Multi-target-directed design, syntheses, and characterization of fluorescent bisphosphonate derivatives as multifunctional enzyme inhibitors in mevalonate pathway.

Mevalonate pathway is an important cellular metabolic pathway present in all higher eukaryotes and many bacteria. Four enzymes in mevalonate pathway, including MVK, PMK, MDD, and FPPS, play important regulatory roles in cholesterol biosynthesis and cell proliferation. The following methods were used: cloning, expression and purification of enzymes in mevalonate pathway, organic syntheses of multifunctional enzyme inhibitors, measurement of their IC50 values for above four enzymes, kinetic studies of enzyme inhibitions, molecular modeling studies, cell viability tests, and fluorescence microscopy. We report our multi-target-directed design, syntheses, and characterization of two blue fluorescent bisphosphonate derivatives compounds 15 and 16 as multifunctional enzyme inhibitors in mevalonate pathway. These two compounds had good inhibition to all these four enzymes with their IC50 values at nanomolar to micromolar range. Kinetic and molecular modeling studies showed that these two compounds could bind to the active sites of all these four enzymes. The fluorescence microscopy indicated that these two compounds could easily get into cancer cells. Multifunctional enzyme inhibitors are generally more effective than single enzyme inhibitors, with fewer side effects. Our results showed that these multifunctional inhibitors could become lead compounds for further development for the treatment of soft-tissue tumors and hypercholesteremia.