Nuclear factor kappa B subunit p50 promotes melanoma angiogenesis by upregulating interleukin-6 expression

The Atypical MAP Kinase MAPK15 Is Required for Lung Adenocarcinoma Metastasis via Its Interaction with NF-κB p50 Subunit and Transcriptional Regulation of Prostaglandin E2 Receptor EP3 Subtype

Studying the relatively underexplored atypical MAP Kinase MAPK15 on cancer progression/patient outcomes and its potential transcriptional regulation of downstream genes would be highly valuable for the diagnosis, prognosis, and potential oncotherapy of malignant tumors such as lung adenocarcinoma (LUAD). Here, the expression of MAPK15 in LUAD was detected by immunohistochemistry and its correlation with clinical parameters such as lymph node metastasis and clinical stage was analyzed. The correlation between the prostaglandin E2 receptor EP3 subtype (EP3) and MAPK15 expression in LUAD tissues was examined, and the transcriptional regulation of EP3 and cell migration by MAPK15 in LUAD cell lines were studied using the luciferase reporter assay, immunoblot analysis, qRT-PCR, and transwell assay. We found that MAPK15 is highly expressed in LUAD with lymph node metastasis. In addition, EP3 is positively correlated with the expression of MAPK15 in LUAD tissues, and we confirmed that MAPK15 transcriptionally regulates the expression of EP3. Upon the knockdown of MAPK15, the expression of EP3 was down-regulated and the cell migration ability was decreased in vitro; similarly, the mesenteric metastasis ability of the MAPK15 knockdown cells was inhibited in in vivo animal experiments. Mechanistically, we demonstrate for the first time that MAPK15 interacts with NF-κB p50 and enters the nucleus, and NF-κB p50 binds to the EP3 promoter and transcriptionally regulates the expression of EP3. Taken together, we show that a novel atypical MAPK and NF-κB subunit interaction promotes LUAD cell migration through transcriptional regulation of EP3, and higher MAPK15 level is associated with lymph node metastasis in patients with LUAD.

Analysis of differentially expressed genes responsible for the suppressive effect of anisomycin on cell proliferation of DLD-1 cells

Anisomycin is used as a chemical compound that possesses c-Jun N-terminal kinase (JNK)-activating effects. Recently, the potent anti-tumor effects of anisomycin have received much attention. In addition to its JNK-activating effects, anisomycin has been reported to affect gene expression in osteosarcoma, leukemia, hepatocellular carcinoma, ovarian cancer and other cancers. We previously demonstrated that anisomycin induced the degradation of transcription factor GATA-6 in DLD-1 cells (a colorectal cancer cell line) and inhibited their proliferation. However, the details of the gene network involved in the process remain unclear. In this study, we conducted an RNA-seq analysis of differentially expressed genes (DEGs) in anisomycin-treated DLD-1 cells to identify the molecular process of growth-suppressive genes. We found that LAMB3, which regulates cell adhesion and migration, and NFKB2 were down-regulated by anisomycin. In addition, the mRNA expression of several tumor suppressor genes (ATF3, ERRFI1, KLF6, and AKAP12) was transiently enhanced at 3 h after anisomycin treatment. These results suggest that anisomycin blocks a PI3K/Akt-signaling cascade to lead to the suppression of cell growth.

Cutaneous melanoma dissemination is dependent on the malignant cell properties and factors of intercellular crosstalk in the cancer microenvironment (Review)

The incidence of cutaneous malignant melanoma has been steadily increasing worldwide for several decades. This phenomenon seems to follow the trend observed in many types of malignancies caused by multiple significant factors, including ageing. Despite the progress in cutaneous malignant melanoma therapeutic options, the curability of advanced disease after metastasis represents a serious challenge for further research. In this review, we summarise data on the microenvironment of cutaneous malignant melanoma with emphasis on intercellular signalling during the disease progression. Malignant melanocytes with features of neural crest stem cells interact with non‑malignant populations within this microenvironment. We focus on representative bioactive factors regulating this intercellular crosstalk. We describe the possible key factors and signalling cascades responsible for the high complexity of the melanoma microenvironment and its premetastatic niches. Furthermore, we present the concept of melanoma early becoming a systemic disease. This systemic effect is presented as a background for the new horizons in the therapy of cutaneous melanoma.

Probing the Global Cellular Responses to Lipotoxicity Caused by Saturated Fatty Acids

Excessive levels of saturated fatty acids are toxic to cells, although the basis for this lipotoxicity remains incompletely understood. Here, we analyzed the transcriptome, lipidome, and genetic interactions of human leukemia cells exposed to palmitate. Palmitate treatment increased saturated glycerolipids, accompanied by a transcriptional stress response, including upregulation of the endoplasmic reticulum (ER) stress response. A comprehensive genome-wide short hairpin RNA (shRNA) screen identified >350 genes modulating lipotoxicity. Among previously unknown genetic modifiers of lipotoxicity, depletion of RNF213, a putative ubiquitin ligase mutated in Moyamoya vascular disease, protected cells from lipotoxicity. On a broader level, integration of our comprehensive datasets revealed that changes in di-saturated glycerolipids, but not other lipid classes, are central to lipotoxicity in this model. Consistent with this, inhibition of ER-localized glycerol-3-phosphate acyltransferase activity protected from all aspects of lipotoxicity. Identification of genes modulating the response to saturated fatty acids may reveal novel therapeutic strategies for treating metabolic diseases linked to lipotoxicity.

Anticancer effects of alloxanthoxyletin and fatty acids esters - In vitro study on cancer HTB-140 and A549 cells

Alloxanthoxyletin, a natural occurring pyranocoumarin isolated from a number of plant sources, such as family of Rutaceae, and its synthetic derivatives show cytotoxic and antitumor activities. In the present study new eleven esters of alloxanthoxyletin and fatty acids were synthesized and evaluated for their anticancer toxicity. The structures of the compounds were confirmed by Proton Nuclear Magnetic Resonance (¹H NMR), Carbon-13 Nuclear Magnetic Resonance (¹³C NMR) and High Resolution Mass Spectrometry (HRMS) analyses. For all compounds 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine the cytotoxic effect on human melanoma cells (HTB-140), human epithelial lung carcinoma cells (A549) and human keratinocyte line (HaCaT). For the most active compounds (8-11) lactate dehydrogenase (LDH) assay to assess the level of cell damage as well as migration inhibition assay were performed. To explain the basic mechanism of cell death induction, the effect of derivatives 8-11 on early and late apoptosis in Annexin V-FITC/7-AAD flow cytometry analysis was investigated. The results indicate that human melanoma cells (HTB-140) and human epithelial lung carcinoma cells (A549) were more sensitive to new alloxanthoxyletin derivatives exposure compared to human keratinocytes (HaCaT). Both, the cytotoxicity and the migration tests showed a concentration-dependent inhibition of cell growth, although with a different degree of efficacy. Tested compounds induced apoptosis in cancer cells, however, derivatives 8, 9, 10 and 11 were found to be much more potent inducers of early apoptosis in HTB-140 cells than in A549 and HaCaT cells. To establish the potent mechanism of action of alloxanthoxyletin derivatives 8, 9, 10 and 11 on HaCaT, A549 and HTB-140 cells, the level of IL-6 was measured. Our results indicate, that tested compounds significantly decrease the release of IL-6 for all cancer cell lines.

Differential expression of NF-κB heterodimer RelA/p50 in human urothelial carcinoma

Background

Urothelial carcinoma (UC) is the fifth most common malignancy that accounts for 5% of all cancers. Diagnostic markers that predict UC progressions are inadequate. NF-κB contributes towards disease progression upon constitutive activation in many solid tumors. The nuclear localization of NF-κB indicates increased transcriptional activity while cytoplasmic localization indicates the inactive protein repository that can be utilized readily by a malignant cell. This study delineates the nuclear and cytoplasmic differential expression of NF-κB heterodimers in UC progression.

Methods

The involvement of the NF-κB proteins in UC was analyzed in silico using cytoscape. The expression of NF-κB heterodimers was analyzed by immunohistochemistry.

Results

PINA4MS app in cytoscape revealed over expression of RelA and suppression of NF-κB1 (p50 precursor) in UC whereas the expression of NF-κB target proteins remained unhindered. Immunohistochemical localization showed nuclear RelA/p50 in low grade UC whereas in high grade only RelA expression was observed. Conversely, cytoplasmic expression of RelA/p50 remained extensive across high and low grade UC tissues (p < 0.005). RelA nuclear and cytoplasmic expression (p < 0.005) was directly proportional to the disease progression. In our study, some of the high-grade UC tissues with squamous differentiation and muscle invasion had extensive nuclear p50 localization. The phenomenon of RelA/p50 expression seen increased in low-grade UC than high grade UC might be due to their interaction with other members of NF-κB family of proteins. Thus, NF-κB RelA/p50 differential expression may play a unique role in UC pathogenesis and can serve as a biomarker for diagnosis.

Downregulated TRPV1 Expression Contributes to Melanoma Growth via the Calcineurin-ATF3-p53 Pathway

Melanoma is the most lethal form of skin cancer with increasing incidence over the years. Because of its rapid proliferative and drastic metastatic capacity, the prognosis of melanoma remains dismal, although the targeted therapy and immunotherapy have gained revolutionary progress recently. Therefore, it is of necessity to further clarify the mechanism of melanoma pathogenesis for developing an alternative treatment strategy. Transient receptor potential vanilloid 1 (TRPV1) is a nonselective Ca²⁺ channel greatly involved in regulating cell apoptosis, proliferation, metabolism, and cancer development, but its role in melanoma remains unknown. Herein, we first found that TRPV1 expression was significantly decreased in melanoma tissues and cell lines, compared with nevus tissues and normal melanocytes, respectively. We then proved that TRPV1 overexpression or its agonist capsaicin treatment inhibited melanoma growth by activating p53 and inducing cell apoptosis. A subsequent mechanistic study revealed that TRPV1 induced Ca²⁺ influx to regulate p53 activation via calcineurin-ATF3 transcriptional cascade. Finally, the effect of TRPV1 on melanoma growth was proved in vivo. Altogether, our study demonstrates that TRPV1 is a potential tumor suppressor in melanoma.

Pre-S2 Start Codon Mutation of Hepatitis B Virus Subgenotype B3 Effects on NF-κB Expression and Activation in Huh7 Cell Lines

A cross-sectional study on hepatitis B patients in Indonesia showed association of pre-S2 start codon mutation (M120 V) with cirrhosis and hepatocellular carcinoma (HCC), which was dissimilar from studies from other populations where pre-S2 deletion mutation was more prevalent. Different mutation patterns were attributed to different hepatitis B virus (HBV) subgenotypes in each population study. HBV surface proteins are reported to induce the activation of NF-κB, a transcriptional factor known to play an important role in the development of liver disease. This study aimed to see the effects of HBs variants in HBV subgenotype B3 on the expression and activation of NF-κB as one of the mechanisms in inducing advanced liver disease. HBV subgenotypes B3, each carrying wild-type (wt) HBs, M120 V, and pre-S2 deletion mutation were isolated from three HCC patients. HBs genes were amplified and cloned into pcDNA3.1 and were transfected using Lipofectamine into a Huh7 cell line. NF-κB activation was measured through IκB-α expression, which is regulated by NF-κB. RNA expressions for HBs, IκB-α, and NF-κB subunit (p50) were evaluated using real-time PCR. M120 V mutant had a significantly higher mRNA level compared with wt and pre-S2 deletion mutant; however, there were no significant differences in HBs protein expressions. The transcription level of p50 was higher in M120 V mutation compared with HBs wild-type and pre-S2 deletion mutant. NF-κB activation was higher in HBs wild-type compared with the two mutant variants. Pre-S2 mutations had no effect on the increment of NF-κB activation. However, M120 V mutation may utilize a different pathway in liver disease progression that involves high expression of NF-κB subunit, p50.

microRNA-7-5p inhibits melanoma cell proliferation and metastasis by suppressing RelA/NF-κB

microRNA-7-5p (miR-7-5p) is a tumor suppressor in multiple cancer types and inhibits growth and invasion by suppressing expression and activity of the epidermal growth factor receptor (EGFR) signaling pathway. While melanoma is not typically EGFR-driven, expression of miR-7-5p is reduced in metastatic tumors compared to primary melanoma. Here, we investigated the biological and clinical significance of miR-7-5p in melanoma. We found that augmenting miR-7-5p expression in vitro markedly reduced tumor cell viability, colony formation and induced cell cycle arrest. Furthermore, ectopic expression of miR-7-5p reduced migration and invasion of melanoma cells in vitro and reduced metastasis in vivo. We used cDNA microarray analysis to identify a subset of putative miR-7-5p target genes associated with melanoma and metastasis. Of these, we confirmed nuclear factor kappa B (NF-κB) subunit RelA, as a novel direct target of miR-7-5p in melanoma cells, such that miR-7-5p suppresses NF-κB activity to decrease expression of canonical NF-κB target genes, including IL-1β, IL-6 and IL-8. Importantly, the effects of miR-7-5p on melanoma cell growth, cell cycle, migration and invasion were recapitulated by RelA knockdown. Finally, analysis of gene array datasets from multiple melanoma patient cohorts revealed an association between elevated RelA expression and poor survival, further emphasizing the clinical significance of RelA and its downstream signaling effectors. Taken together, our data show that miR-7-5p is a potent inhibitor of melanoma growth and metastasis, in part through its inactivation of RelA/NF-κB signaling. Furthermore, miR-7-5p replacement therapy could have a role in the treatment of this disease.

RNA-Seq revealed ATF3-regulated inflammation induced by silica

BACKGROUND

Millions of workers are exposed to dust containing silica. Chronic and over-exposure to silica will lead to silicosis, which is an irreversible and sometimes fatal lung disease. The disordered physiological processes of silicosis consist of accumulation of silica particles in the alveoli of the lung. Then, the ingestion of the silica particles by macrophages was followed by an inflammatory response. Up till now, the chest radiographs remain the key tool in diagnosing and assessing the extent of silicosis. However, concerns exist regarding the sensitivity and specificity of the technique. Therefore, there is still a need to develop a biomarker for silicosis for early detection of silicosis.

METHOD

In this study, RNA-Seq was applied to detect the gene expression changes when silica was exposed to macrophages at different time intervals. RNA-Seq provides a broader dynamic range, increased specificity and sensitivity, and easier detection of rare and low-abundance transcripts. Bioinformatics tools such as the Database for Annotation, Visualization and Integrated Discovery (DAVID) and Gene Functional Classification Tool and Search Tool for the Retrieval of Interacting Genes (STRING) were applied for data analysis. Quantitative PCR was used to validate the results.

RESULTS

Our results showed that regulation of transcription factors was the dominant activated pathway in early exposure of silica to macrophages, followed by inflammatory responses which were the main mechanisms in silicosis. One of the findings was the upregulation of activating transcription factor 3 (ATF3) during silica exposure. When ATF3 expression was inhibited by siRNA, the production of cytokines IL-1β, IL-6 and TNF was further increased.

CONCLUSION

This indicated that ATF3 may be a potential early diagnostic biomarker for silicosis and ATF3 acts as a repressor in inflammatory responses induced by silica.

Mutant DD genotype of NFKB1 gene is associated with the susceptibility and severity of coronary artery disease

Nuclear factor κappa B (NF-κB) is an important transcription factor in the development and progression of coronary artery disease (CAD). Recent evidence suggests that -94 ATTG ins/del mutant in the promoter of NFKB1 gene is an essential functional mutant. The present study demonstrated the frequencies of the del/del (DD) genotype and del (D) allele were significantly higher in CAD patients than in controls. CAD patients carrying mutant DD genotype had worse stenosis of diseased coronary arteries compared to those carrying ins/ins (II) or ins/del (ID) genotype. Plasma levels of endothelial nitric oxide synthase (eNOS) were lower, while inflammatory cytokine incnterlukin-6 (IL-6) was higher in CAD patients with DD genotype than those with II or ID genotype (both P<0.05). In vitro study showed that mutant human umbilical vein endothelial cells (DD genotype HUVECs) were more susceptible to H₂O₂-induced apoptosis, which was accompanied with a decreased Bcl-2 expression. Further, mutant HUVECs had lower eNOS but higher IL-6 mRNA levels and decreased phosphorylation of eNOS under H₂O₂-stimulation (both P<0.05). Compared to wild type cells (II genotype), significantly downregulated protein expression of total NF-κB p50 subunit were observed in mutant HUVECs with or without oxidative stress, and a lower expression of unclear p50 was associated with a decreased p50 nuclear translocation in mutant HUVECs versus wild type cells under H₂O₂-stimulation (both P<0.05). In conclusion, mutant DD genotype of NFKB1 gene is associated with the risk and severity of CAD. Dwonregulation of NF-κB p50 subunit leads to exacerbated endothelial dysfunction and apoptosis and enhanced inflammatory response that is the potential underlying mechanism.

Adapt, Recycle, and Move on: Proteostasis and Trafficking Mechanisms in Melanoma

Melanoma has emerged as a paradigm of a highly aggressive and plastic cancer, capable to co-opt the tumor stroma in order to adapt to the hostile microenvironment, suppress immunosurveillance mechanisms, and disseminate. In particular, oncogene- and aneuploidy-driven dysregulations of proteostasis in melanoma cells impose a rewiring of central proteostatic processes, such as the heat shock and unfolded protein responses, autophagy, and the endo-lysosomal system, to avoid proteotoxicity. Research over the past decade has indicated that alterations in key nodes of these proteostasis pathways act in conjunction with crucial oncogenic drivers to increase intrinsic adaptations of melanoma cells against proteotoxic stress, modulate the high metabolic demand of these cancer cells and the interface with other stromal cells, through the heightened release of soluble factors or exosomes. Here, we overview and discuss how key proteostasis pathways and vesicular trafficking mechanisms are turned into vital conduits of melanoma progression, by supporting cancer cell's adaptation to the microenvironment, limiting or modulating the ability to respond to therapy and fueling melanoma dissemination.

Downregulation of ACE2/Ang-(1-7)/Mas axis promotes breast cancer metastasis by enhancing store-operated calcium entry

The renin-angiotensin system (RAS) is an important component of the tumor microenvironment and plays a key role in promoting cancer cell proliferation, angiogenesis, metabolism, migration and invasion. Meanwhile, the arm of angiotensin-converting enzyme (ACE)2/angiotensin-(1-7) [Ang-(1-7)]/Mas axis in connection with RAS is associated with anti-proliferative, vasodilatory and anti-metastatic properties. Previous studies have shown that Ang-(1-7) reduces the proliferation of orthotopic human breast tumor growth by inhibiting cancer-associated fibroblasts. However, the role of ACE/Ang-(1-7)/Mas axis in the metastasis of breast cancer cells is still unknown. In the present study, we found that ACE2 protein level is negatively correlated with the metastatic ability of breast cancer cells and breast tumor grade. Upregulation of ACE2/Ang-(1-7)/Mas axis inhibits breast cancer cell migration and invasion in vivo and in vitro. Mechanistically, ACE2/Ang-(1-7)/Mas axis activation inhibits store-operated calcium entry (SOCE) and PAK1/NF-κB/Snail1 pathways, and induces E-cadherin expression. In summary, our results demonstrate that downregulation of ACE2/Ang-(1-7)/Mas axis stimulates breast cancer metastasis through the activation of SOCE and PAK1/NF-κB/Snail1 pathways. These results provide new mechanisms by which breast cancer develop metastasis and shed light on developing novel anti-metastasis therapeutics for metastatic breast cancer by modulating ACE2/Ang-(1-7)/Mas axis.

p53 modulates NF-κB mediated epithelial-to-mesenchymal transition in head and neck squamous cell carcinoma

OBJECTIVES

To investigate the role of p53 in NF-κB mediated epithelial-to-mesenchymal (EMT) in head and neck squamous cell carcinoma (HNSCC).

MATERIALS AND METHODS

We utilized HNSCC and normal oral epithelial cell lines as our model system. We used a lentiviral shRNA system to silence the expression of p65 and p53 in these cell lines. Mutant and wild-type (WT) p53 background genotypes were analyzed. The expression of epithelial and mesenchymal markers was determined using western blotting and quantitative PCR assays. Cell morphology, growth, and invasion were determined using a 3-dimensional spheroid culture and anchorage independent growth (AIG) assays.

RESULTS

In HNSCC cells with mutant p53 we found that silencing p65 expression promoted EMT. In contrast, in the context of WT p53, ectopic p65 over-expression promoted EMT. Ablation of WT p53 in normal oral epithelial cells blocked EMT induced by p65 over-expression. We demonstrate that AIG and apoptosis induced by NF-κB activation is regulated by p53.

CONCLUSION

Our data demonstrates that p53 mutational status is critical in determining the outcome of NF-κB activation in HNSCC. In the presence of WT p53, excess p65 signal can promote EMT. Conversely, ablation of p65 in the context of mutant p53 drives EMT. These results demonstrate that p53 mutational status alters the outcome of NF-κB signaling. These results, though preliminary, demonstrate the critical role of p53 mutational status in determining the outcome of NF-κB signaling and suggest that monitoring p53 status may inform the utility of NF-κB inhibitor treatment in HNSCC.

The role of the metastasis suppressor gene KAI1 in melanoma angiogenesis

The tetraspan protein KAI1 (CD82) has been previously shown to have important roles in cell migration, invasion, and melanoma prognosis. In this study, we investigated the role of KAI1 regarding melanoma angiogenesis. KAI1 overexpression strongly suppressed the growth of the human umbilical vein endothelial cells and their tubular structure formation in vitro. Also, KAI1 was able to inhibit both interleukin-6 (IL-6) and VEGF at mRNA and protein levels. Using nude mice in the in vivo study, we showed that KAI1, through the regulation of ING4, inhibited blood vessel formation in matrigel plugs along with the downregulation of IL-6 and VEGF, and the recruitment of CD31-positive cells. Finally, we found that KAI1 was able to suppress the activity of a serine/threonine kinase Akt by suppressing Akt phosphorylation (Ser473). Taken together, our results suggested that KAI1 was able to suppress melanoma angiogenesis by downregulating IL-6 and VEGF expression, and the restoration of KAI1 functionality offered a new approach in human melanoma treatment.

Comprehensive Evaluation of Nuclear Factor-κΒ Expression Patterns in Non-Small Cell Lung Cancer

Nuclear factor (NF)-κB signalling is required for lung adenocarcinoma development in mice, and both of its subunits RelA and RelB were independently reported to be highly expressed in human non-small cell lung cancer (NSCLC). To comprehensively examine NF-κB expression in NSCLC, we analyzed serial sections of primary tumor samples from 77 well-documented patients (36 adenocarcinomas, 40 squamous cell carcinomas and 3 large cell carcinomas) for immunoreactivity of RelA, RelB, P50, and P52/P100. Tumor and intratumoral stroma areas were discriminated based on proliferating cell nuclear antigen immunoreactivity and inflammatory infiltration was assessed in intratumoral stroma areas. NF-κB immunoreactivity was quantified by intensity, extent, and nuclear localization and was cross-examined with tumor cell proliferation, inflammatory infiltration, and clinical-pathologic data. We found that the expression of the different NF-κB subunits was not concordant, warranting our integral approach. Overall, RelA, RelB, and P50 were expressed at higher levels compared with P52/P100. However, RelA and P50 were predominantly expressed in intratumoral stroma, but RelB in tumor cells. Importantly, tumor area RelA expression was correlated with the intensity of inflammatory infiltration, whereas RelB expression was identified in proliferating tumor cells. Using multiple logistic regression, we identified that tumor RelB expression was an independent predictor of lymph node metastasis, and tumor P50 was an independent predictor of TNM6 stage IIB or higher, whereas tumor RelA was an independent predictor of inflammatory infiltration. We conclude that pathologic studies of NF-κB expression in cancer should include multiple pathway components. Utilizing such an approach, we identified intriguing associations between distinct NF-κB subunits and clinical and pathologic features of NSCLC.

Hypoxia-independent drivers of melanoma angiogenesis

Tumor angiogenesis is a process which is traditionally regarded as the tumor’s response to low nutrient supply occurring under hypoxic conditions. However, hypoxia is not a pre-requisite for angiogenesis. The fact that even single tumor cells or small tumor cell aggregates are capable of attracting blood vessels reveals the early metastatic capability of tumor cells. This review sheds light on the hypoxia-independent mechanisms of tumor angiogenesis in melanoma.

The multifaceted role of CD146/MCAM in the promotion of melanoma progression

Human malignant melanoma is a common primary malignant cutaneous tumour derived from transformed epidermal melanocytes. Patients with melanoma have a high rate of mortality due to resistance to chemotherapeutic drugs, a major obstacle to a successful treatment. Several reports have suggested that CD146 plays an important role as a signalling molecule in human melanoma. This role includes CD146 as a participant in inflammation, differentiation, adhesion, tumourigenicity, metastasis, invasion and angiogenesis among other processes, which suggests that this molecule promotes the progression of human melanoma as a multifaceted regulator. In this article, we explore the effects and corresponding mechanisms with respect to the role of CD146/MUC18 in the promotion of human melanoma progression. Collectively, the studies indicated that targeting CD146, because it is a suitable marker of poor patient outcome, might be useful in the design of future strategies for the prevention and treatment of human melanoma.

The role of microRNAs and long non-coding RNAs in the pathology, diagnosis, and management of melanoma

Melanoma is frequently lethal and its global incidence is steadily increasing. Despite the rapid development of different modes of targeted treatment, durable clinical responses remain elusive. A complete understanding of the molecular mechanisms that drive melanomagenesis is required, both genetic and epigenetic, in order to improve prevention, diagnosis, and treatment. There is increased appreciation of the role of microRNAs (miRNAs) in melanoma biology, including in proliferation, cell cycle, migration, invasion, and immune evasion. Data are also emerging on the role of long non-coding RNAs (lncRNAs), such as SPRY4-IT1, BANCR, and HOTAIR, in melanomagenesis. Here we review the data on the miRNAs and lncRNAs implicated in melanoma biology. An overview of these studies will be useful for providing insights into mechanisms of melanoma development and the miRNAs and lncRNAs that might be useful biomarkers or future therapeutic targets.

miR-98 suppresses melanoma metastasis through a negative feedback loop with its target gene IL-6

Dysregulated microRNA (miRNA) expression has a critical role in tumor development and metastasis. However, the mechanism by which miRNAs control melanoma metastasis is unknown. Here, we report reduced miR-98 expression in melanoma tissues with increasing tumor stage as well as metastasis; its expression is also negatively associated with melanoma patient survival. Furthermore, we demonstrate that miR-98 inhibits melanoma cell migration in vitro as well as metastatic tumor size in vivo. We also found that IL-6 is a target gene of miR-98, and IL-6 represses miR-98 levels via the Stat3-NF-κB-lin28B pathway. In an in vivo melanoma model, we demonstrate that miR-98 reduces melanoma metastasis and increases survival in part by reducing IL-6 levels; it also decreases Stat3 and p65 phosphorylation as well as lin28B mRNA levels. These results suggest that miR-98 inhibits melanoma metastasis in part through a novel miR-98-IL-6-negative feedback loop.

Mechanisms of tumour vascularization in cutaneous malignant melanoma: clinical implications

Malignant melanoma represents < 10% of all skin cancers but is responsible for the majority of skin-cancer-related deaths. Metastatic melanoma has historically been considered as one of the most therapeutically challenging malignancies. Fortunately, for the first time after decades of basic research and clinical investigation, new drugs have produced major clinical responses. Angiogenesis has been considered an important target for cancer treatment. Initial efforts have focused primarily on targeting endothelial and tumour-related vascular endothelial growth factor signalling. Here, we review different mechanisms of tumour vascularization described in melanoma and discuss the potential clinical implications.

ING4 regulates JWA in angiogenesis and their prognostic value in melanoma patients

Background:

We previously showed that inhibitor of growth family member 4 (ING4) inhibits melanoma angiogenesis, and JWA suppresses the metastasis of melanoma cells. As angiogenesis is essential for tumour metastasis, further investigation of the function of ING4 and JWA in melanoma angiogenesis is needed, and their prognostic value are of great interest.

Methods:

Western blot, tube-formation assays and luciferase assays were used to investigate the correlation between ING4 and JWA in melanoma angiogenesis. JWA and integrin-linked kinase (ILK) expression was determined on a tissue microarray constructed from 175 biopsies.

Results:

ING4 promoted JWA expression by activating JWA promoter. Furthermore, the regulation of growth and tube formation of endothelial cells by ING4 was partially JWA dependent. Also, ING4 inhibited the ILK-induced angiogenesis signalling pathway via JWA. Moreover, reduced JWA, or increased ILK, expression was closely associated with 5-year disease-specific survival of melanoma patients (P=0.001 and 0.007, respectively). There was also a positive correlation between ING4 and JWA yet a negative correlation between ING4 and ILK. Importantly, their concomitant expressions were significantly related to 5-year survival of melanoma patients (P=0.002 and 0.003, respectively).

Conclusion:

JWA has an important role in ING4-regulated melanoma angiogenesis, and ING4/JWA/ILK are promising prognostic markers and may be used as anti-angiogenic therapeutic targets for melanoma.

NFκB1 (p50) suppresses SOD2 expression by inhibiting FoxO3a transactivation in a miR190/PHLPP1/Akt-dependent axis

This study reports a novel function of p50 in its regulation of SOD2 transcription via an NFκB-independent pathway. p50-regulated FoxO3a phosphorylation and transactivation contributes to SOD2 transcription, and p50–down-regulated PHLPP1 translation via miR190 is responsible for activation of Akt and FoxO3a.

The biological functions of nuclear factor κB1 (NFκB1; p50) have not been studied as often as those of other members of the NFκB family due to its lack of a transcriptional domain. Our recent studies showed that p50 functions as an apoptotic mediator via its inhibition of GADD45α protein degradation and increase in p53 protein translation. Here we report a novel function of p50 in its regulation of superoxide dismutase 2 (SOD2) transcription via an NFκB-independent pathway. We find that deletion of p50 in mouse embryonic fibroblasts (MEFs; p50^−/−) up-regulates SOD2 expression at both protein and mRNA levels. SOD2 promoter–driven luciferase is also up-regulated in p50^−/− cells compared with wild-type (WT) MEF (p50^+/+) cells, suggesting p50 regulation of SOD2 at the transcriptional level. Our results also show that p50 deficiency specifically results in down-regulation of phosphorylation and increased transactivation of FoxO3a compared with WT cells. Further studies indicate that p50–down-regulated FoxO3a phosphorylation is mediated by activated Akt via up-regulation of microRNA 190 (miR190), in turn inhibiting PH domain and leucine-rich repeat protein phosphatase 1 (PHLPP1) translation. Together our studies identify a novel p50 function in the regulation of SOD2 transcription by modulating the miR190/PHLPP1/Akt-FoxO3a pathway, which provides significant insight into the physiological function of p50.

JWA inhibits melanoma angiogenesis by suppressing ILK signaling and is an independent prognostic biomarker for melanoma

Melanoma is the deadliest cutaneous malignancy because of its high incidence of metastasis. Melanoma growth and metastasis relies on sustained angiogenesis; therefore, inhibiting angiogenesis is a promising approach to treat metastatic melanoma. JWA is a novel microtubule-associated protein and our previous work revealed that JWA inhibited melanoma cell invasion and metastasis. However, the role of JWA in melanoma angiogenesis and the prognostic value are still unknown. Here, we report that JWA in melanoma cells significantly inhibited the tube formation of endothelial cells. In addition, JWA regulated integrin-linked kinase (ILK) through integrin αVβ3 and such regulation was achieved through the transcription factor Sp1. Notably, both in vitro and in vivo angiogenesis assays revealed that JWA dramatically suppressed melanoma angiogenesis by inhibiting ILK signaling. Furthermore, we examined the expression of JWA protein in a large set of melanocytic lesions (n = 505) at different stages by tissue microarray and found an inverse correlation between JWA expression and melanoma progression (P = 5 × 10(-6)). Importantly, reduced JWA expression was correlated with a poorer overall, and disease-specific 5 year survival of patients (P = 0.001 and 0.007, respectively). Multivariate Cox regression analyses indicated that JWA was an independent prognostic marker for melanoma patients. Moreover, we found a significant negative correlation between JWA and ILK in melanoma biopsies, and their concomitant expression was closely correlated with melanoma patient survival (P = 0.004), further indicating the regulation of ILK expression by JWA is critical in melanoma. Taken together, our data highlight the function of JWA in melanoma angiogenesis and reveal the clinical prognostic value of JWA.

Interleukin-6: an angiogenic target in solid tumours

During the past decade, incorporating anti-angiogenic agents into the therapeutic management of a myriad of malignancies has in certain cases made a significant impact on survival. However, the development of resistance to these drugs is inevitable and swift disease progression on their cessation often ensues. Hence, there is a drive to devise strategies that aim to enhance response to anti-angiogenic therapies by combining them with other targeted agents that facilitate evasion from resistance. The pleiotropic cytokine, interleukin-6 (IL-6), exerts pro-angiogenic effects in the tumour microenvironment of several solid malignancies and there is emerging evidence that reveals significant relationships between IL-6 signalling and treatment failure with antibodies directed against vascular endothelial growth factor (VEGF). This review summarises the role of IL-6 in pivotal angiogenic processes and preclinical/clinical research to support the future introduction of anti-IL-6 therapies to be utilised either in combination with other anti-angiogenic drugs or as a salvage therapy for patients with diseases that become refractory to these approaches.

BAG-1 interacts with the p50-p50 homodimeric NF-κB complex: implications for colorectal carcinogenesis

Understanding the mechanisms that promote aberrant tumour cell survival is critical for the determination of novel strategies to combat colorectal cancer (CRC). We have recently shown that the anti-apoptotic protein BAG-1, highly expressed in pre-malignant and CRC tissue, can potentiate cell survival through regulating NF-κB transcriptional activity. In this study, we identify a novel complex between BAG-1 and the p50-p50 NF-κB homodimers, implicating BAG-1 as a co-regulator of an atypical NF-κB pathway. Importantly, the BAG-1-p50 complex was detected at gene regulatory sequences including the epidermal growth factor receptor (EGFR) and COX-2 (PTGS2) genes. Suppression of BAG-1 expression using small interfering RNA was shown to increase EGFR and suppress COX-2 expression in CRC cells. Furthermore, mouse embryonic fibroblasts derived from the NF-κB1 (p105/p50) knock-out mouse were used to demonstrate that p50 expression was required for BAG-1 to suppress EGFR expression. This was shown to be functionally relevant as attenuation of BAG-1 expression increased ligand activated phosphorylation of EGFR in CRC cells. In summary, this paper identifies a novel role for BAG-1 in modulating gene expression through interaction with the p50-p50 NF-κB complexes. Data presented led us to propose that BAG-1 can act as a selective regulator of p50-p50 NF-κB responsive genes in colorectal tumour cells, potentially important for the promotion of cell survival in the context of the fluctuating tumour microenvironment. As BAG-1 expression is increased in the developing adenoma through to metastatic lesions, understanding the function of the BAG-1-p50 NF-κB complexes may aid in identifying strategies for both the prevention and treatment of CRC.

Ellagic acid inhibits melanoma growth in vitro

Ellagic is a polyphenolic compound with anti-fibrotic and antioxidant properties, and exhibits antitumor properties against various cancer cells in vitro. There are few studies, however, which examine the effects of ellagic acid on melanoma. In the present study, we observe effects of ellagic acid on melanoma cells in vitro. Three metastatic melanoma cell lines (1205Lu, WM852c and A375) were examined to determine the effects of ellagic acid on melanoma cell viability, cell-cycle, apoptosis, NF-κβ activity, and IL-1β & IL-8 secretion. Cell viability assays demonstrated that ellagic acid possesses an inhibitory effect on cell proliferation at concentrations between 25 and 100 µM. In addition, ellagic acid promoted G1 cell cycle arrest, increased levels of apoptosis and decreased synthesis of IL-1β and IL-8 in melanoma cells. Ellagic acid also decreased NF-κβ activity, suggesting at least one potential mechanism by which ellagic acid may exert its effects in melanoma cells. Our findings support further investigation into prospective roles for ellagic acid as a therapeutic, adjuvant, or preventive agent for melanoma.

Critical roles of cold shock domain protein A as an endogenous angiogenesis inhibitor in skeletal muscle

Angiogenesis is regulated by the local balance between angiogenic stimulators and inhibitors and is maintained by muscle-derived angiogenic factors in ischemic tissues.

AIMS

Our objectives were to investigate the effect of cold shock domain protein A (CSDA) as an endogenous angiogenesis inhibitor and to develop a novel strategy of therapeutic angiogenesis by blocking CSDA expression.

RESULTS

In human skeletal muscle cells, CSDA was upregulated during hypoxia when cells were damaged and apoptosis was induced. CSDA expression could repress the activity of hypoxia inducible factor-1α and nuclear factor κB, because CSDA can competitively bind the hypoxia response element and the nuclear factor κB-binding element. As a result, vascular endothelial growth factor-A, interleukin-6, and interleukin-8 secretions from skeletal muscle cells were decreased. Further, CSDA depletion increased the secretion level of these angiogenic factors. In a hindlimb ischemia model, transfer of short-hairpin RNA targeting CSDA ameliorated ischemia without direct transfer of angiogenic factors. In this ischemic tissue, vascular endothelial growth factor-A, interleukin-6, and CXCL2 protein levels were increased.

INNOVATION AND CONCLUSION

CSDA appears to play a critical role as an endogenous angiogenesis inhibitor in skeletal muscle, and RNA interference targeting of CSDA is a promising gene therapy strategy for treating peripheral arterial disease.

Inhibitor of growth-4 mediates chromatin modification and has a suppressive effect on tumorigenesis and innate immunity

Inhibitor of growth-4 (ING4) is a member of the ING family and acts as a tumor suppressor protein. ING4 is a promising candidate for cancer research due to its anti-angiogenic function and its role in the inhibition of cell migration, cell cycle, and induction of apoptosis. Interaction of this protein with the histone acetyl transferase complex plays a vital role in the regulation of multiple nuclear factor kappa light chain enhancer of activated B cells response elements and thus in the regulation of innate immunity. Splice variants of ING4 have different binding affinities to target sites, which results in the enhancement of its functional diversity. ING4 is among the few known regulatory proteins that can directly interact with chromatin as well as with transcription factors. The influence of ING4 on tumor necrosis factor-α, keratinocyte chemoattractant, interleukin (IL)-6, IL-8, matrix metalloproteinases, cyclooxygenase-2, and IκBα expression clearly demonstrates its critical role in the regulation of inflammatory mediators. Its interaction with liprin α1 and p53 contribute to mitigate cell spreading and induce apoptosis of cancer cells. Multiple factors including breast cancer melanoma suppressor-1 are upstream regulators of ING4 and are frequently deactivated in tumor cells. In the present review, the different properties of ING4 are discussed, and its activities are correlated with different aspects of cell physiology. Special emphasis is placed on our current understanding of ING4 with respect to its influence on chromatin modification, tumorigenesis, and innate immunity.

MicroRNA-9 up-regulates E-cadherin through inhibition of NF-κB1-Snail1 pathway in melanoma

MicroRNAs (miRNAs) are short non-coding RNAs that post-transcriptionally regulate gene expression. Hsa-miR-9 has been shown to have opposite functions in different tumour types; however, the underlying mechanism is unclear. Here we show that hsa-miR-9 is down-regulated in metastatic melanomas compared to primary melanomas. Overexpression of miR-9 in melanoma cells resulted in significantly decreased cell proliferation and migratory capacity with decreased F-actin polymerization and down-regulation of multiple GTPases involved in cytoskeleton remodelling. miR-9 overexpression induced significant down-regulation of Snail1 with a concomitant increase in E-cadherin expression. In contrast, knockdown of miR-9 increased Snail1 expression as well as melanoma cell proliferation and migration capacity. Mechanistically, miR-9 expression down-regulated NF-κB1 in melanoma and the effect was abolished by mutations in the putative miR-9 binding sites within the 3'-untranslated region (UTR) of NF-κB1. Anti-miR-9 miRNA inhibitor also increased the expression of NF-κB1. The effects of miR-9 on Snail1 expression and melanoma cell proliferation and migration were rescued by overexpression of NF-κB1 in these cells. Furthermore, miR-9 overexpression resulted in significantly decreased melanoma growth and metastasis in vivo. In summary, miR-9 inhibits melanoma proliferation and metastasis through down-regulation of the NF-κB1-Snail1 pathway. This study finds a new mechanism that miR-9 utilizes to decrease E-cadherin expression and inhibit melanoma progression. The results suggest that function of microRNAs is context and tumour type-specific.

In vitro synergistic cytotoxic effect of triptolide combined with hydroxycamptothecin on pancreatic cancer cells

Pancreatic cancer is a devastating disease characterized by low sensitivity to conventional chemotherapeutic treatment that has a poor prognosis. Therefore, novel effective chemotherapeutic regimens need to be developed. In this study, we analyzed the combined cytotoxic effect of triptolide and hydroxycamptothecin (HCPT) on pancreatic cancer cell line PANC-1 by using 3-(4.5-dimethylthiazol-2-yl)-5-(3-carboxy-methoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) and fluorescence- activated cell sorting (FACS) assays. Our results showed that the sensitivity of a combined therapy using triptolide and HCPT was higher than that of triptolide or HCPT alone and that activation of caspase-9/caspase-3 and inhibition of nuclear factor-kappaB (NF-κB) signaling pathway may contribute to the synergistic cytotoxic effect of this combination therapy. Therefore, our observations provided evidence supporting the clinical applications of the combination chemotherapy using triptolide and HCPT for treating pancreatic cancer.

Expression of Id-1 is regulated by MCAM/MUC18: a missing link in melanoma progression

The acquisition of the metastatic melanoma phenotype is associated with increased expression of the melanoma cell adhesion molecule MCAM/MUC18 (CD146). However, the mechanism by which MUC18 contributes to melanoma metastasis remains unclear. Herein, we stably silenced MUC18 expression in two metastatic melanoma cell lines, A375SM and C8161, and conducted cDNA microarray analysis. We identified and validated that the transcriptional regulator, inhibitor of DNA binding-1 (Id-1), previously shown to function as an oncogene in several malignancies, including melanoma, was downregulated by 5.6-fold following MUC18 silencing. Additionally, we found that MUC18 regulated Id-1 expression at the transcriptional level via ATF-3, which itself was upregulated by 6.9-fold in our cDNA microarray analysis. ChIP analysis showed increased binding of ATF-3 to the Id-1 promoter after MUC18 silencing. To complement these studies, we rescued the expression of MUC18, which reversed the expression patterns of Id-1 and ATF-3. Moreover, we showed that MUC18 promotes melanoma invasion through Id-1, as overexpression of Id-1 in MUC18-silenced cells resulted in increased MMP-2 expression and activity. To our knowledge, this is the first demonstration that MUC18 is involved in cell signaling regulating the expression of Id-1 and ATF-3, thus contributing to melanoma metastasis.

Integrin-linked kinase regulates melanoma angiogenesis by activating NF-κB/interleukin-6 signaling pathway

Integrin-linked kinase (ILK) is a highly conserved serine-threonine protein kinase involved in cell-extracellular matrix interactions, cytoskeletal organization and cell signaling. Overexpression of ILK in epithelial cells leads to anchorage-independent growth with increased cell cycle progression. Previously, we have shown that ILK upregulation strongly correlates with melanoma progression, invasion and inversely correlates with 5-year survival of melanoma patients. However, the molecular mechanism by which ILK enhances melanoma progression is currently unknown. In the present study, we found that proangiogenic molecule interleukin-6 (IL-6) is the downstream target of ILK in melanoma cells. ILK overexpression increased IL-6, whereas silencing of ILK suppressed IL-6 expression at both messenger RNA and protein levels. ILK also altered the activity and subcellular localization of nuclear factor-kappaB (NF-κB) subunit p65. We further found that ILK enhanced the IL-6 gene transcription by promoting the binding of NF-κB p65 to IL-6 promoter. Moreover, ILK overexpression in melanoma cells enhanced the tube-forming ability of endothelial cells in vitro and microvessel formation in vivo. ILK-induced tube and blood vessel formation of endothelial cells was significantly reduced upon IL-6 inhibition in ILK-overexpressing melanoma cells. To delineate the mechanism by which ILK-induced IL-6 production can enhance angiogenesis, further analysis of the downstream targets of IL-6 signaling showed an increased activity of the signal transducer and activator of transcription 3 (STAT3) in ILK-overexpressing cells. As STAT3 binds to vascular endothelial growth factor (VEGF) promoter, we found that VEGF levels were elevated in ILK-overexpressing cells and declined upon transfection of IL-6 small interfering RNA, suggesting that ILK may regulate VEGF expression through IL-6 pathway by activating STAT3.

Cell cycle regulator ING4 is a suppressor of melanoma angiogenesis that is regulated by the metastasis suppressor BRMS1

ING4 has been previously shown to play important roles in regulating apoptosis, cell cycle progress, cell migration, and invasion. In this study, we investigated the impact of ING4 on melanoma angiogenesis. ING4 overexpression strongly suppressed the growth of human umbilical vein endothelial cells (HUVEC) and their ability to form tubular structure in vitro. We also found that ING4 inhibits interleukin-6 (IL-6) at both mRNA and protein levels through suppressing NF-κB activity. Knockdown of endogenous ING4 resulted in enhanced HUVEC growth and IL-6 expression. Our in vivo studies using nude mice confirmed that ING4 inhibited blood vessel formation and the recruitment of CD31-positive cells in matrigel plugs. Furthermore, we found that expression of ING4 was induced by BRMS1, a metastasis suppressor that inhibits melanoma angiogenesis through inhibiting NF-κB activity and IL-6 level as well. Further experiments showed that ING4 knockdown abrogated the suppressive effect of BRMS1 on HUVEC growth, whereas ING4 overexpression inhibited BRMS1 knockdown-induced angiogenesis, indicating that ING4 is a downstream target of BRMS1 in regulating tumor angiogenesis. Collectively, our findings indicate that ING4 is induced by BRMS1 and that it inhibits melanoma angiogenesis by suppressing NF-κB activity and IL-6 expression. Restoration of ING4 function offers a potential new strategy for the treatment of human melanoma.

Prognostic significance of BRMS1 expression in human melanoma and its role in tumor angiogenesis

Breast cancer metastasis suppressor 1 (BRMS1) has been reported to suppress metastasis without significantly affecting tumorigenicity in breast cancer and ovarian cancer. To investigate the role of BRMS1 in human melanoma progression and prognosis, we established tissue microarray and BRMS1 expression was evaluated by immunohistochemistry in 41 dysplastic nevi, 90 primary melanomas and 47 melanoma metastases. We found that BRMS1 expression was significantly decreased in metastatic melanoma compared with primary melanoma or dysplastic nevi (P=0.021 and 0.001, respectively, χ(2) test). In addition, reduced BRMS1 staining was significantly correlated with American Joint Committee on Cancer stages (P=0.011, χ(2) test), but not associated with tumor thickness, tumor ulceration and other clinicopathological parameters. Furthermore, BRMS1 expression was significantly correlated with disease-specific 5-year survival of melanoma patients (P=0.007, log-rank test). Multivariate Cox regression analysis revealed that BRMS1 staining was an independent prognostic factor for melanoma patients (relative risk=0.51; confidence interval=0.29-0.91; P=0.022). Moreover, we demonstrated that BRMS1 overexpression inhibited endothelial cell growth and tube formation ability by suppressing NF-κB activity and IL-6 expression in vitro. We also showed that knockdown of BRMS1 increased IL-6 expression and promoted endothelial cell growth and tube formation. In addition, our data revealed that the BRMS1-mediated IL-6 expression is dependent on NF-κB. Strikingly, our in vivo studies using nude mice confirmed that BRMS1 inhibited blood vessel formation and the recruitment of CD31-positive cells in matrigel plugs. Taken together, BRMS1 expression was decreased in metastatic melanomas, which resulted in deficient suppression of angiogenesis and contributed to melanoma progression. BRMS1 may serve an important prognostic marker and therapeutic target for melanoma patients.

Targeting NF-κB in infantile hemangioma-derived stem cells reduces VEGF-A expression

BACKGROUND

infantile hemangioma (IH) is a most common tumor of infancy. Using infantile hemangioma-derived stem cells (HemSCs), we recently demonstrated that corticosteroids suppress the expression of VEGF-A, monocyte chemoattractant protein-1 (MCP-1), urokinase plasminogen activator receptor (uPAR), and interleukin-6 (IL-6); each of these are known targets of the transcription factor nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB). In the present study, we examined the expression of these NF-κB target genes in IH tissue specimens and the effect of NF-κB regulation on the expression of pro-angiogenic cytokines, and in particular VEGF-A, in HemSCs.

MATERIALS AND METHODS

RNA extracted from IH tissue and hemangioma-derived stem cells (HemSCs) was used to analyze NF-κB target gene expression by reverse transcription-quantitative PCR (RT-qPCR). The effects of NF-κB blockade were examined in HemSCs. Immunostaining, immunoblotting and ELISA were used to assess protein expression.

RESULTS

MCP-1, uPAR, and IL-6 were found to be differentially expressed in proliferating versus involuting IH. Corticosteroids suppressed NF-κB activity of HemSCs. Velcade (Bortezomib), a proteosome inhibitor that can indirectly inhibit NF-κB, impaired HemSCs viability and expression of pro-angiogenic factors. Furthermore, specific inhibition of NF-κB resulted in suppression of VEGF-A.

CONCLUSIONS

we demonstrate expression of NF-κB target genes in proliferating IH. In addition, we show that the expression of several pro-angiogenic factors in HemSCs, and in particular VEGF-A, is regulated by NF-B activity.

Differential influence of normal and cancer-associated fibroblasts on the growth of human epithelial cells in an in vitro cocultivation model of prostate cancer

The prostate is composed of a number of different cell populations. The interaction between them is crucial for the development and proper function of the prostate. However, the effect of the molecular cross talk between these cells in the course of carcinogenesis is still unclear. Employing an approach wherein immortalized epithelial cells and immortalized human fibroblasts were cocultured, we show that normal associated fibroblasts (NAF) and cancer-associated fibroblasts (CAF) differentially influenced the growth and proliferation of immortalized human prostate epithelial cells. Whereas NAFs inhibited the growth of immortalized epithelial cells but promoted the growth of metastatic PC-3 cells, CAFs promoted the growth of immortalized epithelial cells but not of PC-3. Cytokine arrays revealed that NAFs secreted higher levels of tumor necrosis factor-alpha compared with CAFs whereas CAFs secreted higher levels of interleukin-6 (IL-6) compared with NAFs. The growth-inhibiting effects of NAFs were counteracted by the addition of IL-6, and the growth-promoting effects exerted by the CAFs were counteracted by tumor necrosis factor-alpha. Furthermore, CAFs induced the migration of endothelial cells in an IL-6-dependent manner. Here, we show that normal fibroblast cells have a protective function at very early stages of carcinogenesis by preventing immortalized epithelial cells from proliferating and forming new blood vessels whereas CAFs aid immortalized epithelial cells to further develop.

Alterations in gene expression in human mesothelial cells correlate with mineral pathogenicity

Human mesothelial cells (LP9/TERT-1) were exposed to low and high (15 and 75 microm(2)/cm(2) dish) equal surface area concentrations of crocidolite asbestos, nonfibrous talc, fine titanium dioxide (TiO2), or glass beads for 8 or 24 hours. RNA was then isolated for Affymetrix microarrays, GeneSifter analysis and QRT-PCR. Gene changes by asbestos were concentration- and time-dependent. At low nontoxic concentrations, asbestos caused significant changes in mRNA expression of 29 genes at 8 hours and of 205 genes at 24 hours, whereas changes in mRNA levels of 236 genes occurred in cells exposed to high concentrations of asbestos for 8 hours. Human primary pleural mesothelial cells also showed the same patterns of increased gene expression by asbestos. Nonfibrous talc at low concentrations in LP9/TERT-1 mesothelial cells caused increased expression of 1 gene Activating Transcription Factor 3 (ATF3) at 8 hours and no changes at 24 hours, whereas expression levels of 30 genes were elevated at 8 hours at high talc concentrations. Fine TiO2 or glass beads caused no changes in gene expression. In human ovarian epithelial (IOSE) cells, asbestos at high concentrations elevated expression of two genes (NR4A2, MIP2) at 8 hours and 16 genes at 24 hours that were distinct from those elevated in mesothelial cells. Since ATF3 was the most highly expressed gene by asbestos, its functional importance in cytokine production by LP9/TERT-1 cells was assessed using siRNA approaches. Results reveal that ATF3 modulates production of inflammatory cytokines (IL-1 beta, IL-13, G-CSF) and growth factors (VEGF and PDGF-BB) in human mesothelial cells.