Inhibition of EZH2 induces NK cell-mediated differentiation and death in muscle-invasive bladder cancer

Lysine-specific demethylase 6A (KDM6A) and members of the Switch/Sucrose Non-Fermentable (SWI/SNF) family are known to counteract the activity of Enhancer of Zeste Homolog 2 (EZH2), which is often overexpressed and is associated with poor prognosis in muscle-invasive bladder cancer. Here we provide evidence that alterations in chromatin modifying enzymes, including KDM6A and members of the SWI/SNF complex, are frequent in muscle-invasive bladder cancer. We exploit the loss of function mutations in KDM6A and SWI/SNF complex to make bladder cancer cells susceptible to EZH2-based epigenetic therapy that activates an immune response to drive tumor cell differentiation and death. We reveal a novel mechanism of action of EZH2 inhibition, alone and in combination with cisplatin, which induces immune signaling with the largest changes observed in interferon gamma (IFN-γ). This upregulation is a result of activated natural killer (NK) signaling as demonstrated by the increase in NK cell-associated genes MIP-1α, ICAM1, ICAM2, and CD86 in xenografts treated with EZH2 inhibitors. Conversely, EZH2 inhibition results in decreased expression of pluripotency markers, ALDH2 and CK5, and increased cell death. Our results reveal a novel sensitivity of muscle-invasive bladder cancer cells with KMD6A and SWI/SNF mutations to EZH2 inhibition alone and in combination with cisplatin. This sensitivity is mediated through increased NK cell-related signaling resulting in tumor cell differentiation and cell death.Fil: Ramakrishnan, Swathi. Roswell Park Comprehensive Cancer Center; Estados UnidosFil: Granger, Victoria. Roswell Park Comprehensive Cancer Center; Estados UnidosFil: Rak, Monica. Jagiellonian University; PoloniaFil: Hu, Qiang. Roswell Park Comprehensive Cancer Center; Estados UnidosFil: Attwood, Kristopher. Roswell Park Comprehensive Cancer Center; Estados UnidosFil: Aquila, Lanni. Roswell Park Comprehensive Cancer Center; Estados UnidosFil: Krishnan, Nithya. Roswell Park Comprehensive Cancer Center; Estados UnidosFil: Osiecki, Rafal. Medical University Of Warsaw; PoloniaFil: Azabdaftari, Gissou. Roswell Park Comprehensive Cancer Center; Estados UnidosFil: Guru, Khurshid. Roswell Park Comprehensive Cancer Center; Estados UnidosFil: Chatta, Gurkamal. Roswell Park Comprehensive Cancer Center; Estados UnidosFil: Gueron, Geraldine. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: McNally, Lacey. Wake Forest Comprehensive Cancer Center; Estados UnidosFil: Ohm, Joyce. Roswell Park Comprehensive Cancer Center; Estados UnidosFil: Wang, Jianmin. Roswell Park Comprehensive Cancer Center; Estados UnidosFil: Woloszynska-Read, Anna. Roswell Park Comprehensive Cancer Center; Estados Unido

Inhibition of Dihydrotestosterone Synthesis in Prostate Cancer by Combined Frontdoor and Backdoor Pathway Blockade

Androgen deprivation therapy (ADT) is palliative and prostate cancer (CaP) recurs as lethal castration-recurrent/resistant CaP (CRPC). One mechanism that provides CaP resistance to ADT is primary backdoor androgen metabolism, which uses up to four 3α-oxidoreductases to convert 5α-androstane-3α,17β-diol (DIOL) to dihydrotestosterone (DHT). The goal was to determine whether inhibition of 3α-oxidoreductase activity decreased conversion of DIOL to DHT. Protein sequence analysis showed that the four 3α-oxidoreductases have identical catalytic amino acid residues. Mass spectrometry data showed combined treatment using catalytically inactive 3α-oxidoreductase mutants and the 5α-reductase inhibitor, dutasteride, decreased DHT levels in CaP cells better than dutasteride alone. Combined blockade of frontdoor and backdoor pathways of DHT synthesis provides a therapeutic strategy to inhibit CRPC development and growth

Intake of dietary antioxidants is inversely associated with biomarkers of oxidative stress among men with prostate cancer

Abstract Prostate cancer is the most common non-cutaneous cancer and the second leading cause of cancer-related mortality among men in the USA. Growing evidence suggests that oxidative stress is involved in the development and progression of prostate cancer. In this study, the association between antioxidants from diet and supplements and biomarkers of oxidative stress in blood ( n 278), urine ( n 298) and prostate tissue ( n 55) were determined among men from the North Carolina-Louisiana Prostate Cancer Project. The association between antioxidant intake and oxidative stress biomarkers in blood and urine was determined using linear regression, adjusting for age, race, prostate cancer aggressiveness and smoking status. Greater antioxidant intake was found to be associated with lower urinary 8-isoprostane concentrations, with a 10 % increase in antioxidant intake corresponding to an unadjusted 1·1 % decrease in urinary 8-isoprostane levels (95 % CI −1·7, −0·3 %; P value<0·01) and an adjusted 0·6 % decrease (95 % CI −1·4, 0·2 %; P value=0·16). In benign prostate tissue, thioredoxin 1 was inversely associated with antioxidant intake ( P =0·02). No significant associations were found for other blood or urinary biomarkers or for malignant prostate tissue. These results indicate that antioxidant intake may be associated with less oxidative stress among men diagnosed with prostate cancer

Serum Glutamate Levels Correlate with Gleason Score and Glutamate Blockade Decreases Proliferation, Migration, and Invasion and Induces Apoptosis in Prostate Cancer Cells

During glutaminolysis, glutamine is catabolized to glutamate and incorporated into citric acid cycle and lipogenesis. Serum glutamate levels were measured in patients with primary prostate cancer (PCa) or metastatic castrate-resistant PCa (mCRPCa) to establish clinical relevance. The effect of glutamate-deprivation or blockade by metabotropic glutamate receptor 1 (GRM1)-antagonists was investigated on PCa cells’ growth, migration, and invasion to establish biological relevance

Generation of a syngeneic orthotopic transplant model of prostate cancer metastasis. Oncoscience

ABSTRACT Progression to metastatic disease is the primary cause of mortality in men with prostate cancer (PCa). Mouse models which progress with spontaneous metastasis are limited. Such models would allow for extensive studies of molecular mechanisms of metastasis, and more definite pre-clinical therapy trials. Orthotopic murine models have been described; however a limiting biology of these models is their lack of an intact immune system. Within, we describe the development of an androgen sensitive and castrate resistant tractable orthotopic murine syngeneic (immune competent) model of prostate cancer. Both models develop primary tumors which spontaneously progress to metastatic disease in lymph tissue. These models will allow for more complete mechanistic and therapeutic studies in a short time period

Human Prostate Side Population Cells Demonstrate Stem Cell Properties in Recombination with Urogenital Sinus Mesenchyme

<div><p>Stem cell enrichment provides a tool to examine prostate stem cells obtained from benign and malignant tissue. Functional assays can enrich stem cells based on common stem cell phenotypes, such as high ATP binding cassette (ABC) transporter mediated efflux of Hoechst substrates (side population assay). This functional assay is based upon mechanisms that protect cells from environmental insult thus contributing to the survival and protection of the stem cell population. We have isolated and analyzed cells digested from twelve clinical prostate specimens based on the side population assay. Prostate stem cell properties of the isolated cells were tested by serial recombination with rat urogenital mesenchyme. Recombinants with side population cells demonstrate an increase in the frequency of human ductal growth and the number of glands per recombinant when compared to recombinants with non-side population cells. Isolated cells were capable of prostatic growth for up to three generations in the recombination assay with as little as 125 sorted prostate cells. The ability to reproducibly use cells isolated by fluorescence activated cell sorting from human prostate tissue is an essential step to a better understanding of human prostate stem cell biology. ABC transporter G2 (ABCG2) was expressed in recombinants from side population cells indicating the side population cells have self-renewal properties. Epithelial cell differentiation of recombinants was determined by immunohistochemical analysis for expression of the basal, luminal, and neuroendocrine markers, p63, androgen receptor, prostate specific antigen, and chromogranin A, respectively. Thus, the ABCG2 expressing side population demonstrates multipotency and self-renewal properties indicating stem cells are within this population.</p> </div

Expression of Differentiation Markers in Recombinants.

<p>Nonconsecutive serial sections of a recombinant derived from 250 side population cells from specimen NT6+ rUGM were stained. A) H&E staining, box represents area examined at higher power in D–H; B) p63 IHC; C) AR IHC; D) PSA IHC; E) ABCG2 IHC; F) Chromogranin A (ChrA) IHC arrows indicate positive cells; G) telomere (Telo) detection by FISH; and H) DAPI staining. B-H) Scale bar, 10 µm.</p

Incidence of human ductal growth in recombinants with equal number of sorted cells.

*<p>Grafts not analyzed due to host animal death. ND: Not Determined because the recombinant did not demonstrate visible ductal growth upon micro-dissection.</p

Ductal Growth of Recombinants from Side and Non-Side Population Cells.

<p>A) The percentage of recombinants with human ductal growth in the first generation with equal number of sorted cells side population n = 51 and non-sided population n = 52, analyzed by Fisher’s Exact two-sided test p = 0.017. B) The number of glands in recombinants with equal number of sorted cells derived from side population n = 19 and non-side population n = 6 was quantitated and analyzed by Exact Wilcoxon test p = 0.041. C) The percentage of recombinants with human ductal growth in the first generation with representative number of cells side population n = 42 and non-side population n = 45, analyzed by Fisher’s Exact two-sided test p = 1.000. D) The number of glands in recombinants with representative number of cells derived from side population n = 10 and non-side population n = 9 was quantitated and analyzed by Exact Wilcoxon test p = 0.161. E) Kaplan-Meier plot of recombinant survival rate in multiple generations, Logrank test p = 0.2692.</p