Nano-Targeted Delivery of Toremifene, an Estrogen Receptor-α Blocker in Prostate Cancer



Estrogen Receptor-α (ERα) expression is increased in prostate cancer and acts as an oncogene. We propose that blocking of estrogen hormone binding to ERα using the ERα blocker toremifene will reduce the tumorigenicity of prostate cancer, and nano-targeted delivery of toremifene will improve anticancer efficacy. We report the synthesis and use in an orthotopic mouse model of PLGA-PEG nanoparticles encapsulating toremifene and nanoparticles encapsulating toremifene that are also conjugated to anti-PSMA for targeted prostate tumor delivery.


Human prostate cancer cell line PC3M and a nude mouse model were used to test efficacy of nano-targeted and nano-encapsulated toremifene versus free toremifene on the growth and differentiation of tumor cells.


Treatment with free toremifene resulted in a significant reduction in growth of prostate tumor and proliferation, and its nano-targeting resulted in greater reduction of prostate tumor growth, greater toremifene tumor uptake, and enhanced tumor necrosis. Tumors from animals treated with nano-encapsulated toremifene conjugated with anti-PSMA showed about a 15-fold increase of toremifene compared to free toremifene.


Our data provide evidence that blocking ERα by toremifene and targeting prostate cancer tissues with anti-PSMA antibody on the nanoparticles’ surface repressed the tumorigenicity of prostate cancer cells in this mouse model.

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7



Estrogen receptor alpha


Estrogen receptor beta


High Grade Prostatic Intraepithelial Hyperplasia


3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide


Poly (ethylene glycol)


Poly (lactic-co-glycolic acid)


Prostate specific membrane antigen


Selective estrogen receptor modulator


  1. 1.

    American Cancer Society. Cancer Facts & Figures 2014. 2014 September 10. Available from:

  2. 2.

    Siegel R, Naishadham D, Jemal A. Cancer statistics, 2012. CA Cancer J Clin. 2012;62(1):10–29.

    PubMed  Article  Google Scholar 

  3. 3.

    Khadige M, Peiffert D, Supiot S. What is the level of evidence of new techniques in prostate cancer radiotherapy? Cancer Radiother. 2014;18(5–6):501–8.

    CAS  PubMed  Article  Google Scholar 

  4. 4.

    Fizazi K, Scher HI, Miller K, Basch E, Sternberg CN, Cella D, et al. Effect of enzalutamide on time to first skeletal-related event, pain, and quality of life in men with castration-resistant prostate cancer: results from the randomised, phase 3 AFFIRM trial. Lancet Oncol. 2014;15(10):1147–56.

    CAS  PubMed  Article  Google Scholar 

  5. 5.

    Stewart SB, Cheville JC, Sebo TJ, Frank I, Boorjian SA, Thompson RH, et al. Gleason grading after neoadjuvant hormonal therapy retains prognostic value for systemic progression following radical prostatectomy. Prostate Cancer Prostatic Dis. 2014;17(4):332–7.

    CAS  PubMed  Article  Google Scholar 

  6. 6.

    Ziehr DR, Chen MH, Zhang D, Braccioforte MH, Moran BJ, Mahal BA, et al. Association of androgen deprivation therapy with excess cardiac-specific mortality in men with prostate cancer. BJU Int. 2014. doi:10.1111/bju.12905.

    PubMed  Google Scholar 

  7. 7.

    Lee HY, Wu WJ, Huang CH, Chou YH, Huang CN, Lee YC, et al. Clinical predictor of survival following docetaxel-based chemotherapy. Oncol Lett. 2014;8(4):1788–92.

    PubMed Central  PubMed  Google Scholar 

  8. 8.

    Gordon RR, Wu M, Huang CY, Harris WP, Sim HG, Lucas JM, et al. Chemotherapy-induced monoamine oxidase expression in prostate carcinoma functions as a cytoprotective resistance enzyme and associates with clinical outcomes. PLoS One. 2014;9(9):e104271.

    PubMed Central  PubMed  Article  Google Scholar 

  9. 9.

    Shigeta K, Kosaka T, Yazawa S, Yasumizu Y, Mizuno R, Nagata H, et al. Predictive factors for severe and febrile neutropenia during docetaxel chemotherapy for castration-resistant prostate cancer. Int J Clin Oncol. 2014. doi:10.1007/s10147-014-0746-7.

    Google Scholar 

  10. 10.

    LaRocque J, Bharali DJ, Mousa SA. Cancer detection and treatment: the role of nanomedicines. Mol Biotechnol. 2009;42(3):358–66.

    CAS  PubMed  Article  Google Scholar 

  11. 11.

    Raghow S, Hooshdaran MZ, Katiyar S, Steiner MS. Toremifene prevents prostate cancer in the transgenic adenocarcinoma of mouse prostate model. Cancer Res. 2002;62(5):1370–6.

    CAS  PubMed  Google Scholar 

  12. 12.

    Mousa SA, Bharali DJ. Nanotechnology-based detection and targeted therapy in cancer: nano-bio paradigms and applications. Cancers. 2011;3(3):2888–903.

    CAS  PubMed Central  PubMed  Article  Google Scholar 

  13. 13.

    Holzmann C, Kilch T, Kappel S, Armbruster A, Jung V, Stockle M, et al. ICRAC controls the rapid androgen response in human primary prostate epithelial cells and is altered in prostate cancer. Oncotarget. 2013;4(11):2096–107.

    PubMed Central  PubMed  Google Scholar 

  14. 14.

    Sokoloff RL, Norton KC, Gasior CL, Marker KM, Grauer LS. A dual-monoclonal sandwich assay for prostate-specific membrane antigen: levels in tissues, seminal fluid and urine. Prostate. 2000;43(2):150–7.

    CAS  PubMed  Article  Google Scholar 

  15. 15.

    Ristau BT, O'Keefe DS, Bacich DJ. The prostate-specific membrane antigen: lessons and current clinical implications from 20 years of research. Urol Oncol. 2013;32(3):272–9.

    PubMed Central  PubMed  Article  Google Scholar 

  16. 16.

    Troyer JK, Beckett ML, Wright Jr GL. Detection and characterization of the prostate-specific membrane antigen (PSMA) in tissue extracts and body fluids. Int J Cancer. 1995;62(5):552–8.

    CAS  PubMed  Article  Google Scholar 

  17. 17.

    Cao KY, Xu L, Zhang DM, Zhang XM, Zhang T, He X, et al. New alternatively spliced variant of prostate-specific membrane antigen PSM-E suppresses the proliferation, migration and invasiveness of prostate cancer cells. Int J Oncol. 2012;40(6):1977–85.

    CAS  PubMed  Google Scholar 

  18. 18.

    Su SL, Huang IP, Fair WR, Powell CT, Heston WD. Alternatively spliced variants of prostate-specific membrane antigen RNA: ratio of expression as a potential measurement of progression. Cancer Res. 1995;55(7):1441–3.

    CAS  PubMed  Google Scholar 

  19. 19.

    Akhtar NH, Pail O, Saran A, Tyrell L, Tagawa ST. Prostate-specific membrane antigen-based therapeutics. Adv Urol. 2012;2012:Article ID 973820.

  20. 20.

    Chang SS. Overview of prostate-specific membrane antigen. Rev Urol. 2004;6 Suppl 10:S13–8.

    PubMed Central  PubMed  Article  Google Scholar 

  21. 21.

    Bonkhoff H, Berges R. The evolving role of oestrogens and their receptors in the development and progression of prostate cancer. Eur Urol. 2009;55(3):533–42.

    CAS  PubMed  Article  Google Scholar 

  22. 22.

    Price D, Stein B, Sieber P, Tutrone R, Bailen J, Goluboff E, et al. Toremifene for the prevention of prostate cancer in men with high grade prostatic intraepithelial neoplasia: results of a double-blind, placebo controlled, phase IIB clinical trial. J Urol. 2006;176(3):965–70. discussion 970–961.

    CAS  PubMed  Article  Google Scholar 

  23. 23.

    Matthews J, Gustafsson JA. Estrogen signaling: a subtle balance between ER alpha and ER beta. Mol Interv. 2003;3(5):281–92.

    CAS  PubMed  Article  Google Scholar 

  24. 24.

    Bharali DJ, Yalcin M, Davis PJ, Mousa SA. Tetraiodothyroacetic acid-conjugated PLGA nanoparticles: a nanomedicine approach to treat drug-resistant breast cancer. Nanomedicine. 2013;8(12):1943–54.

    CAS  PubMed  Article  Google Scholar 

  25. 25.

    Cho HS, Dong Z, Pauletti GM, Zhang J, Xu H, Gu H, et al. Fluorescent, superparamagnetic nanospheres for drug storage, targeting, and imaging: a multifunctional nanocarrier system for cancer diagnosis and treatment. ACS Nano. 2010;4(9):5398–404.

    CAS  PubMed  Article  Google Scholar 

  26. 26.

    Graf N, Bielenberg DR, Kolishetti N, Muus C, Banyard J, Farokhzad OC, et al. alpha(V)beta(3) integrin-targeted PLGA-PEG nanoparticles for enhanced anti-tumor efficacy of a Pt(IV) prodrug. ACS Nano. 2012;6(5):4530–9.

    CAS  PubMed Central  PubMed  Article  Google Scholar 

  27. 27.

    Bansal G, Maddhesia PK, Bansal Y. MS2/TOF and LC-MS/TOF studies on toremifene to characterize its forced degradation products. Analyst. 2011;136(24):5218–28.

    CAS  PubMed  Article  Google Scholar 

  28. 28.

    Mazzarino M, Fiacco I, de la Torre X, Botre F. A mass spectrometric approach for the study of the metabolism of clomiphene, tamoxifen and toremifene by liquid chromatography time-of-flight spectroscopy. Eur J Mass Spectrom. 2008;14(3):171–80.

    CAS  Article  Google Scholar 

  29. 29.

    Sumantran VN. Cellular chemosensitivity assays: an overview. Methods Mol Biol. 2011;731:219–36.

    CAS  PubMed  Article  Google Scholar 

  30. 30.

    Gao X, Yang L, Petros JA, Marshall FF, Simons JW, Nie S. In vivo molecular and cellular imaging with quantum dots. Curr Opin Biotechnol. 2005;16(1):63–72.

    CAS  PubMed  Article  Google Scholar 

  31. 31.

    Kim IY, Kim BC, Seong DH, Lee DK, Seo JM, Hong YJ, et al. Raloxifene, a mixed estrogen agonist/antagonist, induces apoptosis in androgen-independent human prostate cancer cell lines. Cancer Res. 2002;62(18):5365–9.

    CAS  PubMed  Google Scholar 

  32. 32.

    Lopes AD, Davis WL, Rosenstraus MJ, Uveges AJ, Gilman SC. Immunohistochemical and pharmacokinetic characterization of the site-specific immunoconjugate CYT-356 derived from antiprostate monoclonal antibody 7E11-C5. Cancer Res. 1990;50(19):6423–9.

    CAS  PubMed  Google Scholar 

Download references


We would like to express our thanks to Dr. Murat Yalcin (Uludag University, Turkey) and Dr. Hasan Mukhtar (University of Wisconsin, Madison, WI) for their suggestions, and Dr. Kelly Keating (ACPHS) for excellent editing. The authors report no conflicts of interest.

Author information



Corresponding author

Correspondence to Shaker A. Mousa.

Additional information

Waseem Hariri and Thangirala Sudha contributed equally to this work.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Hariri, W., Sudha, T., Bharali, D.J. et al. Nano-Targeted Delivery of Toremifene, an Estrogen Receptor-α Blocker in Prostate Cancer. Pharm Res 32, 2764–2774 (2015).

Download citation


  • anti-PSMA antibody
  • estrogen receptor-α blocker
  • nanomedicine
  • nano-targeted therapy
  • prostate cancer