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凋亡（apoptosis）,也即程序性细胞死亡,是由基因控制的细胞的自我消亡。细胞凋亡的基本过程是细胞表面分子接到诱导因子刺激并将信号传入细胞内部,触发细胞内部的死亡程序,导致细胞死亡。此过程发生紊乱将导致发育异常和肿瘤发生。同样,在肿瘤中也存在凋亡,癌细胞中仍然保持着这种自杀程序。不过是存活细胞的数量和存活时间超过了死亡细胞。本文将就近年来有关肺癌与细胞凋亡的关系予以综述。1 细胞凋亡的特征 凋亡的概念由Wyllie在1972年首先提出,apoptosis的本意为秋天的树叶从树上凋落,在此形容凋亡细胞形成凋亡小体从细胞上脱落,继而被吞噬细胞吞噬。细胞凋亡的一个最直观的指标就是DNA的片断化,DNA在核小体之间被切断,成为180bp及其倍数大小的一系列DNA,经核酸电泳后就能得到一个DNA阶梯。目前了解较多的可介导DNA片段化的酶有三种:NUC-18、DNase Ⅰ和DNase Ⅱ。而内切酶活性依赖于钙和镁离子,并受到锌离子的抑制。 Darzynkiewicz等用流式细胞仪观察到细胞凋亡具有以下特征:1.由于细胞核酸内切酶激活,使得DNA特异性荧光染色减少;2.细胞浆膜完整;3.线粒体仍有跨膜电位;4.保留了ATP依赖的溶酶体质子泵;5.蛋白含量明显减少,原因是内源性内切酶被激活;6.凋亡发生于G_0期胸腺细胞;7.前向散射减少
Apoptosis, or programmed cell death, is the death of a gene-controlled cell. The basic process of apoptosis is that cell surface molecules are stimulated by an inducing factor and the signal is introduced into the interior of the cell, triggering a death process inside the cell, leading to cell death. Disorders in this process will lead to abnormal development and tumorigenesis. Similarly, there is apoptosis in tumors, and this suicide procedure is still maintained in cancer cells. However, the number of surviving cells and the survival time exceed that of dead cells. This article will review the relationship between lung cancer and apoptosis in recent years. 1 Characteristics of Apoptosis The concept of apoptosis was first proposed by Wyllie in 1972. The idea of apoptosis is the fall of leaves from the tree. Here it is described that apoptotic cells form apoptotic bodies and then fall off from the cells, followed by phagocytes. Devouring. One of the most intuitive indicators of apoptosis is the fragmentation of DNA. DNA is cleaved between nucleosomes and becomes a series of DNA with a size of 180 bp and multiples. After DNA electrophoresis, a DNA ladder can be obtained. At present, there are three known enzymes that can mediate DNA fragmentation: NUC-18, DNase I, and DNase II. Endonuclease activity is dependent on calcium and magnesium ions and is inhibited by zinc ions. Darzynkiewicz and other flow cytometry observation of apoptosis has the following characteristics: 1. As a result of cell endonuclease activation, making the specific fluorescence staining decreased; 2. The plasma membrane integrity; 3. Mitochondria still have transmembrane potential; 4. The ATP-dependent lysosomal proton pump is retained; 5. The protein content is significantly reduced because the endogenous endonuclease is activated; 6. The apoptosis occurs in the G_0 thymocytes; 7. The forward scattering decreases