Tobacco Helps Cancer Cells Evade Destruction

　

烟草帮助癌细胞逃脱毁灭

New research suggests that tobacco not only promotes cancer development, but also helps early cancer cells evade detection by the immune system, which might otherwise mop up harmful cells before they reproduce and spread.新的研究表明，烟草不仅会促进癌症的发展，而且还能帮助早期的癌细胞逃避人的免疫系统的检测，而这种检测有可能在癌细胞繁殖和扩散之前就将其消灭。Dr. Jane A. McCutcheon and her colleagues at New York University in New York City discovered that cells exposed to tobacco have fewer substances on their surfaces used to signal whether or not the cell is dangerous and should be destroyed by the immune system. As such, McCutcheon suggested in an interview with Reuters Health, cells with fewer of these warning devices, if they become cancerous, would be more likely to evade detection by the immune system, grow and spread throughout the body.纽约市纽约大学的Jane A. McCutcheon博士和她的同事发现，细胞接触烟草后，其表面的一些物质减少了，而正是这些物质可发出细胞是否有危险以及免疫系统是否应该将其消灭的讯号。鉴于此，McCutcheon在接受路透社健康通讯的一次采访中说，由于细胞报警能力的降低，一旦细胞发生癌变，它们就很有可能逃避人体免疫系统的监测而繁殖起来，并扩散到全身。The cellular warning devices are known as HLA class 1 molecules, which are usually unique to each person. These molecules sit on the surface of cells and present a protein to the outside environment. If this protein is derived from harmless substances inside the cell, immune system components known as killer T cells will bypass the cell, considering it to pose no threat to the body. However, if the protein inside a class 1 molecule was made as a result of a cancer inside the cell, or comes from a virus, the T cells hone in on the cell and destroy it.这种细胞报警构造叫做HLA 1 组分子，在通常情况下，每一个人的HLA 1 组分子都是独特的。这些分子位于细胞的表面，向周围环境发出一种蛋白质。如果该蛋白质来自于细胞中无害的物质，免疫系统中一种被称为T细胞杀手会认为它们对人体不构成威胁而将其放行。然而，如果HLA 1 组分子内的蛋白质是由细胞癌变所产生的，或来自于病毒，T细胞就会围剿和消灭它们。In a recent issue of the Journal of Immunology, McCutcheon and her colleagues presented the results of experiments in which they found that cells exposed to tobacco showed fewer HLA class 1 molecules. Further experiments revealed that cells exposed to tobacco show lower levels of a particular protein that forms a link in the chain that assembles HLA class 1 molecules inside the cell. Reductions in this protein, known as TAP1, likely lead to lower amounts of HLA class 1 on the cell surface, the authors suggest.在最近一期《免疫学》杂志上，McCutcheon和她的同事公布了实验结果，该结果表明接触过烟草的细胞含有较少的HLA 1 组分子。进一步的实验结果显示，接触过烟草的细胞内有一种特殊蛋白质的含量降低了，该蛋白质在细胞内可形成"流水线"来组装HLA 1 组分子。McCutcheon还指出，一种被称为TAP1蛋白质的减少很可能导致了细胞表面HLA 1 组分子的含量降低。In an interview with Reuters Health, McCutcheon cautioned that these changes do not cause cancer, but simply allow the cancer to thrive in the body once it appears.在接受路透社健康通讯的采访时，McCutcheon告诫人们，这些变化本身不会造成癌症，但是可以在癌症发生时，允许其在体内肆无忌惮。"The class 1 is gone before the cell becomes cancerous," she said. "If those cells become cancerous, there isn't enough class 1 for T cells to kill them."她说："在细胞癌变前，HLA 1 组分子已减少。如果这些细胞发生癌变，就会造成HLA 1 组分子含量不足，致使T细胞不能消灭癌细胞。"McCutcheon noted that tobacco has a lot of ingredients, and she and her colleagues remain unsure about which particular ingredients might interfere with the cells' production of HLA class 1. In the meantime, she noted that all tobacco-containing substances-not just those that people smoke-would likely have the same effect. "If you just sucked on a cigarette it could do this to you," she said.McCutcheon注意到烟草含有很多成份，而她和她的同事仍然不能确定究竟是哪些烟草成份干扰了细胞产生HLA 1 组分子。与此同时，她还注意到，不仅是人们所抽的烟草，所有含有烟草的物质都有可能具有同样的效果。她说："只要你抽烟，就可能有此危险。"In the future, McCutcheon predicted, it may be possible to design a product that smokers could suck or somehow ingest that could help restore healthy HLA class 1 levels. Tobacco still triggers cancer, she said, but boosting the body's ability to destroy early cancers might help smokers fight off more cases of the disease than they would otherwise. However, the bottom line remains the same, McCutcheon noted: "Cigarettes are bad."McCutcheon预测，将来有可能设计出一种产品来帮助吸烟者恢复到健康的HLA 1 组分子含量。她说，烟草仍然可引发癌症，但加强人体消灭早期癌细胞的能力，可以使吸烟者比以前要提高一些抗癌能力。然而，结果仍是一样的，McCutcheon强调："香烟对健康有害"。