Suberoylanilide hydroxamic acid (SAHA) enhances olaparib activity by targeting homologous recombination DNA repair in ovarian cancer

  • Author Footnotes
    1 Contributed equally.
    Panagiotis A. Konstantinopoulos
    1 Contributed equally.
    Department of Medical Oncology, Medical Gynecologic Oncology Program, Dana Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
    Search for articles by this author
  • Author Footnotes
    1 Contributed equally.
    Andrew J. Wilson
    1 Contributed equally.
    Department of Obstetrics & Gynecology, Division of Gynecologic Oncology, Vanderbilt University Medical Center, Nashville, TN, USA
    Search for articles by this author
  • Jeanette Saskowski
    Department of Obstetrics & Gynecology, Division of Gynecologic Oncology, Vanderbilt University Medical Center, Nashville, TN, USA
    Search for articles by this author
  • Erica Wass
    Department of Obstetrics & Gynecology, Division of Gynecologic Oncology, Vanderbilt University Medical Center, Nashville, TN, USA
    Search for articles by this author
  • Dineo Khabele
    Corresponding author at: Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, Vanderbilt University, 21st Avenue South, B-1100 Medical Center North, Nashville, TN 37232, USA. Fax: +1 615 343 8403.
    Department of Obstetrics & Gynecology, Division of Gynecologic Oncology, Vanderbilt University Medical Center, Nashville, TN, USA

    Vanderbilt-Ingram Cancer Center, Nashville, TN, USA
    Search for articles by this author
  • Author Footnotes
    1 Contributed equally.


      • SAHA downregulates homologous recombination pathway genes in ovarian cancer cells.
      • Formation of RAD51 foci is inhibited by SAHA alone and combined with olaparib.
      • Anti-tumor effects of olaparib in vitro and in vivo are enhanced by SAHA.



      Approximately 50% of serous epithelial ovarian cancers (EOC) contain molecular defects in homologous recombination (HR) DNA repair pathways. Poly(ADP-ribose) polymerase inhibitors (PARPi) have efficacy in HR-deficient, but not in HR-proficient, EOC tumors as a single agent. Our goal was to determine whether the histone deacetylase inhibitor, suberoylanilide hydroxamic acid (SAHA), can sensitize HR-proficient ovarian cancer cells to the PARPi AZD-2281 (olaparib).


      Ovarian cancer cell lines (SKOV-3, OVCAR-8, NCI/ADR-Res, UWB1.289 BRCA1null and UWB1.289 + BRCA1 wild-type) were treated with saline vehicle, olaparib, SAHA or olaparib/SAHA. Sulforhodamine B (SRB) assessed cytotoxicity and immunofluorescence and Western blot assays assessed markers of apoptosis (cleaved PARP) and DNA damage (pH2AX and RAD51). Drug effects were also tested in SKOV-3 xenografts in Nude mice. Affymetrix microarray experiments were performed in vehicle and SAHA-treated SKOV-3 cells.


      In a microarray analysis, SAHA induced coordinated down-regulation of HR pathway genes, including RAD51 and BRCA1. Nuclear co-expression of RAD51 and pH2AX, a marker of efficient HR repair, was reduced approximately 40% by SAHA treatment alone and combined with olaparib. SAHA combined with olaparib induced apoptosis and pH2AX expression to a greater extent than either drug alone. Olaparib reduced cell viability at increasing concentrations and SAHA enhanced these effects in 4 of 5 cell lines, including BRCA1 null and wild-type cells, in vitro and in SKOV-3 xenografts in vivo.


      These results provide preclinical rationale for targeting DNA damage response pathways by combining small molecule PARPi with HDACi as a mechanism for reducing HR efficiency in ovarian cancer.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Gynecologic Oncology
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


      1. Integrated genomic analyses of ovarian carcinoma.
        Nature. 2011; 474: 609-615
        • Alsop K.
        • Fereday S.
        • Meldrum C.
        • Defazio A.
        • Emmanuel C.
        • George J.
        • et al.
        BRCA mutation frequency and patterns of treatment response in BRCA mutation-positive women with ovarian cancer: a report from the Australian Ovarian Cancer Study Group.
        J Clin Oncol. 2012; 30: 2654-2663
        • Audeh M.W.
        • Carmichael J.
        • Penson R.T.
        • Friedlander M.
        • Powell B.
        • Bell-McGuinn K.M.
        • et al.
        Oral poly(ADP-ribose) polymerase inhibitor olaparib in patients with BRCA1 or BRCA2 mutations and recurrent ovarian cancer: a proof-of-concept trial.
        Lancet. 2010; 376: 245-251
        • Fong P.C.
        • Boss D.S.
        • Yap T.A.
        • Tutt A.
        • Wu P.
        • Mergui-Roelvink M.
        • et al.
        Inhibition of poly(ADP-ribose) polymerase in tumors from BRCA mutation carriers.
        N Engl J Med. 2009; 361: 123-134
        • Fong P.C.
        • Yap T.A.
        • Boss D.S.
        • Carden C.P.
        • Mergui-Roelvink M.
        • Gourley C.
        • et al.
        Poly(ADP)-ribose polymerase inhibition: frequent durable responses in BRCA carrier ovarian cancer correlating with platinum-free interval.
        J Clin Oncol. 2010; 28: 2512-2519
        • Gelmon K.A.
        • Tischkowitz M.
        • Mackay H.
        • Swenerton K.
        • Robidoux A.
        • Tonkin K.
        • et al.
        Olaparib in patients with recurrent high-grade serous or poorly differentiated ovarian carcinoma or triple-negative breast cancer: a phase 2, multicentre, open-label, non-randomised study.
        Lancet Oncol. 2011; 12: 852-861
        • Ledermann J.
        • Harter P.
        • Gourley C.
        • Friedlander M.
        • Vergote I.
        • Rustin G.
        • et al.
        Olaparib maintenance therapy in platinum-sensitive relapsed ovarian cancer.
        N Engl J Med. 2012; 366: 1382-1392
        • Bryant H.E.
        • Schultz N.
        • Thomas H.D.
        • Parker K.M.
        • Flower D.
        • Lopez E.
        • et al.
        Specific killing of BRCA2-deficient tumours with inhibitors of poly(ADP-ribose) polymerase.
        Nature. 2005; 434: 913-917
        • Farmer H.
        • McCabe N.
        • Lord C.J.
        • Tutt A.N.
        • Johnson D.A.
        • Richardson T.B.
        • et al.
        Targeting the DNA repair defect in BRCA mutant cells as a therapeutic strategy.
        Nature. 2005; 434: 917-921
        • Haince J.F.
        • Rouleau M.
        • Hendzel M.J.
        • Masson J.Y.
        • Poirier G.G.
        Targeting poly(ADP-ribosyl)ation: a promising approach in cancer therapy.
        Trends Mol Med. 2005; 11: 456-463
        • Chen A.
        PARP inhibitors: its role in treatment of cancer.
        Chin J Cancer. 2011; 30: 463-471
        • Saleh-Gohari N.
        • Bryant H.E.
        • Schultz N.
        • Parker K.M.
        • Cassel T.N.
        • Helleday T.
        Spontaneous homologous recombination is induced by collapsed replication forks that are caused by endogenous DNA single-strand breaks.
        Mol Cell Biol. 2005; 25: 7158-7169
        • Arnaudeau C.
        • Lundin C.
        • Helleday T.
        DNA double-strand breaks associated with replication forks are predominantly repaired by homologous recombination involving an exchange mechanism in mammalian cells.
        J Mol Biol. 2001; 307: 1235-1245
        • Banath J.P.
        • Klokov D.
        • MacPhail S.H.
        • Banuelos C.A.
        • Olive P.L.
        Residual gammaH2AX foci as an indication of lethal DNA lesions.
        BMC Cancer. 2010; 10: 4
        • Kaye S.B.
        • Lubinski J.
        • Matulonis U.
        • Ang J.E.
        • Gourley C.
        • Karlan B.Y.
        • et al.
        Phase II, open-label, randomized, multicenter study comparing the efficacy and safety of olaparib, a poly (ADP-ribose) polymerase inhibitor, and pegylated liposomal doxorubicin in patients with BRCA1 or BRCA2 mutations and recurrent ovarian cancer.
        J Clin Oncol. 2011; 30: 372-379
        • Wilson A.J.
        • Lalani A.S.
        • Wass E.
        • Saskowski J.
        • Khabele D.
        Romidepsin (FK228) combined with cisplatin stimulates DNA damage-induced cell death in ovarian cancer.
        Gynecol Oncol. 2012; 127: 579-586
        • Gregoretti I.V.
        • Lee Y.M.
        • Goodson H.V.
        Molecular evolution of the histone deacetylase family: functional implications of phylogenetic analysis.
        J Mol Biol. 2004; 338: 17-31
        • Koprinarova M.
        • Botev P.
        • Russev G.
        Histone deacetylase inhibitor sodium butyrate enhances cellular radiosensitivity by inhibiting both DNA nonhomologous end joining and homologous recombination.
        DNA Repair (Amst). 2011; 10: 970-977
        • Adimoolam S.
        • Sirisawad M.
        • Chen J.
        • Thiemann P.
        • Ford J.M.
        • Buggy J.J.
        HDAC inhibitor PCI-24781 decreases RAD51 expression and inhibits homologous recombination.
        Proc Natl Acad Sci U S A. 2007; 104: 19482-19487
        • Ladd B.
        • Ackroyd J.J.
        • Hicks J.K.
        • Canman C.E.
        • Flanagan S.A.
        • Shewach D.S.
        Inhibition of homologous recombination with vorinostat synergistically enhances ganciclovir cytotoxicity.
        DNA Repair (Amst). 2013; 12: 1114-1121
        • Mann B.S.
        • Johnson J.R.
        • Cohen M.H.
        • Justice R.
        • Pazdur R.
        FDA approval summary: vorinostat for treatment of advanced primary cutaneous T-cell lymphoma.
        Oncologist. 2007; 12: 1247-1252
        • Mann B.S.
        • Johnson J.R.
        • He K.
        • Sridhara R.
        • Abraham S.
        • Booth B.P.
        • et al.
        Vorinostat for treatment of cutaneous manifestations of advanced primary cutaneous T-cell lymphoma.
        Clin Cancer Res. 2007; 13: 2318-2322
        • Khabele D.
        • Son D.S.
        • Parl A.K.
        • Goldberg G.L.
        • Augenlicht L.H.
        • Mariadason J.M.
        • et al.
        Drug-induced inactivation or gene silencing of class I histone deacetylases suppresses ovarian cancer cell growth: implications for therapy.
        Cancer Biol Ther. 2007; 6: 795-801
        • Wilson A.J.
        • Holson E.
        • Wagner F.
        • Zhang Y.L.
        • Fass D.M.
        • Haggarty S.J.
        • et al.
        The DNA damage mark pH2AX differentiates the cytotoxic effects of small molecule HDAC inhibitors in ovarian cancer cells.
        Cancer Biol Ther. 2011; 12: 484-493
        • Lorenzi P.L.
        • Reinhold W.C.
        • Varma S.
        • Hutchinson A.A.
        • Pommier Y.
        • Chanock S.J.
        • et al.
        DNA fingerprinting of the NCI-60 cell line panel.
        Mol Cancer Ther. 2009; 8: 713-724
        • Scudiero D.A.
        • Monks A.
        • Sausville E.A.
        Cell line designation change: multidrug-resistant cell line in the NCI anticancer screen.
        J Natl Cancer Inst. 1998; 90: 862
        • DelloRusso C.
        • Welcsh P.L.
        • Wang W.
        • Garcia R.L.
        • King M.C.
        • Swisher E.M.
        Functional characterization of a novel BRCA1-null ovarian cancer cell line in response to ionizing radiation.
        Mol Cancer Res. 2007; 5: 35-45
        • Effron B.
        • Tibshirani R.
        On testing the significance of sets of genes.
        Ann Appl Stat. 2007; 1: 107-129
        • Chou T.C.
        • Talalay P.
        Quantitative analysis of dose-effect relationships: the combined effects of multiple drugs or enzyme inhibitors.
        Adv Enzyme Regul. 1984; 22: 27-55
        • Wilson A.J.
        • Arango D.
        • Mariadason J.M.
        • Heerdt B.G.
        • Augenlicht L.H.
        TR3/Nur77 in colon cancer cell apoptosis.
        Cancer Res. 2003; 63: 5401-5407
        • Wilson A.J.
        • Byun D.S.
        • Nasser S.
        • Murray L.B.
        • Ayyanar K.
        • Arango D.
        • et al.
        HDAC4 promotes growth of colon cancer cells via repression of p21.
        Mol Biol Cell. 2008; 19: 4062-4075
        • Rauh-Adelmann C.
        • Lau K.M.
        • Sabeti N.
        • Long J.P.
        • Mok S.C.
        • Ho S.M.
        Altered expression of BRCA1, BRCA2, and a newly identified BRCA2 exon 12 deletion variant in malignant human ovarian, prostate, and breast cancer cell lines.
        Mol Carcinog. 2000; 28: 236-246
        • Zhou C.
        • Huang P.
        • Liu J.
        The carboxyl-terminal of BRCA1 is required for subnuclear assembly of RAD51 after treatment with cisplatin but not ionizing radiation in human breast and ovarian cancer cells.
        Biochem Biophys Res Commun. 2005; 336: 952-960
        • Chen X.
        • Wong P.
        • Radany E.H.
        • Stark J.M.
        • Laulier C.
        • Wong J.Y.
        Suberoylanilide hydroxamic acid as a radiosensitizer through modulation of RAD51 protein and inhibition of homology-directed repair in multiple myeloma.
        Mol Cancer Res. 2012; 10: 1052-1064
        • Suzuki T.
        • Miyata N.
        Non-hydroxamate histone deacetylase inhibitors.
        Curr Med Chem. 2005; 12: 2867-2880
        • Modesitt S.C.
        • Sill M.
        • Hoffman J.S.
        • Bender D.P.
        A phase II study of vorinostat in the treatment of persistent or recurrent epithelial ovarian or primary peritoneal carcinoma: a Gynecologic Oncology Group study.
        Gynecol Oncol. 2008; 109: 182-186
        • Bhaskara S.
        • Chyla B.J.
        • Amann J.M.
        • Knutson S.K.
        • Cortez D.
        • Sun Z.W.
        • et al.
        Deletion of histone deacetylase 3 reveals critical roles in S phase progression and DNA damage control.
        Mol Cell. 2008; 30: 61-72
        • Bhaskara S.
        • Knutson S.K.
        • Jiang G.
        • Chandrasekharan M.B.
        • Wilson A.J.
        • Zheng S.
        • et al.
        Hdac3 is essential for the maintenance of chromatin structure and genome stability.
        Cancer Cell. 2010; 18: 436-447
        • Bradner J.E.
        • West N.
        • Grachan M.L.
        • Greenberg E.F.
        • Haggarty S.J.
        • Warnow T.
        • et al.
        Chemical phylogenetics of histone deacetylases.
        Nat Chem Biol. 2010; 6: 238-243