Design, Synthesis, and Biological Evaluation of Novel Aminobisphosphonates Possessing an in Vivo Antitumor Activity Through a γδ-T Lymphocytes-Mediated Activation Mechanism

A small series of aminobisphosphonates (N-BPs) structurally related to zoledronic acid was synthesized with the aim of improving activity toward activation of human γδ T cells and in turn their in vivo antitumor activity. The absence of the 1-OH moiety, together with the position and the different basicity of the nitrogen, appears crucial for antitumor activity. In comparison to zoledronic acid, compound 6a shows a greater ability to activate γδ T cells expression (100 times more) and a proapoptotic effect that is better than zoledronic acid. The potent activation of γδ T cells, in addition to evidence of the in vivo antitumor activity of 6a, suggests it may be a new potential drug candidate for cancer treatment.