Expression study of three secretory proteins (prostatic secretory protein of 94 amino acids, probasin, and seminal vesicle secretion II) in dysplastic and neoplastic rat prostates

Histomathematical Analysis of Clinical Specimens: Challenges and Progress

Proteomic analysis of clinical tissue specimens is a difficult undertaking. Described here is a multiplex study of protein expression levels in histological sections of human prostate that addresses many of the associated challenges. Whole-mount sections from 10 prostatectomy specimens were studied using 15 antibodies, immunohistochemical staining, digital imaging, and mathematical analysis of the data sets. The approach was successful in stratifying cell lineages present in the samples based on proteomic patterns, including differentiating normal epithelium from cancer. This strategy likely will be a useful method for extending the number of proteins that can be analyzed in clinical cancer specimens using currently available laboratory techniques.

Purification and preliminary X-ray crystallographic studies of beta-microseminoprotein from human seminal plasma

beta-Microseminoprotein (beta-MSP) is a small cysteine-rich protein with a molecular mass of 10 kDa. It was first isolated from human seminal plasma and has subsequently been identified from several species. Comparison of the amino-acid sequences of beta-MSP proteins suggests that the protein is a rapidly evolving protein. The function of beta-MSP is poorly understood. Furthermore, no crystal structure has been reported of any beta-MSP; therefore, determination of the crystal structure of beta-MSP is the foremost task in order to understand the function of this protein completely. Here, the purification, crystallization and preliminary X-ray diffraction analysis of beta-MSP from human seminal plasma are described. The protein was purified using anion-exchange and size-exclusion chromatography and the purified protein was crystallized using 0.1 M ammonium sulfate, 0.1 M HEPES buffer pH 7.0 and 20%(w/v) PEG 3350. The crystals belonged to the tetragonal space group P4(3)22 and contained three beta-MSP molecules in the asymmetric unit. X-ray intensity data were collected to 2.4 A resolution.

Histopathological evidence for an association of inflammation with ductal pin-like lesions but not with ductal adenocarcinoma in the prostate of the noble rat

BACKGROUND

Chronic inflammation may contribute to the development of prostate cancer. The goal of this study was to determine the possible association of prostatic inflammation, prostatic intraepithelial neoplasia (PIN)-like lesion, and prostate cancer, and to assess the androgen and estrogen dependency of the early steps of carcinogenesis.

METHODS

Noble rats were treated with testosterone and estradiol implants for 13, 18, or 26 weeks. Hormone dependency of the lesions was studied in a subset of animals by removing hormone implants for 3 weeks after 15 weeks treatment time.

RESULTS

After treatment for 13 weeks, acute and chronic inflammation was found in the dorsolateral prostate lobes and both inflammation and PIN-like lesions were present in the periurethal area of the prostate in all animals (n = 8). Following hormone exposure for 18 and 26 weeks, inflammation in the prostate remained, and adenocarcinomas in the periurethal prostate area with no adjacent inflammation were observed in all 18 animals studied. When both hormone implants were removed after 15 weeks, PIN-like lesions progressed further to adenocarcinoma only in two of seven animals. When only the estradiol implants were removed, three of five animals developed adenocarcinomas.

CONCLUSIONS

Even though adenocarcinomas were not morphologically associated with inflammation, PIN-like lesions preceding adenocarcinoma were found in close association with inflammation, pointing towards a possible initiator role of inflammation in the early steps of prostatic carcinogenesis. Further, these results indicate that both androgens and estrogens together play a significant role in the induction of inflammation and prostatic cancer in this model.

Molecular cloning and functional study of rat estrogen receptor-related receptor gamma in rat prostatic cells

BACKGROUND

Based on high homology of ERRs with ERs, we hypothesize that ERRs might functionally cross talk with ERs or independently in prostatic cells.

METHODS

We examined the ERRgamma expressions in rat prostates and Nb rat prostate cancer model, and its growth regulation in stable transfectants of prostatic cells.

RESULTS

We cloned the ERRgamma cDNA from rat prostate by RACE-PCR. Its expression was confirmed by Northern and immunoblottings. Real-time RT-PCR showed that its expression in castrated prostates was androgen-dependent. ERRgamma was expressed in prostatic epithelial cells, but showed reduced expressions in neoplastic prostates. Transfections confirmed that ERRgamma was expressed in prostatic cells as nuclear protein and transcriptionally active without estradiol. Its overexpression in ERRgamma-stable transfectants of NbE-1 and MAT-Lu cells inhibited their in vitro proliferation, anchorage-independent growth in soft-agar and tumorigenicity in nude mice.

CONCLUSIONS

Our studies show that ERRgamma is functionally expressed in rat prostate and may play anti-proliferative actions in prostatic cells. Its co-expression with ERs suggests that besides ERs, ligand-independent ERRgamma is also involved in prostatic growth and functions.

A Novel Serum Marker, Total Prostate Secretory Protein of 94 Amino Acids, Improves Prostate Cancer Detection and Helps Identify High Grade Cancers at Diagnosis

PURPOSE

New biomarkers for prostate cancer are needed. We determined whether a novel serum marker, total PSP94 can be used to accomplish these goals.

MATERIALS AND METHODS

We conducted a case-control study of 1,212 men with no previous history of prostate cancer and who underwent a prostate biopsy from 1998 to 2000 because of an increased PSA or an abnormal DRE. Serum PSP94 levels were assessed using a sandwich enzyme-linked immunosorbent assay technique. Cases were patients with prostate cancer, and controls were patients who had no evidence of cancer. Multivariate logistic regression analysis was used to determine whether or not PSP94 levels improved the predictive value for prostate cancer.

RESULTS

Of the 1,212 men 596 (49.2%) had cancer detected. The median PSP94 level was significantly lower among cases (2.60 ng/ml) than among controls (3.40 ng/ml, p <0.0001). The adjusted odds ratios for the presence of prostate cancer for patients with the lowest quartile of PSP94, compared to patients in the highest quartile was 2.70 (95% CI 1.8 - 4.0, p <0.0001). Among a subgroup of 649 men in whom PSA had a low predictive value (PSA less than 20 ng/ml, normal DRE and less than 70 years), 260 (40.1%) were found to have cancer. In this subgroup total PSP94 levels helped discriminate between patients with high grade disease (Gleason score 8 or more, median 1.90 ng/ml), moderate grade disease (Gleason score 7, median 2.34 ng/ml) and low grade disease (Gleason score 6 or less, median 2.60 ng/ml, p = 0.007). PSA and the FTPSA were not able to distinguish between patients with different grades in this group.

CONCLUSIONS

Patients with low total PSP94 levels had a high probability for having prostate cancer detected at biopsy. The total PSP94 level was able to help identify patients with high grade disease among a subset of patients in whom PSA and FTPSA are least informative.

Expression signature of the mouse prostate

Genetically engineered mice are being used increasingly for delineating the molecular mechanisms of prostate cancer development. Epithelium-stroma interactions play a critical role in prostate development and tumorigenesis. To better understand gene expression patterns in the normal sexually mature mouse prostate, epithelium and stroma were laser-capture microdissected from ventral, dorsolateral, and anterior prostate lobes. Genome-wide expression was measured by DNA microarrays. Our analysis indicated that the gene expression pattern in the mouse dorsolateral lobe was closest to that of the human prostate peripheral zone, supporting the hypothesis that these prostate compartments are functionally equivalent. Stroma from a given lobe had closer gene expression patterns with stroma from other lobes than epithelium from the same lobe. Stroma appeared to have higher expression complexity than epithelium. Specifically, stromal cells had higher expression levels of genes implicated in cell adhesion, muscle development, and contraction, in structural constituents of cytoskeleton and actin binding, and in components such as sarcomere and extracellular matrix collagen. Among the genes that were enriched in the epithelium were secretory proteins, including seminal vesicle protein secretion 2 and 5. Surprisingly, prostate stroma expressed many osteogenic molecules, as confirmed by immunohistochemistry. A "bone-like" environment in the prostate may predispose prostate cells for survival in the bone. Chemokine Cxcl12 but not its receptor, Cxcr4, was expressed in normal prostate. In prostate tumors, interestingly, Cxcl12 was up-regulated in epithelial cells with a concomitant expression of Cxcr4. Expression of both the receptor and ligand may provide an autocrine mechanism for tumor cell migration and invasion.

Annotation of androgen dependence to human prostate cancer-associated genes by microarray analysis of mouse prostate

In silico methods and array technologies have identified genes differentially expressed in prostate cancer. Biological functions of the identified genes are often unclear. Considering the biological significance of androgens in prostate cancer, we profiled the prostate transcripts of congenital androgen-deficient mice with or without androgen replacement in vivo using murine gene expression array. In parallel genes differentially expressed in human prostate cancer were identified by Digital Differential Display and the Serial Analysis of Gene Expression. Androgen dependence of the identified genes was then determined by the steady-state mRNA levels of the murine orthologs in response to androgen treatment. The annotation is supported by the finding that some of the androgen target genes have been reported previously with independent experiments.

Expression of Foxa transcription factors in the developing and adult murine prostate

BACKGROUND

The Foxa family (a1, a2, and a3) of proteins are transcription factors that are central to endodermal development. Recently, Foxa1 has been shown to regulate the transcription of several murine and human prostate specific genes involved in differentiated function by interacting with DNA promoter sequences and androgen receptors. Currently, the developmental expression pattern of Foxa proteins in the murine prostate is unknown.

METHODS

Male CD-1 mice (embryonic, prepubertal, pubertal, and adult) were used for immunohistochemical analysis of Foxa1, a2, and a3. Immunofluorescence was also performed for androgen receptor and cytokeratin 14 expression. Prostate tissue from pre-pubertal, pubertal, and adult mice were analyzed by Western blot and RT-PCR analysis for Foxa1, a2, and a3 expression.

RESULTS

Strong Foxa1 immunoreactivity was observed in epithelial cells throughout prostate development, growth, and adult differentiation. Prominent Foxa2 protein expression was only observed in the early stages of prostate development and was exclusively localized to epithelial cells of the forming buds. RT-PCR analysis identified low Foxa2 mRNA expression levels in the ventral and dorsolateral lobes of the adult prostate, with Foxa2 epithelial cell expression being localized to periurethral regions of the murine adult prostatic complex. Foxa3 expression was not observed in the murine prostate.

CONCLUSIONS

Foxa proteins represent epithelial cell markers in the murine prostate gland. The early expression of Foxa1 and a2 proteins in prostate formation suggests that these proteins play an important role in normal prostate development, in addition to differentiated secretory function.