Stem Cells, Vol 11, 303-311, Copyright © 1993 by AlphaMed Press
Hemoregulatory peptide (HP5b) dimer effects on normal and malignant cells in culture
S Frostad, T Kalland, A Aakvaag and OD Laerum
Gade Institute, Department of Pathology, University of Bergen, Haukeland Hospital, Norway.
The dimer of the hemoregulatory peptide HP5b has been investigated for
biological effects on various cell types in culture including mouse
granulocyte-macrophage colony forming units (CFU-GM) from agar and murine
long-term bone marrow culture (LTBMC). While CFU-GM were significantly
stimulated in both systems, mitogen activation of mouse T, B and natural
killer (NK) cells was not affected. Peptide treated mouse 3T3 fibroblasts
reached a higher saturation density than controls; otherwise no effect was
seen. A series of malignant cell lines was also tested. On a human
glioblastoma cell line (GaMg) and rat glioma cell line (BT5C) a slight but
significant stimulatory effect was found, while human mammary carcinoma
cells (MCF7) were not affected. On SC1 mouse lymphoma cells a slight
stimulation of cell growth was seen during the first part of exponential
growth. Since HP5b acts as a stimulator for stromal cell secretion of other
growth factors, supernatants from a human bone marrow stromal cell line
stimulated with HP5b were tested on various cell lines. The effects of the
supernatants on cell growth of the tested cell lines were not affected by
HP5b treatment. Taken together with available in vivo data, the results
indicate that the hemoregulatory peptide is a selective stimulator of
myelopoiesis.
