Оценка выбросов в атмосферу отходящих дымовых газов ТЭЦ и технологий их переработки

Сравнительная оценка выбросов в атмосферу отходящих дымовых газов, при сжигании органических топлив и способы их переработки.Comparative assessment of emissions of flue gases into the atmosphere, during combustion of organic fuels and methods of their processing

Modulation of SOCS protein expression influences the interferon responsiveness of human melanoma cells

<p>Abstract</p> <p>Background</p> <p>Endogenously produced interferons can regulate the growth of melanoma cells and are administered exogenously as therapeutic agents to patients with advanced cancer. We investigated the role of negative regulators of interferon signaling known as suppressors of cytokine signaling (SOCS) in mediating interferon-resistance in human melanoma cells.</p> <p>Methods</p> <p>Basal and interferon-alpha (IFN-α) or interferon-gamma (IFN-γ)-induced expression of SOCS1 and SOCS3 proteins was evaluated by immunoblot analysis in a panel of n = 10 metastatic human melanoma cell lines, in human embryonic melanocytes (HEM), and radial or vertical growth phase melanoma cells. Over-expression of SOCS1 and SOCS3 proteins in melanoma cells was achieved using the PINCO retroviral vector, while siRNA were used to inhibit SOCS1 and SOCS3 expression. Tyr⁷⁰¹-phosphorylated STAT1 (P-STAT1) was measured by intracellular flow cytometry and IFN-stimulated gene expression was measured by Real Time PCR.</p> <p>Results</p> <p>SOCS1 and SOCS3 proteins were expressed at basal levels in melanocytes and in all melanoma cell lines examined. Expression of the SOCS1 and SOCS3 proteins was also enhanced following stimulation of a subset of cell lines with IFN-α or IFN-γ. Over-expression of SOCS proteins in melanoma cell lines led to significant inhibition of Tyr⁷⁰¹-phosphorylated STAT1 (P-STAT1) and gene expression following stimulation with IFN-α (IFIT2, OAS-1, ISG-15) or IFN-γ (IRF1). Conversely, siRNA inhibition of SOCS1 and SOCS3 expression in melanoma cells enhanced their responsiveness to interferon stimulation.</p> <p>Conclusions</p> <p>These data demonstrate that SOCS proteins are expressed in human melanoma cell lines and their modulation can influence the responsiveness of melanoma cells to IFN-α and IFN-γ.</p

Cytokine resistance in melanoma

Cytokines play an important role in the growth regulation of melanoma cells. Whereas the growth of melanocytes and many early stage melanoma cells can be inhibited by cytokines, melanoma cells of advanced tumor stages have often been reported to be “multi-cytokine resistant”. Thus, the aim of this study was to investigate the molecular mechanisms underlying cytokine resistance of melanoma cells. Transcription factors of the STAT family are crucial in signal transduction of cytokines. Previously, it has been reported that methylation of STAT1 on a conserved arginine residue (Arg31) is important for STAT1 function and loss of this modification was proposed to be involved in interferon resistance of cancer cells. Since STAT3 is involved in growth inhibition of melanoma cells, in the first part of this thesis I thus investigated the arginine methylation of STAT3 and STAT1. Here I provide several independent lines of evidence that did not support the occurrence of arginine methylation of STAT1 or STAT3. First, it was shown that the anti-methylarginine antibodies did not precipitate specifically STAT1 or STAT3. Second, it was shown that the methylation inhibitors, MTA and MDA, had profound and rapid effects on phosphorylation of STAT1 and STAT3, but MDA additionally also affected the p38 and Erk signaling cascades which are known to cross-talk with the Jak/STAT pathway. Third, it was shown that mutation of Arg31 to Lys led to destabilization of STAT1 and STAT3, implicating an important structural role of Arg31. Finally, the in vitro methylation assay using purified catalytically active protein arginine methyltransferases (PRMT1, -2, -3, -4, and -6) demonstrated that STAT proteins are not methylated, and cotransfection of PRMT1 did not affect STAT1-controlled reporter gene activity. Taken together, the data presented in this thesis suggest the absence of arginine methylation of STAT1 and STAT3. The Jak/STAT signaling pathway is subject to feedback inhibition by members of the suppressors of cytokine signaling (SOCS) family. In the second part of this thesis, I analysed the melanoma cell line 1286, resistant towards the growth-inhibitory effects of IL-6 and OSM, to better understand the mechanisms underlying cytokine resistance. Although the relevant receptors gp130 and OSMR are expressed at the cell surface of these cells, cytokine stimulation hardly led to activation of Jak1, STAT3 and STAT1. I found a high level constitutive expression of SOCS3 that did not further increase after cytokine treatment. Importantly, upon suppression of SOCS3 by short interfering RNA, cells became susceptible towards OSM and IL-6: they showed an enhanced STAT3 phosphorylation and a dramatically increased STAT1 phosphorylation. Moreover, suppression of SOCS3 rendered 1286 cells sensitive to the anti-proliferative action of IL-6 and OSM, but not of IFN-alpha. Interestingly, SOCS3-siRNA treatment also increased the growth-inhibitory effect in cytokine-sensitive WM239 cells expressing SOCS3 in an inducible way. Thus, SOCS3 expression confers a growth advantage to these cell lines. Constitutive SOCS3 mRNA expression, although at lower levels than in 1286 cells, was found in nine additional human melanoma cell lines and in normal human melanocytes while at protein level SOCS3 expression was marginal at best. However, in situ analysis of human melanoma specimens revealed SOCS3 immunoreactivity in 3 out of 10 samples suggesting that in vivo SOCS3 may possibly play a role in IL-6 resistance in at least a fraction of tumors

Asiatic Acid Inhibits Nasopharyngeal Carcinoma Cell Viability and Migration via Suppressing STAT3 and Claudin-1

Nasopharyngeal carcinoma (NPC) is a prevalent cancer in Southeast Asia, but effective treatment options remain limited, and chemotherapy has a high resistance rate. Asiatic acid (AA), a triterpenoid found in Centella asiatica, has shown anticancer activity in various cancers. Therefore, this study aims to investigate the anticancer effects and mechanisms of AA in NPC cell lines. The effects of AA on NPC cytotoxicity, apoptosis, and migration were determined in TW-01 and SUNE5-8F NPC cell lines. Western blot analysis was performed to evaluate the protein expression levels affected by AA. The role of AA in proliferation and migration was investigated in STAT3 and claudin-1 knockdown cells. AA inhibited NPC cell viability and migration and induced cell death by increasing cleaved caspase-3 expression. Moreover, AA inhibited STAT3 phosphorylation and reduced claudin-1 expression in NPC cells. Although knockdown of STAT3 or claudin-1 slightly reduced cell viability, it did not enhance the anti-proliferative effect of AA. However, knockdown of STAT3 or claudin-1 increased the anti-migratory effect of AA in NPC cells. These results suggest that AA can be a promising candidate for drug development against NPC

Comparative Proteomic Analysis of Human Cholangiocarcinoma Cell Lines: S100A2 as a Potential Candidate Protein Inducer of Invasion

Cholangiocarcinoma (CCA) is a bile duct cancer, commonly found in Asia including Thailand and especially in the northeastern region of Thailand. To identify the proteins involved in carcinogenesis and metastasis of CCA, protein expression profiles of high-invasive KKU-M213 and low-invasive KKU-100 cell lines were compared using a comparative GeLC-MS/MS proteomics analysis. A total of 651 differentially expressed proteins were detected of which 27 protein candidates were identified as having functions involved in cell motility. A total of 22 proteins were significantly upregulated in KKU-M213, whereas 5 proteins were downregulated in KKU-M213. S100A2, a calcium-binding protein in S100 protein family, is upregulated in KKU-M213. S100A2 is implicated in metastasis development in several cancers. The protein expression level of S100A2 was verified by Western blot analysis. Intriguingly, high-invasive KKU-M213 cells showed higher expression of S100A2 than KKU-100 cells, consistent with proteomic data, suggesting that S100A2 may be a key protein involved in the progression of CCA. However, the biological function of S100A2 in cholangiocarcinoma remains to be elucidated. S100A2 might be a potential biomarker as well as a novel therapeutic target in CCA metastasis

Constitutive suppressor of cytokine signaling 3 expression confers a growth advantage to a human melanoma cell line

The growth of melanocytes and many early stage melanoma cells can be inhibited by cytokines, whereas late stage melanoma cells have often been reported to be "multi-cytokine-resistant." Here, we analyzed the melanoma cell line 1286, resistant towards the growth-inhibitory effects of interleukin 6 (IL-6), and oncostatin M (OSM), to better understand the mechanisms underlying cytokine resistance. Although the relevant receptors gp130 and OSMR are expressed at the cell surface of these cells, cytokine stimulation hardly led to the activation of Janus kinase 1 and signal transducer and activator of transcription (STAT)3 and STAT1. We found a high-level constitutive expression of suppressors of cytokine signaling 3 (SOCS3) that did not further increase after cytokine treatment. Importantly, upon suppression of SOCS3 by short interfering RNA, cells became susceptible towards OSM and IL-6: they showed an enhanced STAT3 phosphorylation and a dramatically increased STAT1 phosphorylation. Moreover, suppression of SOCS3 rendered 1286 cells sensitive to the antiproliferative action of IL-6 and OSM, but not of IFN-alpha. Interestingly, SOCS3-short interfering RNA treatment also increased the growth-inhibitory effect in cytokine-sensitive WM239 cells expressing SOCS3 in an inducible way. Thus, SOCS3 expression confers a growth advantage to these cell lines. Constitutive SOCS3 mRNA expression, although at lower levels than in 1286 cells, was found in nine additional human melanoma cell lines and in normal human melanocytes, although at the protein level, SOCS3 expression was marginal at best. However, in situ analysis of human melanoma specimens revealed SOCS3 immunoreactivity in 3 out of 10 samples, suggesting that in vivo SOCS3 may possibly play a role in IL-6 resistance in at least a fraction of tumors

Are STATS arginine-methylated?

Transcription factors of the STAT (signal transducer and activator of transcription) family are important in signal transduction of cytokines. They are subject to post-translational modification by phosphorylation on tyrosine and serine residues. Recent evidence suggested that STATs are methylated on a conserved arginine residue within the N-terminal region. STAT arginine methylation has been described to be important for STAT function and loss of arginine methylation was discussed to be involved in interferon resistance of cancer cells. Here we provide several independent lines of evidence indicating that the issue of arginine methylation of STATs has to be reassessed. First, we show that treatment of melanoma and fibrosarcoma cells with inhibitors used to suppress methylation (N-methyl-2-deoxyadenosine, adenosine, dl-homocysteine) had profound and rapid effects on phosphorylation of STAT1 and STAT3 but also on p38 and Erk signaling cascades which are known to cross-talk with the Jak/STAT pathway. Second, we show that anti-methylarginine antibodies did not precipitate specifically STAT1 or STAT3. Third, we show that mutation of Arg(31) to Lys led to destabilization of STAT1 and STAT3, implicating an important structural role of Arg(31). Finally, purified catalytically active protein arginine methyltransferases (PRMT1, -2, -3, -4, and -6) did not methylate STAT proteins, and cotransfection with PRMT1 did not affect STAT1-controlled reporter gene activity. Taken together, our data suggest the absence of arginine methylation of STAT1 and STAT3

Characterization of methylthioadenosin phosphorylase (MTAP) expression in malignant melanoma

Homozygous deletions of human chromosomal region 9p21 occur frequently in malignant melanoma and are associated with the loss of the tumor suppressor genes p16(INK4a) and p15(INK4b). In the same chromosomal region the methylthioadenosine phosphorylase (MTAP) gene is localized and therefore may also serve as a tumor suppressor gene. The aim of this study was to analyze MTAP mutations and expression patterns in malignant melanomas. To examine the MTAP gene and expression of MTAP protein we screened 9 human melanoma cell lines and primary human melanocytes by reverse transcriptase-polymerase chain reaction, sequencing, and immunoblotting. Analyzing the melanoma cell lines we found significant down-regulation of MTAP mRNA expression. In only one cell line, HTZ19d, this was due to homozygous deletion of exon 2 to 8 whereas in the other cell lines promoter hypermethylation was detected. MTAP expression was further analyzed in vivo by immunohistochemical staining of 38 tissue samples of benign melanocytic nevi, melanomas, and melanoma metastases. In summary, we demonstrate significant inverse correlation between MTAP protein expression and progression of melanocytic tumors as the amount of MTAP protein staining decreases from benign melanocytic nevi to metastatic melanomas. Our results suggest an important role of MTAP inactivation in the development of melanomas. This finding may be of great clinical significance because recently an association between MTAP activity and interferon sensitivity has been suggested