Figure 1.

Polyamines imbalance in tumors: an intriguing Achilles heel to fight cancer. (a) Rapidly growing cancer cells have higher contents of intracellular polyamines compared to normal, healthy tissues. Amine oxidases, the enzymes designated to control polyamines levels in cells, catalyze the oxidative deamination of polyamines leading to the formation of cytotoxic products, i.e., H₂O₂, and aldehydes. Exploiting different nano-based delivery strategies, bovine serum amine oxidase (BSAO) has been used to kill tumor cells. In the cartoon, two different BSAO smart nano-vehicles are depicted: (b) SAMN@RITC-BSAO, in which the enzyme was immobilized on the surface of magnetic iron oxide nanoparticles through a fluorescent spacer arm [47]; (c) Au@pDMPA/HCl-BSAO, a core–shell gold nanoparticles stabilized with the hydrophilic polymer (poly(3-dimethylammonium-1-propyne hydrochloride) and decorated with BSAO as described in the main text [45].