Shye-Jye Tang

Tumor-derived tumor necrosis factor-alpha promotes progression and epithelial-mesenchymal transition in renal cell carcinoma cells

Pro‐inflammatory cytokines and chemokines are involved in promoting tumorigenesis by facilitating tumor proliferation and metastasis. The serum levels of interleukin (IL)‐6, IL‐1β, and tumor necrosis factor‐alpha (TNF‐α) are significantly elevated in patients with renal cell carcinoma (RCC). However, the mechanisms of how these cytokines participate in the progression of RCC remains unknown. In the present study, we investigated the effects of tumor‐derived cytokines on invasion and the epithelial‐mesenchymal transition (EMT) of RCC cells. We found that expression of IL‐1β, IL‐6, TNF‐α, hypoxia‐inducible factor‐alpha (HIF‐1α), and matrix metalloproteinase‐2 (MMP2) were significantly elevated in high malignancy A498 cells compared to low malignancy 786‐O cells. The invasion ability of A498 was three‐fold higher than that of 786‐O cells. The invasiveness of 786‐O cells was markedly enhanced by adding conditioned medium derived from A498 cells. This phenomenon was significantly inhibited by immunodepletion of TNF‐α followed by MMP2, IL‐6, or IL‐1β from A498 conditioned medium. Synergistic inhibition was also noted after simultaneous immunodepletion of TNF‐α, IL‐1β, and IL‐6. RCC cell lines with higher malignancy produced more TNF‐α, which was correlated with their stronger invasive ability. The invasiveness of 786‐O cells was significantly promoted by TNF‐α in a dose‐dependent manner. Moreover, TNF‐α induced the EMT of 786‐O cells by repressing E‐cadherin, promoting vimentin expression, and activating MMP9 activity. Our findings demonstrate that pro‐inflammatory cytokines, especially TNF‐α, can enhance invasion and the EMT of renal cancer cells, which provides a therapeutic target to prevent and treat advanced RCC. (Cancer Sci 2008; 99: 905–913)

Galectin-1 promotes lung cancer progression and chemoresistance by upregulating p38 MAPK, ERK and cyclooxygenase-2

Purpose: This study is aimed at investigating the role and novel molecular mechanisms of galectin-1 in lung cancer progression. Experimental Design: The role of galectin-1 in lung cancer progression was evaluated both in vitro and in vivo by short hairpin RNA (shRNA)-mediated knockdown of galectin-1 in lung adenocarcinoma cell lines. To explore novel molecular mechanisms underlying galectin-1–mediated tumor progression, we analyzed gene expression profiles and signaling pathways using reverse transcription PCR and Western blotting. A tissue microarray containing samples from patients with lung cancer was used to examine the expression of galectin-1 in lung cancer. Results: We found overexpression of galectin-1 in non–small cell lung cancer (NSCLC) cell lines. Suppression of endogenous galectin-1 in lung adenocarcinoma resulted in reduction of the cell migration, invasion, and anchorage-independent growth in vitro and tumor growth in mice. In particular, COX-2 was downregulated in galectin-1–knockdown cells. The decreased tumor invasion and anchorage-independent growth abilities were rescued after reexpression of COX-2 in galectin-1–knockdown cells. Furthermore, we found that TGF-β1 promoted COX-2 expression through galectin-1 interaction with Ras and subsequent activation of p38 mitogen-activated protein kinase (MAPK), extracellular signal–regulated kinase (ERK), and NF-κB pathway. Galectin-1 knockdown sensitized lung cancer cells to platinum-based chemotherapy (cisplatin). In addition, galectin-1 and COX-2 expression was correlated with the progression of lung adenocarcinoma, and high clinical relevance of both proteins was evidenced (n = 47). Conclusions: p38 MAPK, ERK, and COX-2 activation are novel mediators for the galectin-1–promoted tumor progression and chemoresistance in lung cancer. Galectin-1 may be an innovative target for combined modality therapy for lung cancer. Clin Cancer Res; 18(15); 4037–47. ©2012 AACR.

IL-27 Directly Restrains Lung Tumorigenicity by Suppressing Cyclooxygenase-2-Mediated Activities

Gene transfer of IL-27 to tumor cells has been proven to inhibit tumor growth in vivo by antiproliferation, antiangiogenesis, and stimulation of immunoprotection. To investigate the nonimmune mechanism of IL-27 that suppresses lung cancer growth, we have established a single-chain IL-27-transduced murine Lewis lung carcinoma (LLC-1) cell line (LLC-1/scIL-27) to evaluate its tumorigenic potential in vivo. Mice inoculated with LLC/scIL-27 displayed retardation of tumor growth. Production of IL-12, IFN-γ, and cytotoxic T cell activity against LLC-1 was manifest in LLC/scIL-27-injected mice. Of note, LLC-1/scIL-27 exhibited decreased expression of cyclooxygenase-2 (COX-2) and PGE2. On the cellular level, the LLC/scIL-27 transfectants had reduced malignancy, including down-regulation of vimentin expression and reduction of cellular migration and invasion. The suppression of tumorigenesis by IL-27 on lung cancer cells was further confirmed by the treatment with rIL-27 on the murine LLC-1 and human non-small cell lung carcinoma (NSCLC) cell lines. PGE2-induced vimentin expression, movement, and invasiveness were also suppressed by the treatment with rIL-27. Our data show that IL-27 not only suppresses expression of COX-2 and PGE2 but also decreases the levels of vimentin and the abilities of cellular migration and invasion. Furthermore, inoculation of LLC/scIL-27 into immunodeficient NOD/SCID mice also exhibited reduced tumor growth. Our data indicate that IL-27-induced nonimmune responses can contribute to significant antitumor effects. Taken together, the results suggest that IL-27 may serve as an effective agent for lung cancer therapy in the future.

TNF-α Induces Epithelial–Mesenchymal Transition of Renal Cell Carcinoma Cells via a GSK3β-Dependent Mechanism

TNF-α is a cytokine with antitumorigenic property. In contrast, low dose, chronic TNF-α production by tumor cells or stromal cells may promote tumor growth and metastasis. Serum levels of TNF-α are significantly elevated in renal cell carcinoma (RCC) patients. Here, we showed that TNF-α induced epithelial–mesenchymal transition (EMT) and promoted tumorigenicity of RCC by repressing E-cadherin, upregulating vimentin, activating MMP9, and invasion activities. In addition, TNF-α treatment inhibited glycogen synthase kinase 3β (GSK-3β) activity through serine-9 phosphorylation mediated by the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathway in RCC cells. Inhibition of PI3K/AKT by LY294002 reactivated GSK-3β and suppressed the TNF-α–induced EMT of RCC cells. Inactivation of GSK-3β by LiCl significantly increased MMP9 activity and EMT of RCC cells. Activation of GSK-3β by transduction of constitutively active GSK-3β into RCC cells suppressed TNF-α–mediated anchorage-independent growth in soft agar and tumorigenicity in nude mice. Overexpression of a kinase-deficient GSK-3β, in contrast, potentiated EMT, anchorage-independent growth and drastically enhanced tumorigenicity in vivo. Most importantly, a 15-fold inactivation of GSK-3β activity, 3-fold decrease of E-cadherin, and 2-fold increase of vimentin were observed in human RCC tumor tissues. These results indicated that inactivation of GSK-3β plays a pivotal role in the TNF-α–mediated tumorigenesis of RCC. Mol Cancer Res; 10(8); 1109–19. ©2012 AACR.

Cold-induced ependymin expression in zebrafish and carp brain: implications for cold acclimation.

Cold acclimation has been suggested to be mediated by alternations in the gene expression pattern in the cold‐adapted fish. To investigate the mechanism of cold acclimation in fish brain at the molecular level, relevant subsets of differentially expressed genes of interest were identified and cloned by the PCR‐based subtraction suppression hybridization. Characterization of the selected cold‐induced cDNA clones revealed one encoding ependymin. This gene was shown to be brain‐specific. The expression of ependymin was induced by a temperature shift from 25°C to 6°C in Cyprinus carpio or 12°C in Danio rerio. Activation of ependymin was detected 2 h after cold exposure and peaked at more than 10‐fold at 12 h. This peak level remains unchanged until the temperature returns to 25°C. Although the amount of soluble ependymin protein in brain was not changed by cold treatment, its level in the fibrous insoluble polymers increased 2‐fold after exposure to low temperature. These findings indicate that the increase in ependymin expression is an early event that may play an important role in the cold acclimation of fish.

Autocrine CCL2 promotes cell migration and invasion via PKC activation and tyrosine phosphorylation of paxillin in bladder cancer cells

The amount of monocyte chemoattractant protein-1 (MCP-1/CCL2) produced by a transitional cell carcinoma is directly correlated with high recurrence and poor prognosis in bladder cancer. However, the mechanisms underlying the effects of CCL2 on tumor progression remain unexplored. To investigate the role played by CCL2, we examined cell migration in various bladder cancer cell lines. We found that high-grade cancer cells expressing high levels of CCL2 showed more migration activity than low-grade bladder cancer cells expressing low levels of the chemokine. Although the activation of CCL2/CCR2 signals did not appreciably affect cell growth, it mediated cell migration and invasion via the activation of protein kinase C and phosphorylation of tyrosine in paxillin. Blocking CCL2 and CCR2 with small hairpin RNA (shCCL2) or a specific inhibitor reduced CCL2/CCR2-mediated cell migration. The antagonist of CCR2 promoted the survival of mice bearing MBT2 bladder cancer cells, and CCL2-depleted cells showed low tumorigenicity compared with shGFP cells. In addition to observing high-levels of CCL2 in high-grade human bladder cancer cells, we showed that the CCL2/CCR2 signaling pathway mediated migratory and invasive activity, whereas blocking the pathway decreased migration and invasion. In conclusion, high levels of CCL2 expressed in bladder cancer mediates tumor invasion and is involved with advanced tumorigenesis. Our findings suggest that this CCL2/CCR2 pathway is a potential candidate for the attenuation of bladder cancer metastases.

Transgenic overexpression of anti-double-stranded DNA autoantibody and activation of Toll-like receptor 4 in mice induce severe systemic lupus erythematosus syndromes

Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disease characteristized by the presence of autoantibodies against double-stranded DNA (anti-dsDNA) in sera at high levels. Bacterial infections in SLE are associated with higher morbidity and mortality. Our goal was to observe the interaction between these 2 factors in the pathogenesis of lupus. We generated transgenic mice with monoclonal anti-dsDNA to investigate the development of lupus. By challenging the mice in vitro and in vivo with Toll-like receptor 4 (TLR4) ligand lipopolysaccharides (LPS), we were able to examine the role of bacterial infection in SLE. In our study, the transgenic mice with a secreted form of anti-dsDNA were found to have higher levels of anti-nuclear antibodies, anti-dsDNA, blood urea nitrogen, and proteinuria. The splenocytes of the mice stimulated with LPS secreted more anti-dsDNA, IFN-γ, and IL-10. After injecting them with LPS in vivo, we further found higher immune complex depositions and IL-10 in the kidneys of the transgenic mice. Moreover, the LPS-injected transgenic mice had higher mortality rate. This is the first transgenic model to demonstrate that only 2 risk factors, pathogenic anti-dsDNA and TLR4 activation, induce severe SLE syndromes in normal mice through the overproduction of IL-10 and IFN-γ. These findings imply that anti-dsDNA and bacterial infections have pivotal roles in the pathogenesis of SLE; the inhibition of TLR4 may be regarded as a therapeutic target.

Arginines in the CDR of anti-dsDNA autoantibodies facilitate cell internalization via electrostatic interactions

Internalization of autoantibodies against double‐stranded DNA (anti‐dsDNA) is crucial to the pathogenesis of systemic lupus erythematosus. Anti‐dsDNA may bind to cell‐surface targets in order to facilitate the subsequent cell penetration of the anti‐dsDNA. In this study, we observed that the 9D7 monoclonal anti‐dsDNA autoantibody (9D7 mAb) penetrates into Jurkat cells via a novel alternative pathway. Endocytosis inhibitors or a lipid‐raft inhibitor did not significantly change the penetration of 9D7 mAb into the Jurkat cells. However, heparin sulfate, chondroitin sulfate B, decaarginine and chondroitinase ABC significantly suppressed the internalization and the 9D7 mAb inhibited the internalization of Tat‐GFP. Moreover, the penetration of the 9D7 mAb was significantly reduced in proteoglycan‐deficient cells (pgs A‐745). Positively charged amino acids including arginine are commonly found in the CDR of the 9D7 mAb. Point mutations to the arginine residues in the CDR of the H chain of the recombinant 9D7 mAb significantly attenuated its DNA‐binding and cell‐penetration abilities. These findings indicate that cell penetration of anti‐dsDNA is due to the electrostatic interactions of arginine residues in the CDR with the negatively charged sulfated polysaccharides on the cell surface.

Galectin-1 Upregulates CXCR4 to Promote Tumor Progression and Poor Outcome in Kidney Cancer

Galectin-1, a β-galactoside-binding lectin, is involved in many physiologic and pathologic processes, including cell adhesion, differentiation, angiogenesis, and tumor progression. However, the role of galectin-1 in kidney cancer remains elusive. This study evaluated the role of galectin-1 in the progression and clinical prognosis of renal cell carcinoma. We found significant overexpression of galectin-1 in both kidney cancer cell lines and metastatic tissue specimens from patients with renal cell carcinoma. Knockdown of galectin-1 gene expression in renal cancer cell lines reduced cell invasion, clonogenic ability, and epithelial-mesenchymal transition in vitro; reduced tumor outgrowth in vivo; and inhibited the angiogenesis-inducing activity of these cells in vitro and in vivo. Galectin-1 knockdown decreased CXCR4 expression levels in kidney cancer cells, and restoration of CXCR4 expression in galectin-1-silenced cells rescued cell motility and clonogenic ability. Additional studies suggested that galectin-1 induced CXCR4 expression through activation of nuclear factor-κB (NF-κB). Analysis of patient specimens confirmed the clinical significance and positive correlation between galectin-1 and CXCR4 expression levels and revealed concomitant overexpression of galectin-1 and CXCR4 associated adversely with overall and disease-free survival. Our findings suggest that galectin-1 promotes tumor progression through upregulation of CXCR4 via NF-κB. The coordinated upregulation of galectin-1 and CXCR4 may be a novel prognostic factor for survival in patients with renal cell carcinoma and the galectin-1-CXCR4 axis may serve as a therapeutic target in this disease.

Phosphoglycerate kinase 1-overexpressing lung cancer cells reduce cyclooxygenase 2 expression and promote anti-tumor immunity in vivo

In addition to the known function in the glycolytic pathway, phosphoglycerate kinase 1 (PGK‐1) promotes reduction of plasmin disulfide bonds leading to angiostatin formation and inhibition of tumor angiogenesis. In this study, the effects of PGK‐1 on anti‐ tumor immunity against lung cancer were evaluated using the Tet‐Off control of PGK‐1 expression in the Lewis lung carcinoma (LLC‐1). There was no significant difference in cell proliferation between parental LLC‐1 and LLC‐1 transduced with PGK‐1 (PGK‐LLC‐1). However, expression of PGK‐1 was found to limit tumor growth in mice subcutaneously injected with the cell lines and tumor growth was restored after doxycycline treatment. In addition, the cell invasion ability of PGK‐LLC‐1 became weaker than that of LLC‐1. Expressions of COX‐2, TGF‐β1 and PGE2 were all found to be down‐regulated in PGK‐LLC‐1. PGK‐LLC‐1 cells treated with doxycycline recovered their COX‐2 protein expression. In the presence of conditioned medium from PGK‐LLC‐1, the endothelial cell migration was reduced. Moreover, PGK‐LLC‐1 also stimulated T lymphocytes to express higher levels of Th1 cytokine (IFN‐γ) and lower levels of IL‐10 in comparison with parental LLC‐1. PGK‐LLC‐1 cells restored the growth rate in immunodeficient mice when compared with the growth rate in normal mice. In the tissue sections, reduced COX‐2 expressions and marked infiltrated CD3 T lymphocytes were observed in the PGK‐LLC‐1 injected group. These findings indicate that overexpression of PGK‐1 in LLC‐1 reduces the COX‐2 expression, and, in turn, affect PGE2, cell invasion, angiogenesis, and the immune functions, and finally inhibit the tumor progression.