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

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 G 2 /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. ' 2007 Wiley-Liss, Inc.Key words: bladder cancer; chemotherapy; histone acetylation; DNA methylationIn the United States, transitional cell carcinoma (TCC) of the bladder is estimated to affect 63,210 persons in 2005, resulting in 13,180 deaths. 1 In recent times, patients with metastatic TCC have experienced improved prognosis; however, the long-term diseasefree survival is still low. 2 Conventional cytotoxic chemotherapy is currently the main treatment for these patients. 3 Several single agents and combinations have been used, but the MVAC (Methotrexate, Vinblastin, Adriamycin and Cisplatin) regimen has been yielding the best results. 3,4 This regimen, however, is not without serious side effects. Treatment-related deaths can occur in up to 4% of patients. 5,6 Still, with the best regimens available, median survival ranges from 13 to 15 months. 4,[6][7][8] The importance of finding alternatives to MVAC, which are at least as effective but with less side effects, has encouraged several investigators to try other chemotherapeutic combinations, such as gemcitabine plus cisplatin 8 and docetaxel plus cisplatin. 9 However, these agents did not prove to be superior to the traditional MVAC regimen. Novel chemotherapeutic regimens are currently needed to decrease the morbidity and mortality of TCC.Epigenetic mechanisms result in changes in gene expression without altering the DNA sequence per se. 10 These changes involve DNA methyl...

Double Stranded-Rna-Mediated Activation of P21 Gene Induced Apoptosis and Cell Cycle Arrest in Renal Cell Carcinoma

“…Similar results have been shown for ectopic expression of p21 or induction of p21 by different mechanisms [22][23][24][25][26][27] . Concomitantly, results of flow cytometry showed that dsP21 transfection caused a G1 arrest, with a significant decrease in S-phase.…”

Effect of Trans-2,3-Dimethoxycinnamoyl Azide on Enhancing Antitumor Activity of Romidepsin on Human Bladder Cancer

“…6B). The induction of p21 seems to be a hallmark of histone deacetylation (32), and p21 expression is associated with the antiproliferative effect of HDACI (11,33). Based on data from this study, we believe that p21 induction is critical for the growth inhibition and apoptosis of TCC.…”

“…Thus, targeting epigenetic machinery with different inhibitors (9,10) has become a new avenue of cancer therapy. Recently, we have shown a potent in vitro growth inhibitory effect of DNA hypomethylating agent (e.g., 5-azacytidine) and romidepsin on several human TCC cell lines (11). Using xenograft models, we concluded that romidepsin is a promising agent for human bladder cancer (11).…”

Histone deacetylase inhibitors in the treatment for multiple myeloma

“…It inhibits HDAC1 and HDAC2 with IC50 of 1.6 and 3.9 nM by noncell base and cell-based assays, respectively [18][19][20][21]. In MM, romidepsine induces apoptosis both in cell lines and primary tumor cells from patients, associated with downregulation of Bcl-2, BCL-xL and Mcl-1 expression [22].…”