INSULIN-LIKE GROWTH-FACTOR BINDING-PROTEIN SECRETION BY BREAST-CARCINOMA CELL-LINES - CORRELATION WITH ESTROGEN-RECEPTOR STATUS
INSULIN-LIKE GROWTH-FACTOR BINDING-PROTEIN SECRETION BY BREAST-CARCINOMA CELL-LINES - CORRELATION WITH ESTROGEN-RECEPTOR STATUS
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DOI：
10.1210/endo-127-6-2679
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发表时间：
1990-12-01
期刊：
影响因子：
4.8
通讯作者：
OSBORNE, CK
中科院分区：
文献类型：
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作者：
CLEMMONS, DR;CAMACHOHUBNER, C;OSBORNE, CK
乳腺肿瘤细胞系已被证明可以分泌几种不同的多肽生长因子，尽管胰岛素样生长因子（igf）的结果存在矛盾。相比之下，有限数量的乳腺肿瘤细胞系已经明确显示可以分泌高亲和力的IGF结合蛋白（igfbp）来修饰IGF的作用。为了表征乳腺肿瘤细胞系分泌的igfbp类型，从7个独立的肿瘤细胞系中收集条件培养基，其中3个为雌激素受体（ER）阴性，4个为ER阳性。所有三种ER阴性细胞系，MDA-231， MDA-330和HS578T，分泌49,000和43,000 Mr （IGFBP-3）结合蛋白以及29,000 （IGFBP-1）和24,000 Mr.相反，所有四种ER阳性细胞系分泌34,000 （IGFBP-2）或24,000 Mr形式，没有分泌49,000,43,000或29,000 Mr形式。BT-20是一种内质网信使RNA （mRNA）阳性但内质网蛋白阴性的细胞系，主要分泌34,000 Mr的蛋白。24 h内释放的IGFBP总活性在0.4 ~ 5.6 nM（相当于IGFBP-1）之间，ER阳性和阴性细胞系间无显著差异。产生34000和24000 Mr形式的MCF-7细胞在雌激素刺激后IGFBP的分泌增加了1.8倍。免疫印迹和IGFBP-1特异性RIA显示，只有ER阴性细胞系MDA-330、MDA-231和HS578T分泌这种形式。对编码该蛋白的mRNA进行Northern blotting分析表明，MDA-330和MDA-231都含有与IGFBP-1互补DNA （cDNA）探针杂交的1.6千碱基mRNA。其他细胞系的免疫印迹分析显示，只有ER阳性细胞系分泌的34,000 Mr形式与IGFBP-2抗血清发生反应。将三个ER阴性细胞系的条件培养基暴露于n -糖聚糖酶后发现，49,000和43,000 Mr形式的IGFBP被糖基化，因此可能代表IGFBP-3。我们得出结论，ER阴性细胞系分泌三种形式的igfbp， IGFBP-1， IGFBP-3和24000 Mr形式。相比之下，ER阳性细胞系主要分泌IGFBP-2和24000 Mr形式，但不分泌IGFBP-3或1。雌激素会刺激这种形式的分泌。这些发现表明，乳腺肿瘤细胞系分泌特定形式的igfbp， ER阴性和ER阳性肿瘤细胞系产生的igfbp的形式不同。这些发现可能有助于理解IGFs在控制乳腺癌细胞增殖中的作用。
Breast tumor cell lines have been shown to secrete several distinct polypeptide growth factors, although conflicting results exist for the insulin-like growth factors (IGFs). In contrast a limited number of breast tumor cell lines have definitely been shown to secrete the high affinity IGF binding proteins (IGFBPs) that modify IGF actions. To characterize the types of IGFBPs that are secreted by breast tumor cell lines, conditioned medium was collected from seven separate tumor cell lines, three of which were estrogen receptor (ER) negative, and four of which were ER positive. All three of the ER negative cell lines, MDA-231, MDA-330, and HS578T, secreted binding proteins of 49,000 and 43,000 Mr (IGFBP-3) as well as 29,000 (IGFBP-1) and 24,000 Mr. In contrast, all four ER positive cell lines secreted 34,000 (IGFBP-2) or 24,000 Mr forms, and none secreted the 49,000 and 43,000 or 29,000 Mr forms. BT-20, a cell line that is positive for ER messenger RNA (mRNA) but negative for ER protein, secreted predominantly a 34,000 Mr protein. The amount of total IGFBP activity released in 24 h ranged between 0.4 and 5.6 nM equivalents of IGFBP-1, and there was no significant difference between the ER positive and negative cell lines. The MCF-7 cells that produced predominantly 34,000 and 24,000 Mr forms showed a 1.8-fold increase in IGFBP secretion after estrogen stimulation. Immunoblotting and a specific RIA for IGFBP-1 showed that only the ER negative lines MDA-330, MDA-231, and HS578T secreted this form. Northern blotting analysis for the mRNA encoding this protein showed that both MDA-330 and MDA-231 contained single 1.6 kilobase mRNA species that hybridized with an IGFBP-1 complementary DNA (cDNA) probe. Immunoblotting analysis of the other cell lines showed that only the 34,000 Mr form secreted by the ER positive cell lines reacted with IGFBP-2 antisera. Exposure of the conditioned media from the three ER negative cell lines to N-glycanase revealed that the 49,000 and 43,000 Mr forms of IGFBP were glycosylated and therefore probably represent IGFBP-3. We conclude that ER negative cell lines secrete three forms of IGFBPs, IGFBP-1, IGFBP-3, and a 24,000 Mr form. In contrast, the ER positive cell lines secrete predominantly IGFBP-2 and the 24,000 Mr form but do not secrete IGFBP-3 or 1. Secretion of these form is stimulated by estrogen. These findings indicate that breast tumor cell lines secrete specific forms of IGFBPs and that ER negative and positive tumor cell lines differ in the forms of IGFBPs that are produced. These findings may have implications for understanding the role of the IGFs in controlling breast carcinoma cell proliferation.