High Gleason Grade Prostate Cancer Research Articles

Abstract 2270: Hyperlipidemia promotes aggressive variant prostate cancer via RNA-binding protein Quaking

Abstract Introduction: Hyperlipidemia has been associated with increased risk of advanced stage and high Gleason grade prostate cancer (PCa), yet the underlying mechanism is not completely understood. Quaking (QKI) is an RNA-binding protein (RBP) that regulate lipid metabolism. For PCa, QKI overexpression has been associated with increased chance of metastatic recurrence. Method: We performed RNA sequencing of prostate cancer tissues of hyperlipidemia (n = 12) and normolipidemia (n=32). Tissue samples were acquired by MRI-US fusion targeted biopsy. DESeq2 and GSEA was used to identify differently expressed genes and enriched genesets. A web-based RBP motif screening tool TRANSITE was utilized to identify active RBPs in hyperlipidemia-associated PCa. Results: PCa samples of hyperlipidemia patients exhibited poorer histology than normolipidemia PCA. RNA sequencing found that hyperlipidemia-associated PCa is enriched of Myc-regulated genes as well as interferon or innate immunity-associated genes. Interestingly, hyperlipidemia-associated PCa gene expression signature identified PCa samples devoid of common PCa genetic alterations - TMPRSS2-ERG fusion and PTEN deletion/mutation. RBP motif screening found QKI as one of the top enriched RBP in hyperlipidemia-associated PCa transcriptome. In a separate a consecutive radical prostatectomy series (n=190), we found that QKI-high (immunohistochemistry staining score 2-3) tumors had significantly higher serum cholesterol than QKI-low (score 0-1) tumors. Overexpression and knockdown experiments proved that QKI is responsible of rapid cell proliferation and interferon-related inflammatory gene expressions, In silico analysis predicted QKI overexpressing cancer cells are susceptive to stain-mediated ferroptosis-like cell death. Mechanistically, QKI regulates expression of acyl-CoA synthetase long-chain family member 4 (ACSL4), which dictates the sensitivity of QKI overexpressing cells to ferroptosis. Conclusion: Hyperlipidemia was associated with aggressive pathologic characteristics of PCa without TMPRSS2-ERG fusion or PTEN deletion/mutation, and high tissue expression of QKI, an RNA-binding protein. QKI overexpression in PCa increased sensitivity to ACSL4-mediated ferroptosis by statins. This explains the epidemiological associations between hyperlipidemia and PCa, and will guide molecular subtype-driven drug repurposing studies. Citation Format: Hyun Ho Han, Jin Sol Sung, Dong Wook Song, Cheol Keun Park, Nam Hoon Cho, Young Deuk Choi, Woo Jin Ko. Hyperlipidemia promotes aggressive variant prostate cancer via RNA-binding protein Quaking [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2270.

Retraction Note to: Loss of PDEF, a prostate-derived Ets factor is associated with aggressive phenotype of prostate cancer: Regulation of MMP 9 by PDEF

Prostate-derived Ets factor (PDEF) is expressed in tissues of high epithelial content including prostate, although its precise function has not been fully established. Conventional therapies produce a high rate of cure for patients with localized prostate cancer, but there is, at present, no effective treatment for intervention in metastatic prostate cancer. These facts underline the need to develop new approaches for early diagnosis of aggressive prostate cancer patients, and mechanism based anti-metastasis therapies that will improve the outlook for hormone-refractory prostate cancer. In this study we evaluated role of prostate-derived Ets factor (PDEF) in prostate cancer. We observed decreased PDEF expression in prostate cancer cell lines correlated with increased aggressive phenotype, and complete loss of PDEF protein in metastatic prostate cancer cell lines. Loss of PDEF expression was confirmed in high Gleason Grade prostate cancer samples by immuno-histochemical methods. Reintroduction of PDEF profoundly affected cell behavior leading to less invasive phenotypes in three dimensional cultures. In addition, PDEF expressing cells had altered cell morphology, decreased FAK phosphorylation and decreased colony formation, cell migration, and cellular invasiveness. In contrast PDEF knockdown resulted in increased migration and invasion as well as clonogenic activity. Our results also demonstrated that PDEF downregulated MMP9 promoter activity, suppressed MMP9 mRNA expression, and resulted in loss of MMP9 activity in prostate cancer cells. These results suggested that loss of PDEF might be associated with increased MMP9 expression and activity in aggressive prostate cancer. To confirm results we investigated MMP9 expression in clinical samples of prostate cancer. Results of these studies show increased MMP9 expression correlated with advanced Gleason grade. Taken together our results demonstrate decreased PDEF expression and increased MMP9 expression during the transition to aggressive prostate cancer. These studies demonstrate for the first time negative regulation of MMP9 expression by PDEF, and that PDEF expression was lost in aggressive prostate cancer and was inversely associated with MMP9 expression in clinical samples of prostate cancer. Based on these exciting results, we propose that loss of PDEF along with increased MMP9 expression should serve as novel markers for early detection of aggressive prostate cancer.

V-ATPase-associated prorenin receptor is upregulated in prostate cancer after PTEN loss.

Phosphatase and tensin homolog (PTEN) tumor suppressor protein loss is common in prostate cancer (PCa). PTEN loss increases PI3K/Akt signaling, which promotes cell growth and survival. To find secreted biomarkers of PTEN loss, a proteomic screen was used to compare secretomes of cells with and without PTEN expression. We showed that PTEN downregulates Prorenin Receptor (PRR) expression and secretion of soluble Prorenin Receptor (sPRR) in PCa cells and in mouse. PRR is an accessory protein required for assembly of the vacuolar ATPase (V-ATPase) complex. V-ATPase is required for lysosomal acidification, amino acid sensing, efficient mechanistic target of Rapamycin complex 1 (mTORC1) activation, and β-Catenin signaling. On PCa tissue microarrays, PRR expression displayed a positive correlation with Akt phosphorylation. Moreover, PRR expression was required for proliferation of PCa cells by maintaining V-ATPase function. Further, we provided evidence for a potential clinical role for PRR expression and sPRR concentration in differentiating low from high Gleason grade PCa. Overall, the current study unveils a mechanism by which PTEN can inhibit tumor growth. Lower levels of PRR result in attenuated V-ATPase activity and reduced PCa cell proliferation.

MicroRNA‑198 suppresses prostate tumorigenesis by targeting MIB1

MicroRNAs are small non-coding RNA molecules which act as modulators of gene function, and have been identified as playing important roles in cancer as both tumor suppressors and oncogenes. The present study aimed to examine the role of miR-198 in prostate cancer aggression by analyzing how it influences several hallmarks of cancer. Abundance of miR-198 in prostate cancer and association with clinical characteristics was analyzed using a CPC-Gene prostate cancer dataset. Overexpression of miR-198 was performed using transient transfection of miR-198 mimic prior to assaying proliferation, cell cycle, and colony formation in LNCaP and DU145 cell lines using standard protocols. In vivo tumor formation in athymic nude mice was examined using LNCaP xenografts with stable overexpression conferred using lentiviral miR-198 transduction. Protein and mRNA abundance of MIB1 was determined using western blotting and RT-qPCR respectively, while miR-198 binding to MIB1 was validated using a luciferase reporter assay. miR-198 abundance was lower in high Gleason grade prostate cancer relative to intermediate and low-grade cancer. Overexpression of miR-198 diminished proliferation of prostate cancer cell lines, increased G0/G1 cell cycle arrest, and significantly impaired colony formation. Elevated miR-198 abundance was also demonstrated to impair tumor formation in vivo using LNCaP xenografts. Mindbomb E3 ubiquitin protein ligase 1 (MIB1) was demonstrated to be directly targeted by miR-198, and knockdown of MIB1 recapitulated the effects of miR-198 on proliferation and colony formation. The present evidence supports miR-198 as an important tumor suppressor in prostate cancer, and demonstrates for the first time that it acts by targeting MIB1. The present study reinforces the importance and complexity of miRNA in regulating prostate cancer aggression.

Syntaphilin Is a Novel Biphasic Biomarker of Aggressive Prostate Cancer and a Metastasis Predictor

Easily accessible biomarkers that may inform on the metastatic potential of localized prostate cancer are urgently needed. Herein, we show that syntaphilin (SNPH), a molecule originally identified as a negative regulator of mitochondrial dynamics in neurons, is abundantly expressed in prostate cancer. SNPH distribution in prostate cancer is spatially biphasic, with high expression at the invasive front, correlating with increased proliferative rates, as determined by Ki-67 labeling, and reduced levels in the central tumor bulk, which are further decreased in patients with distant metastases. Higher levels of SNPH are observed with increasing Gleason grade. Prostate tumors predominantly express a novel, extraneuronal isoform of SNPH that accumulates in mitochondria and maintains oxidative metabolism and tumor cell proliferation. These data suggest that SNPH is a novel marker of high Gleason grade prostate cancer, differentially expressed at the invasive front compared with the central tumor bulk, and is potentially down-regulated in metastatic disease. This biphasic pattern of expression may reflect a dual function of SNPH in controlling the balance between cell proliferation and invasion in tumors.

The Role of BRCA Testing in Hereditary Pancreatic and Prostate Cancer Families.

Beyond breast and ovarian cancers, mutations in the BRCA1 and BRCA2 genes increase risks for pancreatic and prostate cancers and contribute to the prevalence of these cancers. Mutations in a number of other genes have also been shown to increase the risk for these cancers as well. Genetic testing is playing an increasingly important role in the treatment of patients with pancreatic and prostate cancer and is now recommended for all patients with pancreatic or metastatic prostate cancer, as well as patients with high Gleason grade prostate cancer and a remarkable family history. Identification of an inherited mutation can direct evaluation of the patient for other cancer risks as well as identification and management of disease in at-risk relatives. Growing evidence suggests improved responses to PARP inhibitors and other therapies in patients with mutations in the BRCA and other DNA repair genes. Although more work must be done to clarify the prevalence and penetrance of mutations in genes other than BRCA1 and BRCA2 in patients with pancreatic and prostate cancer, in most cases, testing is now being done with a panel of multiple genes. Because of the complexities in panel testing and the increased likelihood of finding variants of uncertain significance, pre- and post-test genetic counseling are essential.

Prostate-only Versus Whole-pelvis Radiation with or Without a Brachytherapy Boost for Gleason Grade Group 5 Prostate Cancer: A Retrospective Analysis

BackgroundThe role of elective whole-pelvis radiotherapy (WPRT) remains controversial. Few studies have investigated it in Gleason grade group (GG) 5 prostate cancer (PCa), known to have a high risk of nodal metastases. ObjectiveTo assess the impact of WPRT on patients with GG 5 PCa treated with external-beam radiotherapy (EBRT) or EBRT with a brachytherapy boost (EBRT+BT). Design, setting, and participantsWe identified 1170 patients with biopsy-proven GG 5 PCa from 11 centers in the United States and one in Norway treated between 2000 and 2013 (734 with EBRT and 436 with EBRT+BT). Outcome measurements and statistical analysisBiochemical recurrence-free survival (bRFS), distant metastasis-free survival (DMFS), and prostate cancer-specific survival (PCSS) were compared using Cox proportional hazards models with propensity score adjustment. Results and limitationsA total of 299 EBRT patients (41%) and 320 EBRT+BT patients (73%) received WPRT. The adjusted 5-yr bRFS rates with WPRT in the EBRT and EBRT+BT groups were 66% and 88%, respectively. Without WPRT, these rates for the EBRT and EBRT+BT groups were 58% and 78%, respectively. The median follow-up was 5.6yr. WPRT was associated with improved bRFS among patients treated with EBRT+BT (hazard ratio [HR] 0.5, 95% confidence interval [CI] 0.2–0.9, p=0.02), but no evidence for improvement was found in those treated with EBRT (HR 0.8, 95% CI 0.6–1.2, p=0.4). WPRT was not significantly associated with improved DMFS or PCSS in the EBRT group (HR 1.1, 95% CI 0.7–1.7, p=0.8 for DMFS and HR 0.7, 95% CI 0.4–1.1, p=0.1 for PCSS), or in the EBRT+BT group (HR 0.6, 95% CI 0.3–1.4, p=0.2 for DMFS and HR 0.5 95% CI 0.2–1.2, p=0.1 for PCSS). ConclusionsWPRT was not associated with improved PCSS or DMFS in patients with GG 5 PCa who received either EBRT or EBRT+BT. However, WPRT was associated with a significant improvement in bRFS among patients receiving EBRT+BT. Strategies to optimize WPRT, potentially with the use of advanced imaging techniques to identify occult nodal disease, are warranted. Patient summaryWhen men with a high Gleason grade prostate cancer receive radiation with external radiation and brachytherapy, the addition of radiation to the pelvis results in a longer duration of prostate-specific antigen control. However, we did not find a difference in their survival from prostate cancer or in their survival without metastatic disease. We also did not find a benefit for radiation to the pelvis in men who received radiation without brachytherapy.

ETS-related gene (ERG) expression as a predictor of oncological outcomes in patients with high-grade prostate cancer treated with primary androgen deprivation therapy: a cohort study

ObjectivesTo determine whether ETS-related gene (ERG) expression can be used as a biomarker to predict biochemical recurrence and prostate cancer-specific death in patients with high Gleason grade prostate cancer treated...

Performance of Diffusion Kurtosis Imaging Versus Diffusion Tensor Imaging in Discriminating Between Benign Tissue, Low and High Gleason Grade Prostate Cancer

To investigate the performance of diffusion kurtosis imaging (DKI) and diffusion tensor imaging (DTI) in discriminating benign tissue, low- and high-grade prostate adenocarcinoma (PCa). Forty-eight patients with biopsy-proven PCa of different Gleason grade (GG), who provided written informed consent, were enrolled. All subjects underwent 3T DWI examinations by using b values 0, 500, 1000, 1500, 2000, and 2500 s/mm2 and six gradient directions. Mean diffusivity, fractional anisotropy (FA), apparent kurtosis (K), apparent kurtosis-derived diffusivity (D), and proxy fractional kurtosis anisotropy (KFA) maps were obtained. Regions of interest were selected in PCa, in the contralateral benign zone, and in the peritumoral area. Histogram analysis was performed by measuring mean, 10th, 25th, and 90th (p90) percentile of the whole-lesion volume. Kruskal-Wallis test with Bonferroni correction was used to assess significant differences between different regions of interest. The correlation between diffusion metrics and GG and between DKI and DTI parameters was evaluated with Pearson's test. ROC curve analysis was carried out to analyze the ability of histogram variables to differentiate low- and high-GG PCa. All metrics significantly discriminated PCa from benign and from peritumoral tissue (except for K, KFAp90, and FA). Kp90 showed the highest correlation with GG and the best diagnostic ability (area under the curve = 0.84) in discriminating low- from high-risk PCa. Compared to DTI, DKI provides complementary and additional information about prostate cancer tissue, resulting more sensitive to PCa-derived modifications and more accurate in discriminating low- and high-risk PCa.

Abstract B11: Proteomic analysis of serum-derived exosomes: Identification of novel protein signature associated with African-American prostate cancer

Abstract African-American men face a stark prostate cancer (PCA)-related health disparity in the United States, with the highest incidence and mortality rate compared to all other races. African-American men are more frequently diagnosed with high Gleason grade PCA at a younger age and with a poorer prognosis. In the past three decades, there has been little improvement in reducing this health disparity, demanding additional and innovative measures. Here, we focused on the identification of novel serum exosome-based ‘protein signature' for potential use in the early detection and better prognosis of PCA in African-American men. Analysis of clinical serum samples showed that compared to healthy individuals, exosome concentration was increased by ~3.2 fold (p=0.047) in the sera of African-American men with PCA (Gleason score 7). Mass spectrometry based proteomic analysis of serum exosomal proteins showed 55 common proteins in African-American men with PCA (PAA) and normal African-American men without PCA (NAA). Interestingly, 7 unique proteins [Isoform 2 of Coiled-coil and C2 domain-containing protein 1A, Keratin type I cytoskeletal 10, UPF0728 protein C10orf53, DnaJ homolog subfamily C member 13, Prothrombin, Apolipoprotein(a) and Coiled-coil domain-containing protein 172] were present only in PAA, and not in NAA. The top upregulated proteins in PAA, as compared to NAA, included Keratin type II cytoskeletal 2 epidermal (64 fold), Serum amyloid P-component (39 fold), Keratin type II cytoskeletal 1 (13 fold), Keratin type I cytoskeletal 9 (12 fold), Isoform 2 of Filamin-A (2.6 fold), Isoform 3 of Vitamin D-binding protein (2.4 fold), Ig kappa chain V-II region Cum (2.4 fold) and Isoform 2 of Eukaryotic translation initiation factor 2-alpha kinase 4 (1.8 fold). The top downregulated proteins in PAA included Apolipoprotein A-I (0.04 fold), Complement component C8 alpha chain (0.07 fold), Plasminogen (0.08 fold), Complement component C7 (0.1 fold), and Isoform 2 of Inter-alpha-trypsin inhibitor heavy chain H4 (0.2 fold). Importantly, Ingenuity pathway analysis (IPA) showed that the proteins detected by proteomic analysis in PAA exosomes belonged to the acute-phase response signaling pathway proteins, which have been reported for their potential use as diagnostic biomarkers for PCA. Next, we compared proteins loaded in PAA serum exosomes with Gleason score-matched Caucasian PCA (PCC) serum exosomes. PAA and PCC exosomes shared 57 common proteins, while PAA serum exosomes showed six unique proteins (Isoform 2 of Coiled-coil and C2 domain-containing protein 1A, UPF0728 protein C10orf53, Ig kappa chain V-I region EU, Ig kappa chain V-II region Cum, DnaJ homolog subfamily C member 13, Coiled-coil domain-containing protein 172). Furthermore, top upregulated proteins in PAA, as compared to PCC, included Isoform 2 of Eukaryotic translation initiation factor 2-alpha kinase 4 (34 fold), Keratin type I cytoskeletal 10 (10 fold), SCO-spondin (5.3 fold), Serum amyloid P-component (4 folds) and Apolipoprotein(a) (3.9 fold). The top down regulated proteins in PAA, as compared to PCC, included Ig lambda chain V-I region WAH (0.02 fold), alpha-1B-glycoprotein (0.03 fold), Apolipoprotein A-I (0.03 fold), Complement component C8 alpha chain (0.06 fold) and Isoform 2 of Haptoglobin (0.09 fold). Overall, we have identified several unique and differentially expressed proteins in the serum exosomes of African-American men with PCA. These results also support further development and application of serum exosome-based proteomic signature for early detection and better prognosis of PCA in African- American men. Citation Format: Gagan Deep, Gatikrushna Panigrahi, Rakesh Singh, Kathleen Torkko, Adrie Bokhoven. Proteomic analysis of serum-derived exosomes: Identification of novel protein signature associated with African-American prostate cancer. [abstract]. In: Proceedings of the Ninth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2016 Sep 25-28; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(2 Suppl):Abstract nr B11.

The Dark Side of 5α-Reductase Inhibitors' Therapy: Sexual Dysfunction, High Gleason Grade Prostate Cancer and Depression

With aging, abnormal benign growth of the prostate results in benign prostate hyperplasia (BPH) with concomitant lower urinary tract symptoms (LUTS). Because the prostate is an androgen target tissue, and transforms testosterone into 5α-dihydrotestosterone (5α-DHT), a potent androgen, via 5α-reductase (5α-R) activity, inhibiting this key metabolic reaction was identified as a target for drug development to treat symptoms of BPH. Two drugs, namely finasteride and dutasteride were developed as specific 5α-reductase inhibitors (5α-RIs) and were approved by the U.S. Food and Drug Administration for the treatment of BPH symptoms. These agents have proven useful in the reducing urinary retention and minimizing surgical intervention in patients with BPH symptoms and considerable literature exists describing the benefits of these agents. In this review we highlight the adverse side effects of 5α-RIs on sexual function, high grade prostate cancer incidence, central nervous system function and on depression. 5α-Rs isoforms (types 1-3) are widely distributed in many tissues including the central nervous system and inhibition of these enzymes results in blockade of synthesis of several key hormones and neuro-active steroids leading to a host of adverse effects, including loss of or reduced libido, erectile dysfunction, orgasmic dysfunction, increased high Gleason grade prostate cancer, observed heart failure and cardiovascular events in clinical trials, and depression. Considerable evidence exists from preclinical and clinical studies, which point to significant and serious adverse effects of 5α-RIs, finasteride and dutasteride, on sexual health, vascular health, psychological health and the overall quality of life. Physicians need to be aware of such potential adverse effects and communicate such information to their patients prior to commencing 5α-RIs therapy.

Soluble interleukin-6 receptor to interleukin-6 (sIL‑6R/IL-6) ratio in serum as a predictor of high Gleason sum at radical prostatectomy

Approximately 40% of males with low Gleason grade clinically localized prostate cancer (PCa) at biopsy were finally diagnosed with high Gleason grade PCa at radical prostatectomy (RP). Therefore, a more reliable assessment of the Gleason grade prior to RP is required. Readily available modalities such as circulating biomarkers may be useful for this purpose. The aim of this study was to evaluate the ability of preoperative interleukin 6 (IL‑6) and its soluble receptor (sIL‑6R), as well as urokinase-type plasminogen activator (u-PA), its receptor (u-PAR) and the inhibitor (PAI-1) to predict Gleason score upgrading. A total of 51 PCa patients with biopsy Gleason score ≤7 were studied. IL‑6 and sIL‑6R, uPA, uPAR and PAI-1 preoperative serum levels were determined. Differences in the median and mean values of the preoperative blood levels of all biomarkers between patients with and without Gleason score upgrading were tested. The prognostic performance of each biomarker was further assessed by means of receiver operating characteristic (ROC) curves. The results showed the sIL‑6R and sIL‑6R/IL-6 ratio median levels to be significantly higher in patients who had Gleason score upgrading from ≤7 at biopsy to >7 at RP (p=0.024 and p=0.011, respectively). The ROC curve revealed that sIL‑6R and the sIL‑6R/IL‑6 ratio identified subjects at a high risk of upgrading [area under curve (AUC)=0.80 and AUC=0.83, respectively] with similar sensitivity and higher specificity for the ratio. The findings suggest that preoperative sIL‑6R and sIL‑6R/IL‑6 ratio determination in serum are useful as prognostic biomarkers in PCa patients.

RETRACTED ARTICLE: Loss of PDEF, a prostate-derived Ets factor is associated with aggressive phenotype of prostate cancer: Regulation of MMP 9 by PDEF

BackgroundProstate-derived Ets factor (PDEF) is expressed in tissues of high epithelial content including prostate, although its precise function has not been fully established. Conventional therapies produce a high rate of cure for patients with localized prostate cancer, but there is, at present, no effective treatment for intervention in metastatic prostate cancer. These facts underline the need to develop new approaches for early diagnosis of aggressive prostate cancer patients, and mechanism based anti-metastasis therapies that will improve the outlook for hormone-refractory prostate cancer. In this study we evaluated role of prostate-derived Ets factor (PDEF) in prostate cancer.ResultsWe observed decreased PDEF expression in prostate cancer cell lines correlated with increased aggressive phenotype, and complete loss of PDEF protein in metastatic prostate cancer cell lines. Loss of PDEF expression was confirmed in high Gleason Grade prostate cancer samples by immuno-histochemical methods. Reintroduction of PDEF profoundly affected cell behavior leading to less invasive phenotypes in three dimensional cultures. In addition, PDEF expressing cells had altered cell morphology, decreased FAK phosphorylation and decreased colony formation, cell migration, and cellular invasiveness. In contrast PDEF knockdown resulted in increased migration and invasion as well as clonogenic activity. Our results also demonstrated that PDEF downregulated MMP9 promoter activity, suppressed MMP9 mRNA expression, and resulted in loss of MMP9 activity in prostate cancer cells. These results suggested that loss of PDEF might be associated with increased MMP9 expression and activity in aggressive prostate cancer. To confirm results we investigated MMP9 expression in clinical samples of prostate cancer. Results of these studies show increased MMP9 expression correlated with advanced Gleason grade. Taken together our results demonstrate decreased PDEF expression and increased MMP9 expression during the transition to aggressive prostate cancer.ConclusionsThese studies demonstrate for the first time negative regulation of MMP9 expression by PDEF, and that PDEF expression was lost in aggressive prostate cancer and was inversely associated with MMP9 expression in clinical samples of prostate cancer. Based on these exciting results, we propose that loss of PDEF along with increased MMP9 expression should serve as novel markers for early detection of aggressive prostate cancer.

Abstract 2251: Functional significance of prostate derived ETs factor in detection of highgrade prostate cancer

Abstract INTRODUCTION AND OBJECTIVES: Conventional therapies produce a high rate of cure for patients with localized prostate cancer, but there is, at present, no effective treatment for intervention in metastatic prostate cancer. These facts underline the need to develop new approaches for early diagnosis of aggressive prostate cancer patients, and mechanism based anti-metastasis therapies that will improve the outlook for hormone-refractory prostate cancer. In this study we evaluated role of prostate-derived Ets factor (PDEF) in prostate cancer. METHODS: PDEF and MMP9 expression was assayed by Immuno-histochemical methods in Prostate Cancer tissue microarrays. PDEF expression in cell lines was investigated using Western Blot analysis. We constructed cells with stable expression of PDEF using a retroviral vector or knocked down PDEF in cells using PDEF specific SiRNA. Cell migration, invasion and clonogenic activity were monitored using scratch assays, Matrigel invasion assays and growth in soft agar respectively. RESULTS: We observed decrease of PDEF expression in prostate cancer cell lines correlated with increased aggressive phenotype, and complete loss of PDEF protein in metastatic prostate cancer cell lines. Loss of PDEF expression was confirmed in high Gleason Grade prostate cancer samples by immunohistochemical methods. Our results also demonstrated that PDEF down regulated MMP-9 promoter activity, suppressed MMP9 mRNA expression, and resulted in loss of MMP9 activity in prostate cancer cells. These results suggested that loss of PDEF might be associated with increased MMP9 expression and activity in aggressive prostate cancer. To confirm results we investigated MMP9 expression in clinical samples of prostate cancer. Results of these studies show increased MMP9 expression correlated with advanced Gleason grade. Taken together our results demonstrate that decreased PDEF expression and increased MMP-9 expression during the transition to aggressive prostate cancer. CONCLUSIONS: These studies demonstrate for the first time negative regulation of MMP9 expression by PDEF, that PDEF expression was lost in aggressive prostate cancer and was inversely associated with MMP-9 expression in clinical samples of prostate cancer. Based on these exciting results we propose that loss of PDEF along with increased MMP9 expression should serve as novel markers for early detection of aggressive prostate cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2251.

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N-cadherin switching occurs in high Gleason grade prostate cancer

The inappropriate expression of non-epithelial N-(neural) cadherin by epithelial cells, called cadherin switching, has been suggested to play a role in prostate cancer (PC) progression. We explored the role of N-cadherin as a biomarker in PC by correlating the expression with clinical parameters. Two pathologists blinded to patients' history independently reviewed and scored the intensity and extent of staining of N-cadherin expression in 44 randomly selected radical prostatectomy specimens. The expression was correlated with total Gleason grade, individual Gleason patterns, tumor stage, and preoperative serum prostate specific antigen (PSA) levels and P-values < 0.05 were considered statistically significant. Of the 44 PC specimens, 14 (32%), 23 (52%), 7 (16%) consisted of Gleason grade 5-6, 7, and 8-10, respectively and 20/44 (45%) demonstrated N-cadherin expression. N-cadherin was expressed in 1/14 (7%) of Gleason 5-6 compared to 15/23 (65%) of Gleason grade 7, and 4/7 (57%) of Gleason grade 8-10, demonstrating a significant correlation between N-cadherin switching and higher Gleason grade (P = 0.001). While only about a third of primary or secondary Gleason pattern 3 demonstrated N-cadherin expression, a majority of Gleason patterns of > or = 4 expressed N-cadherin (P > 0.05), further suggesting that N-cadherin switching occurs with higher Gleason pattern. However, N-cadherin expression did not significantly correlate with preoperative serum PSA levels or tumor stage in our study cohort. We have demonstrated for the first time that N-cadherin switching occurs in higher grade PC and correlates significantly with increasing Gleason patterns. N-cadherin may be as a useful biomarker of aggressive PC.

Phosphorylation of Akt (Ser473) is an excellent predictor of poor clinical outcome in prostate cancer.

We previously showed, by immunohistochemistry with phospho-specific antibodies, increased phosphorylation (activation) of Akt (Ser(473)) [phosphorylated Akt (pAkt)] in high-Gleason grade prostate cancer (Malik SN, et al., Clin Cancer Res 2002;8:1168-71). Elevation of pAkt was accompanied by decreased phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 (Thr(202)/Tyr(204)) [phosphorylated ERK (pERK)], indicative of inactivation. In this report, we determined whether increased pAkt and decreased pERK predicted clinical outcome. Prostate-specific antigen (PSA) failure (detectable and rising PSA) versus PSA non-failure (undetectable PSA 5 years after prostatectomy) was used as a surrogate for clinical outcome. Prostate tumors from cases of PSA failure versus non-failure were stained for pAkt and pERK. A significant increase in mean pAkt staining (P < 0.001) in the PSA failures versus non-failures was seen based on the Wilcoxon signed ranks test [222.18 +/- 33.9 (n = 37) versus 108.79 +/- 104.57 (n = 16)]. Using the best-fitting multiple logistic regression equation, a 100-point increase in pAkt staining resulted in a 160% increase in the odds of being a PSA failure. There was decreased staining for pERK in PSA failures versus non-failures: a 100-point decrease resulted in an 80% increase in the odds of being a PSA failure. Each of these effects assumed the other biomarker was held constant. The area under the receiver-operating characteristic curve for these two biomarkers predicting PSA failure was 0.84, indicating excellent discrimination between PSA failure and non-failure cases. These data indicate that increased pAkt, alone or together with decreased pERK, is an important predictor of probability of PSA failure. However, pERK alone was not a significant predictor of PSA failure.

The utility of free/total PSA ratios in the detection of high gleason grade prostate cancer in a cohort of prospectively screened young men with a total PSA of 4 to 10 ng/ml

The utility of free/total PSA ratios in the detection of high gleason grade prostate cancer in a cohort of prospectively screened young men with a total PSA of 4 to 10 ng/ml

Brachytherapy for clinically localized prostate cancer

Prostate brachytherapy is an effective treatment option for clinically organ-confined prostate carcinoma. Observed 5- and 10-year follow-up have documented prostate-specific antigen (PSA) levels that were comparable to published radical prostatectomy series and were better than several published external-beam radiation series. Between January 1987 and June 1988, a total of 152 consecutive patients with Stage T1 to T3 low to high Gleason grade prostate cancer were studied at Northwest Hospital in Seattle, Washington. Patients' median age was 70 years (range, 53 to 92 years). All patients received Iodine-125 prostate brachytherapy with or without a 45 Gy dose of external-beam radiation. The average preoperative PSA, clinical stage, and prostate needle biopsy Gleason sum were 11 ng/ml, T2, and (5), respectively, and were known in all but five patients. PSA follow-up, clinical examination, and biopsy results judged disease-free survival at 5 and 10 postoperative years. Elevation of PSA above 0.5 ng/ml or a positive biopsy or a positive bone scan was considered treatment failure. The authors provide an historical review of prostate brachytherapy in conjunction with up-to-date implant techniques and long-term outcome results.