Modica-Napolitano J S, Koya K, Weisberg E, Brunelli B T, Li Y, Chen L B
Tufts University, Department of Biology, Medford, Massachusetts 02155, USA.
Cancer Res. 1996 Feb 1;56(3):544-50.
We investigated the mitochondrial toxicity of the lipophilic cation, MKT-077, and the role of mitochondria in selective malignant cell killing by this compound by examining the effect of MKT-077 on mitochondrial structure and function in treated cells and in isolated organelles. Results of this study demonstrate changes in mitochondrial ultrastructure that are induced by MKT-077 treatment in carcinoma cells but not in similarly treated normal epithelial cells. In addition, MKT-077 was found to inhibit respiratory activity in isolated intact mitochondria and electron transport activity in freeze-thawed mitochondrial membrane fragments in a dose-dependent manner. The concentration of MKT-077 necessary to obtain half-maximal inhibition of ADP-stimulated respiration was approximately 4-fold greater in mitochondria isolated from cells of the normal epithelial cell line, CV-1 (15 micrograms MKT-077/mg protein), as compared to the human colon carcinoma cell line, CX-1 (4 micrograms MKT-077/mg protein). Further, the data show a selective loss of mitochondrial DNA in CX-1 and CRL1420 cells (carcinoma) but not CV-1 cells (normal epithelial) treated with 3 microgram/ml MKT-077 for up to 3 days. Under the same conditions, nuclear DNA was unaffected in all three cell lines. The sensitivity of the cell lines tested to mitochondrial damage by MKT-077 correlates well with their sensitivity to cytotoxicity by MKT-077. These results demonstrate selective mitochondrial damage by MKT-077 at the cellular, biochemical, and molecular levels and suggest that selective effects on mitochondrial structure and function may provide a basis for the selective malignant cell killing exhibited by this compound.
我们通过检测MKT-077对经处理细胞及分离细胞器中线粒体结构和功能的影响，研究了亲脂性阳离子MKT-077的线粒体毒性以及线粒体在该化合物选择性杀伤恶性细胞中的作用。本研究结果表明，MKT-077处理可诱导癌细胞线粒体超微结构发生变化，但同样处理的正常上皮细胞则无此变化。此外，还发现MKT-077能剂量依赖性地抑制分离的完整线粒体的呼吸活性以及冻融线粒体膜片段的电子传递活性。与人类结肠癌细胞系CX-1（4微克MKT-077/毫克蛋白）相比，从正常上皮细胞系CV-1分离的线粒体中，获得ADP刺激呼吸半最大抑制所需的MKT-077浓度约高4倍（15微克MKT-077/毫克蛋白）。此外，数据显示，用3微克/毫升MKT-077处理长达3天的CX-1和CRL1420细胞（癌细胞）中线粒体DNA有选择性丢失，而CV-1细胞（正常上皮细胞）则没有。在相同条件下，所有三个细胞系的核DNA均未受影响。所测试细胞系对MKT-077所致线粒体损伤的敏感性与其对MKT-077细胞毒性的敏感性密切相关。这些结果在细胞、生化和分子水平上证明了MKT-077对线粒体的选择性损伤，并表明对线粒体结构和功能的选择性作用可能为该化合物表现出的选择性杀伤恶性细胞提供了基础。
