Metabolic targeted therapy of cancer: current tracer technologies and future drug design strategies in the old metabolic network

Targeted drugs tailored against genes and signaling proteins have formed the new era termed Targeted Therapies. Although the field is relatively young, since only about 5 years ago clinical trials started showing promise, there have are already been significant setbacks due to drug resistance caused by point mutations, alterations in gene expression or complete loss of target proteins with disease progression. Although new drugs are continuously designed and tried, it seems inevitable that genetic and signal protein targets pose too broad flexibility and variability, often changing target characteristics and thus escape treatments turning “magic bullets” into rather “wondering bullets”. This is especially true in cancer, where old and new targeted therapies continue to fail and the most recent ones do not offer much improvement on clinical outcome parameters. Metabolic targeted therapies are aimed at control points of the metabolic network by targeting particular enzymes of major macromolecule synthesis pathways in cancer. This review summarizes the potential benefits of targeted therapies in the metabolic network as applied with genetic and proteomic approaches. The metabolic target approach is most efficient if and when pathway flux information is available for drug target development using the stable isotope based dynamic metabolic profile (SIDMAP) of tumor cells, in vitro or in vivo.