Effects of 1 alpha, 25-dihydroxyvitamin D3 on the human chronic myelogenous leukemia cell line RWLeu-4.
The effects of 1 alpha, 25-dihydroxyvitamin D3 (VD3) on proliferation, differentiation, and macromolecular synthesis in the new Philadelphia chromosome-positive chronic myelogenous leukemia cell line, RWLeu-4, were investigated. Binding of [3H]VD3 was saturable, with approximately 2000-3000 sites/cell, and half-maximal binding occurring at 0.21-0.33 nM. Treatment of RWLeu-4 cells with VD3 induced 24R-hydroxylase activity, a marker of vitamin D3 responsiveness in many tissues. Exposure of RWLeu-4 cells to VD3 also inhibited proliferation and DNA synthesis with a 50% effective dose of 3.5-10 nM within 72 h; in addition, protein and RNA synthesis were inhibited by VD3 treatment. Exposure of RWLeu-4 cells to 5 nM VD3 for 72 h caused 50% of the cells to differentiate into macrophage/monocyte type cells as judged by nitroblue tetrazolium staining and adherence to plastic. Progressive expression of cell surface maturation-specific antigens of the monocyte/macrophage lineage was induced by treatment of RWLeu-4 cells with VD3 for 24 to 72 h at doses that inhibited cellular proliferation. c-myc RNA, which is constitutively expressed in RWLeu-4 cells, increased after 0.5 h of treatment with 50 nM VD3 and then rapidly decreased to barely detectable levels after 4 h of treatment. Finally, the in vitro tyrosine kinase activity associated with the p210bcr-abl oncogene product was decreased approximately 50% by VD3 treatment. Because of the presence of a functional receptor-effector system for VD3 and multiple biological responses to the hormone, these cells provide a unique model system with which to probe the specific effects of VD3 on cell growth and differentiation in chronic myelogenous leukemia.
Lasky
S R
SR
Department of Medicine, Roger Williams General Hospital, Providence, Rhode Island.
Bell
W
W
Huhn
R D
RD
Posner
M R
MR
Wiemann
M
M
Calabresi
P
P
Eil
C
C
D002117:Calcitriol / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D003577:Cytochrome P-450 Enzyme System; D004273:DNA, Neoplasm / Q000096:biosynthesis; D004790:Enzyme Induction / Q000187:drug effects; D016044:Fusion Proteins, bcr-abl / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D066298:In Vitro Techniques; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000473:pathology*; D008264:Macrophages / Q000166:cytology*; D009000:Monocytes / Q000166:cytology*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid / Q000502:physiology; D013250:Steroid Hydroxylases / Q000096:biosynthesis; D014407:Tumor Cells, Cultured; D065668:Vitamin D3 24-Hydroxylase
D004273:DNA, Neoplasm; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D065668:Vitamin D3 24-Hydroxylase; D011505:Protein-Tyrosine Kinases; D016044:Fusion Proteins, bcr-abl; D002117:Calcitriol