Prenylated 4-Hydroxycoumarin derivatives as inducers of CDK4/6-mediated cell cycle arrest: From design and synthesis to in vitro and in vivo evaluation of their anti-breast Cancer activity.
TL;DR
PB1-3 represents a promising prenylated coumarin lead that orchestrates both CDK4/6-Rb cell cycle checkpoint blockade and ROS-dependent mitochondrial apoptosis, offering a valuable scaffold for developing targeted breast cancer therapies, especially for TNBC.
Abstract
Breast cancer is the most frequently diagnosed malignancy in women, and safer, more effective therapies are urgently needed. Inspired by the prenylated coumarin scaffolds of Ferulin C and Miliusol, we rationally designed and synthesized a series of novel 4-hydroxycoumarin derivatives (A, B, and PB series) to develop potent anti-breast cancer agents. Among them, lead compound PB1-3 (7-methoxy, geranyl-substituted) exhibited the most potent antiproliferative activity against MCF-7 (IC₅₀ = 3.13 μM) and 4 T1 (IC₅₀ = 4.28 μM) cells, with high selectivity over normal cells. Structure-activity relationship (SAR) analysis underscored that the combination of a methoxy group and an extended geranyl side chain is crucial for activity. Integrated computational studies (molecular docking, 100 ns MD simulations, and MM-PBSA) confirmed that PB1-3 establishes stable hydrogen-bond and hydrophobic interactions with CDK4/6. Mechanistically, PB1-3 functions as a dual-acting CDK4/6 pathway modulator: it not only directly binds to CDK4/6 but, notably, downregulates their total protein expression, thereby reducing Rb phosphorylation and inducing G0/G1 phase arrest. Concurrently, PB1-3 triggers a potent ROS burst, collapses mitochondrial membrane potential (MMP), upregulates the Bax/Bcl-2 ratio, and activates cleaved caspase-3, driving the intrinsic apoptotic cascade. In a 4 T1 orthotopic syngeneic model, PB1-3 (20 mg/kg, i.p.) significantly suppressed tumor growth comparable to cisplatin, while exhibiting excellent biosafety (LD₅₀ > 2000 mg/kg, no hepatotoxicity/nephrotoxicity) and acceptable oral pharmacokinetics (T₁/₂ = 3.0 h). Collectively, PB1-3 represents a promising prenylated coumarin lead that orchestrates both CDK4/6-Rb cell cycle checkpoint blockade and ROS-dependent mitochondrial apoptosis, offering a valuable scaffold for developing targeted breast cancer therapies, especially for TNBC.