AC-7

WD40 repeat-containing protein 5 (WDR5) is a core component of the SET1/mixed lineage leukemia (MLL) complex that regulates gene expression via H3K4 methylation and plays a key role in maintaining oncogenic gene expression programs, particularly in MLL1-rearranged leukemias. In this study, we leveraged a microprotein, endogenous microprotein binder of WDR5 (EMBOW), to develop peptide-based inhibitors that specifically targeted WDR5. Through comprehensive biophysical analyses and high-resolution structural studies, we revealed that EMBOW mainly bound to the WDR5 interaction (WIN) site of WDR5. Structure-guided optimization led to the development of EMBOW-derived peptides, notably Ac7, which exhibited high affinity for WDR5 (K_d = 9.17 ± 4.01 nM). These peptides effectively inhibited H3K4 methylation, suppressed oncogenic gene expression, and impeded leukemia cell proliferation in vitro. Importantly, in xenograft mouse models, Ac7 demonstrated significant anti-tumor activity with low toxicity. This work offers a promising strategy for targeting epigenetic regulators with peptide-based therapeutics, providing a foundation for innovative treatments in leukemia.

AKT is one of the overexpressed targets in nonsmall cell lung cancer (NSCLC) and plays an important role in its progression and offers an attractive target for the therapy. The PI3K/AKT/mTOR pathway is upregulated in NSCLC. Acridone is an important heterocycle compound which treats cancer through various mechanisms including AKT as a target. In the present work, the study was designed to evaluate the safety profile of three acridone derivatives (AC‐2, AC‐7, and AC‐26) by acute and repeated dose oral toxicity. In addition to this, we also checked the pAKT overexpression and its control by these derivatives in tumor xenograft model. The results from acute and repeated dose toxicity showed these compounds to be highly safe and free from any toxicity, mortality, or significant alteration in body weight, food, and water intake in the rats. In the repeated dose toxicity, compounds showed negligible variations in a few hematological parameters at 400 mg/kg. The histopathology, biochemical, and urine parameters remained unchanged. The xenograft model study demonstrated AC‐2 to be inhibiting HOP‐62 induced tumor via reduction in p‐AKT1 (Ser473) expression significantly. In immunofluorescence staining AC‐2 treated tissue section showed 2.5 fold reduction in the expression of p‐AKT1 (Ser473). Histopathology studies showed the destruction of tumor cells with increased necrosis after treatment. The study concluded that AC‐2 causes cell necrosis in tumor cells via blocking the p‐AKT1 expression. The findings may provide a strong basis for further clinical applications of acridone derivatives in NSCLC.