Inverse effects of 20K and 22K human growth hormones on the growth of T-47D human breast cancer cells in culture and in nude mice.
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.
Fujikawa
T
T
Department of Biochemistry, School of Medical Sciences, Mie University Faculty of Medicine, Japan.
Kaneko
H
H
Hibasami
H
H
Sakaguchi
K
K
Alam
K S
KS
Tanaka
M
M
Nakashima
K
K
D000818:Animals; D001943:Breast Neoplasms / Q000473:pathology*; D002455:Cell Division / Q000502:physiology*; D019382:Human Growth Hormone / Q000502:physiology*; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D011388:Prolactin / Q000502:physiology; D014407:Tumor Cells, Cultured
D019382:Human Growth Hormone; D011388:Prolactin