Keratinocyte growth factor regulates proliferation and differentiation of hematopoietic cells expressing the receptor gene K-sam.
OBJECTIVE
The aim of this study was to establish a new method to overcome the problems of gene therapy targeting hematopoietic cells, namely low transduction efficiency and induction of differentiation during cytokine treatment.


METHODS
The K-sam gene encoding the receptor for keratinocyte growth factor (KGF) was transduced to three factor-dependent hematopoietic cell lines (Ba/F3, 32Dcl3, and UT-7/GM) using retroviral vector, and their proliferation, differentiation, and intracellular signaling were studied. This gene also was transduced to murine bone marrow cells, and proliferation of colony-forming cells (CFCs) by KGF stimulation was examined.


RESULTS
Although KGF is known to target only epithelial cells, all of the three cell lines transduced with K-sam proliferated due to KGF stimulation. Morphologic observation showed that KGF induced proliferation but did not cause significant differentiation of 32D/K-sam cells. KGF treatment increased phosphorylation of ERK1/2 but did not activate STAT molecules. Granulocyte colony-stimulating factor transduced the differentiation signal with the phosphorylation of STAT3 without significant ERK1/2 activation. Proliferation by KGF of murine primary bone marrow cells transduced with K-sam then was examined in liquid culture. KGF treatment significantly increased production of CFCs derived from K-sam-transduced bone marrow cells without causing the exhaustion of immature CFCs.


CONCLUSIONS
KGF could efficiently induce proliferation of hematopoietic cells expressing the K-sam gene without obvious induction of differentiation or exhaustion of immature progenitor cells. The in vitro data are important for further preclinical in vivo study.
Kamata
Tamihiro
T
Division of Hematology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
Hattori
Yutaka
Y
Hamada
Hirofumi
H
Kizaki
Masahiro
M
Terada
Masaaki
M
Ikeda
Yasuo
Y
D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D051523:Fibroblast Growth Factor 7; D005346:Fibroblast Growth Factors / Q000494:pharmacology*; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D051497:Receptor, Fibroblast Growth Factor, Type 2; D017468:Receptors, Fibroblast Growth Factor / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D050796:STAT3 Transcription Factor; D015398:Signal Transduction; D015534:Trans-Activators / Q000378:metabolism; D014161:Transduction, Genetic; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; C496453:FGF7 protein, human; C496454:Fgf7 protein, mouse; D017468:Receptors, Fibroblast Growth Factor; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C494087:Stat3 protein, mouse; D015534:Trans-Activators; D051523:Fibroblast Growth Factor 7; D005346:Fibroblast Growth Factors; C496353:FGFR2 protein, human; C496354:Fgfr2 protein, mouse; D020794:Receptor Protein-Tyrosine Kinases; D051497:Receptor, Fibroblast Growth Factor, Type 2; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases