Serum deprivation and protein synthesis inhibition induce two different apoptotic processes in N18 neuroblastoma cells
Serum deprivation and protein synthesis inhibition induce two different apoptotic processes in N18 neuroblastoma cells
复制标题
DOI：
10.1006/excr.1997.3852
复制
发表时间：
1998-02-01
影响因子：
3.7
通讯作者：
Comella, JX
中科院分区：
文献类型：
--
作者：
Boix, J;Fibla, J;Comella, JX
N18是小鼠神经母细胞瘤细胞，在血清剥夺或放线菌酮（CHX）抑制蛋白质合成时发生细胞死亡，在这两种情况下，都发现了典型的凋亡的超微结构形态和核小体间DNA断裂模式，然而，电子显微镜显示CHX处理的细胞胞质中有丰富的脂质囊泡，而在血清剥夺的细胞中没有发现。此外，当这两种类型的凋亡细胞进行比较，通过流式细胞术和染色质染色碘化丙啶，前者表现出一贯低于后者的荧光。因此，在N18细胞中，两种凋亡过程似乎在结构水平上不同。在功能水平上，我们发现，细胞凋亡被阻断的蛋白酶抑制剂TLCK在CHX处理，但不是在血清剥夺细胞。另一方面，我们产生了过表达Bcl-2蛋白的N18克隆。48小时后，我们发现相同水平的Bcl-2蛋白能够阻断血清剥夺的细胞中的细胞凋亡，但不能阻断CHX处理的细胞中的细胞凋亡。总之，导致细胞凋亡的两种不同的生物化学途径似乎共存于N18神经母细胞瘤细胞中，（C）1998 Academic Press。
N18 are murine neuroblastoma cells that underwent cell death upon serum deprivation or inhibition of protein synthesis by means of cycloheximide (CHX), In both cases, an ultrastructural morphology and an internucleosomal pattern of DNA fragmentation typical of apoptosis were found. However, electron microscopy revealed abundant lipid vesicles in the cytoplasm of CHX-treated cells that were not found in their serum-deprived counterparts. In addition, when both types of apoptotic cells were compared by means of flow cytometry and chromatin staining with propidium iodide, the former showed consistently less fluorescence than the latter. Therefore, in N18 cells, both apoptotic processes seemed to differ at a structural level. At a functional level, we found that apoptosis was blocked by the protease inhibitor TLCK in CHX-treated but not in serum-deprived cells. On the other hand, we generated N18 clones that overexpressed Bcl-2 protein. After a period of 48 h we found that identical levels of Bcl-2 protein were able to block apoptosis in serum-deprived but not in CHX-treated cells, In conclusion, two different biochemical pathways leading to apoptosis seem to coexist in N18 neuroblastoma cells, (C) 1998 Academic Press.