Tumor necrosis factor-α induces epithelial-mesenchymal transition of renal cell carcinoma cells via a nuclear factor kappa B-independent mechanism

Metabolic reprogramming of the retinal pigment epithelium by cytokines associated with age-related macular degeneration

The complex metabolic relationship between the retinal pigment epithelium (RPE) and photoreceptors is essential for maintaining retinal health. Recent evidence indicates the RPE acts as an adjacent lactate sink, suppressing glycolysis in the epithelium in order to maximize glycolysis in the photoreceptors. Dysregulated metabolism within the RPE has been implicated in the pathogenesis of age-related macular degeneration (AMD), a leading cause of vision loss. In the present study, we investigate the effects of four cytokines associated with AMD, TNFα, TGF-β2, IL-6, and IL-1β, as well as a cocktail containing all four cytokines, on RPE metabolism using ARPE-19 cells, primary human RPE cells, and ex vivo rat eyecups. Strikingly, we found cytokine-specific changes in numerous metabolic markers including lactate production, glucose consumption, extracellular acidification rate, and oxygen consumption rate accompanied by increases in total mitochondrial volume and ATP production. Together, all four cytokines could potently override the constitutive suppression of glycolysis in the RPE, through a mechanism independent of PI3K/AKT, MEK/ERK, or NF-κB. Finally, we observed changes in glycolytic gene expression with cytokine treatment, including in lactate dehydrogenase subunit and glucose transporter expression. Our findings provide new insights into the metabolic changes in the RPE under inflammatory conditions and highlight potential therapeutic targets for AMD.

Mannan-binding lectin ameliorates renal fibrosis by suppressing macrophage-to-myofibroblast transition

Mannan-binding lectin (MBL) is a pattern-recognition molecule that plays a crucial role in innate immunity. MBL deficiency correlates with an increased risk of chronic kidney disease (CKD). However, the molecular mechanisms are not fully defined. Here, we established a CKD model in wild-type (WT) and MBL-deficient (MBL-/-) mice via unilateral ureteral obstruction (UUO). The result showed that MBL deficiency aggravated the pathogenesis of renal fibrosis in CKD mice. Strikingly, the in vivo macrophage depletion investigation revealed that macrophages play an essential role in the MBL-mediated suppression of renal fibrosis. We found that MBL limited the progression of macrophage-to-myofibroblast transition (MMT) in kidney tissues of UUO mice. Further in vitro study showed that MBL-/- macrophages exhibited significantly increased levels of fibrotic-related molecules compared with WT cells upon transforming growth factor beta (TGF-β) stimulation. We demonstrated that MBL inhibited the MMT process by suppressing the production of matrix metalloproteinase 9 (MMP-9) and activation of Akt signaling. In summary, our study revealed an expected role of MBL on macrophage transition during renal fibrosis, thus offering new insight into the potential of MBL as a therapeutic target for CKD.

Inflammatory Networks in Renal Cell Carcinoma

Cancer-associated inflammation has been established as a hallmark feature of almost all solid cancers. Tumor-extrinsic and intrinsic signaling pathways regulate the process of cancer-associated inflammation. Tumor-extrinsic inflammation is triggered by many factors, including infection, obesity, autoimmune disorders, and exposure to toxic and radioactive substances. Intrinsic inflammation can be induced by genomic mutation, genome instability and epigenetic remodeling in cancer cells that promote immunosuppressive traits, inducing the recruitment and activation of inflammatory immune cells. In RCC, many cancer cell-intrinsic alterations are assembled, upregulating inflammatory pathways, which enhance chemokine release and neoantigen expression. Furthermore, immune cells activate the endothelium and induce metabolic shifts, thereby amplifying both the paracrine and autocrine inflammatory loops to promote RCC tumor growth and progression. Together with tumor-extrinsic inflammatory factors, tumor-intrinsic signaling pathways trigger a Janus-faced tumor microenvironment, thereby simultaneously promoting or inhibiting tumor growth. For therapeutic success, it is important to understand the pathomechanisms of cancer-associated inflammation, which promote cancer progression. In this review, we describe the molecular mechanisms of cancer-associated inflammation that influence cancer and immune cell functions, thereby increasing tumor malignancy and anti-cancer resistance. We also discuss the potential of anti-inflammatory treatments, which may provide clinical benefits in RCCs and possible avenues for therapy and future research.

Nc886 promotes renal cancer cell drug-resistance by enhancing EMT through Rock2 phosphorylation-mediated β-catenin nuclear translocation

Drug resistance is a significant challenge in the present treatment regimens of renal cell carcinoma (RCC). Our previous study confirmed that nc886 functions as an oncogene in RCC. Nevertheless, the role and underlying mechanism of nc886 in RCC drug resistance are unclear. In the present study, Sunitinib and Everolimus treatment, respectively, downregulated nc886 expression in a dose-dependent manner in all four renal cancer cell lines. Nc886 overexpression in 786-O cells and ACHN cells significantly reduced the sensitivity of cancer cells to both Sunitinib and Everolimus treatment, respectively, by promoting cell viability and inhibiting cell apoptosis, whereas nc886 silencing increased cancer cell sensitivity. In renal cancer cell line with the highest drug-resistance, 786-O cells, Sunitinib, or Everolimus treatment enhanced the cellular EMT and was further enhanced by nc886 overexpression while attenuated by nc886 silencing. In 786-O cells, nc886 overexpression significantly promoted EMT, ROCK2 phosphorylation, and β-catenin nucleus translocation under Sunitinib or Everolimus treatment. Moreover, ROCK2 silencing significantly reversed the effects of nc886 overexpression on EMT, ROCK2 phosphorylation, and β-catenin nucleus translocation, as well as drug-resistant renal cancer cell viability and apoptosis. In conclusion, it was demonstrated that nc886 promotes renal cancer cell proliferation, migration, and invasion, as demonstrated previously. nc886 also promotes renal cancer cell drug-resistance to Sunitinib or Everolimus by promoting EMT through Rock2 phosphorylation-mediated nuclear translocation of β-catenin.

Paclitaxel resistance is mediated by NF-κB on mesenchymal primary breast cancer cells

Paclitaxel has been used widely to treat breast cancer and other types of cancer. However, resistance is a major cause of failure for treatment and results in cancer progression. The present study investigated the association between paclitaxel resistance and the mesenchymal phenotype, using a model of primary breast cancer cells and employing four different cultures, two with an epithelial phenotype (MBCDF and MBCD17) and two with a mesenchymal phenotype (MBCDF-D5 and MBCD3). Epithelial-mesenchymal markers were evaluated by western blotting; MBCDF and MBCD17 cells expressed E-cadherin, SNAIL, Slug, and Twist, low levels of N-cadherin, but not vimentin. MBCDF-D5 and MBCD3 cells expressed N-cadherin, vimentin, and higher levels of SNAIL, and low levels of E-cadherin, Slug, and Twist. Cell viability was evaluated using a crystal violet assay after paclitaxel treatment; primary breast cancer cells with mesenchymal phenotype were resistant to paclitaxel compared with the epithelial primary breast cancer cells. Furthermore, using western blotting, it was revealed that mesenchymal cells had elevated levels of nuclear factor-κΒ (NF-κB) p65 and IκB kinase (IKK). Additionally, it was demonstrated that paclitaxel-induced degradation of the inhibitor of NF-κB, activation of NF-κB in a dose-dependent manner, and Bcl-2 and Bcl-xL upregulation. Finally, employing western blotting and crystal violet assays, the effects of the proteasome inhibitor ALLN were assessed. ALLN inhibited paclitaxel-induced NF-κB activation and restored the sensitivity to paclitaxel. Together, these data suggest that targeting the NF-κB/IKK axis might be a promising strategy to overcome paclitaxel resistance.

An experimental model of the epithelial to mesenchymal transition and pro-fibrogenesis in urothelial cells related to bladder pain syndrome/interstitial cystitis

Background

Suitable in vitro models are needed to investigate urothelial epithelial to mesenchymal transition (EMT) and pro-fibrogenesis phenotype in bladder pain syndrome/interstitial cystitis (BPS/IC). This study is to establish a novel experimental BPS/IC cell model and explore how different concentrations of tumor necrosis factor (TNF)-α influence the EMT and pro-fibrogenesis phenotype of urothelial cells.

Methods

SV-HUC-1 urothelial cells were cultured with 2, 10, or 50 ng/mL TNF-α to mimic chronic inflammatory stimulation. The EMT and pro-fibrogenesis phenotype, including production of collagen I and pro-fibrosis cytokines, were estimated after 72 h of culture.

Results

The bladder urothelial cells of BPS/IC exhibited upregulated vimentin, TNF-α and TNF receptor, downregulated E-cadherin, and increased collagen I. Higher concentrations of TNF-α (10 and 50 ng/mL) produced an obvious mesenchymal morphology, enhanced invasion and migratory capacity, increased expression of vimentin, and decreased expression of E-cadherin. Collagen I was increased in cells treated with 2 and 10 ng/mL TNF-α after 72 h. Secretion of interleukin (IL)-6 and IL-8 was promoted with 10 and 50 ng/mL TNF-α, while that of IL-1β or transforming growth factor-β was unaffected. Slug and Smad2 were upregulated by TNF-α after 72 h. The Smad pathway was activated most strongly with 10 ng/mL TNF-α and Slug pathway activation was positively correlated with the concentration of TNF-α.

Conclusions

Sustained 10 ng/mL TNF-α stimulation induced the EMT and pro-fibrogenesis phenotype resembling BPS/IC in SV-HUC-1 cells. Minor inflammatory stimulation induced the pro-fibrogenesis phenotype while severe inflammatory stimulation was more likely to produce significant EMT changes. Different degrees of activation of the Slug and Smad pathways may underlie this phenomenon.

Key genes associated with prognosis and metastasis of clear cell renal cell carcinoma

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is a tumor that frequently shows the hematogenous pathway and tends to be resistant to radiotherapy and chemotherapy. However, the exact mechanism of ccRCC metastasis remains unknown.

METHODS

Differentially expressed genes (DEGs) of three gene expression profiles (GSE85258, GSE105288 and GSE22541) downloaded from the Gene Expression Omnibus (GEO) database were analyzed by GEO2R analysis, and co-expressed DEGs among the datasets were identified using a Venn drawing tool. The co-expressed DEGs were investigated using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, and hub genes were determined based on the protein-protein interaction network established by STRING. After survival analysis performed on UALCAN website, possible key genes were selected and verified in ccRCC cell lines and ccRCC tissues (n = 44). Statistical analysis was conducted using GraphPad Prism (Version 8.1.1).

RESULTS

A total of 104 co-expressed DEGs were identified in the three datasets. Pathway analysis revealed that these genes were enriched in the extracellular matrix (ECM)-receptor interaction, protein digestion and absorption and focal adhesion. Survival analysis on 17 hub genes revealed that four key genes with a significant impact on survival: procollagen C-endopeptidase enhancer (PCOLCE), prolyl 4-hydroxylase subunit beta (P4HB), collagen type VI alpha 2 (COL6A2) and collagen type VI alpha 3 (COL6A3). Patients with higher expression of these key genes had worse survival than those with lower expression. In vitro experiments revealed that the mRNA expression levels of PCOLCE, P4HB and COL6A2 were three times higher and that of COL6A3 mRNA was 16 times higher in the metastatic ccRCC cell line Caki-1 than the corresponding primary cell line Caki-2. Immunohistochemistry revealed higher expression of the proteins encoded by these four genes in metastatic ccRCC compared with tumors from the corresponding primary sites, with statistical significance.

CONCLUSION

PCOLCE, P4HB, COL6A2 and COL6A3 are upregulated in metastatic ccRCC and might be related to poor prognosis and distant metastases.

A Four-MicroRNA Panel in Serum as a Potential Biomarker for Screening Renal Cell Carcinoma

Background: Renal cell carcinoma (RCC) has been a major health problem and is one of the most malignant tumors around the world. Serum microRNA (miRNA) profiles previously have been reported as non-invasive biomarkers in cancer screening. The aim of this study was to explore serum miRNAs as potential biomarkers for screening RCC. Methods: A three-phase study was conducted to explore serum miRNAs as potential biomarkers for screening RCC. In the screening phase, 12 candidate miRNAs related to RCC were selected for further study by the ENCORI database with 517 RCC patients and 71 NCs. A total of 220 participants [108 RCC patients and 112 normal controls (NCs)] were enrolled for training and validation. The dysregulated candidate miRNAs were further confirmed with 30 RCC patients and 30 NCs in the training phase and with 78 RCC patients and 82 NCs in the validation phase. Receiver operating characteristic (ROC) curves and the area under the ROC curve (AUC) were used for assessing the diagnostic value of miRNAs. Bioinformatic analysis and survival analysis were also included in our study. Results: Compared to NCs, six miRNAs (miR-18a-5p, miR-138-5p, miR-141-3p, miR-181b-5p, miR-200a-3p, and miR-363-3p) in serum were significantly dysregulated in RCC patients. A four-miRNA panel was built by combining these candidate miRNAs to improve the diagnostic value with AUC = 0.908. ABCG1 and RNASET2, considered potential target genes of the four-miRNA panel, may play a significant role in the development of RCC. Conclusion: A four-miRNA panel in serum was identified for RCC screening in our study. The four--miRNA panel has a great potential to be a non-invasive biomarker for RCC screening.

CD44 modulates metabolic pathways and altered ROS-mediated Akt signal promoting cholangiocarcinoma progression

CD44 is a transmembrane glycoprotein, the phosphorylation of which can directly trigger intracellular signaling, particularly Akt protein, for supporting cell growth, motility and invasion. This study examined the role of CD44 on the progression of Cholangiocarcinoma (CCA) using metabolic profiling to investigate the molecular mechanisms involved in the Akt signaling pathway. Our results show that the silencing of CD44 decreases Akt and mTOR phosphorylation resulting in p21 and Bax accumulation and Bcl-2 suppression that reduces cell proliferation. Moreover, an inhibition of cell migration and invasion regulated by CD44. Similarly, the silencing of CD44 showed an alteration in the epithelial-mesenchymal transition (EMT), e.g. an upregulation of E-cadherin and a downregulation of vimentin, and the reduction of the matrix metalloproteinase (MMP)-9 signal. Interestingly, a depletion of CD44 leads to metabolic pathway changes resulting in redox status modification and Trolox (anti-oxidant) led to the recovery of the cancer cell functions. Based on our findings, the regulation of CCA progression and metastasis via the redox status-related Akt signaling pathway depends on the alteration of metabolic profiling synchronized by CD44.

lncRNA SNHG1 cooperated with miR-497/miR-195-5p to modify epithelial-mesenchymal transition underlying colorectal cancer exacerbation

Our study was intended to provide evidence for whether long noncoding RNA (lncRNA) SNHG1 would accelerate the epithelial-mesenchymal transition (EMT) course intrinsic in colorectal cancer (CRC) by sponging downstream miR-497-5p and miR-195-5p. We altogether collected 338 pairs of CRC and noncancerous tissues, and meanwhile purchased five CRC cell lines (i.e., SW480, HCT116, Lovo, CaCO-2, and HT29) and human embryo intestinal mucosal tissue-sourced cell line (i.e., CCC-HIE-2). The CRC cells as mentioned above were appraised regarding their potencies in proliferation, migration, and invasion, after being transfected with pcDNA3.1-SNHG1, si-SNHG1, miR-195-5p mimic/inhibitor, and miR-497-5p mimic/inhibitor. Eventually, we depended on reverse transcription-polymerase chain reaction to assess SNHG1, miR-497-5p, and miR-195-5p expressions, and the protein levels of EMT-specific molecules were determined on the strength of western blotting. It seemed that there was a high potential for highly expressed SNHG1 and lowly expressed miR-497/miR-195 to symbolize CRC patients' unfavorable prognosis (p < .05). Concurrently, CRC cells were detected with higher SNHG1 expression and lower miR-497/miR-195 expression than CCC-HIE-2 cells (p < .05). In addition, the EMT process of CRC cells was facilitated markedly against the contexts of overexpressed SNHG1 and underexpressed miR-497-5p/miR-195-5p. Intriguingly, the strength of miR-195-5p collaborating with miR-497-5p in affecting the activity of CRC cells seemed to overweigh that of miR-497/miR-195-5p alone. Besides, both miR-195-5p and miR-497-5p were subjected to in vivo and in vitro modification of SNHG1 (p < .05). Conclusively, application of lncRNA SNHG1 for treating CRC might be promising, given its dual modulation of miR-497 and miR-195 underlying CRC pathogenesis.

MicroRNA-506 inhibits tumor growth and metastasis in nasopharyngeal carcinoma through the inactivation of the Wnt/β-catenin signaling pathway by down-regulating LHX2

Background

Epithelial-mesenchymal transition (EMT)-associated proteins play key roles in cancer progression and metastasis with the involvement of microRNAs (miRNAs). This study aims to assess the role of miR-506 working in tandem with LIM Homeobox 2 (LHX2) in EMT and metastasis through the Wnt/β-catenin signaling pathway in nasopharyngeal carcinoma (NPC).

Methods

Differentially expressed genes associated with NPC were screened using microarray analyses, from which LHX2 was identified. Next, the potential relationship between miR-506 and LHX2 was analyzed. In order to explore the effect of miR-506 or LHX2 on NPC cell proliferation, migration, invasion and apoptosis, serials of mimics, inhibitors or siRNA against LHX2 were transfected into NPC cells. Then, the expression patterns of LHX2, Wnt1, β-catenin, E-cadherin, Vimentin, TCF4 and Twist were determined to assess the influence of miR-506 or LHX2 on EMT as well as the relationship between the Wnt/β-catenin signaling pathway and TCF4. The tumorigenicity and lymph node metastasis (LNM) in xenograft tumors of nude mice were observed.

Results

The has-miR-506-3p was identified as the down-regulated gene in NPC based on the microarray data while LHX2 was negatively regulated by miR-506. Over-expression of miR-506 or silencing of LHK2 inhibited NPC cell proliferation, migration, invasion, tumorigenicity and LNM but promoted apoptosis indicated by decreased Wnt1, β-catenin, Vimentin, TCF4 and Twist expressions along with increased E-cadherin expressions.

Conclusions

miR-506 inhibits tumor growth and metastasis in NPC via inhibition of Wnt/β-catenin signaling by down-regulating LHX2, accompanied by decreased TCF4. Taken together, miR-506 targeted-inhibition LHX2 presents a promising therapeutic strategy for the treatment of NPC.

Trial registration

ChiCTR1800018889. Registered 15 October 2018.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1023-4) contains supplementary material, which is available to authorized users.

Protective effect of ginsenoside Rg1 on LPS-induced apoptosis of lung epithelial cells

Sepsis-induced acute lung injury (ALI) is a life-threatening medical condition with high mortality and morbidity in the critical care units. Though, it was commonly accepted that inflammation and apoptosis of lung epithelial cells played an essential role in the pathogenesis of ALI, the underlying mechanism remain unknown. In our study, we found that LPS-induced cell apoptosis could be counteracted by elevated cell autophagy. In LPS-treated MLE-12 cells, suppression of autophagy via 3-MA could aggravate LPS-induced apoptosis, while activation of autophagy via Rapamycin could effectively impair the apoptosis of MLE-12 cells induced by LPS. In order to further discover the molecular regulation mechanism between apoptosis and autophagy in LPS-treated MLE-12 cells, we demonstrated that autophagy could induced the expression of Nrf2, followed with the decrease of p-p65. Targeted inhibition of Nrf2 could induce enlarged cell apoptosis via increasing the level of p-p65. In addition, we demonstrated that ginsenoside Rg1 protected MLE-12 cells from LPS-induced apoptosis via augmenting autophagy and inducing the expression of Nrf2. Our data implicates that activation of autophagy and Nrf2 by ginsenoside Rg1 may provide a preventive and therapeutic strategy for ALI.

Effect of Stromal Cells in Tumor Microenvironment on Metastasis Initiation

The cellular environment where tumor cells reside is called the tumor microenvironment (TME), which consists of borders, blood vessels, lymph vessels, extracellular matrix (ECM), stromal cells, immune/inflammatory cells, secreted proteins, RNAs and small organelles. By dynamically interacting with tumor cells, stromal cells participate in all stages of tumor initiation, progression, metastasis, recurrence and drug response, and consequently, affect the fate of patients. During the processes of tumor evolution and metastasis initiation, stromal cells in TME also experience some changes and play roles in both the suppression and promotion of metastasis, while the overall function of stromal cells is beneficial for cancer cell survival and movement. In this review, we examine the effects of stromal cells in TME on metastasis initiation, including angiogenesis, epithelial-mesenchymal transition (EMT) and invasion. We also highlight functions of proteins, RNAs and small organelles secreted by stromal cells in their influences on multiple stages of tumor metastasis.

Reduction of Membrane Protein CRIM1 Decreases E-Cadherin and Increases Claudin-1 and MMPs, Enhancing the Migration and Invasion of Renal Carcinoma Cells

CRIM1 is a membrane protein that has been reported to be related to cell proliferation. CRIM1 is expressed in renal carcinoma cells, but its involvement in proliferation and malignant transformation remains unclear. We analyzed whether alterations in the characteristics of cancer cells are observed following knockdown of CRIM1. Decreased expression of CRIM1 did not affect proliferation or anchorage-independent growth. The results of wound healing and invasion assays showed that reduced expression of CRIM1 increased cells' migratory and invasive abilities. Expression analysis of factors involved in migration and invasion in CRIM1-knockdown cells revealed that expression of the cell adhesion factor E-cadherin declined and expression of claudin-1, which is upregulated in metastatic cancer cells, increased. In addition, increased expression of matrix metalloproteinase (MMP) 2 and MMP9, protease essential for cancer cell invasiveness, was observed. Furthermore, an increase in phosphorylated focal adhesion kinase (FAK), which increases cell migration, was observed. Increased expression of the E-cadherin transcription repressors Snail, Slug, and ZEB-1 were observed, and mRNA levels of E-cadherin were decreased. Therefore, expression of E-cadherin is thought to be decreased by both suppression of E-cadherin mRNA expression and promotion of degradation of the E-cadherin protein. In addition, expression of CRIM1 was decreased in renal cancer cells undergoing epithelial-mesenchymal transition (EMT) stimulated by tumor necrosis factor alpha (TNF-α). Thus, CRIM1 regulates the expression of several EMT-related factors and appears to play a role in suppressing migration and invasion through control of EMT.

Cadherin-6B proteolytic N-terminal fragments promote chick cranial neural crest cell delamination by regulating extracellular matrix degradation

During epithelial-to-mesenchymal transitions (EMTs), chick cranial neural crest cells simultaneously delaminate from the basement membrane and segregate from the epithelia, in part, via multiple protease-mediated mechanisms. Proteolytic processing of Cadherin-6B (Cad6B) in premigratory cranial neural crest cells by metalloproteinases not only disassembles cadherin-based junctions but also generates shed Cad6B ectodomains or N-terminal fragments (NTFs) that may possess additional roles. Here we report that Cad6B NTFs promote delamination by enhancing local extracellular proteolytic activity around neural crest cells undergoing EMT en masse. During EMT, Cad6B NTFs of varying molecular weights are observed, indicating that Cad6B may be cleaved at different sites by A Disintegrin and Metalloproteinases (ADAMs) 10 and 19 as well as by other matrix metalloproteinases (MMPs). To investigate Cad6B NTF function, we first generated NTF constructs that express recombinant NTFs with similar relative mobilities to those NTFs shed in vivo. Overexpression of either long or short Cad6B NTFs in premigratory neural crest cells reduces laminin and fibronectin levels within the basement membrane, which then facilitates precocious neural crest cell delamination. Zymography assays performed with supernatants of neural crest cell explants overexpressing Cad6B long NTFs demonstrate increased MMP2 activity versus controls, suggesting that Cad6B NTFs promote delamination through a mechanism involving MMP2. Interestingly, this increase in MMP2 does not involve up-regulation of MMP2 or its regulators at the transcriptional level but instead may be attributed to a physical interaction between shed Cad6B NTFs and MMP2. Taken together, these results highlight a new function for Cad6B NTFs and provide insight into how cadherins regulate cellular delamination during normal developmental EMTs as well as aberrant EMTs that underlie human disease.

Differential expression profile of CXCR3 splicing variants is associated with thyroid neoplasia. Potential role in papillary thyroid carcinoma oncogenesis?

Papillary thyroid cancer (PTC) is the most prevalent endocrine neoplasia. The increased incidence of PTC in patients with thyroiditis and the frequent immune infiltrate found in PTC suggest that inflammation might be a risk factor for PTC development. The CXCR3-ligand system is involved in thyroid inflammation and CXCR3 has been found upregulated in many tumors, suggesting its pro-tumorigenic role under the inflammatory microenvironment. CXCR3 ligands (CXCL4, CXCL9, CXCL10 and CXCL11) trigger antagonistic responses partly due to the presence of two splice variants, CXCR3A and CXCR3B. Whereas CXCR3A promotes cell proliferation, CXCR3B induces apoptosis. However, the relation between CXCR3 variant expression with chronic inflammation and PTC development remains unknown. Here, we characterized the expression pattern of CXCR3 variants and their ligands in benign tumors and PTC. We found that CXCR3A and CXCL10 mRNA levels were increased in non-metastatic PTC when compared to non-neoplastic tissue. This increment was also observed in a PTC epithelial cell line (TPC-1). Although elevated protein levels of both isoforms were detected in benign and malignant tumors, the CXCR3A expression remained greater than CXCR3B and promoted proliferation in Nthy-ori-3-1 cells. In non-metastatic PTC, inflammation was conditioning for the CXCR3 ligands increased availability. Consistently, CXCL10 was strongly induced by interferon gamma in normal and tumor thyrocytes.

Our results suggest that persistent inflammation upregulates CXCL10 expression favoring tumor development via enhanced CXCR3A-CXCL10 signaling. These findings may help to further understand the contribution of inflammation as a risk factor in PTC development and set the basis for potential therapeutic studies.

Role of tumor necrosis factor-α in epithelial-to-mesenchymal transition in transplanted kidney cells in recipients with chronic allograft dysfunction

BACKGROUND

Chronic allograft dysfunction (CAD) is characterized by allograft kidney interstitial fibrosis, the underlying mechanism of which is unclear. Our aim was to elucidate the role and mechanism of TNF-α-induced epithelial-to-mesenchymal transition (EMT) in transplant kidney tubular interstitial fibrosis.

METHODS

Human kidney tissues from normal volunteers and CAD patients were assessed using periodic acid-Schiff, Masson trichrome and immunohistochemical staining. mRNA and protein expression of E-cadherin, α-smooth muscle actin (SMA) and fibronectin(FN) in renal proximal tubule epithelial (HK-2) cells after treatment with TNF-α under different conditions were assessed using western blot and qRT-PCR analysis. Cell motility and migration were assessed using wound healing and transwell assays. Expression of Smurf2 and TNF-α-signaling pathway-related proteins in HK-2 cells treated with TNF-α was detected by western blotting. E-cadherin and α-SMA expression was also assessed in Smurf2 plasmid-transfected or Smurf2 siRNA-treated HK-2 cells.

RESULTS

The expression of TNF-α, Smurf2, α-SMA, and fibronectin was significantly upregulated, while the expression of E-cad was downregulated in the CAD group compared with the normal group. The in vitro results showed that TNF-α remarkably upregulated the expression of Smurf2, α-SMA and fibronectin and downregulated the expression of E-cadherin in HK-2 cells and enhanced motility and migration in HK-2 cells. Overexpression of Smurf2 could promote the expression of α-SMA and inhibit the expression of E-cad, whereas knockdown of Smurf2 expression reversed TNF-α-induced upregulation of α-SMA and prohibited the reduction of E-cad expression. Furthermore, TNF-α-induced Smurf2 expression promoted EMT through the Akt signaling pathway.

CONCLUSIONS

TNF-α induced EMT via the TNF-α/Akt/Smurf2 signaling pathways, and it may play a role in aggravating allograft kidney interstitial fibrosis in CAD patients.

The Role of cIAP1 and XIAP in Apoptosis Induced by Tumor Necrosis Factor Alpha in Esophageal Squamous Cell Carcinoma Cells

BACKGROUND

The inhibitor of apoptosis protein (IAP) family are reported to play important roles in cancer cells evading apoptosis. However, the significance of their expression in human esophageal squamous cell carcinoma (ESCC) cells remains uncertain.

AIMS

The present study aimed to investigate the role of the IAP family members in tumor necrosis factor-α (TNF-α)-induced apoptosis of human ESCC cells.

METHODS

Five human ESCC cell lines were pretreated with TNF-α, cycloheximide (CHX, protein synthesis inhibitor), epoxomicin (proteasome inhibitor). Apoptosis assay and protein study with Western blot testing were conducted. Knockdown experiments with IAP siRNA were conducted, and the effect on cell apoptosis was analyzed.

RESULTS

Significant apoptosis was induced in five ESCC cell lines by TNF-α plus CHX stimulation, but not when treated with TNF-α or CHX alone. The protein expression levels of cIAP1 and XIAP were decreased by treatment with TNF-α in the presence of CHX, and the degree of cIAP1 and XIAP expression decrease was correlated with sensitivity to TNF-α plus CHX-induced apoptosis. Epoxomicin suppressed TNF-α plus CHX-induced degradation of survivin, cIAP1, and XIAP, in addition to apoptosis. A caspase inhibitor (z-VAD-fmk) suppressed TNF-α plus CHX-induced apoptosis, but did not suppress degradation of survivin, cIAP1, and XIAP. Furthermore, cIAP1 or XIAP siRNA transfected cells underwent apoptosis in response to treatment with TNF-α alone. Double knockdown of both genes resulted in further increased apoptosis.

CONCLUSION

cIAP1 and XIAP play an essential role in the resistance of ESCC cells against apoptosis.

High-mobility group box 1 is overexpressed in cervical carcinoma and promotes cell invasion and migration in vitro

The present study aimed to investigate the expression of high-mobility group box 1 protein (HMGB1) in cervical carcinoma and explore whether or not HMGB1 promotes cervical carcinoma cell invasion and migration in vitro and the related mechanism. HMGB1, nuclear factor-κB (NF-κB), E-cadherin and N-cadherin protein expression was analyzed in tissues from 48 cervical carcinomas, 51 cervical intraepithelial neoplasia (CIN) and tissues from 24 healthy controls using immunohistochemistry. HeLa cells were treated with different concentrations of HMGB1 (0, 10, 100, and 1,000 ng/ml) at different time-points (0, 24, 48 and 72 h), and changes in cell morphology and biological behaviors were observed. Changes in the expression levels of E-cadherin, N-cadherin, NF-κB and the inhibitor κB (IκB) in the treated cells were detected by western blot analysis and real-time PCR. HMGB1 expression exhibited a gradually increasing trend in the normal cervical tissues, CIN and cervical cancer, and there was statistical significance between the three groups (P<0.05). HMGB1 expression level was associated with FIGO stage, lymph node metastasis and differentiation (P<0.05). HMGB1 expression was positively related to N-cadherin and NF-κB; and HMGB1 had a negative relationship with E-cadherin. HMGB1 stimulation caused HeLa cells to lose cell polarity and transition from epithelial cells into spindle-shaped cells with sparse cell-cell junctions. The expression levels of E-cadherin and IκB in the cytoplasm were reduced, while N-cadherin expression was increased. The level of NF-κB expression in the nucleus was also increased. Treatment with NF-κB inhibitor (BAY11-7082) and receptor for advanced glycation end products (RAGE) antagonist (anti-RAGE) significantly suppressed HMGB1‑mediated epithelial-to-mesenchymal transition in the HeLa cervical cancer cells. The results suggest that HMGB1 is associated with outcomes of cervical cancer and promotes subsequent invasion and metastasis of cervical cancer cells by activating the NF-κB signaling pathway. This potential mechanism could be an important determinant of cervical cancer metastasis.

Comparative Gene Expression Profiling of Primary and Metastatic Renal Cell Carcinoma Stem Cell-Like Cancer Cells

Background

Recent advancement in cancer research has shown that tumors are highly heterogeneous, and multiple phenotypically different cell populations are found in a single tumor. Cancer development and tumor growth are driven by specific types of cells—stem cell-like cancer cells (SCLCCs)—which are also responsible for metastatic spread and drug resistance. This research was designed to verify the presence of SCLCCs in renal cell cancer cell lines. Subsequently, we aimed to characterize phenotype and cell biology of CD105+ cells, defined previously as renal cell carcinoma tumor-initiating cells. The main goal of the project was to describe the gene-expression profile of stem cell-like cancer cells of primary tumor and metastatic origin.

Materials and Methods

Real-time PCR analysis of stemness genes (Oct-4, Nanog and Ncam) and soft agar colony formation assay were conducted to check the stemness properties of renal cell carcinoma (RCC) cell lines. FACS analysis of CD105+ and CD133+ cells was performed on RCC cells. Isolated CD105+ cells were verified for expression of mesenchymal markers—CD24, CD146, CD90, CD73, CD44, CD11b, CD19, CD34, CD45, HLA-DR and alkaline phosphatase. Hanging drop assay was used to investigate CD105+ cell-cell cohesion. Analysis of free-floating 3D spheres formed by isolated CD105+ was verified, as spheres have been hypothesized to contain undifferentiated multipotent progenitor cells. Finally, CD105+ cells were sorted from primary (Caki-2) and metastatic (ACHN) renal cell cancer cell lines. Gene-expression profiling of sorted CD105+ cells was performed with Agilent’s human GE 4x44K v2 microarrays. Differentially expressed genes were further categorized into canonical pathways. Network analysis and downstream analysis were performed with Ingenuity Pathway Analysis.

Results

Metastatic RCC cell lines (ACHN and Caki-1) demonstrated higher colony-forming ability in comparison to primary RCC cell lines. Metastatic RCC cell lines harbor numerous CD105+ cell subpopulations and have higher expression of stemness genes (Oct-4 and Nanog). CD105+ cells adopt 3D grape-like floating structures under handing drop conditions. Sorted CD105+ cells are positive for human mesenchymal stem cell (MSC) markers CD90, CD73, CD44, CD146, and alkaline phosphatase activity, but not for CD24 and hematopoietic lineage markers CD34, CD11b, CD19, CD45, and HLA-DR. 1411 genes are commonly differentially expressed in CD105+ cells (both from primary [Caki-2] and metastatic RCC [ACHN] cells) in comparison to a healthy kidney epithelial cell line (ASE-5063). TGF-β, Wnt/β-catenine, epithelial-mesenchymal transition (EMT), Rap1 signaling, PI3K-Akt signaling, and Hippo signaling pathway are deregulated in CD105+ cells. TGFB1, ERBB2, and TNF are the most significant transcriptional regulators activated in these cells.

Conclusions

All together, RCC-CD105+ cells present stemlike properties. These stem cell-like cancer cells may represent a novel target for therapy. A unique gene-expression profile of CD105+ cells could be used as initial data for subsequent functional studies and drug design.

The Rho guanine nucleotide exchange factor ARHGEF5 promotes tumor malignancy via epithelial-mesenchymal transition

Epithelial tumor cells often acquire malignant properties, such as invasion/metastasis and uncontrolled cell growth, by undergoing epithelial–mesenchymal transition (EMT). However, the mechanisms by which EMT contributes to malignant progression remain elusive. Here we show that the Rho guanine nucleotide exchange factor (GEF) ARHGEF5 promotes tumor malignancy in a manner dependent on EMT status. We previously identified ARHGEF5, a member of the Dbl family of GEFs, as a multifunctional mediator of Src-induced cell invasion and tumor growth. In the present study, ARHGEF5 was upregulated during tumor growth factor-β-induced EMT in human epithelial MCF10A cells, and promoted cell migration by activating the Rho-ROCK pathway. ARHGEF5 was necessary for the invasive and in vivo metastatic activity of human colorectal cancer HCT116 cells. These findings underscore the crucial role of ARHGEF5 in cell migration and invasion/metastasis. An in vivo tumorigenesis assay revealed that ARHGEF5 had the potential to promote tumor growth via the phosphatidylinositol 3-kinase (PI3K) pathway. However, ARHGEF5 was not required for tumor growth in epithelial-like human colorectal cancer HCT116 and HT29 cells, whereas the growth of mesenchymal-like SW480 and SW620 cells depended on ARHGEF5. Induction of EMT by tumor necrosis factor-α or Slug in HCT116 cells resulted in the dependence of tumor growth on ARHGEF5. In these mesenchymal-like cells, Akt was activated via ARHGEF5 and its activity was required for tumor growth. Analysis of a transcriptome data set revealed that the combination of ARHGEF5 upregulation and E-cadherin downregulation or Snail upregulation was significantly correlated with poor prognosis in patients with colorectal cancers. Taken together, our findings suggest that EMT-induced ARHGEF5 activation contributes to the progression of tumor malignancy. ARHGEF5 may serve as a potential therapeutic target in a subset of malignant tumors that have undergone EMT.

TNF-α augments CXCR2 and CXCR3 to promote progression of renal cell carcinoma

Within the tumour microenvironment, a complex network of chemokines and their receptors affects the initiation and progression of tumours. The higher levels of tumour necrosis factor‐alpha (TNF‐α) are associated with tumour progression and an anti‐TNF‐α monoclonal antibody has been used successfully to treat patients with renal cell carcinoma (RCC). However, the role of chemokines and their receptors in the TNF‐α‐promoted progression of RCC remains unclear. In this study, TNF‐α was found to enhance the migration, invasion and epithelial‐mesenchymal transition (EMT) of RCC cells. To further investigate the molecular mechanism of TNF‐α on the progression of RCC, reverse transcription and quantitative PCR was used to screen chemokines and chemokine receptors that were associated with tumorigenesis. The results showed that TNF‐α significantly increased the expressions of CXCR2 and CXCR3 and their related ligands in RCC cells. Subsequently, we used a lentiviral shRNA system to knockdown the expression of CXCR2 and/or CXCR3 in RCC cells. CXCR2 and CXCR3 silencing inhibited the induction of Slug and ZEB‐1 with TNF‐α treatment of RCC cells. In addition, the knockdown of both CXCR2 and CXCR3 resulted in a greater decrease in cell migration, invasion and clonogenic ability compared with either CXCR2 or CXCR3 knockdown alone. Moreover, CXCR2 and CXCR3 silencing significantly reduced the sphere‐forming ability of RCC cells. High expression levels of CXCR2 and CXCR3 in cancer tissues correlated with tumour progression of renal cell carcinoma. These findings suggest that TNF‐α augments CXCR2 and CXCR3 to promote the progression of renal cell carcinoma leading to a poor prognosis.

Gene set enrichment analysis and ingenuity pathway analysis of metastatic clear cell renal cell carcinoma cell line

In recent years, genome-wide RNA expression analysis has become a routine tool that offers a great opportunity to study and understand the key role of genes that contribute to carcinogenesis. Various microarray platforms and statistical approaches can be used to identify genes that might serve as prognostic biomarkers and be developed as antitumor therapies in the future. Metastatic renal cell carcinoma (mRCC) is a serious, life-threatening disease, and there are few treatment options for patients. In this study, we performed one-color microarray gene expression (4×44K) analysis of the mRCC cell line Caki-1 and the healthy kidney cell line ASE-5063. A total of 1,921 genes were differentially expressed in the Caki-1 cell line (1,023 upregulated and 898 downregulated). Gene Set Enrichment Analysis (GSEA) and Ingenuity Pathway Analysis (IPA) approaches were used to analyze the differential-expression data. The objective of this research was to identify complex biological changes that occur during metastatic development using Caki-1 as a model mRCC cell line. Our data suggest that there are multiple deregulated pathways associated with metastatic clear cell renal cell carcinoma (mccRCC), including integrin-linked kinase (ILK) signaling, leukocyte extravasation signaling, IGF-I signaling, CXCR4 signaling, and phosphoinositol 3-kinase/AKT/mammalian target of rapamycin signaling. The IPA upstream analysis predicted top transcriptional regulators that are either activated or inhibited, such as estrogen receptors, TP53, KDM5B, SPDEF, and CDKN1A. The GSEA approach was used to further confirm enriched pathway data following IPA.

Epithelial-mesenchymal transition, inflammatory bowel disease and colitis associated colorectal cancer

Chronic inflammation can induce the formation of a wide variety of tumors. Inflammatory bowel disease is one of the major risk factors for colorectal cancer. Epithelial-mesenchymal transition (EMT) can promote the invasion and metastasis of a variety of cancer cells, including colorectal cancer cells. Different kinds of inflammatory cytokines produced in inflammatory bowel disease could mediate the activation of EMT through a series of pathways, and thus promote the occurrence and development of colitis associated colorectal cancer. This article explores the relationship among EMT, inflammatory bowel disease and colitis associated colorectal cancer, with an aim to provide new ideas and methods for the clinical treatment of colitis associated colorectal cancer.

Twist1 regulates the epithelial-mesenchymal transition via the NF-κB pathway in papillary thyroid carcinoma

Expression of the oncogene Twist1 is correlated with tumor development and metastasis. Recent studies have suggested that the epithelial-to-mesenchymal transition (EMT) is necessary for tumor progression and metastases. Little is known concerning the role of Twist1 and EMT in thyroid cancer. In the present work, the expression levels of Twist1 and one marker of EMT, vimentin, were measured in papillary thyroid carcinoma (PTC). The results showed Twist1 expression to be correlated only with cancer lymph node metastases (P = 0.004) and not with other clinicopathological indicators. Moreover, Twist1 expression was positively correlated with the expression of vimentin (r = 0.408, P = 0.003). In vitro studies further indicated that reducing Twist1 expression using short hairpin RNA against Twist1 can decrease the invasive and metastatic properties of PTC cells and that the down-regulation of Twist1 can reverse EMT by increasing the expression of E-cadherin and down-regulating the expression of vimentin in the PTC cell line IHH-4. To investigate the effects on Twist1, the PTC cell lines TPC-1 and BCPAP were treated with TNF-α, resulting in Twist1 up-regulation that was dependent on NF-κB activation. After the inhibition of NF-κB activity with Bay11-7082, the Twist1 mRNA and protein levels could not be increased. The decline in the Twist1 mRNA and protein levels rendered the cancer cells less invasive. Thus, we conclude that Twist1 plays an important role in the EMT of PTC via the NF-κB pathway.

The Inflammatory Transcription Factors NFκB, STAT1 and STAT3 Drive Age-Associated Transcriptional Changes in the Human Kidney

Human kidney function declines with age, accompanied by stereotyped changes in gene expression and histopathology, but the mechanisms underlying these changes are largely unknown. To identify potential regulators of kidney aging, we compared age-associated transcriptional changes in the human kidney with genome-wide maps of transcription factor occupancy from ChIP-seq datasets in human cells. The strongest candidates were the inflammation-associated transcription factors NFκB, STAT1 and STAT3, the activities of which increase with age in epithelial compartments of the renal cortex. Stimulation of renal tubular epithelial cells with the inflammatory cytokines IL-6 (a STAT3 activator), IFNγ (a STAT1 activator), or TNFα (an NFκB activator) recapitulated age-associated gene expression changes. We show that common DNA variants in RELA and NFKB1, the two genes encoding subunits of the NFκB transcription factor, associate with kidney function and chronic kidney disease in gene association studies, providing the first evidence that genetic variation in NFκB contributes to renal aging phenotypes. Our results suggest that NFκB, STAT1 and STAT3 underlie transcriptional changes and chronic inflammation in the aging human kidney.

The structure and function of human kidneys deteriorate steadily with age, yet little is known about the underlying causes of kidney aging. In this work, we first used a genomics approach to identify candidate regulators of gene expression changes in the aging human kidney and identified inflammation-related transcription factors NFκB, STAT1 and STAT3 as the top candidate regulators. We found that kidney aging is associated with activation of NFκB, STAT1 and STAT3 in the renal parenchyma, and that the gene expression signatures evoked by activation of these transcription factors in human renal epithelial cells mimics age-associated gene expression changes in the kidney. Furthermore, we identified specific genetic variants in the NFκB transcription factor genes RELA and NFKB1 that associate with renal function and chronic kidney disease in humans, implicating NFκB as a potential contributor to the pathogenesis of chronic kidney disease and renal dysfunction in old age. Our findings suggest that activation of the inflammatory transcription factors STAT1, STAT3 and NFκB underlie transcriptional changes and reduced renal function in the elderly.

Characterization of clear cell renal cell carcinoma by gene expression profiling

OBJECTIVES

Use global gene expression to characterize differences between high-grade and low-grade clear cell renal cell carcinoma (ccRCC) compared with normal and benign renal tissue.

METHODS

Tissue samples were collected from patients undergoing surgical resection for ccRCC. Affymetrix gene expression arrays were used to examine global gene expression patterns in high- (n = 16) and low-grade ccRCC (n = 13) as well as in samples from normal kidney (n =14) and benign kidney disease (n = 6). Differential gene expression was determined by analysis of variance with a false discovery rate of 1% and a 2-fold cutoff.

RESULTS

Comparing high-grade ccRCC with each of normal and benign kidney resulted in 1,833 and 2,208 differentially expressed genes, respectively. Of these, 930 were differentially expressed in both comparisons. In order to identify genes most related to progression of ccRCC, these differentially expressed genes were filtered to identify genes that showed a pattern of expression with a magnitude of change greater in high-grade ccRCC in the comparison to low-grade ccRCC. This resulted in the identification of genes such as TMEM45A, ceruloplasmin, and E-cadherin that were involved in cell processes of cell differentiation and response to hypoxia. Additionally changes in HIF1α and TNF signaling are highly represented by changes between high- and low-grade ccRCC.

CONCLUSIONS

Gene expression differences between high-grade and low-grade ccRCC may prove to be valuable biomarkers for advanced ccRCC. In addition, altered signaling between grades of ccRCC may provide important insight into the biology driving the progression of ccRCC and potential targets for therapy.

Potentiating effects of GHRH analogs on the response to chemotherapy

Growth hormone releasing hormone (GHRH) from hypothalamus nominatively stimulates growth hormone release from adenohypophysis. GHRH is also produced by cancers, acting as an autocrine/paracrine growth factor. This growth factor function is seen in lymphoma, melanoma, colorectal, liver, lung, breast, prostate, kidney, bladder cancers. Pituitary type GHRH receptors and their splice variants are also expressed in these malignancies. Synthetic antagonists of the GHRH receptor inhibit proliferation of cancers. Besides direct inhibitory effects on tumors, GHRH antagonists also enhance cytotoxic chemotherapy. GHRH antagonists potentiate docetaxel effects on growth of H460 non-small cell lung cancer (NSCLC) and MX-1 breast cancer plus suppressive action of doxorubicin on MX-1 and HCC1806 breast cancer. We investigated mechanisms of antagonists on tumor growth, inflammatory signaling, doxorubicin response, expression of drug resistance genes, and efflux pump function. Triple negative breast cancer cell xenografted into nude mice were treated with GHRH antagonist, doxorubicin, or their combination. The combination reduced tumor growth, inflammatory gene expression, drug-resistance gene expression, cancer stem-cell marker expression, and efflux-pump function. Thus, antagonists increased the efficacy of doxorubicin in HCC1806 and MX-1 tumors. Growth inhibition of H460 NSCLC by GHRH antagonists induced marked downregulation in expression of prosurvival proteins K-Ras, COX-2, and pAKT. In HT-29, HCT-116 and HCT-15 colorectal cancer lines, GHRH antagonist treatment caused cellular arrest in S-phase of cell cycle, potentiated inhibition of in vitro proliferation and in vivo growth produced by S-phase specific cytotoxic agents, 5-FU, irinotecan and cisplatin. This enhancement of cytotoxic therapy by GHRH antagonists should have clinical applications.

Unconventional Functions of Mitotic Kinases in Kidney Tumorigenesis

Human tumors exhibit a variety of genetic alterations, including point mutations, translocations, gene amplifications and deletions, as well as aneuploid chromosome numbers. For carcinomas, aneuploidy is associated with poor patient outcome for a large variety of tumor types, including breast, colon, and renal cell carcinoma. The Renal cell carcinoma (RCC) is a heterogeneous carcinoma consisting of different histologic types. The clear renal cell carcinoma (ccRCC) is the most common subtype and represents 85% of the RCC. Central to the biology of the ccRCC is the loss of function of the Von Hippel–Lindau gene, but is also associated with genetic instability that could be caused by abrogation of the cell cycle mitotic spindle checkpoint and may involve the Aurora kinases, which regulate centrosome maturation. Aneuploidy can also result from the loss of cell–cell adhesion and apical–basal cell polarity that also may be regulated by the mitotic kinases (polo-like kinase 1, casein kinase 2, doublecortin-like kinase 1, and Aurora kinases). In this review, we describe the “non-mitotic” unconventional functions of these kinases in renal tumorigenesis.

IL-8, a novel messenger to cross-link inflammation and tumor EMT via autocrine and paracrine pathways (Review)

The epithelial-mesenchymal transition (EMT) is a process through which epithelial cells trans-differentiate and acquire an aggressive mesenchymal phenotype. In tumor cells, EMT is a vital step of tumor progression and metastasis. Amid the increasing interest in tumor EMT, only a few studies focused on the soluble mediators secreted by tumor cells passing through this phenotypic switch. In this review, we focus on the essential role of interleukin-8 (IL-8) signaling for the acquisition and maintenance of tumor EMT via direct and indirect mechanisms. Besides the autocrine loop between IL-8 and tumor cells that have gone through EMT, IL-8 could potentiate adjacent epithelial tumor cells into a mesenchymal phenotype via a paracrine mode. Moreover, understanding the role of IL-8 in EMT will provide insight into the pathogenesis of tumor progression and may facilitate the development of an effective strategy for the prevention and treatment of metastatic cancer.

Roles of layilin in TNF-α-induced epithelial-mesenchymal transformation of renal tubular epithelial cells

BACKGROUND

Tumor necrosis factor (TNF)-α is suggested to induce epithelial-mesenchymal transformation (EMT) of renal tubular epithelial cells that possibly exacerbates renal interstitial fibrosis in glomerulonephritis (GN). We here investigated whether layilin (LAYN), a c-type lectin-homologous protein, was involved in the EMT process.

METHODS

Expression of LAYN was investigated in kidneys of mice administered with TNF-α and in a clear cell renal carcinoma cell line of KMRC-1 stimulated with TNF-α by quantitative polymerase chain reaction (qPCR) and/or western blotting. Expression of LAYN was assessed immunohistochemically in renal biopsy samples of patients with various types of GN. Changes of EMT markers and cell morphology by TNF-α and transforming growth factor (TGF)-β in LAYN-knocked down KMRC-1 cells were investigated by qPCR and immunocytochemistry.

RESULTS

Administration of TNF-α increased expression of LAYN in renal tubular epithelia in mice. TNF-α but not TGF-β increased expression of LAYN in KMRC-1 cells. Renal biopsy samples from the patients with GN showed high expression of LAYN in tubular epithelial cells. TNF-α induced up-regulation of vimentin, down-regulation of E-cadherin, and fibroblast-like morphological change in KMRC-1 cells, indicating occurrence of EMT. These changes were not observed in the LAYN-knocked down cells. In contrast, similarly occurred TGF-β-induced EMT was not affected by the LAYN knockdown.

CONCLUSION

Our data indicate that LAYN is involved in the TNF-α-induced EMT of renal tubular epithelial cells. LAYN may play roles in the generation of renal interstitial fibrosis in GN via TNF-α-induced EMT.

Resveratrol attenuates renal injury and fibrosis by inhibiting transforming growth factor-β pathway on matrix metalloproteinase 7

Renal injury has a strong relationship to the subsequent development of renal fibrosis. In developing renal fibrosis, tubular epithelial cells in the kidney underwent epithelial-mesenchymal transition (EMT). Matrix metalloproteinase 7 (MMP7) was reported to reduce E-cadherin and induce EMT by up-regulation of β-catenin/lymphoid enhancer-binding factor 1 (LEF1) signaling. In this research, we tried to evaluate the role of resveratrol (RSV) on EMT process in renal injury and fibrosis. Human tubular epithelial cell HK-2 cells were treated with aristolochic acid (AAs) and transforming growth factor-β(TGF-β) to induce EMT with or without the administration of RSV. The inhibitory role of RSV on EMT in renal injury and fibrosis was determined by Western blotting, real-time PCR, and immunofluorescence staining. The EMT repressing role of RSV was also evaluated in vivo by renal ischemia-reperfusion (I/R) injury and unilateral ureteral obstruction (UUO) models. The underlying mechanism was investigated by shRNA interfering MMP7 and sirtuin 1 (SIRT1) expression. The results indicated that RSV reversed human kidney 2 (HK-2) cell EMT, renal I/R injury, and renal fibrosis. MMP7 inhibition was responsible for RSV-induced EMT repression. SIRT1 was up-regulated by RSV inhibited TGF-β pathway on MMP7 via deacetylating Smad4. In conclusion, RSV attenuated renal injury and fibrosis by inhibiting EMT process which was attributed to the fact that the up-regulated SIRT1 by RSV deacetylated Smad4 and inhibited MMP7 expression.

Hypertension and Circulating Cytokines and Angiogenic Factors in Patients With Advanced Non-Clear Cell Renal Cell Carcinoma Treated With Sunitinib: Results From a Phase II Trial

BACKGROUND

We evaluated the significance of hypertension developing during vascular endothelial growth factor (VEGF) receptor tyrosine kinase inhibitor (VEGFR-TKI) treatment and a group of cytokines and angiogenic factors (CAFs) in advanced non-clear cell renal cell carcinoma (nccRCC) patients treated with sunitinib in a phase II study.

MATERIALS AND METHODS

Using multiplex assays, we analyzed the levels of 38 CAFs in plasma at baseline and after 4 weeks of sunitinib therapy. Sunitinib benefit was defined as a partial response or stable disease using the Response Evaluation Criteria in Solid Tumors lasting ≥4 months. Cox proportional hazards regression models were used to assess the associations among hypertension, CAFs, and progression-free (PFS) and overall survival (OS).

RESULTS

Fifty-seven patients were evaluable; 53 had baseline CAF levels available. The median PFS and OS were 2.9 months (95% confidence interval [CI], 1.4-5.5) and 16.8 months (95% CI, 10.7-27.4), respectively. Sunitinib benefit was observed in 21 patients (37%). However, 33 patients (60%) developed hypertension during treatment, although no association was found with survival or response. Elevated baseline soluble tumor necrosis factor (TNF) receptor I, interleukin-8, growth-regulated oncogene, transforming growth factor-α, and VEGFR-2 levels were associated with an increased risk of death on multivariate analysis.

CONCLUSION

We found no association between the development of hypertension and survival or sunitinib benefit in advanced nccRCC. TNF and angiogenic/immunomodulatory mediators were identified for evaluation as markers of prognosis and VEGFR-TKI benefit in future studies.

A new role for the PI3K/Akt signaling pathway in the epithelial-mesenchymal transition

Tumor metastasis is not only a sign of disease severity but also a major factor causing treatment failure and cancer-related death. Therefore, studies on the molecular mechanisms of tumor metastasis are critical for the development of treatments and for the improvement of survival. The epithelial-mesenchymal transition (EMT) is an orderly, polygenic biological process that plays an important role in tumor cell invasion, metastasis and chemoresistance. The complex, multi-step process of EMT involves multiple regulatory mechanisms. Specifically, the PI3K/Akt signaling pathway can affect the EMT in a variety of ways to influence tumor aggressiveness. A better understanding of the regulatory mechanisms related to the EMT can provide a theoretical basis for the early prediction of tumor progression as well as targeted therapy.

Inflammatory mediators, tumor necrosis factor-α and interferon-γ, induce EMT in human PTC cell lines

Inflammatory mediators, tumor necrosis factor (TNF)-α and interferon (IFN)-γ, promote adverse outcomes in numerous types of cancer; however, their role in papillary thyroid cancer (PTC) remains unclear. The aim of the present study was to investigate the influence of TNF-α and IFN-γ on the migration, invasion and epithelial-mesenchymal transition (EMT) of the three PTC cell lines, TPC-1, BCPAP and K1. The effect of TNF-α and IFN-γ on cell migration and invasion was assessed by wound-healing and Transwell assays. In addition, the mRNA and protein expression levels of the EMT makers, E-cadherin, N-cadherin and vimentin, were analyzed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunoblot analysis. The wound-healing and Transwell experiments revealed that TNF-α and IFN-γ increased the migratory and invasive behavior of PTC cells (P<0.05). RT-qPCR revealed that TNF-α and IFN-γ downregulated E-cadherin mRNA, while they upregulated N-cadherin and vimentin mRNA expression levels. These results were further confirmed by the immunoblot analysis. The results of the present study suggest that TNF-α and IFN-γ induce EMT and malignant progression in human PTC cells.

Claudin 1 mediates tumor necrosis factor alpha-induced cell migration in human gastric cancer cells

AIM: To investigate the role of claudin 1 in the regulation of genes involved in cell migration and tumor necrosis factor alpha (TNF-α)-induced gene expression in human gastric adenocarcinoma cells.

METHODS: Knockdown experiments were conducted with claudin 1 small interfering RNA (siRNA), and the effects on the cell cycle, apoptosis, migration and invasion were analyzed in human gastric adenocarcinoma MKN28 cells. The gene expression profiles of cells were analyzed by microarray and bioinformatics.

RESULTS: The knockdown of claudin 1 significantly inhibited cell proliferation, migration and invasion, and increased apoptosis. Microarray analysis identified 245 genes whose expression levels were altered by the knockdown of claudin 1. Pathway analysis showed that the top-ranked molecular and cellular function was the cellular movement related pathway, which involved MMP7, TNF-SF10, TGFBR1, and CCL2. Furthermore, TNF- and nuclear frctor-κB were the top-ranked upstream regulators related to claudin 1. TNF-α treatment increased claudin 1 expression and cell migration in MKN28 cells. Microarray analysis indicated that the depletion of claudin 1 inhibited 80% of the TNF-α-induced mRNA expression changes. Further, TNF-α did not enhance cell migration in the claudin 1 siRNA transfected cells.

CONCLUSION: These results suggest that claudin 1 is an important messenger that regulates TNF-α-induced gene expression and migration in gastric cancer cells. A deeper understanding of these cellular processes may be helpful in establishing new therapeutic strategies for gastric cancer.

High-mobility group box 1: a novel inducer of the epithelial-mesenchymal transition in colorectal carcinoma

Proinflammatory cytokine high-mobility group box 1 (HMGB1) mediates critical processes of tumour metastasis. Because the epithelial-to-mesenchymal transition (EMT) is a key player in metastasis, the aim of this study was to determine whether and through which mechanism HMGB1 induces EMT in colorectal carcinoma. The direct treatment of cells with recombinant human HMGB1 induced alterations in the epithelial morphology consistent with the EMT and enhanced cell migration through a process mediated by the receptor for advanced glycation end-products (RAGE). The levels of Snail and phospho-NF-κB were upregulated during the HMGB1-induced EMT, and these effects were reversed by inhibiting Snail and NF-κB. In addition, HMGB1 increased the expression of MMP-7 but not that of MMP-9, and this effect was also regulated by Snail/NF-κB signalling. Collectively, these findings indicate that HMGB1 acts as a potent driver of cancer EMT through the RAGE/Snail/NF-κB signalling pathways accompanied by the activation of MMP-7, thereby suggest the feasibility of targeting HMGB1 for the treatment of tumour metastasis.

TNF receptors: signaling pathways and contribution to renal dysfunction

Tumor necrosis factor (TNF), initially reported to induce tumor cell apoptosis and cachexia, is now considered a central mediator of a broad range of biological activities from cell proliferation, cell death and differentiation to induction of inflammation and immune modulation. TNF exerts its biological responses via interaction with two cell surface receptors: TNFR1 and TNFR2. (TNFRs). These receptors trigger shared and distinct signaling pathways upon TNF binding, which in turn result in cellular outputs that may promote tissue injury on one hand but may also induce protective, beneficial responses. Yet the role of TNF and its receptors specifically in renal disease is still not well understood. This review describes the expression of the TNFRs, the signaling pathways induced by them and the biological responses of TNF and its receptors in various animal models of renal diseases, and discusses the current outcomes from use of TNF biologics and TNF biomarkers in renal disorders.

Role of NF-κB in induction of epithelial-mesenchymal transition, migration and invasion of human colon cancer cells

AIM: To investigate the role of nuclear factor-kappa B (NF-κB) in the induction of epithelial-mesenchymal transition (EMT), migration and invasion of human colon cancer cell line HCT116.

METHODS: HCT116 cells were divided into three groups and treated with 20 ng/mL of tumor necrosis factor-α (TNF-α) (NF-κB activation group), 20 μmol/L of ammonium pyrrolidinedithiocarbamate (PDTC) (NF-κB suppression group), and equal volume of culture medium (control group), respectively. Four days later, cell morphological changes associated with EMT were observed under a phase contrast microscope, and the migration ability and invasiveness were assessed by Transwell chamber assays. The protein expression of p65, P-p65, E-cadherin and N-cadherin was analyzed by Western blot, and the mRNA expression of E-cadherin and N-cadherin was detected by quantitative real-time PCR.

RESULTS: TNF-α up-regulated the expression of P-p65 and N-cadherin, suppressed the expression of E-cadherin, and caused a complete EMT-phenotype, which manifested as the formation of large filopodia-like processes and spindle-cell shape. Also, TNF-α promoted cell invasion and migration. In contrast, PDTC down-regulated the expression of P-p65 and N-cadherin, up-regulated the expression of E-cadherin, inhibited the occurrence of typical EMT phenomenon, and suppressed cell invasion and migration. Compared with the control group, TNF-α group and PDTC group showed significantly different cell invasion (97.75 ± 3.77 vs 118.50 ± 1.95, 51.00 ± 1.83, P < 0.05 for both), cell migration (140.00 ± 4.32 vs 167.00 ± 6.36, 80.00 ± 2.53, P < 0.05 for both), and mRNA expression of N-cadherin (1.00 ± 0.00 vs 3.90 ± 0.47, 0.08 ± 0.02, P < 0.05 for both) and E-cadherin (1.00 ± 0.00 vs 0.26 ± 0.08, 6.03 ± 0.59, P < 0.05 for both).

CONCLUSION: NF-κB induces the occurrence of typical EMT phenomenon and promotes cell invasion and migration in human colon cancer cell line HCT116.

Luteolin protects HUVECs from TNF-α-induced oxidative stress and inflammation via its effects on the Nox4/ROS-NF-κB and MAPK pathways

AIM

Inflammation and oxidative stress are now recognized to be two important contributing factors to the development of atherosclerosis(AS). NADPH oxidase-4 (Nox4)-derived reactive oxygen species(ROS), NF-κB and MAPK play crucial roles in these processes. Luteolin, a flavone rich in many plants, can interrupt the molecular expression and inhibit the progression of inflammation and oxidative stress. The present study was designed to test whether luteolin inhibits TNF-α-induced inflammation and oxidative stress in human umbilical vein endothelial cells(HUVECs) and identify some of the mechanisms underlying these effects.

METHODS

HUVECs were treated with luteolin in the presence/absence of TNF-α. The mechanism of luteolin against TNF-α-induced cell injury was evaluated using Western blotting, real-time RT-PCR and flow cytometry analyses.

RESULTS

Luteolin suppressed the TNF-α-activated ROS generation, as well as the Nox4, p22phox, and ICAM-1 and VCAM-1 expression. Luteolin also enhanced the Bcl-2 and reduced caspase-3, -9 expression in the TNF-α-treated HUVECs. Finally, luteolin inhibited the TNF-α-induced transcriptional activity of NF-κB and p38 in addition to ERK1/2 phosphorylation. The inhibitors and siRNA of Nox4 and NF-κB not only reduced ROS generation, p38, ERK1/2 phosphorylation and the ICAM-1 and VCAM-1 expression, but also enhanced Bcl-2 expression. The inhibitor of p38 had the same effect on the expression of ICAM-1, VCAM-1 and Bcl-2, while the inhibitor of ERK1/2 increased the Bcl-2 expression rather than reducing the ICAM-1 and VCAM-1 expression.

CONCLUSIONS

Luteolin attenuates TNF-α-induced oxidative stress and inflammation via its effects on the Nox4/ROS-NF-κB and MAPK pathways. These results suggest that luteolin may provide a beneficial effect in treating vascular diseases associated with oxidative stress and inflammation.

Antidepressant drugs as a complementary therapeutic strategy in cancer

In the last decade, it has been increasingly recognized that antidepressant drugs may exert a range of effects, in addition to their well-documented ability to modulate neurotransmission. Although as a group they act on monoaminergic systems and receptors in different ways, a number of studies have demonstrated that at least some antidepressants might have other properties in common, including immunomodulatory, cyto/neuroprotective, analgesic and anti-inflammatory activities. These properties are partly related to the influence of antidepressants on glial cell function. Recently, emerging information about the possible anticancer properties of antidepressants has sparked increased interest within scientific community, and there is now evidence that these drugs affect the key cellular mechanisms of carcinogenesis. This review examines the putative cellular targets for the anticancer action of antidepressant drugs, and presents examples of the interaction between antidepressants and anticancer drugs. By reviewing the current state of research in this area, we hope to focus the attention of oncologists and researchers engaged in the study of cancer on the role that antidepressant drugs could play in the complementary therapy of cancer.

HAF drives the switch of HIF-1α to HIF-2α by activating the NF-κB pathway, leading to malignant behavior of T24 bladder cancer cells

Hypoxia is a characteristic feature of solid tumors, leading to malignant behavior. During this process, HIF family members (HIFs) and the NF-κB pathway are activated. In addition, the hypoxia-associated factor (HAF) is reported to participate in the regulation of HIFs. However, the precise relationship among HIFs, HAF and the NF-κB pathway in bladder cancer (BC) remains unknown. In the current investigation, T24 BC cells were exposed to hypoxia, or by plasmid transfection to overexpress HAF or RelA (P65) to demonstrate their roles. The results indicate that hypoxia leads to the elevation of HAF plus activation of the NF-κB pathway, accompanied by the switch of HIF-1α to HIF-2α, resulting in the enhanced ability of malignancy in T24 cells. In order to further demonstrate the significance of this switch, HIF-1α and HIF-2α were co-transfected into T24 cells with HIF-β, respectively. The following results indicate that the T24^hif-2α/β cells show enhanced ability of malignancy, accompanied by the maintenance of stem-cell markers, but the T24^hif-1α/β cells show higher expression of metabolism-related genes. Boyden assays and wound-healing assays indicate the enhanced ability of malignancy for T24^hif-2α/β. Thus, we conclude that on the hypoxic microenvironment, the switching of HIF-1α to HIF-2α, which is driven by HAF through activating the NF-κB pathway, contributes to the malignancy of T24 cells, accompanied by the maintenance of stem-cell markers. This provides us an avenue for understanding the progression of bladder cancer.

Tumor necrosis factor α up-regulates endometrial milk fat globule-epidermal growth factor 8 protein production via nuclear factor κB activation, resulting in cell migration of epithelial cells

OBJECTIVE

To explore the role of tumor necrosis factor (TNF) α, an early embryonic product, on endometrial epithelial cell migration and endometrial milk fat globule-epidermal growth factor 8 protein (MFG-E8) production.

DESIGN

In vitro study.

SETTING

Academic center.

INTERVENTION(S)

Ishikawa cells, used as surrogates for human epithelial cells, were treated with and without TNF-α.

MAIN OUTCOME MEASURE(S)

Effect of TNF-α on intracellular MFG-E8 protein was evaluated with the use of ELISA, Western blot, and subcellular fractionation. Specific inhibitors were used to study TNF-α mechanism of action. Effect of TNF-α on cell migration was studied with the use of a wound healing assay and reorganization of E-cadherin.

RESULT(S)

TNF-α induced: 1) significant up-regulation of MFG-E8 intracellular protein, which was attenuated by pretreatment with a specific inhibitor of nuclear factor κB; 2) increased transcription of MFG-E8 and other proinflammatory factors, such as interleukins 6 and 8, which were suppressed by cotreatment with hCG; and 3) significant cell migration with E-cadherin remodeling, changes associated with subcellular MFG-E8 relocalization.

CONCLUSION(S)

TNF-α up-regulates endometrial epithelial cell migration and MFG-E8 production, which are critical steps required for the endometrial changes during menstrual cycle as well as during embryonic attachment and invasion.

Tumor necrosis factor α induces epithelial-mesenchymal transition and promotes metastasis via NF-κB signaling pathway-mediated TWIST expression in hypopharyngeal cancer

Epithelial-mesenchymal transition (EMT) is an important mechanism in cancer metastasis. Tumor necrosis factor α (TNFα) can induce cancer invasion and metastasis associated with EMT. However, the underlying mechanisms are not entirely clear. Therefore, we investigated whether TNFα has an effect on EMT and invasion and metastasis in human hypopharyngeal cancer FaDu cells, and further explored the potential mechanisms. In the present study, we demonstrated that TNFα induced EMT in FaDu cells and promoted FaDu cell migration and invasion. TNFα-induced EMT was characterized by a change from well organized cell-cell adhesion and cell polarity to loss of cell-cell contacts, cell scattering and increased expression of vimentin and N-cadherin accompanied by a decrease in E-cadherin. Furthermore, we found that p65 translocated to the nucleus after TNFα stimulation and increased the nuclear expression of TWIST. We demonstrated that TNFα treatment also increased the expression of TWIST by activating the NF-κB signaling pathway. While p65 was inhibited by siRNA-65 or BAY11-7082 (inhibitor of NF-κB), TWIST expression was also decreased. Therefore, we conclude that TNFα induces EMT and promotes metastasis via NF-κB signaling pathway-mediated TWIST expression in hypopharyngeal cancer.

Role of complement 3 in TNF-α-induced mesenchymal transition of renal tubular epithelial cells in vitro

Injured renal tubular epithelial cells (RTECs) have been recently thought to directly contribute to the accumulation of myofibroblasts in renal tubulointerstitial fibrosis through a process of epithelial to mesenchymal transition (EMT). However, the factors inducing RTECs to undergo EMT and the underlying mechanisms need to be further elucidated. This study aimed to determine the EMT-inducing activity of proinflammatory cytokine TNF-α and the role for complement 3 (C3) in this activity in an in vitro model of human RTECs (HK-2 cells). Wild type HK-2 cells were treated with TNF-α, IFN-γ or C3a; C3 siRNA- or control siRNA-carrying HK-2 cells were treated with TNF-α. Changes in the cell morphology and phenotype were assessed by microscopy, RT-PCR, western blotting, and immunostaining. TNF-α effectively induced HK-2 cells to express C3 and to transform into morphologically myofibroblast-like cells that lost E-cadherin (a classical epithelial cell marker) expression but acquired alpha-smooth muscle actin (α-SMA, a classical myofibroblast differentiation marker) expression. C3 siRNA robustly attenuated all the morphologic and phenotypic changes induced by TNF-α but the control siRNA showed no effect. Our preliminary observations suggest that TNF-α may induce EMT in RTECs through inducing C3 expression.