Faculty Bibliography

The androgen receptor (AR) in stromal cells contributes significantly to the development and growth of prostate during fetal stages as well as during prostate carcinogenesis and cancer progression. During prostate development, stromal AR induces and promotes epithelial cell growth, as observed from tissue recombinant and mouse knockout studies. During prostate carcinogenesis and progression, the stromal cells begin to lose AR expression as early as at the stage of high-grade prostatic intraepithelial neoplasia. The extent of loss of stromal AR is directly proportional to the degree of differentiation (Gleason grade) and progression of prostate cancer (PCa). Co-culture studies suggested that stromal AR inhibits the growth of malignant epithelial cells, possibly through expression of certain paracrine factors in the presence of androgens. This functional reversal of stromal AR, from growth promotion during fetal prostate development to mediating certain growth-inhibiting effects in cancer, explains to some extent the reason that loss of AR expression in stromal cells may be crucial for development of resistance to androgen ablation therapy for PCa. From a translational perspective, it generates the need to re-examine the current therapeutic options and opens a fundamental new direction for therapeutic interventions, especially in advanced PCa.

Androgen receptor (AR), a steroid hormone receptor, is critical for prostate cancer growth. However, activation of AR by androgens can also lead to growth suppression and differentiation. Transcriptional cofactors play an important role in this switch between proliferative and anti-proliferative AR target gene programs. Transducin beta-like-related protein 1 (TBLR1), a core component of the nuclear receptor corepressor complex, shows both corepressor and coactivator activities on nuclear receptors, but little is known about its effects on AR and prostate cancer. We characterized TBLR1 as a coactivator of AR in prostate cancer cells and determined that the activation is dependent on both phosphorylation and 19S proteosome. We showed that TBLR1 physically interacts with AR and directly occupies the androgen-response elements of the affected AR target genes in an androgen-dependent manner. TBLR1 is primarily localized in the nucleus in benign prostate cells and nuclear expression is significantly reduced in prostate cancer cells in culture. Similarly, in human tumor samples, the expression of TBLR1 in the nucleus is significantly reduced in the malignant glands compared with the surrounding benign prostatic glands (P<0.005). Stable ectopic expression of nuclear TBLR1 leads to androgen-dependent growth suppression of prostate cancer cells in vitro and in vivo by selective activation of androgen-regulated genes associated with differentiation (e.g. KRT18) and growth suppression (e.g. NKX3-1), but not cell proliferation of the prostate cancer. Understanding the molecular switches involved in the transition from AR-dependent growth promotion to AR-dependent growth suppression will lead to more successful treatments for prostate cancer.

Transcriptional intermediary factor 1 gamma (Tif1gamma) (Ectodermin/PTC7/RFG7/TRIM33) is a transcriptional cofactor with an important role in the regulation of the TGFbeta pathway. It has been suggested that it competes with Smad2/Smad3 for binding to Smad4, or alternatively that it may target Smad4 for degradation, although its role in carcinogenesis is unclear. In this study, we showed that Tif1gamma interacts with Smad1/Smad4 complex in vivo, using both yeast two-hybrid and coimmunoprecipitation assays. We demonstrated that Tif1gamma inhibits transcriptional activity of the Smad1/Smad4 complex through its PHD domain or bromo-domainin pancreatic cells by luciferase assay. Additionally, there is a dynamic inverse relationship between the levels of Tif1gamma and Smad4 in benign and malignant pancreatic cell lines. Overexpression of Tif1gamma resulted in decreased level of Smad4. Both overexpression and knockdown of Tif1gamma resulted in growth inhibition in both benign and cancerous pancreatic cell lines, attributable to a G2-phase cell cycle arrest, but only knockdown of Tif1gamma reduces tumor cell invasiveness in vitro. Our study demonstrated that imbalanced expression of Tif1gamma results in inhibition of pancreatic ductal epithelial cell growth. In addition, knockdown of Tif1gamma may inhibit tumor invasion. These data suggest that Tif1gamma might serve as a potential therapeutic target for pancreatic cancer.

Introduction: Although HER2 and ER pathways are predominant pathways altered in breast cancer, it is now well accepted that many other signaling pathways are also involved in the pathogenesis of breast cancer. The understanding of these additional pathways may assist in identifying new therapeutic approaches for breast cancer. Methods: 13 invasive ductal carcinoma tissues and 5 benign breast tissues were analyzed for the mRNA expression level of 1243 cancer pathway-related genes using SmartChip (WaferGen, CA), a real-time PCR-base method. In addition, the levels of 131 cancer pathway-related proteins and phosphoproteins in 33 paired breast cancers were measured using our innovative Protein Pathway Array. Results: Out of 1,243 mRNAs, 68.7% (854) were detected in breast cancer and 395 mRNAs were statistically significant (fold change >2) between benign and cancer tissues. Of these mRNAs, 105 only expressed in breast cancer tissues and 33 mRNAs only expressed in normal breast tissues. Out of 131 proteins and phosphoproteins, 68% (89) were detected in cancer tissues and 57 proteins were significantly differentiated between tumor and normal tissues. Interestingly, only 3 genes (CDK6, Vimentin and SLUG) showed decreases in both protein and mRNA. Six proteins (BCL6, CCNE1, PCNA, PDK1, SRC and XIAP) were differentially expressed between tumor and normal tissues but no differences were observed at mRNA levels. Analyses of mRNA and protein data using Ingenuity Pathway Analysis showed more than 15 pathways were altered in breast cancer and 6 of which were shared between mRNAs and proteins, including p53, IL17, HGF, NGF, PTEN and PI3K/AKT pathways. Conclusions: There is a broad dysregulation of various pathways in breast cancer both at protein levels and mRNA levels. It is important to note that mRNA expression does not correlate with protein level, suggesting different regulation mechanisms between proteins and mRNAs.

BACKGROUND: Recently there has been an increased interest in the role of tumor-associated stroma in prostate tumorigenesis, but little is known about the respective roles of stomal ERalpha and ERbeta in prostate cancer (PCa). This study characterizes the expression patterns of ERalpha and ERbeta in tumor-associated stroma in association with various clinicopathological factors of importance in PCa prognosis and treatment. DESIGN: Immunohistochemistry was performed using antibodies against ERalpha and ERbeta to characterize their expression patterns in PCa tissue. Stromal ER levels (ERalpha and ERbeta) on tissue sections (n=47), were compared between tumor associated stroma and adjacent benign associated stroma. Immunohistochemistry was also performed on a PCa tissue microarray (TMA) (n=177) to correlate stromal expression with various clinicopathological parameters. The levels of ER nuclear expression were scored semi-quantitatively. RESULTS: The expression levels of both ERalpha and ERbeta were significantly lower in tumor-associated stroma than stroma surrounding benign prostatic glands on the same tissue section (ERalpha: p<0.01; ERbeta: p=0.01). When correlated with clinicopathological factors, the level of ERalpha expression in tumor-associated stroma showed a positive correlation with Gleason score (R(2)=0.8638). The expression of ERalpha was higher in PCa with advanced tumor stage (p=0.05) and not significantly different in extraprostatic extension (p>0.05). The level of ERbeta expression in tumor-associated stroma was decreased in patients older than 60 years compared to younger patients (p=0.01). CONCLUSION: This study demonstrates significant down-regulation of ERalpha and ERbeta expression in the tumor-associated stroma of PCa. However, the level of ERalpha expression in tumor-associated stroma shows a positive correlation with cancer differentiation and tumor stage.

BACKGROUND: The goal of the Prostate Cancer Biorepository Network (PCBN) is to develop a biorepository with high-quality, well-annotated specimens obtained in a systematic, reproducible fashion using optimized and standardized protocols, and an infrastructure to facilitate the growth of the resource and its wide usage by the prostate cancer research community. An emerging area of concern in the field of prostate cancer biobanking is an apparent shift in the proportion of surgical procedures performed for prostate cancer treatment from radical retropubic prostatectomy (RRP) to robot-assisted laparoscopic prostatectomy (RALP). Our study aimed to determine the potential impact of the RALP procedure on the detection of known prostate cancer biomarkers, and the subsequent suitability of RALP-derived specimens for prostate cancer biomarker studies. METHODS: DNA and RNA were extracted from RRP and RALP specimens. Quality assessment was conducted using spectrophotometric analysis and RNA was analyzed for RNA integrity number (RIN) and by real-time reverse-transcription PCR (qRT-PCR) for racemase, hepsin, ERG, TMPRSS2-ERG gene fusions, and the microRNAs miR-26a, miR-26b, miR-141, and miR-221. RESULTS: We demonstrate that extraction of derivatives from frozen tissues from RRP and RALP specimens yields samples of equally high quality as assessed by spectrophotometric and RIN analysis. Likewise, expression levels of genes analyzed by qRT-PCR did not differ between RRP and RALP-derived tissues. CONCLUSIONS: Our studies indicate that samples obtained from RALP specimens may be suitable for prostate cancer biomarker studies-an important finding given the current shift in surgical procedures for prostate cancer treatment. Prostate 9999: XX-XX, 2013. (c) 2013 Wiley Periodicals, Inc.

Bone morphogenetic protein (BMP) signaling has emerged as an important regulator of sensory neuron development. Using a three-generation forward genetic screen in mice we have identified Megf8 as a novel modifier of BMP4 signaling in trigeminal ganglion (TG) neurons. Loss of Megf8 disrupts axon guidance in the peripheral nervous system and leads to defects in development of the limb, heart, and left-right patterning, defects that resemble those observed in Bmp4 loss-of-function mice. Bmp4 is expressed in a pattern that defines the permissive field for the peripheral projections of TG axons and mice lacking BMP signaling in sensory neurons exhibit TG axon defects that resemble those observed in Megf8 (-/-) embryos. Furthermore, TG axon growth is robustly inhibited by BMP4 and this inhibition is dependent on Megf8. Thus, our data suggest that Megf8 is involved in mediating BMP4 signaling and guidance of developing TG axons. DOI:http://dx.doi.org/10.7554/eLife.01160.001.

Androgen receptor (AR) plays an important role in the tumorigenesis and progression of prostate cancer (PCa), and is the primary therapeutic target for PCa treatment. AR activity can be regulated via phosphorylation at multiple phosphorylation sites within the protein. Modifications by phosphorylation alter AR function, including its cellular localization, stability and transcriptional activity, ultimately leading to changes in cancer cell biology and disease progression. Here we present a brief overview of AR phosphorylation sites in PCa, focusing on functional roles of phospho-AR (p-AR) species, relevance in PCa disease progression, and potential as biomarkers and/or therapeutic targets through the use of kinase inhibitors. Additionally, recent evidence has shown the important role of AR activity in the cancer associated stroma on PCa growth and progression. The phosphorylation status of epithelial and stromal AR may be distinct; however, the current data available on stromal AR phosphorylation is limited. Further research will determine global view on the synergistic effects of phosphorylation across multiple AR sites in both epithelial and stromal cells and validate whether together they can be used as prognostic markers and/or effective therapeutic targets for PCa.

Tubulocystic renal cell carcinoma (TC-RCC) is a rare renal tumor composed of well-differentiated tubules and cysts lined by neoplastic cells with eosinophilic cytoplasm and prominent nucleoli. The origin of the tumor cells is still controversial. TC-RCC typically arises unilaterally. Involvement of both kidneys by multifocal TC-RCC has not been reported. In this study we report the first case of bilateral and multifocal TC-RCC. Immunohistochemical, cytogenetic and ultrastructural studies suggest TC-RCC is closely related to papillary RCC.