The production of sulfated proteoglycans was compared in mature peripheral blood granulocytes and monocytes and HL-60 promyelocytic leukemia cells. We found that HL-60 cells synthesized 5-10 times more proteoglycans than peripheral blood leukocytes. Differentiation of HL 60 cells toward mature monocytes by treatment with 12-O-tetradecanoyl-phorbol-13-acetate (TPA) or towards granulocytes by treatment with retinoic acid or dibutyryl cyclic adenosine-3′,5′-monophosphate (dbcAMP) resulted in a small (20-30%) decrease in sulfated proteoglycan biosynthesis. Chondroitin sulfate was found to be the predominant proteoglycan produced by monocytes, PMN and undifferentiated HL-60 cells. Differentiated HL-60 cells produced chondroitin sulfate as well as sulfated proteoglycans sensitive to nitrous acid degradation. Similar results were observed in TPA, dbcAMP and retinoic acid differentiated HL-60 cells indicating that the changes in proteoglycan biosynthesis observed were independent of the developmental pathway. Using specific monoclonal antibodies and flow cytometry, we also found that HL-60 cells and monocytes produced chondroitin 4-sulfate, chondroitin-6-sulfate and chondroitin-O-sulfate while PMN only produced chondroitin-4 sulfate. In addition, although there were no significant differences in antibody binding to undifferentiated and differentiated HL-60 cells, the tumor cells bound 5-20 times more of the antibodies than the peripheral blood leukocytes. Our data demonstrate that sulfated proteoglycan production by HL-60 cells is distinct from PMN and monocytes. In addition, the fact that differentiated HL-60 cells continue to synthesize larger amounts of the proteoglycans than the peripheral blood leukocytes indicates these cells have not completely matured.
All Science Journal Classification (ASJC) codes
- Cancer Research
- HL-60 cells