Microfluidic enrichment, isolation and characterization of disseminated melanoma cells from lymph node samples.

For the first time in melanoma, novel therapies have recently shown efficacy in the adjuvant therapy setting, which makes companion diagnostics to guide treatment decisions a desideratum. Early spread of disseminated cancer cells (DCC) to sentinel lymph nodes (SLN) is indicative of poor prognosis in melanoma and early DCCs could therefore provide important information about the malignant seed. Here, we present a strategy for enrichment of DCCs from SLN suspensions using a microfluidic device (Parsortix™, Angle plc). This approach enables the detection and isolation of viable DCCs, followed by molecular analysis and identification of genetic changes. By optimizing the workflow, the established protocol allows a high recovery of DCC from melanoma patient-derived lymph node (LN) suspensions with harvest rates above 60%. We then assessed the integrity of the transcriptome and genome of individual, isolated DCCs. In LNs of melanoma patients, we detected the expression of melanoma-associated transcripts including MLANA (encoding for MelanA protein), analyzed the BRAF and NRAS mutational status and confirmed the malignant origin of isolated melanoma DCCs by comparative genomic hybridization. We demonstrate the feasibility of epitope-independent isolation of LN DCCs using Parsortix™ for subsequent molecular characterization of isolated single DCCs with ample application fields including the use for companion diagnostics or subsequent cellular studies in personalized medicine.

Class I histone deacetylases regulate p53/NF-κB crosstalk in cancer cells.

The transcription factors NF-κB and p53 as well as their crosstalk determine the fate of tumor cells upon therapeutic interventions. Replicative stress and cytokines promote signaling cascades that lead to the co-regulation of p53 and NF-κB. Consequently, nuclear p53/NF-κB signaling complexes activate NF-κB-dependent survival genes. The 18 histone deacetylases (HDACs) are epigenetic modulators that fall into four classes (I-IV). Inhibitors of histone deacetylases (HDACi) become increasingly appreciated as anti-cancer agents. Based on their effects on p53 and NF-κB, we addressed whether clinically relevant HDACi affect the NF-κB/p53 crosstalk. The chemotherapeutics hydroxyurea, etoposide, and fludarabine halt cell cycle progression, induce DNA damage, and lead to DNA fragmentation. These agents co-induce p53 and NF-κB-dependent gene expression in cell lines from breast and colon cancer and in primary chronic lymphatic leukemia (CLL) cells. Using specific HDACi, we find that the class I subgroup of HDACs, but not the class IIb deacetylase HDAC6, are required for the hydroxyurea-induced crosstalk between p53 and NF-κB. HDACi decrease the basal and stress-induced expression of p53 and block NF-κB-regulated gene expression. We further show that class I HDACi induce senescence in pancreatic cancer cells with mutant p53.

Metabolic implications of menstrual cycle length in non-hyperandrogenic women with polycystic ovarian morphology.

This cross-sectional study aimed to investigate the association between menstrual cycle lenght and metabolic parameters in non-hyperandrogenic women with polycystic ovarian morphology, n = 250. Metabolic profiles of all participants were evaluated using anthropometric parameters (body mass index, waist circumference), parameters of dyslipidemia (total cholesterol, HDL-cholesterol, triglycerides) and markers of insulin resistance (fasting insulin, homeostasis model assessment for insulin resistance index). The associations between menstrual cycle lenght and cardiometabolic risk factors such as insulin resistance, dyslipidemia, and obesity were investigated. In non-hyperandrogenic women with polycystic ovarian morphology, menstrual cycle lenght was associated with hypertriglyceridemia and insulin resistance independently of body mass index. Moreover, menstrual cycle lenght added value to body mass index in predicting hypertriglyceridemia. The optimal menstrual cycle lenght cut-off value for identifying of non-hyperandrogenic women with polycystic ovarian morphology at metabolic risk was found to be 45 days. Metabolic profile of non-hyperandrogenic women with polycystic ovarian morphology (n = 75) with menstrual cycle lenght >45 days was similar to that of hyperandrogenic women with polycystic ovarian morphology (n = 138) while metabolic profile of non-hyperandrogenic women with polycystic ovarian morphology with menstrual cycle lenght ≤45 days (n = 112) was similar to that of controls (n = 167). Non-hyperandrogenic women with polycystic ovarian morphology with menstrual cycle lenght >45 days had higher prevalence of cardiometabolic risk factors compared to those with menstrual cycle lenght ≤45 days. Non-hyperandrogenic women with polycystic ovarian morphology are not metabolically homogeneous. Menstrual cycle lenght is an easy-to-obtain clinical parameter positively associated with the probability of unfavorable metabolic status in non-hyperandrogenic women with polycystic ovarian morphology. Menstrual cycle lenght cut-off value of 45 days was found to have the best capacity in discriminating non-hyperandrogenic women with polycystic ovarian morphology with and without metabolic derangement(s) corroborating in favor of the cardiometabolic risk factors screening and management in non-hyperandrogenic women with polycystic ovarian morphology with menstrual cycle lenght >45 days through strategies for prevention of cardiovascular disease.

MYC and EGR1 synergize to trigger tumor cell death by controlling NOXA and BIM transcription upon treatment with the proteasome inhibitor bortezomib.

The c-MYC (MYC afterward) oncogene is well known for driving numerous oncogenic programs. However, MYC can also induce apoptosis and this function of MYC warrants further clarification. We report here that a clinically relevant proteasome inhibitor significantly increases MYC protein levels and that endogenous MYC is necessary for the induction of apoptosis. This kind of MYC-induced cell death is mediated by enhanced expression of the pro-apoptotic BCL2 family members NOXA and BIM. Quantitative promoter-scanning chromatin immunoprecipitations (qChIP) further revealed binding of MYC to the promoters of NOXA and BIM upon proteasome inhibition, correlating with increased transcription. Both promoters are further characterized by the presence of tri-methylated lysine 4 of histone H3, marking active chromatin. We provide evidence that in our apoptosis models cell death occurs independently of p53 or ARF. Furthermore, we demonstrate that recruitment of MYC to the NOXA as well as to the BIM gene promoters depends on MYC's interaction with the zinc finger transcription factor EGR1 and an EGR1-binding site in both promoters. Our study uncovers a novel molecular mechanism by showing that the functional cooperation of MYC with EGR1 is required for bortezomib-induced cell death. This observation may be important for novel therapeutic strategies engaging the inherent pro-death function of MYC.

Definition of insulin resistance using the homeostasis model assessment (HOMA-IR) in IVF patients diagnosed with polycystic ovary syndrome (PCOS) according to the Rotterdam criteria.

Polycystic ovary syndrome (PCOS) women are more insulin resistant than general population. Prevalence data on insulin resistance (IR) in PCOS vary depending on population characteristics and methodology used. The objectives of this study were to investigate whether IR in PCOS is exclusively associated with body mass and to assess the prevalence of IR in lean and overweight/obese PCOS. Study included 250 consecutive women who attended a Department of Human Reproduction diagnosed as having PCOS according to the Rotterdam criteria. Control group comprised 500 healthy women referred for male factor infertility evaluation during the same period as the PCOS women. PCOS women (n = 250) were more insulin resistant than controls (n = 500) even after adjustment for age and body mass index (BMI) (P = 0.03). Using logistic regression analysis, BMI ≥ 25 kg/m(2) (OR 6.0; 95 % CI 3.3-11.0), PCOS (OR 2.2; 95 % CI 1.4-3.5) and waist circumference ≥ 80 cm (OR 2.0; 95 % CI 1.1-3.8) were identified as independent determinants of IR (P < 0.001). IR was more prevalent in overweight/obese controls (n = 100) than in lean PCOS women (n = 150), 31 versus 9.3 %, but less prevalent than in overweight/obese PCOS (n = 100), 31 versus 57 %. The prevalence of IR between lean controls (5 %) and lean PCOS (9.3 %) did not significantly differ. Both PCOS-specific and obesity-related IR independently contribute to IR in PCOS. Using HOMA-IR cutoff value of 3.15 specific for Croatian women in our clinical setting, the assessed prevalence of IR in lean and overweight/obese PCOS women was 9.3 and 57 %, respectively.

Dehydroepiandrostendione sulphate and prediction of live birth after IVF in young women with low anti-Müllerian hormone concentration.

Baseline dehydroepiandrostendione sulphate (DHEAS) has been demonstrated to discriminate between young, expected poor responders with favourable clinical pregnancy prospects after IVF treatment and their counterparts with significantly lower pregnancy chances. This study investigated DHEAS ability to predict live birth before starting the first gonadotrophin-releasing hormone (GnRH) antagonist ovarian stimulation for IVF/intracytoplasmic sperm injection in young women (⩽37years) with low serum AMH (<6.5pmol/l). Medical records of 90patients were analysed. DHEAS was predictive for live birth (AUC-ROC 0.69, 95% CI 0.59-0.79). Its predictive accuracy for live birth was similar to that of the number of oocytes retrieved. The cut-off value for DHEAS of 5.4µmol/l offered the best discriminative performance between patients who achieved live birth and those who did not. The live birth rate per initiated cycle in women with DHEAS concentration >5.4µmol/l was 5-fold higher compared with women with DHEAS ⩽5.4µmol/l (38.9% versus 7.4%, P<0.001) despite similar oocyte yield in both groups. In conclusion, the association between baseline DHEAS and probability of live birth after the GnRH antagonist IVF cycle in young women with low AMH was demonstrated. This association could not be explained by the effect of DHEAS on the oocyte yield. This study demonstrates an association of baseline dehydroepinadrostendione sulphate (DHEAS) concentration with implantation rate and live birth rate after the first gonadotrophin-releasing hormone antagonist IVF cycle in young women who are expected to respond poorly to ovarian stimulation. Compared with the number of oocytes retrieved, DHEAS showed a similar ability to distinguish women who will achieve a live birth from those who will not. However, as a parameter available to clinicians and patients before commencing an ovarian stimulation for IVF, DHEAS could be used in predicting probability of live birth at the initial consultation. Women whose DHEAS concentrations were above the derived cut-off value 5.4µmol/l had 5-fold more favourable prognosis for live birth than their counterparts with DHEAS concentrations below the cut-off value. The findings could not be explained by the difference in the oocyte yield and/or the number of embryos transferred but rather by the possible association between the endogenous DHEAS concentration and the oocyte competence to produce a viable embryo.

The IVF Outcome Counseling Based on the Model Combining DHEAS and Age in Patients with Low AMH Prior to the First Cycle of GnRH Antagonist Protocol of Ovarian Stimulation.

Objective. To investigate the endocrine and/or clinical characteristics of women with low anti-Müllerian hormone (AMH) that could improve the accuracy of IVF outcome prediction based on the female age alone prior to the first GnRH antagonist IVF cycle. Methods. Medical records of 129 patients with low AMH level (<6.5 pmol/L) who underwent their first GnRH antagonist ovarian stimulation protocol for IVF/ICSI were retrospectively analyzed. The main outcome measure was the area under the ROC curve (AUC-ROC) for the models combining age and other potential predictive factors for the clinical pregnancy. Results. Clinical pregnancy rate (CPR) per initiated cycles was 11.6%. For the prediction of clinical pregnancy, DHEAS and age showed AUC-ROC of 0.726 (95%CI 0.641-0.801) and 0.662 (95%CI 0.573-0.743), respectively (P = 0.522). The predictive accuracy of the model combining age and DHEAS (AUC-ROC 0.796; 95%CI 0.716-0.862) was significantly higher compared to that of age alone (P = 0.013). In patients <37.5 years with DHEAS >5.7 pmol/L, 60% (9/15) of all pregnancies were achieved with CPR of 37.5%. Conclusions. DHEAS appears to be predictive for clinical pregnancy in younger women (<37.5 years) with low AMH after the first GnRH antagonist IVF cycle. Therefore, DHEAS-age model could refine the pretreatment counseling on pregnancy prospects following IVF.

MYC directs transcription of MCL1 and eIF4E genes to control sensitivity of gastric cancer cells toward HDAC inhibitors.

Histone deacetylases (HDACs) control fundamental physiological processes such as proliferation and differentiation. HDAC inhibitors (HDACi) induce cell cycle arrest and apoptosis of tumor cells. Therefore, they represent promising cancer therapeutics that appear particularly useful in combination therapies. Although HDACi are tested in current clinical trials, the molecular mechanisms modulating the cellular responses toward HDACi are incompletely understood. To gain insight into pathways that limit HDACi efficacy in gastric cancer, we treated a panel of gastric cancer cells with the clinically relevant HDACi suberoylanilide hydroxamic acid (SAHA). We report that higher expression levels of the anti-apoptotic BCL2 family members MCL1 and BCL(XL) were detectable in cells with high inhibitory concentration 50 (IC(50)) values for SAHA. Using RNAi, we show that MCL1 and BCL(XL) lower the efficacy of SAHA. To find strategies to interfere with MCL1 and BCL(XL) expression, we investigated molecular regulation of both proteins. We show that specific siRNAs against c-MYC as well as pharmacological inhibition of this cancer-relevant transcription factor reduced MCL1 and BCL(XL) expression. Subsequently, we observed an increase in SAHA efficacy. Our data furthermore demonstrate that two different molecular mechanisms are responsible for the modulation of these factors. Whereas c-MYC controls transcription of MCL1 directly, regulation of BCL(XL) was due to c-MYC's capability to regulate the eIF4E gene, which encodes a rate-limiting factor of eukaryotic translation. Our data reveal a new molecular mechanism for how c-MYC controls cell autonomous apoptosis and provide a rationale for a concerted inhibition of HDACs and c-MYC in gastric cancer.

A simple and cost-effective method to transfect small interfering RNAs into pancreatic cancer cell lines using polyethylenimine.

OBJECTIVES: RNA interference, an indispensable tool in functional genomics, can be induced by small interfering RNAs (siRNAs). Because of the transient nature of siRNA-mediated RNA interference, the continuous use of transfection reagents is mandatory. Because transfection reagents are expensive, cost-effective alternatives must be considered. In this study, we describe a polyethylenimine-based siRNA transfection protocol for pancreatic cancer cell lines. METHODS: For determination of polyethylenimine-based transfection efficiency, a FAM-labeled siRNA was transfected into several pancreatic cancer cell lines and subsequently analyzed by flow cytometry. The effective knockdown of 2 siRNAs was determined on the protein level by Western blot. Toxicity of the transfection reagent was analyzed by viability assays. RESULTS: Polyethylenimine can be used without overt cellular morphological changes, and toxicity is negligible in human and murine pancreatic cancer cell lines. Transfection efficiencies ranged between 83% and 98% in the cell lines used. The knockdown at the protein level was comparable to commercially available transfection reagents. Polyethylenimine and siRNA concentrations, incubation time, and cell density are determinates of the transfection efficiency. CONCLUSIONS: Polyethylenimine is a suitable and cost-effective alternative for transfecting siRNAs into pancreatic cancer cells.

Fluorescence-based comparative binding studies of the supramolecular host properties of PAMAM dendrimers using anilinonaphthalene sulfonates: unusual host-dependent fluorescence titration behavior.

This work describes the fluorescence enhancement of the anilinonaphthalene sulfonate probes 1,8-ANS, 2,6-ANS, and 2,6-TNS via complexation with PAMAM dendrimer hosts of Generation 4, 5 and 6. The use of this set of three very closely related probes allows for comparative binding studies, with specific pairs of probes differing only in shape (1,8-ANS and 2,6-ANS), or in the presence of a methyl substituent (2,6-TNS vs. 2,6-ANS). The fluorescence of all three probes was significantly enhanced upon binding with PAMAM dendrimers, however in all cases except one, a very unusual spike was consistently observed in the host fluorescence titration plots (fluorescence enhancement vs. host concentration) at low dendrimer concentration. This unprecedented fluorescence titration curve shape makes fitting the data to a simple model such as 1:1 or 2:1 host: guest complexation very difficult; thus only qualitative comparisons of the relative binding of the three guests could be made based on host titrations. In the case of G4 and G5 dendrimers, the order of binding strength was qualitatively determined to be 1,8-ANS<2,6-ANS indicating that the more streamlined 2,6-substituted probes are a better match for the dendrimer cavity shape than the bulkier 1,8-substituted probe. This order of binding strength was also indicated by double fluorometric titration experiments, involving both host and guest titrations. Further double fluorometric titration experiments on 2,6-ANS in G4 dendrimer revealed a host concentration-dependent change in the nature of the host: guest complexation, with multiple guests complexed per host molecule at very low host concentrations, but less than one guest per host at higher concentrations.

[The estimation of glomerular filtration rate using prediction equations]. / Procjena glomerularne filtracije s pomocu prediktivnih jednadzbi.

In clinical practice, serum creatinine is most commonly used to estimate glomerular filtration rate (GF) although it is well known that serum creatinine may be influenced by GF and factors independent of GF (age, sex, race, body size, diet, certain drugs and analytical methods). Creatinine clearance is a more sensitive marker of GF, but it overestimates GF because of tubular secretion of creatinine, and it often involves errors in 24-hour urine collection. According to the NKF/KDOQI (National Kidney Foundation Kidney Disease Outcome Quality Initiative) guidelines, the level of GF should be estimated from prediction equations taking into accout serum creatinine concentration and demographic characteristics. The aim of this work is to emphasize the clinical usefulness of these equations in estimating GF. Using prediction equations to estimate GF does not require timed urine collection susceptible to errors which are the most common underlying cause of unreliable estimation of GF done by creatinine clearance.

Slow oxidation of high density lipoproteins as studied by EPR spectroscopy.

There is relatively little information on the role of high density lipoprotein (HDL) oxidation in atherogenesis although there are indications that oxidation might affect atheroprotective activities of HDL. Recently we reported the study on LDL oxidation initiated and sustained by traces of the transition metal ions under conditions, which favor slow oxidation. Here we report the results of the analogous study on the oxidation of the two HDL subclasses. The oxidation process was monitored by measuring the time dependence of oxygen consumption and concentration of the spin-trapped free radicals using EPR spectroscopy. In both HDL2 and HDL3 subclasses, the dependence of the oxidation process on the copper/lipoprotein molar ratio is different from that in LDL dispersions. Comparison of the kinetic profiles of HDL2 and HDL3 oxidation revealed that under all studied experimental conditions HDL2 was more susceptible to copper-induced oxidation than HDL3.

Evaluation of the Konelab 20XT clinical chemistry analyzer.

The Konelab 20XT (Thermo Electron Oy, Finland) is a clinical chemistry analyzer for colorimetric, immunoturbidimetric and ion-selective electrode measurements. The aim of our work was to evaluate the analytical performances of the Konelab 20XT according to the European Clinical Chemistry Laboratory Standards Guidelines. A total of 30 analytes including substrates, enzymes, electrolytes and specific proteins were tested. Investigation results showed low imprecision (within-run coefficient of variation was below 3.5% and between-day coefficient of variation was less than 2.5% for most analytes at all three levels studied) and acceptable accuracy of the analyzer. No significant sample- or reagent-related carry-over was found. It was demonstrated that the analytical system operates within the claimed linearity ranges. The results compared well with those obtained by instruments routinely used in our laboratory (Olympus AU2700, Behring Nephelometer II). In general, the data on interference by hemoglobin, hyperbilirubinemia and turbidity are in accordance with known facts. However, slight hemolysis was found to interfere with the alkaline phosphatase (ALP) assay and mild lipemia affected the glucose assay. The Konelab 20XT is an easy-to-use analyzer that is suitable for routine and emergency analyses in small laboratories.

Probabilistic kinetic model of slow oxidation of low-density lipoprotein: I. Theory.

The microscopic probabilistic model has been introduced to explain the kinetics of very slow oxidation of low-density lipoprotein (LDL) from human plasma. The LDL oxidation, carried out in very unfavorable conditions, is assumed to be initiated by the traces of the transition-metal ions associated with the lipoprotein. The substrates for the metal-ion attack are alpha-tocopherol and the pre-formed lipid hydroperoxide. The theory assumes oscillation of the metal ions and alpha-tocopherol from the oxidized to the reduced states. In this model alpha-tocopherol acts as a pro-oxidant. The entire oxidation process consists of rare bursts of events in individual LDL particles. The reactions within the particles are treated in terms of probabilities of individual active species to participate in a specified reaction. The circular flow of the radical reactions could be visualized as circular flow of microscopic probabilities. The empirical, macroscopic quantities are quantitatively related with the microscopic probabilities, determined by a set of five adjustable parameters. The differential equations describing the initial radical generation rate and the rates of change of concentration of oxygen, hydroperoxide, co-antioxidant and trapped radicals in an LDL system are numerically solved in a finite difference approach.

Probabilistic kinetic model of slow oxidation of low-density lipoprotein: II. Experiments.

Theoretical probabilistic kinetic model has been applied to describe the measurements of several oxidation markers as a function of time, during slow oxidation of low-density lipoprotein (LDL). It has been demonstrated that such a process could be described as tocopherol-mediated peroxidation (TMP), initiated and sustained by the action of copper ions, present in LDL in trace amounts. In that process concentration of alpha-tocopherol remains essentially unaltered. Tocopherol and copper ions act as catalysts, oscillating between the oxidized and reduced states. The fitting of the theoretical model to the experimental data resulted in determination of the numerical values for the kinetic parameters. It has been found that the parameter values used for the fitting of the data collected for a number of samples from various donors differ rather little. The kinetic chain length of 1.3 (in presence of co-antioxidants) and 2.9 (in the absence of co-antioxidants) is shorter than found by others. The difference probably comes from the much lower concentration of copper ions in our systems (about 0.1 ion per LDL particle).