Obiri N I, Hillman G G, Haas G P, Sud S, Puri R K
Division of Cytokine Biology, Food and Drug Administration, Bethesda, Maryland 20892.
J Clin Invest. 1993 Jan;91(1):88-93. doi: 10.1172/JCI116205.
Previously, Puri et al. (Puri, R. K., M. Ogata, P. Leland, G. M. Feldman, D. Fitzgerald, and I. Pastan. 1991. Cancer Res. 51:3011-3017) have demonstrated that murine sarcoma and colon adenocarcinoma cells express high affinity interleukin-4 receptors (IL-4R) which are internalized after binding to a chimeric ligand consisting of IL-4 and Pseudomonas exotoxin. In the present study, we have tested primary cultures of human renal cell carcinoma (RCC) cells, generated from tumor specimens obtained after nephrectomy, for the expression of IL-4R and their modulation by IL-4. By using iodinated IL-4 in a receptor binding assay, we observed that renal cell carcinoma cells expressed a single class of high affinity IL-4R ranging from 1,425 +/- 207 (mean +/- SEM) to 3,831 +/- 299 (mean +/- SEM) IL-4R molecules/cell with a Kd ranging from 112 +/- 11 pM to 283 +/- 71 pM. Northern blot analysis for IL-4R gene expression, performed with a cDNA probe to IL-4R, revealed that all RCC cells exhibited a single mRNA species of 4 kb. IL-4 downregulated the surface expression of IL-4R on one RCC tumor cell line. The function of IL-4R expression on RCC tumor cells was further determined by investigating the effect of IL-4 on tumor cell growth in vitro and comparing it with IL-4 effect on growth of normal fibroblast and endothelial cell lines. Tumor cell growth, as measured by [3H]thymidine incorporation, was inhibited by IL-4 from 20 to 68% in a dose-dependent manner. A neutralizing antibody to human IL-4 was able to reverse the growth inhibitory effect of IL-4. Normal human fibroblast and endothelial cell lines also expressed high affinity IL-4R, however, IL-4 did not inhibit their growth in vitro. In fact, IL-4 caused modest stimulation of their growth. Taken together, our findings can help develop strategies for the treatment of RCC in which IL-4R may be used as a target for IL-4 itself, for IL-4 toxin therapy or, alternatively, in gene therapy.
此前，普里等人（普里，R.K.，M.绪方，P.利兰，G.M.费尔德曼，D.菲茨杰拉德，和I.帕斯坦。1991年。《癌症研究》51:3011 - 3017）已证明，鼠肉瘤细胞和结肠腺癌细胞表达高亲和力白细胞介素-4受体（IL-4R），该受体在与由白细胞介素-4和绿脓杆菌外毒素组成的嵌合配体结合后会被内化。在本研究中，我们检测了从肾切除术后获得的肿瘤标本中培养的人肾细胞癌（RCC）原代细胞，以检测IL-4R的表达及其受IL-4的调节情况。通过在受体结合试验中使用碘化IL-4，我们观察到肾细胞癌细胞表达一类单一的高亲和力IL-4R，每个细胞的IL-4R分子数范围为1425±207（平均值±标准误）至3831±299（平均值±标准误），解离常数（Kd）范围为112±11皮摩尔至283±71皮摩尔。用IL-4R的cDNA探针进行的IL-4R基因表达的Northern印迹分析显示，所有RCC细胞都呈现出一种4kb的单一mRNA种类。IL-4下调了一种RCC肿瘤细胞系上IL-4R的表面表达。通过研究IL-4对体外肿瘤细胞生长的影响，并将其与IL-4对正常成纤维细胞和内皮细胞系生长的影响进行比较，进一步确定了RCC肿瘤细胞上IL-4R表达的功能。用[³H]胸腺嘧啶掺入法测量，肿瘤细胞生长受到IL-4的抑制，抑制率为20%至68%，呈剂量依赖性。一种针对人IL-4的中和抗体能够逆转IL-4的生长抑制作用。正常人成纤维细胞和内皮细胞系也表达高亲和力IL-4R，然而，IL-4在体外并未抑制它们的生长。事实上，IL-4对它们的生长有适度的刺激作用。综上所述，我们的研究结果有助于制定治疗RCC的策略，其中IL-4R可作为IL-4自身、IL-4毒素疗法或基因疗法的靶点。
