Medicine JournalFeeds

In memoriam of Georg Bartsch, MD, Professor of urology (1942-2012).

Prostate. 2012 Feb 14;

Authors: Culig Z, Klocker H

PMID: 22334563 [PubMed - as supplied by publisher]

A joint effect of new western diet and retinoid X receptor alpha prostate-specific knockout with development of high-grade prostatic intraepithelial neoplasia in mice-A preliminary study.

Prostate. 2012 Feb 7;

Authors: Mao GE, Harris DM, Moro A, Heber D, Roy-Burman P, Zhang ZF, Rao J

Abstract

BACKGROUND: The “New Western-style Diet” (NWD) characterized by high in fat and low in fiber, vitamin D, calcium, and methyl donors-are considered as a risk factor for prostate cancer. Previous studies have shown that premalignant lesions of human prostate have decreased expression of the Retinoid X Receptor alpha (RXRα). This study was to determine the effect of diet in RXRα knockout mice in developing high-grade prostate intraepithelial neoplasia (mPIN). METHODS: Male mice (n = 54) with or without the RXRα prostate null mutation were fed either NWD or AIN-76A control diet for 10 months; prostates were harvested at 11 months of age and examined for prostate mPIN. RESULTS: mPIN was seen in 79% of RXRα prostate null mice fed NWD (n = 19), 30.8% RXRα prostate null mice fed AIN-76A (n = 13), 42.9% RXRα wild-type mice fed NWD (n = 14), and 12.5% RXRα wild-type mice fed AIN-76A (n = 8). Unconditional Logistic analysis showed a significant joint effect of NWD and RXRα status in developing mPIN 26.3 (95% CI: 2.5-280), but interaction was not significant owing to the small sample size 1.6 (0.09-27.7, P = 0.7441). CONCLUSION: This study provides preliminary data to support a joint RXRα-diet effect in prostate carcinogenesis. Prostate © 2012 Wiley Periodicals, Inc.

PMID: 22314496 [PubMed - as supplied by publisher]

Reprogramming of prostate cancer-associated stromal cells to embryonic stem-like.

Prostate. 2012 Feb 7;

Authors: Vêncio EF, Nelson AM, Cavanaugh C, Ware CB, Milller DG, Garcia JC, Vêncio RZ, Loprieno MA, Liu AY

Abstract

BACKGROUND: CD90(+) prostate cancer-associated (CP) stromal cells represent a diseased cell type found only in tumor tissue. They differ from their normal counterpart in gene expression and inductive signaling. Genetic reprogramming by induced pluripotent stem (iPS) cell technology can effectively change adult cells into stem-like cells through wholesale alteration of the gene expression program. This technology might be used to ‘erase’ the abnormal gene expression of diseased cells. The resultant iPS cells would no longer express the disease phenotype, and behave like stem cells. METHODS: CP stromal cells, isolated from tumor tissue of a surgically resected prostate by anti-CD90-mediated sorting and cultured in vitro, were transfected with in vitro packaged lentiviral expression vectors containing stem cell transcription factor genes POU5F1, LIN28, NANOG, and SOX2. RESULTS: Alkaline phosphatase-positive iPS cells were obtained in about 3 weeks post-transfection at a frequency of 10(-4) . Their colony morphology was indistinguishable from that of human embryonic stem (ES) cells. Transcriptome analysis showed a virtually complete match in gene expression between the iPS and ES cells. CONCLUSIONS: Genes of CP stromal cells could be fully inactivated by genetic reprogramming. As a consequence, the disease phenotype was ‘cured’. Prostate © 2012 Wiley Periodicals, Inc.

PMID: 22314551 [PubMed - as supplied by publisher]

Regulation of cell proliferation through a KIT-mediated mechanism in benign prostatic hyperplasia.

Prostate. 2012 Feb 7;

Authors: Imura M, Kojima Y, Kubota Y, Hamakawa T, Yasui T, Sasaki S, Hayashi Y, Kohri K

Abstract

BACKGROUND: We investigated the role of the KIT-mediated mechanism in benign prostatic hyperplasia (BPH), and discuss the pathophysiology of BPH and a candidate target of BPH medical therapy. METHODS: We performed RT-PCR, Western blotting, and immunohistochemistry to examine the expression of KIT in the prostate using a human prostate stromal cell line (PrSC) and human prostate. To investigate the pathophysiological function of KIT, the effects of KIT ligand, stem cell factor (SCF), and imatinib mesylate on cell proliferation were investigated using PrSC. Additionally, we compared the expression level and distribution of KIT in normal prostate and BPH of humans to clarify the contribution of KIT to the pathogenesis of BPH. RESULTS: KIT was expressed in PrSC and human prostate, indicating that these samples are suitable for examining the function of KIT. Immunohistochemical analysis demonstrated that KIT was localized in interstitial cells (ICs) of the stromal component in human prostate. Administration of imatinib mesylate dose-dependently inhibited cell proliferation of PrSC with downregulation of JAK2 and STAT1, which are the main pathways downstream of SCF/KIT signal. SCF promoted cell proliferation of PrSC with upregulation of JAK2 and STAT1. KIT expression and the number of KIT-positive ICs in BPH were found to be significantly larger than in normal prostate. CONCLUSIONS: This is the first report to suggest that KIT regulates cell proliferation in the prostate and plays a significant role in the pathophysiology of BPH. Our study may lead to a greater understanding of the mechanism of BPH and provide a therapeutic target. Prostate © 2012 Wiley Periodicals, Inc.

PMID: 22314612 [PubMed - as supplied by publisher]

miR-141 modulates androgen receptor transcriptional activity in human prostate cancer cells through targeting the small heterodimer partner protein.

Prostate. 2012 Feb 7;

Authors: Xiao J, Gong AY, Eischeid AN, Chen D, Deng C, Young CY, Chen XM

Abstract

BACKGROUND: Aberrant expressions of microRNAs, including upregulation of miR-141, are closely associated with the tumorigenesis of prostate cancer (PCa). The orphan receptor small heterodimer partner (Shp) is a co-repressor to androgen receptor (AR) and represses AR-regulated transcriptional activity. METHODS: Here, we investigated the correlation of Shp expression with the cellular level of miR-141 and its effects on AR transcriptional activity in non-malignant and malignant human prostate epithelial cell lines. RESULTS: We found that Shp was downregulated in multiple PCa cell lines. The mature form of miR-141 was upregulated in PCa cells. miR-141 could target 3′-untranslated region of Shp mRNA resulting in translational suppression and RNA degradation. Moreover, enforced expression of Shp or inhibition of miR-141 function by anti-miR-141 attenuated AR-regulated transcriptional activity in AR-responsive LNCaP cells. Phenethyl isothiocyanate, a natural constituent of many edible cruciferous vegetables, increased Shp expression, downregulated miR-141, and inhibited AR transcriptional activity in LNCaP cells. CONCLUSIONS: Shp is a target for miR-141 and it is downregulated in cultured human PCa cells with the involvement of upregulation of miR-141, which promotes AR transcriptional activity. Moreover, Shp and miR-141 could be targets for chemoprevention for PCa. Prostate © 2012 Wiley Periodicals, Inc.

PMID: 22314666 [PubMed - as supplied by publisher]

Trends in pathologic outcomes after introduction of active surveillance in the UK: Implication for focal therapy.

Prostate. 2012 Feb 10;

Authors: Karavitakis M, Ahmed HU, Abel PD, Livni N, Hazell S, Winkler MH

Abstract

BACKGROUND: We aimed to evaluate the trends in pathologic outcomes of clinically localized prostate cancer treated with radical prostatectomy prior to and after national guidelines placing active surveillance as the primary management in men with low-risk prostate cancer. Further, we examined whether there was a coincident change in the proportion of men potentially suitable for focal therapy. METHODS: All cancer foci in 195 whole mount radical prostatectomy samples during two periods (Period 1: 07/2001-10/2003, n = 100 and Period 2: 01/2007-11/2009, n = 95) were examined. Individual tumor volumes, Gleason grade, and extracapsular extension/positive surgical margins were evaluated. The index lesion was defined as the largest by volume. RESULTS: There was a statistically significant increase in the proportion of Gleason score ≥7 tumors (31-69%; P < 0.001) and pathologically non-organ confined disease (21-37%; P = 0.008), between period 1 and 2, respectively. The proportion of patients with unifocal prostate cancer potentially suitable for focal ablation was stable (14-13.7%; P = 0.9). Although there was a decrease in the proportion of patients potentially suitable for index lesion ablation (51-43%; P = 0.4) and unilateral prostate cancer potentially suitable for hemi-ablation (11-6.3%; P = 0.3), these differences were not statistically significant. CONCLUSION: The increasing use of active surveillance in the UK may be responsible for a trend towards higher grade and stage prostate cancer in whole mount specimens. Despite this, there remain a significant proportion of men who currently undergo radical surgery who may be suitable for focal therapy, if that included index lesion ablation. Prostate © 2012 Wiley Periodicals, Inc.

PMID: 22328187 [PubMed - as supplied by publisher]

Autophagy regulates lipolysis and cell survival through lipid droplet degradation in androgen-sensitive prostate cancer cells.

Prostate. 2012 Jan 31;

Authors: Kaini RR, Sillerud LO, Zhaorigetu S, Hu CA

Abstract

BACKGROUND: Androgen deprivation therapy, one of the standard treatments for prostate cancer (PCa) induces apoptosis, as well as autophagy in androgen-responsive PCa cells. As autophagy can promote either cell survival or death, it is important to understand its role in PCa treatment. The objective of this study was to elucidate the function of autophagy in lipid droplet (LD) homeostasis and survival in androgen-sensitive PCa cells. METHODS: To produce androgen deprivation, charcoal filtered serum or the androgen inhibitor casodex were used in LNCaP and LAPC4 cells. Autophagy was monitored by immunofluorescence/confocal microscopy and immunoblot analysis. Levels of intracellular LDs and triacyglycerols after the inhibition of autophagy by 3-methyladenine, bafilomycin A(1) , or si-ATG5 were quantified by three independent methods, Oil Red O staining, triacyglycerols lipase assay, and nuclear magnetic resonance. RESULTS: Androgen deprivation induced autophagy and the depletion of LDs in both of the androgen-sensitive PCa cell lines examined, whereas the blockage of autophagy by pharmacological or genetic means inhibited LD degradation and therefore lipolysis and cell growth. In addition, under androgen deprivation, increased colocalization of LDs and autophagic vesicles was observed in LNCaP cells, which can be further enhanced by blocking the autophagic flux. CONCLUSION: Autophagy mediates LD degradation and lipolysis in androgen-sensitive PCa cells during androgen deprivation which aids the survival of PCa cells during hormone therapy. Prostate © 2012 Wiley Periodicals, Inc.

PMID: 22294520 [PubMed - as supplied by publisher]

A Hoxb13-driven reverse tetracycline transactivator system for conditional gene expression in the prostate.

Prostate. 2012 Feb 1;

Authors: Rao V, Heard JC, Ghaffari H, Wali A, Mutton LN, Bieberich CJ

Abstract

BACKGROUND: Genetically engineered mouse models play important roles in analyses of prostate development and pathobiology. While constitutive genetic gain- and loss-of-function models have contributed significantly to our understanding of molecular events driving these processes, the availability of a tightly regulated inducible expression system could extend the utility of transgenic approaches. Here, we describe the development of a Tet-regulatory system that employs Hoxb13 transcriptional control elements to direct reverse tetracycline transactivator (rtTA) expression in the prostate. METHODS: Using recombineering technology, the rtTA gene was placed under Hoxb13 cis-regulatory transcriptional control in the context of a 218-kb bacterial artificial chromosome. F(1) offspring carrying the Hoxb13-rtTA transgene were bred to a Tetracycline operator-Histone 2B-Green Fluorescent Protein (TetO-H2BGFP) responder line. Detailed reporter gene expression analyses, including doxycycline (Dox) induction and withdrawal kinetics, were performed in Hoxb13-rtTA|TetO-H2BGFP double transgenic adult mice and embryos. RESULTS: Dox-dependent GFP expression was observed exclusively in the prostate and distal colon epithelia of double transgenic mice. Reporter gene mRNA was detected in the prostate within 6 hr of Dox exposure, and was extinguished within 24 hr after Dox withdrawal. Furthermore, Dox-induced reporter gene expression persisted after castration. CONCLUSIONS: The Hoxb13-rtTA transgenic system provides a powerful tool for conditional Tet operator-driven transgene expression in the normal prostate and during disease progression. Used in conjunction with other prostate pathology models, these mice will enable precise, temporally controlled analyses of gene function and can provide opportunities for detailed analyses of molecular events underlying prostate diseases. Prostate © 2012 Wiley Periodicals, Inc.

PMID: 22297979 [PubMed - as supplied by publisher]

A panel of five circulating microRNAs as potential biomarkers for prostate cancer.

Prostate. 2012 Feb 1;

Authors: Chen ZH, Zhang GL, Li HR, Luo JD, Li ZX, Chen GM, Yang J

Abstract

BACKGROUND: Circulating microRNA (miRNAs) have been shown to have the potential as noninvasive diagnosis markers in several types of cancers. In this study, we investigated whether circulating miRNAs could be used in the diagnosis of prostate cancer (CaP) in a Chinese patient population. METHODS: Illumina’s Human v2 miRNA microarray was used to analyze miRNAs levels in a small set of patients [25 CaP, 17 benign prostatic hyperplasia (BPH)] in an effort to identify CaP-specific miRNAs. The identified miRNAs were further examined by quantitative real-time PCR (qRT-PCR) in the same small set of patients. After the training phase of screening and selecting, the candidate miRNAs were validated in a larger independent cohort (80 CaP, 44 BPH, and 54 healthy controls) with qRT-PCR in the verification phase. RESULTS: Five miRNAs were confirmed by qRT-PCR analysis in validation sets. Receiver operating characteristic (ROC) curve analysis showed all 5 miRNAs had diagnostic value. More importantly, further principal component analysis indicated component 1 extracted from expression data of the 5 miRNAs could differentiate CaP from BPH and healthy controls with high diagnosis performance, with an AUC of 0.924 and 0.860, respectively. CONCLUSIONS: Our data suggested that circulating miRNAs could serve as biomarkers for CaP, and compared to single miRNA, the 5 miRNAs panel can accurately discriminate CaP from BPH and healthy controls with high sensitivity and specificity, and therefore, combined with routine PSA test, these 5 CaP-specific miRNAs may help improve CaP diagnosis in clinical application. Prostate © 2012 Wiley Periodicals, Inc.

PMID: 22298030 [PubMed - as supplied by publisher]

Dysregulation of circulating microRNAs and prediction of aggressive prostate cancer.

Prostate. 2012 Feb 1;

Authors: Shen J, Hruby GW, McKiernan JM, Gurvich I, Lipsky MJ, Benson MC, Santella RM

Abstract

BACKGROUND: It is becoming increasingly evident that microRNAs (miRNAs) are associated with the development and progression of prostate cancer (PCa). METHODS: We examined the hypothesis that plasma miRNA levels can differentiate patients by aggressiveness in 82 PCa patients. Taqman based quantitative RT-PCR assays were performed to measure copy number of target miRNAs. RESULTS: miR-20a was significantly overexpressed in plasma from patients with stage 3 tumors compared to stage 2 or below (P = 0.03). The expression levels for miR-20a and miR-21 were significantly increased in patients with high risk CAPRA scores (16,623 and 1,595 copies, respectively). Significantly increased miR-21 and miR-145 expression were observed for patients with intermediate or high risk D’Amico scores compared to patients with low risk scores (P = 0.047 and 0.011, respectively). The relapse rates for CAPRA scores ranged from 1.9% for low risk to 9.5% for intermediate risk and to 22.2% for high risk patients (P = 0.023). For D’Amico scores, the relapse rates ranged from 0.0% for low risk to 7.4% for intermediate risk and 17.6% for high risk patients (P = 0.039). Expression of miR-21 and miR-221 significantly differentiated patients with intermediate risk from those with low risk CAPRA scores (AUC = 0.801, P = 0.002). Four miRNAs (miR-20a, miR-21, miR-145, and miR-221) could also distinguish high versus low risk in PCa patients by D’Amico score with an AUC of 0.824. CONCLUSIONS: These preliminary data suggest that altered plasma miRNAs may be useful predictors to distinguish PCa patients with varied aggressiveness. Further larger studies to validate this promising finding are warranted. Prostate © 2012 Wiley Periodicals, Inc.

PMID: 22298119 [PubMed - as supplied by publisher]