Development of New Treatments for Prostate Cancer

The Dean and Betty Gallo Prostate Cancer Center (GPCC) was established with the goal of eradicating prostate cancer and improving the lives of men at risk for the disease through research, treatment, education and prevention. GPCC was founded in the memory of Dean Gallo, a beloved New Jersey Congressman who died tragically of prostate cancer diagnosed at an advanced stage. GPCC unites a team of outstanding researchers and clinicians who are committed to high-quality basic research, translation of innovative research to the clinic, exceptional patient care, and improving public education and awareness of prostate cancer. GPCC is a center of excellence of The Cancer Institute of New Jersey, which is the only NCI-designated comprehensive cancer center in the state. GPCC efforts are now integrated well as part of our Prostate Program at CINJ, in which Dr. Robert DiPaola and Dr. Cory Abate-Shen are co-leaders. The Prostate Program unites 19 investigators from 10 academic departments who have broad and complementary expertise in prostate cancer research. The overall goal and unifying theme is to elucidate basic mechanisms of prostate growth and oncogenesis, with the ultimate goal of promoting new and effective strategies for the eradication of prostate cancer. Members' wide range of research interests collectively optimize the chances of providing new insights into normal prostate biology and unraveling the molecular pathophysiology of prostate cancer. Cell culture and powerful animal models developed by program members recapitulate the various stages of prostate cancer progression, including prostatic intraepithelial neoplasia, adenocarcinoma, androgen-independence, invasion and metastases. These models promise to further strengthen an already robust program of investigator-initiated therapeutic clinical trials, including studies adopted by national cooperative groups. Efforts to translate laboratory results into clinical studies of early detection and chemoprevention are underway. The specific goals of this program are: (1) To investigate the molecular mechanisms underlying normal prostate growth and differentiation and elucidate the molecular mechanisms underlying prostate oncogenesis. (2) To build on fundamental knowledge to develop effective therapeutic approaches for the treatment of prostate cancer. (3) To improve the control of prostate cancer through early detection, chemoprevention, and outreach and education. This new disease-based program is structured to improve interdisciplinary interactions and translational results. Already, through the dynamic leadership of Drs. Cory Abate-Shen and Robert DiPaola, new investigators were attracted to the field, new collaborations engendered, and numerous investigator-initiated trials implemented. Progress in GPCC and the program overall has been outstanding. The Center has success in uniting investigators with broad and complementary expertise in prostate cancer research. The overall goal and unifying theme is to elucidate basic mechanisms of prostate growth and oncogenesis, with the ultimate goal of promoting new and effective strategies for the eradication of prostate cancer in patients and populations at risk. Members wide range of research interests collectively optimize the chances of providing new insights into normal prostate biology and unraveling the molecular pathophysiology of prostate cancer. Studies in cell culture and powerful animal models developed recapitulate the various stages of prostate cancer progression, including prostatic intraepithelial neoplasia, adenocarcinoma, androgen-independence, invasion and metastases. These models promise to further strengthen an already robust program of investigator-initiated therapeutic clinical trials, including studies adopted by national cooperative groups. Efforts to translate laboratory results into clinical studies of early detection and chemoprevention are underway

A network biology approach to prostate cancer

There is a need to identify genetic mediators of solid-tumor cancers, such as prostate cancer, where invasion and distant metastases determine the clinical outcome of the disease. Whole-genome expression profiling offers promise in this regard, but can be complicated by the challenge of identifying the genes affected by a condition from the hundreds to thousands of genes that exhibit changes in expression. Here, we show that reverse-engineered gene networks can be combined with expression profiles to compute the likelihood that genes and associated pathways are mediators of a disease. We apply our method to non-recurrent primary and metastatic prostate cancer data, and identify the androgen receptor gene (AR) among the top genetic mediators and the AR pathway as a highly enriched pathway for metastatic prostate cancer. These results were not obtained on the basis of expression change alone. We further demonstrate that the AR gene, in the context of the network, can be used as a marker to detect the aggressiveness of primary prostate cancers. This work shows that a network biology approach can be used advantageously to identify the genetic mediators and mediating pathways associated with a disease

BRCA1: linking HOX to breast cancer suppression

Homeobox (HOX) genes play key roles in embryogenesis and tissue differentiation. Recently, a number of groups have reported altered HOX gene expression in breast cancer. However, the mechanism of HOX gene regulation and the search for direct targets of its transcriptional regulatory function have been minimally fruitful. Recently, Gilbert and colleagues reported that HOXA9 restrains breast cancer progression by upregulation of BRCA1, a tumor suppressor. This finding raises our hope that more, rather elusive targets of HOX genes important in tumor progression or suppression will be found in the future

Delineation of prognostic biomarkers in prostate cancer

Prostate cancer is the most frequently diagnosed cancer in American men(1,2). Screening for prostate-specific antigen (PSA) has led to earlier detection of prostate cancer(3), but elevated serum PSA levels may be present in non-malignant conditions such as benign prostatic hyperlasia (BPH). Characterization of gene-expression profiles that molecularly distinguish prostatic neoplasms may identify genes involved in prostate carcinogenesis, elucidate clinical biomarkers, and lead to an improved classification of prostate cancer(4-6). Using microarrays of complementary DNA, we examined gene-expression profiles of more than 50 normal and neoplastic prostate specimens and three common prostate-cancer cell lines. Signature expression profiles of normal adjacent prostate (NAP), BPH, localized prostate cancer, and metastatic, hormone-refractory prostate cancer were determined. Here we establish many associations between genes and prostate cancer. We assessed two of these genes-hepsin, a transmembrane serine protease, and pim-1, a serine/threonine kinase-at the protein level using tissue microarrays consisting of over 700 clinically stratified prostate-cancer specimens. Expression of hepsin and pim-1 proteins was significantly correlated with measures of clinical outcome. Thus, the integration of cDNA microarray, high-density tissue microarray, and linked clinical and pathology data is a powerful approach to molecular profiling of human cancer.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62849/1/412822a0.pd

BRAF Activation Initiates but Does Not Maintain Invasive Prostate Adenocarcinoma

Prostate cancer is the second leading cause of cancer-related deaths in men. Activation of MAP kinase signaling pathway has been implicated in advanced and androgen-independent prostate cancers, although formal genetic proof has been lacking. In the course of modeling malignant melanoma in a tyrosinase promoter transgenic system, we developed a genetically-engineered mouse (GEM) model of invasive prostate cancers, whereby an activating mutation of BRAFV600E–a mutation found in ∼10% of human prostate tumors–was targeted to the epithelial compartment of the prostate gland on the background of Ink4a/Arf deficiency. These GEM mice developed prostate gland hyperplasia with progression to rapidly growing invasive adenocarcinoma without evidence of AKT activation, providing genetic proof that activation of MAP kinase signaling is sufficient to drive prostate tumorigenesis. Importantly, genetic extinction of BRAFV600E in established prostate tumors did not lead to tumor regression, indicating that while sufficient to initiate development of invasive prostate adenocarcinoma, BRAFV600E is not required for its maintenance

Multiple Oncogenic Pathway Signatures Show Coordinate Expression Patterns in Human Prostate Tumors

BACKGROUND: Gene transcription patterns associated with activation of oncogenes Myc, c-Src, beta-catenin, E2F3, H-Ras, HER2, EGFR, MEK, Raf, MAPK, Akt, and cyclin D1, as well as of the cell cycle and of androgen signaling have been generated in previous studies using experimental models. It was not clear whether genes in these "oncogenic signatures" would show coordinate expression patterns in human prostate tumors, particularly as most of the signatures were derived from cell types other than prostate. PRINCIPAL FINDINGS: The above oncogenic pathway signatures were examined in four different gene expression profile datasets of human prostate tumors (representing approximately 250 patients in all), using both Q1-Q2 and one-sided Fisher's exact enrichment analysis methods. A significant fraction (approximately 5%) of genes up-regulated experimentally by Myc, c-Src, HER2, Akt, or androgen were co-expressed in human tumors with the oncogene or biomarker corresponding to the pathway signature. Genes down-regulated experimentally, however, did not show anticipated patterns of anti-enrichment in the human tumors. CONCLUSIONS: Significant subsets of the genes in these experimentally-derived oncogenic signatures are relevant to the study of human prostate cancer. Both molecular biologists and clinical researchers could focus attention on the relatively small number of genes identified here as having coordinate patterns that arise from both the experimental system and the human disease system

The Pace of Prostatic Intraepithelial Neoplasia Development Is Determined by the Timing of Pten Tumor Suppressor Gene Excision

Loss of the PTEN tumor suppressor is a common occurrence in human prostate cancer, particularly in advanced disease. In keeping with its role as a pivotal upstream regulator of the phosphatidylinositol 3-kinase signaling pathway, experimentally-induced deletion of Pten in the murine prostate invariably results in neoplasia. However, and unlike humans where prostate tumorigenesis likely evolves over decades, disease progression in the constitutively Pten deficient mouse prostate is relatively rapid, culminating in invasive cancer within several weeks post-puberty. Given that the prostate undergoes rapid androgen-dependent growth at puberty, and that Pten excisions during this time might be especially tumorigenic, we hypothesized that delaying prostate-specific Pten deletions until immediately after puberty might alter the pace of tumorigenesis. To this end we generated mice with a tamoxifen-inducible Cre recombinase transgene enabling temporal control over prostate-specific gene alterations. This line was then interbred with mice carrying floxed Pten alleles. Despite evidence of increased Akt/mTOR/S6K axis activity at early time points in Pten-deficient epithelial cells, excisions induced in the post-pubertal (6 wk-old) prostate yielded gradual acquisition of a range of lesions. These progressed from pre-malignant changes (nuclear atypia, focal hyperplasia) and low grade prostatic intraepithelial neoplasia (PIN) at 16–20 wks post-tamoxifen exposure, to overtly malignant lesions by ∼1 yr of age, characterized by high-grade PIN and microinvasive carcinoma. In contrast, when Pten excisions were triggered in the pre-pubertal (2 week-old) prostate, neoplasia evolved over a more abbreviated time-frame, with a spectrum of premalignant lesions, as well as overt PIN and microinvasive carcinoma by 10–12 wks post-tamoxifen exposure. These results indicate that the developmental stage at which Pten deletions are induced dictates the pace of PIN development

miRNA-135a promotes breast cancer cell migration and invasion by targeting HOXA10

<p>Abstract</p> <p>Background</p> <p>miRNAs are a group of small RNA molecules regulating target genes by inducing mRNA degradation or translational repression. Aberrant expression of miRNAs correlates with various cancers. Although miR-135a has been implicated in several other cancers, its role in breast cancer is unknown. <it>HOXA10 </it>however, is associated with multiple cancer types and was recently shown to induce p53 expression in breast cancer cells and reduce their invasive ability. Because <it>HOXA10 </it>is a confirmed miR-135a target in more than one tissue, we examined miR-135a levels in relation to breast cancer phenotypes to determine if miR-135a plays role in this cancer type.</p> <p>Methods</p> <p>Expression levels of miR-135a in tissues and cells were determined by poly (A)-RT PCR. The effect of miR-135a on proliferation was evaluated by CCK8 assay, cell migration and invasion were evaluated by transwell migration and invasion assays, and target protein expression was determined by western blotting. GFP and luciferase reporter plasmids were constructed to confirm the action of miR-135a on downstream target genes including <it>HOXA10</it>. Results are reported as means ± S.D. and differences were tested for significance using 2-sided Student"s t-test.</p> <p>Results</p> <p>Here we report that miR-135a was highly expressed in metastatic breast tumors. We found that the expression of miR-135a was required for the migration and invasion of breast cancer cells, but not their proliferation. <it>HOXA10</it>, which encodes a transcription factor required for embryonic development and is a metastasis suppressor in breast cancer, was shown to be a direct target of miR-135a in breast cancer cells. Our analysis showed that miR-135a suppressed the expression of <it>HOXA10 </it>both at the mRNA and protein level, and its ability to promote cellular migration and invasion was partially reversed by overexpression of <it>HOXA10</it>.</p> <p>Conclusions</p> <p>In summary, our results indicate that miR-135a is an onco-miRNA that can promote breast cancer cell migration and invasion. <it>HOXA10 </it>is a target gene for miR-135a in breast cancer cells and overexpression of <it>HOXA10 </it>can partially reverse the miR-135a invasive phenotype.</p

Epidermal growth factor receptor structural alterations in gastric cancer

<p>Abstract</p> <p>Background</p> <p>EGFR overexpression has been described in many human tumours including gastric cancer. In NSCLC patients somatic EGFR mutations, within the kinase domain of the protein, as well as gene amplification were associated with a good clinical response to EGFR inhibitors. In gastric tumours data concerning structural alterations of EGFR remains controversial. Given its possible therapeutic relevance, we aimed to determine the frequency and type of structural alterations of the <it>EGFR </it>gene in a series of primary gastric carcinomas.</p> <p>Methods</p> <p>Direct sequencing of the kinase domain of the <it>EGFR </it>gene was performed in a series of 77 primary gastric carcinomas. FISH analysis was performed in 30 cases. Association studies between <it>EGFR </it>alterations and the clinical pathological features of the tumours were performed.</p> <p>Results</p> <p>Within the 77 primary gastric carcinomas we found two <it>EGFR </it>somatic mutations and several <it>EGFR </it>polymorphisms in exon 20. Six different intronic sequence variants of <it>EGFR </it>were also found. Four gastric carcinomas showed balanced polysomy or <it>EGFR </it>gene amplification. We verified that gastric carcinoma with alterations of <it>EGFR </it>(somatic mutations or copy number variation) showed a significant increase of tumour size (<it>p </it>= 0.0094) in comparison to wild-type <it>EGFR </it>carcinomas.</p> <p>Conclusion</p> <p>We demonstrate that <it>EGFR </it>structural alterations are rare in gastric carcinoma, but whenever present, it leads to tumour growth. We considered that searching for <it>EGFR </it>alterations in gastric cancer is likely to be clinically important in order to identify patients susceptible to respond to tyrosine kinase inhibitors.</p

Prostate tumor attenuation in the nu/nu murine model due to anti-sarcosine antibodies in folate-targeted liposomes

Herein, we describe the preparation of liposomes with folate-targeting properties for the encapsulation of anti-sarcosine antibodies (antisarAbs@LIP) and sarcosine (sar@LIP). The competitive inhibitory effects of exogenously added folic acid supported the role of folate targeting in liposome internalization. We examined the effects of repeated administration on mice PC-3 xenografts. Sar@LIP treatment significantly increased tumor volume and weight compared to controls treated with empty liposomes. Moreover, antisarAbs@LIP administration exhibited a mild antitumor effect. We also identified differences in gene expression patterns post-treatment. Furthermore, Sar@LIP treatment resulted in decreased amounts of tumor zinc ions and total metallothioneins. Examination of the spatial distribution across the tumor sections revealed a sarcosine-related decline of the MT1X isoform within the marginal regions but an elevation after antisarAbs@LIP administration. Our exploratory results demonstrate the importance of sarcosine as an oncometabolite in PCa. Moreover, we have shown that sarcosine can be a potential target for anticancer strategies in management of PCa