The use of histone deacetylase inhibitor FK228 and DNA hypomethylation agent 5-azacytidine in human bladder cancer therapy.
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.
Karam
Jose A
JA
Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9110, USA.
Fan
Jinhai
J
Stanfield
Jennifer
J
Richer
Edmond
E
Benaim
Elie A
EA
Frenkel
Eugene
E
Antich
Peter
P
Sagalowsky
Arthur I
AI
Mason
Ralph P
RP
Hsieh
Jer-Tsong
JT
D000818:Animals; D001374:Azacitidine / Q000627:therapeutic use*; D015153:Blotting, Western; D002295:Carcinoma, Transitional Cell / Q000188:drug therapy / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D019175:DNA Methylation; D047630:Depsipeptides / Q000627:therapeutic use*; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D005260:Female; D056572:Histone Deacetylase Inhibitors; D006657:Histones / Q000378:metabolism; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy* / Q000473:pathology; D023041:Xenograft Model Antitumor Assays
C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D047630:Depsipeptides; D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006657:Histones; D016159:Tumor Suppressor Protein p53; C087123:romidepsin; D001374:Azacitidine