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Philip Rosen,
David Pfister,
Denise Young, Gyorgy Petrovics,
Yongmei Chen,
Jennifer Cullen,
Diana Böhm,
Sven Perner,
Albert Dobi,
David G McLeod,
Isabell A Sesterhenn,
Shiv Srivastava
[show abstract]
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ABSTRACT: To systematically evaluate the ETS-related gene (ERG) alterations in the multifocal tumor context using whole-mount prostatectomy specimens from African and Caucasian American patients matched for age, pathologic grade and stage. Oncogenic activation of the ERG is the most common early genomic alteration in patients with prostate cancer (CaP) in Western countries. However, ERG alterations have not been systematically examined in African American patients with a known greater risk of CaP incidence and mortality.
ERG oncoprotein expression was analyzed in 91 Caucasian and 91 African American patients with CaP, who were matched for age, Gleason score, and pathologic stage. A unique aspect of the present study was the evaluation of ERG in whole-mount prostatectomy sections, minimizing sampling bias and allowing the careful assessment of the ERG in the multifocal tumor context of CaP.
The frequency of ERG-positive prostate tumors was significantly greater among Caucasian Americans than among African Americans when assessed in all tumor foci (41.9% vs 23.9%, P < .0001). A markedly greater frequency of ERG oncoprotein expression was noted between the index tumors of the Caucasian Americans (63.3%) and those of the African Americans (28.6%). Also, in the African American patients, the higher grade index tumors were predominantly ERG negative.
ERG typing of CaP established a major difference between the index tumors of Caucasian and African American patients. ERG-negative index tumors might indicate a less favorable outcome for African American patients. The results of the present study underscore that typing of CaP for the ERG could enhance our understanding of the biologic differences between the examined ethnic groups.
Urology 08/2012; 80(4):749-53. · 2.43 Impact Factor
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Asian Journal of Andrology 06/2011; 13(5):659-60. · 1.52 Impact Factor
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Ahmed A Mohamed,
Shyh-Han Tan,
Chen Sun,
Syed Shaheduzzaman,
Ying Hu, Gyorgy Petrovics,
Yongmei Chen,
Isabell A Sesterhenn,
Hua Li,
Taduru Sreenath,
David G McLeod,
Albert Dobi,
Shiv Srivastava
[show abstract]
[hide abstract]
ABSTRACT: Androgen dependent induction of the ETS related gene (ERG) expression in more than half of all prostate cancers results from gene fusions involving regulatory sequence of androgen regulated genes (i.e. TMPRSS2, SLC45A3 and NDRG1) and protein coding sequence of the ERG. Emerging studies in experimental models underscore the functions of ERG in prostate tumorigenesis. However, biological and biochemical functions of ERG in prostate cancer (CaP) remain to be elucidated. This study suggests that ERG activation plays a role in prostaglandin signaling because knockdown of ERG expression in TMPRSS2-ERG fusion containing CaP cells leads to altered levels of the 15-hydroxy-prostaglandin dehydrogenase (HPGD), a tumor suppressor and prostaglandin catabolizing enzyme, and prostaglandin E2 (PGE2) . We demonstrate that HPGD expression is regulated by the binding of the ERG protein to the core promoter of this gene. Moreover, prostaglandin E2 dependent cell growth and urokinase-type plasminogen activator (uPA) expression are also affected by ERG knockdown. Together, these data imply that the ERG oncoprotein in CaP cells positively influence prostaglandin mediated signaling, which may contribute to tumor progression.
Cancer biology & therapy 02/2011; 11(4):410-7. · 2.64 Impact Factor
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[show abstract]
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ABSTRACT: Prevalent gene fusions involving regulatory sequences of the androgen receptor (AR) regulated genes (primarily TMPRSS2) and protein coding sequences of nuclear transcription factors of the ETS gene family (predominantly ERG) result in unscheduled androgen dependent ERG expression in prostate cancer (CaP).Cumulative data from a large number of studies in the past six years accentuate ERG alterations in more than half of all CaP patients in Western countries. Studies underscore that ERG functions are involved in the biology of CaP. ERG expression in normal context is selective to endothelial cells, specific hematopoetic cells and pre-cartilage cells. Normal functions of ERG are highlighted in hematopoetic stem cells. Emerging data continues to unravel molecular and cellular mechanisms by which ERG may contribute to CaP. Herein, we focus on biological and clinical aspects of ERG oncogenic alterations, potential of ERG-based stratification of CaP and the possibilities of targeting the ERG network in developing new therapeutic strategies for the disease.
Journal of Carcinogenesis 01/2011; 10:37.
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Bungo Furusato,
Toshiyuki Tsunoda,
Syed Shaheduzzaman,
Martin E Nau,
Maryanne Vahey, Gyorgy Petrovics,
David G McLeod,
Seiji Naito,
Senji Shirasawa,
Shiv Srivastava,
Isabell A Sesterhenn
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ABSTRACT: To better understand the gene expression patterns in tumor-associated stroma, laser-capture-microdissections from clinical specimens were analyzed by genome-wide-expression microarray technology. The epithelial-stromal interaction plays a critical role in prostate development, reactive changes, and tumorigenesis. Diverse microarray technologies have been used to characterize the molecular changes in prostate cancer. Even though these gene expression studies are compromised by the heterogeneity of the tumor, as well as by the difficulty associated with collecting appropriate counterparts to represent normal prostate cells, the gene array data from tumors have shown promising results. Currently, little is known about the tumor-associated stromal gene expression profile in prostate cancer.
Matching benign and malignant epithelial cell-related stroma cells were subjected to microarray platforms.
The prostatatic stroma expressed several osteogenic molecules. In particular, one of the genes, OSF2, was upregulated in tumor-associated stroma compared with benign epithelial cell associated stroma, which was further validated by immunohistochemical examination.
These data show that the combination of laser capture dissection with computational enhancement of epithelial and stromal microarray data is a useful tool to assess gene expression changes in prostate cancer stroma.
Urology 04/2010; 75(4):768-72. · 2.43 Impact Factor
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Kevin R Rice,
Yongmei Chen,
Amina Ali,
Eric J Whitman,
Amy Blase,
Mona Ibrahim,
Sally Elsamanoudi,
Stephen Brassell,
Bungo Furusato,
Norbert Stingle,
Isabell A Sesterhenn, Gyorgy Petrovics,
Siobhan Miick,
Harry Rittenhouse,
Jack Groskopf,
David G McLeod,
Shiv Srivastava
[show abstract]
[hide abstract]
ABSTRACT: Prevalent gene fusions in prostate cancer involve androgen-regulated promoters (primarily TMPRSS2) and ETS transcription factors (predominantly ETS-regulated gene (ERG)], which result in tumor selective overexpression of ERG in two thirds of patients. Because diverse genomic fusion events lead to ERG overexpression in prostate cancer, we reasoned that it may be more practical to capture such alterations using an assay targeting ERG sequences retained in such gene fusions. This study evaluates the potential of an assay quantitating ERG mRNA in post-digital rectal exam (DRE) urine for improving prostate cancer detection.
Patients scheduled to undergo transrectal ultrasound-guided needle biopsy of the prostate were prospectively enrolled. On the day of biopsy, patients provided a urine sample immediately following a DRE. Urine ERG mRNA was measured and normalized to urine prostate-specific antigen (PSA) mRNA using the DTS 400 system. Demographic traits, clinical characteristics and biopsy results were analyzed for association with urine ERG score.
The study was conducted on 237 patients. Prostate cancer was shown on biopsy in 40.9% of study subjects. A higher urine ERG score associated significantly with malignancy on biopsy (P = 0.0145), but not with clinical stage or Gleason score. Urine ERG score performed best in Caucasians and in men with a PSA of <or=4 ng/mL (area under the curve = 0.8).
A higher urine ERG score in post-DRE urine is associated with the diagnosis of prostate cancer on biopsy. Urine ERG score performed particularly well in men with a PSA of <or=4.0 ng/mL, a segment of the screening population in which further diagnostic markers are needed to determine in whom biopsy should be done.
Clinical Cancer Research 02/2010; 16(5):1572-6. · 7.74 Impact Factor
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Eric J Whitman,
Mark Pomerantz,
Yongmei Chen,
Michael M Chamberlin,
Bungo Furusato,
Chunling Gao,
Amina Ali,
Lakshmi Ravindranath,
Albert Dobi,
Isabell A Sesterhenn,
Isabell A Sestrehenn,
David G McLeod,
Shiv Srivastava,
Matthew Freedman, Gyorgy Petrovics
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ABSTRACT: A region on chromosome 8q24 was recently identified as a novel prostate cancer risk locus. Inherited variation in this region is associated with prostate cancer risk in the general population (21-58%), and specific alleles show a strong association in African-American men. This study was designed to evaluate associations between 8q24 risk alleles and clinical variables, such as pathologic stage, age at diagnosis, and recurrence, in a case series of African-American men.
Peripheral blood DNA samples from 114 African-American men with prostate cancer, including 106 who had undergone radical prostatectomy, were genotyped for six single-nucleotide polymorphisms on three 8q24 regions. The presence of these single-nucleotide polymorphisms was compared with clinicopathologic and follow-up data after radical prostatectomy.
The mean age of diagnosis and follow-up time were 57.4 (+/-8.9) years and 49.1 (+/-31.6) months, respectively. Patients carrying the Broad11934905 A risk allele, which is specific for African ancestry, were more likely to have a higher pathologic stage (pT(3-4)) than individuals with the wild type (odds ratio, 4.48; 95% confidence interval, 1.42-14.14; P = 0.011). A trend toward increased frequency of and shorter time to biochemical recurrence was noted in patients with this risk allele on Kaplan-Meier unadjusted survival analysis (P = 0.076).
The Broad11934905 polymorphism at 8q24, which is only found in people of African ancestry, is associated with an increase in non-organ-confined prostate cancer at prostatectomy. In addition, for those with this risk allele, there is a trend toward early biochemical recurrence that requires validation in larger studies.
Cancer Epidemiology Biomarkers & Prevention 01/2010; 19(1):1-8. · 4.12 Impact Factor
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Mark M Pomerantz,
Christine A Beckwith,
Meredith M Regan,
Stacia K Wyman, Gyorgy Petrovics,
Yongmei Chen,
Dorota J Hawksworth,
Fredrick R Schumacher,
Lorelei Mucci,
Kathryn L Penney, [......],
Daniel W Lin,
Michelle Dyke,
Paula Herman,
Steve Lee,
William K Oh,
Philip W Kantoff,
Muneesh Tewari,
David G McLeod,
Shiv Srivastava,
Matthew L Freedman
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ABSTRACT: Polymorphisms at 8q24 are robustly associated with prostate cancer risk. The risk variants are located in nonprotein coding regions and their mechanism has not been fully elucidated. To further dissect the function of this locus, we tested two hypotheses: (a) unannotated microRNAs (miRNA) are transcribed in the region, and (b) this region is a cis-acting enhancer. Using next generation sequencing, 8q24 risk regions were interrogated for known and novel miRNAs in histologically normal radical prostatectomy tissue. We also evaluated the association between the risk variants and transcript levels of multiple genes, focusing on the proto-oncogene, MYC. RNA expression was measured in histologically normal and tumor tissue from 280 prostatectomy specimens (from 234 European American and 46 African American patients), and paired germline DNA from each individual was genotyped for six 8q24 risk single nucleotide polymorphisms. No evidence was found for significant miRNA transcription within 8q24 prostate cancer risk loci. Likewise, no convincing association between RNA expression and risk allele status was detected in either histologically normal or tumor tissue. To our knowledge, this is one of the first and largest studies to directly assess miRNA in this region and to systematically measure MYC expression levels in prostate tissue in relation to inherited risk variants. These data will help to direct the future study of this risk locus.
Cancer Research 07/2009; 69(13):5568-74. · 7.86 Impact Factor
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Eric J Whitman,
Jack Groskopf,
Amina Ali,
Yongmei Chen,
Amy Blase,
Bungo Furusato, Gyorgy Petrovics,
Mona Ibrahim,
Sally Elsamanoudi,
Jennifer Cullen,
Isabell A Sesterhenn,
Stephen Brassell,
Harry Rittenhouse,
Shiv Srivastava,
David G McLeod
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ABSTRACT: PCA3 is a prostate specific, nonprotein coding RNA that is over expressed in prostate cancer. Recent studies showed the diagnostic potential of a urine based PCA3 for predicting biopsy outcome. We assessed the relationship between urine PCA3 and pathological features in whole mount radical prostatectomy specimens.
Post-digital rectal examination urine specimens were obtained from 72 men with prostate cancer before radical prostatectomy. PCA3 and PSA mRNA were measured. The ratio of PCA3 to PSA mRNA was recorded as a PCA3 score and correlated with data on each prostate specimen.
Patients with extracapsular extension had a significantly higher median PCA3 score than patients without extracapsular extension (48.8 vs 18.7, p = 0.02). PCA3 score significantly correlated with total tumor volume (r = 0.38, p <0.01). On multivariate analysis PCA3 score was an independent predictor of extracapsular extension (p = 0.01) and total tumor volume less than 0.5 cc (p = 0.04). At a cutoff PCA3 score of 47 extracapsular extension was predicted with 94% specificity and an 80% positive predictive value. When combined with serum PSA and biopsy Gleason score, the ROC AUC for predicting extracapsular extension was 0.90.
PCA3 detected in the post-digital rectal examination urine of patients with prostate cancer correlated with pathological findings. Therefore, it could provide prognostic information. To our knowledge this is the first report of a molecular urine assay that predicts extracapsular extension.
The Journal of urology 10/2008; 180(5):1975-8; discussion 1978-9. · 4.02 Impact Factor
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Ying Hu,
Albert Dobi,
Taduru Sreenath,
Christopher Cook,
Atekelt Y Tadase,
Lakshmi Ravindranath,
Jennifer Cullen,
Bungo Furusato,
Yongmei Chen,
Rajesh L Thangapazham,
Ahmed Mohamed,
Chen Sun,
Isabell A Sesterhenn,
David G McLeod, Gyorgy Petrovics,
Shiv Srivastava
[show abstract]
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ABSTRACT: The expression of the ETS-related gene (ERG) is low or undetectable in benign prostate epithelial cells. High prevalence of ERG overexpression in prostate cancer cells due to TMPRSS2-ERG fusions suggest for causal roles of ERG protein in the neoplastic process. TMPRSS2-ERG fusion junctions have been extensively studied in prostate cancer. However, virtually nothing is known about the nature of full-length transcripts and encoded proteins. This study focuses on qualitative and quantitative features of full-length TMPRSS2-ERG transcripts in prostate cancer.
Full-length TMPRSS2-ERG transcripts were cloned and sequenced from a cDNA library generated from pooled RNA of six TMPRSS2-ERG fusion-positive prostate tumors. The encoded ERG proteins were analyzed in HEK293 cells. Copy numbers of TMPRSS2-ERG splice variants were determined by quantitative reverse transcription-PCR in laser capture microdissected prostate cancer cells.
Two types of TMPRSS2-ERG cDNAs were identified: type I, which encodes full-length prototypical ERG protein (ERG1, ERG2, ERG3), and type II, encoding truncated ERG proteins lacking the ETS domain (ERG8 and a new variant, TEPC). In microdissected prostate tumor cells from 122 patients, relative abundance of these variants was in the following order: ERG8 > TEPC > ERG 3 > ERG1/2 with combined overexpression rate of 62.3% in prostate cancer. Increased ratio of type I over type II splice forms showed a trend of correlation with less favorable pathology and outcome.
Qualitative and quantitative features of specific ERG splice variants defined here promise to enhance the utility of ERG as a biomarker and therapeutic target in prostate cancer.
Clinical Cancer Research 08/2008; 14(15):4719-25. · 7.74 Impact Factor
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[show abstract]
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ABSTRACT: TMPRSS2-ERG gene fusion leading to the androgenic induction of the ERG proto-oncogene expression is a highly prevalent oncogenic alteration in prostate tumor cells. Prostate cancer is a multi-focal disease, and the origins as well as biological contribution of multiple cancer foci remain unclear with respect to prostate cancer onset or progression. To assess the role of TMPRSS2-ERG alteration in prostate cancer onset and/or progression, we have evaluated the status of fusion transcripts in benign glands, prostatic intraepithelial neoplasia (PIN) and multiple cancer foci of each prostate. Quantitative expression of TMPRSS2-ERG fusion type A and C transcripts was analyzed in benign, tumor and PIN areas, selected from whole-mount radical prostatectomy slides. TMPRSS2-ERG expression was correlated with clinicopathological features. Overall, 30 of 45 (67%) patients exhibited TMPRSS2-ERG fusion transcripts in at least one tumor focus. Of 80 tumor foci analyzed, 39 had TMPRSS2-ERG fusion (type A only: 30, type C only: 2, both types A and C: 7), with predominant detection of the TMPRSS2-ERG fusion type A (27/30, 90%) in the index tumors. Of 14 PIN lesions, 2 were positive for type A fusion. Frequent presence of the TMPRSS2-ERG in index tumors suggests critical roles of ERG alterations in the onset and progression of a large subset of prostate cancer. However, heterogeneity of the TMPRSS2-ERG detection in the context of multiple cancer foci and its frequency in PIN also support the role of other genomic alterations in the origins of prostate cancer.
Modern Pathology 03/2008; 21(2):67-75. · 4.79 Impact Factor
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Joseph R Sterbis,
Chunling Gao,
Bungo Furusato,
Yongmei Chen,
Syed Shaheduzzaman,
Lakshmi Ravindranath,
David J Osborn,
Inger L Rosner,
Albert Dobi,
David G McLeod,
Isabell A Sesterhenn,
Shiv Srivastava,
Jennifer Cullen, Gyorgy Petrovics
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ABSTRACT: Alterations of the androgen receptor (AR)-mediated signaling through numerous mechanisms are increasingly recognized in prostate cancer (CaP) progression. We hypothesized that the assessment of well-defined AR transcriptional targets (e.g., PSA/HK3 mRNA) in CaP tissues will provide in vivo readout of AR dysfunctions. Moreover, quantitative expression features of PSA/HK3 mRNA in prostate tumor cells may serve as a prognostic indicator of disease progression.
Paired benign and malignant epithelial cells (242 specimens) were obtained from laser capture microdissection of frozen OCT-embedded tissue sections prepared from radical prostatectomy specimens of 121 patients. Quantitative expression of PSA/HK3 mRNA in the matched malignant and benign cells was analyzed by real-time reverse transcription-PCR.
CaP cells express significantly lower PSA/HK3 mRNA levels than matched benign cells (P = 0.0133). Moreover, low PSA/HK3 mRNA expression in malignant cells was associated with increased risk of biochemical recurrence (P = 0.0217), as well as with time to recurrence (P = 0.0371), in patients with intermediate preoperative serum prostate-specific antigen levels (2-10 ng/mL). The expression of androgen-dependent genes in clinical samples correlates with each other in patients with higher expression of PSA/HK3 mRNA but not in patients with lower expression of PSA/HK3 mRNA reflecting AR pathway dysfunction.
Our study has unraveled a novel prognostic utility of quantitative measurements of PSA/HK3 mRNA reflecting AR transcriptional activity in CaP cells, which is independent of serum prostate-specific antigen. It also has potential in stratifying subsets of patients exhibiting progressive disease associated with dampened AR transcriptional functions who may be targeted by tailored therapeutic strategies.
Clinical Cancer Research 03/2008; 14(3):758-63. · 7.74 Impact Factor
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ABSTRACT: Alterations of androgen receptor (AR) functions caused by overexpression, amplification, or mutation have been described in a significant subset of advanced prostate cancer (CaP). Because AR mutations or amplification are rare in early stage CaP, we hypothesized that altered AR expression in prostate tumor cells may provide a prognostic indicator of disease progression.
RNA from laser capture microdissected (LCM) tumor and benign epithelial cells from radical prostatectomy specimens of 115 hormone-naive patients were studied. Expression of AR and GAPDH genes were measured by duplex quantitative real-time polymerase chain reaction (RT-PCR) in 230 specimens. A ratio of the expression of AR gene, normalized to GAPDH gene expression in the same specimens, was compared in tumor and benign epithelial cells (tumor-to-benign ratio) and correlated with clinicopathologic features.
Paired t test analysis revealed a 62% lower AR expression in tumor tissue compared with benign tissue (P = 0.0005). However, multivariate Cox proportional hazards regression analysis of time to PSA recurrence revealed that higher tumor cell associated AR expression (continuous, log-transformed), significantly increases odds of prostate-specific antigen (PSA) recurrence (P = 0.0139) when controlling for age at surgery, race, time from diagnosis to surgery, risk stratification, pathologic T stage, Gleason sum, and margin status.
Quantitative determination of AR gene expression levels in prostate epithelial cells may be useful for predicting PSA recurrence. This study supports the accumulating data suggesting that gain of AR function may contribute to CaP progression.
Urology 01/2008; 70(6):1225-9. · 2.43 Impact Factor
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ABSTRACT: To investigate molecular alterations associating with prostate carcinoma progression and potentially provide information toward more accurate prognosis/diagnosis.
A set of laser captured microdissected (LCM) specimens from 300 prostate cancer (PCa) patients undergoing radical prostatectomy (RP) were defined. Ten patients representing "aggressive" PCa, and 10 representing "non-aggressive" PCa were selected based on prostate-specific antigen (PSA) recurrence, Gleason score, pathological stage and tumor cell differentiation, with matched patient age and race between the two groups. Normal and neoplastic prostate epithelial cells were collected with LCM from frozen tissue slides obtained from the RP specimens. The expressions of a panel of genes, including NPY, PTEN, AR, AMACR, DD3, and GSTP1, were measured by quantitative real-time RT-PCR (TaqMan), and correlation was analyzed with clinicopathological features.
The expressions of AMACR and DD3 were consistently up-regulated in cancer cells compared to benign prostate epithelial cells in all PCa patients, whereas GSTP1 expression was down regulated in each patient. NPY, PTEN and AR exhibited a striking difference in their expression patterns between aggressive and non-aggressive PCas (P=0.0203, 0.0284, and 0.0378, respectively, Wilcoxon rank sum test). The lower expression of NPY showed association with "aggressive" PCas based on a larger PCa patient cohort analysis (P=0.0037, univariate generalized linear model (GLM) analysis).
Despite widely noted heterogeneous nature of PCa, gene expression alterations of AMACR, DD3, and GSTP1 in LCM-derived PCa epithelial cells suggest for common underlying mechanisms in the initiation of PCa. Lower NPY expression level is significantly associated with more aggressive clinical behavior of PCa; PTEN and AR may have potential in defining PCa with aggressive clinical behavior. Studies along these lines have potential to define PCa-associated gene expression alterations and likely co-regulation of genes/pathways critical in the biology of PCa onset/progression.
Journal of Zhejiang University SCIENCE B 01/2008; 8(12):853-9. · 1.10 Impact Factor
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Syed Shaheduzzaman,
Anu Vishwanath,
Bungo Furusato,
Jennifer Cullen,
Yongmei Chen,
Lionel Bañez,
Martin Nau,
Lakshmi Ravindranath,
Kee-Hong Kim,
Ahmed Mohammed,
Yidong Chen,
Mathias Ehrich,
Vasantha Srikantan,
Isabell A Sesterhenn,
David McLeod,
Maryanne Vahey, Gyorgy Petrovics,
Albert Dobi,
Shiv Srivastava
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ABSTRACT: Cancer cells gain selection advantages by the coordinated silencing of protective and by the activation of cell proliferation/cell survival genes. Evaluations of epithelial cell transcriptome of benign and malignant prostate glands by laser capture microdissection (LCM) identified Lactotransferrin (LTF) as the most significantly downregulated gene in prostate cancer (CaP) cells (p < 10(-6)). Frequent downregulation, significant association of LTF with PSA recurrence-free survival in CaP patients and the established anti-tumorigenic effects of LTF in experimental cancer models have provided impetus to evaluate LTF expression features and mechanisms in CaP specimens.
LTF mRNA expression analysis was performed in LCM derived benign and malignant prostate epithelial cells by using Affymetrix GeneChip and QRT-PCR. LTF protein expression was assessed in tissue specimens by immunohistochemistry and in serum samples from CaP patients compared to healthy male control by using ELISA. Mechanism of LTF downregulation was analyzed in 5-azadeoxycytidine treated LNCaP and LAPC4 cells using MALDI-TOF MS. Proliferation and cell cycle analysis of CaP cells by FACS flow cytrometry was assessed in LNCaP cell cultures.
Quantitative analysis of LTF mRNA expression in tumor cells revealed marked downregulation of LTF with significant associations to decreased PSA recurrence-free survival of CaP patients (n = 100, p < or = 0.0322). Moreover, low levels of LTF protein expression was observed in tumor tissues as well as in sera from CaP patients (p < or = 0.0001). LTF promoter downstream CpG island methylation was found in LNCaP and LAPC4 cells. Furthermore, replenishing of LTF by supplementing growth media with LTF protein resulted in reduced cell growth. Cell cycle analysis revealed robust increases in apoptosis in response to LTF treatment.
This study highlights the potential for LTF in chemoprevention and to become a biologically relevant prognostic marker of CaP, suggesting that silencing of the LTF gene may be causally linked to CaP progression.
Cancer biology & therapy 07/2007; 6(7):1088-95. · 2.64 Impact Factor
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Mei Sun,
Vasantha Srikantan,
Lanfeng Ma,
Jia Li,
Wei Zhang, Gyorgy Petrovics,
Mazen Makarem,
Jeffrey W Strovel,
Stephen G Horrigan,
Meena Augustus,
Isabell A Sesterhenn,
Judd W Moul,
Settara Chandrasekharappa,
Zhiqiang Zou,
Shiv Srivastava
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ABSTRACT: The long arm of chromosome 6 is frequently deleted in diverse human neoplasms. Our previous study showed a minimum deletion region between markers D6S1056 and D6S300 on chromosome 6q in primary prostate cancer (CaP). In this study, we further refined a 200-kb minimal region of deletion (6qTSG1) centered around D6S1013 marker. The 6qTSG1 transcripts contained complex multiple splicing variants with low or absent expression in CaP cells. None of the transcripts identified contained open reading frames that code for a protein in the NCBI database. The expression of 6qTSG transcripts revealed interesting hormonal regulation relevant to CaP biology. Expression of 6q TSG transcript was induced in LNCaP cells that were cultured in charcoal-stripped serum medium suggesting an upregulation of 6qTSG transcript by androgen ablation and cell growth inhibition/apoptosis. Induction of 6qTSG1 expression in response to androgen ablation was abrogated in androgen-independent derivatives of LNCaP cells. In summary, we have defined a candidate CaP suppressor locus on chromosome 6q16.1, and deletions of this locus are frequently associated with prostate tumorigenesis. In the light of emerging role of noncoding RNAs in cancer biology including CaP, future investigations of 6qTSG11 locus is warranted.
DNA and Cell Biology 12/2006; 25(11):597-607. · 2.07 Impact Factor
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K Sree Kumar,
Mythili Raghavan,
Kevin Hieber,
Christine Ege,
Steven Mog,
Nannette Parra,
Annette Hildabrand,
Vijay Singh,
V Srinivasan,
Raymond Toles,
Patience Karikari, Gyorgy Petrovics,
Thomas Seed,
Shiv Srivastava,
Andreas Papas
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ABSTRACT: Gamma-tocotrienol (GT) is a member of the vitamin E family. Our preliminary studies indicated that it protected mice from lethal irradiation, so we hypothesized that GT might be a radiation sensitizing agent for tumors. To test this, we induced prostate tumors by injecting PC3 cells into nude BALB/c mice. When the tumors were about 5 mm in diameter, mice were injected subcutaneously with 400 mg/kg gamma-tocotrienol and irradiated 24 h later at the site of the tumor with a dose of 12 Gy (60)Cobalt. Tumor size was monitored for 24 days after radiation. Tumor tissues as well as normal tissues like rectum, kidney, and liver were monitored for lipid peroxidation on day 4 and day 24 after radiation. The results indicated that the size of the tumors was reduced by almost 40%, but only in GT-treated and irradiated mice. In unstimulated and Fe-stimulated lipid peroxidation groups, lipid peroxidation in the tumors from irradiated mice increased to 135% and 150%, respectively, four days after irradiation and 33% and 66% in the same groups, respectively, 24 days after irradiation. In general, lipid peroxidation in the rectum did not increase in GT-treated and irradiated mice, although there was a slight increase in Fe-stimulated lipid peroxidation (29%) four days after irradiation. Unexpectedly, the kidneys were as equally sensitized to lipid peroxidation as the tumors. Liver tissue was protected in the short-term from radiation-induced lipid peroxidation. These studies indicate that the radiotherapy efficacy of prostate cancer can be increased with GT and a pro-oxidant if the kidneys can be shielded.
Life Sciences 04/2006; 78(18):2099-104. · 2.53 Impact Factor
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ABSTRACT: PCGEM1 is a prostate tissue-specific, and prostate cancer-associated noncoding RNA (ncRNA) gene. Previous results revealed a significant association of elevated PCGEM1 expression levels in prostate cancer cells of African-American patients, whose mortality rate is the highest among prostate cancer patients. Functional study of PCGEM1 demonstrated a marked increase in colony formation in LNCaP prostate cancer cells and NIH3T3 mouse fibroblast cells. This study demonstrates that PCGEM1 overexpression in LNCaP cell culture model results in the inhibition of apoptosis induced by doxorubicin (DOX). Induction of p53 and p21(Waf1/Cip1) by DOX were delayed in LNCaP cells stably overexpressing PCGEM1 (LNCaP-PCGEM1 cells) compared to control LNCaP cells. The protein levels of cleaved caspase 7, and cleaved PARP were attenuated in DOXtreated LNCaP-PCGEM1 cells compared to control LNCaP cells. Similar results were observed in LNCaP cells transiently overexpressing PCGEM1. The inhibition of PARP cleavage by PCGEM1 overexpression was also observed in LNCaP-PCGEM1 cells incubated with etoposide and sodium selenite. Fluorescence-Activated Cell Sorter Annexin-V analysis revealed significantly lower percentage of apoptotic cells in DOX-treated LNCaP-PCGEM1 cells compared to control LNCaP cells. The attenuation of apoptic response appears to be androgen dependent in this experimental model, as androgen-independent variants of LNCaP cells did not exhibit this response. In summary, this study provides new insights into cell biologic functions and novel features of an ncRNA. Further, these data unravel biological mechanisms of cell growth/cell survival-associated functions of this ncRNA in a widely used prostate cancer cell culture model.
DNA and Cell Biology 04/2006; 25(3):135-41. · 2.07 Impact Factor
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ABSTRACT: Changes in transcriptional regulation can be permissive for tumor progression by allowing for selective growth advantage of tumor cells. Tumor suppressors can effectively inhibit this process. The PMEPA1 gene, a potent inhibitor of prostate cancer cell growth is an androgen-regulated gene. We addressed the question of whether or not androgen receptor can directly bind to specific PMEPA1 promoter upstream sequences. To test this hypothesis we extended in silico prediction of androgen receptor binding sites by a modeling approach and verified the actual binding by in vivo chromatin immunoprecipitation assay. Promoter upstream sequences of highly androgen-inducible genes were examined from microarray data of prostate cancer cells for transcription factor binding sites (TFBSs). Results were analyzed to formulate a model for the description of specific androgen receptor binding site context in these sequences. In silico analysis and subsequent experimental verification of the selected sequences suggested that a model that combined a GREF and a GATA TFBS was sufficient for predicting a class of functional androgen receptor binding sites. The GREF matrix family represents androgen receptor, glucocorticoid receptor and progesterone receptor binding sites and the GATA matrix family represents GATA binding protein 1-6 binding sites. We assessed the regulatory sequences of the PMEPA1 gene by comparing our model-based GREF_GATA predictions to weight matrix-based predictions. Androgen receptor binding to predicted promoter upstream sequences of the PMEPA1 gene was confirmed by chromatin immunoprecipitation assay. Our results suggested that androgen receptor binding to cognate elements was consistent with the GREF_GATA model. In contrast, using only single GREF weight matrices resulted in additional matches, apparently false positives. Our findings indicate that complex models based on datasets selected by biological function can be superior predictors as they recognize TFBSs in their functional context.
Journal of Molecular Biology 12/2005; 353(4):763-71. · 4.00 Impact Factor
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Gyorgy Petrovics,
Aijun Liu,
Syed Shaheduzzaman,
Bungo Furusato,
Bungo Furasato,
Chen Sun,
Yongmei Chen,
Martin Nau,
Lakshmi Ravindranath,
Yidong Chen,
Albert Dobi,
Vasantha Srikantan,
Isabell A Sesterhenn,
David G McLeod,
Maryanne Vahey,
Judd W Moul,
Shiv Srivastava
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ABSTRACT: Transcription factors encoded by the ETS family of genes are central in integrating signals that regulate cell growth and differentiation, stress responses, and tumorigenesis. This study, analysing laser microdissected paired benign and malignant prostate epithelial cells from prostate cancer (CaP) patients (n=114; 228 specimen) by GeneChip and quantitative real-time RT-PCR, identifies ETS-related gene (ERG), a member of the ETS transcription factor family, as the most frequently overexpressed proto-oncogene in the transcriptome of malignant prostate epithelial cells. Combined quantitative expression analysis of ERG with two other genes commonly overexpressed in CaP, AMACR and DD3, revealed overexpression of at least one of these three genes in virtually all CaP specimen (54 of 55). Comprehensive evaluation of quantitative ERG1 expression with clinicopathological features also suggested that ERG1 expression level in prostate tumor cells relative to benign epithelial cells is indicator of disease-free survival after radical prostatectomy.
Oncogene 06/2005; 24(23):3847-52. · 6.37 Impact Factor
