Supplementary Data contains Supplementary Table S1: Primer Sequences Supplementary Figure S1: Gene Layout on RealTime Ready custom 96 well panel Supplementary Figure S2: OCT1002 targets 22Rv1 and PC3 in hypoxic conditions Supplementary Figure S3: OCT1002 induces apoptosis in LNCAP-luc spheroids Supplementary Figure S4: Effect of bicalutamide and OCT1002 on tumor growth in 22Rv1 xenografts Supplementary Figure S5: Stereological analysis of microvessels in LNCaP tumors grown in window chambers Supplementary Figure S6: Effect of bicalutamide on oxygenation of 22Rv1 xenografts
Funding
Prostate Cancer UK research grant
Department of Employment and Learning, Northern Ireland
ARTICLE ABSTRACT
Purpose: To understand the role of hypoxia in prostate tumor progression and to evaluate the ability of the novel unidirectional hypoxia-activated prodrug OCT1002 to enhance the antitumor effect of bicalutamide.Experimental Design: The effect of OCT1002 on prostate cancer cells (LNCaP, 22Rv1, and PC3) was measured in normoxia and hypoxia in vitro. In vivo, tumor growth and lung metastases were measured in mice treated with bicalutamide, OCT1002, or a combination. Dorsal skin fold chambers were used to image tumor vasculature in vivo. Longitudinal gene expression changes in tumors were analyzed using PCR.Results: Reduction of OCT1002 to its active form (OCT1001) decreased prostate cancer cell viability. In LNCaP-luc spheroids, OCT1002 caused increased apoptosis and decreased clonogenicity. In vivo, treatment with OCT1002 alone, or with bicalutamide, showed significantly greater tumor growth control and reduced lung metastases compared with controls. Reestablishment of the tumor microvasculature following bicalutamide-induced vascular collapse is inhibited by OCT1002. Significantly, the upregulation of RUNX2 and its targets caused by bicalutamide alone was blocked by OCT1002.Conclusions: OCT1002 selectively targets hypoxic tumor cells and enhances the antitumor efficacy of bicalutamide. Furthermore, bicalutamide caused changes in gene expression, which indicated progression to a more malignant genotype; OCT1002 blocked these effects, emphasizing that more attention should be attached to understanding genetic changes that may occur during treatment. Early targeting of hypoxic cells with OCT1002 can provide a means of inhibiting prostate tumor growth and malignant progression. This is of importance for the design and refinement of existing androgen-deprivation regimens in the clinic. Clin Cancer Res; 23(7); 1797–808. ©2016 AACR.
