Genome-wide analysis of androgen receptor binding and gene regulation in two CWR22-derived prostate cancer cell lines

Prostate carcinoma (CaP) is a heterogeneous multifocal disease where gene expression and regulation are altered not only with disease progression but also between metastatic lesions. The androgen receptor (AR) regulates the growth of metastatic CaPs; however, sensitivity to androgen ablation is short lived, yielding to emergence of castrate-resistant CaP (CRCaP). CRCaP prostate cancers continue to express the AR, a pivotal prostate regulator, but it is not known whether the AR targets similar or different genes in different castrate-resistant cells. In this study, we investigated AR binding and AR-dependent transcription in two related castrate-resistant cell lines derived from androgen-dependent CWR22-relapsed tumors: CWR22Rv1 (Rv1) and CWR-R1 (R1). Expression microarray analysis revealed that R1 and Rv1 cells had significantly different gene expression profiles individually and in response to androgen. In contrast, AR chromatin immunoprecipitation (ChIP) combined with promoter DNA microarrays (ChIP-on-chip) studies showed that they have a similar AR-binding profile. Coupling of the microarray study with ChIP-on-chip analysis identified direct AR targets. The most prominent function of transcripts that were direct AR targets was transcriptional regulation, although only one transcriptional regulator, CCAAT/enhancer binding protein δ, was commonly regulated in both lines. Our results indicate that the AR regulates the expression of different transcripts in the two lines, and demonstrate the versatility of the AR-regulated gene expression program in prostate tumors.

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Identification of Genomic Classifiers That Distinguish Induction Failure in T-Lineage Acute Lymphoblastic Leukemia in COG Study 9404.

Blood ◽

10.1182/blood.v108.11.1826.1826 ◽

2006 ◽

Vol 108 (11) ◽

pp. 1826-1826

Author(s):

Stuart S. Winter ◽

Hadya Khawaja ◽

Zeyu Jiang ◽

Timothy Griffin ◽

Barbara Asselin ◽

...

Keyword(s):

Gene Expression ◽

Drug Resistance ◽

Acute Lymphoblastic Leukemia ◽

Cell Lines ◽

Expression Profiles ◽

Lymphoblastic Leukemia ◽

Gene Expression Profiles ◽

Resistant Cell ◽

Acquired Drug Resistance ◽

Induction Failure

Abstract The clinical features of age, white count, and presence of extramedullary disease cannot predict risk for induction failure (IF) in patients who present with T-cell acute lymphoblastic leukemia (T-ALL). On the basis of recent observations that gene expression profiles can distinguish clinicopathologic cohorts of patients with acute leukemia, we hypothesized that microarray analyses performed on diagnostic T-ALL bone marrow samples might identify a genomic classifier for IF patients. Using a case-control study design for children and young adults treated for T-ALL on Children’s Oncology Group Study 9404, we analyzed 50 cryopreserved T-ALL samples using Affymetrix U133A Plus 2 genechips, which have 54,000 genes, ESTs and genomic classifiers. Following RMA normalization, we used Prognostic Multi-array Analysis (PAM) to identify a 116-member genomic classifier that could accurately identify all 6 IF cases from the 44 patients who achieved remission. Within the IF cohort, 37 genes were up-regulated and 79 were down-regulated in comparison to other outcome groups. To further investigate the genetic mechanisms governing IF, we developed four cell lines with acquired drug resistance: Jurkat and Sup T1; each having resistance to daunorubicin (DNR) and asparaginase (ASP). Using a comparative analysis for fold-change in gene expression among 6 IF patients and the T-ALL DNR and ASP-resistant cell lines, we identified seven genes that were up-regulated, and another set of seven genes that were commonly down-regulated. To validate the potential use of our 116-member gene set in predicting IF in T-ALL, we tested our genomic classifier in 42 cases which were treated on COG study 8704 and hybridized to the Affymetrix U133Av.2 chip. Because only 85 probes were shared between U133A Plus 2 and U133Av. 2 chips, we employed shrunken class centroids to constrain our classifier to 25 rank-ordered probes. This smaller classifier correctly identified the single IF case in 8704, as well as another patient who was an early treatment failure, indicating that similar genomic classifiers may identify IF patients in different clinical trials. These results indicate that genetic profiling may be useful in prospectively identifying IF patients in T-ALL. In addition, we identified genes that were commonly upregulated in IF patients and T-ALL cell lines with intrinsic drug resistance.

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Histone Deacetylase Inhibition Using LBH589 Is Effective in Lymphoma and Results in Down-Regulation of the NF-KB Pathway.

Blood ◽

10.1182/blood.v114.22.3730.3730 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3730-3730 ◽

Cited By ~ 2

Author(s):

Jason L. Smith ◽

Amee Patel ◽

Siyao Fan ◽

Cassandra L. Jacobs ◽

Katherine J. Walsh ◽

...

Keyword(s):

Gene Expression ◽

B Cell ◽

Cell Lines ◽

Expression Profiles ◽

Hdac Inhibitors ◽

Gene Expression Profiles ◽

Resistant Cell ◽

Hdac Inhibition ◽

Down Regulation ◽

Highly Sensitive

Abstract Abstract 3730 Poster Board III-666 Background Histone deacetylase (HDAC) inhibition has emerged as a promising therapeutic approach in malignancies. HDAC inhibition has proved to be a particularly effective option in patients with lymphoma. The HDAC inhibitor vorinostat is approved for the treatment of patients with cutaneous T-cell lymphomas and is being tested in patients with B cell lymphomas. More recently, a number of other HDAC inhibitors have entered preclinical and clinical testing. The mechanisms through which HDAC inhibitors exert their downstream effects are currently unknown. As the number of HDAC inhibitors in development increases, it is unclear if they share a class effect or display unique mechanisms of action. Recently, LBH589 has been described as an orally available, highly potent inhibitor of HDAC. We decided to explore whether LBH589 would be an effective therapeutic option for patients with lymphoma. Methods and Results In order to evaluate whether LBH was efficacious and potent in B cell lymphomas, we tested both vorinostat and LBH589 in the same cell line(s). We found that LBH589 was over 10 times more potent than vorinostat (mean IC50 7.4nM versus 830nM). We decided to further test LBH589 in an expanded panel of 18 cell lines derived from 5 different lymphoid malignancies: Burkitt lymphoma, mantle cell lymphoma, Hodgkin lymphoma, multiple myeloma and diffuse large B cell lymphoma. LBH589 was found to be lethal in each of these cell lines at IC50 concentrations varying from 5.6-31.5 nM (mean 11.2nM), suggesting that this drug may be effective at physiologically achievable concentrations. Based on the IC50 cut-off of 10nM, we assigned the treated cell lines to 2 groups: highly sensitive (IC50 < 10nM, N=11) and less sensitive (IC50> 10nM, N=8). We performed gene expression profiling on 12 of these cell lines and compared the gene expression profiles of the highly sensitive versus less sensitive cell lines. Further, we performed time course experiments in which we evaluated the effects of LBH589 at its IC50 on cell lines at 6 and 12 hours post-treatment. Gene expression profiling was performed on the treated cells at each time point. We also engineered resistant cell lines by incremental dose escalation over a period of months to a concentration greater than or equal to the IC50. The resistant cell lines were also profiled for gene expression and compared to the wild type cell lines. The gene expression profiles of LBH589 treated cells at 6 and 12 hours demonstrated a clear and progressive down regulation of genes associated with the NF-KB pathway (Figure 1). Furthermore, cell lines with high expression of genes in the NF-KB pathway were uniformly highly sensitive to LBH589 with IC50<10nM in all cases. Conclusion NF-KB activation is a common feature of many different lymphoma types. Our data suggest that HDAC inhibition using LBH589 could provide a potent method for treating lymphomas and that HDAC inhibitors may exert their effects through the down-regulation of the NF-KB pathway. Our data also suggest a rationale for dual inhibition of HDAC and NF-KB in the treatment of lymphoma. Disclosures: Rizzieri: Merck & Co., Inc.: Consultancy.

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