Differentiation-Dependent Effects of a New Recombinant Manganese Superoxide Dismutase on Human SK-N-BE Neuron-Like Cells (original) (raw)

2018, Neurochemical Research

We have recently isolated a new isoform of recombinant manganese superoxide dismutase (rMnSOD) which provides a potent antitumor activity and strongly counteracts the occurrence of oxidative stress and tissue inflammation. This isoform, in addition to the enzymatic action common to all SODs, also shows special functional and structural properties, essentially due to the presence of a first leader peptide that allows the protein to enter easily into cells. Among endogenous antioxidants, SOD constitutes the first line of natural defence against pathological effects induced by an excess of free radicals. Here, we firstly describe the effects of our rMnSOD administration on the proliferant and malignant undifferentiated human neuroblastoma SK-N-BE cell line. Moreover, we also test the effects of rMnSOD in the all trans retinoic-differentiated SK-N-BE neuron-like cells, a quiescent "not malignant" model. While rMnSOD showed an antitumor activity on proliferating cells, a poor sensitivity to rMnSOD overload in retinoid-differentiated neuron-like cells was observed. However, in the latter case, in presence of experimental-induced oxidative stress, overcharge of rMnSOD enhanced the oxidant effects, through an increase of H 2 O 2 due to low activity of both catalase and glutathione peroxidase. In conclusion, our data show that rMnSOD treatment exerts differential effects, which depend upon both cell differentiation and redox balance, addressing attention to the potential use of the recombinant enzyme on differentiated neurons. These facts ultimately pave the way for further preclinical studies aimed at evaluation of rMnSOD effects in models of neurodegenerative diseases. Keywords Recombinant human manganese superoxide dismutase • Oxidative stress • Free radicals • SK-N-BE • Neurodegeneration Abbreviations ATRA All-trans retinoic acid Aβ Beta-amyloid peptide CAT Catalase Cy Cyanine DHE Dihydroethidium Glu Glutamic acid GSH-px Glutathione peroxidase MQ Menadione quinone MTT 3-[3,4-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide ROS Reactive oxygen species rMnSOD Recombinant manganese superoxide dismutase * Annamaria Confaloni