D. Professor, . Van-papendorp-for-general-support, C. Hall, and . Van-der-merwe, Laboratory for Microscopy and Microanalysis, University of Pretoria (UP)), A Stander, D Crafford and S Marais (Department of Physiology, UP) for technical assistance, Ms B English

S. Dr and . Olorunjo, Funding of this research is gratefully acknowledged from the following: The Cancer Association of South Africa (CANCA) (AOS201), the Medical Research Council, MRC) for statistics consultationMRC) (AOS536), the National Research Foundation (NRF) (AOT060) The Research Committee of the University of Pretoria (RESCOM) (AOR984), South African Medical Association (SAMA) and the Research Development Programme (UP) (AOV8410)

D. Matei, J. Schilder, G. Sutton, S. Perkins, T. Breen et al., Activity of 2 methoxyestradiol (Panzem?? NCD) in advanced, platinum-resistant ovarian cancer and primary peritoneal carcinomatosis: A Hoosier Oncology Group trial, Gynecologic Oncology, vol.115, issue.1, pp.90-96, 2009.
DOI : 10.1016/j.ygyno.2009.05.042

S. Mooberry, Mechanism of action of 2-methoxyestradiol: new developments. Drug Resist Update, pp.355-361, 2003.

A. Tevaarwerk, K. Holen, D. Alberti, C. Sidor, J. Arnott et al., Phase I Trial of 2-Methoxyestradiol NanoCrystal Dispersion in Advanced Solid Malignancies, Clinical Cancer Research, vol.15, issue.4, pp.1460-1465, 2009.
DOI : 10.1158/1078-0432.CCR-08-1599

R. Dubey and E. Jackson, Potential vascular actions of 2-methoxyestradiol, Trends in Endocrinology & Metabolism, vol.20, issue.8, pp.374-379, 2009.
DOI : 10.1016/j.tem.2009.04.007

S. Kato, A. Sadarangani, S. Lange, A. Delpiano, M. Vargas et al., 2-Methoxyestradiol Mediates Apoptosis Through Caspase-Dependent and Independent Mechanisms in Ovarian Cancer Cells But Not in Normal Counterparts, Reproductive Sciences, vol.15, issue.9, pp.878-894, 2008.
DOI : 10.1177/1933719108324171

B. Stander, S. Marais, C. Vorster, and A. Joubert, In vitro effects of 2-methoxyestradiol on morphology, cell cycle progression, cell death and gene expression changes in the tumorigenic MCF-7 breast epithelial cell line, The Journal of Steroid Biochemistry and Molecular Biology, vol.119, issue.3-5, pp.3-5149, 2010.
DOI : 10.1016/j.jsbmb.2010.02.019

G. Amorino, M. Freeman, and H. Choy, by the Estrogen Metabolite 2-Methoxyestradiol, Radiation Research, vol.153, issue.4, pp.384-391, 2000.
DOI : 10.1667/0033-7587(2000)153[0384:EOREIV]2.0.CO;2

G. Han, Z. Liu, K. Shimoi, and B. Zhu, Synergism between the anticancer actions of 2-methoxyestradiol and microtubule-disrupting agents in human breast cancer, Cancer Res, vol.65, issue.2, pp.387-393, 2005.

C. Van-zijl, M. Lottering, F. Steffens, and A. Joubert, effects of 2???methoxyestradiol on MCF???12A and MCF???7 cell growth, morphology and mitotic spindle formation, Cell Biochemistry and Function, vol.58, issue.5, pp.632-642, 2008.
DOI : 10.1002/cbf.1489

T. Fotsis, Y. Zhang, M. Pepper, H. Adlercreutz, R. Montesano et al., The endogenous oestrogen metabolite 2-methoxyoestradiol inhibits angiogenesis and suppresses tumour growth, Nature, vol.189, issue.6468, pp.237-239, 1994.
DOI : 10.1038/368237a0

S. Newman, C. Ireson, H. Tutill, J. Day, M. Parsons et al., The Role of 17??-Hydroxysteroid Dehydrogenases in Modulating the Activity of 2-Methoxyestradiol in Breast Cancer Cells, Cancer Research, vol.66, issue.1, pp.324-330, 2006.
DOI : 10.1158/0008-5472.CAN-05-2391

C. Sweeney, G. Liu, C. Yiannoutsos, J. Kolesar, D. Horvath et al., A Phase II Multicenter, Randomized, Double-Blind, Safety Trial Assessing the Pharmacokinetics, Pharmacodynamics, and Efficacy of Oral 2-Methoxyestradiol Capsules in Hormone-Refractory Prostate Cancer, Clinical Cancer Research, vol.11, issue.18, pp.116625-6633, 2005.
DOI : 10.1158/1078-0432.CCR-05-0440

Y. Tsuchiya, M. Nakajima, and T. Yokoi, Cytochrome P450-mediated metabolism of estrogens and its regulation in human, Cancer Letters, vol.227, issue.2, pp.115-124, 2005.
DOI : 10.1016/j.canlet.2004.10.007

B. Du, Y. Li, X. Li, A. Chen, C. Zhang et al., Preparation, characterization and in vivo evaluation of 2-methoxyestradiol-loaded liposomes, International Journal of Pharmaceutics, vol.384, issue.1-2, pp.140-147, 2010.
DOI : 10.1016/j.ijpharm.2009.09.045

M. Visagie and A. Joubert, In vitro effects of 2-methoxyestradiol-bis-sulphamate on reactive oxygen species and possible apoptosis induction in a breast adenocarcinoma cell line, Cancer Cell International, vol.11, issue.1, p.43, 2011.
DOI : 10.1074/jbc.M302559200

E. Pasquier, S. Sinnappan, M. Munoz, and M. Kavallaris, ENMD-1198, a New Analogue of 2-Methoxyestradiol, Displays Both Antiangiogenic and Vascular-Disrupting Properties, Molecular Cancer Therapeutics, vol.9, issue.5, pp.1408-1418
DOI : 10.1158/1535-7163.MCT-09-0894

X. Stander, B. Stander, and A. Joubert, In vitro effects of an in silico-modelled 17??-estradiol derivative in combination with dichloroacetic acid on MCF-7 and MCF-12A cells, Cell Proliferation, vol.36, issue.Suppl. 4, pp.44567-581, 2011.
DOI : 10.1111/j.1365-2184.2011.00789.x

S. Marais, T. Mqoco, A. Stander, D. Van-papendorp, and A. Joubert, The in vitro effects of a sulphamoylated derivative of 2-methoxyestradiol on cell number, morphology and alpha-Tubulin disruption in cervical adenocarcinoma (HeLa) cells, Biomed Res, vol.2012, issue.233, pp.357-362

T. Tinley, R. Leal, D. Randall-hlubek, J. Cessac, L. Wilkens et al., Novel 2-methoxyestradiol analogues with antitumor activity, Cancer Res, vol.63, issue.7, pp.1538-1549, 2003.

M. Cushman, H. He, J. Katzenellenbogen, C. Lin, and E. Hamel, Synthesis, anti-Tubulin and anti-mitotic activity, and cytotoxicity of analogs of 2-methoxyestradiol, an endogenous mammalian metabolite of Estradiol that inhibits Tubulin polymerization by binding to the colchicine binding site, J Med Chem, issue.12, pp.382041-2049, 1995.

M. Leese, S. Newman, A. Purohit, M. Reed, and B. Potter, 2-Alkylsulfanyl Estrogen Derivatives: Synthesis of a Novel Class of Multi-Targeted Antitumor Agents., ChemInform, vol.14, issue.39, pp.143135-3138, 2004.
DOI : 10.1002/chin.200439166

T. Lavallee, P. Burke, G. Swartz, E. Hamel, G. Agoston et al., Significant antitumor activity in vivo following treatment with the microtubule agent ENMD-1198, Molecular Cancer Therapeutics, vol.7, issue.6, pp.1472-1482, 2008.
DOI : 10.1158/1535-7163.MCT-08-0107

A. Edsall, A. Mohanakrishnan, D. Yang, P. Fanwick, E. Hamel et al., Effects of Altering the Electronics of 2-Methoxyestradiol on Cell Proliferation, on Cytotoxicity in Human Cancer Cell Cultures, and on Tubulin Polymerization, Journal of Medicinal Chemistry, vol.47, issue.21, pp.475126-5139, 2004.
DOI : 10.1021/jm049647a

W. Elger, S. Schwarz, A. Hedden, G. Reddersen, and B. Schneider, Sulfamates of various estrogens are pro-drugs with increased systemic and reduced hepatic estrogenicity at oral application, J Steroid Biochem Mol Biol, vol.55, pp.3-4395, 1995.

Y. Ho, A. Purohit, N. Vicker, S. Newman, J. Robinson et al., Inhibition of carbonic anhydrase II by steroidal and non-steroidal sulphamates, Biochemical and Biophysical Research Communications, vol.305, issue.4, pp.909-914, 2003.
DOI : 10.1016/S0006-291X(03)00865-9

S. Pastorekova, P. Ratcliffe, and J. Pastorek, Molecular mechanisms of carbonic anhydrase IX-mediated pH regulation under hypoxia, BJU International, vol.13, issue.s4, pp.8-15, 2008.
DOI : 10.1038/nature04871

J. Chiche, K. Ilc, J. Laferrière, E. Trottier, F. Dayan et al., Hypoxia-Inducible Carbonic Anhydrase IX and XII Promote Tumor Cell Growth by Counteracting Acidosis through the Regulation of the Intracellular pH, Cancer Research, vol.69, issue.1, pp.358-368, 2009.
DOI : 10.1158/0008-5472.CAN-08-2470

URL : https://hal.archives-ouvertes.fr/hal-00358780

M. Stubbs, P. Mcsheehy, J. Griffiths, and C. Bashford, Causes and consequences of tumour acidity and implications for treatment, Molecular Medicine Today, vol.6, issue.1, pp.15-19, 2000.
DOI : 10.1016/S1357-4310(99)01615-9

W. Elger, A. Barth, A. Hedden, G. Reddersen, P. Ritter et al., Estrogen sulfamates: a new approach to oral estrogen therapy, Reproduction, Fertility and Development, vol.13, issue.4, pp.297-305, 2001.
DOI : 10.1071/RD01029

C. Vorster and A. Joubert, In vitro effects of 2-methoxyestradiol-bis-sulphamate on cell growth, morphology and cell cycle dynamics in the MCF-7 breast adenocarcinoma cell line, Biocell, vol.34, issue.2, pp.71-79, 2010.

C. Ireson, S. Chander, A. Purohit, S. Perera, S. Newman et al., Pharmacokinetics and efficacy of 2-methoxyoestradiol and 2-methoxyoestradiol-bis-sulphamate in vivo in rodents, British Journal of Cancer, vol.90, issue.4, pp.932-937, 2004.
DOI : 10.1038/sj.bjc.6601591

A. Stander, F. Joubert, and A. Joubert, Docking, Synthesis, and in vitro Evaluation of Antimitotic Estrone Analogs, Chemical Biology & Drug Design, vol.27, issue.Suppl. 4, pp.173-181, 2011.
DOI : 10.1111/j.1747-0285.2010.01064.x

T. Miyazaki and S. Arai, Two Distinct Controls of Mitotic Cdk1/Cyclin B1 Activity Requisite for Cell Growth Prior to Cell Division, Cell Cycle, vol.6, issue.12, pp.1418-1424, 2007.
DOI : 10.4161/cc.6.12.4409

E. Boucrot and T. Kirchhausen, Mammalian Cells Change Volume during Mitosis, PLoS ONE, vol.112, issue.14, p.1477, 2008.
DOI : 10.1371/journal.pone.0001477.g002

E. Laane, K. Tamm, E. Buentke, K. Ito, P. Khahariza et al., Cell death induced by Dexamethasone in lymphoid leukemia is mediated through initiation of autophagy, Cell Death Differ, issue.7, pp.161018-1029, 2009.

V. Thaver, M. Lottering, D. Van-papendorp, and A. Joubert, effects of 2-methoxyestradiol on cell numbers, morphology, cell cycle progression, and apoptosis induction in oesophageal carcinoma cells, Cell Biochemistry and Function, vol.23, issue.4, pp.205-210, 2009.
DOI : 10.1002/cbf.1557

L. Li, S. Bu, T. Backstrom, M. Landstrom, U. Ulmsten et al., Induction of apoptosis and G2/M arrest by 2-methoxyestradiol in human cervical cancer HeLaS3 cells, Anticancer Res, issue.2B, pp.24873-880, 2004.

I. Androic, A. Kramer, R. Yan, F. Rodel, R. Gatje et al., Targeting cyclin B1 inhibits proliferation and sensitizes breast cancer cells to taxol, BMC Cancer, vol.6, issue.1, p.391, 2008.
DOI : 10.4161/cc.6.11.4297

D. Matson and P. Stukenberg, Spindle Poisons and Cell Fate: A Tale of Two Pathways, Molecular Interventions, vol.11, issue.2, pp.141-150, 2011.
DOI : 10.1124/mi.11.2.12

I. Wertz, S. Kusam, C. Lam, T. Okamoto, W. Sandoval et al., Sensitivity to anti-Tubulin chemotherapeutics is regulated by MCL1 and FBW7, Nature, issue.7336, pp.471110-114, 2011.

S. Newman, P. Foster, C. Stengel, J. Day, Y. Ho et al., STX140 Is Efficacious In vitro and In vivo in Taxane-Resistant Breast Carcinoma Cells, Clinical Cancer Research, vol.14, issue.2, pp.597-606, 2008.
DOI : 10.1158/1078-0432.CCR-07-1717

H. Huang, J. Shi, J. Orth, and T. Mitchison, Evidence that Mitotic Exit Is a Better Cancer Therapeutic Target Than Spindle Assembly, Cancer Cell, vol.16, issue.4, pp.347-358, 2009.
DOI : 10.1016/j.ccr.2009.08.020

T. Lavallee, X. Zhan, M. Johnson, C. Herbstritt, G. Swartz et al., 2-methoxyestradiol up-regulates death receptor 5 and induces apoptosis through activation of the extrinsic pathway, Cancer Res, vol.63, issue.2, pp.468-475, 2003.

M. Ola, M. Nawaz, and H. Ahsan, Role of Bcl-2 family proteins and caspases in the regulation of apoptosis, Molecular and Cellular Biochemistry, vol.277, issue.2, pp.41-58, 2011.
DOI : 10.1007/s11010-010-0709-x

M. Kadowaki, M. Karim, A. Carpi, and G. Miotto, Nutrient control of macro-autophagy in mammalian cells, Mol Aspects Med, vol.27, pp.5-6426, 2006.

M. Djavaheri-mergny, M. Maiuri, and G. Kroemer, Cross talk between apoptosis and autophagy by caspase-mediated cleavage of Beclin 1, Oncogene, vol.11, issue.12, pp.1717-1719, 2010.
DOI : 10.1038/ncb1482

M. Maiuri, E. Zalckvar, A. Kimchi, and G. Kroemer, Self-eating and self-killing: crosstalk between autophagy and apoptosis, Nature Reviews Molecular Cell Biology, vol.6, issue.9, pp.741-752, 2007.
DOI : 10.1038/nrm2239

Z. Xie and D. Klionsky, Autophagosome formation: core machinery and adaptations, Nature Cell Biology, vol.2, issue.10, pp.1102-1109
DOI : 10.1016/j.bbrc.2005.10.163

E. Wirawan, V. Walle, L. Kersse, K. Cornelis, S. Claerhout et al., Caspase-mediated cleavage of Beclin-1 inactivates Beclin-1-induced autophagy and enhances apoptosis by promoting the release of proapoptotic factors from mitochondria, Cell Death and Disease, vol.251, issue.1, p.18, 2010.
DOI : 10.1038/cddis.2009.16

D. Cho, Y. Jo, J. Hwang, Y. Lee, S. Roh et al., Caspase-mediated cleavage of ATG6/Beclin-1 links apoptosis to autophagy in HeLa cells, Cancer Letters, vol.274, issue.1, pp.95-100, 2009.
DOI : 10.1016/j.canlet.2008.09.004

S. Luo and D. Rubinsztein, Apoptosis blocks Beclin 1-dependent autophagosome synthesis: an effect rescued by Bcl-xL, Cell Death and Differentiation, vol.3, issue.2, pp.268-277, 2010.
DOI : 10.1016/j.canlet.2008.09.004

V. Betin and J. Lane, Caspase cleavage of Atg4D stimulates GABARAP-L1 processing and triggers mitochondrial targeting and apoptosis, Journal of Cell Science, vol.122, issue.14, pp.2554-2566, 2009.
DOI : 10.1242/jcs.046250