In vitro evaluation of antitumoral efficacy of catalase in combination with traditional chemotherapeutic drugs against human lung adenocarcinoma cells.

Lung cancer is the most lethal cancer-related disease worldwide. Since survival rates remain poor, there is an urgent need for more effective therapies that could increase the overall survival of lung cancer patients. Lung tumors exhibit increased levels of oxidative markers with altered levels of antioxidant defenses, and previous studies demonstrated that the overexpression of the antioxidant enzyme catalase (CAT) might control tumor proliferation and aggressiveness. Herein, we evaluated the effect of CAT treatment on the sensitivity of A549 human lung adenocarcinoma cells toward various anticancer treatments, aiming to establish the best drug combination for further therapeutic management of this disease. Exponentially growing A549 cells were treated with CAT alone or in combination with chemotherapeutic drugs (cisplatin, 5-fluorouracil, paclitaxel, daunorubicin, and hydroxyurea). CalcuSyn(®) software was used to assess CAT/drug interactions (synergism or antagonism). Growth inhibition, NFκB activation status, and redox parameters were also evaluated in CAT-treated A549 cells. CAT treatment caused a cytostatic effect, decreased NFκB activation, and modulated the redox parameters evaluated. CAT treatment exhibited a synergistic effect among most of the anticancer drugs tested, which is significantly correlated with an increased H2O2 production. Moreover, CAT combination caused an antagonism in paclitaxel anticancer effect. These data suggest that combining CAT (or CAT analogs) with traditional chemotherapeutic drugs, especially cisplatin, is a promising therapeutic strategy for the treatment of lung cancer.

Evaluation of the neurotoxic/neuroprotective role of organoselenides using differentiated human neuroblastoma SH-SY5Y cell line challenged with 6-hydroxydopamine.

It is well established that oxidative stress plays a major role in several neurodegenerative conditions, like Parkinson disease (PD). Hence, there is an enormous effort for the development of new antioxidants compounds with therapeutic potential for the management of PD, such as synthetic organoselenides molecules. In this study, we selected between nine different synthetic organoselenides the most eligible ones for further neuroprotection assays, using the differentiated human neuroblastoma SH-SY5Y cell line as in vitro model. Neuronal differentiation of exponentially growing human neuroblastoma SH-SY5Y cells was triggered by cultivating cells with DMEM/F12 medium with 1% of fetal bovine serum (FBS) with the combination of 10 µM retinoic acid for 7 days. Differentiated cells were further incubated with different concentrations of nine organoselenides (0.1, 0.3, 3, 10, and 30 µM) for 24 h and cell viability, neurites densities and the immunocontent of neuronal markers were evaluated. Peroxyl radical scavenging potential of each compound was determined with TRAP assay. Three organoselenides tested presented low cytotoxicity and high antioxidant properties. Pre-treatment of cells with those compounds for 24 h lead to a significantly neuroprotection against 6-hydroxydopamine (6-OHDA) toxicity, which were directly related to their antioxidant properties. Neuroprotective activity of all three organoselenides was compared to diphenyl diselenide (PhSe)2, the simplest of the diaryl diselenides tested. Our results demonstrate that differentiated human SH-SY5Y cells are suitable cellular model to evaluate neuroprotective/neurotoxic role of compounds, and support further evaluation of selected organoselenium molecules as potential pharmacological and therapeutic drugs in the treatment of PD.