RESUMO
By integrating gene profiling and immunohistochemical data with functional experiments in cell lines in this study we show for the first time that doublecortin (DCX) domain containing 2 (DCDC2), a protein belonging to the DCX family and involved in neuronal cell migration, is aberrantly expressed in prostate tumors whereas absent in normal prostate. Furthermore, in patients treated with radical prostatectomy, high levels of DCDC2 RNA were significantly associated with increased biochemical relapse (LogRank Mantel-Cox=0.012). Mechanistically, we found that the ETS transcription factor ESE3/EHF, which is expressed in normal prostate and frequently lost in prostate tumors, maintained DCDC2 repressed by binding to a novel identified ETS binding site in the gene promoter. Consistently, in prostate tumors and in cellular models of gain and loss of ESE3/EHF, the expression of DCDC2 and ESE3/EHF were inversely correlated. In prostate cancer cells, DCDC2 colocalized with microtubules and promoted cell migration and resistance to the microtubule-targeting drug taxol. Collectively, this study establishes DCDC2 as a novel ESE3/EHF oncogenic target in prostate cancer. These findings may be relevant for the clinical management of prostate cancer as DCDC2 may signal tumors more prone to relapse and resistant to taxol treatment.
Assuntos
Resistencia a Medicamentos Antineoplásicos/genética , Proteínas Associadas aos Microtúbulos/genética , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Sítios de Ligação , Movimento Celular/genética , Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Paclitaxel/farmacologia , Regiões Promotoras Genéticas , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/mortalidade , Neoplasias da Próstata/cirurgia , Valores de Referência , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Moduladores de Tubulina/farmacologiaRESUMO
Epigenetic silencing of tumour suppressor genes is an important mechanism involved in cell transformation and tumour progression. The Set and RING-finger-associated domain-containing protein UHRF1 might be an important link between different epigenetic pathways. Here, we report that UHRF1 is frequently overexpressed in human prostate tumours and has an important role in prostate cancer pathogenesis and progression. Analysis of human prostate cancer samples by microarrays and immunohistochemistry showed increased expression of UHRF1 in about half of the cases. Moreover, UHRF1 expression was associated with reduced overall survival after prostatectomy in patients with organ-confined prostate tumours (P < 0.0001). UHRF1 expression was negatively correlated with several tumour suppressor genes and positively with the histone methyltransferase (HMT) EZH2 both in prostate tumours and cell lines. UHRF1 knockdown reduced proliferation, clonogenic capability and anchorage-independent growth of prostate cancer cells. Depletion of UHRF1 resulted in reactivation of several tumour suppressor genes. Gene reactivation upon UHRF1 depletion was associated with changes in histone H3K9 methylation, acetylation and DNA methylation, and impaired binding of the H3K9 HMT Suv39H1 to the promoter of silenced genes. Co-immunoprecipitation experiments showed direct interaction between UHRF1 and Suv39H1. Our data support the notion that UHRF1, along with Suv39H1 and DNA methyltransferases, contributes to epigenetic gene silencing in prostate tumours. This could represent a parallel and convergent pathway to the H3K27 methylation catalyzed by EZH2 to synergistically promote inactivation of tumour suppressor genes. Deregulated expression of UHRF1 is involved in the prostate cancer pathogenesis and might represent a useful marker to distinguish indolent cancer from those at high risk of lethal progression.
Assuntos
Proteínas Estimuladoras de Ligação a CCAAT/genética , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Acetilação , Processos de Crescimento Celular/fisiologia , Linhagem Celular Tumoral , Metilação de DNA , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Progressão da Doença , Proteína Potenciadora do Homólogo 2 de Zeste , Epigênese Genética , Regulação Neoplásica da Expressão Gênica , Inativação Gênica , Genes Supressores de Tumor , Células HEK293 , Histona Metiltransferases , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Histonas/genética , Histonas/metabolismo , Humanos , Imunoprecipitação/métodos , Masculino , Complexo Repressor Polycomb 2/genética , Complexo Repressor Polycomb 2/metabolismo , Regiões Promotoras Genéticas , Neoplasias da Próstata/patologia , Ubiquitina-Proteína LigasesRESUMO
The aim of the present study was to evaluate pharmacological and toxicological properties of (Z)-2-(methylthio)-1-(butyltelluro)-1-phenylethene 1a, (Z)-1-(4-methylphenylsulfonyl)-2-(phenyltelluro)-2-phenylethene 1b, (Z)-2-(butyltelluro)-1-(benzylthio)-1-heptene 1c and (Z)-2-(phenylthio)-1-(butyltelluro)-1-phenylethene 1d. In vitro, vinylic telluride derivatives 1a, 1d and 1c were more effective in reducing lipid peroxidation than compound 1b. The maximal inhibitory effect of vinylic telluride derivatives on lipid peroxidation was in the following order: 1a = 1d > 1c > 1b. Compound 1b was more potent in inhibiting delta-ALA-D activity (delta-aminolevulinate dehydratase) than compounds 1c and 1d. Based on the in vitro properties presented by compounds 1a (an antioxidant) and 1b (a pro-oxidant), toxicological parameters were assessed in vivo and ex vivo in rats. Calculated LD50 of compounds 1a and 1b, administered by oral route, were 20.5 and 1.44 micromol kg(-1), respectively. Compound 1b induced behavioral alterations in the open field test. Renal and spleenic delta-ALA-D activities were inhibited in rats treated orally with compound 1a. Compound 1b stimulated delta-ALA-D activity in liver and spleen of rats. Rats treated with compound 1b had increased hepatic, renal and spleenic lipid peroxidation. Renal and hepatic markers were not altered when compounds 1a and 1b were administered to rats at doses of around LD50, while compound 1a at high doses changed aspartate aminotransferase activity and urea levels. Based on in vitro results, this study demonstrated that compounds 1a and 1d are promising antioxidant compounds. Ex vivo data reinforce compound 1a as a promising drug for more detailed pharmacological studies.