Anti-tumor withanolides as signal transducers and activators of transcription 3 (STAT3)-inhibition from Withania obtusifolia.

The Solanaceae family and the Withania genus specifically are rich sources of medicinal plants. Liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS/MS) revealed a predominance of withanolides from an organic extract of Withania obtusifolia. A constructed molecular network uncovered the presence of potentially novel withanolides. A series of withanolides were then isolated and structurally characterized from the extract including two new withanolides (withafolia A and withafolia B) and seven previously reported metabolites. Of the isolated compounds, cytotoxicity of withanolide J, physaperuvin G, and a commercial STAT3 inhibitor (S3I-201) were assessed against a human leukemia HL-60 cell line resulting in IC50 values of 26, 29, and 120 µM, respectively. In silico molecular docking simulations indicate that withanolide J and physaperuvin G can bind as an inhibitor in the active site of STAT3 with docking scores comparable to the selective STAT3 inhibitor, S3I-201.

MicroRNA-146b negatively affects bovine embryo development and quality.

MicroRNAs (miRNAs), which can be carried inside extracellular vesicles (EVs), play a crucial role in regulating embryo development up to the blastocyst stage. Yet, the molecular mechanisms underlying blastocyst development and quality are largely unknown. Recently, our group identified 69 differentially expressed miRNAs in extracellular vesicles (EVs) isolated from culture medium conditioned by bovine embryos that either developed to the blastocyst stage or did not (non-blastocysts). We found miR-146b to be more abundant in the EVs derived from media conditioned by non-blastocyst embryos. Using RT-qPCR, we here confirmed the upregulation of miR-146b in non-blastocyst (arrested at 2-4 cell and morula stage) embryos compared to blastocysts (p<0.005), which coincides with the upregulation of miR-146b in EVs derived from the medium of these non-blastocysts. To evaluate a functional effect, bovine embryo culture media were supplemented with miR-146b mimics, resulting in significantly decreased embryo quality, with lower blastocyst rates at day 7 and lower total cell numbers, while the opposite was found after supplementation with miR-146b inhibitors, which resulted in reduced apoptosis rates (P < 0.01). Transcriptomic analysis of embryos treated with miR-146b mimics or inhibitors showed differential expression (P < 0.01) of genes associated with apoptosis, cell differentiation, and the RNA Pol II transcription complex, including WDR36, MBNL2, ERCC6l2, PYGO1, and SNIP1. Overall, miR-146b is overexpressed in non-blastocyst embryos and in EVs secreted by these embryos, and it regulates genes involved in embryo development and apoptosis, resulting in decreased embryo quality.

Hsa-miR-665 Is a Promising Biomarker in Cancer Prognosis.

Biomarkers are biomolecules used to identify or predict the presence of a specific disease or condition. They play an important role in early diagnosis and may be crucial for treatment. MicroRNAs (miRNAs), a group of small non-coding RNAs, are more and more regarded as promising biomarkers for several reasons. Dysregulation of miRNAs has been linked with development of several diseases, including many different types of cancer, and abnormal levels can be present in early stages of tumor development. Because miRNAs are stable molecules secreted and freely circulating in blood and urine, they can be sampled with little or no invasion. Here, we present an overview of the current literature, focusing on the types of cancers for which dysregulation of miR-665 has been associated with disease progression, recurrence, and/or prognosis. It needs to be emphasized that the role of miR-665 sometimes seems ambiguous, in the sense that it can be upregulated in one cancer type and downregulated in another and can even change during the progression of the same cancer. Caution is thus needed before using miR-665 as a biomarker, and extrapolation between different cancer types is not advisable. Moreover, more detailed understanding of the different roles of miR-665 will help in determining its potential as a diagnostic and prognostic biomarker.

Pyrimidine nucleotide synthesis in the emerging pathogen Pseudomonas monteilii.

Regulation of pyrimidine biosynthesis by pyrimidines in the emerging, opportunistic human pathogen Pseudomonas monteilii ATCC 700476 was evident. When wild-type cells were grown on succinate in the presence of uracil or orotic acid, the activities of all 5 pyrimidine biosynthetic enzymes were depressed while the activities of 3 of the enzymes decreased in glucose-grown cells supplemented with uracil or orotic acid compared with unsupplemented cells. Pyrimidine limitation of succinate- or glucose-grown pyrimidine auxotrophic cells lacking orotate phosphoribosyltransferase activity resulted in more than a doubling of the pyrimidine biosynthetic enzyme activities relative to their activities in uracil-grown cells. Independent of carbon source, pyrimidine-limited cells of the pyrimidine auxotrophic cells deficient for dihydroorotase activity generally resulted in a slight elevation or depression of the pyrimidine biosynthetic enzyme activities compared with their activities in cells grown under saturating uracil conditions. Aspartate transcarbamoylase activity in P. monteilii was regulated at the enzyme activity level, since the enzyme was strongly inhibited by CTP, UMP, GMP, GDP, ADP, and UTP. In summary, the regulation of pyrimidine biosynthesis in P. monteilii could be used to control its growth or to differentiate it biochemically from other related species of Pseudomonas.