Synthesis of Antiproliferative N-Chalconyl Imidazolidones and Mechanistic Evaluation of Prototype N-CIMZ 1 as a Macrophage-Modulating Antimitotic Agent

Background/Objectives: To address current aggressive breast cancer challenges, a novel series of eight N-chalconyl imidazolidone derivatives (N-CIMZs 1–8) was synthesized and evaluated for direct cytotoxicity and immunomodulation via macrophage polarization. Methods: Following antiproliferative screening against four representative breast cancer lines, the prototype candidate N-CIMZ 1 was selected for cell cycle and scratch-wound healing assays in MCF-7 cells. Multi-parametric flow cytometry on human THP-1 macrophages tracked cellular stress (γH2AX), metabolic markers (iNOS), and surface dynamics (LAP (TGF-β1), CD163, CD206, CD209). Results: N-CIMZ 1 acted as an antimitotic agent, inducing G2/M phase arrest (51.0%) and restricting MCF-7 wound confluence to 33% at 24 h. In THP-1 macrophages, it maintained low induction of γH2AX-mediated DNA damage signaling. Under alternative M2 pressure, N-CIMZ 1 intercepted polarization by forcing high membrane retention of the immunosuppressive peptide LAP (81%) and suppressing the scavenger marker CD163 (12%) while buffering hyper-reactive CD206+/CD209+ hybrid spikes down to 2.33% under M1 stress. Conclusions: N-CIMZ 1 represents a promising multi-modal scaffold combining antimitotic and macrophage-modulating properties. This targeted immunomodulation effectively subverts tumor-supportive macrophage phenotypes, showcasing the potential of microenvironment reprogramming to counter breast cancer progression and metastasis.