Fisetin Inhibits Human Melanoma Cell Invasion through Promotion of Mesenchymal to Epithelial Transition and by Targeting MAPK and NFκB Signaling Pathways

Malignant melanoma is responsible for approximately 75% of skin cancer-related deaths. BRAF plays an important role in regulating the mitogen-activated protein kinase (MAPK) signaling cascade in melanoma with activating mutations in the serine/threonine kinase BRAF occurring in 60–70% of malignant melanomas. The BRAF-MEK-ERK (MAPK) pathway is a key regulator of melanoma cell invasion. In addition, activation of NFκB via the MAPK pathway is regulated through MEK-induced activation of IKK. These pathways are potential targets for prevention and treatment of melanoma. In this study, we investigated the effect of fisetin, a phytochemical present in fruits and vegetables, on melanoma cell invasion and epithelial-mesenchymal transition, and delineated the underlying molecular mechanism. Treatment of multiple human malignant melanoma cell lines with fisetin (5–20 µM) resulted in inhibition of cell invasion. BRAF mutated melanoma cells were more sensitive to fisetin treatment, and this was associated with a decrease in the phosphorylation of MEK1/2 and ERK1/2. In addition, fisetin inhibited the activation of IKK leading to a reduction in the activation of the NFκB signaling pathway. Treatment of cells with an inhibitor of MEK1/2 (PD98059) or of NFκB (caffeic acid phenethyl ester) also reduced melanoma cell invasion. Furthermore, treatment of fisetin promoted mesenchymal to epithelial transition in melanoma cells, which was associated with a decrease in mesenchymal markers (N-cadherin, vimentin, snail and fibronectin) and an increase in epithelial markers (E-cadherin and desmoglein). Employing three dimensional skin equivalents consisting of A375 cells admixed with normal human keratinocytes embedded onto a collagen-constricted fibroblast matrix, we found that treatment of fisetin reduced the invasive potential of melanoma cells into the dermis and increased the expression of E-cadherin with a concomitant decrease in vimentin. These results indicate that fisetin inhibits melanoma cell invasion through promotion of mesenchymal to epithelial transition and by targeting MAPK and NFκB signaling pathways.     

Cholesterol and its esters as serum biomarkers in malignant obstructive jaundice: a single step 1H NMR metabolomic approach

The paucity of biomarkers for malignant obstructive jaundice results in formidable morbidity and mortality rates. Therefore, alternative diagnostic measures are required for improved clinical interpretation and better peri-operative management of patients. In the present study, ¹H NMR-based metabolomic approach has been applied to investigate serum and bile based metabolic biomarkers in benign and malignant causes of obstructive jaundice (OBJ). Serum and bile specimens from benign OBJ patients (n = 28), malignant OBJ patients (n = 36) and serum of healthy controls (n = 57) were analysed by ¹H NMR spectroscopy. Quantitation of eight serum metabolites (isobutyrate, lactate, alanine, acetone, glutamine, creatine, threonine and 1-methylhistidine) was carried out. A newer and rapid single step NMR based semi-quantitative ratio analysis of serum total cholesterol (tCho), cholesterol (Chol) and cholesterol ester (CE) were performed in deuterated dimethyl sulfoxide-d₆. In bile, total bile acids, cholesterol, phosphatidylcholine, glycerophosphatidylcholine and urea were quantified. The effect of benign and malignant OBJ on small metabolites and lipids were statistically analysed by Mann–Whitney U test and multivariate discriminant function analysis. It was found that malignancy could be differentiated from benign cases of OBJ with a correct classification of 85.7 % when eight serum metabolites in combination with ratios of serum cholesterol were analysed. Significant alterations in serum tCho, Chol, CE and serum metabolites may have potential for early and differential non-invasive diagnosis of malignant and benign OBJ cases. It will further augment the novel insights of local and systemic effects in OBJ patients.     

Deficiency in spliceosome-associated factor CTNNBL1 does not affect ongoing cell cycling but delays exit from quiescence and results in embryonic lethality in mice

CTNNBL1 is an armadillo-repeat protein that associates with the CDC5L/Prp19 complex of the spliceosome. Unlike the majority of spliceosomal proteins (and despite having no obvious homologs), CTNNBL1 is inessential for cell viability as revealed by studies in both vertebrate B cell lines and in fission yeast. Here, however, we show that ablation of CTNNBL1 in the mouse germline results in mid-gestation embryonic lethality but that lineage-specific CTNNBL1 ablation in early B cell precursors does not affect the production and abundance of mature B lymphocytes. However, CTNNBL1-deficient resting B lymphocytes show sluggish exit from quiescence on cell activation, although once entry into cycle has initiated, proliferation and differentiation in response to mitogenic stimuli continue largely unaffected. A similar sluggish exit from quiescence is also observed on reprovision of nutrients to nitrogen-starved CTNNBL1-deficient yeast. The results indicate that, whereas other RNA splicing-associated factors have been connected to cell cycle progression, CTNNBL1 plays no essential role in cycling cells but does fulfill an evolutionarily conserved function in helping cells to undergo efficient exit from quiescence following activation.     

Supervised and Unsupervised Self-Testing for HIV in High- and Low-Risk Populations: A Systematic Review

Background

Stigma, discrimination, lack of privacy, and long waiting times partly explain why six out of ten individuals living with HIV do not access facility-based testing. By circumventing these barriers, self-testing offers potential for more people to know their sero-status. Recent approval of an in-home HIV self test in the US has sparked self-testing initiatives, yet data on acceptability, feasibility, and linkages to care are limited. We systematically reviewed evidence on supervised (self-testing and counselling aided by a health care professional) and unsupervised (performed by self-tester with access to phone/internet counselling) self-testing strategies.

Methods and Findings

Seven databases (Medline [via PubMed], Biosis, PsycINFO, Cinahl, African Medicus, LILACS, and EMBASE) and conference abstracts of six major HIV/sexually transmitted infections conferences were searched from 1st January 2000–30th October 2012. 1,221 citations were identified and 21 studies included for review. Seven studies evaluated an unsupervised strategy and 14 evaluated a supervised strategy. For both strategies, data on acceptability (range: 74%–96%), preference (range: 61%–91%), and partner self-testing (range: 80%–97%) were high. A high specificity (range: 99.8%–100%) was observed for both strategies, while a lower sensitivity was reported in the unsupervised (range: 92.9%–100%; one study) versus supervised (range: 97.4%–97.9%; three studies) strategy. Regarding feasibility of linkage to counselling and care, 96% (n = 102/106) of individuals testing positive for HIV stated they would seek post-test counselling (unsupervised strategy, one study). No extreme adverse events were noted. The majority of data (n = 11,019/12,402 individuals, 89%) were from high-income settings and 71% (n = 15/21) of studies were cross-sectional in design, thus limiting our analysis.

Conclusions

Both supervised and unsupervised testing strategies were highly acceptable, preferred, and more likely to result in partner self-testing. However, no studies evaluated post-test linkage with counselling and treatment outcomes and reporting quality was poor. Thus, controlled trials of high quality from diverse settings are warranted to confirm and extend these findings. Please see later in the article for the Editors'' Summary     

Lipase-catalyzed regioselective protection/deprotection of hydroxyl groups of the isoflavone irilone isolated from Iris germanica

The regioselective acylation of irilone, isolated from Iris germanica, with vinylacetate and propenylacetate and deacylation of irilone diacetate with n-butanol were studied using lipases from Aspergillus niger, Mucor miehei, Pseudomonas cepacia, Candida cylindracea, porcine pancreas and Candida antarctica. Significant conversion of irilone to 4′-O-acetylirilone was achieved using P. cepacia lipase, while irilone diacetate was converted to 5-O-acetylirilone by the enzymatic action of lipases from M. miechei, P. cepacia and porcine pancreas under different experimental conditions. This preferential protection/deprotection furnishes an opportunity to modify the structure of irilone by selective derivatization that may help to change its biological activities by modifying its amphiphilic/lipophilic balance.     

Adenosine deaminase in ischemia reperfusion injury in patients with myocardial infarction

A comparative study on the levels of erythrocyte adenosine deaminase and lipid peroxidation has been undertaken in patients with myocardial infarction before and after thrombolysis along with matched healthy individuals. Our findings show that adenosine deaminase activity is highly elevated in post-reperfused patients when compared to pre- thrombolysed and healthy persons. Malondialdehyde(MDA) levels are also significantly increased in post-thrombolysed patients. The study reveals an important role of adenosine deaminase in reperfusion injury in patients with myocardial infarction.