Expression of high-affinity interleukin 4 receptors on murine sarcoma cells and receptor-mediated cytotoxicity of tumor cells to chimeric protein between interleukin 4 and Pseudomonas exotoxin.
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.
Puri
R K
RK
Division of Cytokine Biology, Food and Drug Administration, Bethesda, Maryland 20892.
Ogata
M
M
Leland
P
P
Feldman
G M
GM
FitzGerald
D
D
Pastan
I
I
D000818:Animals; D001426:Bacterial Proteins / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D005098:Exotoxins / Q000494:pharmacology*; D015847:Interleukin-4 / Q000378:metabolism / Q000494:pharmacology*; D051379:Mice; D009363:Neoplasm Proteins / Q000096:biosynthesis; D012334:RNA, Neoplasm / Q000032:analysis*; D019948:Receptors, Interleukin-4; D011975:Receptors, Mitogen / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000494:pharmacology*; D012509:Sarcoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D014407:Tumor Cells, Cultured / Q000378:metabolism / Q000473:pathology
D001426:Bacterial Proteins; D005098:Exotoxins; C059989:IL-4-PE40 protein, recombinant; D009363:Neoplasm Proteins; D012334:RNA, Neoplasm; D019948:Receptors, Interleukin-4; D011975:Receptors, Mitogen; D011993:Recombinant Fusion Proteins; D015847:Interleukin-4