Pieces of the complex puzzle of cancer cell energy metabolism: an overview of energy metabolism and alternatives for targeted cancer therapy.

Over the past decades, several advances in cancer cell biology have led to relevant details about a phenomenon called "Warburg effect". Currently, it has been accepted that Warburg effect is not anymore compatible with all cancer cells, and thus the process of aerobic glycolysis is now challenged by the knowledge of a large number of cells presenting mitochondrial function. The energy metabolism of cancer cells is focused in the bioenergetic and biosynthetic pathways to meet the requirements of rapid proliferation. Changes in the metabolism of carbohydrate, amino acids and lipids have already been reported in cancer cells and might play relevant roles for cancer progression. To the best of our knowledge, mostly of these changes are established, mainly due to genetic reprogramming that leads to the transformation of a healthy into a cancerous cell. Indeed, several enzymes of high relevance for the energy are targets of oncogenes (ex. PI3K, HIF1 and Myc) and tumor suppressor proteins (ex. p53). As a consequence of the extensive study on cancer cell metabolism, some new therapeutic strategies have appeared that aim to interrupt the aberrant metabolism, as well as the influence of genetic reprogramming in cancer cells. In this perspective, we briefly review the cancer cell metabolism (carbohydrate, amino acid and lipid), and also describe oncogenes and tumor suppressors that affect cancer cell metabolism. We also discuss some potential candidates for target therapy to disrupt the main driven-force for cancer cell metabolism and proliferation.