u-0126 and Urinary-Bladder-Neoplasms

Multidrug resistance is a major treatment obstacle for recurrent and metastatic bladder cancer, which often leads to disease progression and poor clinical outcome. Although overexpression of interleukin-6 (IL-6) appears to play a critical role in the development of chemotherapy resistance, inhibitors for IL-6 alone have not improved clinical outcomes. Since the IL-6/IL-6R/GP130 complex is involved in multidrug resistance, another strategy would be to focus on glycoprotein-130 (GP130) since it dimerizes with IL-6R/CD26 as a membrane-bound signaling transducer receptor and initiates subsequent signaling activation and may be a potential therapeutic target. Currently, the role of GP130 in chemoresistant bladder cancer is unknown. In the present study, we demonstrate that GP130 is over-expressed in cisplatin and gemcitabine-resistant bladder cancer cells, and that the inhibition of GP130 expression significantly reduces cell viability, survival and migration. Downstream of GP130 is PI3K/AKT/mTOR signaling, which is inactivated by SC144, a GP130 inhibitor. However, Raf/MEK/ERK signaling, which also is downstream of GP130 is activated by SC144. This activation is likely based on a mTOR/S6K1/PI3K/ERK negative feedback loop, which is presumed to counteract the inhibitory effect of SC144 on tumor aggressiveness. Blocking both GP130 and pERK resulted in synergistic inhibition of cytotoxicity, clonal survival rates and cell migration in our chemotherapy resistant bladder cancer cells. This vertical inhibition offers a novel therapeutic strategy for targeting human chemoresistant bladder cancer.

Topics: Butadienes; Carcinoma, Transitional Cell; Cell Line, Tumor; Cell Movement; Cell Survival; Drug Resistance, Neoplasm; Drug Synergism; Enzyme Inhibitors; Gene Expression Regulation, Neoplastic; Glycoproteins; Humans; Hydrazines; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase 1; Nitriles; Quinoxalines; Urinary Bladder Neoplasms

Resistance of bladder cancer to cisplatin is a major obstacle to successful treatment. In the current study, we investigated the apoptotic effects of curcumin and cisplatin co-treatment in 253J-Bv(p53 wild-type) and T24(p53 mutant) bladder cancer. We found that curcumin and cisplatin co-treatment primarily targets reactive oxygen species(ROS) and extracellular regulated kinase(ERK) signaling during the apoptosis induction in bladder cancer. The apoptosis rate in 253J-Bv and T24 cells co-treated with curcumin and cisplatin was increased compared to that in cells exposed to single-agent treatment conditions. Also, caspase-3 activation and ROS production were observed in both cells treated with curcumin and cisplatin, together with upregulation of p-MEK and p-ERK1/2 signaling. NAC(ROS scavenger) and U0126(ERK inhibitor) inhibited apoptosis induced by curcumin and cisplatin. In addition, when 253J-Bv cells were co-treated with curcumin and cisplatin, p53 and p21 expression levels were markedly increased when compared to controls. Unlike 253J-Bv cells, T24 cells were co-treated with curcumin and cisplatin revealed an induction of apoptosis through decreased p-signal transducer and activator of transcription 3(STAT3) expression. Moreover, pretreatment with U0126 suppressed curcumin and cisplatin-induced upregulation of p53, p21, and p-STAT3 and downregulation of survival proteins in both cells. In conclusion, co-treatment with curcumin and cisplatin synergistically induced apoptosis through ROS-mediated activation of ERK1/2 in bladder cancer.

Topics: Animals; Antineoplastic Agents; Apoptosis; Butadienes; Caspase 3; Cell Line, Tumor; Cisplatin; Curcumin; Drug Synergism; Enzyme Activation; Enzyme Inhibitors; Extracellular Signal-Regulated MAP Kinases; Female; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Nitriles; Oxidative Stress; Reactive Oxygen Species; Signal Transduction; Tumor Suppressor Protein p53; Up-Regulation; Urinary Bladder Neoplasms

Interleukin-15 (IL-15) functions as a key regulator for the proliferation, differentiation, and activation of lymphocytes. However, the role of IL-15 in cancer biology is not yet understood. In the present study, IL-15 treatment stimulated the wound-healing migration and invasion of bladder cancer 5637 cells, without altering the proliferation of the cells. Treatment of 5637 cells with IL-15 resulted in the promotion of the MMP-9 expression and the activation of NF-κB binding, which is a functional transcription factor that activates MMP-9 expression. In addition, IL-15 induced the activation of ERK1/2. ERK inhibitor U0126 suppressed the migration, invasion, MMP-9 expression, and NF-κB binding activity in IL-15-treated 5637 cells. In addition, the cell-cycle inhibitor p21WAF1 was induced by the addition of IL-15. Finally, the siRNA-mediated knockdown of p21WAF1 attenuated the IL-15-induced stimulation of migration, invasion, ERK1/2 activation, MMP-9 expression, and NF-κB binding activation in 5637 cells. Our results suggest that p21WAF1 regulated NF-κB-mediated MMP-9 expression via the activation of ERK1/2, which resulted in the migration and invasion of 5637 cells treated with IL-15. These unexpected results suggest a potential role for IL-15 with respect to the progression of bladder cancer.

Topics: Butadienes; Cell Line, Tumor; Cell Movement; Extracellular Signal-Regulated MAP Kinases; Gene Expression Regulation, Neoplastic; Humans; Interleukin-15; Matrix Metalloproteinase 9; Neoplasm Invasiveness; NF-kappa B; Nitriles; RNA, Small Interfering; Signal Transduction; Tumor Suppressor Protein p53; Up-Regulation; Urinary Bladder Neoplasms

Erythropoietin (EPO) is a cytokine that modulates the production of red blood cells. Previous studies have contradicted the assumed role of EPO in tumor cell proliferation. In the present study, we investigated the effect of EPO in the proliferation, migration and invasion that is involved in the signaling pathways and cell-cycle regulation of bladder cancer 5637 cells. The results showed that an overexpression of the EPO gene has a potent stimulatory effect on DNA synthesis, migration and invasion. EPO gene expression increased the expression of matrix metalloproteinase (MMP)-9 via the binding activity of NF-κB, AP-1 and Sp-1 in 5637 cells. The transfection of 5637 cells with the EPO gene induced the phosphorylation of ERK1/2. Treatment with ERK1/2 inhibitor U0126 significantly inhibited the increased proliferation, migration and invasion of EPO gene-transfected cells. U0126 treatment suppressed the induction of MMP-9 expression through NF-κB binding activity in EPO gene transfectants. In addition, EPO gene expression was correlated with the upregulation of cyclins/CDKs and the upregulation of the CDK inhibitor p21WAF1 expression. Finally, the inhibition of p21WAF1 function by siRNA blocked the proliferation, migration, invasion and phosphorylation of ERK1/2 signaling, as well as MMP-9 expression and activation of NF-κB in EPO gene-transfected cells. These novel findings suggest that the molecular mechanisms of EPO contribute to the progression and development of bladder tumors.

Topics: Butadienes; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p21; Erythropoietin; Gene Expression Regulation, Neoplastic; Humans; MAP Kinase Signaling System; Neoplasm Invasiveness; Nitriles; Phosphorylation; Urinary Bladder Neoplasms

Bladder cancer is one of the most common tumors of the genitourinary tract; however, the molecular events underlying growth and invasion of the tumor remain unclear. Here, role of the CXCR7 receptor in bladder cancer was further explored. CXCR7 protein expression was examined using high-density tissue microarrays. Expression of CXCR7 showed strong epithelial staining that correlated with bladder cancer progression. In vitro and in vivo studies in bladder cancer cell lines suggested that alterations in CXCR7 expression were associated with the activities of proliferation, apoptosis, migration, invasion, angiogenesis and tumor growth. Moreover, CXCR7 expression was able to regulate expression of the proangiogenic factors IL-8 or VEGF, which may involve in the regulation of tumor angiogenesis. Finally, we found that signaling by the CXCR7 in bladder cancer cells activates AKT, ERK and STAT3 pathways. The AKT and ERK pathways may reciprocally regulate, which are responsible for in vitro and in vivo epithelial to mesenchymal transition (EMT) process of bladder cancer. Simultaneously targeting the two pathways by using U0126 and LY294002 inhibitors or using CCX733, a selective CXCR7 antagonist drastically reduced CXCR7-induced EMT process. Taken together, our data show for the first time that CXCR7 plays a role in the development of bladder cancer. Targeting CXCR7 or its downstream-activated AKT and ERK pathways may prove beneficial to prevent metastasis and provide a more effective therapeutic strategy for bladder cancer.

Topics: Animals; Butadienes; Chromones; Disease Progression; Epithelial-Mesenchymal Transition; Gene Expression Regulation, Neoplastic; Humans; Interleukin-8; MAP Kinase Signaling System; Mice; Mice, SCID; Morpholines; Neovascularization, Pathologic; Nitriles; Proto-Oncogene Proteins c-akt; Receptors, CXCR; RNA, Small Interfering; Signal Transduction; STAT3 Transcription Factor; Urinary Bladder Neoplasms; Vascular Endothelial Growth Factor A

Since bacterial invasion into host cells is an important step in the infection process, using the agents to interfere with bacterial internalization is an attractive approach to block the infection process. In this work, we describe a new, previously unrecognized role of the human cationic host defense peptide HMGN2 during Klebsiella pneumoniae infections. Our results revealed that the internalization of K. pneumoniae strain 03183 into cultured bladder epithelial cells (T24) was significantly reduced at HMGN2 concentrations that were unable to produce any bacteriostatic or bactericidal effect. Using microarrays and follow-up studies, we demonstrated that HMGN2 affected the internalization of K. pneumoniae strain 03183 by inhibiting the attachment of bacteria, and then decreasing bacteria-induced ERK1/2 activation and actin polymerization, which might contribute to bacterial internalization into T24 cells. This disruption of bacterial internalization implied that HMGN2 could provide protection against K. pneumoniae infections.

Topics: Actins; Anti-Bacterial Agents; Bacterial Adhesion; Blotting, Western; Butadienes; Cell Line, Tumor; Endocytosis; Enzyme Activation; Epithelial Cells; Flavonoids; Gene Expression Profiling; Gene Expression Regulation, Bacterial; HMGN2 Protein; Host-Pathogen Interactions; Humans; Klebsiella pneumoniae; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Nitriles; Oligonucleotide Array Sequence Analysis; Recombinant Proteins; Time Factors; Urinary Bladder Neoplasms

The expression of matrix metalloproteinase-9 (MMP-9) has been implicated in tumor invasion and metastasis. In this study, the factors and signaling pathways that are involved in the regulation of the MMP-9 expression were examined in urinary bladder cancer HT1376 cells. Tumor necrosis factor-alpha (TNF-alpha) stimulated the secretion of MMP-9 in HT1376 cells, as shown by zymography and immunoblot analysis. At the level of transcription, TNF-alpha also stimulated 5'-flanking promoter activity of MMP-9. Transcription factor NF-kappaB, AP-1 and Sp-1 binding sites were identified by a gel shift assay to be cis-elements for TNF-alpha activation of the MMP-9 promoter. TNF-alpha activates multiple signaling pathways in HT1376 cells, including the extracellular signal-regulated kinase (ERK1/2), p38 MAP kinase and JNK pathways. Chemical inhibitors, which specifically inhibit each of these TNF-alpha-activated pathways, were used to examine the signaling pathways involved in TNF-alpha-mediated MMP-9 expression. The ERK1/2 inhibitor, U0126 and the p38 MAP kinase inhibitor, SB203580, significantly down-regulated TNF-alpha-induced MMP-9 expression and promoter activity. The transactivation of TNF-alpha-stimulated NF-kappaB, AP-1 and Sp-1 were inhibited by U0126 and SB203580 treatment. In conclusion, the findings of the present study indicate that TNF-alpha induces MMP-9 expression in HT1376 cells by activating transcription factors, which are involved in the ERK1/2- and p38 MAP kinase-mediated control of MMP-9 regulation, namely, NF-kappaB, AP-1 and Sp-1.

Topics: Butadienes; Cell Line, Tumor; DNA; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Humans; Imidazoles; JNK Mitogen-Activated Protein Kinases; MAP Kinase Signaling System; Matrix Metalloproteinase 9; Nitriles; p38 Mitogen-Activated Protein Kinases; Promoter Regions, Genetic; Pyridines; Tumor Necrosis Factor-alpha; Urinary Bladder Neoplasms