Investigational New Drugs

, Volume 28, Issue 1, pp 20–25 | Cite as

Anti-proliferative effects of simocyclinone D8 (SD8), a novel catalytic inhibitor of topoisomerase II

  • Ahad A. Sadiq
  • Manish R. Patel
  • Blake A. Jacobson
  • Marco Escobedo
  • Keith Ellis
  • Lisa M. Oppegard
  • Hiroshi Hiasa
  • Robert A. Kratzke
Preclinical Studies


Introduction: Simocyclinone D-8 (SD8), a semi-synthetic compound derived from yeast, has been shown to decrease the proliferation of MCF-7 breast cancer cells. It has been shown to be a potent bacterial DNA gyrase inhibitor, a homologue of human topoisomerase II (hTopoII). We tested SD8 activity alone and in combination with cisplatin against malignant mesothelioma (MM) and non-small cell cancer (NSCLC) cell lines. Methods: Inhibition of hTopoII supercoiling function by SD8 and a known hTopoII poison, etoposide, were done by in vitro assay using purified hTopoII and kinetoplast DNA as the substrate. The DNA products were analyzed by agarose gel electrophoresis after treatment with increasing concentrations of each drug. Mesothelioma cell lines (H2373, H2461 and H2596) and NSCLC cell lines (H2030, H460, and H2009) grown in RPMI with 10% calf serum were used. Non-malignant mesothelial cells, LP9, were grown in 1:1 ratio of MCDB:199E medium supplemented with 15% calf serum, 0.4 μg/mL hydrocortisone, and 15 ng/mL epidermal grown factor. Cell proliferation assays were performed in 96-well plates using the CCK-8 kit (Dojindo inc.). Cells were treated for 72 h with various SD8 concentrations and controls containing equal volume of the vehicle, DMSO. Treated cells were assayed for the induction of apoptosis with poly ADP-ribose polymerase-1 (PARP) cleavage assay. Results: Biochemical assays revealed that the IC50 for hTopoII inhibition was 100 μM for SD8 and 400 μM for etoposide. SD8 inhibited hTopoII function without inducing DNA cleavage events. SD8 inhibited the growth of NSCLC and Mesothelioma cells with IC50 ranging from 75–125 μM. Furthermore, SD8 was not toxic to non-transformed primary mesothelial cell line, LP9 at the IC50 doses. SD8 induced apoptosis in all cell lines tested. Conclusions: SD8 inhibits hTopoII in vitro without inducing DNA strands breaks and has significant activity against NSCLC and MM cell lines. While doses required for SD8 anticancer activity are unlikely to be achieved in vivo, chemical modifications to SD8 to increase its potency could lead to improved therapies for these diseases.


Topoisomerasell Mesothelioma Lung cancer 



We thank Hans-Peter Fiedler for expertise and advice on the fermentation, isolation, and purification of SD8. KE thanks Gunda Georg of the University of Minnesota Department of Medicinal Chemistry for financial support. ME was supported by the Summer Research Training Program at the University of Minnesota Medical School (R25HL088728; C. Campbell, PI). MP was supported by 5T32HL07062 (Division of Hematology-Oncology-Transplant, University of Minnesota, G. Vercellotti PI).


  1. 1.
    Akimitsu N, Kamura K, Tone S, Sakaguchi A, Kikuchi A, Hamamoto H, Sekimizu K (2003) Induction of apoptosis by depletion of DNA topoisomerase IIalpha in mammalian cells. Biochem Biophys Res Commun 307:301–307 doi: 10.1016/S0006-291X(03)01169-0 CrossRefPubMedGoogle Scholar
  2. 2.
    Azarova AM, Lyu YL, Lin CP, Tsai YC, Lau JY, Wang JC, Liu LF (2007) Roles of DNA topoisomerase II isozymes in chemotherapy and secondary malignancies. Proc Natl Acad Sci U S A 104:11014–11019 doi: 10.1073/pnas.0704002104 CrossRefPubMedGoogle Scholar
  3. 3.
    Burden DA, Osheroff N (1998) Mechanism of action of eukaryotic topoisomerase II and drugs targeted to the enzyme. Biochim Biophys Acta 1400:139–154PubMedGoogle Scholar
  4. 4.
    Davies SL, Bergh J, Harris AL, Hickson ID (1997) Response to ICRF-159 in cell lines resistant to cleavable complex-forming topoisomerase II inhibitors. Br J Cancer 75:816–821PubMedGoogle Scholar
  5. 5.
    de Jong RS, Mulder NH, Uges DR, Sleijfer DT, Hoppener FJ, Groen HJ, Willemse PH, van der Graaf WT, de Vries EG (1999) Phase I and pharmacokinetic study of the topoisomerase II catalytic inhibitor fostriecin. Br J Cancer 79:882–887 doi: 10.1038/sj.bjc.6690141 CrossRefPubMedGoogle Scholar
  6. 6.
    Fournel S, Genestier L, Rouault JP, Lizard G, Flacher M, Assossou O, Revillard JP (1995) Apoptosis without decrease of cell DNA content. FEBS Lett 367:188–192 doi: 10.1016/0014-5793(95)00532-E CrossRefPubMedGoogle Scholar
  7. 7.
    Fridman R, Giaccone G, Kanemoto T, Martin GR, Gazdar AF, Mulshine JL (1990) Reconstituted basement mebrane (matrigel) and laminin can enhance the tumorigenicity and the drug resistance of small cell lung cancer cell lines. Proc Natl Acad Sci U S A 87:6698–6702 doi: 10.1073/pnas.87.17.6698 CrossRefPubMedGoogle Scholar
  8. 8.
    Goodell JR, Ougolkov AV, Hiasa H, Kaur H, Remmel R, Billadeau DD, Ferguson DM (2008) Acridine-based agents with topoisomerase II activity inhibit pancreatic cancer cell proliferation and induce apoptosis. J Med Chem 51:179–182 doi: 10.1021/jm701228e CrossRefPubMedGoogle Scholar
  9. 9.
    Hande KR (1998) Clinical applications of anticancer drugs targeted to topoisomerase II. Biochim Biophys Acta 1400:173–184PubMedGoogle Scholar
  10. 10.
    Khelifa T, Beck WT (1999) Merbarone, a catalytic inhibitor of DNA topoisomerase II, induces apoptosis in CEM cells through activation of ICE/CED-3-like protease. Mol Pharmacol 55:548–556PubMedGoogle Scholar
  11. 11.
    Kizaki H, Onishi Y (1997) Topoisomerase II inhibitor-induced apoptosis in thymocytes and lymphoma cells. Adv Enzyme Regul 37:403–423 doi: 10.1016/S0065-2571(96)00014-3 CrossRefPubMedGoogle Scholar
  12. 12.
    Larsen AK, Escargueil AE, Skladanowski A (2003) Catalytic topoisomerase II inhibitors in cancer therapy. Pharmacol Ther 99:167–181 doi: 10.1016/S0163-7258(03)00058-5 CrossRefPubMedGoogle Scholar
  13. 13.
    Oizumi S, Isobe H, Ogura S, Ishida T, Yamazaki K, Nishimura M, Kawakami Y, Dosaka-Akita H (2002) Topoisomerase inhibitor-induced apoptosis accompanied by down-regulation of Bcl-2 in human lung cancer cells. Anticancer Res 22:4029–4037PubMedGoogle Scholar
  14. 14.
    Patel MR, Jacobson BA, De A, Frizelle SP, Janne P, Thumma SC, Whitson BA, Farassati F, Kratzke RA (2007) Ras pathway activation in malignant mesothelioma. J Thorac Oncol 2:789–795 doi: 10.1097/JTO.0b013e31811f3aab CrossRefPubMedGoogle Scholar
  15. 15.
    Pritchard KI, Messersmith H, Elavathil L, Trudeau M, O’Malley F, Dhesy-Thind B (2008) HER-2 and topoisomerase II as predictors of response to chemotherapy. J Clin Oncol 26:736–744 doi: 10.1200/JCO.2007.15.4716 CrossRefPubMedGoogle Scholar
  16. 16.
    Schiller JH, Harrington D, Belani CP, Langer C, Sandler A, Krook J, Zhu J, Johnson DH (2002) Comparison of four chemotherapy regimens for advanced non-small-cell lung cancer. N Engl J Med 346:92–98 doi: 10.1056/NEJMoa011954 CrossRefPubMedGoogle Scholar
  17. 17.
    Schimana J, Fiedler HP, Groth I, Sussmuth R, Beil W, Walker M, Zeeck A (2000) Simocyclinones, novel cytostatic angucyclinone antibiotics produced by Streptomyces antibioticus Tu 6040. I. Taxonomy, fermentation, isolation and biological activities. J Antibiot (Tokyo) 53:779–787Google Scholar
  18. 18.
    Skubitz KM (2002) Phase II trial of pegylated-liposomal doxorubicin (Doxil) in mesothelioma. Cancer Invest 20:693–699 doi: 10.1081/CNV-120003538 CrossRefPubMedGoogle Scholar
  19. 19.
    Vogelzang NJ, Porta C, Mutti L (2005) New agents in the management of advanced mesothelioma. Semin Oncol 32:336–350 doi: 10.1053/j.seminoncol.2005.02.010 CrossRefPubMedGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Ahad A. Sadiq
    • 1
  • Manish R. Patel
    • 1
  • Blake A. Jacobson
    • 1
  • Marco Escobedo
    • 1
  • Keith Ellis
    • 2
  • Lisa M. Oppegard
    • 3
  • Hiroshi Hiasa
    • 3
  • Robert A. Kratzke
    • 1
  1. 1.Division of Hematology-Oncology-Transplant, Department of MedicineUniversity of Minnesota Medical SchoolMinneapolisUSA
  2. 2.Department of Medicinal Chemistry and the Institute for Therapeutic Discovery and Development, College of PharmacyUniversity of MinnesotaMinneapolisUSA
  3. 3.Department of PharmacologyUniversity of Minnesota Medical SchoolMinneapolisUSA

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