Faculty Bibliography

BACKGROUND: Recent advances in genomics, proteomics, and the increasing demands for biomarker validation studies have catalyzed changes in the landscape of cancer research, fueling the development of tissue banks for translational research. A result of this transformation is the need for sufficient quantities of clinically annotated and well-characterized biospecimens to support the growing needs of the cancer research community. Clinical annotation allows samples to be better matched to the research question at hand and ensures that experimental results are better understood and can be verified. To facilitate and standardize such annotation in bio-repositories, we have combined three accepted and complementary sets of data standards: the College of American Pathologists (CAP) Cancer Checklists, the protocols recommended by the Association of Directors of Anatomic and Surgical Pathology (ADASP) for pathology data, and the North American Association of Central Cancer Registry (NAACCR) elements for epidemiology, therapy and follow-up data. Combining these approaches creates a set of International Standards Organization (ISO) - compliant Common Data Elements (CDEs) for the mesothelioma tissue banking initiative supported by the National Institute for Occupational Safety and Health (NIOSH) of the Center for Disease Control and Prevention (CDC). METHODS: The purpose of the project is to develop a core set of data elements for annotating mesothelioma specimens, following standards established by the CAP checklist, ADASP cancer protocols, and the NAACCR elements. We have associated these elements with modeling architecture to enhance both syntactic and semantic interoperability. The system has a Java-based multi-tiered architecture based on Unified Modeling Language (UML). RESULTS: Common Data Elements were developed using controlled vocabulary, ontology and semantic modeling methodology. The CDEs for each case are of different types: demographic, epidemiologic data, clinical history, pathology data including block level annotation, and follow-up data including treatment, recurrence and vital status. The end result of such an effort would eventually provide an increased sample set to the researchers, and makes the system interoperable between institutions. CONCLUSION: The CAP, ADASP and the NAACCR elements represent widely established data elements that are utilized in many cancer centers. Herein, we have shown these representations can be combined and formalized to create a core set of annotations for banked mesothelioma specimens. Because these data elements are collected as part of the normal workflow of a medical center, data sets developed on the basis of these elements can be easily implemented and maintained

Androgen receptor (AR) mediates transcriptional activation of diverse target genes through interactions with various coactivators that may alter its function and help mediate the switch between prostate cell proliferation and differentiation. We recently identified p44/MEP50 as an AR coactivator and further showed that it is expressed primarily in the nucleus and cytoplasm of benign prostate epithelial and prostate cancer cells, respectively. We also showed that haploinsufficiency in p44(+/-) mice causes prostate epithelial cell proliferation. To establish direct cause-and-effect relationships, we have used p44 fusion proteins that are selectively expressed in the nucleus or cytoplasm of prostate cancer cells (LNCaP), along with RNAi analyses, to examine effects of p44 both in vitro and in vivo (in tumor xenografts). We show that preferential expression of p44 in the nucleus inhibits proliferation of LNCaP cells in an AR-dependent manner, whereas preferential expression of p44 in the cytoplasm enhances cell proliferation. These effects appear to be mediated, at least in part, through the regulation of distinct cell-cycle regulatory genes that include p21 (up-regulated by nuclear p44) and cyclin D2 and CDK6 (up-regulated by cytoplasmic p44). Importantly, we also demonstrate that altered p44 expression is associated with androgen-independent prostate cancer. Our results indicate that nuclear p44 and cytoplasmic p44 have distinct and opposing functions in the regulation of prostate cancer cell proliferation

High-mobility group A2 (HMGA2) is commonly overexpressed in large leiomyomas. HMGA2 is an important regulator of cell growth, differentiation, apoptosis, and transformation. As a predicted target of Let-7 microRNAs (Let-7s), HMGA2 can be repressed by Let-7s in vitro. MicroRNA profiling analysis revealed that Let-7s were significantly dysregulated in uterine leiomyomas: high in small leiomyomas and lower in large leiomyomas. To evaluate whether Let-7 repression of HMGA2 plays a major role in leiomyomas, we analyzed the molecular relationship of HMGA2 and Let-7s, both in vitro and in vivo. We first characterized that exogenous Let-7 microRNAs could directly repress the dominant transcript of HMGA2, HMGA2a. This repression was also identified for two cryptic HMGA2 transcripts in primary leiomyoma cultures. Second, we found that the endogenous Let-7s were biologically active and played a major role in the regulation of HMGA2. Then, we illustrated that Let-7 repression of HMGA2 inhibited cellular proliferation. Finally, we examined the expression levels of Let-7c and HMGA2 in a large cohort of leiomyomas (n = 120), and we found high levels of Let-7 and low levels of HMGA2 in small leiomyomas, and low levels of Let-7 and high levels of HMGA2 in large leiomyomas. Our findings suggest that the Let-7-mediated repression of HMGA2 mechanism can be an important molecular event in leiomyoma growth. (Mol Cancer Res 2008;6(4):663-73)

ABSTRACT: BACKGROUND: Midkine is a heparin-binding growth factor that is over-expressed in various human cancers and plays important roles in cell transformation, growth, survival, migration, and angiogenesis. However, little is known about the upstream factors and signaling mechanisms that regulate midkine gene expression. METHODS: Two prostate cancer cell lines LNCaP and PC3 were studied for their expression of midkine. Induction of midkine expression in LNCaP cells by serum, growth factors and cytokines was determined by Western blot analysis and/or real-time quantitative reverse-transcription - polymerase chain reaction (RT-PCR). The cell viability was determined by the trypan blue exclusion assay when the LNCaP cells were treated with tumor necrosis factor alpha (TNFalpha) and/or recombinant midkine. When the LNCaP cells were treated with recombinant midkine, activation of intracellular signalling pathways was determined by Western blot analysis. Prostate tissue microarray slides containing 129 cases (18 normal prostate tissues, 40 early stage cancers, and 71 late stage cancers) were assessed for midkine expression by immunohistochemical staining. RESULTS: We identified that fetal bovine serum, some growth factors (epidermal growth factor, androgen, insulin-like growth factor-I, and hepatocyte growth factor) and cytokines (TNFalpha and interleukin-1beta) induced midkine expression in a human prostate cancer cell line LNCaP cells. TNFalpha also induced midkine expression in PC3 cells. TNFalpha was the strongest inducer of midkine expression via nuclear factor-kappa B pathway. Midkine partially inhibited TNFalpha-induced apoptosis in LNCaP cells. Knockdown of endogenous midkine expression by small interfering RNA enhanced TNFalpha-induced apoptosis in LNCaP cells. Midkine activated extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase pathways in LNCaP cells. Furthermore, midkine expression was significantly increased in late stage prostate cancer, which coincides with previously reported high serum levels of TNFalpha in advanced prostate cancer. CONCLUSION: These findings provide the first demonstration that midkine expression is induced by certain growth factors and cytokines, particularly TNFalpha, which offers new insight into understanding how midkine expression is increased in the late stage prostate cancer

ARA70 was first identified as a gene fused to the ret oncogene in thyroid carcinoma and subsequently as a co-activator for androgen receptor (AR). Two isoforms of ARA70 have been identified: a 70-kDa version called ARA70 alpha and an internally spliced 35-kDa variant termed ARA70 beta. We have previously reported that ARA70 alpha expression is reduced in prostate cancer, and its overexpression inhibits proliferation of LNCaP prostate cancer cells. However, the function of the ARA70 beta isoform in prostate cancer is not understood. In this report we examined the effects of ARA70 beta on AR transcriptional regulation as well as prostate cancer cellular proliferation and invasion. Although both ARA70 alpha and ARA70 beta functioned as transcriptional co-activators of AR in cell-based reporter assays, ARA70 beta overexpression, in contrast to ARA70 alpha, promoted prostate cancer cellular proliferation and invasion through Matrigel. Interestingly, genome-wide expression profiling of cells expressing ARA70 beta revealed an increase in the expression of genes involved in the control of cell division and adhesion, compatible with a role for ARA70 beta in proliferation and invasion. Consistent with its function in promoting cell growth and invasion, ARA70 beta expression was increased in prostate cancer. Our findings implicate ARA70 beta as a regulator of tumor cell growth and metastasis by affecting gene expression

Lymphovascular invasion (LVI) of breast cancer is an independent adverse prognosticator that is associated with increased regional and distant tumor recurrence. LVI is infrequently encountered in invasive lobular carcinoma when compared to invasive ductal carcinoma. We employed D2-40 antibody, a novel marker for lymphatic endothelial cells, in an attempt to enhance the detection of LVI in invasive lobular carcinomas. We identified 78 patients with invasive lobular carcinoma with known axillary status, who were studied between 2003 and 2006. D2-40 antibody was applied to one representative paraffin block from each case and the results were compared to LVI on routine histology. LVI was identified in 12 (15%) and 19 (24%) cases by routine histology and D2-40 antibody, respectively. Eleven of 12 patients (92%) with LVI identified by routine histology had axillary nodal metastasis compared to 14 of 19 patients (74%) with LVI identified by D2-40 antibody. LVI was missed by routine histology in 8 cases (10%). D2-40 antibody enhanced the identification of LVI by 9% in node negative patients. D2-40 antibody increased the identification of LVI by 12% in classic invasive lobular carcinoma. In conclusion, D2-40 antibody staining may be useful as an adjunct in detecting LVI in invasive lobular carcinoma, especially in node-negative patients with the classic variant of invasive lobular carcinoma