Удалители для асфальтосмолопарафиновых отложений месторождений Западного Казахстана

Signal transducers and activators of transcriptions (STAT) are key mediators of cytokine signaling. Moreover, these transcription factors play a crucial role in oncogenic signaling where inappropriate and sustained activation of STATs, especially STAT3, is a trait of many different cancers and their derived cell lines. Constitutively active STAT3 has been reported to prevent programmed cell death and enhance cell proliferation, whereas the disruption of STAT3 signaling can inhibit tumor growth. The physiologic activation of STAT3 by cytokines has been well established; however, little is known about altered, stimulation-independent STAT3 activation. Here, we show that, in most but not all melanoma cell lines, STAT3 phosphorylation increased substantially with cell density and that this STAT3 was able to bind to DNA and to activate transcription. Inhibitor studies showed that the cell density-dependent STAT3 activation relies on Janus kinases (JAK) rather than Src kinases. Using a specific JAK inhibitor, sustained STAT3 activation was completely abrogated in all tested melanoma lines, whereas inhibition of Src or mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1/2 had no effect on constitutively tyrosine-phosphorylated STAT3 levels. Although STAT3 activation was completely blocked with JAK inhibitor I and to a lesser extent with the common JAK inhibitor AG490, only the latter compound markedly decreased proliferation and induced apoptosis. Taken together, variations in cell density can profoundly modify the extent of JAK-mediated persistent STAT3 phosphorylation; however, STAT3 activation was not sufficient to provide critical growth and survival signals in melanoma cell lines

IL-24: a classic cytokine and/or a potential cure for cancer?

IL-24, a member of the IL-10 family of cytokines, is produced by monocytes and Th2 cells. Interestingly, immune cells do not appear to express specific IL-24 receptor chains (IL-20R1/IL-20R2 and IL-22R/IL-20R2), it is therefore unlikely that IL-24 has classical immune-modulating properties. Skin, on the other hand, seems to represent a major target tissue for IL-24 and related cytokines such as IL-19, -20, and -22. However, the initial interest in IL-24 did not arise from its physiological signalling properties through its cognate receptors but rather because of its tentative ability to selectively kill different cancer cells. In an attempt to further investigate the signalling events underlying the IL-24-induced cancer cell death, we found that melanoma cell lines did not react in the expected and previously described way. Using several different forms and delivery modes of IL-24, we were unable to detect any apoptosis-inducing properties of this cytokine in melanoma cells. In the present "Point of view" we will briefly summarise these findings and put them in context of published reports stating that IL-24 might be a long sought after treatment for several types of cancer

Distinct Cargos of Small Extracellular Vesicles Derived from Hypoxic Cells and Their Effect on Cancer Cells

Hypoxia is a common hallmark of solid tumors and is associated with aggressiveness, metastasis and poor outcome. Cancer cells under hypoxia undergo changes in metabolism and there is an intense crosstalk between cancer cells and cells from the tumor microenvironment. This cross talk is facilitated by small extracellular vesicles (sEVs; diameter between 30 and 200 nm), including exosomes and microvesicles, which carry a cargo of proteins, mRNA, ncRNA and other biological molecules. Hypoxia is known to increase secretion of sEVs and has an impact on the composition of the cargo. This sEV-mediated crosstalk ultimately leads to various biological effects in the proximal tumor microenvironment but also at distant, future metastatic sites. In this review, we discuss the changes induced by hypoxia on sEV secretion and their cargo as well as their effects on the behaviour and metabolism of cancer cells, the tumor microenvironment and metastatic events

Recombinant Interleukin-24 Lacks Apoptosis-Inducing Properties in Melanoma Cells

IL-24, also known as melanoma differentiation antigen 7 (mda-7), is a member of the IL-10 family of cytokines and is mainly produced by Th2 cells as well as by activated monocytes. Binding of IL-24 to either of its two possible heterodimeric receptors IL-20R1/IL-20R2 and IL-22R/IL-20R2 activates STAT3 and/or STAT1 in target tissues such as lung, testis, ovary, keratinocytes and skin. To date, the physiological properties of IL-24 are still not well understood but available data suggest that IL-24 affects epidermal functions by increasing proliferation of dermal cells. In stark contrast to its “normal” and physiological behaviour, IL-24 has been reported to selectively and efficiently kill a vast variety of cancer cells, especially melanoma cells, independent of receptor expression and Jak-STAT signalling. These intriguing properties have led to the development of adenovirally-expressed IL-24, which is currently being evaluated in clinical trials. Using three different methods, we have analysed a large panel of melanoma cell lines with respect to IL-24 and IL-24 receptor expression and found that none of the investigated cell lines expressed sufficient amounts of functional receptor pairs and therefore did not react to IL-24 stimulation with Jak/STAT activation. Results for three cell lines contrasted with previous studies, which reported presence of IL-24 receptors and activation of STAT3 following IL-24 stimulation. Furthermore, evaluating four different sources and modes of IL-24 administration (commercial recombinant IL-24, bacterially expressed GST-IL-24 fusion protein, IL-24 produced from transfected Hek cells, transiently over-expressed IL-24) no induction or increase in cell death was detected when compared to appropriate control treatments. Thus, we conclude that the cytokine IL-24 itself has no cancer-specific apoptosis-inducing properties in melanoma cells

Many ways to resistance: How melanoma cells evade targeted therapies

Melanoma is an aggressive malignancy originating from pigment-producing melanocytes. The development of targeted therapies (MAPK pathway inhibitors) and immunotherapies (immune checkpoint inhibitors) led to a substantial improvement in overall survival of patients. However, the long-term efficacy of such treatments is limited by side effects, lack of clinical effects and the rapidly emerging resistance to treatment. A number of molecular mechanisms underlying this resistant phenotype have already been elucidated. In this review, we summarise currently available treatment options for metastatic melanoma and the known resistance mechanisms to targeted therapies. A focus will be placed on “phenotype switching” as a mechanism and driver of drug resistance, together with an overview of novel approaches to circumvent resistance. A large body of recent data and literature suggests that tumour progression and phenotype switching could be better controlled and development of resistance prevented or at least delayed, by combining drugs targeting fast- and slow-proliferating cells

Effect of a four-week oral Phe administration on neural activation and cerebral blood flow in adults with early-treated phenylketonuria.

BACKGROUND Phenylketonuria (PKU) is a rare inborn error of metabolism characterized by impaired catabolism of the amino acid phenylalanine (Phe) into tyrosine. Cross-sectional studies suggest slight alterations in cognitive performance and neural activation in adults with early-treated PKU. The influence of high Phe levels on brain function in adulthood, however, remains insufficiently studied. Therefore, we aimed to explore the effect of a four-week period of oral Phe administration - simulating a controlled discontinuation of Phe restriction and raising Phe to an off-diet scenario - on working memory-related neural activation and cerebral blood flow (CBF). METHODS We conducted a randomized, placebo-controlled, double-blind, crossover, non-inferiority trial to assess the effect of a high Phe load on working memory-related neural activation and CBF in early-treated adults with classical PKU. Twenty-seven patients with early-treated classical PKU were included and underwent functional magnetic resonance imaging (fMRI) of the working memory network and arterial spin labeling (ASL) MRI to assess CBF before and after a four-week intervention with Phe and placebo. At each of the four study visits, fMRI working memory task performance (reaction time and accuracy) and plasma Phe, tyrosine, and tryptophan levels were obtained. Additionally, cerebral Phe was determined by 1H-MR spectroscopy. RESULTS Plasma Phe and cerebral Phe were significantly increased after the Phe intervention. However, no significant effect of Phe compared to placebo was found on neural activation and CBF. Regarding fMRI task performance, a significant impact of the Phe intervention on 1-back reaction time was observed with slower reaction times following the Phe intervention, whereas 3-back reaction time and accuracy did not differ following the Phe intervention compared to the placebo intervention. CONCLUSION Results from this present trial simulating a four-week discontinuation of the Phe-restricted diet showed that a high Phe load did not uniformly affect neural markers and cognition in a statistically significant manner. These results further contribute to the discussion on safe Phe levels during adulthood and suggest that a four-week discontinuation of Phe-restricted diet does not demonstrate significant changes in brain function

Compromised white matter is related to lower cognitive performance in adults with phenylketonuria.

Despite increasing knowledge about the effects of phenylketonuria on brain structure and function, it is uncertain whether white matter microstructure is affected and if it is linked to patients' metabolic control or cognitive performance. Thus, we quantitatively assessed white matter characteristics in adults with phenylketonuria and assessed their relationship to concurrent brain and blood phenylalanine levels, historical metabolic control and cognitive performance. Diffusion tensor imaging and 1H spectroscopy were performed in 30 adults with early-treated classical phenylketonuria (median age 35.5 years) and 54 healthy controls (median age 29.3 years). Fractional anisotropy and mean, axial and radial diffusivity were investigated using tract-based spatial statistics, and white matter lesion load was evaluated. Brain phenylalanine levels were measured with 1H spectroscopy whereas concurrent plasma phenylalanine levels were assessed after an overnight fast. Retrospective phenylalanine levels were collected to estimate historical metabolic control, and a neuropsychological evaluation assessed the performance in executive functions, attention and processing speed. Widespread reductions in mean diffusivity, axial diffusivity and fractional anisotropy occurred in patients compared to controls. Mean diffusivity and axial diffusivity were decreased in several white matter tracts and were most restricted in the optic radiation (effect size rrb = 0.66 to 0.78, P < 0.001) and posterior corona radiata (rrb = 0.83 to 0.90, P < 0.001). Lower fractional anisotropy was found in the optic radiation and posterior corona radiata (rrb = 0.43 to 0.49, P < 0.001). White matter microstructure in patients was significantly associated with cognition. Specifically, inhibition was related to axial diffusivity in the external capsule (rs = -0.69, P < 0.001) and the superior (rs = -0.58, P < 0.001) and inferior longitudinal fasciculi (rs = -0.60, P < 0.001). Cognitive flexibility was associated with mean diffusivity of the posterior limb of the internal capsule (rs = -0.62, P < 0.001), and divided attention correlated with fractional anisotropy of the external capsule (rs = -0.61, P < 0.001). Neither concurrent nor historical metabolic control was significantly associated with white matter microstructure. White matter lesions were present in 29 out of 30 patients (96.7%), most often in the parietal and occipital lobes. However, total white matter lesion load scores were unrelated to patients' cognitive performance and metabolic control. In conclusion, our findings demonstrate that white matter alterations in early-treated phenylketonuria persist into adulthood, are most prominent in the posterior white matter and are likely to be driven by axonal damage. Furthermore, diffusion tensor imaging metrics in adults with phenylketonuria were related to performance in attention and executive functions

Kinase inhibitor library screening identifies synergistic drug combinations effective in sensitive and resistant melanoma cells

Background: Melanoma is the most aggressive and deadly form of skin cancer with increasing case numbers worldwide. The development of inhibitors targeting mutated BRAF (found in around 60% of melanoma patients) has markedly improved overall survival of patients with late-stage tumors, even more so when combined with MEK inhibitors targeting the same signaling pathway. However, invariably patients become resistant to this targeted therapy resulting in rapid progression with treatment-refractory disease. The purpose of this study was the identification of new kinase inhibitors that do not lead to the development of resistance in combination with BRAF inhibitors (BRAFi), or that could be of clinical benefit as a 2nd line treatment for late-stage melanoma patients that have already developed resistance. Methods: We have screened a 274-compound kinase inhibitor library in 3 BRAF mutant melanoma cell lines (each one sensitive or made resistant to 2 distinct BRAFi). The screening results were validated by dose-response studies and confirmed the killing efficacies of many kinase inhibitors. Two different tools were applied to investigate and quantify potential synergistic effects of drug combinations: the Chou-Talalay method and the Synergyfinder application. In order to exclude that resistance to the new treatments might occur at later time points, synergistic combinations were administered to fluorescently labelled parental and resistant cells over a period of > 10 weeks. Results: Eight inhibitors targeting Wee1, Checkpoint kinase 1/2, Aurora kinase, MEK, Polo-like kinase, PI3K and Focal adhesion kinase killed melanoma cells synergistically when combined with a BRAFi. Additionally, combination of a Wee1 and Chk inhibitor showed synergistic killing effects not only on sensitive cell lines, but also on intrinsically BRAFi- and treatment induced-resistant melanoma cells. First in vivo studies confirmed these observations. Interestingly, continuous treatment with several of these drugs, alone or in combination, did not lead to emergence of resistance. Conclusions: Here, we have identified new, previously unexplored (in the framework of BRAFi resistance) inhibitors that have an effect not only on sensitive but also on BRAFi-resistant cells. These promising combinations together with the new immunotherapies could be an important step towards improved 1st and 2nd line treatments for late-stage melanoma patients

MiRNAs from serum-derived extracellular vesicles as biomarkers for uveal melanoma progression

Uveal melanoma (UM) is a rare type of malignancy that originates from melanocytes located in the choroid, iris and the ciliary body of the eye. UM has a very high mortality upon metastatic spread to the liver, the prime target organ for UM metastasis. The lack of effective therapies for advanced stages of the disease aggravate the prognosis further. Moreover, biomarkers for early detection and progression of UM, especially the molecular traits governing the development of metastasis, are still not available in clinical practice. One extensively studied components of liquid biopsies are exosomes, a subtype of extracellular vesicle. Due to their unique molecular cargo, they could be used as carriers of early markers of cancer development and progression. For characterisation of the miRNA profiles present in circulating serum-derived exosomes of patients with diagnosed primary and metastatic UM, we have analysed the miRNA cargos using next-generation sequencing followed by RT-qPCR validation in a cohort of patients (control n=20; primary n=9; metastatic n=11). Nine miRNAs clearly differentiating these patient groups have been established. We show that hsa-miR-223 and hsa-miR-203a are the most promising biomarker candidates, allowing categorization of patients into local and advanced UM. Additionally, the comparison of miRNA expression levels in exosomes derived from UM patients with those derived from healthy donors, revealed that hsa-miR-144 has the potential to be used as an early marker for presence of UM. Taken together, this pilot study reveals that miRNAs extracted from circulating exosomes could be exploited as potential biomarkers in UM diagnosis and, more importantly, for indicating metastatic spread

Systematic transcriptional profiling of responses to STAT1- and STAT3- activating cytokines in different cancer types

Cytokines orchestrate responses to pathogens and in inflammatory processes but they also play an important role in cancer by shaping the expression levels of cytokine response genes. Here, we conducted a large profiling study comparing miRNome and mRNA transcriptome data generated following different cytokine stimulations. Transcriptomic responses to STAT1- (IFN, IL-27) and STAT3-activating cytokines (IL6, OSM) were systematically compared in nine cancerous and nonneoplastic cell lines of different tissue origins (skin, liver and colon). The largest variation in our datasets was seen between cell lines of the three different tissues rather than stimuli. Notably, the variability in miRNome datasets was a lot more pronounced than in mRNA data. Our data also revealed that cells of skin, liver and colon tissues respond very differently to cytokines and that the cell signaling networks activated or silenced in response to STAT1- or STAT3- activating cytokines are specific to the tissue and the type of cytokine. However, globally, STAT1-activating cytokines had stronger effects than STAT3-inducing cytokines with most significant responses in liver cells, showing more genes up-regulated and with higher fold change. A more detailed analysis of gene regulations upon cytokine stimulation in these cells provided insights into STAT1- versus STAT3-driven processes in hepatocarcinogenesis. Finally, independent component analysis revealed interconnected transcriptional networks distinct between cancer cells and their healthy counterparts