Fujikawa T, Kaneko H, Hibasami H, Sakaguchi K, Alam K S, Tanaka M, Nakashima K
Department of Biochemistry, School of Medical Sciences, Mie University Faculty of Medicine, Japan.
Biochem Mol Biol Int. 1998 Nov;46(4):719-24. doi: 10.1080/15216549800204252.
The major form of human growth hormone (22K hGH) stimulates the growth of T-47D human breast cancer cells in culture and in nude mice by binding to their receptors for growth hormone and prolactin. Another isoform of hGH having a smaller molecular mass (20K hGH) is known to show different binding affinities to these receptors. In this study, we have analyzed the effects of 20K hGH on the growth of T-47D cells in vitro and in vivo. 20K hGH (50 ng/ml) inhibited the proliferation and DNA synthesis of T-47D cells cultured in the presence and absence of 17 beta-estradiol (100 ng/ml), while 22K hGH (50 ng/ml) promoted the cellular growth. In estradiol-treated nude mice, 22K hGH (100 micrograms) remarkably promoted the growth of T-47D tumor, but 20K hGH again suppressed the tumor growth significantly. The results suggest the presence of different signal pathways for these two hGH isoforms and imply a possible clinical application for 20K hGH.
人类生长激素的主要形式（22K hGH）通过与T-47D人乳腺癌细胞的生长激素和催乳素受体结合，在培养物和裸鼠中刺激其生长。已知另一种分子量较小的hGH同工型（20K hGH）对这些受体表现出不同的结合亲和力。在本研究中，我们分析了20K hGH对T-47D细胞体外和体内生长的影响。20K hGH（50 ng/ml）在有和没有17β-雌二醇（100 ng/ml）存在的情况下，均抑制培养的T-47D细胞的增殖和DNA合成，而22K hGH（50 ng/ml）则促进细胞生长。在经雌二醇处理的裸鼠中，22K hGH（100微克）显著促进T-47D肿瘤的生长，但20K hGH再次显著抑制肿瘤生长。结果表明这两种hGH同工型存在不同的信号通路，并暗示20K hGH可能具有临床应用价值。
