Expression of 85-kDa protein of adriamycin-resistant tumor cells during hematopoietic differentiation of THP-1 and HEL cells.
An 85-kDa protein was identified in adriamycin-resistant tumor cells recognized by monoclonal antibody MRK-20. Recently, the monoclonal antibody MRK-20 was found to be reactive to human peripheral mononuclear cells. In order to investigate the molecular function of the 85-kDa protein, we carried out flow cytometric analysis of the expression of the 85-kDa protein during monocytic differentiation of the hematopoietic cells. Human myelomonocytic leukemia THP-1 cells were induced to differentiate into macrophage-like cells by treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA). A maximum of 55% of the cells expressed the 85-kDa protein along with the CD-14 antigen, which is a surface marker of monocytes and macrophages. The kinetic analysis revealed that the 85-kDa protein appeared prior to the expression of the CD-14 antigen. The 85-kDa protein was also coexpressed with CD-14 in THP-1 cells that were induced to differentiate by recombinant tumor necrosis factor-alpha, which is one of the physiological inducers of monocytic differentiation. In human erythroleukemia, HEL cells, the 85-kDa protein was constitutively coexpressed with CD-14. The expression of both the 85-kDa protein and CD-14 was drastically reduced during the megakaryocytic differentiation of the HEL cells with TPA. These results suggest that the 85-kDa protein could be expressed on monocytic cells as well as CD-14 and that the expression of the 85-kDa protein might be regulated at an earlier stage of monocytic differentiation of hematopoietic cells than the expression of CD-14.
Institute of Applied Microbiology, University of Tokyo.
S
S
Ishii
M
M
Naito
M
M
Masuda
T
T
Tsuruo
D015703:Antigens, CD / Q000032:analysis*; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis*; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D004317:Doxorubicin / Q000494:pharmacology; D004351:Drug Resistance / Q000235:genetics; D006801:Humans; D004915:Leukemia, Erythroblastic, Acute; D015479:Leukemia, Myelomonocytic, Acute; D018950:Lipopolysaccharide Receptors; D008533:Megakaryocytes / Q000187:drug effects; D008565:Membrane Proteins / Q000032:analysis*; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D015815:Cell Adhesion Molecules; D018950:Lipopolysaccharide Receptors; D008565:Membrane Proteins; D014409:Tumor Necrosis Factor-alpha; D004317:Doxorubicin; D013755:Tetradecanoylphorbol Acetate