Analytical Performance Evaluation of a Digital Real-Time PCR for Quantifying Major BCR::ABL1 Transcripts.

BACKGROUND: Accurate quantification of the BCR::ABL1 transcripts is essential for measurable residual disease (MRD) monitoring in chronic myeloid leukemia (CML) after tyrosine kinase inhibitor (TKI) treatment. This study evaluated the newly developed digital real-time PCR method, Dr. PCR, as an alternative reverse transcription-PCR (qRT-PCR) for MRD detection. METHODS: The performance of Dr. PCR was assessed using reference and clinical materials. Precision, linearity, and correlation with qRT-PCR were evaluated. MRD levels detected by Dr. PCR were compared with qRT-PCR, and practical advantages were investigated. RESULTS: Dr. PCR detected MRD up to 0.0032%IS (MR4.5) with excellent precision and linearity and showed a strong correlation with qRT-PCR results. Notably, Dr. PCR identified higher levels of MRD in 12.7% (29/229) of patients than qRT-PCR, including six cases of MR4, which is a critical level for TKI discontinuation. Dr. PCR also allowed for sufficient ABL1 copies in all cases, while qRT-PCR necessitated multiple repeat tests in 3.5% (8/229) of cases. CONCLUSION: Our study provides a body of evidence supporting the clinical application of Dr. PCR as a rapid and efficient method for assessing MRD in patients with CML under the current treatment regimen.

Homogeneous One-Step Immunoassay Based on Switching Peptides for Detection of the Influenza Virus.

In this study, a homogeneous one-step immunoassay based on switching peptides is presented for the detection of influenza viruses A and B (Inf-A and Inf-B, respectively). The one-step immunoassay represents an immunoassay method that does not involve any washing steps, only treatment of the sample. In this method, fluorescence-labeled switching peptides quantitatively dissociate from the antigen-binding site of immunoglobulin G (IgG). In particular, the one-step immunoassay based on soluble detection antibodies with switching peptides is called a homogeneous one-step immunoassay. The immunoassay developed uses switching peptides labeled with two types of fluorescence dyes (FAM and TAMRA) and detection antibodies labeled with two types of fluorescence quenchers (TQ2 for FAM and TQ3 for TAMRA). The optimal switching peptides for the detection of Inf-A and Inf-B have been selected as L1-peptide and H2-peptide. The interactions between the four kinds of switching peptides and IgG have been analyzed using computational docking simulation and SPR biosensor. The location of labeling for the fluorescence quenchers has been determined based on the distance between the fluorescence dyes of the switching peptides and the fluorescence quenchers, calculated on the basis of the efficiency of fluorescence quenching, using the Förster equation. To demonstrate the feasibility of the one-step immunoassay, binding constants (KD) have been calculated for detection antibodies against Inf-A and Inf-B with target antigens (Inf-A and Inf-B) and switching peptides (L1- and H2-peptides), using an isotherm model. The immunoassay has been demonstrated to be feasible using antigens as well as real samples of Inf-A and Inf-B with a critical cycle number (Ct). The immunoassay has also been compared to other commercially available rapid test kits for Inf-A and Inf-B and found to be far more sensitive for detection of Inf-A and Inf-B over the entire detection range.

Morin inhibits PDGF-induced proliferation, migration, and invasion of vascular smooth muscle cells via modulating p27KIP1, AKT, and MMP-9 activities.

Hyper-proliferation and migration of vascular smooth muscle cells (VSMCs) are closely associated with atherosclerosis. Recently, the flavonol morin has been reported to exhibit potent anti-oxidant and anti-inflammatory activities. Therefore, we investigated molecular mechanisms of morin in VSMCs stimulated by PDGF. Morin effectively inhibited PDGF-stimulated proliferation of VSMCs through a G1 cell-cycle arrest, leading to down-regulation of CDK2, CDK4, cyclin D1, and cyclin E proteins. Interestingly, PDGF markedly down-regulated p27KIP1 protein expression; however, morin treatment restored the p27KIP1expression to the basal level. Morin did not affect phosphorylation of MAPKs (ERK, p38, and JNK); however, phosphorylation of AKT was dramatically suppressed by morin in PDGF-stimulated VSMCs. Using the PI3K inhibitor, LY294002, we revealed that AKT is a key regulator in the inhibitory mechanism of morin against PDGF-induced proliferation of VSMCs. Morin disturbed migratory and invasive potential of VSMCs via suppression of matrix metalloproteinase-9 (MMP-9) activity. Using electrophoretic mobility shift assays, we verified that NF-κB, AP-1, and Sp-1 transcription factors are implicated in the mode of action of morin, which suppresses the MMP-9 activity in PDGF-induced VSMCs. Based on the results, we believe that morin may be a potential therapeutic agent for atherosclerosis without negative side effect.

Morin Inhibits Proliferation, Migration, and Invasion of Bladder Cancer EJ Cells via Modulation of Signaling Pathways, Cell Cycle Regulators, and Transcription Factor-Mediated MMP-9 Expression.

Preclinical Research Previous studies have shown that morin exerts diverse pharmacological activities. In this study, we investigated the inhibitory activity of morin on bladder cancer EJ cells. Morin significantly inhibited EJ cell proliferation, which was related to the G1-phase cell cycle arrest together with the reduced expression of cyclin D1, cyclin E, CDK2, and CDK4 via increased expression of p21WAF1. Morin also increased ERK1/2 phosphorylation and decreased JNK and AKT phosphorylation without altering the p38MAPK phosphorylation levels. Morin treatment suppressed the migration and invasion of EJ cells in wound-healing and transwell cell invasion assays. Zymographic and electrophoretic mobility shift assays showed that morin suppressed the expression of matrix metalloproteinase-9 (MMP-9) via repression of the binding activity of AP-1, Sp-1, and NF-κB. Collectively, these results demonstrate that morin reduced cyclin D1, cyclin E, CDK2 and CDK4 expression via the induction of p21WAF1 expression, increased ERK1/2 phosphorylation and decreased JNK, and AKT phosphorylation, and prevented MMP-9 expression via the inhibition of transcription factors AP-1, Sp-1, and NF-κB, thereby resulting in the inhibition of growth, migration, and invasion of bladder cancer EJ cells. These results provide a novel insight into the use of morin in the prevention of bladder cancer. Drug Dev Res 78 : 81-90, 2017. © 2017 Wiley Periodicals, Inc.

Melanoma mouse model implicates metabotropic glutamate signaling in melanocytic neoplasia.

To gain insight into melanoma pathogenesis, we characterized an insertional mouse mutant, TG3, that is predisposed to develop multiple melanomas. Physical mapping identified multiple tandem insertions of the transgene into intron 3 of Grm1 (encoding metabotropic glutamate receptor 1) with concomitant deletion of 70 kb of intronic sequence. To assess whether this insertional mutagenesis event results in alteration of transcriptional regulation, we analyzed Grm1 and two flanking genes for aberrant expression in melanomas from TG3 mice. We observed aberrant expression of only Grm1. Although we did not detect its expression in normal mouse melanocytes, Grm1 was ectopically expressed in the melanomas from TG3 mice. To confirm the involvement of Grm1 in melanocytic neoplasia, we created an additional transgenic line with Grm1 expression driven by the dopachrome tautomerase promoter. Similar to the original TG3, the Tg(Grm1)EPv line was susceptible to melanoma. In contrast to human melanoma, these transgenic mice had a generalized hyperproliferation of melanocytes with limited transformation to fully malignant metastasis. We detected expression of GRM1 in a number of human melanoma biopsies and cell lines but not in benign nevi and melanocytes. This study provides compelling evidence for the importance of metabotropic glutamate signaling in melanocytic neoplasia.

Comparison of digital PCR platforms using the molecular marker.

Assays of clinical diagnosis and species identification using molecular markers are performed according to a quantitative method in consideration of sensitivity, cost, speed, convenience, and specificity. However, typical polymerase chain reaction (PCR) assay is difficult to quantify and have various limitations. In addition, to perform quantitative analysis with the quantitative real-time PCR (qRT-PCR) equipment, a standard curve or normalization using reference genes is essential. Within the last a decade, previous studies have reported that the digital PCR (dPCR) assay, a third-generation PCR, can be applied in various fields by overcoming the shortcomings of typical PCR and qRT-PCR assays. We selected Stilla Naica System (Stilla Technologies), Droplet Digital PCR Technology (Bio-Rad), and Lab on an Array Digital Real-Time PCR analyzer system (OPTOLANE) for comparative analysis among the various droplet digital PCR platforms currently in use commercially. Our previous study discovered a molecular marker that can distinguish Hanwoo species (Korean native cattle) using Hanwoo-specific genomic structural variation. Here, we report the pros and cons of the operation of each dPCR platform from various perspectives using this species identification marker. In conclusion, we hope that this study will help researchers to select suitable dPCR platforms according to their purpose and resources.

Electrochemical One-Step Immunoassay Based on Switching Peptides and Pyrolyzed Carbon Electrodes.

Switching peptides were designed to bind reversibly to the binding pocket of antibodies (IgG) by interacting with frame regions (FRs). These peptides can be quantitatively released when antigens bind to IgG. As FRs have conserved amino acid sequences, switching peptides can be used as antibodies for different antigens and different source animals. In this study, an electrochemical one-step immunoassay was conducted using switching peptides labeled with ferrocene for the quantitative measurement of analytes. For the effective amperometry of the switching peptides labeled with ferrocene, a pyrolyzed carbon electrode was prepared by pyrolysis of the parylene-C film. The feasibility of the pyrolyzed carbon electrode for the electrochemical one-step immunoassay was determined by analyzing its electrochemical properties, such as its low double-layer capacitance (Cdl), high electron transfer rate (kapp), and wide electrochemical window. In addition, the factors influencing the amperometry of switching peptides labeled with ferrocene were analyzed according to the hydrodynamic radius, the number of intrahydrogen bonds, dipole moments, and diffusion coefficients. Finally, the applicability of the electrochemical one-step immunoassay for the medical diagnosis of the human hepatitis B surface antigen (hHBsAg) was assessed.

One-Step Homogeneous Immunoassay for the Detection of Influenza Virus Using Switching Peptide and Graphene Quencher.

One-step homogeneous immunoassay was developed for detecting influenza viruses A and B (Inf-A and Inf-B) using the switching peptide H2. As the fluorescence-labeled switching peptide dissociated from the binding pocket of detection antibodies, the fluorescence signal could be directly generated by the binding of Inf-A and Inf-B without washing (i.e., one-step immunoassay). For the one-step homogeneous immunoassay with detection antibodies in solution, graphene was labeled with the antibodies as a fluorescence quencher. To test the feasibility of the homogeneous one-step immunoassay, the stability of the antibody complex with the switching peptide was evaluated under different pH and salt conditions. The one-step homogeneous immunoassay with switching peptide was conducted using influenza virus antigens in phosphate-buffered saline and real samples with inactivated Inf-A and Inf-B spiked in serum. Finally, the one-step homogeneous immunoassay results were compared with those of commercially available lateral flow immunoassays.

Metabotropic glutamate receptor 1 and glutamate signaling in human melanoma.

Recently, several laboratories have started to investigate the involvement of glutamate signaling in cancer. In previous studies, we reported on a transgenic mouse model that develops melanoma spontaneously. Subsequent studies in these mice identified that the aberrant expression of metabotropic glutamate receptor 1 (GRM1) in melanocytes played a critical role in the onset of melanoma. Confirmation of the etiologic role of GRM1 in melanoma development was shown in a second transgenic line with GRM1 expression under the regulation of a melanocyte-specific dopachrome tautomerase promoter. Ectopic expression of GRM1 was also detected in a subset of human melanoma cell lines and biopsies, suggesting that aberrant expression of GRM1 in melanocytes may contribute to the development of human melanoma. GRM1, a seven-transmembrane domain G protein-coupled receptor, is normally expressed and functional in neuronal cells, and its ligand, glutamate, is the major excitatory neurotransmitter. Human melanoma cells are shown here to release elevated levels of glutamate, implying a possible autocrine loop. Treatment of GRM1-expressing human melanoma cells with a GRM1 antagonist (LY367385 or BAY36-7620) or a glutamate release inhibitor (riluzole) leads to a suppression of cell proliferation as well as a decrease in levels of extracellular glutamate. Treatment of human melanoma cell xenografts with riluzole for 18 days via p.o. gavage or i.v. injection leads to inhibition of tumor growth by 50% in comparison with controls. These data suggest the importance of glutamate signaling in human melanoma and imply that the suppression of glutamate signaling may be a new target for melanoma therapy.

Carnosine exerts antitumor activity against bladder cancers in vitro and in vivo via suppression of angiogenesis.

Carnosine, a naturally occurring dipeptide, was recently reported to exhibit anticancer activity; however, the molecular mechanisms and regulators underlying its activity against tumor-associated angiogenesis remain unidentified. In this study, we evaluated the in vitro and in vivo antitumor effects of carnosine in EJ bladder cancer cells and EJ-xenografted BALB/c nude mice, respectively. In addition, in vitro capillary tube formation of HUVECs, ex vivo aortic ring and in vivo Matrigel plug assays were employed to examine the antiangiogenic potential of carnosine. Carnosine significantly inhibited EJ cell proliferation. Flow cytometric and immunoblot analyses indicated that carnosine modulated regulators of the G1 cell cycle phase, including cyclin D1, CDK4 and p21WAF1. The mitogen-activated protein kinases, ERK and p38, but not JNK or AKT, responded to carnosine. Carnosine inhibited the migratory and invasive potential of EJ cells by inhibiting MMP-9 activity, which was associated with suppression of binding activity of NF-κB, SP-1 and AP-1. In xenograft tumors, carnosine exhibited antitumor activity equivalent to cisplatin, but no weight loss occurred in carnosine-treated mice. In HUVECs, carnosine inhibited VEGF-mediated proliferation, colony tube formation, migration and invasion. The antiangiogenic activity of carnosine was partially due to the suppression of VEGFR-2-mediated ERK/AKT/eNOS signaling and MMP-2. Furthermore, using aortic ring and Matrigel plug assays, we confirmed the antiangiogenic activity of carnosine. Given that targeting tumor-associated angiogenesis is a proven effective therapeutic strategy, our results may provide valuable information for the development of preventive or therapeutic agents for bladder cancer patients.

Nimbolide Represses the Proliferation, Migration, and Invasion of Bladder Carcinoma Cells via Chk2-Mediated G2/M Phase Cell Cycle Arrest, Altered Signaling Pathways, and Reduced Transcription Factors-Associated MMP-9 Expression.

Nimbolide, an active chemical constituent of Azadirachta indica, reportedly has several physiological effects. Here, we assessed novel anticancer effects of nimbolide against bladder cancer EJ and 5637 cells. Nimbolide treatment inhibited the proliferation of both bladder cancer cell lines with an IC50 value of 3 µM. Treatment of cells with nimbolide induced G2/M phase cell cycle arrest via both Chk2-Cdc25C-Cdc2/cyclin B1-Wee1 pathway and Chk2-p21WAF1-Cdc2/cyclin B1-Wee1 pathway. Nimbolide increased JNK phosphorylation and decreased p38MAPK and AKT phosphorylation. Additionally, nimbolide impeded both wound healing migration and invasion abilities by suppressing matrix metalloproteinase-9 (MMP-9) activity. Finally, nimbolide repressed the binding activity of NF-κB, Sp-1, and AP-1 motifs, which are key transcription factors for MMP-9 activity regulation. Overall, our study indicates that nimbolide is a potential chemotherapeutic agent for bladder cancer.

Hydrangenol suppresses VEGF-stimulated angiogenesis by targeting p27KIP1-dependent G1-cell cycle arrest, VEGFR-2-mediated signaling, and MMP-2 expression.

We previously reported that hydrangenol has potent antitumor activity against human bladder cancer EJ cells. Here, we investigated the antiangiogenic activity of hydrangenol using in vitro and ex vivo models. Treatment with hydrangenol significantly inhibited the proliferation of vascular endothelial growth factor (VEGF)-induced HUVECs in a concentration-dependent manner (EC50 = 10 µM). Flow cytometry analysis revealed that hydrangenol suppressed the VEGF-induced inhibition of G1-cell cycle phase and also decreased cyclin D1, cyclin E, CDK2, and CDK4 levels. Hydrangenol-mediated arrest in the G1-cell cycle phase was associated with p27KIP1 level, but not p21WAF1 or p53 level. Hydrangenol also significantly inhibited VEGFR-2-mediated signaling pathways including ERK1/2, AKT, and endothelial nitric oxide synthase. Interestingly, immunoprecipitation assay demonstrated that the inhibition of VEGFR-2 activation was independent of VEGF binding, thereby suggesting an allosteric regulation of hydrangenol against VEGFR-2. Additionally, hydrangenol inhibited migration, invasion, and capillary-like tubular formation in VEGF-stimulated HUVECs. Zymography and immunoblot analyses revealed that these inhibitory activities were partially owing to the VEGF-induced inhibition of matrix metalloproteinase-2 activity. Finally, VEGF-mediated microvessel sprouting was inhibited in the presence of hydrangenol in ex vivo aortic ring assay. Taken together, hydrangenol possesses a potent antiangiogenesis potential; thus we believe that hydrangenol may be developed as a therapeutic reagent to treat angiogenesis-mediated diseases.

Triacanthine exerts antitumor effects on bladder cancer in vitro and in vivo.

BACKGROUND: Numerous studies have focused on solvent extracts from locust trees (Gleditsia spp.), which contain diverse bioactive components including saponins, flavonoids, and alkaloids. However, because of the undefined nature of such phytochemicals, their clinical application as chemotherapeutic agents has often been limited. PURPOSE: This study aimed to evaluate the anti-oncogenic activity of triacanthine, an alkaloid obtained from Gleditsia triacanthos L. STUDY DESIGN: The anti-oncogenicity of triacanthine in vitro was evaluated via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, cell-counting kit-8 assay (CCK-8 assay), flow cytometry, imunoblot, migration and invasion assays, zymography, and electrophoretic mobility shift assay in the human bladder carcinoma cell line EJ. The in vivo efficacy of triacanthine was evaluated via oral administration to EJ-xenografted BALB/c nude mice. To identify the side effects of triacanthine, cisplatin was also administered and an acute toxicity test was performed. RESULTS: Triacanthine significantly inhibited EJ cell proliferation (IC50 600 µM). Flow cytometry analysis revealed that cells were arrested in the G1 phase, and apoptotic cells accumulated in sub-G1 phase in a dose-dependent manner. Triacanthine inhibited the G1-S transition by deterring complex formation between cyclin-dependent kinases and cyclins, thereby up-regulating cell cycle inhibitors p21WAF1 and p27KIP1. In addition, triacanthine induced a caspase-dependent extrinsic pathway of apoptosis and autophagy. Early responsive kinases, extracellular signal-regulated kinase (ERK) and Janus kinase (JNK) were up-regulated by triacanthine. Triacanthine-mediated inhibition of the migratory and invasive potential of EJ cells was attributed to reduction of matrix metalloproteinase (MMP)-9 due to suppression of binding activities of the transcription factors activator protein (AP)-1, specificity protein (Sp)-1, and nuclear factor (NF)-κB. In an in vivo study, triacanthine significantly limited growth of xenografted tumors. Interestingly, while cisplatin resulted in significant weight loss after a 5-mg/kg dose, triacanthine did not cause weight loss, behavioral abnormalities, altered biochemical parameters, or tissue staining. A single oral dose acute-toxicity test (triacanthine 2,000 mg/kg) produced no adverse cytotoxic effects via blood biochemical tests and tissue-organ staining. CONCLUSION: To our knowledge, this is the first systematic evaluation of the anti-oncogenic activity of triacanthine. Therefore, we believe that our findings may guide the development of novel chemotherapeutic agents for bladder cancers.

Metabotropic glutamate receptors (mGlus) and cellular transformation.

Although the glutamatergic system usually functions in the CNS, expression has been observed in non-neuronal tissues and a subset of cancers. Metabotropic glutamate receptors (mGlus) are highly "druggable" GPCRs and thus a priority for validation as therapeutic targets. We have previously reported that the aberrant expression of mGlu1 is sufficient to induce spontaneous melanoma development in vivo. We isolated and characterized several stable mGlu1-mouse melanocytic clones and demonstrated that these clones are transformed and tumorigenic. We hypothesize that expression of mGlus may not be uncommon in the pathogenesis of tumors other than melanoma, and that activity of an otherwise normal glutamate receptor in an ectopic cellular environment involves signaling pathways which dysregulate cell growth, ultimately leading to tumorigenesis. As most human cancers are of epithelial origin (carcinomas), in this review, the possibility that mGlu1 could function as a complete oncogene and transform epithelial cells is also discussed.

Participation of xCT in melanoma cell proliferation in vitro and tumorigenesis in vivo.

Our research group demonstrated that riluzole, an inhibitor of glutamatergic signaling reduced melanoma cell proliferation in vitro and tumor progression in vivo. The underlying mechanisms of riluzole are largely unknown. Microarray analyses on two human melanoma cell lines revealed that riluzole stimulates expression of the cystine-glutamate amino acid antiporter, xCT (SLC7A11). Western immunoblot analysis from cultured human melanoma or normal melanocytic cells showed that xCT was significantly overexpressed in most melanomas, but not normal cells. Studies using human tumor biopsy samples demonstrated that overexpression of xCT was correlated with cancer stage and progression. To further investigate if xCT is involved in melanoma cell growth, we derived several stable clones through transfection of exogenous xCT to melanoma cells that originally showed very low expression of xCT. The elevated xCT expression promoted cell proliferation in vitro and inversely, these melanoma clones showed a dose-dependent decrease in cell proliferation in response to riluzole treatment. Xenograft studies showed that these clones formed very aggressive tumors at a higher rate compared to vector controls. Conversely, treatment of xenograft-bearing animals with riluzole down-regulated xCT expression suggesting that xCT is a molecular target of riluzole. Furthermore, protein lysates from tumor biopsies of patients that participated in a riluzole monotherapy phase II clinical trial showed a reduction in xCT levels in post-treatment specimens from patients with stable disease. Taken together, our results show that xCT may be utilized as a marker to monitor patients undergoing riluzole-based chemotherapies.

Inhibitory effect of Au@Pt-NSs on proliferation, migration, and invasion of EJ bladder carcinoma cells: involvement of cell cycle regulators, signaling pathways, and transcription factor-mediated MMP-9 expression.

BACKGROUND: Although the diverse biological properties of nanoparticles have been studied intensively, research into their mechanism of action is relatively rare. In this study, we investigated the molecular mechanisms of the anticancer activity of heterometallic Au@Pt-nanoseeds (NSs) against bladder cancers. MATERIALS AND METHODS: Mode of action of Au@Pt-NSs was investigated through MTT assay, flow cytometry analysis, Western immunoblots, real-time qPCR, wound-healing migration and invasion assays, zymography, and electrophoretic mobility shift assay (EMSA). RESULTS: Treatment with Au@Pt-NSs significantly inhibited the proliferation of EJ cells in a dose-dependent manner by inducing G1 phase cell cycle arrest. Among the regulators associated with the G1 cell cycle phase, CDK2, CDK4, cyclin D1, cyclin E, and p21WAF1 were shown to participate in the inhibitory pathways of Au@Pt-NSs. In addition, treatment with Au@Pt-NSs led to upregulation of phospho-p38 MAPK and downregulation of phospho-AKT in EJ cells. Interestingly, Au@Pt-NSs inhibited the migratory and invasive potential of the cells, which was attributed to the suppression of the enzymatic activity of matrix metalloproteinase-9 (MMP-9). Using MMP-9-specific oligonucleotides, we showed that transcription factors such as NF-κB and Sp-1 were responsible for the MMP-9-mediated metastatic potential of EJ cells. CONCLUSION: Au@Pt-NSs significantly limited the progression, migration, and invasion of bladder cancer EJ cells. Our data represent a novel insight into developing cisplatin-like chemotherapeutic reagents with fewer side effects and provide useful information on molecular markers to monitor patients under Au@Pt-NSs-based chemotherapy.

Hydrangenol inhibits the proliferation, migration, and invasion of EJ bladder cancer cells via p21WAF1-mediated G1-phase cell cycle arrest, p38 MAPK activation, and reduction in Sp-1-induced MMP-9 expression.

Hydrangenol is a dihydroisocoumarin that is mainly obtained from Hydrangea macrophylla. Recently, hydrangenol has garnered attention since several studies have reported that it has anti-inflammatory, anti-allergic, anti-diabetic, and anti-malarial activities. However, there have been few studies on the effect of hydrangenol on oncogenesis. In this study, we evaluated the anti-cancer activity of hydrangenol against the EJ bladder cancer cell line. Hydrangenol significantly inhibited the proliferation of EJ cells in a dose-dependent manner with an IC50 of 100 µM. Flow cytometry and immunoblotting experiments indicated that EJ cells were arrested in the G1-phase of the cell cycle and showed reduced expression of CDK2, CDK4, cyclin D1, and cyclin E mediated via the upregulation of p21WAF1. Hydrangenol increased the phosphorylation of p38 MAPK without affecting the phosphorylation of ERK and JNK. In addition, hydrangenol significantly inhibited the migratory and invasive activities of EJ cells by suppressing the enzymatic activity of MMP-9. Electrophoretic mobility shift assays suggested that the inhibition of MMP-9 activity by hydrangenol was attributable to its suppression of the Sp-1 transcription factor binding activity. This study is the first report on the mode of action of hydrangenol as an inhibitor of bladder cancer. We believe that these results provide novel insights that could aid the development of hydrangenol-based chemotherapeutic agents.

Stimulation of oncogenic metabotropic glutamate receptor 1 in melanoma cells activates ERK1/2 via PKCepsilon.

Metabotropic glutamate receptor 1 (Grm1, formerly mGluR1) is a G protein coupled receptor (GPCR) normally expressed and functional in the central nervous system. Studies of our transgenic mouse melanoma model (TG-3) revealed that ectopic expression of Grm1 in melanocytes is sufficient to induce melanoma development in vivo [P.M. Pollock, K. Cohen-Solal, R. Sood, J. Namkoong, J.J. Martino, A. Koganti, H. Zhu, C. Robbins, I. Makalowska, S.S. Shin, Y. Marin, K.G. Roberts, L.M. Yudt, A. Chen, J. Cheng, A. Incao, H.W. Pinkett, C.L. Graham, K. Dunn, S.M. Crespo-Carbone, K.R. Mackason, K.B. Ryan, D. Sinsimer, J. Goydos, K.R. Reuhl, M. Eckhaus, P.S. Meltzer, W.J. Pavan, J.M. Trent, S. Chen, Nat. Genet. 34 (2003) 108-112.]. We have established and characterized several cell lines in vitro from independent mouse melanoma tumors [Y.E. Marín, J. Namkoong, S.S. Shin, J. Raines, K. Degenhardt, E. White, S. Chen, Neuropharmacol. 49 (2005) 70-79.]. These cell lines are useful tools in the studies of signaling events that may be mediated by Grm1 in transformed melanocytes. Here we show that stimulation of Grm1 by l-quisqualate, a group I metabotropic glutamate receptor agonist, results in inositol triphosphate (IP3) accumulation, and the activation of ERK1/2 in these cell lines. IP3 accumulation and ERK1/2 activation were inhibited by pretreatment of the tumor cells with a Grm1-specific antagonist (LY367385) or by dominant negative mutants of Grm1, demonstrating the specificity of these events. We also show that ERK1/2 activation by Grm1 was PKC-dependent, but cAMP and PKA-independent. PKCepsilon was shown to play a pivotal role in Grm1-mediated ERK1/2 phosphorylation. Insights into the signaling cascades mediated by Grm1 in melanoma cells may aid in the identification of key molecular targets for the future design of combined therapies for melanoma.

HSPA6 augments garlic extract-induced inhibition of proliferation, migration, and invasion of bladder cancer EJ cells; Implication for cell cycle dysregulation, signaling pathway alteration, and transcription factor-associated MMP-9 regulation.

Although recent studies have demonstrated the anti-tumor effects of garlic extract (GE), the exact molecular mechanism is still unclear. In this study, we investigated the molecular mechanism associated with the inhibitory action of GE against bladder cancer EJ cell responses. Treatment with GE significantly inhibited proliferation of EJ cells dose-dependently through G2/M-phase cell cycle arrest. This G2/M-phase cell cycle arrest by GE was due to the activation of ATM and CHK2, which appears to inhibit phosphorylation of Cdc25C (Ser216) and Cdc2 (Thr14/Tyr15), this in turn was accompanied by down-regulation of cyclin B1 and up-regulation of p21WAF1. Furthermore, GE treatment was also found to induce phosphorylation of MAPK (ERK1/2, p38MAPK, and JNK) and AKT. In addition, GE impeded the migration and invasion of EJ cells via inhibition of MMP-9 expression followed by decreased binding activities of AP-1, Sp-1, and NF-κB motifs. Based on microarray datasets, we selected Heat shock protein A6 (HSPA6) as the most up-regulated gene responsible for the inhibitory effects of GE. Interestingly, overexpression of HSPA6 gene resulted in an augmentation effect with GE inhibiting proliferation, migration, and invasion of EJ cells. The augmentation effect of HSPA6 was verified by enhancing the induction of G2/M-phase-mediated ATM-CHK2-Cdc25C-p21WAF1-Cdc2 cascade, phosphorylation of MAPK and AKT signaling, and suppression of transcription factor-associated MMP-9 regulation in response to GE in EJ cells. Overall, our novel results indicate that HSPA6 reinforces the GE-mediated inhibitory effects of proliferation, migration, and invasion of EJ cells and may provide a new approach for therapeutic treatment of malignancies.

Angiopoietin-like protein 4 potentiates DATS-induced inhibition of proliferation, migration, and invasion of bladder cancer EJ cells; involvement of G2/M-phase cell cycle arrest, signaling pathways, and transcription factors-mediated MMP-9 expression.

Background: Diallyl trisulfide (DATS), a bioactive sulfur compound in garlic, has been highlighted due to its strong anti-carcinogenic activity. Objective: The current study investigated the molecular mechanism of garlic-derived DATS in cancer cells. Additionally, we explored possible molecular markers to monitoring clinical responses to DATS-based chemotherapy. Design: EJ bladder carcinoma cells were treated with different concentration of DATS. Molecular changes including differentially expressed genes in EJ cells were examined using immunoblot, FACS cell cycle analysis, migration and invasion assays, electrophoresis mobility shift assay (EMSA), microarray, and bioinformatics analysis. Results: DATS inhibited EJ cell growth via G2/M-phase cell cycle arrest. ATM-CHK2-Cdc25c-p21WAF1-Cdc2 signaling cascade, MAPKs, and AKT were associated with the DATS-mediated growth inhibition of EJ cells. DATS-induced inhibition of migration and invasion was correlated with down-regulated MMP-9 via reduced activation of AP-1, Sp-1, and NF-κB. Through microarray gene expression analysis, ANGPTL4, PLCXD1, and MMP3 were identified as candidates of molecular targets of DATS. Introduction of each gene to EJ cells revealed that ANGPTL4 was associated with the DATS-induced inhibition of cell growth, migration, and invasion. Conclusions: ANGPTL4 regulates DATS-mediated inhibition of proliferation, migration, and invasion of EJ cells, and thus, has potential as a prognostic marker for bladder cancer patients.