Synthesis of proteoglycan during HL-60 cell differentiation.

Newly synthesized proteoglycans (PG) in proliferating HL-60 cells were labeled with [35S]-sulfate and fractionated on DEAE-cellulose columns. Peak fractions were digested with chondroitinase ABC and separated by paper chromatography. Chondroitin sulfate was identified as the major PG. Treatment of cells with 16 nM TPA resulted in a 1.8-fold increase in total sulfate incorporation into PG, a shift in its location from the cellular to the extracellular compartment, and an increase in the total charge of PG (based on the profile of elution from DEAE-cellulose columns), compared to controls. Incorporation of [3H]-glucosamine into cellular PG was markedly decreased in TPA-treated cells; the sulfate/glucosamine ratio showed a 13.5-fold decrease in the newly synthesized cellular PG. The sulfate/glucosamine ratio, however, was increased by 7.6-fold in secreted PG.