Non-cancerous Prostate Tissues Research Articles

A feasibility study of novel ultrasonic tissue characterization for prostate-cancer diagnosis: 2D spectrum analysis of in vivo data with histology as gold standard

This study demonstrates the feasibility of using a novel 2D spectrum ultrasonic tissue characterization (UTC) technique for prostate-cancer diagnosis. Normalized 2D spectra are computed by performing Fourier transforms along the range (beam) and the cross-range directions of the digital radio-frequency echo data, then dividing by a reference spectrum. This 2D spectrum method provides axial and lateral information of tissue microstructures, an improvement over the current 1D spectrum analysis which only provides axial information. A pilot study was conducted on four prostate-cancer patients who underwent radical prostatectomies. Cancerous and noncancerous regions of interest, identified through histology, were compared using four 2D spectral parameters: peak value and 3 dB width of the radially integrated spectral power (RISP), slope and intercept of the angularly integrated spectral power (AISP). For noncancerous and cancerous prostatic tissues, respectively, our investigation yielded 23 +/- 1 and 26 +/- 1 dB for peak value of RISP, 7.8 +/- 0.5 degrees and 7.6 +/- 0.6 degrees for 3 dB of RISP, -2.1 +/- 0.2 and -2.7 +/- 0.4 dB/MHz for slope of AISP, and 92 +/- 5 and 112 +/- 6 dB for intercept of AISP. Preliminary results indicated that 2D spectral UTC has the potential for identifying tumor-bearing regions within the prostate gland.

PSA after Incidental Irradiation of the Nonmalignant Prostate: Long-Term Changes

Incidental irradiation of the prostate may affect serum prostate-specific antigen (PSA). However, scarce data exist on PSA changes after irradiation of noncancerous prostatic tissue. This is an update of a study on PSA after pelvic irradiation. From 1997 to 2007, blood samples of 33 men were examined who had undergone pelvic irradiation for rectal or anal cancer. The planning target volume included the prostate in all cases. No patient had clinical evidence of prostatic disease. Radiotherapy was applied in fractions of 1.8-2 Gy up to 40-50 Gy (n = 3), 50-60 Gy (n = 21), and 60-65 Gy (n = 2). Seven patients received 5 x 5 Gy. Serum PSA was measured before, during, and after radiotherapy periodically. Median log (PSA) changes were calculated according to elapsed time from starting radiotherapy. The significance was tested with chi(2)-test. 18 patients died during follow-up. For 15 patients, long-term PSA data with a median follow-up of 9 years (2,546-3,528 days) are available. PSA levels rose during the first weeks of irradiation peaking at 2-4 weeks with a significant 2.7-fold increase (p < 0.01). 1 year after radiation therapy, PSA declined below (90%) the preirradiation level, but this difference was not significant (p = 0.36). On further follow-up PSA did not change up to 8.9 years after radiotherapy (p = 0.36). Irradiation of the prostate causes transient increase of serum PSA. By 1 year, PSA has returned near the preirradiation value and stays there for at least 9 years. A major interference with prostate cancer screening or surveillance after radiotherapy is therefore unlikely.

Rad9 Has a Functional Role in Human Prostate Carcinogenesis

Prostate cancer is currently the most common type of neoplasm found in American men, other than skin cancer, and is the second leading cause of cancer death in males. Because cell cycle checkpoint proteins stabilize the genome, the relationship of one such protein, Rad9, to prostate cancer was investigated. We found that four prostate cancer cell lines (CWR22, DU145, LNCaP, and PC-3), relative to PrEC normal prostate cells, have aberrantly high levels of Rad9 protein. The 3'-end region of intron 2 of Rad9 in DU145 cells is hypermethylated at CpG islands, and treatment with 5'-aza-2'-deoxycytidine restores near-normal levels of methylation and reduces Rad9 protein abundance. Southern blot analyses indicate that PC-3 cells contain an amplified Rad9 copy number. Therefore, we provide evidence that Rad9 levels are high in prostate cancer cells due at least in part to aberrant methylation or gene amplification. The effectiveness of small interfering RNA to lower Rad9 protein levels in CWR22, DU145, and PC-3 cells correlated with reduction of tumorigenicity in nude mice, indicating that Rad9 actively contributes to the disease. Rad9 protein levels were high in 153 of 339 human prostate tumor biopsy samples examined and detectable in only 2 of 52 noncancerous prostate tissues. There was a strong correlation between Rad9 protein abundance and cancer stage. Rad9 protein level can thus provide a biomarker for advanced prostate cancer and is causally related to the disease, suggesting the potential for developing novel diagnostic, prognostic, and therapeutic tools based on detection or manipulation of Rad9 protein abundance.

SERUM PROSTATE-SPECIFIC ANTIGEN VALUE ADJUSTED FOR NONCANCEROUS PROSTATE TISSUE VOLUME IN PATIENTS UNDERGOING RADICAL PROSTATECTOMY: A NEW PREDICTOR OF BIOCHEMICAL RECURRENCE IN LOCALISED OR LOCALLY ADVANCED PROSTATE CANCER

Theaimofthisstudywastoinvestigatethesignificance ofserumprostate-specific antigen(PSA)valueadjustedfortotaltumorvolume (PSA/tumor volume) and serum PSA value adjusted for non-cancerous prostate tissue volume (NCPV) (PSA/NCPV) as a predictor of pathological findings and clinical outcome after radical prostatectomy. Clinical and pathological data of 407 patients (median age: 66.5 years; range: 41.8–85.7 years) were reviewed retrospectively. The median follow-up period was 18.1 months (range: 1.0– 107.8 months). Biochemical recurrence was defined as detectable PSA levels (greater than 0.2 ng ml 21 ) and the time of biochemical recurrence was taken to be the first time PSA became detectable. In the multivariate model, PSA/NCPV was an independent predictor of extracapsular extension and positive surgical margin (P,0.05), but PSA/tumor volume was not. Kaplan–Meier curves revealed that PSA/NCPV correlated with biochemical recurrence-free survival (P,0.001; log-rank test) but PSA/tumor volume did not (P50.275; log-ranktest). PSA/NCPV wasalso a significant independent prognostic factor for biochemicalrecurrence-free survival on multivariate Cox proportional hazard analysis (P50.004, relative risk52.42). Our findings suggest that PSA/NCPV is associated independently withextracapsularextensionandsurgicalmarginstatusandmaybeanindependentprognosticvariableofPSArecurrenceafterradical prostatectomy.

Evidence for Calpain-Mediated Androgen Receptor Cleavage as a Mechanism for Androgen Independence

Prostate carcinoma is the most commonly diagnosed cancer in men and the second leading cause of death due to cancer in Western civilization. Androgen ablation therapy is effective in treating androgen-dependent tumors, but eventually, androgen-independent tumors recur and are refractory to conventional chemotherapeutics. Hence, the emergence of androgen independence is the most challenging problem in managing prostate tumors. We report a novel mechanism of androgen independence: calpain cleaves the androgen receptor (AR) into an androgen-independent isoform. In vitro and in vivo analyses show that calpain removes the COOH-terminal ligand binding domain generating a constitutively active molecule. Analysis of human prostate tumors indicates that several tumors express higher levels of this truncated AR than noncancerous prostate tissue. In transient transfection studies, the truncated AR is three to five times more potent than the full-length receptor in transactivating transcription. The androgen-independent Rv1 cells express high levels of the truncated AR, and treatment of these cells with a calpain inhibitor reduces truncated AR expression. In the absence of androgen, inhibition of calpain activity induces apoptosis. The HIV protease inhibitor amprenavir inhibits calpain activity and is also effective in inducing apoptosis in the Rv1 cell line. The cell culture studies were reproduced in a mouse xenograft model, where, in the absence of androgens, amprenavir significantly reduces tumor growth. Together, these studies indicate that calpain-dependent proteolysis of the AR may be a mechanism of androgen independence. The calpain inhibition studies suggest that inhibiting this activity may be a potential treatment for some androgen-independent prostate tumors.

The Relationship Between Serum Prostate Specific Antigen Level and Tumor Volume Persists in the Current Era

We compared the relationships of serum prostate specific antigen to tumor volume and to noncancerous prostate tissue volume using multivariate analysis in men undergoing prostatectomy during 2 periods. From our prostatectomy database we randomly selected 200 men from 1991 to 1994 (early group) and 200 from 2000 to 2003 (recent group) who underwent radical prostatectomy without neoadjuvant therapy. The variables analyzed were patient age, log prostate specific antigen, pathological stage, Gleason score, log total tumor volume and log noncancerous prostate tissue volume. Univariate correlation and multiple regression analyses were performed to assess the linearity of the relationships among the variables. There was a significant difference between the early and recent groups in age (median 64 years, IQR 58-67 vs 59, IQR 53-65; p<0.001), prostate specific antigen (8.3 ng/ml, IQR 5.7-12.5 vs 5.8, IQR 4.4-7.8; p<0.001), total tumor volume (2.0 cc, IQR 1.0-3.6 vs 1.4, IQR 0.6-2.9; p<0.001), Gleason score (7, IQR 7-8 vs 7, IQR 7-7; p<0.001) and the incidence of extraprostatic disease (39% vs 18.5%, p<0.001) but not in noncancerous prostate tissue volume (35.7 cc, IQR 28.6-46.5 vs 37.1, IQR 28.9-50.1). There was a relationship between log prostate specific antigen and log total tumor volume (r=0.486, p<0.001 and r=0.237, p<0.01), and between log prostate specific antigen and log noncancerous prostate tissue volume (r=0.179, p<0.05 and r=0.138, p=0.051) in the early and the recent groups, respectively. Multiple regression analyses revealed that log total tumor volume, log noncancerous prostate tissue volume and Gleason score were significant independent variables for predicting log prostate specific antigen in the 2 groups. In the recent group log noncancerous prostate tissue volume had the most significant association with log prostate specific antigen (p<0.001), whereas in the early group log total tumor volume had the most significant association (p<0.001). Although the relationship between serum prostate specific antigen and tumor volume decreased from early treatment years to recent years, the association remained at a significant level. In recent years noncancerous prostate tissue volume had the most significant association with prostate specific antigen.

Free PSA forms in prostatic tissue and sera of prostate cancer patients: Analysis by 2-DE and western blotting of immunopurified samples

Objective: The isoform pattern of free prostate-specific antigen (fPSA) from sera of patients with prostate cancer (PCa) and no evidence of prostate cancer (NPCa), cancerous and non-cancerous tissues and seminal plasma, have been compared, above all regarding the degree of sialylation, with the aim to show a better discrimination of PCa and NPCa. Design and methods: The samples have been immunopurified and analyzed by two dimensional gel electrophoresis and western blotting. It was investigated which patterns were obtained when looking for the fPSA and the (−5/−7)proPSA (precursor form) before and after desialylation. Results: The fPSA sialylation and the proPSA pattern in cancerous and non-cancerous prostate tissues were similar to each other and only slightly different from PCa and NPCa sera. The different fPSA isoforms observed could not be due solely to differences in the degree of sialylation, because different fPSA and (−5/−7)proPSA precursor isoforms were still present after complete desialylation. Conclusions: Although slight differences in the fPSA and (−5/−7) proPSA glycosylation and isoform pattern were observed, they were not large enough to be considered to improve PCa diagnosis.

Prostatic fatty acids and cancer recurrence after radical prostatectomy for early-stage prostate cancer

Results from some observational studies suggest that diet and energy balance influence the clinical course of early-stage prostate cancer. To evaluate possible mechanisms, we prospectively examined the relation between prostatic concentrations of fatty acids at diagnosis and cancer recurrence following primary therapy. Fatty acids were measured by capillary gas chromatography in fresh, non-cancerous prostate tissue collected from 184 men undergoing radical prostatectomy for clinically localized prostate cancer. Their association with risk of biochemical disease recurrence (a rising serum prostate-specific antigen following a disease-free [<0.1 ng/ml] interval > or =6 months) was analyzed using Cox proportional hazards models incorporating patient age, body mass index, tumor characteristics at diagnosis, and ethnicity. During an average follow-up of 48.7 months (median = 47), 14 patients experienced biochemical recurrence. Percent total polyunsaturated fatty acid and the ratio of oleic-to-stearic acid associated with risk (multivariable hazards ratio [HR] = 0.51, 95% confidence interval [CI] = 0.29 to 0.90, p = 0.021 and HR = 1.68, 95% CI = 1.21 to 2.33, p = 0.002, respectively, per 1 standard deviation increase). The results of this study are preliminary, but they suggest that pre-diagnostic prostatic concentrations of fatty acids associate with risk of biochemical recurrence following radical prostatectomy for clinically localized prostate cancer.

Multimodality tissue‐type imaging of prostate cancer

Unlike many tumors, prostate cancer cannot be imaged reliably by any single, existing, conventional modality. This makes guiding biopsies, targeting therapy, and monitoring effects problematic. Therefore, our objective is to improve significantly the depiction of prostate cancers using multimodality, multifeature techniques combined with nonlinear classifiers such as artificial neural networks (ANNs) and support vector machines (SVMs). Our previous studies show encouraging potential for tissue typing and imaging based on ultrasound spectrum analysis using ANNs and SVMs that produce ROC‐curve areas of 0.84 to 0.88 compared to 0.64 for conventional ultrasound imaging. Similar studies by others have shown that magnetic‐resonance spectroscopy can produce comparable ROC‐curve areas based on the ratio of choline and creatine to citrate. Because these two modalities sense entirely distinct properties of tissue, i.e., microscopic mechanical properties by ultrasound and chemical properties by magnetic resonance, their combination should markedly improve classification performance in distinguishing between cancerous and noncancerous prostate tissue. We have undertaken preliminary studies incorporating these two modalities. These studies demonstrate the feasibility of coregistering features from each modality and generating new, combined‐modality images that exploit the attributes of both modalities.

SR-FTIR spectroscopic preliminary findings of non-cancerous, cancerous, and hyperplastic human prostate tissues

Synchrotron radiation Fourier transform infrared (SR-FTIR) spectroscopy belongs to modern spectroscopic techniques and has been very often used to study chemical composition of different types of tissue. A microscope setup attached to the SR-FTIR spectrometer enables tissue analysis to be done at micrometer scale. Prostate diseases including hyperplasia and cancer have recently become the most common among men and therefore there is a need for continuous analysis using several supplementary analytical techniques. In the present study, prostate samples from five patients have been analyzed. The samples have been obtained from the organs removed during prostatectomy and then classified as non-cancerous, cancerous, or hyperplastic. Classification has been based on histopathological examinations. The tissue sections have been analyzed by FTIR microspectroscopy using both globar and infrared synchrotron radiation sources. In both cases, microscopic mapping of selected areas of the tissues has been performed. In order to characterize differences between sections of the tissues containing various numbers of healthy and pathological cells, changes in relative intensity of the bands in the range of 4000–2800 cm −1 have been analyzed. Maps of absorbance intensity ratios of bands due to CH 2 and CH 3 stretching vibrations (in the region from 3000 to 2800 cm −1) and those due to CH 2 and NH stretching vibrations (in the region from 3700 to 2800 cm −1) have been created in order to analyze pathological changes in tissues. This study confirms a correlation between CH 2/CH 3 and CH 2/NH absorption intensity ratios depending on the histological state of the sample.

Epigenetic Inactivation of the Dioxin-Responsive Cytochrome P4501A1 Gene in Human Prostate Cancer

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD; dioxin) is a toxic environmental contaminant that works through dioxin response elements (DRE) to activate gene expression. We tested the hypothesis that cancer-related epigenetic changes suppress dioxin activation of the cytochrome P4501A1 (CYP1A1) gene. 5-Aza-2'-deoxycytidine (5-aza-CdR), an inhibitor of DNA methylation, increases TCDD-inducible CYP1A1 mRNA expression in cancerous LNCaP cells but not in noncancerous PWR-1E and RWPE-1 cells (all human prostate cell lines). Bisulfite DNA sequencing shows that the TCDD-responsive CYP1A1 enhancer is highly methylated in LNCaP cells but not in RWPE-1 cells. In vivo footprinting experiments reveal that unmethylated DRE sites do not bind protein in response to TCDD in LNCaP cells, whereas inducible DRE occupancy occurs in RWPE-1 cells. Pretreatment of LNCaP cells with 5-aza-CdR partially restores TCDD-inducible DRE occupancy, showing that DNA methylation indirectly suppresses DRE occupancy. Chromatin immunoprecipitation experiments reveal that LNCaP cells lack trimethyl histone H3 lysine 4, a mark of active genes, on the CYP1A1 regulatory region, whereas this histone modification is prevalent in PWR-1E and RWPE-1 cells. We also analyzed CYP1A1 enhancer methylation in human prostate tissue DNA. We do not detect CYP1A1 enhancer methylation in 30 DNA samples isolated from noncancerous prostate tissue. In contrast, 11 of 30 prostate tumor DNA samples have detectable CYP1A1 enhancer methylation, indicating that it is hypermethylated in prostate tumors. This is the first report that shows that CYP1A1 is aberrantly hypermethylated in human prostate cancer and has an altered, inaccessible chromatin structure that suppresses its dioxin responsiveness.

Dealing with non-cancerous findings on prostate biopsy

Most prostate biopsies do not show malignancy. The proper management of non-cancerous pathologic findings of the prostate is controversial. For this article, we reviewed the current literature for indications for repeat prostate biopsy after initial biopsies demonstrated non-cancerous prostatic tissue or benign prostatic hyperplasia. This review includes discussions of management of asymptomatic prostatitis and how it may affect prostate-specific antigen, and also the management of several potentially premalignant lesions such as atrophy, atypical small acinar proliferation, and high-grade prostatic intraepithelial neoplasia. There is a paucity of randomized trials in this area and, considering the high number of biopsies with non-malignant findings, we conclude that more investigation is warranted in this area.

Ultrasonic and magnetic‐resonance spectra in tissue‐type imaging for planning and monitoring prostate cancer treatment

No reliable method of imaging prostate cancer currently exists. These prostate tissue‐typing studies aim to improve the effectiveness of biopsy guidance and treatment monitoring by developing better imaging methods for identifying cancerous prostate tissue. Success will reduce the false‐negative rate of biopsies and treatment side‐effects. Ultrasonic (US) radio‐frequency (rf) echo‐signal data acquired during biopsy examinations were used to compute spectral parameters. These spectral parameters along with clinical parameters, e.g., PSA, were used to train a neural network classifier using biopsy results as the gold standard. Cancer‐likelihood scores from a look‐up table were used to generate tissue‐type images (TTIs). The ROC‐curve area for US neural‐network‐based classification was 0.844±0.018 vs 0.638±0.031 for B‐mode‐based classification, and the sensitivity of neural‐network based classification was superior to that of B‐mode‐guided biopsies. These classification methods are being extended to include magnetic‐resonance spectral (MRS) techniques that use the choline to citrate ratio‐to‐distinguish cancerous from noncancerous prostate tissue. 3D renderings of prostatectomy histology, US, and MR images show encouraging correlations, and combining MRS parameters with US spectral parameters appears to have potential to further improve prostate‐cancer imaging. [Work supported in part by NIH Grant CA053561.]

Preliminary Study on Chemical Speciation of Sulphur in Cancerous Tissues

Sulphur is vital for almost all living organisms by participating in a wide variety of metabolic processes. Nevertheless its biochemistry is only partially understood, due to it a few tools such as X-ray absorption near edge structure may be used to determine its chemical speciation in biological system. In this paper we focused on analysis of composition and elemental distribution in tissue structures of biological samples. We examined cancerous and noncancerous prostate tissues. Experiments were carried out on the L-beam line at the HASYLAB, DESY (Hamburg, Germany) and DAΦNE-Light Facility DRX1 at the Laboratori Nationali di Frascati (Frascati, Italy). Synchrotron radiation induced X-ray emission measurements reveal the significant differences in concentration of sulphur between cancerous and non-cancerous tissues. X-ray absorption near edge structure spectra show two main types of sulphur that are represented by X-ray peaks at 2476 eV and 2484 eV. This suggests that different sulphur components are present in the measured samples.

Differential expression of TGFβ‐stimulated clone 22 in normal prostate and prostate cancer

The transforming growth factor-beta (TGFbeta) superfamily and its downstream effector genes are key regulators of epithelial homeostasis. Altered expression of these genes may be associated with malignant transformation of the prostate gland. The cDNA array analysis of differential expression of the TGFbeta superfamily and functionally related genes between patient-matched noncancerous prostate (NP) and prostate cancer (PC) bulk tissue specimens highlighted two genes, namely TGFbeta-stimulated clone-22 (TSC-22) and Id4. Verification of their mRNA expression by real-time PCR in patient-matched NP and PC bulk tissue, in laser-captured pure epithelial and cancer cells and in NP and PC cell lines confirmed TSC-22 underexpression, but not Id4 overexpression, in PC and in human PC cell lines. Immunohistochemical analysis showed that TSC-22 protein expression in NP is restricted to the basal cells and colocalizes with the basal cell marker cytokeratin 5. In contrast, all matched PC samples lack TSC-22 immunoreactivity. Likewise, PC cell lines do not show detectable TSC-22 protein expression as shown by immunoblotting. TSC-22 should be considered as a novel basal cell marker, potentially useful for studying lineage determination within the epithelial compartment of the prostate. Conversely, lack of TSC-22 seems to be a hallmark of malignant transformation of the prostate epithelium. Accordingly, TSC-22 immunohistochemistry may prove to be a diagnostic tool for discriminating benign lesions from malignant ones of the prostate. The suggested tumour suppressor function of TSC-22 warrants further investigation on its role in prostate carcinogenesis and on the TSC-22 pathway as a candidate therapeutic target in PC.

Iron and other elements studies in cancerous and non-cancerous prostate tissues

To understand the role of trace elements in the oxidative stress, which may be an important factor in the pathogenesis of prostate cancer, we investigated the distribution and chemical state of Fe using synchrotron radiation. Therefore, both synchrotron radiation induced X-ray emission (SRIXE) and X-ray absorption near-edge structure (XANES) techniques have been applied to study cancerous and non-cancerous prostate tissues. The results obtained in this work prove that SRIXE and XANES techniques are complementary ones for analysis of trace elements in biomedical samples. The absorption K-edge position of iron determined in cancerous tissue is shifted by 2.9 eV towards higher energies in comparison to iron absorption K-edge determined in non-cancerous tissue. The information obtained in this way may help to understand the role of oxidation state of iron in the oxidative stress underlying the oncogenesis.

Diagnostic and Prognostic Information in Prostate Cancer with the Help of a Small Set of Hypermethylated Gene Loci

Our study was designed to evaluate promoter CpG island hypermethylation in the diagnosis and prognosis of prostate cancer. Primary prostate cancers from 53 patients, pelvic lymph nodes, noncancerous prostate tissues, and prostate cell lines were analyzed. Real-time methylation-specific PCR was used to identify CpG island hypermethylation at five promising gene loci (i.e., GSTP1, APC, PTGS2, MDR1, and RASSF1a). At three gene loci (GSTP1, APC, and PTGS1) and CpG island, hypermethylation was highly prevalent in prostate cancers (71-91%), and analysis of receiver operator curves showed that hypermethylation at these three gene loci can distinguish between prostate cancer and noncancerous prostatic tissue (i.e., benign hyperplasia) with a sensitivity of 71.1% to 96.2% and a specificity of 92.9% to 100%. Using sensitive SYBR green methylation-specific PCR technology, we observed a respective 28% and 71% hypermethylation rate at the RASSF1a and MDR1 loci in benign prostate hyperplasia, which may represent early nonaggressive carcinogenesis. Methylation characteristics in prostate cancer metastases (i.e., pelvic lymph nodes) were comparable to the respective primary cancer. Statistical analysis showed no correlation between the methylation status of a single gene locus and clinicopathologic variables (e.g., preoperative prostate specific antigen levels, Gleason score, capsular penetration, involvement of seminal vesicle, and age). In contrast, the methylation of two (GSTP1/APC; GSTP1/PTGS2) or three (GSTP1/APC/PTGS2) gene loci correlated with prognostic indicators (i.e., pathologic stage, extraprostatic extension, and Gleason score, but not with prostate specific antigen levels). Our data suggest that the evaluation of DNA hypermethylation at three gene loci (i.e., GSTP1, APC, and PTGS2) is of diagnostic and prognostic value in prostate cancer.

449: Differential Gene Expression in Noncancerous Prostate Tissue of Men with and without Prostate Cancer

94 INTRODUCTION & OBJECTIVE Microarray studies have made significant contributions to the molecular classification of prostate cancer (PCA). The identification of class-specific transcriptional patterns may represent new targets for the development of new diagnostic tools and cancer therapies. We performed gene expression analysis of normal and malignant tissue samples taken from prostate cancer patients. In addition, we included normal prostate samples from an healthy control group. Our aims were to identify (1) the gene expression patterns distinguishing normal and malignant tissue and (2) the molecular signatures discriminating normal tissue from healthy males and prostate cancer patients. MATERIAL & METHODS We investigated 34 localized PCA, 34 matched normal prostate tissues from the nonmalignant region of the prostate and prostate tissue from 40 healthy male volunteers (18 - 67 y, by needle core biopsy). The samples were evaluated by histopathology. Glandular cells were isolated by laser capture microdissection and pressure catapulting (LMPC). Total RNA was isolated and quality controlled, then the RNA was amplified by T7-based RNA polymerase in vitro transcription. Gene expression profiling was performed by hybridization of the labeled samples onto human whole genome cDNA-Microarrays encompassing 37,531 cDNA clones (Human Unigene Set RZPD3.1). For following quantification we performed real-time PCR, using TaqMan probes on an ABI Prism 7000 sequence detection system (Applied Biosystems). RESULTS The analyses resulted in gene expression profiles distinguishing significantly tumor from matched normal tissue samples. Many of the genes were found deregulated in accordance with known literature data, while others had not yet been associated with prostate cancer. There was a clear gene expression pattern distinguishing normal tissue (PCA patients) from the tissue of healthy male. While the normal samples showed large molecular inter-individual variation, gene expression in the healthy samples was highly homogeneous. CONCLUSIONS We demonstrate specific gene expression differences between normal prostate tissue from PCA patients and tissue from healthy males. The identified gene expression patterns could be used for the diagnosis of prostate tumors based on the gene expression in histological non-cancerous prostate tissue.

81 Differential gene expression in noncancerous prostate tissue of men with and without prostate cancer

81 Differential gene expression in noncancerous prostate tissue of men with and without prostate cancer

Dysregulation of sterol response element-binding proteins and downstream effectors in prostate cancer during progression to androgen independence.

Androgen ablation, the most common therapeutic treatment used for advanced prostate cancer, triggers the apoptotic regression of prostate tumors. However, remissions are temporary because surviving prostate cancer cells adapt to the androgen-deprived environment and form androgen-independent (AI) tumors. We hypothesize that adaptive responses of surviving tumor cells result from dysregulated gene expression of key cell survival pathways. Therefore, we examined temporal alterations to gene expression profiles in prostate cancer during progression to androgen independence at several time points using the LNCaP xenograft tumor model. Two key genes, sterol response element-binding protein (SREBP)-1 and -2 (SREBP-1a,-1c, and -2), were consistently dysregulated. These genes are known to coordinately control the expression of the groups of enzymes responsible for lipid and cholesterol synthesis. Northern blots revealed modest increased expression of SREBP-1a, -1c, and -2 after castration, and at androgen independence (day 21-28), the expression levels of both SREBP-1a and -1c were significantly greater than precastrate levels. Changes in SREBP-1 and -2 protein expression were observed by Western analysis. SREBP-1 68-kDa protein levels were maintained throughout progression, however, SREBP-2 68-kDa protein expression increased after castration and during progression (3-fold). SREBPs are transcriptional regulators of over 20 functionally related enzymes that coordinately control the metabolic pathways of lipogenesis and cholesterol synthesis, some of which were likewise dysregulated during progression to androgen independence. RNA levels of acyl-CoA-binding protein/diazepam-binding inhibitor and fatty acid synthase decreased significantly after castration, and then, during progression, increased to levels greater than or equal to precastrate levels. Expression of farnesyl diphosphate synthase did not decrease after castration but did increase significantly during progression to androgen independence. Levels of SREBP cleavage-activating protein, a regulator of SREBP transcriptional activity, decreased after castration and increased significantly at androgen independence. In clinical prostate cancer specimens from patients with varying grades of disease, the stained tissue sections showed high levels of SREBP-1 protein compared with noncancerous prostate tissue. After hormone withdrawal therapy, tumor levels of SREBP-1 decreased significantly after 6 weeks. AI tumors expressed significantly higher levels of SREBP-1. In summary, the LNCaP xenograft model of human prostate cancer as well as clinical specimens of prostate cancer demonstrated an up-regulation of SREBPs and their downstream effector genes during progression to androgen independence. As the AI phenotype emerges, enzymes critical for lipogenesis and cholesterol synthesis are activated and likely contribute significantly to cell survival of AI prostate cancer.