Quantitative morphological aspects of granulocytic differentiation induced in HL-60 cells by dimethylsulfoxide and retinoic acid

HL-60 cells differentiate to mature granulocytes when cultured with DMSO or retinoic acid. These two drugs can induce different expression of phenotypic or functional properties in these cells. The morphological characteristics of the differentiation sequences elicited by these two drugs have been therefore evaluated by a quantitative cytological analysis technique using a SAMBA 200 cell image processor. The maturation sequences induced by DMSO or retinoic acid differed mainly in nuclear geometry and cytoplasmic granules expression. Multivariate statistical analyses of data reveal that DMSO and retinoic acid elicited granulocytic maturation through two separate morphological pathways which can be individualized as early as 24 hr after differentiation induction. Image processing may therefore offer an interesting tool for studying new drugs with differentiation potential in chemotherapy.