Morphological Study on the Mechanism of Tumor-selective Cytocidal Action of Tumor Necrosis Factor

摘要

Using light microscopy and electron microscopy, we observed the morphological changes inheuman hepatocellular carcinoma cell line (SMMC-7721) treated with tumor necrosis tumor necrosis factor (TNF)and the cytocidal effect of TNF on the heterotransplanted human hepatocellular carcinoma. It wasfound that the changes of the injury occurred earlier in the cell membranes than in the nuclei duringthe course of TNF killing of SMMC-7721 cells and there were similar lesions around the necroticarea in the heterotransplanted human hepatocellular carcinoma in the nude mice as compared withthose produced in SMMC-7721 cells. In addition, the determination of the DNA content in TNF-treated SMMC-7721 cells and controls revealed no significant difference between them. On the basisof these results and Darzynkiewicz’s proposals, it is suggested that TNF exerts its tumor-selectivekilling effect by binding to a specific to a specific plasma membrane receptor to disturb synthesis or assembly ofcell membrane components, thus causing the plasma membrane injury and finally cell lysis.