LAK cell mediated apoptosis of human bladder cancer cells involves a pH-dependent endonuclease system in the cancer cell: possible mechanism of BCG therapy.
LAK cell mediated apoptosis of human bladder cancer cells involves a pH-dependent endonuclease system in the cancer cell: possible mechanism of BCG therapy.
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DOI：
10.1016/s0022-5347(01)67292-6
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发表时间：
1995-07
期刊：
影响因子：
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通讯作者：
M. M. Shemtov-M.;D. L. Cheng;L. Kong;W. Shu;M. Sassaroli;M. Droller;B. Liu
中科院分区：
文献类型：
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作者：
M. M. Shemtov-M.;D. L. Cheng;L. Kong;W. Shu;M. Sassaroli;M. Droller;B. Liu
卡介苗膀胱灌注是治疗浅表性膀胱癌的有效方法。然而，其机制仅得到部分阐明。本实验研究了LAK细胞对人膀胱癌细胞的杀伤作用是通过凋亡（程序性细胞死亡）还是坏死发生的，荧光显微镜下观察到LAK细胞作用下T24细胞发生凋亡相关的形态学改变。此外，对从细胞毒性测定中分离的DNA的分析证实，LAK细胞诱导的T24细胞的死亡通过凋亡发生。用抗纤连蛋白抗体预处理LAK细胞，可明显抑制LAK细胞对T24细胞的杀伤作用。细胞毒性百分比从50%降低到13%（p = 0.001），琼脂糖凝胶电泳上观察到的凋亡模式显著减少。从人膀胱癌T24细胞中分离的核酸内切酶表明，这些细胞表达pH依赖性的核酸内切酶，而不是CA sup ++ /Mg sup ++依赖性的核酸内切酶。仅在含有来自T24细胞的核酸内切酶的pH 4至pH 5.6缓冲液中观察到靶DNA的显著降解，而在含有来自T24细胞的核酸内切酶的pH 6至pH 8缓冲液中未观察到靶DNA的显著降解。在各种pH缓冲液中存在或不存在Ca sup ++ /Mg sup ++不改变内切核酸酶活性。我们证明，用质子离子载体尼日利亚菌素改变细胞内pH值至5.6或更低，可以诱导T24细胞死亡。我们的结论是，LAK细胞诱导T24细胞凋亡，这一过程涉及存在于细胞表面的纤连蛋白分子。LAK细胞膜。此外，T24细胞DNA的切割可以通过存在于这些细胞中的pH依赖性核酸内切酶发生。我们推测，在体内，由BCG激活的CD 4 sup +细胞产生的IL-2激活的LAK细胞可诱导膀胱癌细胞发生凋亡。这可能部分解释BCG达到治疗效果的机制。
Intravesical bacillus Calmette-Guerin (BCG) is an effective treatment for superficial bladder cancer. However, its mechanism has been only partially elucidated. We studied whether LAK cell killing of human bladder cancer cells occurs via apoptosis (programmed cell death) or necrosis.Fluorescent dye labeled T24 cells were observed to undergo morphologic changes associated with apoptosis in the presence of LAK cells when analyzed under a fluorescence microscope. Furthermore, analysis of the DNA isolated from the cytotoxic assay confirmed that the LAK cell induced death of the T24 cells occurred via apoptosis. By pretreating the LAK cells with antifibronectin antibodies, we were able to significantly inhibit the LAK cell killing of the T24 cells. The percentage of cytotoxicity was reduced from 50 percent to 13 percent (p = 0.001), and the apoptotic pattern seen on agarose gel electrophoresis was significantly diminished. There was no significant change in the viability of the LAK cells following treatment with the antibodies.Endonuclease isolation from human bladder cancer T24 cells demonstrated that these cells express a pH-dependent and not a CA sup ++ /Mg sup ++ dependent endonuclease. Significant degradation of a target DNA was observed only in pH 4 to pH 5.6 buffers containing endonuclease from T24 cells and not in pH 6 to pH 8 buffers containing endonuclease from T24 cells. The presence or absence of Ca sup ++ /Mg sup ++ in the various pH buffers did not alter the endonuclease activity.Finally, we demonstrated that death of T24 cells can be induced by altering the intracellular pH of the cells to 5.6 or lower with the proton ionophore nigericin.We conclude that LAK cells induce T24 cells to undergo apoptosis and that this process involves the fibronectin molecule present on the LAK cell membrane. Furthermore, the cleavage of the T24 cellular DNA may occur via a pH-dependent endonuclease present in these cells. We postulate that, in vivo, LAK cells activated by IL-2 produced by BCG activated CD4 sup + cells may induce bladder cancer cells to undergo apoptosis. This may partially explain the mechanism whereby BCG achieves its therapeutic effect.