Embryonic Ectoderm Development (EED) Inhibitor APG5918 Improves Chronic Kidney Disease- (CKD)-Induced Hemoglobin Insufficiency in Preclinical Models of Anemia

Abstract

Introduction Anemia can be caused by infections, malignancies, CKD, or chemotherapy. Increasing Hb or fetal hemoglobin (HbF) can prevent or reduce anemia-related pathophysiology. Polycomb inhibitory complex 2 (PRC2), consisting of EZH2, EED, and SUZ12, is a subunit of the major transcriptional corepressor complex of BCL11A, and targeting EED may be one novel approach for treatment of patients with anemia. We report the effects of APG-5918, a small-molecule selective EED inhibitor, on Hb and HbF induction in human CD34⁺ hematopoietic stem cells (HSCs) and the efficacy of APG-5918 in a CKD-induced anemia model in vivo. Methods The pharmacodynamic (PD) effects of APG-5918 were evaluated in human cord blood CD34⁺ HSCs by flow cytometry, RT-qPCR, and ELISA. In vivo, the antianemia effect of APG-5918 was evaluated in adenine-induced renal anemic Sprague-Dawley rats. Results APG-5918 inhibited H3K27me3 inCD34⁺ HSCs, the critical epigenetic mark catalyzed by PRC2. APG-5918 also increased γ-globin coding gene ( HBG) and β-globin coding gene ( HBB) mRNA levels in a dose-dependent manner. After 7 days of treatment with APG-5918 at 1 μM, HBG and HBB mRNA increased to 12.36-fold and 4.76-fold of the control group, respectively, which was pharmacologically superior to effects observed with hydroxyurea at 33 µM (~6.53-fold and 2.27-fold increases in HBG and HBB mRNA, respectively). Hb and HbF protein were also upregulated in a dose-dependent manner. A total of 1.69-fold and 1.9-fold increases in HbF and Hb protein expression were observed after 7 days of treatment with APG-5918 at 1 μM.HbF and Hb protein showed no significant difference after hydroxyurea treatment. In an adenine-induced renal anemic rat model, APG-5918 was administered orally once daily at 3 dose levels (5, 15, and 45 mg/kg). Both body weight and the blood parameters erythrocytes, Hb, hematocrit (HCT), and reticulocytes (RET) improved significantly in a dose-dependent manner compared to the model (adenine) group ( p < 0.05, 0.01, or 0.001) (Figure 1). APG-5918 showed similar in vivo efficacy with erythropoietin (EPO): body weight and blood parameters in the group treated with APG-5918 45 mg/kg were comparable to those in the EPO group. In addition, blood parameters in the APG-5918 (15 mg/kg) plus EPO group recovered to the level of the control group, which was superior to the APG-5918 and EPO monotherapy groups. Conclusions APG-5918 demonstrated its effects as a single agent on inhibition of H3K27me3 inCD34⁺ HSCs, HbF and Hb induction, and normalization of hematologic parameters in a CKD-induced anemia model. APG-5918 also showed synergistic antianemia effects when combined with EPO. These findings support APG-5918 as a novel treatment option for CKD-induced anemia.