EFFECTS OF VINBLASTINE, LEUCINE, AND HISTIDINE, AND 3-METHYLADENINE ON AUTOPHAGY IN EHRLICH ASCITES-CELLS
EFFECTS OF VINBLASTINE, LEUCINE, AND HISTIDINE, AND 3-METHYLADENINE ON AUTOPHAGY IN EHRLICH ASCITES-CELLS
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DOI：
10.1016/0014-4800(90)90061-h
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发表时间：
1990-02-01
影响因子：
3.6
通讯作者：
REUNANEN, H
中科院分区：
文献类型：
--
作者：
PUNNONEN, EL;REUNANEN, H
微管抑制剂长春碱导致许多细胞类型中自噬空泡的积累。在肝细胞中，许多积聚的空泡是新生的，这表明长春碱通过抑制含水解酶的溶酶体与早期自噬空泡融合而发挥作用。然而，我们以前的结果表明，在埃利希腹水细胞，长春碱的原因积累，主要是老年自噬空泡（AV）。本研究旨在进一步表征长春碱在这些细胞中的作用模式。通过电子显微镜形态测定法定量长春碱累积的AV。此外，研究了自噬分离抑制剂（亮氨酸、组氨酸和3-甲基腺嘌呤）对长春碱诱导的自噬空泡积累的影响。使用[14 C]缬氨酸测量蛋白质降解。长春碱引起晚期自噬空泡的积累，但不增加蛋白质降解速率。早期液泡的体积密度保持在对照水平。氨基酸延缓，但没有阻止自噬泡的积累，而3-甲基腺嘌呤几乎完全阻止了积累。结果表明，埃利希腹水细胞长春碱通过抑制晚期自噬空泡成熟为残留体和刺激新的自噬空泡的形成而起作用。然而，3-甲基腺嘌呤几乎完全阻止长春碱存在下新的自噬空泡的形成。总之，在埃利希腹水细胞中，长春碱不能阻止水解酶进入自噬空泡。这使人对微管在溶酶体酶转运到自噬泡中的重要性产生了疑问。
The microtubule inhibitor vinblastine causes accumulation of autophagic vacuoles in many cell types. In hepatocytes, many of the accumulated vacuoles are nascent, which has been interpreted to suggest that vinblastine acts by inhibiting the fusion of hydrolase-containing lysosomes with early autophagic vacuoles. However, our previous results suggested that, in Ehrlich ascites cells, vinblastine causes accumulation and mainly of older autophagic vacuoles (AVs). This study was undertaken to further characterize the mode of action of vinblastine in these cells. The vinblastine-accumulated AVs were quantified by electron-microscopic morphometry. In addition, the effects of inhibitors of autophagic segregation (leucine, histidine, and 3-methyladenine) on the vinblastine-induced accumulation of autophagic vacuoles were studied. Protein degradation was measured using [14C]valine. Vinblastine caused accumulation of advanced autophagic vacuoles but did not increase the rate of protein degradation. The volume density of early vacuoles remained at the control level. The amino acids retarded but did not prevent the accumulation of autophagic vacuoles, whereas 3-methyladenine almost completely prevented the accumulation. The results suggest that Ehrlich ascites cells vinblastine acts by inhibiting the maturation of advanced autophagic vacuoles into residual bodies and by stimulating the formation of new autophagic vacuoles. However, 3-methyladenine almost completely prevents the formation of new autophagic vacuoles in the presence of vinblastine. In conclusion, in Ehrlich ascites cells, vinblastine does not prevent the entry of hydrolases into autophagic vacuoles. This calls into question the importance of microtubules in the transport of lysosomal enzymes into autophagic vacuoles.