Interleukin 13 (IL-13)-regulated expression of the chondroprotective metalloproteinase ADAM15 is reduced in aging cartilage

Objective

The adamalysin metalloproteinase 15 (ADAM15) has been shown to protect against development of osteoarthritis in mice. Here, we have investigated factors that control ADAM15 levels in cartilage.

Design

Secretomes from wild-type and Adam15^−/− chondrocytes were compared by label-free quantitative mass spectrometry. mRNA was isolated from murine knee joints, either with or without surgical induction of osteoarthritis on male C57BL/6 mice, and the expression of Adam15 and other related genes quantified by RT-qPCR. ADAM15 in human normal and osteoarthritic cartilage was investigated similarly and by fluorescent immunohistochemistry. Cultured HTB94 chondrosarcoma cells were treated with various anabolic and catabolic stimuli, and ADAM15 mRNA and protein levels evaluated.

Results

There were no significant differences in the secretomes of chondrocytes from WT and Adam15^−/− cartilage. Expression of ADAM15 was not altered in either human or murine osteoarthritic cartilage relative to disease-free controls. However, expression of ADAM15 was markedly reduced upon aging in both species, to the extent that expression in joints of 18-month-old mice was 45-fold lower than in that 4.5-month-old animals. IL-13 increased expression of ADAM15 in HTB94 ​cells by 2.5-fold, while modulators of senescence and autophagy pathways had no effect. Expression of Il13 in the joint was reduced with aging, suggesting this cytokine may control ADAM15 levels in the joint.

Conclusion

Expression of the chondroprotective metalloproteinase ADAM15 is reduced in aging human and murine joints, possibly due to a concomitant reduction in IL-13 expression. We thus propose IL-13 as a novel factor contributing to increased osteoarthritis risk upon aging.

MEK is a promising target in the basal subtype of bladder cancer

While many resources exist for the drug screening of bladder cancer cell lines in 2D culture, it is widely recognized that screening in 3D culture is more representative of in vivo response. Importantly, signaling changes between 2D and 3D culture can result in changes to drug response. To address the need for 3D drug screening of bladder cancer cell lines, we screened 17 bladder cancer cell lines using a library of 652 investigational small-molecules and 3 clinically relevant drug combinations in 3D cell culture. Our goal was to identify compounds and classes of compounds with efficacy in bladder cancer. Utilizing established genomic and transcriptomic data for these bladder cancer cell lines, we correlated the genomic molecular parameters with drug response, to identify potentially novel groups of tumors that are vulnerable to specific drugs or classes of drugs. Importantly, we demonstrate that MEK inhibitors are a promising targeted therapy for the basal subtype of bladder cancer, and our data indicate that drug screening of 3D cultures provides an important resource for hypothesis generation.

Abstract A16: Characterization of ErbB family expression in intratibial bladder cancer xenografts: Considerations for preclinical modeling

Background: Approximately 40% of patients with distant metastatic bladder cancer are diagnosed with bone metastases and a dismal 5-year survival rate of less than 10%. The bone has long been thought to act as “soil” for metastatic cells to “seed,” likely due to the favorable, albeit complex microenvironment that comprises various cell types and growth factors. A study by The Cancer Genome Atlas (TCGA) profiling 405 muscle-invasive bladder cancers reported alterations of the receptor tyrosine kinase pathway in 20% of these patients. This included amplification of EGFR in 9% of cases, mutation or amplification of ERBB2 in 9% of cases, and mutation of ERBB3 in 6% of cases. The purpose of this study was to correlate the expression of ErbB family members in human bladder cancer cell lines with their ability to grow as intratibial xenografts in immune-compromised mice.

Methods: We performed intratibial injections with six established human bladder cancer cell lines in 22 NSG mice and we allowed these xenografts to grow for five weeks. Four cell lines expressed luciferase and were measured for bioluminescent signals at multiple time points. The resulting formalin-fixed, paraffin-embedded tibiae were processed for immunohistochemistry (IHC) which utilized human specific antibodies to CK8, EGFR, HER2, Ki-67, and uroplakin.

Results: The four luciferase-expressing cell lines exhibited increasing bioluminescent signal over the duration of the study (n=14). Five cell lines had positive human anti-Ki-67 staining in the tibia, confirming their growth in the bone after the intratibial injection. All five cell lines maintained expression, and in certain cases overexpression, of EGFR and HER2 in the intratibial xenografts. We observed an 87.5% take rate (n=16) in a subset of bladder cell lines (5 out of 6) and only the UM-UC-12 cell line exhibiting a 0% take rate (n=6).

Conclusion: The high take rate of these five cell lines in the tibia exceeded that of previous studies (25-50%), indicating that the take rate is cell line dependent. Characterizing the ErbB expression profile of individual cell lines in the tibia xenograft model is an important consideration before using these xenografts as a preclinical model. Furthermore, ubiquitous expression of ErbB receptors in tibiae xenografts highlights the importance of growth factor signaling in metastatic bladder cancer and the potential for ErbB targeted therapy.

Citation Format: Luke J. Broses, Kathleen C. Day, Aaron M. Udager, Mark L. Day. Characterization of ErbB family expression in intratibial bladder cancer xenografts: Considerations for preclinical modeling [abstract]. In: Proceedings of the AACR Special Conference on Bladder Cancer: Transforming the Field; 2019 May 18-21; Denver, CO. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(15_Suppl):Abstract nr A16.

Abstract B35: Isolation and characterization of circulating tumor cells (CTCs) from bladder cancer patients using a highly sensitive graphene oxide-based microfluidic device (GO chip)

Introduction: A critical research topic in bladder cancer is determining the key regulators in the progression from noninvasive tumor to invasive and ultimately metastatic disease. Although patients with noninvasive bladder cancer can be treated through transurethral resection of bladder tumor and have a high survival rate (~95%), noninvasive bladder tumors recur in 50%-70% of cases. Of these, 10-15% of cases progress to invasive disease. Circulating tumor cells (CTCs) represent the transitional phase of progression between lymphovascular intravasation and distant metastases. Molecular profiling of these CTCs, beyond enumeration, can inform the molecules/pathways important in the invasion process, and potentially help unravel the mechanism of metastasis and provide new targets for therapy. Here we report the application of a highly sensitive graphene oxide-based microfluidic device to isolate and characterize CTCs from bladder cancer patients for the expression of markers implicated in an invasive phenotype.

Methods: An anti-EpCAM and anti-EGFR biotinylated antibody cocktail was immobilized onto the graphene oxide chip (GO chip) to capture CTCs from whole blood. In patient samples, immunofluorescence staining for DAPI (nuclei), cytokeratin (cancer cell marker), EGFR and HER2 (markers of invasive phenotype), and CD45 (white blood cell marker) was used to enumerate CTCs. Cells with a DAPI+CK+CD45- phenotype were counted as CTCs. Blood samples from ten metastatic bladder cancer patients and two healthy controls were processed, stained, and analyzed.

Results: CTCs were found in 10/10 (100%) patients, with an average of 17.70 cells/mL (s = 10.69 cells/mL). 9/10 patients exhibited CTCs that express EGFR, but only one patient had one CTC express HER2.

Conclusion: The antibody-functionalized GO chips were able to successfully capture and enable characterization of CTCs from metastatic bladder cancer patients. EGFR potentially plays an important role in the vascular invasion process.

Citation Format: Zeqi Niu, Molly A. Kozminsky, Kathleen C. Day, Phillip L. Palmbos, Mark L. Day, Sunitha Nagrath. Isolation and characterization of circulating tumor cells (CTCs) from bladder cancer patients using a highly sensitive graphene oxide-based microfluidic device (GO chip) [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr B35.

Multiparameter urine analysis for quantitative bladder cancer surveillance of orthotopic xenografted mice

The human-derived orthotopic xenograft mouse model is an effective platform for performing in vivo bladder cancer studies to examine tumor development, metastasis, and therapeutic effects of drugs. To date, the surveillance of tumor progression in real time for orthotopic bladder xenografts is highly dependent on semi-quantitative in vivo imaging technologies such as bioluminescence. While these imaging technologies can estimate tumor progression, they are burdened with requirements such as anesthetics, specialized equipment, and genetic modification of the injected cell line. Thus, a convenient and non-invasive technology to quantitatively monitor the growth of bladder cancer in orthotopic xenografts is highly desired. In this work, using a microfluidic chemiluminescent ELISA platform, we have successfully developed a rapid, multiparameter urine-based and non-invasive biomolecular prognostic technology for orthotopic bladder cancer xenografts. This method consists of two steps. First, the concentrations of a panel of four urinary biomarkers are quantified from the urine of mice bearing orthotopic bladder xenografts. Second, machine learning and principal component analysis (PCA) algorithms are applied to analyze the urinary biomarkers, and subsequently, a score is assigned to indicate the tumor growth. With this methodology, we have quantitatively monitored the orthotopic growth of human bladder cancer that was inoculated with low, medium, and high cancer cell numbers. We also employed this method and performed a proof of principle experiment to examine the in vivo therapeutic efficacy of the EGFR inhibitor, dacomitinib.

A surgical orthotopic approach for studying the invasive progression of human bladder cancer

The invasion of bladder cancer into the sub-urothelial muscle and vasculature are key determinants leading to lethal metastatic progression. However, the molecular basis is poorly understood, partly because of the lack of uncomplicated and reliable models that recapitulate the biology of locally invasive disease. We developed a surgical grafting technique, characterized by a simple, rapid, reproducible and high-efficiency approach, to recapitulate the pathobiological events of human bladder cancer invasion in mice. This technique consists of a small laparotomy and direct implantation of human cancer cells into the bladder lumen. Unlike other protocols, it does not require debriding of the urothelial lining, injection into the bladder wall, specialized imaging equipment, bladder catheterization or costly surgical equipment. With minimal practice, the procedure can be executed in <10 min. Tumors develop with a high take rate, and most cell lines exhibit local invasion within 4 weeks of implantation.

Identification of gene expression determinants of radiosensitivity in bladder cancer (BCa) cell lines

470

Background: Trimodality therapy with TURBT followed by concurrent chemoradiation is an alternative to cystectomy in selected patients with muscle invasive BCa. Identifying genetic determinants of radiation response may help select patient for organ-sparing treatments with curative intent. Methods: Molecular characterization of 20 cell lines was previously performed, including mutation analysis, CNA (high density SNP arrays) and gene expression (RNAseq). Cell line identity was authenticated by genomic fingerprinting. We performed colony forming assays (CFA) and cumulative survival was quantified using the area under the cell survival curve (AUC, range 0-8Gy) to create a radiosensitivity index. Pre and post-radiation proliferative capacity was determined by cell titer glo (CTG) assay. Gene (R v3.5.1) and network (Ingenuity Pathyway Analysis) level expression differences were determined as a function of AUC to identify biologically relevant associations with radiation response. Results: Of 20 cell lines (7 basal, 13 luminal subtype), both CFA and CTG data was successfully obtained for 13 cell lines (6 basal, 7 luminal) treated with high dose rate (HDR) radiation. AUCs for the colony forming assay (CFA) survival curves ranged 1.79-3.27. RNAseq identified 18,634 unique transcripts mapping to distinct loci and 196 genes were identified with AUC correlation p values <0.01 (FDR <0.5, mean FPKM>0.5). These genes were strongly enriched for membership in the peroxisome proliferator (PPAR) pathway (IPA, p = 9.40E-03) and STAT3 pathway (IPA, p = 1.56E-3). Validation studies confirmed PPARγ, ICAM2, JAK3, IL1B, OAS1 and OAS2 genes to be associated with differential response to radiation, with expression upregulated in radio-resistant cells. A basal subtype was strongly associated with a radiosensitive phenotype (Chi-Squared χ2 p=0.0083). Conclusions: BCa radio-sensitivity was associated with baseline gene expression differences in vitro. The basal subtype and repression of either the PPAR or STAT3 pathways predicted increased radiosensitivity. This study nominates candidate biomarkers for mechanistic studies and clinical validation in BCa.

3-D Cell Culture System for Studying Invasion and Evaluating Therapeutics in Bladder Cancer

Bladder cancer is a significant health problem. It is estimated that more than 16,000 people will die this year in the United States from bladder cancer. While 75% of bladder cancers are non-invasive and unlikely to metastasize, about 25% progress to an invasive growth pattern. Up to half of the patients with invasive cancers will develop lethal metastatic relapse. Thus, understanding the mechanism of invasive progression in bladder cancer is crucial to predict patient outcomes and prevent lethal metastases. In this article, we present a three-dimensional cancer invasion model which allows incorporation of tumor cells and stromal components to mimic in vivo conditions occurring in the bladder tumor microenvironment. This model provides the opportunity to observe the invasive process in real time using time-lapse imaging, interrogate the molecular pathways involved using confocal immunofluorescent imaging and screen compounds with the potential to block invasion. While this protocol focuses on bladder cancer, it is likely that similar methods could be used to examine invasion and motility in other tumor types as well.

Molecular Correlates of In Vitro Responses to Dacomitinib and Afatinib in Bladder Cancer

Background:

The HER family of proteins (EGFR, HER2, HER3 and HER4) have long been thought to be therapeutic targets for bladder cancer, but previous clinical trials targeting these proteins have been disappointing. Second generation agents may be more effective.

Objective:

The aim of this study was to evaluate responses to two second-generation irreversible tyrosine kinase inhibitors, dacomitinib and afatinib, in bladder cancer cell lines.

Methods:

Cell lines were characterized by targeted next generation DNA sequencing, RNA sequencing, western blotting and flow cytometry. Cell survival responses to dacomitinib or afatinib were determined using (3-[4,5-dimethylthioazol-2-yl]-2,5-diphenyl tetrazolium bromide) (MTT) or [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) and phenazine methosylfate (PMS) cell survival assays.

Results:

Only two cell lines of 12 tested were sensitive to afatinib. Sensitivity to afatinib was significantly associated with mutation in either HER2 or HER3 (p < 0.05). The two cell lines sensitive to afatinib were also responsive to dacomitinib ralong with an additional 4 other cell lines out of 16 tested. No characteristic was associated with dacomitinib sensitivity. Molecular profiling demonstrated that only two genes were high in both afatinib and dacomitinib sensitive cells. Further rhigher expression of RAS pathway genes was noted for dacomitinib responsive cells.

Conclusions:

This study confirms that cell line screening can be useful in pre-clinical evaluation of targeted small molecule inhibitors and suggests that compounds with similar structure(s) and target(s) may have distinct sensitivity profiles. Further rcombinational targeting of additional molecularly relevant pathways may be important in enhancing responses to HER targeted agents in bladder cancer.

Impact of a timed-release FSH treatment from 2 to 6 months of age in bulls II: Endocrinology, puberty attainment, and mature sperm production in Holstein bulls

The use of genomic testing in the cattle industries has renewed an interest in hastening bull puberty. In prepubertal males, FSH facilitates Sertoli cell proliferation and testis maturation. The aim of this study was to determine the effect of prepubertal administration of a timed-release FSH (delivered in a hyaluronan solution) on hormone secretion, puberty attainment, and mature sperm production in Holstein bulls in an AI center. Bulls (n = 29) were randomly assigned to one of two treatment groups based on birth date and pedigree. Beginning at 62 days of age (Day 62), bulls were injected im every 3.5 days with either 30 mg FSH (Folltropin-V; NIH-FSH-P1 units) in a 2% hyaluronan solution (FSH-HA, n = 17) or saline (control, n = 12) until Day 170.5. Blood samples to assess FSH, activin A, and testosterone were collected prior to each treatment. Scrotal circumference (SC) and BW were measured monthly. Puberty assessment (ability to ejaculate 5 × 10⁷ sperm, 10% motile) was initiated at Day 244. Average mature daily sperm production (3× wk collection, combined 2 ejaculates) was assessed from Day 571-627. In blood collected every 3.5 days, FSH concentrations within FSH-HA bulls were increased (P < 0.05) over initial Day 62 concentration from Day 93.5-170.5. Concentrations of FSH did not differ between treatments from Day 62-93.5, but were greater (P < 0.05) in FSH-HA than control bulls from Day 97-170.5. Concentrations of activin A assessed for Day 62, 86.5, 107.5, 139, and 170.5 were greater (P < 0.05) in FSH-HA than control bulls on Day 86.5 and 107.5. Treatments did not differ (P > 0.1) in testosterone, BW, or SC. FSH-HA bulls attained puberty at a younger age than control bulls (278 ± 7.7 vs. 303 ± 9.1 days of age, P < 0.05), but mature daily sperm production was not different when measured from Day 571-627 (average 5.84 ± 0.11 billion cells/day, P = 0.5). In summary, FSH administration every 3.5 days from Day 62-170.5 resulted in an increase in FSH concentration beginning at 97 days of age and a hastened age of puberty. We propose this exogenous FSH delivered in hyaluronan initiates a positive feedback loop that includes an increase in activin A production observed on Day 86.5 and 107.5. However, differences in mature sperm production were not realized in this experiment.

Abstract LB-B08: Validation of ADAM15 as a therapeutic target in invasive bladder cancer cells

Introduction: Advanced bladder cancer is a deadly and costly disease with locally invasive tumors carrying the worst prognosis for progression and mortality. The ADAM15 membrane disintegrin is key regulator in the invasive processes. Our previous studies demonstrated that increased expression of ADAM15 mRNA and protein is significantly associated with the local submucosal and lymphovascular invasion (LVI) and metastatic progression of human bladder cancer. Additionally, ADAM15 mediates integrin binding and has specifically been linked to the tumor-associated β1 integrins. This study aims to understand the ADAM15 disintegrin function and its potential as target in invasive bladder cancer. Methods: Collagen I represents the bulk of the submucosal matrix in the bladder and likely contributes to bladder cancer progression. Here, we developed a 3-dimensional (3D) culture system in collagen I to evaluate the phenotype of a panel of invasive bladder cancer cells. Furthermore, we developed a cyclic hexapeptide based on ADAM15 structure (adamatide), which can bind to the β1 integrin binding site; a rabbit polyclonal antibody against ADAM15 disintegrin domain (anti-A15DD); and, human recombinant ADAM15 disintegrin domain (hrA15DD) to compete with the endogenous protein. The effect of these inhibitors was evaluated on our 3D systems and compared to previously stablished ADAM15 knockdowns (shADAM15) in bladder cancer cell lines. Results: We assessed ADAM15 expression by Western blotting and immunofluorescence imaging in a panel of invasive bladder cancer cells. ADAM15 was highly expressed in the invasive cell lines, including UM-UC6 and UM-UC9. However, when cells were grown on plastic, ADAM15 was exclusively localized in cytoplasmic vesicles. On the contrary, when using 3D collagen cultures, ADAM15 translocated to filopodium-like protrusions (FLPs) on the cell membrane. Confocal imaging showed both co-expression and localization of ADAM15 and integrin β1, at the cellular level in collagen systems. These findings were validated by IHC of novel orthotopic models of bladder cancer, showing that both molecules localized at the muscle invasive front of the tumors as well as tumor emboli (LVI). Cells grown in collagen also presented increased FLP formation, invasion and proliferation rate when compared with those in plastic. Pharmacological inhibition of ADAM15 disintegrin activity or shADAM15 decreased cell attachment to collagen, invasion and FLPs in our 3D systems. Cells proliferation was also inhibited. Decreased cell viability was observed after treatment with the inhibitors on the 3D cultures. Early intracellular signaling events associated with these observations included inhibition of the FAK-Akt pathway. Conslusions: Our results show that ADAM15 has a key role in the invasive phenotype of bladder cancer cells via integrin β1 and FAK-Akt pathway. Thus, inhibition of ADAM15 activity represents a novel in vitro targeting strategy for bladder cancer

Citation Format: Guadalupe Lorenzatti Hiles, Angelica L. Cates, John R. Rubin, Matthew C. Winkler, Hannah L. Briggs, Mark L. Day. Validation of ADAM15 as a therapeutic target in invasive bladder cancer cells [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr LB-B08.

Abstract 1731: Analysis of prostate cancer circulating tumor cells at the mRNA and protein level using a microfluidic graphene oxide chip

While the relative five-year survival rate for men with localized prostate cancer is nearly 100%, it plummets to 28% in the case of distant metastases. This underscores the importance of investigating those cells able to spread and form these metastases: circulating tumor cells (CTCs). Though rare and surrounded by other blood cells, CTCs can be isolated using the sensitive nanomaterial-based microfluidic technology the graphene oxide (GO) Chip. Whole blood samples from 54 prostate cancer patients were obtained with consent and processed on parallel chips for immunofluorescence and RNA analysis. All of the samples were analyzed for CTC enumeration, where captured cells were stained for cytokeratin 7/8 (CK), CD45, and DAPI. CTCs were identified as DAPI+/CK+/CD45- cells. CTCs were detected in all of the samples. Interestingly, 25 samples showed CTC clusters ranging from 2-10 CTCs per cluster. To explore the potential role of EGFR in metastatic progression and CTC survival, a subset of samples was also assayed for EGFR expression with 9/10 samples showing EGFR+ CTCs. RNA extracted from a parallel device was reverse transcribed to cDNA. The cDNA was analyzed via qPCR for expression levels of 96 genes of interest, including housekeeping genes; epithelial and mesenchymal genes; oncogenes and tumor suppressor genes; prostate specific genes; extracellular matrix and inflammatory genes; and others. The results show our ability to examine RNA from CTCs to examine the role of relevant pathways in the cells in transit. With analysis capabilities at both the RNA and protein levels, the GO Chip is an example of a clinically relevant microfluidic technology.

Citation Format: Molly Kozminsky, Kathleen C. Day, Guadalupe Lorenzatti Hiles, Shamileh Fouladdel, Ebrahim Azizi, Mark L. Day, Todd Morgan, Sunitha Nagrath. Analysis of prostate cancer circulating tumor cells at the mRNA and protein level using a microfluidic graphene oxide chip [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1731. doi:10.1158/1538-7445.AM2017-1731

Impact of a timed-release follicle-stimulating hormone treatment from one to three months of age on endocrine and testicular development of prepubertal bulls

In prepubertal bulls, FSH facilitates testis maturation and a transient proliferation of Sertoli cells. Two experiments examined the effects of exogenous FSH on hormone secretion and testis development in Angus bulls. Exogenous FSH treatment consisted of an intramuscular injection (i.m.) of 30 mg FSH (Folltropin-V) in a 2% hyaluronic acid solution (FSH-HA). In Exp. 1, bulls (50 ± 6.5 d of age) received either FSH-HA ( = 5) or saline (control; = 5) on d 50 and 53.5. Blood samples were collected via jugular venipuncture to assess FSH concentrations every 6 h for 24 h after treatment and every 12 h until 84 h. After each treatment, peripheral FSH concentrations were greater ( < 0.05) in the FSH-HA-treated bulls than in the control bulls 6 h after treatment and tended to be greater ( ≤ 0.08) 12 h after treatment. The FSH concentration from 18 to 84 h after treatment did not differ between treatments. In Exp. 2, bulls were treated with FSH-HA ( = 11) or saline (control; = 11) every 3.5 d from 35 to 91 ± 2 d of age. Blood samples were collected before each treatment to quantify FSH, testosterone, and activin A concentrations. Scrotal circumference (SC) and BW were measured weekly. Bulls were castrated at 93 ± 2 d of age. Seminiferous tubule diameter, testis composition, and the number of Sertoli cells per tubule cross section (GATA-4 positive staining) were determined from fixed and stained histological sections. Follicle-stimulating hormone concentrations within the FSH-HA-treated bulls increased ( < 0.05) on d 70 from prior sampling and remained elevated. The FSH concentration did not differ between treatments from 35 to 66.5 d of age but were greater ( < 0.05) in the FSH-HA-treated bulls than in the control bulls from 70 to 91 d of age. Serum concentration of activin A on d 35, 70, and 91 did not differ between treatments. The FSH-HA and control bulls did not differ ( > 0.1) in BW, SC, testis weight, testis volume, percent of parenchyma composed of tubules, tubule diameter, and concentration of testosterone. The number of Sertoli cells per tubule cross section was greater in the FSH-HA-treated bulls than in the control bulls (33.35 ± 0.9 vs. 28.27 ± 0.9 cells; ˂ 0.05). In summary, the FSH-HA treatment from 35 to 91 d of age resulted in increased endogenous FSH from 70 to 91 d and increased numbers of Sertoli cells at 93 d of age. Exogenous FSH altered endocrine mechanisms regulating endogenous FSH secretion and augmented Sertoli cell proliferation in young bulls, but this effect was apparently not caused by increased activin A concentration in the FSH-HA-treated bulls.

HER2 and EGFR Overexpression Support Metastatic Progression of Prostate Cancer to Bone

Activation of the EGF receptors EGFR (ErbB1) and HER2 (ErbB2) drives the progression of multiple cancer types through complex mechanisms that are still not fully understood. In this study, we report that HER2 expression is elevated in bone metastases of prostate cancer independently of gene amplification. An examination of HER2 and NF-κB receptor (RANK) coexpression revealed increased levels of both proteins in aggressive prostate tumors and metastatic deposits. Inhibiting HER2 expression in bone tumor xenografts reduced proliferation and RANK expression while maintaining EGFR expression. In examining the role of EGFR in tumor-initiating cells (TIC), we found that EGFR expression was required for primary and secondary sphere formation of prostate cancer cells. EGFR expression was also observed in circulating tumor cells (CTC) during prostate cancer metastasis. Dual inhibition of HER2 and EGFR resulted in significant inhibition of tumor xenograft growth, further supporting the significance of these receptors in prostate cancer progression. Overall, our results indicate that EGFR promotes survival of prostate TIC and CTC that metastasize to bone, whereas HER2 supports the growth of prostate cancer cells once they are established at metastatic sites. Cancer Res; 77(1); 74-85. ©2016 AACR.

ADAM15 Is Functionally Associated with the Metastatic Progression of Human Bladder Cancer

ADAM15 is a member of a family of catalytically active disintegrin membrane metalloproteinases that function as molecular signaling switches, shed membrane bound growth factors and/or cleave and inactivate cell adhesion molecules. Aberrant metalloproteinase function of ADAM15 may contribute to tumor progression through the release of growth factors or disruption of cell adhesion. In this study, we utilized human bladder cancer tissues and cell lines to evaluate the expression and function of ADAM15 in the progression of human bladder cancer. Examination of genome and transcriptome databases revealed that ADAM15 ranked in the top 5% of amplified genes and its mRNA was significantly overexpressed in invasive and metastatic bladder cancer compared to noninvasive disease. Immunostaining of a bladder tumor tissue array designed to evaluate disease progression revealed increased ADAM15 immunoreactivity associated with increasing cancer stage and exhibited significantly stronger staining in metastatic samples. About half of the invasive tumors and the majority of the metastatic cases exhibited high ADAM15 staining index, while all low grade and noninvasive cases exhibited negative or low staining. The knockdown of ADAM15 mRNA expression significantly inhibited bladder tumor cell migration and reduced the invasive capacity of bladder tumor cells through Matrigel^TM and monolayers of vascular endothelium. The knockdown of ADAM15 in a human xenograft model of bladder cancer inhibited tumor growth by 45% compared to controls. Structural modeling of the catalytic domain led to the design of a novel ADAM15-specific sulfonamide inhibitor that demonstrated bioactivity and significantly reduced the viability of bladder cancer cells in vitro and in human bladder cancer xenografts. Taken together, the results revealed an undescribed role of ADAM15 in the invasion of human bladder cancer and suggested that the ADAM15 catalytic domain may represent a viable therapeutic target in patients with advanced disease.

Autophagy inhibition (AI) as a novel treatment strategy in bladder cancer (BC)

449

Background: BC response to chemotherapy has reached a plateau; novel treatment targets are needed. Autophagy is an important protein degradation mechanism that may be involved in chemotherapy response/resistance. AI was shown to overcome drug resistance in preclinical studies, but has not been well studied in BC. We conducted comprehensive gene expression analysis in BC cell lines to define their autophagy pathway expression signatures. We then investigated the anti-tumor activity and pharmacodynamics (PD) of our novel autophagy inhibitor ROC-325 (superior to hydroxychloroquine) in preclinical BC models with high baseline autophagy levels. Methods: Baseline expression of autophagy-related genes was evaluated by RNASeq in 21 BC cell lines. Gene and protein expression of selected autophagy-related genes was confirmed by qRT-PCR and immunoblot. PD effects of ROC-325 on lysosomal protease cathepsin D (CTSD) were assessed in 2 selected BC cell lines: UM-UC-3 (mesenchymal), UM-UC-6 (epithelial). The ability of ROC-325 (72 hour treatment) to augment gemcitabine (G) and cisplatin (C) activity in the 2 cell lines was evaluated by MTT assay and combination index analyses, t- test with 2-sided comparison was used, experiments were in triplicate. Results: RNASeq showed significant heterogeneity in baseline expression of early and late autophagy-related genes among BC cell lines; elevated expression of multiple autophagy-related genes was a prevalent phenomenon. CTSD level was elevated in multiple cell lines. PD analysis showed dose-dependent increase of CTSD expression in UM-UC-3 cells after ROC-325 (1-10uM) treatment correlating with reduced cell viability. The activity of G and C was greater in UM-UC-6 vs UM-UC-3 cells. Both cell lines were sensitive to ROC-325. The addition of ROC-325 to G or C yielded additive benefit in both cell lines. In UM-UC-6, ROC-325 addition significantly increased the activity of GC combination vs GC alone (p = 0.0049). Conclusions: AI merits further investigation as new treatment strategy in BC. Evaluation of in vitro and in vivo efficacy/safety of ROC-325 with/without other agents, and assessment of putative predictive biomarkers is being pursued in BC models with genomic and transcriptomic annotation.

The requirement of GnRH at the beginning of the five-day CO-Synch + controlled internal drug release protocol in beef heifers

The objective of this study was to determine if the omission of GnRH at controlled internal drug release device (CIDR) insertion would impact pregnancy rates to timed AI (TAI) in beef heifers enrolled in a 5-d CO-Synch + CIDR protocol that used 1 PGF2α dose given at CIDR removal. Yearling beef heifers in Ohio in 2 consecutive breeding seasons (2011, n = 151, and 2012, n = 143; Angus × Simmental), Utah (2012, n = 265; Angus × Hereford), Idaho (2012, n = 127; Charolais), and Wyoming (2012, n = 137; Angus) were enrolled in the 5-d CO-Synch + CIDR protocol. At CIDR insertion (d -5), heifers were randomly assigned either to receive 100 μg GnRH (GnRH+; n = 408) or not to receive GnRH (GnRH-; n = 415). At CIDR removal (d 0 of the experiment), 25 mg PGF2α was administered to all heifers. All heifers were inseminated by TAI and given 100 μg GnRH 72 h after PGF2α (d 3). In heifers at the Ohio locations (n = 294), presence of a corpus luteum (CL) at CIDR insertion (d -5) was determined via assessment of progesterone concentrations (2011) and ovarian ultrasonography (2012). Subsequently, in both years, ovarian ultrasound was conducted on d 0 to determine the presence of a new CL. In this same subgroup of heifers, blood samples for progesterone analysis were collected on d 3 to assess luteal regression. Pregnancy diagnosis was performed between 32 and 38 d after TAI. At CIDR withdrawal, presence of a new CL was greater (P < 0.05) in the GnRH+ (55.8%, 82/147) than GnRH- (26.5%, 39/147) treatment. Incidence of failed luteal regression did not differ between the GnRH+ (3.4%) and GnRH- (0.7%) treatments. Pregnancy rate to TAI did not differ between the GnRH+ (50.5%) and GnRH- (54.9%) treatments. In conclusion, although the incidence of a new CL at CIDR removal was increased in the GnRH+ treatment, omission of the initial GnRH treatment in the 5-d CO-Synch + CIDR protocol did not influence TAI pregnancy rate in yearling beef heifers. In addition, a single dose of PGF2α at CIDR removal was effective at inducing luteolysis in yearling beef heifers enrolled in the 5-d CO-Synch + CIDR protocol, regardless of whether or not the initial GnRH treatment was given.

A randomized phase 2 trial of gemcitabine/cisplatin with or without cetuximab in patients with advanced urothelial carcinoma

BACKGROUND

Epidermal growth factor receptor overexpression is associated with poor outcomes in urothelial carcinoma (UC). Cetuximab (CTX) exhibited an antitumor effect in in vivo UC models. The efficacy of gemcitabine/cisplatin (GC) with or without CTX in patients with advanced UC was evaluated.

METHODS

Patients with advanced UC, measurable disease, and adequate organ function were randomized 1:2 to cisplatin (70 mg/m(2) ) on day 1 plus gemcitabine (1000 mg/m(2) ) on days 1, 8, and 15 (arm A) or GC plus CTX (500 mg/m(2) ) on days 1 and 15 (arm B). The primary endpoint was the overall response rate. The secondary endpoints were the response duration, safety, progression-free survival, overall survival, determination of whether or not CTX sensitized nonresponders to GC, and exploratory biomarker analysis. The accrual targets were 27 and 54 patients for the 2 arms, respectively. The overall response rate was reported by arm with binomial confidence intervals (CIs). Kaplan-Meier methods were used for time-to-event endpoints.

RESULTS

Eighty-eight eligible patients were randomized; 87 were toxicity-evaluable, and 85 were response-evaluable. The overall response rates were 57.1% for arm A (95% CI = 37%-76%) and 61.4% for arm B (95% CI = 48%-74%). The median progression-free survival times were 8.5 months for arm A (95% CI = 5.7-10.4 months) and 7.6 months for arm B (95% CI = 6.1-8.7 months). The median overall survival times were 17.4 months for arm A (95% CI = 12.8 months to unreached) and 14.3 months for arm B (95% CI = 11.6-22.2 months). The most common grade 3/grade 4 adverse events in both arms were myelosuppression and nausea. Thromboembolism, acneiform rash, fatigue, pain, hypersensitivity reactions, elevated transaminases, hyponatremia, and hypomagnesemia were more common in arm B; 3 grade 5 adverse events occurred in arm B. The presence of primary disease significantly correlated with thromboembolism. An increased soluble E-cadherin level after cycle 2 correlated with a higher risk of death.

CONCLUSIONS

GC plus CTX was feasible but was associated with more adverse events and no improvements in outcomes.

Triennial Reproduction Symposium: deficiencies in the uterine environment and failure to support embryonic development

Pregnancy failure in livestock can result from failure to fertilize the oocyte or embryonic loss during gestation. The focus of this review is on cattle and factors affecting and mechanisms related to uterine insufficiency for pregnancy. A variety of factors contribute to embryonic loss and it may be exacerbated in certain animals, such as high-producing lactating dairy cows, and in some cattle in which estrous synchronization and timed AI was performed, due to reduced concentrations of reproductive steroids. Recent research in beef cattle induced to ovulate immature follicles and in lactating dairy cows indicates that deficient uterine function is a major factor responsible for infertility in these animals. Failure to provide adequate concentrations of estradiol before ovulation results in prolonged effects on expression and localization of uterine genes and proteins that participate in regulating uterine functions during early gestation. Furthermore, progesterone concentrations during early gestation affect embryonic growth, interferon-tau production, and uterine function. Therefore, an inadequate uterine environment induced by insufficient steroid concentrations before and after ovulation could cause early embryonic death either by failing to provide an adequate uterine environment for recognition of embryo signaling, adhesion, and implantation or by failing to support appropriate embryonic growth, which could lead to decreased conceptus size and failed maternal recognition of pregnancy.

Effect of intrauterine administration of gonadotropin releasing hormone with glycerol on serum LH concentrations in lactating dairy cows

The objectives of the study were to assess: (1) preovulatory serum LH concentrations and (2) synchrony of ovulation after im or iu administration of GnRH with or without the addition of glycerol. Cows were presynchronized with 2 injections of PGF2α given 14d apart (starting at 26±3DIM) followed by Ovsynch (OV; GnRH-7d-PGF2α-48h-GnRH) 12d later. At the time of the second GnRH of OV (GnRH2), cows were blocked by parity and randomly allocated to 1 of 4 treatments: (1) control (CON; n=8) received 2mL of sterile water im; (2) im (IM; n=8) received 100μg of GnRH im; (3) cows were infused with 200μg GnRH into the uterus (IU; n=9); and (4) iu administration of 200μg GnRH plus glycerol 7% v/v (IUG; n=8). Serum circulating progesterone concentrations at hour 0 did not differ (P>0.05) among groups. Concentrations of LH were greater (P<0.05) in IM than IU, IUG, and CON cows at hours 1, 1.5, 2, and 3. All cows ovulated within 48h in the IM (8/8) group followed by IU (6/9) and IUG (4/8) groups, and only two out of eight cows ovulated in the CON group. Although iu administration of GnRH in the IU and IUG groups resulted in lower serum concentrations of LH than IM cows, IU or IUG cows were able to ovulate within 48h after GnRH2 administration.

The E2F1/DNMT1 axis is associated with the development of AR negative castration resistant prostate cancer

BACKGROUND

Research on castration resistant prostate cancer (CRPC) has focused primarily on functional alterations of the androgen receptor (AR). However, little is known about the loss of AR gene expression itself and the possible contribution of AR negative cells to CRPC.

METHODS

Human and murine prostate cancer tissue microarrays (TMAs) were evaluated with antibodies specific for E2F1, DNA methyltransferase 1 or AR. The human prostate cancer TMA consisted of clinical samples ranging from normal tissue to samples of metastatic disease. The murine TMA was comprised of benign, localized or metastatic prostate cancer acquired from TRAMP mice treated with castration and/or 5'-Aza-2'-deoxycytidine (5Aza).

RESULTS

Immunohistochemical analysis revealed increased nuclear DNMT1 staining in localized PCa (P < 0.0001) and metastatic PCa (P < 0.0001) compared to normal tissue. Examination of specific diagnoses revealed that Gleason seven tumors exhibited greater nuclear DNMT1 staining than Gleason six tumors (P < 0.05) and that metastatic tissue exhibited greater levels of nuclear DNMT1 than Gleason seven tumors (P < 0.01). Evaluation of the murine tissue cores revealed that 8.2% and 8.1% of benign tissue cores stained positive for E2F1 and DNMT1 respectively, while 97.0% were AR positive. Conversely, 81% and 100% of tumors were positive for E2F1 and DNMT1 respectively. This was in stark contrast to only 18% of tumors positive for AR. Treatment of mice with 5Aza reduced DNMT1 staining by 30%, while AR increased by 27%.

CONCLUSIONS

These findings demonstrate that the E2F1/DNMT1 inhibitory axis of AR transcription is activated during the emergence of CRPC.

Evaluation of the antitumor activity of dacomitinib in models of human bladder cancer

Members of the human epidermal growth factor receptor (HER) family play a significant role in bladder cancer progression and may underlie the development of chemotherapy resistance. Dacomitinib is an irreversible tyrosine kinase inhibitor with structural specificity for the catalytic domains of epidermal growth factor receptor (EGFR), HER2 and HER4 that has exhibited vigorous efficacy against other solid tumors. We evaluated the antitumor activity of dacomitinib in human bladder cancer cell lines expressing varying levels of HER family receptors. These cell lines also were established as bladder cancer xenografts in nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice to assess dacomitinib activity in vivo. Significant cytotoxic and cytostatic effects were noted in cells expressing elevated levels of the dacomitinib target receptors with apoptosis and cell cycle arrest being the predominant mechanisms of antitumor activity. Cells expressing lower levels of HER receptors were much less sensitive to dacomitinib. Interestingly, dacomitinib was more active than either trastuzumab or cetuximab in vitro, and exhibited increased growth inhibition of bladder tumor xenografts compared with lapatinib. Pharmacodynamic effects of dacomitinib included decreased E-cadherin (E-cad) expression, reduction of EGFR and extracellular signal-regulated kinase (ERK) phosphorylation and reduced mitotic count. Dacomitinib also inhibited tumor growth in a chemotherapy-resistant xenograft and, when combined with chemotherapy in a sensitive xenograft, exhibited superior antitumor effects compared with individual treatments. Evaluation in xenograft-bearing mice revealed that this combination was broadly feasible and well tolerated. In conclusion, dacomitinib exhibited pronounced activity both as a single agent and when combined with chemotherapy in human bladder cancer models. Further investigation of dacomitinib in the preclinical and clinical trial settings is being pursued.

Effect of progesterone concentrations, follicle diameter, timing of artificial insemination, and ovulatory stimulus on pregnancy rate to synchronized artificial insemination in postpubertal Nellore heifers

Two experiments were designed to evaluate the effects of treatments with low versus high serum progesterone (P4) concentrations on factors associated with pregnancy success in postpubertal Nellore heifers submitted to either conventional or fixed timed artificial insemination (FTAI). Heifers were synchronized with a new controlled internal drug release device (CIDR; 1.9 g of P4 [CIDR1]) or a CIDR previously used for 18 days (CIDR3) plus 2 mg of estradiol (E2) benzoate on Day 0 and 12.5 mg of prostaglandin F2α on Day 7. In experiment 1 (n = 723), CIDR were removed on Day 7 or 9 and heifers were inseminated after estrus detection. In experiment 2 (n = 1083), CIDR were all removed on Day 9 and FTAI was performed either 48 hours later in heifers that received E2 cypionate (ECP) on Day 9 (0.5 mg; E48) or 54 or 72 hours later in conjunction with administration of GnRH (100 μg; G54 or G72). Synchronization with CIDR1 resulted in greater serum P4 concentrations and smaller follicle diameters on Days 7 and 9 in both experiments. In experiment 1, treatment with CIDR for 9 days decreased the interval from CIDR removal to estrus (Day 7, 3.76 ± 0.08 days vs. Day 9, 2.90 ± 0.07; P < 0.01) and improved conception (Day 7, 57.1% vs. Day 9, 65.8%; P = 0.05) and pregnancy rates (Day 7, 37.6% vs. Day 9, 45.3%; P = 0.04). In experiment 2, treatment with ECP improved (P < 0.01) the proportion of heifers in estrus (E48, 40.9%(a); G54, 17.1%(c); and G72, 32.0%(b)), but the pregnancy rate was not affected (P = 0.64) by treatments (E48, 38.8%; G54, 35.5%; G72, 37.5%). Synchronization with CIDR3 increased follicle diameter at FTAI (CIDR1, 11.07 ± 0.10 vs. CIDR3, 11.61 ± 0.10 mm; P < 0.01), ovulation rate (CIDR1, 82.8% vs. CIDR3, 88.0%; P < 0.01) and did not affect conception (CIDR1, 42.2 vs. CIDR3, 45.1%; P = 0.38) or pregnancy rates (CIDR1, 34.7 vs. CIDR3, 39.4%; P = 0.11). In conclusion, length of treatment with P4 affected the fertility of heifers bred based on estrus detection. When the heifers were submitted to FTAI protocol, follicle diameter at FTAI (≤10.7 mm, 23.6%; 10.8-15.7 mm, 51.5%; ≥15.8 mm, 30.0%; P < 0.01) was the main factor that affected conception and pregnancy rates.

Investigation of a novel irreversible pan-HER inhibitor combined with chemotherapy in bladder cancer models

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Background: Human Epidermal Receptors (HER) play an important role in bladder cancer (BCa) progression and may mediate chemotherapy resistance. Dacomitinib (Dac) is a novel, potent, irreversible pan-HER inhibitor with activity in several solid tumors, currently in phase III trials in NSCLC. We showed that Dac has single agent anti-tumor activity in human BCa models in vitro and in vivo, inducing apoptosis and G1 arrest. We hypothesized that Dac has additive effects with Gemcitabine (G) and Cisplatin (C) in BCa xenografts. Methods: UM-UC-6 (UC6) or UM-UC-9 (UC9) xenografts were established in age-matched NOD/SCID mice. A week after injection, mice had small tumors, were randomized and treated with i. G 50mg/kg + C 2mg/kg via 3 weekly intra-peritoneal injections (IPI) + daily p.o. buffer for 3 weeks; ii. Dac 6mg/kg p.o. daily for 3 weeks + 3 weekly IPI (saline); iii. GC (same dose/schedule) + Dac starting 1 day after GC (based on cell cycle effect and kinetics); iv. no treatment (control). Mice were monitored daily, weighed weekly, sacrificed at 4 weeks and tumors were weighed. 3 tumors/group were stained for EGFR, HER2, Ki67, E-cadherin, ALDH, p-EGFR, p-ERK, p-Akt. 3rd GC dose in UC6 model was given at 50% due to weight loss; all GC doses were given at 50% in UC9 model. Mann-Whitney test with multiple comparison adjustments was used for analysis. Results: Dac- and GC+Dac-treated mice had no significant weight loss. UC6 tumor weights were significantly lower in Dac and GC+Dac vs control (p<0.0001) or GC (p<0.0001), corresponding to decreased p-ERK %cell expression and staining intensity. GC and control had similar tumor weights (p=0.19). 5 Dac and 3 GC+Dac UC6-injected mice had no tumor at 4 weeks. UC9 tumor weights were significantly lower in Dac (p=0.002, 6x reduction) or GC (p=0.0006; 7x reduction) vs control. GC+Dac had significantly lower tumor weights vs GC (p=0.005), Dac (p=0.06) or control (p<0.0001; 17x reduction). Conclusions: Dac had dramatic singe-agent activity in UC6 xenograft that was GC-resistant. Dac+GC was superior to GC in UC9 xenograft, supporting clinical evaluation. Further investigation of Dac anti-tumor activity and predictive biomarker discovery in additional bladder cancer models is pursued.

HER2 drives luminal breast cancer stem cells in the absence of HER2 amplification: implications for efficacy of adjuvant trastuzumab

Although current breast cancer treatment guidelines limit the use of HER2-blocking agents to tumors with HER2 gene amplification, recent retrospective analyses suggest that a wider group of patients may benefit from this therapy. Using breast cancer cell lines, mouse xenograft models and matched human primary and metastatic tissues, we show that HER2 is selectively expressed in and regulates self-renewal of the cancer stem cell (CSC) population in estrogen receptor-positive (ER(+)), HER2(-) luminal breast cancers. Although trastuzumab had no effects on the growth of established luminal breast cancer mouse xenografts, administration after tumor inoculation blocked subsequent tumor growth. HER2 expression is increased in luminal tumors grown in mouse bone xenografts, as well as in bone metastases from patients with breast cancer as compared with matched primary tumors. Furthermore, this increase in HER2 protein expression was not due to gene amplification but rather was mediated by receptor activator of NF-κB (RANK)-ligand in the bone microenvironment. These studies suggest that the clinical efficacy of adjuvant trastuzumab may relate to the ability of this agent to target the CSC population in a process that does not require HER2 gene amplification. Furthermore, these studies support a CSC model in which maximal clinical benefit is achieved when CSC targeting agents are administered in the adjuvant setting. Cancer Res; 73(5); 1635-46. ©2012 AACR.

Evaluation of a novel irreversible pan-HER inhibitor in bladder cancer models

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Background: Human epidermal receptors (HER) are overexpressed and HER signaling is biologically relevant in bladder cancer and may mediate chemotherapy resistance. Dacomitinib is a novel, potent, irreversible pan-HER inhibitor with activity against several solid tumors, currently in a phase III clinical trial in NSCLC. We hypothesized that dacomitinib has antitumor activity in bladder cancer models. Methods: Expression level of EGFR and HER2 protein was measured semi-quantitatively in 8 bladder cancer cell lines. We treated UM-UC-3, UM-UC-6, UM-UC-9 cell lines with dacomitinib (1nM-10uM) for 24-72 hours, and measured cell viability, proliferation, apoptosis, and cell cycle effects. Correlations between dose and cell viability were measured by two-way ANOVA (GraphPad Prism 5.0). We injected age-matched male NOD/SCID mice SC with 1x106 UM-UC-6 and UM-UC-9 cells, respectively, generating xenografts. Mice were randomized and treated with dacomitinib, 6mg/kg p.o. daily, starting 1 day or 1 week after cell injection; controls were treated with vehicle. Mice were monitored daily, weighed weekly, sacrificed at 4 weeks and tumors weighed. Results: In vitro, significant cytostatic effect was noted with as low as 50nM in UM-UC6 cells and 100nM in UM-UC9 cells. UM-UC3 cells did not exhibit cytostatic effect even with 1000nM, corresponding to differential target protein (HER) expression. Dacomitinib (2uM) induced apoptosis (UM-UC-6), and G1 cell cycle arrest in both cell lines. These effects corresponded to dacomitinib-mediated inhibition of EGFR, ERK, AKT phosphorylation. In vivo, xenograft weights in both cell lines were significantly lower in dacomitinib-treated mice vs control (p<0.001), corresponding to pharmacodynamic effects (decreased E-cadherin, p-EGFR, p-ERK, mitotic count). Dacomitinib 6mg/kg p.o. daily resulted in significantly lower tumor weights vs lapatinib 50 mg/kg p.o. daily in UM-UC-9 xenograft model (p=0.0052). Conclusions: Dacomitinib demonstrated single-agent activity in bladder cancer cell lines and xenografts. Induction of apoptosis and G1 phase arrest are the suggested mechanisms for anti-tumor activity. Further investigation of this inhibitor in bladder cancer models is being pursued.

Triennial Reproduction Symposium: the obstacle course to successful establishment of pregnancy in domestic livestock species

The 2012 Triennial Reproduction Symposium (TRS), "Impediments to Fertility in Domestic Animals," was held immediately before the Joint Annual Meeting of the American Society of Animal Science, American Dairy Science Association, Canadian Society of Animal Science, Western Section of the American Society of Animal Science, and the Asociación Mexicana de Producción Animal in Phoenix, AZ, in July, 2012. The theme of the symposium highlighted key impediments or opportunities in the process of creating a pregnancy, beginning with male and female gametes and ending with a viable fetus. The 2012 TRS was designed to focus on areas of current and exciting investigation across a variety of species and to include 8 presentations from a mix of established and early-career scientists. The TRS was also the venue for presentation of the 2012 L. E. Casida Award for Graduate Education; the recipient was R. D. Randel (Texas A&M University). The symposium provided an excellent opportunity for reproductive biologists to consider the broad spectrum of factors that limit fertility in domestic species and contemplate the current status of knowledge relative to several of the significant obstacles to pregnancy.

Changing expression of chloride channels during preimplantation mouse development

Plasma membrane chloride channels (ClCs) play important roles in a broad range of cellular processes including cell volume regulation, proliferation, and transepithelial transport, all of which are critical during preimplantation embryonic development. In this study, the molecular and functional expression of voltage-gated ClCs was analyzed throughout preimplantation development of the mouse conceptus. mRNA transcripts for allClcngenes were detected. OnlyClcn1mRNA showed differential expression in the blastocyst, being detected in the trophectoderm but not in the inner cell mass. CLCN3 protein was detected at low levels in the cytoplasm and plasma membrane in 4-cell embryos and was localized to the apical plasma membrane of the trophoblasts in the blastocyst. Whole-cell patch-clamp recordings demonstrated the presence of a DIDS-sensitive, outwardly rectifying Cl−current throughout development, with this conductance being large at the 1-cell, morula and blastocyst stages. A second DIDS-insensitive Cl−current, which was inactivated by membrane depolarization, was present in cells differentiating into the trophoblast lineage and during blastocyst expansion. Inhibition of the DIDS-sensitive current and the DIDS-insensitive current, with 9-AC, prevented blastocyst expansion.

Randomized phase II trial of gemcitabine/cisplatin (GC) with or without cetuximab (CET) in patients (pts) with advanced urothelial carcinoma (UC)

4506

Background: In UCpts EGFR over-expression correlates with high grade, stage, progression, short survival. Preclinical data show enhanced anti-tumor effect with CET + chemotherapy (CT). In several solid tumors CET added to CT improved survival. CET is hypothesized to improve UC response to CT. Methods: Pts with ECOG PS 0-2, adequate organ function, unresectable, locally recurrent or metastatic UC were stratified by disease state and randomized (1:2) to C 70mg/m2 d1, G 1000mg/m2 d1, d8, d15 (Arm A) or same CT + CET 500mg/m2 d1, d15 (Arm B) q28 days. Due to high thromboembolic events rate in Arm B, G dose was reduced to 800 mg/m2. 6 GC cycles were planned. Arm A pts progressing after 2 GC cycles had CET added. Arm B pts were to continue on CET monotherapy after 4-6 CT cycles. Imaging was q8 weeks. Primary endpoint: RECIST response rate (RR); secondary: safety, PFS, survival. Since E-cadherin impacts UC response to CET in vitro, serum level (sE-cad) was assessed at baseline, after 2 cycles, end of CT and at progression. With 1-stage design, assuming RR 50% (Arm A) and at least 65% (Arm B), planned sample size was 27/54 pts. RR improvement of 5% has 81% probability if true difference is 15%. Results: 88 pts were eligible and randomized, Arm A/B: median age 66/61 years; bladder primary 71.4%/77.2%; metastatic disease 92.9%/89.5%, median CT cycles number 6/5. 28 Arm B pts continued CET (median 3 cycles, range 1-29); 1 Arm A pt had CET added. Most common G3/4 adverse events (AEs) (Arm A, B): neutropenia (34.5%, 33.9%), anemia (10.3%, 5.1%), thrombocytopenia (27.6%, 22%), thromboembolism (6.9%, 18.6%), hyponatremia (3.5%, 10.2%); Arm B only: rash 28.8%, fatigue 11.9%, hypomagnesemia 11.9% and 2 deaths. 84 pts were response evaluable (see table below). sE-cad did not correlate with outcome. sE-cad increased in Arm A, but decreased in Arm B over time. Conclusions: GC/CET was feasible with no outcome improvement but higher AEs. sE-cad did not correlate with outcome. Decreased sE-cad in Arm B suggests potential EGFR-mediated E-cad proteolysis. [Table: see text]

Expression of MET and HGF in bladder cancer tumorigenesis and invasion

4573

Background: The human MET gene encodes the hepatocyte growth factor (HGF) tyrosine kinase receptor. Limited studies in human bladder cancer have demonstrated that expression of MET protein is linked with disease progression and survival. We hypothesized that the expression of both MET and its ligand HGF are altered in bladder cancer. Methods: Expression of MET and HGF in human bladder tissues was explored using Oncomine, an online compendium of cancer transcriptome profiles. The largest relevant dataset was identified and contained 157 samples (Sanchez-Carbayo, et al. 2006). Normalized and log2 transformed mRNA expression values for Affymetrix U133 microarray probe sets corresponding to the genes of interest were compiled and averaged for each gene. Mann-Whitney U testing was used to compare means. Nominal and standard least squares logistic regression was used to evaluate the predictive significance of, and relevance of clinicopathologic variables on, gene expression. Statistical analyses were carried out using JMP 9.0.2. Results: Expression of MET and HGF was compared across subsets of normal bladder tissue (n=48), superficial tumors (n=28), and invasive tumors (n = 81). Relative to normal tissue, MET expression was greater in superficial (p = 0.0008) and invasive tumors (p<0.0001). HGF expression was reduced in both invasive and superficial tumors vs. normal tissue (both p< 0.0001), but was higher in invasive vs. superficial tumors (p= 0.0007). In a logistic regression model of tumor samples, both MET and HGF correlated with tumor invasion (model p=0.0003). Interaction between MET and HGF was not significant (p=0.55). Neither MET nor HGF expression was predicted by regression using age, gender, grade, or nodal stage (p=0.16 and 0.27, respectively). Conclusions: Decreased HGF expression and MET over-expression are strongly associated with tumorigenesis and invasion in bladder cancer. The reduction in HGF expression is blunted in invasive vs. superficial tumors, suggesting a potential loss of negative feedback in more aggressive tumors. Expression of both genes could not be predicted by modeling clinicopathologic variables. MET signaling represents a potential therapeutic target in bladder cancer.

EGF promotes the shedding of soluble E-cadherin in an ADAM10-dependent manner in prostate epithelial cells

During the progression of prostate cancer, the epithelial adhesion molecule E-cadherin is cleaved from the cell surface by ADAM15 proteolytic processing, generating an extracellular 80kDa fragment referred to as soluble E-cadherin (sE-cad). Contrary to observations in cancer, the generation of sE-cad appears to correlate with ADAM10 activity in benign prostatic epithelium. The ADAM10-specific inhibitor INCB8765 and the ADAM10 prodomain inhibit the generation of sE-cad, as well as downstream signaling and cell proliferation. Addition of EGF or amphiregulin (AREG) to these untransformed cell lines increases the amount of sE-cad shed into the conditioned media, as well as sE-cad bound to EGFR. EGF-associated shedding appears to be mediated by ADAM10 as shRNA knockdown of ADAM10 results in reduced shedding of sE-cad. To examine the physiologic role of sE-cad on benign prostatic epithelium, we treated BPH-1 and large T immortalized prostate epithelial cells (PrEC) with an sE-cad chimera comprised of the human Fc domain of IgG(1), fused to the extracellular domains of E-cadherin (Fc-Ecad). The treatment of untransformed prostate epithelial cells with Fc-Ecad resulted in phosphorylation of EGFR and downstream signaling through ERK and increased cell proliferation. Pre-treating BPH-1 and PrEC cells with cetuximab, a therapeutic monoclonal antibody against EGFR, decreased the ability of Fc-Ecad to induce EGFR phosphorylation, downstream signaling, and proliferation. These data suggest that ADAM10-generated sE-cad may have a role in EGFR signaling independent of traditional EGFR ligands.

Prepartum dietary energy source fed to beef cows: I. Effects on pre- and postpartum cow performance

Mature Angus-cross beef cows (n = 144) were used to determine effects of late gestation dietary energy source on pre- and postpartum cow performance in a complete randomized block design experiment. Cows were adapted to diets starting at 167 +/- 9 d of gestation and fed until 1 wk before expected calving date. Cows were fed 1 of 3 dietary energy sources: grass hay (HY), corn (CN), or dried distillers grains (DDGS). Cows allotted to HY were allowed ad libitum access to round-bale grass hay, and average hay disappearance was 12.4 kg/d. Limit-fed corn and DDGS diets contained 5.3 kg of whole-shelled corn or 4.1 kg of DDGS, respectively, plus 2.1 kg of hay, and 1.0 kg of supplement to meet cow nutritional needs during late gestation and to allow for an energy intake similar to HY. Every 21 d, BW, BCS, and ultrasound measurement of backfat between the 12th and 13th ribs were collected. At 210 d in gestation, jugular blood samples were collected from cows at 0, 3, 6, and 9 h postfeeding and were analyzed for glucose, insulin, NEFA, and blood urea N (BUN) concentrations. After parturition, cows were fed a common diet and managed similarly. Milk production was determined by weigh-suckle-weigh procedure on d 31, 100, and 176 postpartum. Cows fed DDGS during late gestation gained more (P = 0.04) BW than cows fed HY or CN; however, no difference in BCS change was detected (P = 0.28) among treatments. Plasma glucose concentrations were similar among treatments (P = 0.64), whereas insulin concentrations at 3 h postfeeding were greater (P = 0.002) for cows fed DDGS than those fed HY or CN. Plasma BUN concentrations were greater (P < or = 0.02) for cows fed DDGS vs. CN or HY up to 6 h postfeeding. Birth weight was greater (P < 0.001) for calves from cows fed CN and DDGS than for those fed HY, but this did not result in any differences in frequency of dystocia (P = 0.21). Prepartum energy source did not affect conception rates (P = 0.79), milk production (P > or = 0.51), or milk composition (P > or = 0.39). Maternal dietary energy source in late gestation did not affect pre- or postpartum cow performance, but did change plasma hormones and metabolites during gestation. Heavier birth weights in calves from cows fed CN or DDGS indicate the changes in maternal metabolism affected energy partitioning of nutrients to the fetus and subsequent fetal growth.

ADAM15 regulates endothelial permeability and neutrophil migration via Src/ERK1/2 signalling

AIMS

Endothelial barrier dysfunction is a key event in the pathogenesis of vascular diseases associated with inflammation. ADAM (a disintegrin and metalloprotease) 15 has been shown to contribute to the development of vascular inflammation. However, its role in regulating endothelial barrier function is unknown. The aim of this study was to examine the effect of ADAM15 on endothelial permeability and its underlying mechanisms.

METHODS AND RESULTS

By measuring albumin transendothelial flux and transendothelial electric resistance in cultured human umbilical vein endothelial cell monolayers, we found that depletion of ADAM15 expression via siRNA decreased endothelial permeability and attenuated thrombin-induced barrier dysfunction. In contrast, endothelial cells overexpressing either wild-type or catalytically dead mutant ADAM15 displayed a higher basal permeability and augmented hyperpermeability in response to thrombin. In addition, ADAM15 knockdown inhibited whereas ADAM15 overexpression promoted neutrophil transendothelial migration. Further molecular assays revealed that ADAM15 did not cleave vascular endothelial-cadherin or cause its degradation. However, overexpression of ADAM15 promoted extracellular signal-regulated kinase (ERK)1/2 phosphorylation in both non-stimulated and thrombin-stimulated endothelial cells in a protease activity-independent manner. Pharmacological inhibition of Src kinase or ERK activation reversed ADAM15-induced hyperpermeability and neutrophil transmigration.

CONCLUSION

The data provide evidence for a novel function of ADAM15 in regulating endothelial barrier properties. The mechanisms of ADAM15-induced hyperpermeability involve Src/ERK1/2 signalling independent of junction molecule shedding.

The therapeutic potential of ADAM15

ADAM15 is a widely expressed multi-domain protease that has been implicated in the pathogenesis of many human diseases. Given the diversity of the ADAM15 functional domains, this protease is thought to affect several important cellular processes, including cell adhesion, degradation of extracellular matrix components, and ectodomain shedding of membrane-bound growth factors that are intrinsic to cancer and various inflammatory conditions. The multiple levels by which the activity of ADAM15 can be regulated include signal transduction, modulation of catalytic function, spatial regulation, and post-translational modifications. Taken together, this multi-functional disintegrin protease not only offers a variety of potential targets for therapeutic intervention, but also represents an attractive target for pharmaceutical consideration due to its involvement in key cellular processes and various disease states. Modalities aimed at inhibiting protease activation, metalloproteinase activity, or integrin binding capability could prove beneficial for the treatment of cancer and inflammatory diseases.

Five years of conserving the ‘world's rarest snake’, the Antiguan racer Alsophis antiguae

Abstract The Critically Endangered Antiguan racer Alsophis antiguae is confined to Great Bird Island, a 9.9 ha (24.5-acre) islet off the north-east coast of Antigua in the Lesser Antilles. This island represents well under 0.1 per cent of the species's historical distribution range. During the past 5 years, the total number of racers aged 1 year or more has fluctuated between 51 and 114, and currently stands at approximately 80. Since 1995, the Antiguan Racer Conservation Project (ARCP) has en-deavoured to save this harmless snake from extinction by using a combination of education, conservation breeding, habitat restoration, local capacity building and applied research. The Antiguan racer's ecology and population dynamics have become well understood after 5 years of intensive study, and the species has evidently benefited from the project's rat eradication programme. The snakes are still seriously threatened by other intrinsic and extrinsic factors, however, including inbreeding depression, frequent hurricanes, invasive predators and deliberate killing by tourists, as well as the problem that Great Bird Island is too small to support more than about 100 individuals. This paper describes the activities and impact of this project to date, and outlines a series of conservation activities to safeguard the long-term future of the species, which include reintroduction of the Antiguan racer to restored islands within its former distribution range.

RANKL inhibition is an effective adjuvant for docetaxel in a prostate cancer bone metastases model

BACKGROUND

Docetaxel induces an anti-tumor response in men with advanced prostate cancer (PCa); however, the side effects associated with docetaxel treatment can be severe, resulting in discontinuation of therapy. Thus, identification of an effective adjuvant therapy to allow lower doses of docetaxel is needed. Advanced PCa is typically accompanied by skeletal metastasis. Receptor activator of NFkB ligand (RANKL) is a key pro-osteoclastic factor. Targeting RANKL decreases establishment and progression of PCa growth in bone in murine models.

METHODS

The efficacy of inhibiting RANKL, using a recombinant soluble RANK extracellular domain fused with the immunoglobulin Fc domain (RANK-Fc), was tested as an adjuvant therapy with docetaxel for PCa bone metastasis in a murine intra-tibial model.

RESULT

The combination of RANK-Fc and docetaxel reduced tumor burden in bone greater than either treatment alone.

CONCLUSION

The combination of docetaxel with a RANKL-inhibiting agent merits further investigation for treatment of advance PCa.

The ectodomain shedding of E-cadherin by ADAM15 supports ErbB receptor activation

The zinc-dependent disintegrin metalloproteinases (a disintegrin and metalloproteinases (ADAMs) have been implicated in several disease processes, including human cancer. Previously, we demonstrated that the expression of a catalytically active member of the ADAM family, ADAM15, is associated with the progression of prostate and breast cancer. The accumulation of the soluble ectodomain of E-cadherin in human serum has also been associated with the progression of prostate and breast cancer and is thought to be mediated by metalloproteinase shedding. Utilizing two complementary models, overexpression and stable short hairpin RNA-mediated knockdown of ADAM15 in breast cancer cells, we demonstrated that ADAM15 cleaves E-cadherin in response to growth factor deprivation. We also demonstrated that the extracellular shedding of E-cadherin was abrogated by a metalloproteinase inhibitor and through the introduction of a catalytically inactive mutation in ADAM15. We have made the novel observation that this soluble E-cadherin fragment was found in complex with the HER2 and HER3 receptors in breast cancer cells. These interactions appeared to stabilize HER2 heterodimerization with HER3 and induced receptor activation and signaling through the Erk pathway, supporting both cell migration and proliferation. In this study, we provide evidence that ADAM15 catalyzes the cleavage of E-cadherin to generate a soluble fragment that in turn binds to and stimulates ErbB receptor signaling.

The role of Nrf2 in increased reactive oxygen species and DNA damage in prostate tumorigenesis

The impact of oxidative stress in human cancer has been extensively studied. It is accepted that elevated reactive oxygen species (ROS) promote mutagenic DNA damage. Even with an extensive armament of cellular antioxidants and detoxification enzymes, alterations to DNA occur that initiate cellular transformation. Erythroid 2p45 (NF-E2)-related factor 2 (Nrf2) is a basic-region leucine zipper transcription factor that mediates the expression of key protective enzymes through the antioxidant-response element (ARE). By analysing 10 human prostate cancer microarray data sets, we have determined that Nrf2 and members of the glutathione-S-transferase (GST) mu family are extensively decreased in human prostate cancer. Using the TRAMP transgene and Rb and Nrf2 knockout murine models, we demonstrated that the loss of Nrf2 initiates a detrimental cascade of reduced GST expression, elevated ROS levels and ultimately DNA damage associated with tumorigenesis. Based on overwhelming data from clinical samples and the current functional analysis, we propose that the disruption of the Nrf2-antioxidant axis leads to increased oxidative stress and DNA damage in the initiation of cellular transformation in the prostate gland.

ADAM15 supports prostate cancer metastasis by modulating tumor cell-endothelial cell interaction

Using human tumor and cDNA microarray technology, we have recently shown that the ADAM15 disintegrin is significantly overexpressed during the metastatic progression of human prostate cancer. In the current study, we used lentiviral-based short hairpin RNA (shRNA) technology to down-regulate ADAM15 in the metastatic prostate cancer cell line, PC-3. ADAM15 down-regulation dramatically attenuated many of the malignant characteristics of PC-3 cells in vitro and prevented the s.c. growth of PC-3 cells in severe combined immunodeficient (SCID) mice. By inhibiting the expression of ADAM15 in PC-3 cells, we showed decreased cell migration and adhesion to specific extracellular matrix proteins. This was accompanied by a reduction in the cleavage of N-cadherin by ADAM15 at the cell surface. Fluorescence-activated cell sorting analysis revealed reduced cell surface expression of the metastasis-associated proteins alpha(v) integrin and CD44. Furthermore, matrix metalloproteinase 9 secretion and activity were abrogated in response to ADAM15 reduction. In an in vitro model of vascular invasion, loss of ADAM15 reduced PC-3 adhesion to, and migration through, vascular endothelial cell monolayers. Using an SCID mouse model of human prostate cancer metastasis, we found that the loss of ADAM15 significantly attenuated the metastatic spread of PC-3 cells to bone. Taken together, these data strongly support a functional role for ADAM15 in prostate tumor cell interaction with vascular endothelium and the metastatic progression of human prostate cancer.

Synchronization of estrus in suckled beef cows for detected estrus and artificial insemination and timed artificial insemination using gonadotropin-releasing hormone, prostaglandin F2alpha, and progesterone

We determined whether a fixed-time AI (TAI) protocol could yield pregnancy rates similar to a protocol requiring detection of estrus, or estrous detection plus TAI, and whether adding a controlled internal device release (CIDR) to GnRH-based protocols would enhance fertility. Estrus was synchronized in 2,598 suckled beef cows at 14 locations, and AI was preceded by 1 of 5 treatments: 1) a CIDR for 7 d with 25 mg of PG F(2alpha) (PGF) at CIDR removal, followed by detection of estrus and AI during the 84 h after PGF; cows not detected in estrus by 84 h received 100 mug of GnRH and TAI at 84 h (control; n = 506); 2) GnRH administration, followed in 7 d with PGF, followed in 60 h by a second injection of GnRH and TAI (CO-Synch; n = 548); 3) CO-Synch plus a CIDR during the 7 d between the first injection of GnRH and PGF (CO-Synch + CIDR; n = 539); 4) GnRH administration, followed in 7 d with PGF, followed by detection of estrus and AI during the 84 h after PGF; cows not detected in estrus by 84 h received GnRH and TAI at 84 h (Select Synch & TAI; n = 507); and 5) Select Synch & TAI plus a CIDR during the 7 d between the first injection of GnRH and PGF (Select Synch + CIDR & TAI; n = 498). Blood samples were collected (d -17 and -7, relative to PGF) to determine estrous cycle status. For the control, Select Synch & TAI, and Select Synch + CIDR & TAI treatments, a minimum of twice daily observations for estrus began on d 0 and continued for at least 72 h. Inseminations were performed using the AM/PM rule. Pregnancy was diagnosed by transrectal ultrasonography. Percentage of cows cycling at the initiation of treatments was 66%. Pregnancy rates (proportion of cows pregnant to AI of all cows synchronized during the synchronization period) among locations across treatments ranged from 37% to 67%. Pregnancy rates were greater (P < 0.05) for the Select Synch + CIDR & TAI (58%), CO-Synch + CIDR (54%), Select Synch & TAI (53%), or control (53%) treatments than the CO-Synch (44%) treatment. Among the 3 protocols in which estrus was detected, conception rates (proportion of cows that became pregnant to AI of those exhibiting estrus during the synchronization period) were greater (P < 0.05) for Select Synch & TAI (70%; 217 of 309) and Select Synch + CIDR & TAI (67%; 230 of 345) cows than for control cows (61%; 197 of 325). We conclude that the CO-Synch + CIDR protocol yielded similar pregnancy rates to estrous detection protocols and is a reliable TAI protocol that eliminates detection of estrus when inseminating beef cows.

CXCL12 Activates a Robust Transcriptional Response in Human Prostate Epithelial Cells

CXCL12 is a CXC-type chemokine that plays important roles in hematopoiesis, development, and organization of the immune system and supports the survival or growth of a variety of normal or malignant cell types. Our laboratory recently showed that CXCL12 is secreted by aging stromal fibroblast cells and is a major paracrine factor that specifically stimulates the proliferation of prostate epithelial cells. The current study shows that this CXCL12-mediated proliferative response may be either ERK-dependent or ERK-independent. Moreover, CXCL12 initiates a previously undefined and complex global transcriptional response in prostate epithelial cells. This CXCL12-mediated transcriptional response directly stimulates the expression of genes encoding proteins that are involved in the promotion of cellular proliferation and progression through the cell cycle, tumor metastasis, and cellular motility, and directly represses the transcription of genes encoding proteins involved in cell-cell adhesion and resistance to apoptosis. Thus, CXCL12 may play a major role in the etiology of benign proliferative disease in the context of an aging tissue microenvironment.

5-aza-2'-deoxycytidine delays androgen-independent disease and improves survival in the transgenic adenocarcinoma of the mouse prostate mouse model of prostate cancer

PURPOSE

We have previously shown that 5-aza-2'-deoxycytidine (5-aza) is an effective chemopreventive agent capable of preventing early disease progression in the transgenic adenocarcinoma of the mouse prostate (TRAMP) model. The purpose of this study was to determine the effect of 5-aza on preexisting TRAMP prostate cancers and prevention of androgen-independent prostate cancer.

EXPERIMENTAL DESIGN

TRAMP mice with established prostate cancers were treated with 5-aza, castration, castration + 5-aza, or vehicle control (PBS). One cohort of 22 mice per treatment was euthanized after 10 weeks of treatment, whereas a second cohort of 14 mice per group was followed until death to determine survival. Histologic sections of prostate, pelvic lymph nodes, lung, and liver were blinded and analyzed by a certified genitourinary pathologist (K.J.W.).

RESULTS

Combined treatment (castration + 5-aza) provided significant survival benefits over either single treatment (combined versus castration P = 0.029, combined versus 5-aza P = 0.036). At 24 weeks of age, 86% of mice within the PBS cohort exhibited histologic evidence of prostate cancer, whereas only 47% of the combined cohort exhibited malignant disease (P < 0.0001). Additionally, whereas 43% of the PBS treatment group exhibited lymph node metastases, these were only observed in 21% of the combined treatment mice.

CONCLUSIONS

This is the first study to examine the effect of 5-aza and combined castration + 5-aza on preexisting prostate cancer in an animal model. Based on these preclinical findings, we suggest that 5-aza treatment may prolong the time to an androgen-independent status and thus survival in a hormone-deprived setting in prostate cancer.

Steroidogenic changes and steady state amount of messenger RNA encoding steroidogenic enzymes, gonadotropin receptors and cell-death signalling in the dominant ovarian follicle during estradiol-induced atresia in cattle

Changes in steroidogenic function and associated gene expression were characterized in dominant ovarian follicles (DF) of cattle where follicles were induced to become atretic by systemic administration of estradiol benzoate (EB). In experiment 1, follicular fluid (FF) steroid concentrations in the DF were measured at 12-hourly time points for 48 h in heifers treated with 1 mg EB i.m./500 kg body weight (EB; n=20) as compared with untreated controls (C; n=19). Treatment with EB promoted a transient reduction in circulating FSH, a rapid (12 h) and sustained reduction in FF estradiol, a rapid (12 h) but transient reduction in FF progesterone and a delayed (36 h) increase in FF testosterone concentrations. In experiment 2, whole follicular wall tissue was collected from DF of mature non-lactating cows allocated to a 0 h control group (0 HC: n=7), a 24h control group (24 HC; n=7) or an EB-treated group where tissue was collected 24 h after administration of 1 mg EB i.m./500 kg body weight (EB; n=8). As for experiment 1, EB promoted a transient reduction in circulating FSH, a pronounced reduction in FF estradiol and a smaller but significant reduction in FF progesterone concentrations. Semi-quantitative RT-PCR on follicular wall tissue revealed that the loss in estrogen activity at 24 h after EB was associated with two-fold reduction in aromatase mRNA, with an apparent acceleration in loss of 17alpha-hydroxylase mRNA. Expression of genes for gonadotropin receptors (LHR and FSHR) and a cell-death signalling pathway (Fas antigen and Fas ligand) were unchanged during the initial 24h of EB-induced atresia. These results suggest that EB initiates atresia in dominant ovarian follicles through a rapid suppression of follicular estradiol synthesis, an effect associated with down-regulation of the aromatase gene. A transient suppression in circulating FSH following administration of EB appears to have initiated these events, and it is suggested that subsequent processes involved in atresia follow this loss in estrogenic function.

Elevated E2F1 inhibits transcription of the androgen receptor in metastatic hormone-resistant prostate cancer

Activation of E2F transcription factors, through disruption of the retinoblastoma (Rb) tumor-suppressor gene, is a key event in the development of many human cancers. Previously, we showed that homozygous deletion of Rb in a prostate tissue recombination model exhibits increased E2F activity, activation of E2F-target genes, and increased susceptibility to hormonal carcinogenesis. In this study, we examined the expression of E2F1 in 667 prostate tissue cores and compared it with the expression of the androgen receptor (AR), a marker of prostate epithelial differentiation, using tissue microarray analysis. We show that E2F1 expression is low in benign and localized prostate cancer, modestly elevated in metastatic lymph nodes from hormone-naïve patients, and significantly elevated in metastatic tissues from hormone-resistant prostate cancer patients (P = 0.0006). In contrast, strong AR expression was detected in benign prostate (83%), localized prostate cancer (100%), and lymph node metastasis (80%), but decreased to 40% in metastatic hormone-resistant prostate cancer (P = 0.004). Semiquantitative reverse transcription-PCR analysis showed elevated E2F1 mRNA levels and increased levels of the E2F-target genes dihyrofolate reductase and proliferating cell nuclear antigen in metastatic hormone-independent prostate cancer cases compared with benign tissues. To identify a role of E2F1 in hormone-independent prostate cancer, we examined whether E2F1 can regulate AR expression. We show that exogenous expression of E2F1 significantly inhibited AR mRNA and AR protein levels in prostate epithelial cells. E2F1 also inhibited an AR promoter-luciferase construct that was dependent on the transactivation domain of E2F1. Furthermore, using chromatin immunoprecipitation assays, we show that E2F1 and the pocket protein family members p107 and p130 bind to the AR promoter in vivo. Taken together, these results show that elevated E2F1, through its ability to repress AR transcription, may contribute to the progression of hormone-independent prostate cancer.

Effect of timing of feeding a high-concentrate diet on growth and attainment of puberty in early-weaned heifers

Precocious puberty (<300 d of age) can be successfully induced in a majority of heifers with early weaning and continuous feeding of a high-concentrate diet. The objective of this experiment was to determine the relative effects of timing of feeding a high-concentrate diet on age at puberty in early-weaned heifers. Sixty crossbred Angus and Simmental heifer calves were weaned at 112 +/- 2 d of age and 155 +/- 3 kg of BW and were fed a receiving diet for 2 wk. Heifers were blocked by age and BW, and assigned randomly to receive a high-concentrate (60% corn; H) or control (30% corn; C) diet during phase 1 (mean age 126 to 196 d) and H or C during phase 2 (mean age 196 to 402 d), resulting in 4 treatments (HH, n = 15; HC, n = 15; CH, n = 15; and CC, n = 15). Blood samples were collected weekly beginning at a mean age of 175 d and assayed for progesterone concentration to determine age at puberty. After 56 d on the experimental diets, BW of heifers fed the H diet during phase 1 were greater (P < 0.05) than those of heifers fed the C diet (mean age of 182 d; treatment x mean age, P < 0.01). After 70 d on the new diets (mean age of 266 d), heifers fed the H diet during phase 2 reached heavier BW (P < 0.05) than heifers fed the C diet, when compared within phase 1 diet groups (HH > HC; CH > CC). Body weights in HC and CH treatments differed from a mean age of 169 through 238 d, after which BW did not differ between these treatments. The ADG over the entire experimental period was greatest for the HH treatment (1.2 +/- 0.04 kg/d; P < 0.05), followed by the HC and CH treatments (1.0 +/- 0.03 and 1.0 +/- 0.02 kg/d, respectively), which were not different, and the CC treatment gained the least (0.7 +/- 0.04 kg/d; P < 0.05). Precocious puberty occurred in 67, 47, 47, and 20% of heifers in the HH, HC, CH, and CC treatments, respectively (HH > CC; P < 0.05). Mean age at puberty for the HH and HC treatments (271 +/- 17 and 283 +/- 17 d of age, respectively) was earlier (P < 0.05) than for the CC treatment (331 +/- 11 d of age). Age at puberty in the CH treatment (304 +/- 13 d of age) was intermediate to and not different from the other treatments. Heifers fed the H diet during phase 1 attained puberty earlier (P < 0.05) than heifers fed the C diet during phase 1. In conclusion, increasing dietary energy intake in early-weaned heifers, through feeding a high-concentrate diet from 126 to 196 d of age, decreased age at puberty regardless of the diet fed after 196 d of age.