The use of histone deacetylase inhibitor FK228 and DNA hypomethylation agent 5-azacytidine in human bladder cancer therapy

Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9110, USA.
International Journal of Cancer (Impact Factor: 5.01). 04/2007; 120(8):1795-802. DOI: 10.1002/ijc.22405
Source: PubMed

ABSTRACT The long-term disease-free survival in patients with metastatic transitional cell carcinoma (TCC) is still considerably low. Novel chemotherapeutic agents are needed to decrease the morbidity and mortality of TCC. In this study, we have evaluated several epigenetic modifiers for their therapeutic application in bladder cancer. Both histone deacetylase inhibitors (FK228, TSA) and DNA hypomethylating agent (5-Azacytidine) were tested using in vitro assays such as cell viability, cell cycle analysis and western blot to determine their mechanisms of action. Drug combination experiments were also designed to study any additive or synergistic effects of these agents. In addition, two bladder cancer xenograft models (one subcutaneous and one orthotopic) were employed to assess the therapeutic efficacy of these agents in vivo. Three agents exhibited various growth inhibitory effects on 5 different TCC cell lines in a dose- and time-dependent manner. In addition to G2/M cell cycle arrest, FK228 is more potent in inducting apoptosis than the two other single agents, and combination of both FK228 and 5-Aza further enhances this effect. p21 induction is closely associated with FK228 or TSA but not 5-Aza, which is mediated via p53-independent pathway. Consistent with in vitro results, FK228 exhibited a significant in vivo growth inhibition of TCC tumor in both subcutaneous and orthotopic xenograft models. FK228 is a potent chemotherapeutic agent for TCC in vivo with minimal undesirable side effects. The elevated p21 level mediated via p53 independent pathway is a hallmark of FK228 mechanism of action.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Transitional cell (urothelial) carcinoma of the bladder is the second most common urologic malignancy and is one of the best understood neoplasms, with relatively well-defined pathogenetic pathways, natural history, and tumor biology. Conventional clinical and pathologic parameters are widely used to grade and stage tumors and to predict clinical outcome of transitional cell carcinoma; but the predictive ability of these parameters is limited, and there is a lack of indices that could allow prospective assessment of risk for individual patients. In the last decade, a wide range of candidate biomarkers representing key pathways in carcinogenesis have been reported to be clinically relevant and potentially useful as diagnostic and prognostic molecular markers, and as potential therapeutic targets. The use of molecular markers has facilitated the development of novel and more accurate diagnostic, prognostic, and therapeutic strategies. FGFR3 and TP53 mutations have been recognized as key genetic pathways in the carcinogenesis of transitional cell carcinoma. FGFR3 appears to be the most frequently mutated oncogene in transitional cell carcinoma; its mutation is strongly associated with low tumor grade, early stage, and low recurrence rate, which confer a better overall prognosis. In contrast, TP53 mutations are associated with higher tumor grade, more advanced stage, and more frequent tumor recurrences. These molecular markers offer the potential to characterize individual urothelial neoplasms more completely than is possible by histologic evaluation alone. Areas in which molecular markers may prove valuable include prediction of tumor recurrence, molecular staging of transitional cell carcinoma, detection of lymph node metastasis and circulating cancer cells, identification of therapeutic targets, and prediction of response to therapy. With accumulating molecular knowledge of transitional cell carcinoma, we are closer to the goal of bridging the gap between molecular findings and clinical outcomes. Assessment of key genetic pathways and expression profiles could ultimately establish a set of molecular markers to predict the biological nature of tumors and to establish new standards for molecular tumor grading, classification, and prognostication. The main focus of this review is to discuss clinically relevant biomarkers that might be useful in the management of transitional cell carcinoma and to provide approaches in the analysis of molecular pathways that influence the clinical course of bladder cancer.
    Human pathology 11/2010; 42(4):455-81. DOI:10.1016/j.humpath.2010.07.007 · 2.81 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Trichostatin A (TSA) is a potent histone deacetylase inhibitor and has demonstrated significant antitumor activity against a variety of cancer cell lines. Type I interferons have also shown significant antitumor as well as antiangiogenic activity. In this study, we examined the effectiveness of combination therapy of TSA and interferon beta (IFN-beta) on human neuroblastoma cells in vitro and in vivo using a murine model of retroperitoneal neuroblastoma. For in vitro experiments, plated human neuroblastoma cells (NB-1643 and NB-1691) were treated with vehicle or with IFN-beta, TSA, or both for 24 hours. Cytotoxicity was assessed by counting cells and expressing the results as a percentage of controls. Expression of the tumor suppressor p21(Waf1) was assessed by Western blot. For in vivo experiments, retroperitoneal neuroblastomas were established in severe combined immune deficiency (SCID) mice. Interferon beta was given using a gene therapy approach, administering 1.5 x 10(10) particles of an adeno-associated virus vector encoding human IFN-beta (AAV hIFN-beta) via tail vein as a single dose per mouse. Trichostatin A was given at a dose of 5 mg/kg every 48 hours subcutaneously. Treatment groups included controls, AAV hIFN-beta alone, TSA alone, and AAV hIFN-beta together with TSA. Tumor volume was assessed 2 weeks after the treatment began. After 24 hours, treatment with IFN-beta, TSA, and a combination of both resulted in a 45.3%, 68.1%, and 75% reduction in cell count relative to controls in the NB-1691 cell line. In the NB-1643 line, cell counts were reduced by 23%, 58%, and 62.3% respectively. In addition, NB-1691 cells treated with TSA showed increased expression of p21(Waf1) on Western blot. For in vivo experiments, control-, AAV hIFN-beta-, TSA-, and combination-treated tumors had the following final volumes: 1577.7 +/- 264.2 mm(3) (n = 3); 128.5 +/- 74.4 mm(3) (n = 4; P = .0001); 1248.7 +/- 673.9 mm(3) (n = 4; P = .48); and 127.5 +/- 36.8 mm(3) (n = 4; P = .0007), respectively. Neuroblastoma, because of its unique biology, continues to be a challenging tumor to treat, and many times these tumors are refractory to standard chemotherapeutic regimens. These data show that both TSA and IFN-beta inhibit neuroblastoma growth and that the combination may potentially provide a unique way to treat this difficult disease.
    Journal of Pediatric Surgery 02/2008; 43(1):177-82; discussion 182-3. DOI:10.1016/j.jpedsurg.2007.09.048 · 1.31 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Discrete chemical modifications of the chromatin (DNA and primarily histones) can regulate gene expression or repression and can be transmitted to the descent (cells or organisms) thanks to an epigenetic memory. These modifications involve histone post-translational modifications, DNA methylation at CpG islands and small nuclear RNAs processes. They play fundamental roles in cell proliferation and differentiation. These two processes are crucial in particular during embryonic development, X chromosome inactivation in females, genomic imprinting, gene bookmarking, cell reprogramming, position effect and silencing of retroviral elements. While, only one major DNA modification is known, more than 150 post-translation modifications of histones have been reported, including methylations, acetylations, ubiquitinations, SUMOylations and phosphorylations. How these modifications are inherited from mother cells to daughter cells or from an organism to its descent remains a major scientific challenge. We propose here a macro-molecular complex, called ECREM for "Epigenetic Code REplication Machinery", as being involved in the inheritance of the epigenetic code. The composition of ECREM may vary in a spatio-temporal manner according to the chromatin state, the cell phenotype and the development stage. We describe the members of ECREM, responsible for the epigenetic code inheritance, i.e., enzymes involved in DNA methylation and histone post-translational modifications. Some of them, such as DNA methyltransferases (DNMTs), histone acetyltransferases (HATs) and histone deacetylases (HDACS including sirtuins), have been found to be deregulated in several types of pathologies and are already targeted by inhibitors. ECREM, thus, appears to be an interesting complex to be investigated in order to find new drugs for cancer, metabolic, neuro-degenerative and inflammatory diseases therapy.
    Current Medicinal Chemistry 02/2007; 14(25):2629-41. DOI:10.2174/092986707782023244 · 3.72 Impact Factor