The therapeutic potential of gallium-based complexes in anti-tumor drug design

The investigation of metal-containing drugs over several decades has set out to improve upon the toxicity and efficacy of conventional chemotherapeutic agents. Promising pre-clinical and clinical data have fostered the broadening for the search of metal compounds in cancer treatment and combination therapy. Gallium is only second to platinum in terms of anti-tumor activity. Its subsequent investigation has been ongoing for nearly three decades, primarily in the form of salts, and more recently coordinated to organic ligands as coordination complexes. From its early investigation as a diagnostic agent to its anti-tumor potential, promising clinical results have shown a renewed interest in exploring gallium in a host of malignancies, especially lymphoma and bladder cancer. However, the detailed mechanisms of action of gallium compounds are not completely defined. Further understanding the underlying mechanisms along with optimizing the structural components of gallium complexes will further improve the therapeutic index of gallium.