Abstract B14: Characterization of an in vivo generated subpopulation of human LNCaP prostate cancer cells as an improved testosterone-dependent subcutaneous as well as orthotopic in vivo mouse xenograft model for compound testing.

Abstract

Abstract Prostate cancer is one of the most frequently diagnosed cancer entities in men. It can be estimated that in 80% of all men reaching the age of 80 years prostate tumors are present. Since a depletion of testosterone in prostate cancer therapies is often performed, androgen-dependent and -independent prostate carcinoma cell lines have been widely used to establish mouse in vivo xenograft models in order to identify novel drugs helping to eliminate prostate tumors. A commercially available LNCaP cell line was shown to be androgen-dependent since addition of synthetic androgens to androgen-free culture medium was able to restore proper cell proliferation in cell culture. However, when implanted in SCID mice in order to establish a xenograft model, the take rate turned out to be very low and tumor growth was highly heterogeneously. Therefore, we resected and recultivated one of the few well-growing tumors and reimplanted the arising subpopulation subcutaneously in mice. After performing two rounds of this “subpopulationing” procedure we could generate a new cell line, LNCaP-(Z2), which was able to form tumors in mice with a take rate of nearly 100%, but still shows heterogenous tumor growth similar to other subcutaneously implanted prostate cancer cells (e.g. PC-3). In order to demonstrate an androgen dependency of our new LNCaP subpopulation model in vivo we used castrated mice and implanted them subcutaneously in the absence or presence of also subcutaneously inoculated testosterone pellets. For comparison PC-3 prostate cancer cells were also implanted subcutaeously in the presence or absence of testosterone. Whereas no influence of testosterone was detectable on the growth behavior of subcutaneous PC-3 xenograft tumors, the development of the LNCaP-(Z2) xenografts was strictly dependent on testosterone release. We then implanted fire fly luciferase expressing LNCaP-(Z2)-luc cells orthotopically into the prostate of castrated male SCID beige mice with or without testosterone supplementation to show testosterone-dependency. Finally, treatment of Bicalutamide, a typical member of the class of anti-androgens, which is frequently used in the treatment of prostate cancer, led to significant inhibition of tumor growth using our improved subpopulation LNCaP-(Z2) in vivo model. Bicalutmid and Flutamid, another anti-androgen agent, were used for treatment in the orthopical in vivo model. Both compounds showed a noticeable anti-tumoral effect at necropsy. Thus, we could demonstrate the model's potency as a testosterone-dependent in vivo tool suitable for screening and development of novel anti-prostate cancer drugs. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B14. Citation Format: Andreas Lingnau, Sandra Moor, Steffen Hoffmann, Cynthia Schaefer-Obodozie, Ulrike Leisegang, Klotzbuecher Andrea, Schaechtele Christoph. Characterization of an in vivo generated subpopulation of human LNCaP prostate cancer cells as an improved testosterone-dependent subcutaneous as well as orthotopic in vivo mouse xenograft model for compound testing. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B14.