Asher A L, Mulé J J, Kasid A, Restifo N P, Salo J C, Reichert C M, Jaffe G, Fendly B, Kriegler M, Rosenberg S A
Division of Cancer Treatment, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
J Immunol. 1991 May 1;146(9):3227-34.
Studies of the anti-tumor activity of TNF-alpha in vivo have been hampered by the need to administer systemically toxic doses of the cytokine to obtain a curative response. To facilitate studies of the effect of high local concentrations of TNF-alpha on tumor growth and host immunity, a newly induced murine sarcoma was transduced with the gene for human TNF-alpha and the biologic characteristics of these cells were examined. We identified high and low TNF-producing tumor clones which exhibited stable TNF secretion over time. Significant amounts of membrane associated TNF were found in a high-TNF producing clone as well. No difference in the in vitro growth rates between TNF-producing and nonproducing cell lines was observed. In contrast, in vivo studies demonstrate that although unmodified parental tumor cells grew progressively when implanted s.c. in animals, tumor cells transduced with the TNF gene were found to regress in a significant number of animals after an initial phase of growth. This effect correlated with the amount of TNF produced and could be blocked with a specific anti-TNF antibody. Regressions of TNF-producing cells occurred in the absence of any demonstrable toxicity in the animals bearing these tumors. TNF-producing tumor cells could function in a paracrine fashion by inhibiting the growth of unmodified, parental tumor cells implanted at the same site. The ability of tumor cells to regress was abrogated by in vivo depletion of CD4+ or CD8+ T cell subsets and animals that had experienced regression of TNF-producing tumors rejected subsequent challenges of parental tumor. Our studies thus show that tumor cells elaborating high local concentrations of TNF regress in the absence of toxicity in the host and that this process requires the existence of intact host immunity. Studies of the lymphocytes infiltrating the gene modified tumors and attempts to use TNF gene modified tumor infiltrating lymphocytes to deliver high local concentrations of TNF to the tumor site without inducing systemic toxicity are underway.
肿瘤坏死因子-α（TNF-α）体内抗肿瘤活性的研究一直受到限制，因为需要全身给予毒性剂量的细胞因子才能获得治愈反应。为了便于研究高局部浓度的TNF-α对肿瘤生长和宿主免疫的影响，将新诱导的小鼠肉瘤转导人TNF-α基因，并检测这些细胞的生物学特性。我们鉴定出高TNF分泌和低TNF分泌的肿瘤克隆，它们随时间表现出稳定的TNF分泌。在一个高TNF分泌克隆中还发现了大量与膜相关的TNF。未观察到TNF分泌细胞系和非分泌细胞系在体外生长速率上的差异。相反，体内研究表明，虽然未修饰的亲本肿瘤细胞皮下植入动物后会逐渐生长，但转导TNF基因的肿瘤细胞在生长初始阶段后，在大量动物中出现消退。这种效应与TNF的产生量相关，并且可以被特异性抗TNF抗体阻断。产生TNF的细胞发生消退时，携带这些肿瘤的动物没有任何明显的毒性。产生TNF的肿瘤细胞可以通过旁分泌方式抑制同一部位植入的未修饰亲本肿瘤细胞的生长。体内清除CD4 +或CD8 + T细胞亚群可消除肿瘤细胞消退的能力，并且经历过产生TNF肿瘤消退的动物会排斥随后亲本肿瘤的攻击。因此，我们的研究表明，产生高局部浓度TNF的肿瘤细胞在宿主无毒性的情况下发生消退，并且这个过程需要完整的宿主免疫存在。目前正在研究浸润基因修饰肿瘤的淋巴细胞，并尝试使用TNF基因修饰的肿瘤浸润淋巴细胞将高局部浓度的TNF递送至肿瘤部位而不引起全身毒性。
