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

Gynecol Oncol. 2013 May;129(2):425-32. doi: 10.1016/j.ygyno.2013.02.008. Epub 2013 Feb 9.


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.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / administration & dosage
  • Antineoplastic Combined Chemotherapy Protocols / pharmacology*
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use
  • Apoptosis / drug effects*
  • Apoptosis / physiology
  • Apoptosis Regulatory Proteins / metabolism*
  • Bcl-2-Like Protein 11
  • Biomarkers, Tumor / metabolism*
  • Blotting, Western
  • Cell Line, Tumor
  • Cell Survival / drug effects*
  • Cell Survival / physiology
  • Chromones / administration & dosage
  • Dose-Response Relationship, Drug
  • Drug Administration Schedule
  • Drug Synergism
  • Endometrial Neoplasms / drug therapy*
  • Endometrial Neoplasms / metabolism
  • Female
  • Flow Cytometry
  • Histone Deacetylase Inhibitors / administration & dosage
  • Humans
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Inbred BALB C
  • Morpholines / administration & dosage
  • Peptides, Cyclic / administration & dosage
  • Proto-Oncogene Proteins / metabolism*
  • Reactive Oxygen Species / metabolism*
  • Treatment Outcome


  • Antineoplastic Agents
  • Apoptosis Regulatory Proteins
  • BCL2L11 protein, human
  • Bcl-2-Like Protein 11
  • Bcl2l11 protein, mouse
  • Biomarkers, Tumor
  • Chromones
  • Histone Deacetylase Inhibitors
  • Membrane Proteins
  • Morpholines
  • Peptides, Cyclic
  • Proto-Oncogene Proteins
  • Reactive Oxygen Species
  • YM753 compound
  • 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one