Quercetin 3,7,3',4'-tetrasulphated isolated from Flaveria bidentis inhibits tissue factor expression in human monocyte

Sulphated esters of the flavonoids sulphated quercetin 3,7,3',4'-tetrasulphated (QTS) and quercetin 3-acetyl-7,3,4'-trisulphate (ATS), isolated from Flaveria bidentis, have demonstrated anticoagulant and antiplatelet properties. In this study, we examined if both compounds affected the expression of the procoagulant tissue factor (TF) induced by lipopolysaccharide (LPS) on human monocyte. Monocytes were pretreated with different concentrations of each flavonoid (0.1-500μM), followed by a 4h incubation with LPS in order to induce TF expression. Results of the TF expression showed different behaviors for the two flavonoids studied. A slight inhibitory effect on the TF expression was detected at a QTS concentration of 0.1μM, but from 1μM onwards a significant inhibitory effect that remained up to 500μM could be observed. In contrast, ATS induced a poor inhibitory effect on TF expression at all concentrations tested. These results suggest that QTS has another antithrombotic property, to be added to its already renowned ability as an anticoagulant and antiplatelet compound.     

Src kinases catalytic activity regulates proliferation, migration and invasiveness of MDA-MB-231 breast cancer cells

SFKs are frequently deregulated in cancer where they control cellular proliferation, migration, survival and metastasis. Here we study the role of SFKs catalytic activity in triple-negative/basal-like and metastatic human breast cancer MDA-MB-231 cells employing three well-established inhibitors: Dasatinib, PP2 and SU6656. These compounds inhibited migration and invasion. Concomitantly, they reduced Fak, paxillin, p130CAS, caveolin-1 phosphorylation and altered cytoskeletal structures. They also inhibited cell proliferation, but in different manners. Dasatinib and PP2 increased p27(Kip1) expression and reduced c-Myc levels, restraining G1–S transition. In contrast, SU6656 did not modify p27(Kip1) expression, slightly altered c-Myc levels and generated polyploid multinucleated cells, indicating inhibition of cytokinesis. These later effects were also observed in SYF fibroblasts, suggesting a SFKs-independent action. ZM447439, an Aurora B kinase inhibitor, produced similar cell cycle and morphological alterations in MDA-MB-231 cells, indicating that SU6656 blocked Aurora B kinase. This was confirmed by inhibition of histone H3 phosphorylation, the canonical Aurora B kinase substrate. Furthermore, hierarchical clustering analysis of gene expression profiles showed that SU6656 defined a set of genes that differed from Dasatinib and PP2. Additionally, Gene Set Enrichment Analyses revealed that SU6656 significantly reduces the Src pathway. Together, these results show the importance of SFKs catalytic activity for MDA-MB-231 proliferation, migration and invasiveness. They also illustrate that SU6656 acts as dual SFKs and Aurora B kinase inhibitor, suggesting its possible use as a therapeutic agent in breast cancer.     

A proteomic profile of washing fluid from the colorectal tract to search for potential biomarkers of colon cancer

Washing fluid (WF) from the colon rectal tract after surgical resection might represent a first step in obtaining a mixture of proteins derived from the secretion of tumoral epithelial cells potentially involved in the pathological progression of tissue. In this study, we performed a proteomic analysis of colorectal WF to search for potential biomarkers of colon cancer. The outcome of this approach might open the possibility of using WF to screen for the precancerous and early stages of colorectal cancer (CRC). Samples of WFs were obtained during surgery from 35 patients submitted to colon resection for suspicious adenocarcinoma or carcinoma, while the respective controls were obtained by washing the healthy sections. WFs were immediately centrifuged, concentrated and trichloroacetic acid (TCA) was added to obtain protein pellets. After two-dimensional gel electrophoresis (2DE), the protein patterns of malignant samples were compared with respective normal samples. Forty-one protein spots were found to be differentially expressed exhibiting ≥2 fold-change of mean value spot intensities. After mass spectrometry, these protein spots collapsed into 38 different proteins. Interestingly, 19 of the differentially expressed proteins identified in the study corresponded to those suggested as being potential biomarkers of CRC. In accordance with the literature, these proteins showed the same direction of change (up or down for all proteins). Our results suggest that WF has the potential of being a method for the exploration of clinical samples for biomarker and drug target discovery.     

An initial investigation of the taxonomic status of Saussurea esthonica Baer ex Rupr. utilising DNA markers and sequencing

Saussurea esthonica Baer ex Rupr. is a species of the genus Saussurea that is found in Estonia, Latvia and the Leningrad region in Russia. Only two populations have been identified in Latvia, and it is protected at the national level. The taxonomic relationships within this genus are unclear, and the majority of phylogenetic studies of this genus have been undertaken on species found in Asia. The relationship of S. esthonica to the other Saussurea species is equally unclear, with some suggestions that this species should be regarded as a subspecies of S. alpina. Two different molecular marker techniques, iPBS and ITS sequencing, were utilised to investigate the phylogeny of S. esthonica and its relationship with other Saussurea species, including three European species: S. alpina, S. pygmaea and S. discolor. The phylogeny obtained with the iPBS markers was similar to that obtained with the ITS sequences. The phylogenies obtained were broadly consistent with previous morphological classification, with S. alpina, S. esthonica and S. discolor clustering together. S. pulchella, S. albescens and S. candicans also formed one discrete cluster. The taxonomic status of S. esthonica was not unambiguously determined, with Norwegian and Italian S. alpina populations clustering with Latvian and Estonian S. esthonica populations, and the Austrian S. alpina populations clustering with Austrian S. discolor populations.     

Hair cells, plasma membrane Ca²⁺ ATPase and deafness

Hearing relies on the ability of the inner ear to convert sound waves into electrical signals. The main actors in this process are hair cells. Their stereocilia contain a number of specific proteins and a scaffold of actin molecules. They are organized in bundles by tip-link filaments composed of cadherin 23 and protocadherin 15. The bundle is deflected by sound waves leading to the opening of mechano-transduction channels and to the influx of K(+) and Ca(2+) into the stereocilia. Cadherin 23 and the plasma membrane calcium ATPase isoform 2 (PMCA2) are defective in human and murine cases of deafness. While the involvement of cadherin 23 in deafness/hearing could be expected due to its structural role in the tip-links, that of PMCA2 has been discovered only recently. This review will summarize the structural and functional characteristics of hair cells, focusing on the proteins whose mutations may lead to a deafness phenotype.