Abstract 693: Oncogenic and osteolytic function of histone demethylase NO66 in castration resistant prostate cancer
Authors: Rozita Bagheri-Yarmand, Nora Navone, Xinhai Wan, Christopher Logothetis, Johnny Huard, Krishna Sinha
Journal: Cancer Research (2016)

Abstract Androgen ablation by pharmacological use or castration is a standard therapy for treating prostate cancer (PCa), however, at the later stage PCa becomes castration-resistant and is metastasized primarily to bones. Epigenetic changes that cause dysregulated gene expression during progression and metastasis of androgen-independent prostate cancer are not clearly understood. We previously reported that the jumonji C domain-containing NO66 is a histone demethylase specific for H3K4me3 and H3K36me3, which negatively regulates osteoblast differentiation and bone formation. By analyzing a multi-cancer tissue microarray, the serendipitous observation was made that NO66 is overexpressed in a variety of cancers. Our objective was to examine NO66's role in the pathogenesis of prostate cancer and bone metastasis. Our findings indicate that NO66 knockdown resulted in significant decreases in the proliferation and invasiveness of prostate cancer cells (PC3 and DU145) while overexpressing NO66 promoted their proliferation and invasion. Furthermore, NO66 depletion resulted in a two- to three fold decrease in colony formation and anchorage-independent growth of PCa cells suggesting an oncogenic function of NO66. RNAseq analysis comparing between control and NO66-depleted DU-145 cells revealed a repertoire of differentially expressed genes. NO66 up-regulates genes with proliferative activity such as chemokine CXCL5, growth factor IGFBP5, IL6, WNT and MAPK4 pathway, which are known to drive PCa proliferation. Furthermore, ChIP sequencing for NO66 and H3K9AC in NO66-overexpressing PC3 cells revealed that interaction sites of NO66 overlap with peaks of H3K9AC in majority of the genes. These data clearly indicate that NO66 activates a cohort of genes which are involved in tumor progression and metastasis. Strikingly, implanting NO66-overexpressing prostate cancer cells into the femur of SCID male mice caused massive femoral bone loss after three weeks, which suggests that NO66 causes osteolytic bone lesions similar to the clinico-pathological features of advanced PCa. Finally, analysis of tumor xenografts derived from patients by immunohistochemistry showed high expression of NO66 in high grade advanced PCa compared to low grade and hyperplasia suggesting that NO66 may be used as a biomarker to distinguish aggressive prostate cancer from indolent stage. Our data suggest that NO66 plays an important role in cell proliferation, cell invasion and bone metastasis of prostate cancer. Citation Format: Rozita Bagheri-Yarmand, Nora Navone, Xinhai Wan, Christopher Logothetis, Johnny Huard, Krishna Sinha. Oncogenic and osteolytic function of histone demethylase NO66 in castration resistant prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 693.