REVERSIBLE EFFECTS OF RETINOIC ACID ON GLYCOSAMINOGLYCAN SYNTHESIS DURING DIFFERENTIATION OF HL-60 LEUKEMIA-CELLS

  • 1 January 1985
    • journal article
    • research article
    • Vol. 45  (5) , 2092-2097
Abstract
Glycosaminoglycans (GAG) play an important role in cell-cell and cell-substratum interactions and undergo specific changes during neutrophil development. Previous studies have shown that both dimethyl sulfoxide and 4-.beta.-phorbol-12-.beta.-myristate-13-.alpha.-acetate decreased GAG production by a hypoxanthine-guanine phosphoribosyl transferase-deficient clone of HL-60 promyelocytic leukemia cells prior to the appearance of a mature myeloid or monocytoid phenotype. To expand these investigations further, GAG were analyzed by cetylpyridinium chloride precipitation and DEAE-Sephacel ion-exchange chromatography after labeling of parental HL-60 cultures with [35S]sulfate and D-[3H]glucosamine for 6 h, following treatment with 1 .mu.M all-trans retinoic acid (RA). Chondroitin sulfate represented the major GAG species produced, although endo-.beta.-galactosidase-sensitive undersulfated macromolecules which possibly might be keratan sulfate, were also identified. GAG production decreased over a time period of 144 h in culture. RA treatment reduced the amount of radiolabeled cell-associated GAG by 50% after 48, 96 and 144 h of exposure. In contrast, commitment to myelocytic maturation of the majority (i.e., .apprx. 60%) of the cells occurred between 72 and 96 h of RA treatment. Concurrently with the appearance of mature granulocytic cells, 2/3 of the radiolabeled GAG were recovered from the medium, compared to 1/3 in untreated cultures, a phenomenon that resulted in an overall alteration in the distribution of GAG. When RA was removed by washing after either 48 h (i.e., precommitment to differentiation) or 96 h (i.e., postcommitment to differentiation), a 1.5-3.5-fold increase in GAG production was noted 48 h later; this increase was unrelated to the medium change or to alterations in cell cycle distribution. The amounts of endo-.beta.-galactosidase-sensitive macromolecules were unaltered. Thus, although 1 .mu.M RA inhibited the synthesis of chondroitin sulfate by HL-60 leukemia cells, this inhibition was reversible by removal of the drug and appeared to be unrelated to the commitment to myelocytic maturation. [The use of RA as an antineuplastic drug was outlined.].