Faculty Bibliography

In previous studies, we have demonstrated that adenosine and its receptors play a role in hepatic fibrosis. Here, we review evidence that toxin-induced increases in hepatic adenosine concentrations are generated from adenine nucleotides by the action of ecto-5'nucleotidase and thus that adenosine-mediated, toxin-induced hepatic fibrosis depends on extracellular conversion of adenine nucleotides to adenosine

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

Thyroid-specific transcription factors, Pax8, TTF-1, and TTF-2, are crucial for thyroid organogenesis and differentiation. Compared with TTF-1, the other two markers have scarcely been investigated in surgical pathology. The goal of this study is to evaluate the expressions of these markers in thyroid tumors of the full spectrum of differentiation, with special emphasis on anaplastic carcinomas. A total of 94 cases of thyroid neoplasms were studied: 17 papillary carcinomas, 18 follicular adenomas, 16 follicular carcinomas, 7 poorly differentiated carcinomas, 28 anaplastic carcinomas, and 8 medullary carcinomas. Immunostains for these three markers were performed. The antibodies to Pax8 and TTF-2 were also applied on 147 lung carcinomas as well as a variety of normal tissues and malignant tumors. All three markers were seen in papillary carcinomas, follicular adenomas and carcinomas, and poorly differentiated carcinomas in a diffuse manner, whereas their expressions in medullary carcinomas were variable. Pax8 was expressed in 79% of anaplastic carcinomas to a variable extent, whereas TTF-1 and TTF-2 were seen only in 18 and 7% of anaplastic carcinomas, respectively. TTF-2 was negative in all other neoplastic and non-neoplastic tissues including those of the lung. Pax8 was expressed in renal tubules, fallopian tubes, ovarian inclusion cysts, and lymphoid follicles as well as renal carcinoma, nephroblastoma, seminoma, and ovarian carcinoma, but not in normal tissue and carcinomas of the lung. Pax8 is a useful marker for the diagnosis of anaplastic carcinomas, particularly when the differential diagnosis includes pulmonary carcinoma. In differentiated thyroid neoplasms, no significant difference in expression was seen in all the three transcription factors.Modern Pathology advance online publication, 14 December 2007; doi:10.1038/modpathol.3801002

ARA70 is a coactivator of androgen receptor (AR), a ligand-dependent transcription factor that plays an important role in prostate cancer. There are 2 variants of ARA70, the full length 70 kd ARA70alpha isoform and the internally spliced 35 kd ARA70beta isoform. Recent studies have suggested different expression and roles of the 2 isoforms in several endocrine malignancies, including prostate, breast, and ovarian cancers. To study the roles of these isoforms in cancers, we produced isoform-specific polyclonal antibodies. The anti-ARA70alpha antibody was raised in rabbits against 326 amino acid peptide corresponding to the internal deletion missing from ARA70beta (ARA70id), whereas the anti-ARA70beta antibody was raised against 18 amino acid polypeptide spanning the splice junction, with Gln-Gln motif unique to ARA70beta. The antisera were affinity purified on CNBr-activated sepharose 4B, and their specificity tested against bacterially expressed, Ni-column-purified ARA70alpha, ARA70beta, and ARA70id. The anti-ARA70alpha antibody recognized ARA70alpha and ARA70id, but not ARA70beta. The anti-ARA70beta antibody was specific to ARA70beta and did not cross-react with ARA70alpha or ARA70id. We then used these antibodies to detect ARA70 isoforms in crude extracts made of prostate cancer cell lines and performed immunohistochemical localization of these proteins in prostate tissues. ARA70beta localized to the cytosol, whereas ARA70alpha was found in the nucleus, supporting the notion of their dissimilar functions

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