Ross S. Basch

Amniotic fluid contains multipotent cells and could be a source of stem cells for clinical use. Amniotic fluid cells (AFCs) are made up of a heterogeneous population of fetal cells that can be retrieved during pregnancy without ethical concerns as it is a standard clinical procedure. Studies of proliferation, multipotent marker expression, differentiation, and gene expression were performed after culturing with dexamethasone, valproic acid, and magnesium sulfate. There were correlations between known drug effects on the human fetus and changes seen in human AFCs in culture, as well as previously undescribed observations in neural and chondrogenic inducibility. Gene expression profiles confirmed these observations. AFC culture may provide a novel method to evaluate pharmacological agents before clinical use in pregnancy.

Estrogen receptors (ER) play important roles in the development and progression of breast and ovarian cancers. ERs mediate transcriptional regulation through interaction with cofactors and binding to response elements within the regulatory elements of target genes. Here, we examined the expression and function of TBLR1/TBL1XR1, a core component of NCoR (nuclear receptor corepressor) and SMRT (silencing mediator of retinoic acid and thyroid receptor) corepressor complexes, in breast and ovarian cancers. We found that although TBLR1 is present in both the nucleus and cytoplasm of normal and neoplastic breast and ovarian cells, it is expressed at significantly higher levels in the nucleus of malignant breast and ovarian cells compared to benign cells. TBLR1 functions as an ER corepressor to inhibit ER-mediated transcriptional activation in both breast and ovarian cell lines, but it has no effect on androgen receptor (AR) mediated transcriptional activation in these cells. Furthermore, ectopic expression of nuclear TBLR1 in breast and ovarian cancer cells stimulates cell proliferation. The increased cell proliferation by nuclear TBLR1 is through both ER-independent and ER-dependent mechanisms as evidenced by increased growth in hormone-free medium and estrogen medium, as well as reduced growth with ER knockdown by siRNA. Nuclear TBLR1 overexpression also increased migration and invasion in both breast and ovarian cancer cells. Determining the functional relationship between TBLR1 and ER may provide insights to develop novel treatment strategies and improve response to hormonal therapy in breast and ovarian cancers.

// <![CDATA[ $('.header-date').hide();$('#titleAuthors').hide();$('#abstractHeader').hide(); // ]]> Garrett Daniels1, Xinmin Zhang2, Xuelin Zhong1, Larion Santiago1, Ling Hang Wang1, Xinyu Wu1, Jack Y. Zhang1, Fengxia Liang1, Xin Li3, Thomas A. Neubert4, Laurey Steinke5, Ying Shen1, Ross Basch1, Robert Schneider6, David E. Levy1, Peng Lee1, 7, 8, 9 1Department of Pathology, New York University School of Medicine, New York, NY, USA 2Department of Pathology and Laboratory Medicine, Hofstra North Shore-LIJ School of Medicine, Hempstead, NY, USA 3Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, USA 4Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA 5Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA 6Department of Microbiology and Molecular Pathogenesis, New York University School of Medicine, New York, NY, USA 7Department of Urology, New York University School of Medicine, New York, NY, USA 8NYU Cancer Institute, New York University School of Medicine, New York, NY, USA 9New York Harbor Healthcare System, New York University School of Medicine, New York, NY, USA Correspondence to: Peng Lee, email: peng.lee@nyumc.org Keywords: prostate cancer, subcellular localization, castration resistance, TBLR1, cvTBLR1 Received: November 03, 2015 Accepted: March 28, 2016 Published: April 26, 2016 ABSTRACT TBLR1/TBL1XR1, a core component of the nuclear receptor corepressor (NCoR) complex critical for the regulation of multiple nuclear receptors, is a transcriptional coactivator of androgen receptor (AR) and functions as a tumor suppressor when expressed in the nucleus in prostate. Subcellular localization of a protein is critical for its function, and although TBLR1, as a transcriptional cofactor, has been primarily viewed as a nuclear protein, many cells also express variable levels of cytoplasmic TBLR1 and its cytoplasmic specific functions have not been studied. Prostate cancer (PCa) cells express moderately higher level of cytoplasmic TBLR1 compared to benign prostate cells. When comparing androgen-dependent (AD) to androgen-independent (AI) PCa, AI cells contain very high levels of TBLR1 cytoplasmic expression and low levels of nuclear expression. Overexpression of cytoplasmic TBLR1 in AD cells inhibits apoptosis induced by androgen deprivation therapy, either in an androgen free condition or in the presence of bicalutamide. Additionally, we identified a cytoplasmic specific isoform of TBLR1 (cvTBLR1) approximately 5 kDa lower in molecular weight, that is expressed at higher levels in AI PCa cells. By immunoprecipitation, we purified cvTBLR1 and using mass spectrometry analysis combined with N-terminal TMPP labeling and Edman degradation, we identified the cleavage site of cvTBLR1 at amino acid 89, truncating the first 88 amino acids of the N-terminus of the full length protein. Functionally, cvTBLR1 expressed in the cytoplasm reduced apoptosis in PCa cells and promoted growth, migration, and invasion. Finally, we identified a nuclear export signal sequence for TBLR1 cellular localization by deletion and site-directed mutagenesis. The roles of TBLR1 and cvTBLR1 provide novel insights into the mechanism of castration resistance and new strategies for PCa therapy.

Amniotic fluid cells (AFC) from 2

Objective: The placenta of mid-gestation mice is a known rich source of hematopoietic stem cells. We hypothesized that it is also a source of other multipotent stem cells. Methods: We isolated fetal cells from the murine placenta across the second half of gestation and characterized their expression of surface antigens known to be associated with mesenchymal stem cells (MSCs) on a subset of hematopoietic lineage-negative cells. Using real-time reverse-transcriptase quantitative polymerase chain reaction, we also evaluated the expression of intracellular transcription factors (TFs) known to be associated with renal development and/or multipotent stem cells. Results: Cell phenotypes with surface marker and TF expression consistent with multipotent stem cells of a mesenchymal lineage as well as renal cell progenitors were found in the placenta. The expression of MSC and renal progenitor surface markers varied throughout gestation, but was highest on E12–15 where such cells represented a small but significant percentage of the population. Of the studied TFs, 10 of 11 renal TFs were found at moderate to high levels, and all stem cell TFs were found. Conclusion: The mid-gestation murine placenta may serve as a source of multipotent stem cells and also contains cells which may be renal cell progenitors.

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 β-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 (Pin 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. Abstract 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 β-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 (Pin 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.