In the clinical management of prostate cancer (PCa) an early discrimination between aggressive and indolent forms of the disease is of paramount importance. We have contributed to this goal by identifying: 1) the catalytic subunit of telomerase and the estrogenic receptors as potential therapeutic targets in PCa (Misiti et al MCB 2000; Nanni et al JCI 2002) and 2) a prognostic signature in primary epithelial cell cultures (n=50) generated from fresh explants of PCa at different disease stages (Nanni et al. MCR 2006). We have then defined (Grasselli et al Circ Res 2008; Nanni et al JCI 2009) a molecular mechanism involving functional activation of endothelial nitric oxide synthase (eNOS) and hypoxia-inducible factors (HIFs) in association with the estrogen receptor beta (ER?) that characterizes the most aggressive form of PCa. Cells from patients with poor prognosis exhibited a constitutively hypoxic phenotype and increased NO production. We also provided evidence by ChIPs and re-ChIPs assays for the existence and prognostic role in human PCa of functional complexes between ER? and HIF-1?/2? or eNOS. Altogether these data led us to postulate that activation of eNOS is a crucial requirement toward acquisition of androgen-independence and tumor progression in the prostate microenvironment highly sensitive to abnormal estrogen stimulation and/or variations in the intracellular levels of oxygen and NO. Overall our findings strongly support a model where eNOS functions as a co-factor of ERs in gene transcription, and formation of eNOS/ERs complexes induces localized chromatin remodelling, leading to transcriptional regulation of previously identified prognostic genes (e.g. hTERT, MSH2, Cyclin B1 and PS2), with major effects on the acquisition of a malignant phenotype by human prostate epithelial cells. We are currently analysing eNOS-containing complexes bound to DNA by Mass Spectrometry after Chromatin Immunoprecipitation using anti-eNOS antibodies. In parallel, the identification of genes that may be differentially targeted by nuclear eNOS will be performed by high resolution analysis using the ChIP-Sequencing technology approach.
Functional role of the eNOS/ER? combinatorial complex in the progression of prostate cancer: transcriptional regulation of prognostic genes.
A Farsetti
2010
Abstract
In the clinical management of prostate cancer (PCa) an early discrimination between aggressive and indolent forms of the disease is of paramount importance. We have contributed to this goal by identifying: 1) the catalytic subunit of telomerase and the estrogenic receptors as potential therapeutic targets in PCa (Misiti et al MCB 2000; Nanni et al JCI 2002) and 2) a prognostic signature in primary epithelial cell cultures (n=50) generated from fresh explants of PCa at different disease stages (Nanni et al. MCR 2006). We have then defined (Grasselli et al Circ Res 2008; Nanni et al JCI 2009) a molecular mechanism involving functional activation of endothelial nitric oxide synthase (eNOS) and hypoxia-inducible factors (HIFs) in association with the estrogen receptor beta (ER?) that characterizes the most aggressive form of PCa. Cells from patients with poor prognosis exhibited a constitutively hypoxic phenotype and increased NO production. We also provided evidence by ChIPs and re-ChIPs assays for the existence and prognostic role in human PCa of functional complexes between ER? and HIF-1?/2? or eNOS. Altogether these data led us to postulate that activation of eNOS is a crucial requirement toward acquisition of androgen-independence and tumor progression in the prostate microenvironment highly sensitive to abnormal estrogen stimulation and/or variations in the intracellular levels of oxygen and NO. Overall our findings strongly support a model where eNOS functions as a co-factor of ERs in gene transcription, and formation of eNOS/ERs complexes induces localized chromatin remodelling, leading to transcriptional regulation of previously identified prognostic genes (e.g. hTERT, MSH2, Cyclin B1 and PS2), with major effects on the acquisition of a malignant phenotype by human prostate epithelial cells. We are currently analysing eNOS-containing complexes bound to DNA by Mass Spectrometry after Chromatin Immunoprecipitation using anti-eNOS antibodies. In parallel, the identification of genes that may be differentially targeted by nuclear eNOS will be performed by high resolution analysis using the ChIP-Sequencing technology approach.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
