Profiling of differential expression of messenger RNA in normal, benign, and metastatic prostate cell lines

Identification of an antibody fragment specific for androgen-dependent prostate cancer cells

Background

Prostate cancer is the most-diagnosed non-skin cancer among males in the US, and the second leading cause of cancer-related death. Current methods of treatment and diagnosis are not specific for the disease. This work identified an antibody fragment that binds selectively to a molecule on the surface of androgen-dependent prostate cancer cells but not benign prostatic cells.

Results

Antibody fragment identification was achieved using a library screening and enrichment strategy. A library of 10⁹ yeast-displayed human non-immune antibody fragments was enriched for those that bind to androgen-dependent prostate cancer cells, but not to benign prostatic cells or purified prostate-specific membrane antigen (PSMA). Seven rounds of panning and fluorescence-activated cell sorting (FACS) screening yielded one antibody fragment identified from the enriched library. This molecule, termed HiR7.8, has a low-nanomolar equilibrium dissociation constant (K_d) and high specificity for androgen-dependent prostate cancer cells.

Conclusions

Antibody fragment screening from a yeast-displayed library has yielded one molecule with high affinity and specificity. With further pre-clinical development, it is hoped that the antibody fragment identified using this screening strategy will be useful in the specific detection of prostate cancer and in targeted delivery of therapeutic agents for increased efficacy and reduced side effects.

Preclinical evaluation of the supercritical extract of azadirachta indica (neem) leaves in vitro and in vivo on inhibition of prostate cancer tumor growth

Azadirachta indica, commonly known as neem, has gained worldwide prominence because of its medical properties, namely antitumor, antiviral, anti-inflammatory, antihyperglycemic, antifungal, and antibacterial activities. Despite these promising results, gaps remain in our understanding of the molecular mechanism of action of neem compounds and their potential for use in clinical trials. We investigated supercritical extract of neem leaves (SENL) for the following: molecular targets in vitro, in vivo efficacy to inhibit tumor growth, and bioactive compounds that exert antitumor activity. Treatment of LNCaP-luc2 prostate cancer cells with SENL suppressed dihydrotestosterone-induced androgen receptor and prostate-specific antigen levels. SENL inhibited integrin β1, calreticulin, and focal adhesion kinase activation in LNCaP-luc2 and PC3 prostate cancer cells. Oral administration of SENL significantly reduced LNCaP-luc2 xenograft tumor growth in mice with the formation of hyalinized fibrous tumor tissue, reduction in the prostate-specific antigen, and increase in AKR1C2 levels. To identify the active anticancer compounds, we fractionated SENL by high-pressure liquid chromatography and evaluated 16 peaks for cytotoxic activity. Four of the 16 peaks exhibited significant cytotoxic activity against prostate cancer cells. Mass spectrometry of the isolated peaks suggested the compounds with cytotoxic activity were nimbandiol, nimbolide, 2',3'-dihydronimbolide, and 28-deoxonimbolide. Analysis of tumor tissue and plasma samples from mice treated with SENL indicated 28-deoxonimbolide and nimbolide as the bioactive compounds. Overall, our data revealed the bioactive compounds in SENL and suggested that the anticancer activity could be mediated through alteration in androgen receptor and calreticulin levels in prostate cancer.

Prostate cancer invasion and metastasis: insights from mining genomic data

Prostate cancer (PCa) is the second most commonly diagnosed malignancy in men in the Western world and the second leading cause of cancer-related deaths among men worldwide. Although most cancers have the potential to metastasize under appropriate conditions, PCa favors the skeleton as a primary site of metastasis, suggesting that the bone microenvironment is conducive to its growth. PCa metastasis proceeds through a complex series of molecular events that include angiogenesis at the site of the original tumor, local migration within the primary site, intravasation into the blood stream, survival within the circulation, extravasation of the tumor cells to the target organ and colonization of those cells within the new site. In turn, each one of these steps involves a complicated chain of events that utilize multiple protein-protein interactions, protein signaling cascades and transcriptional changes. Despite the urgent need to improve current biomarkers for diagnosis, prognosis and drug resistance, advances have been slow. Global gene expression methods such as gene microarrays and RNA sequencing enable the study of thousands of genes simultaneously and allow scientists to examine molecular pathways of cancer pathogenesis. In this review, we summarize the current literature that explored high-throughput transcriptome analysis toward the advancement of biomarker discovery for PCa. Novel biomarkers are strongly needed to enable more accurate detection of PCa, improve prediction of tumor aggressiveness and facilitate the discovery of new therapeutic targets for tailored medicine. Promising molecular markers identified from gene expression profiling studies include HPN, CLU1, WT1, WNT5A, AURKA and SPARC.

Lycopene modulates growth and survival associated genes in prostate cancer

Lycopene is a fat soluble red-orange carotenoid pigment present in tomato that reduces the risk for prostate cancer, a common malignancy among men. However, the mechanism by which lycopene attenuates prostate cancer is not fully defined. In this study we examined the effect of lycopene on proliferation, survival, and biomarker gene expression in prostate cancer (PC-3) cells in culture. WST-1 assay showed that lycopene induces a biphasic effect on PC-3 cells with a modest increase in proliferation at 1-5 μM, no change at 10-25 μM and a decrease at 50-100 μM doses in culture. Interestingly, combination treatment with lycopene induced anti-proliferative effect of Temozolomide on PC-3 cells. Lycopene also augmented the anti-proliferative effect of peroxisome proliferator-activated receptor gamma (PPARγ) agonists, but not Doxorubicin or Taxol, in prostate cancer. Flow cytometry analyses showed that lycopene, in combination with chemotherapeutic agents and PPARγ agonists, induced modest cell cycle arrest with significant increase in cell death by apoptosis and necrosis on prostate cancer. Gene array and quantitative reverse transcription polymerase chain reaction analyses showed that lycopene alters the expression of growth and apoptosis associated biomarkers in PC-3 cells. These findings highlight that lycopene attenuates prostate cancer by modulating the expression of growth and survival associated genes.

Correlation of serum β2-microglobulin levels with prostate-specific antigen, Gleason score, clinical stage, tumor metastasis and therapy efficacy in prostate cancer

BACKGROUND AND AIMS

Despite previous reports implying a role of β2-microglobulin (β2M) in the development of prostate cancer (PCa), the correlation of serum β2M with the clinicopathological features, therapy efficacy and prognosis of patients with PCa have not been fully clarified. The present study aims to investigate the serum levels of β2M in patients with PCa and explore the potential use of β2M as a tumor marker for diagnosis, treatment and prognosis of PCa.

METHODS

Serum β2M levels in 120 patients with PCa, 50 patients with benign prostate hyperplasia (BPH) and 85 healthy age-matched controls were measured by enzyme immunoassay. The correlation of serum β2M with the clinicopathological features, therapy efficacy and the prognosis of PCa were subsequently assessed.

RESULTS

Our results showed that: (i) PCa patients had significantly higher levels of β2M compared to those of patients with BPH or those of healthy controls. (ii) Serum β2M were markedly elevated in patients with high stage or grade PCa as compared to patients with low stage or grade PCa. (iii) We measured significantly higher levels of β2M in patients with metastasis as compared to patients lacking metastasis. (iv) During follow-up, serum β2M showed a marked decrease after successful therapy and a significant further increase in recurrent disease.

CONCLUSIONS

Our results demonstrate that serum β2M is correlated closely with the clinical stage, Gleason grade, PSA, distant metastasis and therapy efficacy in patients with PCa. Serum β2M may be a useful biomarker for clinical diagnosis, follow-up and prognosis of PCa.

Enterolactone restricts the proliferation of the LNCaP human prostate cancer cell line in vitro

Ecological data suggest a long-term diet high in plant material rich in biologically active compounds, such as the lignans, can significantly influence the development of prostate cancer over the lifetime of an individual. The capacity of a pure mammalian lignan, enterolactone (ENL), to influence the proliferation of the LNCaP human prostate cancer cell line was investigated as a function of cell density, metabolic activity, expression and secretion of prostate specific antigen (PSA), cell cycle profile, and the expression of genes involved in development and progression of prostate cancer. Treatment with a subcytotoxic concentration of ENL (60 muM for 72 h) was found to reduce: cell density (57.5%, SD 7.23, p < 0.001), metabolic activity (55%, SD 0.03, p < 0.001), secretion of PSA (48.50% SD 4.74, p = 0.05) and induce apoptosis (8.33-fold SD 0.04, p = 0.001) compared to untreated cells. Cotreatment with 10 muM etoposide was found to increase apoptosis by 50.17% (SD 0.02, p < 0.001). Additionally, several key genes (e. g. MCMs, survivin and CDKs) were beneficially regulated by ENL treatment (p < 0.05). The data suggest that the antiproliferative activity of ENL is a consequence of altered expression of cell cycle associated genes and provides novel molecular evidence for the antiproliferative properties of a pure lignan in prostate cancer.

Identification of prostate cancer mRNA markers by averaged differential expression and their detection in biopsies, blood, and urine

The advent of serum prostate-specific antigen (PSA) as a biomarker has enabled early detection of prostate cancer and, hence, improved clinical outcome. However, a low PSA is not a guarantee of disease-free status, and an elevated PSA is frequently associated with a negative biopsy. Therefore, our goal is to identify molecular markers that can detect prostate cancer with greater specificity in body fluids such as urine or blood. We used the RT-PCR differential display method to first identify mRNA transcripts differentially expressed in tumor vs. patient-matched nontumor prostate tissue. This analysis led to the identification of 44 mRNA transcripts that were expressed differentially in some but not all tumor specimens examined. To identify mRNA transcripts that are differentially expressed in most tumor specimens, we turned to differential display of pooled tissue samples, a technique we name averaged differential expression (ADE). We performed differential display of mRNA from patient-matched nontumor vs. tumor tissue, each pooled from 10 patients with various Gleason scores. Differentially expressed mRNA transcripts identified by ADE were fewer in number, but were expressed in a greater percentage of tumors (>75%) than those identified by differential display of mRNA from individual patient samples. Differential expression of these mRNA transcripts was also detected by RT-PCR in mRNA isolated from urine and blood samples of prostate cancer patients. Our findings demonstrate the principle that specific cDNA probes of frequently differentially expressed mRNA transcripts identified by ADE can be used for the detection of prostate cancer in urine and blood samples.

Differentially expressed genes in the prostate cancer cell line LNCaP after exposure to androgen and anti-androgen

Androgens play an important role in growth and maintenance of prostate cells. The actions of androgens are mediated by the androgen receptor (AR), a transcription factor member of the super-family of nuclear hormone receptors. Androgen regulated genes (ARGs) are potential markers for early diagnosis and treatment of prostate cancer patients. In the present study, we used DDRT-PCR (differential display reverse transcriptase polymerase chain reaction) technique in order to investigate differentially expressed genes in the prostate cancer cell line LNCaP after treatment with dihydrotestosterone and bicalutamide for 6, 24, and 48 hours. Fifty-five differentially expressed fragments were isolated, cloned, and sequenced. Sequencing analysis of these fragments revealed 56 different transcripts that showed homology to transcription factors, cell cycle regulators, metabolic enzymes, and hypothetical proteins. Among the differentially expressed genes, SPA17 and DDEF2 were further validated using quantitative real time RT-PCR (qPCR) in a series of 25 prostate tumor samples. The DDEF2 gene is involved in adhesion and cell migration of monocytes, and the SPA17 gene might be involved in cellular signal transduction. The transcripts of both, SPA17 and DDEF2 genes, showed altered pattern of expression in the group of prostate tumors analyzed by qPCR. The differentially expressed genes identified in this study might provide new insights into the androgen signaling pathways in prostate cells.

Association of lipoprotein lipase gene polymorphism with risk of prostate cancer in a Japanese population

A high fat intake has been associated with prostate cancer risk, and gene polymorphisms of lipoprotein lipase (LPL) play an important role in plasma lipoprotein metabolism. We herein analyzed the association of LPL gene polymorphisms with the risk of prostate cancer in a Japanese population. Three single nucleotide polymorphisms (SNPs) of LPL designated as Ser447stop, HindIII and PvuII were genotyped by the polymerase chain reaction-restriction fragment length polymorphism method in 273 prostate cancer patients, 205 benign prostatic hyperplasia (BPH) patients and 230 male controls. The men with the CG + GG genotypes of the Ser447stop polymorphism had an increased risk of prostate cancer compared to those with the CC genotype [age-adjusted odds ratio (aOR) = 1.625; 95% CI = 1.068-2.471; p = 0.023]. Furthermore, the increased risk associated with the CG + GG genotypes was more strongly observed in patients with high-grade cancers (aOR = 2.843; 95% CI = 1.252-6.458; p = 0.039) or metastatic diseases (aOR = 2.300; 95% CI = 1.042-5.074; p = 0.013), whereas the risk was not significant in those with low- to intermediate-grade cancers or nonmetastatic diseases. In the HindIII and PvuII polymorphisms, there was no significant difference between the prostate cancer patients and the controls, and no significant results as for tumor grade and stage. None of the 3 polymorphisms showed any association with the risk of BPH. Our results suggest that the LPL Ser447stop polymorphism is a common genetic modifier for the development of prostate cancer, particularly that of high-grade and/or high-stage, in a Japanese population.

Future opportunities for the diagnosis and treatment of prostate cancer

Despite recent advances, current diagnostic tests and treatment of prostate cancer have limitations. In the last few years, numerous biomolecules have been investigated with the aim of improving diagnosis, including kallikrein-like proteases, growth factors and neuroendocrine markers. Analysis of susceptibility genes has also been a focus of attention. Extensive research into new therapeutic approaches is also underway, including targeting angiogenesis, immune regulation and stromal-epithelial interactions. Gene therapy, gene chip technology and proteomics have emerged as promising innovations. The host of novel diagnostic markers and therapies require appropriate validation, both phenotypical and functional. A further consideration is the need to re-evaluate clinical trial design and end points to facilitate progression of promising targets through the clinical trial process. Overall, the outlook for the treatment of prostate cancer looks promising, with any advances likely to require both a multimodal and multidisciplinary approach.

Cancer of unknown primary: changing approaches. A multidisciplinary case presentation from the Joan Karnell cancer center of pennsylvania hospital

Cancer of unknown primary is a common clinical syndrome, accounting for 2%-5% of cancer patients. A representative case is presented. This heterogenous group of disorders includes entities such as poorly differentiated carcinoma of unknown primary, adenocarcinoma of unknown primary, neuroendocrine carcinoma of unknown primary, squamous cell carcinoma of unknown primary, poorly differentiated (not otherwise specified) cancer of unknown primary, and melanoma of unknown primary. It is crucial to identify those treatment-responsive presentations of unknown primary with the greatest potential for long-term survival. This discussion emphasizes newer approaches to the diagnosis and treatment of unknown primary cancer, including advances in pathology with immunoperoxidase and molecular genetic techniques, positron emission tomography, and published chemotherapeutic trials. With the increased sophistication of pathologic and radiologic techniques, the frequency of unknown primary cancers will likely continue to decline. Further, as newer and more targeted therapies for specific types of cancer are identified, the previously held nihilism regarding the search for and identification of the primary may become less supportable.

LIM kinase 1 is essential for the invasive growth of prostate epithelial cells: implications in prostate cancer

Mammalian LIM kinase 1 (LIMK1) is involved in reorganization of actin cytoskeleton through inactivating phosphorylation of the ADF family protein cofilin, which depolymerizes actin filaments. Maintenance of the actin dynamics in an ordered fashion is essential for stabilization of cell shape or promotion of cell motility depending on the cell type. These are the two key phenomena that may become altered during acquisition of the metastatic phenotype by cancer cells. Here we show that LIMK1 is overexpressed in prostate tumors and in prostate cancer cell lines, that the concentration of phosphorylated cofilin is higher in metastatic prostate cancer cells, and that a partial reduction of LIMK1 altered cell proliferation by arresting cells at G2/M, changed cell shape, and abolished the invasiveness of metastatic prostate cancer cells. We also show that the ectopic expression of LIMK1 promotes acquisition of invasive phenotype by the benign prostate epithelial cells. Our data provide evidence of a novel role of LIMK1 in regulating cell division and invasive property of prostate cancer cells and indicate that the effect is not mediated by phosphorylation of cofilin. Our study correlates with the recent observations showing a metastasis-associated chromosomal gain on 7q11.2 in prostate cancer, suggesting a possible gain in LIMK1 DNA (7q11.23).