RARA SE+ pAML cells are sensitive to tamibarotene.RARA SE+ pAML samples per cell lines are in red, RARA SE− pAML samples per cell lines in blue, and APL cell line in gray. Experiments were conducted in biologic triplicates (except where noted), and all experiments were repeated at least once as independent, asynchronous experiments to confirm results, with representative data from one independent experiment shown. (A) RARA messenger (messenger RNA [mRNA]) levels in pAML cell lines (Kasumi1, MV4;11, THP1), an APL cell line (NB4), and patient samples (technical replicates n = 3 per cell line or sample). (B) Effect of tamibarotene (100 nM) on cell viability over time. Viability was normalized to the viability of dimethyl sulfoxide (DMSO)-treated cells measured at the same time points. (C) CD38 positivity in response to tamibarotene (100 nM) after 72 hours’ treatment. Expression of other differentiation markers in response to tamibarotene (100 nM) after 72 hours’ treatment: CD66 (D) and CD11c (E). (F) Induction of apoptosis by 100 nM tamibarotene in pAML cell lines and samples after 72 hours’ treatment. (G) DHRS3 mRNA expression fold change after 24 hours’ tamibarotene treatment (100 nM). * P < .05; **.001 < P < .01; ***.0001 < P < .001; ****P < 0.0001.