Darzynkiewicz Z, Carter S P, Old L J
J Cell Physiol. 1987 Mar;130(3):328-35. doi: 10.1002/jcp.1041300304.
The tumor necrosis factor (TNF) exhibits a multitude of activities depending on the type of target cells. We characterized the cytostatic and cytotoxic effects of recombinant TNF, alone and in combination with actinomycin D (AMD), on the human leukemic cell line HL-60. Because HL-60 cells, when triggered to monocytic differentiation by phorbol esters, are known to produce and secrete TNF, their sensitivity to the factor could indicate an autocrine function of TNF in this cell system. Indeed, HL-60 cells were affected by TNF; their doubling time was increased by about 50% and progression through the cell cycle was perturbed. Initially, (up to 8 h) TNF induced a temporary arrest in G2 while later (24-48 h) it delayed progression through the G1 phase. Also, a transient increase in RNA content peaking at 6-8 h was apparent. The cytotoxicity of TNF alone was low. Thus, TNF may be involved in the regulation of the cell cycle of HL-60 cells during early stages of their differentiation. The cytotoxicity of TNF was markedly potentiated in the presence of AMD; the effect was AMD but not TNF concentration-dependent. Whereas at 20 and 50 ng/ml of AMD alone nonviable cells did not exceed 20% during the first 24 h of treatment, their proportion increased to 80 and 90%, respectively, in the presence of TNF. The most sensitive were cells in the S phase of the cell cycle. The observed synergistic effect of TNF and AMD does not appear to be caused by the action of TNF increasing the permeability of the cell membrane to AMD. The results indicate that HL-60 cells, ordinarily resistant to the cytotoxic action of TNF, can be rendered sensitive by treatment with AMD. This implies that a combination of TNF and AMD may be considered in oncology for treatment of tumors otherwise nonresponding to TNF alone.
肿瘤坏死因子（TNF）根据靶细胞类型表现出多种活性。我们研究了重组TNF单独及与放线菌素D（AMD）联合使用对人白血病细胞系HL - 60的细胞生长抑制和细胞毒性作用。由于已知HL - 60细胞在佛波酯诱导下向单核细胞分化时会产生并分泌TNF，它们对该因子的敏感性可能表明TNF在这个细胞系统中具有自分泌功能。事实上，HL - 60细胞受到TNF的影响；其倍增时间增加了约50%，细胞周期进程受到干扰。最初（长达8小时），TNF诱导细胞在G2期暂时停滞，而后来（24 - 48小时）它延迟了细胞通过G1期的进程。此外，在6 - 8小时达到峰值的RNA含量出现短暂增加。单独使用TNF时细胞毒性较低。因此，TNF可能在HL - 60细胞分化的早期阶段参与细胞周期的调控。在AMD存在的情况下，TNF的细胞毒性显著增强；这种作用取决于AMD的浓度而非TNF的浓度。单独使用20和50 ng/ml的AMD时，在处理的前24小时内非存活细胞不超过20%，而在TNF存在的情况下，其比例分别增加到80%和90%。细胞周期S期的细胞最为敏感。观察到的TNF和AMD的协同作用似乎不是由TNF增加细胞膜对AMD的通透性所导致的。结果表明，通常对TNF细胞毒性作用具有抗性的HL - 60细胞，经AMD处理后可变得敏感。这意味着在肿瘤学中，对于那些单独使用TNF无反应的肿瘤，可考虑联合使用TNF和AMD进行治疗。
