Target Therapy in Cancer Treatment: mPGES-1 and PARP

Target therapy is an approach focusing on specific protein or signaling pathways. This therapy is directly aimed to a molecular target such as a receptor, growth factor or enzyme in cancer cells. These targets are used by the tumor cells themselves to obtain uncontrolled proliferation, resistance to traditional therapies and to increase the number of blood vessels in the tissue of origin (neoangiogenesis). A purpose of target therapy may be to counteract the growth and proliferation of cancer cells through the use of drugs or monoclonal antibodies capable of inhibiting the receptor for the epidermal growth factor (EGFR), that is crucial in the process of neo-angiogenesis, protein kinases (PKs), as regulators of cell growth signals and human epidermal growth factor type 2 (HER2), which is essential in stimulating growth and proliferation of cancer cells. Among anticancer drugs, Bevacizumab, a humanised monoclonal antibody produced by recombinant DNA technique, is used for the first-line treatment of metastatic breast cancer, as it inhibits EGFR and the vascular endothelial cell growth factor (VEGF). Abemaciclib, a protein kinase inhibitor drug, is also used for the treatment of the same cancer. In 20-30% of primary breast tumors, the excessive expression of HER2 is observed; thus, HER2 inhibitors may represent another plausible therapy. A potent HER2 inhibitor is the recombinant humanized igG1 monoclonal antibody Trastuzumab, which was first tested in 1992 and is currently used for the treatment of HER2 positive breast cancer. Unfortunately, despite the numerous advances in finding new therapies, patients treated with these drugs often suffer from severe undesirable side effects. Therefore, the search for new therapeutic targets may be desirable. In this paper we analyse particularly two targets studied quite recently: the microsomal prostaglandin E2 synthase type 1 (mPGES-1) and poly (ADP-ribose) polymerase (PARP) proteins.