title: Combination of a novel HDAC inhibitor OBP-801/YM753 and a PI3K inhibitor LY294002 synergistically induces apoptosis in human endometrial carcinoma cells due to increase of Bim with accumulation of ROS.
abstract: OBJECTIVE
  In most endometrial carcinoma, it has been observed that the PI3K/Akt pathway is abnormally accelerated in association with mutations in PIK3CA and PTEN. The present study aimed to examine the combined effect of a novel histone deacetylase (HDAC) inhibitor OBP-801/YM753 and a PI3K inhibitor LY294002 against human endometrial carcinoma cells.
  
  
  METHODS
  The effects of OBP-801/YM753 and LY294002 on the growth of human endometrial carcinoma HEC-1A cells were examined using WST-8 and colony formation assays. The distribution of the cell cycle or apoptosis was analyzed by flow cytometry. The accumulation of intracellular reactive oxygen species (ROS) was measured with a 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate, acetyl ester (CM-H2DCFDA) dye. The expression of apoptosis-related proteins was investigated by Western blotting. Mice engrafted with 1×10(8) HEC-1A cells were treated with OBP-801/YM753, LY294002 or the combination, and tumor volumes were measured.
  
  
  RESULTS
  The combination of OBP-801/YM753 and LY294002 significantly inhibited the cell growth on comparison with each agent alone and synergistically increased apoptosis with the induction of Bim, a well-known apoptosis inducer. Additionally, the apoptosis induced by the combination was shown to be dependent on intracellular ROS accumulation and Bim induction. Moreover, the apoptosis-inducing effect of OBP-801/YM753 with LY294002 was more potent than that of SAHA with LY294002. Combined treatment with OBP-801/YM753 and LY294002 significantly suppressed tumor growth compared to the control in vivo.
  
  
  CONCLUSIONS
  The combination of OBP-801/YM753 and LY294002 is effective on the inhibition of the growth of HEC-1A cells, and we suggest that this combination is promising a novel therapeutic strategy for endometrial carcinoma.
authors: Department of Molecular-Targeting Cancer Prevention, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan.
authors: Takashi
authors: T
authors: Yoshioka
authors: Shingo
authors: S
authors: Yogosawa
authors: Takeshi
authors: T
authors: Yamada
authors: Jo
authors: J
authors: Kitawaki
authors: Toshiyuki
authors: T
authors: Sakai
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D000072224:Bcl-2-Like Protein 11; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects* / Q000502:physiology; D002867:Chromones / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004357:Drug Synergism; D016889:Endometrial Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D056572:Histone Deacetylase Inhibitors / Q000008:administration & dosage; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D009025:Morpholines / Q000008:administration & dosage; D010456:Peptides, Cyclic / Q000008:administration & dosage; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D016896:Treatment Outcome; D047630:Depsipeptides
chemical_list: D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; D000072224:Bcl-2-Like Protein 11; D014408:Biomarkers, Tumor; D002867:Chromones; D056572:Histone Deacetylase Inhibitors; D008565:Membrane Proteins; D009025:Morpholines; D010456:Peptides, Cyclic; D011518:Proto-Oncogene Proteins; D017382:Reactive Oxygen Species; C000606775:BCL2L11 protein, human; C000606776:Bcl2l11 protein, mouse; C528967:YM753 compound; D047630:Depsipeptides; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one