Upregulation of TRAG3 gene in urothelial carcinoma of the bladder

Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9110, USA.
International Journal of Cancer (Impact Factor: 5.09). 06/2011; 128(12):2823-32. DOI: 10.1002/ijc.25631
Source: PubMed


Conventional chemotherapy is commonly used for advanced stages of bladder cancer with modest success and high morbidity. Identifying markers of resistance will allow clinicians to tailor treatment to a specific patient population. T24-tumorigenic cell line was grown orthotopically in nude mice and monitored using bioluminescence imaging and microcomputed tomography until they developed metastases. Stable sublines were then developed from primary bladder (T24-P), lung (T24-L) and bone (T24-B) tissues. Chromosomal analysis and DNA microarray were used to characterize these sublines. Real-time quantitative polymerase chain reaction and immunohistochemistry were used for validation. Epigenetic modifiers were used to study gene regulation. The cell viability was quantified with MTT assay. Chromosomal analysis revealed multiple alterations in metastatic cell lines compared to T24-P. DNA microarray analysis showed that taxol resistance-associated gene (TRAG) 3 was the most upregulated gene. From real-time quantitative polymerase chain reaction and immunohistochemistry, TRAG3 was significantly higher in T24-L and T24-B than T24-P. TRAG3 gene expression is likely controlled by DNA methylation but not histone acetylation. Interestingly, T24-B and T24-L cells were more resistant than T24-P to treatment with antimicrotubule agents such as docetaxel, paclitaxel and vinblastine. TRAG3 mRNA expression was higher in 20% of patients with ≤ pT2 (n = 10) and 60% of patients with ≥ pT3 (n = 20) compared to normal adjacent tissue (p = 0.05). In addition, the median TRAG3 expression was 6.7-fold higher in ≥ pT3 tumors compared to ≤ pT2 tumors. Knowing the status of TRAG3 expression could help clinicians tailor treatment to a particular patient population that could benefit from treatment, while allocating patients with resistant tumors to new experimental therapies.

Download full-text


Available from: Eugene Frenkel, Mar 25, 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: Although metastatic disease is lethal in the majority of bladder cancer cases, study on the molecular mechanism(s) of this process suffers from the limited source of distant metastatic tumor tissues and very few suitable animal models. To address this need, we generated an orthotopic animal model by instilling human bladder cancer T24-tumorigenic (T24-t) cells into mouse bladder, and sublines were subsequently derived as primary (T24-parental, T24-P) and lung metastatic (T24-L) sites. Data from invasion, migration, and adhesion assays suggested higher metastatic potential of T24-L cells than T24-P cells in vitro. Using two metastatic models to assess the metastatic ability in vivo, T24-L cells exhibited higher incidence of tumor metastasis. Mechanistically, the up-regulation of MMP-1 and HIF-1α was observed in T24-L cells. Knocking down HIF-1α can significantly down-regulate the expression of MMP-1, accompanied by the decreased invasion ability in vitro. Using immunohistochemical staining, we further observed HIF-1α elevation in the metastatic lymphomatic tissues compared with the primary bladder cancer tissues from the same patients. Taken together, our study provides the evident of the function of HIF-1α/MMP-1 in regulating metastasis of bladder cancer and HIF-1α as a potential target for controlling bladder cancer metastasis.
    No preview · Article · Feb 2012 · Urologic Oncology
  • [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVES: The Snail family of zinc finger transcription factors (i.e., Snail and Slug) predicts the tumor recurrence in superficial bladder cancers, while their roles in the development of muscle-invasion, metastasis, and chemoresistance in muscle-invasive bladder cancers with poor prognosis have not been investigated. This study evaluates the clinical significance of Slug in aggressive bladder cancer. MATERIALS AND METHODS: A pair of sublines (i.e., T24-P and T24-L) from a unique orthotropic metastatic model of bladder cancer was firstly utilized to identify the potential precursors contributing to those aggressive phenotypes. The coexpression of Slug, E-cadherin, and N-cadherin in bladder cancer cell lines (i.e., 5637, RT4, 253 J, J82, and T24) and tissues was evaluated by reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemistry staining analysis. The function of Slug expression on E- to N-cadherin switch, cell invasion, and chemoresistance to proapoptotic treatment was validated by gain-in-function and knockdown strategy in vitro. RESULTS: Slug was identified as one of the novel targets contributed to the aggressive phenotypes of T24-L cells, which showed enhanced cell invasive, metastatic, and chemoresistant potentials in vitro and in vivo as previously described. Up-regulation of Slug was significantly correlated with a higher tumor stage and the E- to N-cadherin switch in bladder cancer cells and tissues, whereas ectopic expression of Slug in bladder cancer 5637 and RT-4 cell lines promoted epithelial-to-mesenchymal transition (EMT), increased cell invasiveness and chemoresistance. By contrast, knocking down Slug using siRNA in T24-L cell lines reversed these changes. CONCLUSIONS: Slug elevates in invasive or metastatic bladder cancer and plays a critical role in EMT via control of cadherin switch. Slug may be a potential marker or target for improving the diagnosis and treatment of muscle-invasive bladder cancers.
    No preview · Article · Mar 2012 · Urologic Oncology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Practical methods for enhancing protein production in vivo remain a challenge. RNA activation (RNAa) is emerging as one potential solution by using double-stranded RNA (dsRNA) to increase endogenous gene expression. This approach, although related to RNA interference (RNAi), facilitates a response opposite to gene silencing. Duplex dsP21-322 and its chemically modified variants are examples of RNAa-based drugs that inhibit cancer cell growth by inducing expression of tumor suppressor p21(WAF1/CIP1) (p21). In this study, we investigate the therapeutic potential of dsP21-322 in an orthotopic model of bladder cancer by formulating a 2'-fluoro-modified derivative (dsP21-322-2'F) into lipid nanoparticles (LNP) for intravesical delivery. LNP composition is based upon clinically relevant formulations used in RNAi-based therapies consisting of PEG-stabilized unilamellar liposomes built with lipid DLin-KC2-DMA. We confirm p21 induction, cell-cycle arrest, and apoptosis in vitro following treatment with LNP-formulated dsP21-322-2'F (LNP-dsP21-322-2'F) or one of its nonformulated variants. Both 2'-fluoro modification and LNP formulation also improve duplex stability in urine. Intravesical delivery of LNP-dsP21-322-2'F into mouse bladder results in urothelium uptake and extends survival of mice with established orthotopic human bladder cancer. LNP-dsP21-322-2'F treatment also facilitates p21 activation in vivo leading to regression/disappearance of tumors in 40% of the treated mice. Our results provide preclinical proof-of-concept for a novel method to treat bladder cancer by intravesical administration of LNP-formulated RNA duplexes. Cancer Res; 72(19); 5069-79. ©2012 AACR.
    Preview · Article · Aug 2012 · Cancer Research
Show more

We use cookies to give you the best possible experience on ResearchGate. Read our cookies policy to learn more.