Hochscheid R, Jaques G, Wegmann B
Department of Internal Medicine, Division of Hematology/Oncology, Philipps-University, Baldingerstrasse, D-35033 Marburg, Germany.
J Endocrinol. 2000 Sep;166(3):553-63. doi: 10.1677/joe.0.1660553.
IGF-I and IGF-II are potent mitogens, postulated to exert autocrine/paracrine effects on growth regulation in human lung cancer. Their proliferative effects are modulated by IGF-binding proteins (IGFBPs), which are found in conditioned medium (CM) of lung cancer cell lines. The biological role of the IGFBPs, which are ontogenetically and hormonally regulated, is not fully understood. Both inhibitory and stimulatory effects on cell growth have been demonstrated. Exogenous IGFBP-3 has been consistently shown to block IGF action, inhibiting cell growth in vitro. In order to evaluate the action of endogenously produced IGFBP-3 on cell growth in lung cancer, we stably transfected the non-small cell lung cancer cell line NCI-H23 with human IGFBP-3 cDNA (resulting in NCI-H23 pOPI3/BP-3) or with the vector pOPI3CAT as control (resulting in NCI-H23 pOPI3CAT). RT-PCR confirmed expression of IGFBP-3-specific mRNA in NCI-H23 pOPI3/BP-3, but not in N! CI-H23 or NCI-H23 pOPI3CAT. Western ligand blot and Western immunoblot analysis of CMs yielded strong signals of the characteristic 40-44 kDa human IGFBP-3 protein in NCI-H23 pOPI3/BP-3. An IGFBP-3 ELISA demonstrated a 20-fold increase in IGFBP-3 protein expression in NCI-H23 pOPI3/BP-3 as compared with NCI-H23. The growth of NCI-H23 pOPI3/BP-3 in serum-containing medium was significantly slower (1.7-fold) than that of NCI-H23 or the vector-transfected control NCI-H23 pOPI3CAT. While the proliferation rate of parental and vector-transfected cells could be stimulated by IGF-I, IGF-II, IGF-I analog Long R(3) IGF-I or insulin, that of NCI-H23 pOPI3/BP-3 could not. Xenotransplantation in nude mice resulted in marked tumor growth after the injection of NCI-H23 or NCI-H23 pOPI3CAT, but absent or minimal growth for the IGFBP-3-transfected cell line. These data suggest that IGFBP-3 is a potent inhibitor of cell growth in human lung cancer c! ell lines and may impair tumorigenicity in vivo.
胰岛素样生长因子-I（IGF-I）和胰岛素样生长因子-II（IGF-II）是强效促有丝分裂原，据推测它们对人类肺癌的生长调节发挥自分泌/旁分泌作用。它们的增殖作用受到胰岛素样生长因子结合蛋白（IGFBPs）的调节，这些蛋白存在于肺癌细胞系的条件培养基（CM）中。IGFBPs的生物学作用在个体发育和激素水平上受到调节，目前尚未完全明确。对细胞生长既有抑制作用也有刺激作用已得到证实。外源性IGFBP-3一直被证明能阻断IGF的作用，在体外抑制细胞生长。为了评估内源性产生的IGFBP-3对肺癌细胞生长的作用，我们用人类IGFBP-3 cDNA稳定转染非小细胞肺癌细胞系NCI-H23（得到NCI-H23 pOPI3/BP-3），并用载体pOPI3CAT作为对照（得到NCI-H23 pOPI3CAT）。逆转录聚合酶链反应（RT-PCR）证实NCI-H23 pOPI3/BP-3中存在IGFBP-3特异性mRNA的表达，但在NCI-H23或NCI-H23 pOPI3CAT中未检测到。对条件培养基进行Western配体印迹和Western免疫印迹分析显示，NCI-H23 pOPI3/BP-3中有特征性的40 - 44 kDa人类IGFBP-3蛋白的强信号。IGFBP-3酶联免疫吸附测定（ELISA）表明，与NCI-H23相比，NCI-H23 pOPI3/BP-3中IGFBP-3蛋白表达增加了20倍。在含血清培养基中，NCI-H23 pOPI3/BP-3的生长明显比NCI-H23或载体转染的对照NCI-H23 pOPI3CAT慢（1.7倍）。虽然亲本细胞和载体转染细胞的增殖率可被IGF-I、IGF-II、IGF-I类似物长R(3)IGF-I或胰岛素刺激，但NCI-H23 pOPI3/BP-3的增殖率则不能。将细胞异种移植到裸鼠体内，注射NCI-H23或NCI-H23 pOPI3CAT后肿瘤明显生长，但IGFBP-3转染细胞系的肿瘤生长不明显或极小。这些数据表明，IGFBP-3是人类肺癌细胞系中细胞生长的强效抑制剂，并可能在体内损害肿瘤发生能力。
