Vitamin B6 is a fascinating molecule involved in the vast majority of changes in the human body because it is a coenzyme involved in over 150 biochemical reactions. It is active in the metabolism of carbohydrates, lipids, amino acids, and nucleic acids, and participates in cellular signaling. It is an antioxidant and a compound with the ability to lower the advanced glycation end products (AGE) level. In this review, we briefly summarize its involvement in biochemical pathways and consider whether its deficiency may be associated with various diseases such as diabetes, heart disease, cancer, or the prognosis of COVID-19.

The patho-mechanism of changes in the thyroid gland, including carcinogenesis, is a complex process, which involves oxidative stress. The goal of our investigation was to verify the extent of stress in the thyroid gland related to glycation. The study samples were comprised of blood sera, thyroid, and adipose tissue sections probed from 37 patients diagnosed with thyroid cancers and goiter. Using immuno-enzymatic and fluorometric assays we analyzed the content of advanced glycation end-products (AGEs), pentosidine, receptors for advanced glycation end-products (RAGE), scavenger receptor class (SR)-A, SR-B, glutathione, malondialdehyde and nitric oxide synthase. In addition to classic AGEs, a recent study detected the melibiose-derived glycation (MAGE) product. We demonstrated the presence of AGEs, MAGE and their receptors of the RAGE and SR-A. In addition, in the control samples of thyroid glands SR-B groups were detected as well as of pathological groups without noticeable tendency to antigen concentration in the area of carcinogenesis. Fluorescent AGEs correlate positively with glutathione, which supports the assumption that glycation stress leads to augmentation of oxidative stress and increase of the intensity of antioxidant mechanisms.

Inhibition of the protein neddylation process by the small-molecule inhibitor MLN4924 has been recently indicated as a promising direction for cancer treatment. However, the knowledge of all biological consequences of MLN4924 for cancer cells is still incomplete. Here, we report that MLN4924 inhibits tumor necrosis factor-alpha (TNF-α)-induced matrix metalloproteinase 9 (MMP9)-driven cell migration. Using real-time polymerase chain reaction (PCR) and gelatin zymography, we found that MLN4924 inhibited expression and activity of MMP9 at the messenger RNA (mRNA) and protein levels in both resting cells and cells stimulated with TNF-α, and this inhibition was closely related to impaired cell migration. We also revealed that MLN4924, similar to TNF-α, induced phosphorylation of inhibitor of nuclear factor kappa B-alpha (IκB-α). However, contrary to TNF-α, MLN4924 did not induce IκB-α degradation in treated cells. In coimmunoprecipitation experiments, nuclear IκB-α which formed complexes with nuclear factor kappa B p65 subunit (NFκB/p65) was found to be highly phosphorylated at Ser32 in the cells treated with MLN4924, but not in the cells treated with TNF-α alone. Moreover, in the presence of MLN4924, nuclear NFκB/p65 complexes were found to be enriched in c-Jun and cyclin dependent kinase inhibitor 1 A (CDKN1A/p21) proteins. In these cells, NFκB/p65 was unable to bind to the MMP9 gene promoter, which was confirmed by the chromatin immunoprecipitation (ChIP) assay. Taken together, our findings identified MLN4924 as a suppressor of TNF-α-induced MMP9-driven cell migration in esophageal squamous cell carcinoma (ESCC), likely acting by affecting the nuclear ubiquitin–proteasome system that governs NFκB/p65 complex formation and its DNA binding activity in regard to the MMP9 promoter, suggesting that inhibition of neddylation might be a new therapeutic strategy to prevent invasion/metastasis in ESCC patients.