Biological Activities and Mechanism of Transition Metal Complexes as Novel Anticancer Agents for Different Cancer Cell Lines—A Review
Transition metal complexes have attracted considerable attention as promising anticancer agents because of their diverse coordination chemistry, tunable structures, and ability to modulate multiple cellular pathways. This review provides a critical overview of the recent advances in transition metal‐based therapeutics, highlighting the relationship between structural design and anticancer activity. The major mechanisms of action, including DNA interaction, reactive oxygen species generation, apoptosis induction, cell cycle arrest, inhibition of angiogenesis, and modulation of key signaling pathways, are discussed to illustrate how these complexes exert their therapeutic effects. Emphasis is placed on structure–activity relationships, examining how the metal center, ligand environment, coordination geometry, oxidation state, and physicochemical properties influence biological performance. Representative complexes of Pt, Zn, Cu, Ni, Au, Fe, Rh, and related transition metals are critically evaluated with respect to their anticancer efficacy and current limitations. Finally, emerging research directions, including rational molecular design, alternative biological targets, computational approaches, advanced characterization, and improved biological evaluation, are discussed to highlight future opportunities for developing safer, more selective, and clinically translatable transition metal‐based anticancer agents.