NR1 and NR3B Composed Intranuclear N-methyl-d-aspartate Receptor Complexes in Human Melanoma Cells

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Development of redoxprotein-based biohybrid sensor device

We have successfully developed an enzyme electrode based on photosynthetic reaction centre (RC) protein of Rhodobacter sphaeroides purple bacteria. We bound the protein chemically to the electrode surface through a layer of multi-walled carbon nanotubes (MWCNTs). The surface was borosilicate glass covered with indium-tin-oxide (ITO) for its transparency and well-known qualities as an electric semiconductor. We achieved a bio-nanocomposite with good features to support the protein’s photosynthetic activity. To test it, we used the nanocomposite as a working electrode in a traditional electrochemical cell with electrolytes containing only mediators or mediators and inhibitors (herbicides that block the protein’s activity specifically). Our measurements provided great results in terms of electric current (“photocurrent”) generated by the photon-excited RC, regeneration of the electrode surface and stability of the composite. For further optimization of the system, we decided to replace the RC/MWCNT part with a two-component protein complex of chemically bound RC and cytochrome c, which is a natural electron donor of the RC protein. We have successfully prepared the complex and made several measurements to determine the quantity and quality of the product, with good results

PP2B and ERK1/2 regulate hyaluronan synthesis of HT168 and WM35 human melanoma cell lines

Hyaluronan (HA) is the major glycosaminoglycan component of the extracellular matrix in either normal or malignant tissues and it may affect proliferation, motility and differentiation of various cell types. Three isoforms of plasma membrane-bound hyaluronan synthases (HAS 1, 2 and 3) secrete and simultaneously bind pericellular HA. HAS enzymes are subjects of post-translational protein phosphorylation which is believed to regulate their enzymatic activity. In this study, we investigated the HA homeostasis of normal human epidermal melanocytes, HT168 and WM35 human melanoma cell lines and melanoma metastases. HAS2 and HAS3 were detected in all the samples, while the expression of HAS1 was not detectable in any case. Malignant tissue samples and melanoma cell lines contained extra- and intracellular HA abundantly but not normal melanocytes. Applying HA as a chemoattractant facilitated the migration of melanoma cells in Boyden chamber. The amount of HA was reduced upon the inhibition of calcineurin with cyclosporine A (CsA), while the inhibition of ERK1/2 with PD098059 elevated it in both cell lines. The signals of Ser/Thr phosphoproteins at 57 kD were stronger after CsA treatment, while a markedly weaker signal was detected upon inhibition of the MAPK pathway. Our results suggest opposing effects of the two investigated enzymes on the HA homeostasis of melanoma cells. We propose that the dephosphorylation of HAS enzymes targeted by PP2B augments HA production, while their phosphorylation by the activity of MAPK pathway reduces HA synthesis. As the expression of the HA receptor RHAMM was also significantly enhanced by PD098059, the MAPK pathway exerted a complex attenuating effect on HA signalling in the investigated melanoma cells. This observation suggests that the application of MAPK-ERK pathway inhibitors requires a careful therapeutic design in melanoma treatment