Yamada Y, Serrero G
W. Alton Jones Cell Science Center, Lake Placid, NY 12946.
Proc Natl Acad Sci U S A. 1988 Aug;85(16):5936-40. doi: 10.1073/pnas.85.16.5936.
An insulin-independent teratoma-derived cell line, called 1246-3A, has been isolated from the adipogenic cell line 1246, which stringently requires insulin for proliferation. The 1246-3A cell line, which can proliferate in the absence of exogenous insulin, produces in its conditioned medium a growth factor similar to pancreatic insulin by its biological and immunological properties. This factor, called "insulin-related factor" (IRF), was purified and iodinated to study its binding to cell surface receptors. 125I-labeled IRF binding to intact 1246-3A cells is lower than to 1246 cells. Cell surface binding can be restored by culturing the 1246-3A cells in the presence of an anti-porcine insulin monoclonal antibody or by acid prewash of the cells prior to performing the binding. Scatchard analysis of binding indicates that IRF secreted by the 1246-3A cells partially occupies high-affinity binding sites on the producer cells. Moreover, insulin monoclonal antibody inhibits the proliferation of the IRF-producing 1246-3A cells, suggesting that these cells are dependent on the secreted IRF for growth in culture. We conclude that the insulin-related factor secreted by the insulin-independent 1246-3A cells stimulates their proliferation in an autocrine fashion.
一种不依赖胰岛素的畸胎瘤衍生细胞系，称为1246 - 3A，已从成脂细胞系1246中分离出来，后者的增殖严格依赖胰岛素。1246 - 3A细胞系在无外源性胰岛素的情况下能够增殖，其条件培养基中产生一种生长因子，从生物学和免疫学特性来看类似于胰腺胰岛素。这种因子被称为“胰岛素相关因子”（IRF），经过纯化和碘化处理以研究其与细胞表面受体的结合。125I标记的IRF与完整的1246 - 3A细胞的结合低于与1246细胞的结合。通过在抗猪胰岛素单克隆抗体存在的情况下培养1246 - 3A细胞，或者在进行结合之前对细胞进行酸洗，可以恢复细胞表面的结合。结合的Scatchard分析表明，1246 - 3A细胞分泌的IRF部分占据了产生细胞上的高亲和力结合位点。此外，胰岛素单克隆抗体抑制产生IRF的1246 - 3A细胞的增殖，这表明这些细胞在培养中生长依赖于分泌的IRF。我们得出结论，不依赖胰岛素的1246 - 3A细胞分泌的胰岛素相关因子以自分泌方式刺激其增殖。
