INSULIN-LIKE GROWTH-FACTORS (IGFS), IGF RECEPTORS, AND IGF-BINDING PROTEINS IN PRIMARY CULTURES OF PROSTATE EPITHELIAL-CELLS
INSULIN-LIKE GROWTH-FACTORS (IGFS), IGF RECEPTORS, AND IGF-BINDING PROTEINS IN PRIMARY CULTURES OF PROSTATE EPITHELIAL-CELLS
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DOI：
10.1210/jcem-73-2-401
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发表时间：
1991-08-01
影响因子：
5.8
通讯作者：
ROSENFELD, RG
中科院分区：
文献类型：
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作者：
COHEN, P;PEEHL, DM;ROSENFELD, RG
胰岛素样生长因子（IGFs）是与IGF受体和IGF结合蛋白（igfbp）结合具有高亲和力和特异性的强效分裂原。我们研究了这三组蛋白在无血清条件下原代培养的前列腺上皮细胞（PEC）中的作用。IGF- i和IGF- ii与PEC制备的粗膜的亲和交联显示了丰富的1型IGF受体，而没有2型IGF受体的证据。来自PEC的条件培养基（CM）的Western配体印迹显示存在两个特定的IGFBP带，与先前在精浆中显示的相似，摩尔重量约为31和24 kDa。用IGFBP-2抗体可免疫沉淀31-kDa条带，两条带均不能用内糖苷酶- f去糖基化。用PEC制备的poly(A)+ RNA与hIGFBP-1、-2和3的cdna进行Northern blot分析，只记录了hIGFBP-2 mRNA的表达。PEC无血清条件的改变没有显著改变PEC CM的IGFBP谱。研究了IGF-I、IGF-II和胰岛素刺激PEC克隆生长的能力。IGF-I刺激PEC生长，ED50为0.1 ng/mL。在刺激PEC生长方面，IGF-II和胰岛素分别比IGF-I低1和3个数量级。PEC CM放射免疫检测IGF-I和IGF-II水平低于检测水平。综上所述，我们认为IGF是培养中PEC的重要生长刺激物，它们的作用是通过1型IGF受体介导的，PEC产生的hIGFBP-2和一个24 kda的IGFBP可能调节这些细胞的IGF作用。
Insulin-like growth factors (IGFs) are potent mitogens that bind with high affinity and specificity to IGF receptors and IGF-binding proteins (IGFBPs). We studied the roles of these three groups of proteins in prostate epithelial cells (PEC) in primary culture grown under serum-free conditions. Affinity cross-linking of IGF-I and IGF-II to crude membranes prepared from PEC revealed an abundance of type 1 IGF receptors and no evidence of type 2 IGF receptors. Western ligand blots of conditioned media (CM) from PEC demonstrated the presence of two specific IGFBP bands similar to those previously demonstrated in seminal plasma, with approximate mol wt of 31 and 24 kDa. The 31-kDa band was immunoprecipitable with an antibody to IGFBP-2, and neither band could be deglycosylated with endoglycosidase-F. Northern blot analysis of poly(A)+ RNA prepared from PEC with cDNAs for hIGFBP-1, -2, and 3 documented the expression of mRNA for hIGFBP-2 only. Modifications of the serum-free conditions of PEC did not significantly alter the IGFBP profile of PEC CM. The ability of IGF-I, IGF-II, and insulin to stimulate clonal growth of PEC was examined. IGF-I stimulated PEC growth with an ED50 of 0.1 ng/mL. IGF-II and insulin, respectively, were 1 and 3 orders of magnitude less effective than IGF-I in stimulating the growth of PEC. Radioimmunoassayable IGF-I and IGF-II levels in PEC CM were below the assay detection levels. In conclusion, we suggest that IGFs are important growth stimulators of PEC in culture, that their actions are mediated through the type 1 IGF receptor, and that PEC produce hIGFBP-2 and a 24-kDa IGFBP which may modulate IGF action in these cells.