A Urine Based Genomic Assay to Triage Patients with Hematuria for Cystoscopy.

PURPOSE: Current clinical guidelines recommend cystoscopy in patients who present with hematuria to rule out a bladder tumor. We evaluated whether our previously developed urine assay was able to triage patients with hematuria for cystoscopy in a large prospective cohort. MATERIALS AND METHODS: A urine sample was collected before cystoscopy and mutation/methylation status of 6 genes was determined on cellular DNA. The existing diagnostic model was validated on this cohort. Logistic regression was applied to investigate other potential variables. The primary end point was the model performance as indicated by the AUC. Secondary end points were sensitivity, specificity and negative predictive value. Clinical usefulness was determined by the net benefit approach. RESULTS: In 838 patients biomarker status could be determined for all genes. Urothelial cancer was observed in 112 patients (98 of 457 in the gross and 14 of 381 in the microscopic hematuria group). Validation of the existing model resulted in an AUC of 0.93. Logistic regression analysis identified type of hematuria as a significant additional variable. Adding type of hematuria resulted in an AUC of 0.95 (96% sensitivity, 73% specificity, 99% negative predictive value). The assay identified all upper tract tumors not visible by cystoscopy (in 6). Net benefit analysis showed that the urine assay should be preferred over current clinical practice. Implementing the urine assay as a triage tool could lead to a 53% reduction in cystoscopies. CONCLUSIONS: The urine assay detected urothelial cancer with a very high accuracy and can be used to triage patients presenting with hematuria for cystoscopy.

Tumor heterogeneity, aggressiveness, and immune cell composition in a novel syngeneic PSA-targeted Pten knockout mouse prostate cancer (MuCaP) model.

BACKGROUND: Prostate cancer is recognized as a heterogeneous disease demanding appropriate preclinical models that reflect tumor complexity. Previously, we established the PSA-Cre;PtenLoxP/LoxP genetic engineered mouse model (GEMM) for prostate cancer reflecting the various stages of tumor development. Prostate tumors in this Pten KO model slowly develop, requiring more than 10 months. In order to enhance its practical utility, we established a syngeneic panel of cell lines derived from PSA-Cre targeted Pten KO tumors, designated the mouse prostate cancer (MuCap) model. METHODS: Four different MuCaP epithelial cell lines were established from three independent primary Pten KO mouse prostate tumors. Tumorigenic capacity of the MuCaP cell lines was determined by subcutaneous inoculation of these cell lines in immunocompetent mice. Response to PI3K-targeted therapy was validated in ex vivo tissue slices of the established MuCaP tumors. RESULTS: The MuCaP cell lines were all tumorigenic in immunocompetent mice after subcutaneous inoculation. Interestingly, these syngrafted tumors represented different tumor growth rates and morphologies. Treatment with the specific PI3K inhibitor GDC0941 resulted in responses very similar between syngeneic MuCaP and primary Pten KO prostate tumors. Finally, immunoprofiling of the different syngeneic MuCaP tumors demonstrated differential numbers of tumor infiltrating lymphocytes and distinct immune gene profiles with expression of CD8, INFy, and PD1 being inversely related to tumor aggressiveness. CONCLUSIONS: Collectively, we present here a well-defined MuCaP platform of in vitro and in vivo mouse prostate cancer models that may support preclinical assessment of (immune)-therapies for prostate cancer.

Validation of a DNA Methylation-Mutation Urine Assay to Select Patients with Hematuria for Cystoscopy.

PURPOSE: Only 3% to 28% of patients referred to the urology clinic for hematuria are diagnosed with bladder cancer. Cystoscopy leads to high diagnostic costs and a high patient burden. Therefore, to improve the selection of patients for cystoscopy and reduce costs and over testing we aimed to validate a recently developed diagnostic urine assay. MATERIALS AND METHODS: Included in study were 200 patients from a total of 3 European countries who underwent cystoscopy for hematuria, including 97 with bladder cancer and 103 with nonmalignant findings. Voided urine samples were collected prior to cystoscopy. DNA was extracted and analyzed for mutations in FGFR3, TERT and HRAS, and methylation of OTX1, ONECUT2 and TWIST1. Logistic regression was used to analyze the association between predictor variables and bladder cancer. RESULTS: Combining the methylation and mutation markers with age led to an AUC of 0.96 (95% CI 0.92-0.99) with 93% sensitivity and 86% specificity, and an optimism corrected AUC of 0.95. The AUC was higher for T1 or greater tumors compared to Ta tumors (0.99 vs 0.93). The AUC was also higher for high grade tumors compared to low grade tumors (1.00 vs 0.93). Overall negative predictive value was 99% based on the 5% to 10% prevalence of bladder cancer in patients with hematuria. This would lead to a 77% reduction in diagnostic cystoscopy. CONCLUSIONS: Analyzing hematuria patients for the risk of bladder cancer using novel molecular markers may lead to a reduction in diagnostic cystoscopy. Combining methylation analysis (OTX1, ONECUT2 and TWIST1) with mutation analysis (FGFR3, TERT and HRAS) and patient age resulted in a validated accurate prediction model.

Identification of TDRD1 as a direct target gene of ERG in primary prostate cancer.

Molecular classification of ERG-rearranged prostate cancer clarifies the role of TMPRSS2-ERG in the development and progression of prostate cancer. The objective of our study was to identify direct ERG target genes in ERG-rearranged prostate cancer. Two independent cohorts of primary prostate cancer (Cohort A, n=48; Cohort B, n=31), a cohort of late-stage prostate cancer (n=51) and expression array data of a cohort of primary prostate tumors from a different institute (n=128) were analyzed for expression of genes that were coexpressed with ERG overexpression. By genome-wide expression analysis and Q-RT-PCR it was shown that the gene Tudor domain containing 1 (TDRD1) was by far the strongest correlated gene with ERG overexpression in both Cohort A and B. Expression array analysis of the patient cohort from a different institute showed a large overlap in genes that were positively correlated with ERG overexpression, including TDRD1. In late-stage prostate cancer, TDRD1 was also coexpressed with ERG overexpression, although a proportion of ERG-negative late-stage samples expressed TDRD1. TDRD1 expression was not associated with ETV1 overexpression. In the prostate cancer cell line VCaP, downregulation of ERG by shRNA lead to a lower expression level of TDRD1 and resulted in a decreased activity of the TDRD1 promoter. By mutation analysis we identified a functional ERG binding site in the TDRD1 promoter. Our findings show TDRD1 as the first identified upregulated direct ERG target gene that is strongly associated with ERG overexpression in primary prostate cancer.

Conditional Pten knock-out mice: a model for metastatic phaeochromocytoma.

Phaeochromocytomas (PCCs) are neuro-endocrine tumours of the adrenal medulla that are usually benign, but approximately 10% of patients develop metastases. Malignant PCCs can only be diagnosed with certainty if metastases are present. Here we describe adrenal tumours generated in a Pten conditional knock-out (KO) mouse model. We characterized the molecular alterations in these tumours and compared them with human PCC. Thirty-two of 41 (78%) male Psa-Cre;Pten-loxP/loxP mice presented adrenal tumours that were shown to be PCC by histology and by immunohistochemical staining for enzymes in the catecholamine biosynthetic pathway. In 6 of 17 investigated mice, histological and immunohistochemical evidence was obtained for the presence of PCC lung metastases. Array comparative genomic hybridization (CGH) analysis of the primary tumours showed loss of chromosomes 6 and 19, which are syntenic to human 3p and 11q. Another frequent alteration found was gain of chromosome 15, which is syntenic to human chromosome 5. The molecular aberrations in the mouse model corresponded to the alterations found in a subtype of human PCC, suggesting that the PCC of the Pten KO mice might be representative of human PCC. The mouse model should allow further studies into the pathogenesis of human malignant PCCs and into therapeutic strategies for these tumours.

Targeted biallelic inactivation of Pten in the mouse prostate leads to prostate cancer accompanied by increased epithelial cell proliferation but not by reduced apoptosis.

The PTEN tumor suppressor gene is frequently inactivated in human tumors, including prostate cancer. Based on the Cre/loxP system, we generated a novel mouse prostate cancer model by targeted inactivation of the Pten gene. In this model, Cre recombinase was expressed under the control of the prostate-specific antigen (PSA) promoter. Conditional biallelic and monoallelic Pten knock-out mice were viable and Pten recombination was prostate-specific. Mouse cohorts were systematically characterized at 4 to 5, 7 to 9, and 10 to 14 months. A slightly increased proliferation rate of epithelial cells was observed in all prostate lobes of monoallelic Pten knock-out mice (PSA-Cre;Pten-loxP/+), but minimal pathologic changes were detected. All homozygous knock-out mice (PSA-Cre;Pten-loxP/loxP) showed an increased size of the luminal epithelial cells, large areas of hyperplasia, focal prostate intraepithelial neoplasia lesions and an increased prostate weight at 4 to 5 months. More extensive prostate intraepithelial neoplasia and focal microinvasion occurred at 7 to 9 months; invasive prostate carcinoma was detected in all male PSA-Cre;Pten-loxP/loxP mice at 10 to 14 months. At 15 to 16 months, a rare lymph node metastasis was found. In hyperplastic cells and in tumor cells, the expression of phospho-AKT was up-regulated. In hyperplastic and tumor cells, expression of luminal epithelial cell cytokeratins was up-regulated; tumor cells were negative for basal epithelial cell cytokeratins. Androgen receptor expression remained detectable at all stages of tumor development. The up-regulation of phospho-AKT correlated with an increased proliferation rate of the epithelial cells, but not with a reduced apoptosis.

A reported 20-gene expression signature to predict lymph node-positive disease at radical cystectomy for muscle-invasive bladder cancer is clinically not applicable.

BACKGROUND: Neoadjuvant chemotherapy (NAC) for muscle-invasive bladder cancer (MIBC) provides a small but significant survival benefit. Nevertheless, controversies on applying NAC remain because the limited benefit must be weight against chemotherapy-related toxicity and the delay of definitive local treatment. Therefore, there is a clear clinical need for tools to guide treatment decisions on NAC in MIBC. Here, we aimed to validate a previously reported 20-gene expression signature that predicted lymph node-positive disease at radical cystectomy in clinically node-negative MIBC patients, which would be a justification for upfront chemotherapy. METHODS: We studied diagnostic transurethral resection of bladder tumors (dTURBT) of 150 MIBC patients (urothelial carcinoma) who were subsequently treated by radical cystectomy and pelvic lymph node dissection. RNA was isolated and the expression level of the 20 genes was determined on a qRT-PCR platform. Normalized Ct values were used to calculate a risk score to predict the presence of node-positive disease. The Cancer Genome Atlas (TCGA) RNA expression data was analyzed to subsequently validate the results. RESULTS: In a univariate regression analysis, none of the 20 genes significantly correlated with node-positive disease. The area under the curve of the risk score calculated by the 20-gene expression signature was 0.54 (95% Confidence Interval: 0.44-0.65) versus 0.67 for the model published by Smith et al. Node-negative patients had a significantly lower tumor grade at TURBT (p = 0.03), a lower pT stage (p<0.01) and less frequent lymphovascular invasion (13% versus 38%, p<0.01) at radical cystectomy than node-positive patients. In addition, in the TCGA data, none of the 20 genes was differentially expressed in node-negative versus node-positive patients. CONCLUSIONS: We conclude that a 20-gene expression signature developed for nodal staging of MIBC at radical cystectomy could not be validated on a qRT-PCR platform in a large cohort of dTURBT specimens.

Prospects of Targeting the Gastrin Releasing Peptide Receptor and Somatostatin Receptor 2 for Nuclear Imaging and Therapy in Metastatic Breast Cancer.

BACKGROUND: The gastrin releasing peptide receptor (GRPR) and the somatostatin receptor 2 (SSTR2) are overexpressed on primary breast cancer (BC), making them ideal candidates for receptor-mediated nuclear imaging and therapy. The aim of this study was to determine whether these receptors are also suitable targets for metastatic BC. METHODS: mRNA expression of human BC samples were studied by in vitro autoradiography and associated with radioligand binding. Next, GRPR and SSTR2 mRNA levels of 60 paired primary BCs and metastases from different sites were measured by quantitative reverse transcriptase polymerase chain reaction. Receptor mRNA expression levels were associated with clinico-pathological factors and expression levels of primary tumors and corresponding metastases were compared. RESULTS: Binding of GRPR and SSTR radioligands to tumor tissue correlated significantly with receptor mRNA expression. High GRPR and SSTR2 mRNA levels were associated with estrogen receptor (ESR1)-positive tumors (p<0.001 for both receptors). There was no significant difference in GRPR mRNA expression of primary tumors versus paired metastases. Regarding SSTR2 mRNA expression, there was also no significant difference in the majority of cases, apart from liver and ovarian metastases which showed a significantly lower expression compared to the corresponding primary tumors (p = 0.02 and p = 0.03, respectively). CONCLUSION: Targeting the GRPR and SSTR2 for nuclear imaging and/or treatment has the potential to improve BC care in primary as well as metastatic disease.

Characterization of Heterogeneous Prostate Tumors in Targeted Pten Knockout Mice.

Previously, we generated a preclinical mouse prostate tumor model based on PSA-Cre driven inactivation of Pten. In this model homogeneous hyperplastic prostates (4-5m) developed at older age (>10m) into tumors. Here, we describe the molecular and histological characterization of the tumors in order to better understand the processes that are associated with prostate tumorigenesis in this targeted mouse Pten knockout model. The morphologies of the tumors that developed were very heterogeneous. Different histopathological growth patterns could be identified, including intraductal carcinoma (IDC), adenocarcinoma and undifferentiated carcinoma, all strongly positive for the epithelial cell marker Cytokeratin (CK), and carcinosarcomas, which were negative for CK. IDC pattern was already detected in prostates of 7-8 month old mice, indicating that it could be a precursor stage. At more than 10 months IDC and carcinosarcoma were most frequently observed. Gene expression profiling discriminated essentially two molecular subtypes, denoted tumor class 1 (TC1) and tumor class 2 (TC2). TC1 tumors were characterized by high expression of epithelial markers like Cytokeratin 8 and E-Cadherin whereas TC2 tumors showed high expression of mesenchyme/stroma markers such as Snail and Fibronectin. These molecular subtypes corresponded with histological growth patterns: where TC1 tumors mainly represented adenocarcinoma/intraductal carcinoma, in TC2 tumors carcinosarcoma was the dominant growth pattern. Further molecular characterization of the prostate tumors revealed an increased expression of genes associated with the inflammatory response. Moreover, functional markers for senescence, proliferation, angiogenesis and apoptosis were higher expressed in tumors compared to hyperplasia. The highest expression of proliferation and angiogenesis markers was detected in TC2 tumors. Our data clearly showed that in the genetically well-defined PSA-Cre;Pten-loxP/loxP prostate tumor model, histopathological, molecular and biological heterogeneity occurred during later stages of tumor development.

Distinct recognition modes of FXXLF and LXXLL motifs by the androgen receptor.

Among nuclear receptors, the androgen receptor (AR) is unique in that its ligand-binding domain (LBD) interacts with the FXXLF motif in the N-terminal domain, resembling coactivator LXXLL motifs. We compared AR- and estrogen receptor alpha-LBD interactions of the wild-type AR FXXLF motif and coactivator transcriptional intermediary factor 2 LXXLL motifs and variants of these motifs. Random mutagenesis revealed a key role for the F residues in FXXLF motifs in high-affinity and selective AR LBD interaction. The FXXLF motif in full-length AR and transcriptional intermediary factor 2 LXXLL motifs competed for an overlapping binding site. A computer model of the AR LBD/AR FXXLF complex showed that the bulky F residues are buried in a deep coactivator-binding groove. The corresponding groove in estrogen receptor alpha LBD is considerably shallower, explaining lack of binding of any of the FXXLF motifs tested. FXXLF and LXXLL motif interaction depended on different charged amino acid residues in the AR LBD present at opposite ends of the coactivator groove. In conclusion, our data demonstrate the importance of a deep hydrophobic groove and alternative usage of charged amino acids in specifying peptide binding to the AR LBD.

A bioinformatics-based functional analysis shows that the specifically androgen-regulated gene SARG contains an active direct repeat androgen response element in the first intron.

We characterized the specifically androgen-regulated gene (SARG), which is expressed in the androgen receptor (AR) and glucocorticoid receptor (GR) positive cell line lymph node carcinoma of the prostate-1F5 (LNCaP-1F5). SARG mRNA expression can be up-regulated by androgens, but not by glucocorticoids. SARG mRNA expression is high in prostate tissue. SARG is composed of four exons and spans a region of 14.5 kbp on chromosome 1q32.2. Transcripts of 5.5, 3.3 and 2.3 kb are the result of alternative polyadenylation. SARG mRNA splice variants lack exon 2 and vary in length of exon 1. The SARG protein has a length of 601 amino acids and is located in the cytoplasm. By screening the 18 kbp genomic sequence flanking the transcription start site we identified the imperfect direct repeat 5'-TGTGCTaacTGTTCT-3'in intron 1 as an active androgen response element (ARE-SARG+4.6). A 569 bp genomic DNA fragment containing this element functioned as an androgen-specific enhancer in transiently transfected LNCaP-1F5 cells. ARE-SARG+4.6 cooperated with flanking sequences for optimal activity. Inactivation of ARE-SARG+4.6 completely abolished the androgen response of the enhancer. Chromatin immunoprecipitation (ChIP) experiments showed chromatin structural changes of the enhancer in the presence of R1881. ARE-SARG+4.6 was able to bind to the androgen receptor, but not to the glucocorticoid receptor, correlating with its androgen-specific activity in transfections.

Trp53 inactivation leads to earlier phaeochromocytoma formation in pten knockout mice.

Phaeochromocytomas (PCCs) are benign neuroendocrine tumours of the adrenal medulla. Approximately 10% of PCC patients develop metastases, but this frequency is much higher in specific subtypes of patients. The reliable diagnosis of malignant PCC can only be made after identification of a metastasis. To study the effect of Trp53 inactivation on PCC pathogenesis in Pten KO mice, we investigated the adrenals of a large cohort of mice with conditional monoallelic and biallelic inactivation of Trp53 and Pten. The adrenal weights were determined for all mice, and in a proportion of these mice, immunohistochemistry for tyrosine hydroxylase and dopamine ß-hydroxylase was performed on the adrenals and corresponding lungs. Finally, comparative genomic hybridization (CGH) was performed. The histological and immunohistochemical results confirmed that the adrenal tumours were PCCs. Inactivation of one or both alleles of Trp53 resulted in earlier tumour occurrence in the Pten(loxP/loxP) mice as well as in the Pten(loxP/+) mice. In addition, lung metastases were found in up to 67% of mice. The CGH results showed that the most frequent genomic alterations were loss of chromosome 19 (86%) and gain of chromosome 15 (71%). In this study, we have shown that Pten/Trp53 KO mice showed metastatic PCC at high frequency and primary tumours occurred at younger ages in mice with Trp53 inactivation. Therefore, the present model appears to be a suitable model that might allow the preclinical study of new therapeutics for these tumours.

Accumulating progenitor cells in the luminal epithelial cell layer are candidate tumor initiating cells in a Pten knockout mouse prostate cancer model.

The PSA-Cre;Pten-loxP/loxP mouse prostate cancer model displays clearly defined stages of hyperplasia and cancer. Here, the initial stages of hyperplasia development are studied. Immunohistochemical staining showed that accumulated pAkt+ hyperplastic cells overexpress luminal epithelial cell marker CK8, and progenitor cell markers CK19 and Sca-1, but not basal epithelial cell markers. By expression profiling we identified novel hyperplastic cell markers, including Tacstd2 and Clu. Further we showed that at young age prostates of targeted Pten knockout mice contained in the luminal epithelial cell layer single pAkt+ cells, which overexpressed CK8, Sca-1, Tacstd2 and Clu; basal epithelial cells were always pAkt(-). Importantly, in the luminal epithelial cell layer of normal prostates we detected rare Clu+Tacstd2+Sca-1+ progenitor cells. These novel cells are candidate tumor initiating cells in Pten knockout mice. Remarkably, all luminal epithelial cells in the proximal region of normal prostates were Clu+Tacstd2+Sca-1+. However, in PSA-Cre;Pten-loxP/loxP mice, the proximal prostate does not contain hyperplastic foci. Small hyperplastic foci in prostates of PSA-Cre;Pten-loxP/+ mice found at old age, showed complete Pten inactivation and a progenitor marker profile. Finally, we present a novel model of prostate development and renewal, including lineage-specific luminal epithelial progenitor cells. It is proposed that Pten deficiency induces a shift in the balance of differentiation to proliferation in these cells.

Truncated ETV1, fused to novel tissue-specific genes, and full-length ETV1 in prostate cancer.

In this study, we describe the properties of novel ETV1 fusion genes, encoding N-truncated ETV1 (dETV1), and of full-length ETV1, overexpressed in clinical prostate cancer. We detected overexpression of novel ETV1 fusion genes or of full-length ETV1 in 10% of prostate cancers. Novel ETV1 fusion partners included FOXP1, an EST (EST14), and an endogenous retroviral repeat sequence (HERVK17). Like TMPRSS2, EST14 and HERVK17 were prostate-specific and androgen-regulated expressed. This unique expression pattern of most ETV1 fusion partners seems an important determinant in prostate cancer development. In transient reporter assays, full-length ETV1 was a strong transactivator, whereas dETV1 was not. However, several of the biological properties of dETV1 and full-length ETV1 were identical. On stable overexpression, both induced migration and invasion of immortalized nontumorigenic PNT2C2 prostate epithelial cells. In contrast to dETV1, full-length ETV1 also induced anchorage-independent growth of these cells. PNT2C2 cells stably transfected with dETV1 or full-length ETV1 expression constructs showed small differences in induced expression of target genes. Many genes involved in tumor invasion/metastasis, including uPA/uPAR and MMPs, were up-regulated in both cell types. Integrin beta3 (ITGB3) was clearly up-regulated by full-length ETV1 but much less by dETV1. Based on the present data and on previous findings, a novel concept of the role of dETV1 and of full-length ETV1 overexpression in prostate cancer is proposed.

Broadened ligand responsiveness of androgen receptor mutants obtained by random amino acid substitution of H874 and mutation hot spot T877 in prostate cancer.

In a subset of endocrine therapy-resistant prostate cancers, amino acid substitutions H874Y, T877A and T877S, which broaden ligand specificity of the ligand binding domain (LBD) of the androgen receptor (AR), have been detected. To increase our knowledge of the role of amino acid substitutions at these specific positions in prostate cancer, codons 874 and 877 were subjected to random mutagenesis. AR mutants were screened in a yeast readout system for responsiveness to 5 alpha-dihydrotestosterone, progesterone and dehydroepiandrosterone. At position 874, only the histidine to tyrosine substitution could broaden AR ligand specificity. At position 877, 4 ligand specificity broadening substitutions were found: T877A, T877S, T877C and T877G. The latter 2 were not found in prostate cancer. The AR mutants were tested in mammalian (Hep3B) cells for responsiveness to 13 different ligands. All mutants displayed their own ligand specificity spectrum. Importantly, AR(H874Y) and AR(T877A) could be activated by cortisol. According to the 3-dimensional structure of the AR LBD, T877 interacts directly with the 17 beta-hydroxyl group of androgens. All amino acid substitutions identified at position 877 had smaller side chains than the threonine in the wild-type receptor, indicating that increased space in the ligand binding pocket is important in broadened ligand specificity. Because H874 does not interact directly with the ligand, its substitution by a tyrosine is expected to change the ligand binding pocket conformation indirectly. For T877C and T877G substitutions, 2-point mutations are required, and for H874Y, T877A and T877S substitutions, only a 1-point mutation is sufficient. This most likely explains that the latter 3 have been found in prostate cancer.