Effects on Energy Metabolism of Two Guanidine Molecules, (Boc)2-Creatine and Metformin

Several enzymes are involved in the energy production, becoming a possible target for new anti-cancer drugs. In this paper, we used biochemical and in silico studies to evaluate the effects of two guanidine molecules, (Boc)2-creatine and metformin, on creatine kinase, an enzyme involved in the regulation of intracellular energy levels. Our results show that both drugs inhibit creatine kinase activity; however, (Boc)2-creatine displays a competitive inhibition, while metformin acts with a non-competitive mechanism. Moreover, (Boc)2-creatine is able to inhibit the activity of hexokinase with a non-competitive mechanism. Considering that creatine kinase and hexokinase are involved in energy metabolism, we evaluated the effects of (Boc)2-creatine and metformin on the ATP/AMP ratio and on cellular proliferation in healthy fibroblasts, human breast cancer cells (MDA-MB-468), a human neuroblastoma cell line (SH-SY5Y), a human Hodgkin lymphoma cell line (KMH2). We found that healthy fibroblasts were only partially affected by (Boc)2-creatine, while both ATP/AMP ratio and viability of the three cancer cell lines were significantly decreased. By inhibiting both creatine kinase and hexokinase, (Boc)2-creatine appears as a promising new agent in anticancer treatment. Further research is needed to understand what types of cancer cells are most suitable to treatment by this new compound.