Effects of silencing of cytosolic 5’-nucleotidase II (cN-II) on cancer cell lines

Cytosolic 5’-nucleotidase II (cN-II) is an IMP/GMP preferring 5’-nucleotidase whose activity, structure and expression has drawn the attention of several research groups from various fields such as biochemistry, crystallography, molecular biology, oncology, pharmacology and genetics. Despite a good knowledge of its tissue distribution, structure, catalytic features, allosteric regulation and possible physiological roles, cN-II still remains a clue in how it could influence cellular vital functions. In this PhD project we investigated the role of this enzyme on nucleotide content, mitochondrial mass, mitochondrial reactive oxygen species (ROS) and mitochondrial membrane potential, protein synthesis and autophagy, migration and proliferative capacity, modulation of immune cell cytotoxicity. We utilized three human cancer cell lines: lung carcinoma cells A549, glioblastoma cells ADF, triple negative breast cancer cells MDA-MB-231. In order to evaluate the role of cN-II, the expression of this enzyme was stably decreased. In A549 and ADF cells the transfection with cN-II targeting shRNA decreased the expression about 50%. In MDA-MB-231 the cN-II expression was completely abolished by using CRISPR/Cas9 technique. Our results demonstrate that high cN-II expression is associated with a glycolytic, highly proliferating phenotype, while silencing causes a reduction of proliferation, protein synthesis and migration ability, and an increase of oxidative performances. Moreover, we demonstrate that cN-II silencing is concomitant with p53 phosphorylation, suggesting a possible involvement of this pathway in mediating some of cN-II roles in cancer cell biology