ZLLLal或细胞抑制药物阿霉素和吉西他滨处理CD 34+细胞导致活力和造血生长显著降低。这些结果表明，蛋白酶体在维持人类白血病细胞的生存的基本作用，并可能定义细胞渗透性蛋白酶体抑制剂作为有效的抗白血病药物，表现出中度的造血毒性在体外。
The 26S proteasome is a non-lysosomal multicatalytic protease complex for degrading intracellular proteins by ATP/ubiquitin-dependent proteolysis. Tightly ordered proteasomal degradation of proteins critical for cell cycle control implies a role of the proteasome in maintaining cell proliferation and cell survival. In this study, we demonstrate that cell-permeable proteasome inhibitors, lactacystin, benzyloxycarbonyl(Z)-leucyl-leucyl-leucinal (ZLLLal; MG-132) and 4-hydroxy-5-iodo-3-nitrophenylacetyl-leucyl-leucyl-leucine vinyl sulfone (NLVS), induce apoptosis abundantly in p53-defective leukemic cell lines CCRF-CEM, U937 and K562 as well as in myelogenic and lymphatic leukemic cells obtained from adult individuals with relapsed acute leukemias. Leukemic cell apoptosis induced by the proteasome inhibitors was dependent on activation of caspase-3 and related caspase family proteases, because caspase-3 inhibitor N-acetyl-L-aspartyl-L-glutamyl-L-valyl-L-aspartal (Ac-DEVD-cho) and, more effectively, the general caspase-inhibitor N-benzyloxycarbonyl-L-valyl-L-alanyl-L-aspartate fluoromethylketone (Z-VAD-fmk) were capable of blocking apoptosis induced by lactacystin, ZLLLal or NLVS. Induction of apoptosis by lactacystin or ZLLLal was accompanied by cell cycle arrest at G2/M phase and by accumulation and stabilization of cyclin-dependent kinase inhibitor p21WAF1/Cip and tumor suppressor protein p53. A role of p53 in mediating apoptosis or induction of p21WAF1/Cip1 was ruled out since CCRF-CEM and U937 cells express non-functional mutant p53, and K562 cells lack expression of p53. Viability and hematopoietic outgrowth of human CD34+ progenitor cells treated with lactacystin were slightly reduced, whereas treatment of CD34 + cells with ZLLLal or the cytostatic drugs doxorubicin and gemcitabine resulted in markedly reduced viability and hematopoietic outgrowth. These results demonstrate a basic role of the proteasome in maintaining survival of human leukemic cells, and may define cell-permeable proteasome inhibitors as potently anti-leukemic agents which exhibit a moderate hematopoietic toxicity in vitro.