AC-4-130, a powerful inhibitor of the SH2 domain of STAT5, effectively hinders STAT5 activation, dimerization, nuclear translocation, and transcription of genes reliant on STAT5. This compound directly binds to STAT5, ultimately leading to cell cycle arrest and apoptosis in FLT3-ITD-driven leukemic cells. AC-4-130 exhibits notable anti-cancer properties and effectively suppresses abnormal STAT5 activity in acute myeloid leukemia (AML), making it a promising therapeutic option [1].
AS-99 TFA is a first-in-class, potent and selective ASH1L histone methyltransferase inhibitor (IC50= 0.79 μM, Kd= 0.89 μM) with anti-leukemic activity. AS-99 TFA blocks cell proliferation, induces apoptosis and differentiation, downregulates MLL fusion target genes, and reduces the leukemia burden in vivo[1]. AS-99 TFA is tested against a panel of 20 histone methyltransferases, including NSD1, NSD2, NSD3, and SETD2. NO significant inhibition is observed at 50 μM of AS-99 TFA on any of the tested histone methyltransferases, indicating over 100-fold selectivity towards ASH1L[1].AS-99 TFA shows effect on the growth of the MLL leukemia cells (MV4;11, MOLM13, KOPN8, RS4;11) with the GI50 values ranging from 1.8 μM to 3.6 μM[1].AS-99 (1-8 μM; 7 days) TFA also induces apoptosis in the MLL leukemia cells, but not in the K562 cells, as assessed by the quantification of the Annexin V positive cells[1].AS-99 TFA suppresses MLL fusion driven transcriptional programs[1]. AS-99 (30 mg kg; i.p.; q.d., treated for 14 consecutive days) TFA reduces leukemia burden in mice[1].AS-99 TFA is used for in vivo studies in mice, which reveals favorable exposure in plasma upon i.v. and i.p. administration (AUC = 9701 hr* ng mL and 10,699 hr* ng mL, respectively), suitable half-life (~5-6 h) and Cmax >10 μM[1]. [1]. David S. Rogawski, Jing Deng, Hao Li, Tomasz Cierpicki, Jolanta Grembecka, et al. Discovery of first-in-class inhibitors of ASH1L histone methyltransferase with anti-leukemic activity. Nat Commun. 2021 May 14;12(1):2792.