JCT  Vol.5 No.4 , April 2014
Base Excision Repair Inhibition by Methoxyamine Impairs Growth and Sensitizes Osteosarcoma Cells to Conventional Treatments

The outcome of patients with osteosarcoma has not significantly improved in the last three decades. Therefore, there is still a need for the development of more effective therapeutic strategies. Methoxyamine (MX) is a base excision repair (BER) inhibitor that has shown anticancer potential by sensitizing a variety of tumor cells to ionizing radiation and chemotherapeutic drugs. In the present study, the in vitro antiproliferative effects of MX were evaluated in two osteosarcoma cell lines, HOS and MG-63. Evaluation of the influence on radiosensitivity and drug interactions in simultaneous treatments with methotrexate, doxorubicin, and cisplatin was also performed. Exposure to MX significantly decreased cell proliferation and mediated a substantial increase of apoptosis. Moreover, our results showed that MX synergized with ionizing radiation in both cell lines while potentiated the antitumor effects of cisplatin and methotrexate. Altogether, the results presented herein demonstrate the feasibility of inhibiting the BER pathway, which may in future be a promising strategy for overcoming intrinsic tumor resistance and to improve the outcome of patients with osteosarcoma.

Cite this paper
Montaldi, A. , Pezuk, J. , Sakamoto-Hojo, E. , Tone, L. and Brassesco, M. (2014) Base Excision Repair Inhibition by Methoxyamine Impairs Growth and Sensitizes Osteosarcoma Cells to Conventional Treatments. Journal of Cancer Therapy, 5, 307-314. doi: 10.4236/jct.2014.54037.
[1]   Raymond, A.K., Ayala, A.G. and Knuutila, S. (2002) Conventional Osteosarcoma. In: Fletcher, C.D.M., Unni, K.K. and Mertens, F. (Eds.), Pathology and Genetics of Tumours of Soft Tissue and Bone. World Health Organization Classification of Tumours. IARC Press, Lyon.

[2]   Jaffe, N. (2009) Osteosarcoma: Review of the Past, Impact on the Future. The American Experience. Cancer Treatment and Research, 152, 239-262. http://dx.doi.org/10.1007/978-1-4419-0284-9_12

[3]   Liu, L. and Gerson, S.L. (2004) Therapeutic Impact of Methoxyamine: Blocking Repair of Abasic Sites in the Base Excision Repair Pathway. Current Opinion in Investigational Drugs, 5, 623-627.

[4]   Liu, L., Nakatsuru, Y. and Gerson, S.L. (2002) Base Excision Repair as a Therapeutic Target in Colon Cancer. Clinical Cancer Research, 8, 2985-2991.

[5]   Fishel, M.L., He, Y., Smith, M.L., et al. (2007) Manipulation of Base Excision Repair to Sensitize Ovarian Cancer Cells to Alkylating Agent Temozolomide. Clinical Cancer Research, 13, 260-267. http://dx.doi.org/10.1158/1078-0432.CCR-06-1920

[6]   Montaldi, A.P. and Sakamoto-Hojo, E.T. (2013) Methoxyamine Sensitizes the Resistant Glioblastoma T98G Cell Line to the Alkylating Agent Temozolomide. Clinical and Experimental Medicine, 13, 279-288. http://dx.doi.org/10.1007/s10238-012-0201-x

[7]   Yan, T., Seo, Y., Schupp, J.E., et al. (2006) Methoxyamine Potentiates Iododeoxyuridine-Induced Radiosensitization by Altering Cell Cycle Kinetics and Enhancing Senescence. Molecular Cancer Therapeutics, 5, 893-902. http://dx.doi.org/10.1158/1535-7163.MCT-05-0364

[8]   Chou, T.C. and Talalay, P. (1984) Quantitative Analysis of Dose-Effect Relationships: The Combined Effects of Multiple Drugs or Enzyme Inhibitors. Advances in Enzyme Regulation, 22, 27-55.

[9]   Loeb, L.A. (1985) Apurinic Sites as Mutagenic Intermediates. Cell, 40, 483-484.

[10]   Krokan, H.E., Standal, R. and Slupphaug, G. (1997) DNA Glycosylases in the Base Excision Repair of DNA. Biochemical Journal, 325, 1-16.

[11]   Boiteux, S. and Guillet, M. (2004) Abasic Sites in DNA: Repair and Biological Consequences in Saccharomyces cerevisiae. DNA Repair (Amst), 3, 1-12. http://dx.doi.org/10.1016/j.dnarep.2003. 10.002

[12]   Hu, H.Y., Horton, J.K., Gryk, M.R., et al. (2004) Identification of Small Molecule Synthetic Inhibitors of DNA Polymerase Beta by NMR Chemical Shift Mapping. Journal of Biological Chemistry, 279, 39736-39744. http://dx.doi.org/10.1074/jbc.M402842200

[13]   Naidu, M.D., Mason, J.M., Pica, R.V., et al. (2010) Radiation Resistance in Glioma Cells Determined by DNA Damage Repair Activity of Ape1/Ref-1. Journal of Radiation Research, 51, 393-404.

[14]   Xiong, G.S., Sun, H.L., Wu, S.M., et al. (2010) Small Interfering RNA against the Apurinic or Apyrimidinic Endonuclease Enhances the Sensitivity of Human Pancreatic Cancer Cells to Gemcitabine in Vitro. Journal of Digestive Diseases, 11, 224-230.

[15]   Chen, S., Xiong, G., Wu, S., et al. (2013) Downregulation of Apurinic/Apyrimidinic Endonuclease 1/Redox Factor-1 Enhances the Sensitivity of Human Pancreatic Cancer Cells to Radiotherapy in Vitro. Cancer Biotherapy and Radiopharmaceuticals, 28, 169-176. http://dx.doi.org/10.1089/cbr.2012.1266

[16]   Wang, D., Luo, M. and Kelley, M.R. (2004) Human Apurinic Endonuclease 1 (APE1) Expression and Prognostic Significance in Osteosarcoma: Enhanced Sensitivity of Osteosarcoma to DNA Damaging Agents Using Silencing RNA APE1 Expression Inhibition. Molecular Cancer Therapeutics, 3, 679-686.

[17]   Decker, S., Winkelmann, W., Nies, B., et al. (1999) Cytotoxic Effect of Methotrexate and Its Solvent on Osteosarcoma Cells in Vitro. The Journal of Bone & Joint Surgery (British Volume), 81, 545-551. http://dx.doi.org/10.1302/0301-620X.81B3.9167

[18]   Brambilla, D., Zamboni, S., Federici, C., et al. (2012) P-Glycoprotein Binds to Ezrin at Amino Acid Residues 149-242 in the FERM Domain and Plays a Key Role in the Multidrug Resistance of Human Osteosarcoma. International Journal of Cancer, 130, 2824-2834. http://dx.doi.org/10.1002/ijc.26285

[19]   Wilson III, D.M. and Seidman, M.M. (2010) A Novel Link to Base Excision Repair? Trends in Biochemical Sciences, 35, 247-252. http://dx.doi.org/10.1016/j.tibs.2010.01.003

[20]   Wang, D., Xiang, D.B., Yang, X.Q., et al. (2009) APE1 Overexpression Is Associated with Cisplatin Resistance in Non-Small Cell Lung Cancer and Targeted Inhibition of APE1 Enhances the Activity of Cisplatin in A549 Cells. Lung Cancer, 66, 298-304. http://dx.doi.org/10.1016/j.lungcan.2009.02.019

[21]   Kothandapani, A., Dangeti, V.S., Brown, A.R., et al. (2011) Novel Role of Base Excision Repair in Mediating Cisplatin Cytotoxicity. Journal of Biological Chemistry, 286, 14564-14574.

[22]   Couve-Privat, S., Mace, G., Rosselli, F., et al. (2007) Psoralen-Induced DNA Adducts Are Substrates for the Base Excision Repair Pathway in Human Cells. Nucleic Acids Research, 35, 5672-5682. http://dx.doi.org/10.1093/nar/gkm592

[23]   Allan, J.M., Engelward, B.P., Dreslin, A.J., et al. (1998) Mammalian 3-Methyladenine DNA Glycosylase Protects against the Toxicity and Clastogenicity of Certain Chemotherapeutic DNA Cross-Linking Agents. Cancer Research, 58, 3965-3973.

[24]   Borchers, A.H., Kennedy, K.A. and Straw, J.A. (1990) Inhibition of DNA Excision Repair by Methotrexate in Chinese Hamster Ovary Cells Following Exposure to Ultraviolet Irradiation or Ethylmethanesulfonate. Cancer Research, 50, 1786-1789.

[25]   Guerreiro, P.S., Fernandes, A.S., Costa, J.G., et al. (2013) Differential Effects of Methoxyamine on Doxorubicin Cytotoxicity and Genotoxicity in MDA-MB-231 Human Breast Cancer Cells. Mutation Research, 757, 140-147. http://dx.doi.org/10.1016/j.mrgentox.2013.08.003

[26]   Ozaki, T., Flege, S., Kevric, M., et al. (2003) Osteosarcoma of the Pelvis: Experience of the Cooperative Osteosarcoma Study Group. Journal of Clinical Oncology, 21, 334-341.

[27]   Kinsella, T.J. (2009) Coordination of DNA Mismatch Repair and Base Excision Repair Processing of Chemotherapy and Radiation Damage for Targeting Resistant Cancers. Clinical Cancer Research, 15, 1853-1859. http://dx.doi.org/10.1158/1078-0432.CCR-08-1307

[28]   Savvides, P., Xu, Y., Liu, L., et al. (2010) Pharmacokinetic Profile of the Base-Excision Repair Inhibitor Methoxyamine-HCl (TRC102; MX) Given as an One-Hour Intravenous Infusion with Temozolomide (TMZ) in the First-in-Human Phase I Clinical Trial. Journal of Clinical Oncology, 28, Article ID: e13662.