Comparative responsiveness of HL-60, HL-60R, and HL-60R+ (LRARSN) cells to retinoic acid, calcitriol, 9 cis-retinoic acid, and sodium butyrate.
In HL-60 cells, retinoic acid (RA) and 9 cis-RA induce granulocytic differentiation, and calcitriol and sodium butyrate induce monocytic differentiation. To study the role of retinoid resistance on the response to these agents, we investigated their effects in HL-60 cells, retinoid-resistant HL-60R cells, and HL-60R+ cells in which retinoid sensitivity has been restored. In HL-60 cells, cathepsin D (ctsd) mRNA levels are increased by these agents and by cholera toxin after pretreatment with each agent. Calcitriol, 9 cis-RA, and sodium butyrate increase interleukin-8 (IL-8) mRNA expression, and pretreatment with these agents or RA potentiates the stimulation of IL-8 by phorbol ester (TPA). Pretreatment of HL-60 cells with all of the agents confers inducibility of cathepsin L (ctsl) mRNA by TPA in previously unresponsive cells. In HL-60R cells, none of the agents alone or in combination significantly enhances the expression of the ctsd, IL-8, or ctsl mRNAs. Retinoid stimulation (either alone or in combination with the other agents) of the three mRNAs is partially restored in the HL-60R+ cells. Calcitriol does not alter the expression of any of these mRNAs, and only the stimulation of IL-8 mRNA by sodium butyrate is recovered. Treatment with all of the agents inhibits proliferation and stimulates differentiation of the HL-60 cells. RA and calcitriol are unable to inhibit proliferation of the HL-60R cells, whereas only calcitriol fails to inhibit proliferation of the HL-60R+ cells. None of the agents induces differentiation in either the HL-60R or HL-60R+ cells. Therefore, the mutation of the RA receptor alpha is insufficient to account for the altered responses of the HL-60R cells, and there are likely defects in other signaling pathways in these cells. These cells may prove useful in examining the mechanism of cross-resistance between various differentiating agents.
Atkins
K B
KB
Department of Internal Medicine, Veterans Administration Medical Center, Ann Arbor, MI, USA.
Troen
B R
BR
D002087:Butyrates / Q000494:pharmacology*; D020148:Butyric Acid; D002117:Calcitriol / Q000494:pharmacology*; D002402:Cathepsin D / Q000235:genetics; D056668:Cathepsin L; D002403:Cathepsins / Q000235:genetics; D002454:Cell Differentiation / Q000187:drug effects; D003546:Cysteine Endopeptidases; D004351:Drug Resistance; D010450:Endopeptidases; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics; D015473:Leukemia, Promyelocytic, Acute / Q000378:metabolism / Q000473:pathology*; D012333:RNA, Messenger / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014212:Tretinoin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D002087:Butyrates; D016209:Interleukin-8; D012333:RNA, Messenger; D020148:Butyric Acid; D014212:Tretinoin; D002403:Cathepsins; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; C534281:CTSL protein, human; D056668:Cathepsin L; D002402:Cathepsin D; D002117:Calcitriol; D013755:Tetradecanoylphorbol Acetate