title: Romidepsin and Azacitidine Synergize in their Epigenetic Modulatory Effects to Induce Apoptosis in CTCL.
abstract: OBJECTIVE
  Cutaneous T-cell lymphomas (CTCL) are a heterogeneous group of malignancies that despite available therapies commonly relapse. The emergence of combination epigenetic therapies in other hematologic malignancies have made investigation of such combinations in CTCL a priority. Here, we explore the synergistic antiproliferative effects of romidepsin, an HDAC inhibitor, and azacitidine, a demethylating agent, combination in CTCL.
  
  
  METHODS
  The growth inhibition under combination treatment and single agent was explored by the MTT cell viability assay and the Annexin V/propidium iodide (PI) apoptosis assay in different CTCL cell lines and tumor cells derived from Sézary syndrome patients. Quantitative analysis of a dose-effect relationship of romidepsin and azacitidine was done by the CompuSyn software. Investigation of mechanism of action was performed by flow cytometry, immunoblotting, qRT-PCR arrays, and chromatin immunoprecipitation. Global CpG methylation sequencing was utilized to study genome methylation alteration under the treatment modalities.
  
  
  RESULTS
  The combination of romidepsin and azacitidine exerts synergistic antiproliferative effects and induction of apoptosis involving activation of the caspase cascade in CTCL cell lines and tumor cells derived from Sézary syndrome patients. We identified genes that were selectively induced by the combination treatment, such as the tumor suppressor geneRhoBthat is linked to enhanced histone acetylation at its promoter region in parallel with pronounced expression of p21. Global CpG methylation sequencing in a CTCL cell line and tumor cells demonstrated a subset of genes with a unique change in methylation profile in the combination treatment.
  
  
  CONCLUSIONS
  The synergistic antiproliferative effects of romidepsin and azacitidine combination treatment justify further exploration in clinical trials for advanced CTCL.
authors.affiliation: Department of Dermatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Sima
authors.initials: S
authors.lastname: Rozati
authors.affiliation: Department of Dermatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Phil F
authors.initials: PF
authors.lastname: Cheng
authors.affiliation: Department of Dermatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Widmer
authors.affiliation: Department of Dermatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Kazuyasu
authors.initials: K
authors.lastname: Fujii
authors.affiliation: Department of Dermatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Mitchell P
authors.initials: MP
authors.lastname: Levesque
authors.affiliation: Department of Dermatology, University Hospital Zurich, Zurich, Switzerland. reinhard.dummer@usz.ch.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Dummer
mesh_terms: D000107:Acetylation; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001374:Azacitidine / Q000494:pharmacology*; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D016000:Cluster Analysis; D018899:CpG Islands; D019175:DNA Methylation / Q000187:drug effects; D047630:Depsipeptides / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D044127:Epigenesis, Genetic / Q000187:drug effects*; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology; D006657:Histones / Q000378:metabolism; D006801:Humans; D016410:Lymphoma, T-Cell, Cutaneous / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012751:Sezary Syndrome / Q000235:genetics / Q000473:pathology
chemical_list: D000964:Antimetabolites, Antineoplastic; D047630:Depsipeptides; D056572:Histone Deacetylase Inhibitors; D006657:Histones; C087123:romidepsin; D001374:Azacitidine