Expression and function of β‐adrenergic receptors in human hematopoietic cell lines

We investigated the expression and functional characteristics of beta-adrenoceptors in a panel of 10 phenotypically different human hematopoietic cell lines. A binding assay with [125I]iodocyanopindolol as the ligand revealed that cell lines of myelomonocytic or histiocytic derivation (HL-60, ML-2, RC-2A, U-937) expressed high numbers of beta-adrenoceptors. An intermediate density of receptors was found in a non-T, non-B cell leukemia line (Nall-1), whereas T-cell (JM, CCRF-CEM), B-cell (Raji) or erythroleukemic cell lines (K-562, HEL) displayed minimal or undetectable binding of the radioligand. Isoprenaline-stimulated cAMP production by the cells correlated to their extent of beta-adrenoceptor expression. Southern blot hybridization analysis of genomic DNA from the cell lines with a 32P-labelled beta 2-adrenoceptor cDNA probe revealed no evidence for major rearrangement or amplification of the receptor gene. Incubation with isoprenaline in vitro suppressed the proliferation of the receptor-rich RC-2A cells but did not affect the growth rate of the receptor-deficient K-562 cells. Treatment with propranolol slightly enhanced the proliferation of the RC-2A cells but did not markedly alter the growth rate of two other cell lines, regardless of their beta-adrenoceptor status. These findings indicate a regulatory influence by the sympathoadrenergic system on selected cells of the myelomonocytic lineage.