The transcription factor c-Myb is an oncoprotein promoting cell proliferation and survival when aberrantly activated/expressed, thus contributing to malignant transformation. Overexpression of c-Myb has been found in leukemias, breast, colon and adenoid cystic carcinoma. Recent studies revealed its expression also in osteosarcoma cell lines and suggested its functional importance during bone development. However, the relevance of c-Myb in control of osteosarcoma progression remains unknown. A retrospective clinical study was carried out to assess a relationship between c-Myb expression in archival osteosarcoma tissues and prognosis in a cohort of high-grade osteosarcoma patients. In addition, MYB was depleted in metastatic osteosarcoma cell lines SAOS-2 LM5 and 143B and their growth, chemosensitivity, migration and metastatic activity were determined. Immunohistochemical analysis revealed that high c-Myb expression was significantly associated with poor overall survival in the cohort and metastatic progression in young patients. Increased level of c-Myb was detected in metastatic osteosarcoma cell lines and its depletion suppressed their growth, colony-forming capacity, migration and chemoresistance in vitro in a cell line-dependent manner. MYB knock-out resulted in reduced metastatic activity of both SAOS-2 LM5 and 143B cell lines in immunodeficient mice. Transcriptomic analysis revealed the c-Myb-driven functional programs enriched for genes involved in the regulation of cell growth, stress response, cell adhesion and cell differentiation/morphogenesis. Wnt signaling pathway was identified as c-Myb target in osteosarcoma cells. Taken together, we identified c-Myb as a negative prognostic factor in osteosarcoma and showed its involvement in the regulation of osteosarcoma cell growth, chemosensitivity, migration and metastatic activity.

• Keywords
• Chemoresistance, Metastasis, Osteosarcoma, Prognosis, Proliferation, c-Myb,
• MeSH
• Humans MeSH
• Mice MeSH
• Cell Line, Tumor MeSH
• Bone Neoplasms * pathology   MeSH
• Osteosarcoma * pathology   MeSH
• Cell Movement genetics   MeSH
• Prognosis MeSH
• Cell Proliferation MeSH
• Gene Expression Regulation, Neoplastic MeSH
• Retrospective Studies MeSH
• Wnt Signaling Pathway MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Neurodegenerative disorders present a broad group of neurological diseases and remain one of the greatest challenges and burdens to mankind. Maladies like amyotrophic lateral sclerosis, Alzheimer's disease, stroke or spinal cord injury commonly features astroglia involvement (astrogliosis) with signs of inflammation. Regenerative, paracrine and immunomodulatory properties of human mesenchymal stromal cells (hMSCs) could target the above components, thus opening new therapeutic possibilities for regenerative medicine. A special interest should be given to hMSCs derived from the umbilical cord (UC) tissue, due to their origin, properties and lack of ethical paradigms. The aim of this study was to establish standard operating and scale-up good manufacturing practice (GMP) protocols of UC-hMSCs isolation, characterization, expansion and comparison of cells' properties when harvested on T-flasks versus using a large-scale bioreactor system. Human UC-hMSCs, isolated by tissue explant culture technique from Wharton's jelly, were harvested after reaching 75% confluence and cultured using tissue culture flasks. Obtained UC-hMSCs prior/after the cryopreservation and after harvesting in a bioreactor, were fully characterized for "mesenchymness" immunomodulatory, tumorigenicity and genetic stability, senescence and cell-doubling properties, as well as gene expression features. Our study demonstrates an efficient and simple technique for large scale UC-hMSCs expansion. Harvesting of UC-hMSCs' using classic and large scale methods did not alter UC-hMSCs' senescence, genetic stability or in vitro tumorigenicity features. We observed comparable growth and immunomodulatory capacities of fresh, frozen and expanded UC-hMSCs. We found no difference in the ability to differentiate toward adipogenic, osteogenic and chondrogenic lineages between classic and large scale UC-hMSCs expansion methods. Both, methods enabled derivation of genetically stabile cells with typical mesenchymal features. Interestingly, we found significantly increased mRNA expression levels of neural growth factor (NGF) and downregulated insulin growth factor (IGF) in UC-hMSCs cultured in bioreactor, while IL4, IL6, IL8, TGFb and VEGF expression levels remained at the similar levels. A culturing of UC-hMSCs using a large-scale automated closed bioreactor expansion system under the GMP conditions does not alter basic "mesenchymal" features and quality of the cells. Our study has been designed to pave a road toward translation of basic research data known about human UC-MSCs for the future clinical testing in patients with neurological and immunocompromised disorders. An industrial manufacturing of UC-hMSCs next will undergo regulatory approval following advanced therapy medicinal products (ATMP) criteria prior to clinical application and approval to be used in patients.

• Keywords
• Bioreactor, Good manufacturing practice (GMP), Large-scale expansion, Mesenchymal stromal cells, Umbilical cord tissue,
• MeSH
• Bioreactors * MeSH
• Cells, Cultured MeSH
• Humans MeSH
• Mesenchymal Stem Cells physiology   MeSH
• Nervous System Diseases pathology   therapy   MeSH
• Cell Proliferation physiology   MeSH
• Umbilical Cord cytology   physiology   transplantation   MeSH
• Mesenchymal Stem Cell Transplantation * trends   MeSH
• Wharton Jelly cytology   physiology   transplantation   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

Wedelolactone is a multi-target natural plant coumestan exhibiting cytotoxicity towards cancer cells. Although several molecular targets of wedelolactone have been recognized, the molecular mechanism of its cytotoxicity has not yet been elucidated. In this study, we show that wedelolactone acts as an inhibitor of chymotrypsin-like, trypsin-like, and caspase-like activities of proteasome in breast cancer cells. The proteasome inhibitory effect of wedelolactone was documented by (i) reduced cleavage of fluorogenic proteasome substrates; (ii) accumulation of polyubiquitinated proteins and proteins with rapid turnover in tumor cells; and (iii) molecular docking of wedelolactone into the active sites of proteasome catalytic subunits. Inhibition of proteasome by wedelolactone was independent on its ability to induce reactive oxygen species production by redox cycling with copper ions, suggesting that wedelolactone acts as copper-independent proteasome inhibitor. We conclude that the cytotoxicity of wedelolactone to breast cancer cells is partially mediated by targeting proteasomal protein degradation pathway. Understanding the structural basis for inhibitory mode of wedelolactone might help to open up new avenues for design of novel compounds efficiently inhibiting cancer cells.

• Keywords
• breast cancer, copper, proteasome, reactive oxygen species, wedelolactone,
• MeSH
• Proteasome Inhibitors chemistry   pharmacology   toxicity   MeSH
• Coumarins chemistry   pharmacology   toxicity   MeSH
• Humans MeSH
• Copper metabolism   MeSH
• Cell Line, Tumor MeSH
• Breast Neoplasms metabolism   MeSH
• Proteasome Endopeptidase Complex chemistry   metabolism   MeSH
• Proteolysis MeSH
• Reactive Oxygen Species metabolism   MeSH
• Molecular Docking Simulation MeSH
• Ubiquitination MeSH
• Protein Binding MeSH
• Cell Survival drug effects   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Proteasome Inhibitors MeSH
• Coumarins MeSH
• Copper MeSH
• Proteasome Endopeptidase Complex MeSH
• Reactive Oxygen Species MeSH
• wedelolactone MeSH Browser