Regulation of myeloid cell proliferation and differentiation in the bone marrow is mediated, in part, by the interaction of integrins on early myeloid cells with the extracellular matrix proteins secreted by stromal cells. To further define adhesive protein receptors of early myeloid cells, we examined the expression of the integrin GPIIb-IIIa (α(IIb)β3) in leukemic cell lines KG-1a, KG-1, and HL-60, that represent early stages of myeloid differentiation. All three cell lines expressed surface GPIIb-IIIa as measured by flow cytometry and by binding of 125-anti-GPIIb-IIIa monoclonal antibody. Preincubation of cells with human AB serum or platelet releasate increased GPIIb-IIIa surface expression. GPIIb transcripts were identified in all three cell lines by Northern blot analysis. Furthermore, we readily detected GPIIb transcripts in fluorescence activated cell sorted (FACS) myeloid cells from normal human bone marrow by RT-PCR. Cloning and sequencing of the PCR products established the identity of GPIIb transcripts in the leukemic cell lines and CD34+/CD33+ normal bone marrow cells. Since the normal myeloid cells also demonstrated markers corresponding to the maturational stage of KG-1a/KG-1 cells, we propose that GPIIb-IIIa may serve as a myeloid differentiation antigen and as a key integrin of myeloid precursors.
Bibliographical noteFunding Information:
Supported in part by grants awarded by the National Institutes of Health HL38171, the American Cancer Society IN-176-A and the Flow Cytometry Facility in the Molecular Resource Center of Excellence the University of Tennessee, Memphis. J.E.W. is the recipient of the American Cancer Society Career Development Award. R.R. is a Research Career Scientist of the Department of Veteran’s Affairs. L.K.J. is an Established Investigator of the American Heart Association. We would like to thank Ms. Amy Adcock for the preparation of this manuscript.
- Glycoprotein IIb-lIIa
- Myeloid differentiation antigen
- Myeloid leukemic cell lines
- Myeloid precursor cell