In Vivo Anticancer Activity of a Nontoxic Inert Phenolato Titanium Complex: High Efficacy on Solid Tumors Alone and Combined with Platinum Drugs

Due to the toxicity of platinum compounds used in the clinic as anticancer chemotherapies, titanium serves as a safe and attractive alternative. Lately, we introduced a new family of Ti complexes based on readily available phenolato ligands, demonstrating incredibly high hydrolytic stability, with the lead compound phenolaTi demonstrating wide cytotoxic activity toward the NCI-60 panel of human cancer cell lines, with an average GI₅₀ value of 4.7±2 μm. Herein, we evaluated in vivo: a) the safety, and b) the growth inhibitory capacity (efficacy) of this compound. PhenolaTi was found to be effective in vivo against colon (CT-26) and lung (LLC-1) murine cell lines in syngeneic hosts and toward a human colon cancer (HT-29) cell line in immune-deficient (Nude) mice, with an efficacy similar to that of known chemotherapy. Notably, no clinical signs of toxicity were observed in the treated mice, namely, no effect on body weight, spleen weight or kidney function, unlike the effects observed with the positive control Pt drugs. Studies of combinations of phenolaTi and Pt drugs provided evidence that similar efficacy with decreased toxicity may be achieved, which is highly valuable for medicinal applications.