Puri R K, Ogata M, Leland P, Feldman G M, FitzGerald D, Pastan I
Division of Cytokine Biology, Food and Drug Administration, Bethesda, Maryland 20892.
Cancer Res. 1991 Jun 1;51(11):3011-7.
The presence of interleukin 4 receptor (IL-4R) on methylcholanthrene (MCA-106, MCA-102, and MC-38)- and viral DNA (G-2TS and 14-2TS)-induced murine sarcoma cells was demonstrated. MCA-106 tumor cells express about 500 to 1348 (median, 800) interleukin 4 (IL-4) binding sites/cell with a dissociation constant (Kd) of 115 +/- 26 pM (mean +/- SD, n = 4). By Northern blot analysis, tumor cells exhibited a single mRNA species of 3.9 kilobases. Other murine sarcoma (MCA-102), colon adenocarcinoma (MC-38), G-2TS, and 14-2TS tumor cells express low numbers of IL-4R. By immunoperoxidase staining, 81 to 92% of the cells from fresh MCA-106 tumors were positive for IL-4 receptors, while only 7 to 10% of tumor-infiltrating cells were Thy 1.2 and less than 1% Mac-1 positive. Using a chimeric protein composed of IL-4 and Pseudomonas exotoxin (IL-4-PE40), we observed that IL-4-PE40 was cytotoxic (determined by inhibition of protein synthesis by [3H]leucine uptake) to MCA-106 tumor cells in a dose-dependent manner. A nonchimeric protein (PE40) that cannot bind to the IL-4R did not inhibit protein synthesis in tumor cells. A chimeric mutant protein (IL4-PE40 asp553) that can bind to IL-4 receptors but does not have the capability to inhibit protein synthesis was not cytotoxic to tumor cells. These studies strongly suggest that IL-4R on murine MCA-106 sarcoma cells is internalized when occupied by IL-4 PE40. Furthermore, a neutralizing antibody (11B11) to IL-4 completely abolished the protein synthesis-inhibitory activity of IL-4-PE40. G-2TS tumor cells which expressed low numbers of IL-4 receptors were not vulnerable to cytotoxicity by IL-4-PE40. Taken together, these data suggest that IL-4 receptor may be a target for IL-4-toxin therapy.
已证实甲基胆蒽（MCA - 106、MCA - 102和MC - 38）及病毒DNA（G - 2TS和14 - 2TS）诱导的小鼠肉瘤细胞上存在白细胞介素4受体（IL - 4R）。MCA - 106肿瘤细胞表达约500至1348个（中位数为800个）白细胞介素4（IL - 4）结合位点/细胞，解离常数（Kd）为115±26 pM（平均值±标准差，n = 4）。通过Northern印迹分析，肿瘤细胞呈现出一种3.9千碱基的单一mRNA种类。其他小鼠肉瘤（MCA - 102）、结肠腺癌（MC - 38）、G - 2TS和14 - 2TS肿瘤细胞表达少量的IL - 4R。通过免疫过氧化物酶染色，新鲜MCA - 106肿瘤中81%至92%的细胞IL - 4受体呈阳性，而肿瘤浸润细胞中只有7%至10%的细胞Thy 1.2呈阳性，Mac - 1阳性细胞少于1%。使用由IL - 4和铜绿假单胞菌外毒素组成的嵌合蛋白（IL - 4 - PE40），我们观察到IL - 4 - PE40对MCA - 106肿瘤细胞具有细胞毒性（通过[³H]亮氨酸摄取抑制蛋白质合成来确定），且呈剂量依赖性。一种不能与IL - 4R结合的非嵌合蛋白（PE40）对肿瘤细胞中的蛋白质合成没有抑制作用。一种能与IL - 4受体结合但不具有抑制蛋白质合成能力的嵌合突变蛋白（IL4 - PE40 asp553）对肿瘤细胞没有细胞毒性。这些研究强烈表明，小鼠MCA - 106肉瘤细胞上的IL - 4R在被IL - 4 PE40占据时会被内化。此外，一种针对IL - 4的中和抗体（11B11）完全消除了IL - 4 - PE40的蛋白质合成抑制活性。表达少量IL - 4受体的G - 2TS肿瘤细胞对IL - 4 - PE40的细胞毒性不敏感。综上所述，这些数据表明IL - 4受体可能是IL - 4毒素疗法的一个靶点。
