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author:("Cao, duzhong")
1.  Integrative clinical sequencing in the management of children and young adults with refractory or relapsed cancer 
JAMA  2015;314(9):913-925.
Cancer is caused by a diverse array of somatic and germline genomic aberrations. Advances in genomic sequencing technologies have improved the ability to detect these molecular aberrations with greater sensitivity. However, integrating them into clinical management in an individualized manner has proven challenging.
To evaluate the use of integrative clinical sequencing and genetic counseling in the assessment and treatment of children and young adults with cancer.
Design, Settings and Participants
An observational, consecutive case series (May 2012–October 2014) of 102 children and young adults (mean age, 10.6; median age, 11.5, range: 0–22 years) with relapsed, refractory, or rare cancer at a single major academic medical center.
Each participant underwent integrative clinical exome (tumor and germline DNA) and transcriptome (tumor RNA) sequencing along with genetic counseling. Results were discussed in a multi-disciplinary Precision Medicine Tumor Board (PMTB) and recommendations were reported to treating physicians and families.
Main Outcomes and Measures
Proportion of patients with potentially actionable findings (PAF), results of clinical actions based on integrative clinical sequencing (ICS), and estimated proportion of patients or their families at risk for future cancer. PAF was defined as any genomic findings discovered during sequencing analysis that could lead to a 1) change in patient management by providing a targetable molecular aberration, 2) change in diagnosis or risk stratification or 3) provides cancer-related germline findings, which inform patients/families about a potential future risk of various cancers;
We screened 104 patients and enrolled 102 patients of which 91 (89%) had adequate tumor tissue available to complete sequencing and only these patients were included in all subsequent calculations, including 28 (31%) with hematological malignancies and 63 (69%) with solid tumors. Overall, 42 (46%) patients had PAFs which changed patient management including, 54% (15/28) with hematological malignancies and 43% (27/63) with solid tumors. Overall, individualized actions were taken in 23 of the 91 (25%) patients and families based on actionable ICS findings, including change in treatment in 14 (15%) and genetic counseling for future cancer risk in 9 (10%) patients. 9/91 (10%) of these personalized clinical interventions resulted in ongoing partial clinical remission of 8–16 months duration or help sustain complete clinical remission of 6–21 months duration. All 9 (10%) patients and families with actionable incidental genetic findings agreed to formal genetic counseling and screening.
Conclusions and Relevance
In this single center case series of children and young adults with relapsed or refractory cancer, incorporation of data from integrative clinical sequencing into clinical management was feasible, revealed potentially actionable findings in 46% of patients, and was associated with change in treatment and family genetic counseling in a small proportion of patients. The lack of a control group limited our ability to judge whether better clinical outcomes were achieved compared to standard care.
PMCID: PMC4758114  PMID: 26325560
precision medicine; clinical sequencing; pediatric cancers; whole exome sequencing; transcriptome sequencing
2.  Mechanistic Support for Combined MET and AR Blockade in Castration-Resistant Prostate Cancer12 
Neoplasia (New York, N.Y.)  2016;18(1):1-9.
A recent phase III trial of the MET kinase inhibitor cabozantinib in men with castration-resistant prostate cancer (CRPC) failed to meet its primary survival end point; however, most men with CRPC have intact androgen receptor (AR) signaling. As previous work supports negative regulation of MET by AR signaling, we hypothesized that intact AR signaling may have limited the efficacy of cabozantinib in some of these patients. To assess the role of AR signaling on MET inhibition, we first performed an in silico analysis of human CRPC tissue samples stratified by AR signaling status (+ or −), which identified MET expression as markedly increased in AR− samples. In vitro, AR signaling inhibition in AR+ CRPC models increased MET expression and resulted in susceptibility to ligand (HGF) activation. Likewise, MET inhibition was only effective in blocking cancer phenotypes in cells with MET overexpression. Using multiple AR+ CRPC in vitro and in vivo models, we showed that combined cabozantinib and enzalutamide (AR antagonist) treatment was more efficacious than either inhibitor alone. These data provide a compelling rationale to combine AR and MET inhibition in CRPC and may explain the negative results of the phase III cabozantinib study in CRPC. Similarly, the expression of MET in AR− disease, whether due to AR inhibition or loss of AR signaling, suggests potential utility for MET inhibition in select patients with AR therapy resistance and in AR− prostate cancer.
PMCID: PMC4735600  PMID: 26806347
3.  Targeting the MLL complex in castration resistant prostate cancer 
Nature medicine  2015;21(4):344-352.
Resistance to androgen deprivation therapies and increased androgen receptor (AR) activity are major drivers of castration resistant prostate cancer (CRPC). Although prior work focused on targeting AR directly, co-activators of AR signaling—which may represent new therapeutic targets—are relatively underexplored. Here we demonstrate that the mixed-lineage leukemia (MLL) complex, a well-known driver of MLL-fusion-positive leukemia, acts as a co-activator of AR signaling. AR directly interacts with the MLL complex via the menin MLL subunit. Menin expression is higher in castration resistant prostate cancer compared to hormone naïve prostate cancer and benign prostate and high menin expression correlates with poor overall survival. Treatment with a small molecule inhibitor of the menin-MLL interaction blocks AR signaling and inhibits the growth of castration resistant tumors in vivo in mice. Taken together, this work identifies the MLL complex as a critical co-activator of AR and a potential therapeutic target in advanced prostate cancer.
PMCID: PMC4390530  PMID: 25822367
Androgen deprivation; prostate cancer; MLL complex; menin; androgen receptor
4.  Prostate Cancer Cell–Stromal Cell Cross-Talk via FGFR1 Mediates Antitumor Activity of Dovitinib in Bone Metastases 
Science translational medicine  2014;6(252):252ra122.
Bone is the most common site of prostate cancer (PCa) progression to a therapy-resistant, lethal phenotype. We found that blockade of fibroblast growth factor receptors (FGFRs) with the receptor tyrosine kinase inhibitor dovitinib has clinical activity in a subset of men with castration-resistant PCa and bone metastases. Our integrated analyses suggest that FGF signaling mediates a positive feedback loop between PCa cells and bone cells and that blockade of FGFR1 in osteoblasts partially mediates the antitumor activity of dovitinib by improving bone quality and by blocking PCa cell–bone cell interaction. These findings account for clinical observations such as reductions in lesion size and intensity on bone scans, lymph node size, and tumor-specific symptoms without proportional declines in prostate-specific antigen concentration. Our findings suggest that targeting FGFR has therapeutic activity in advanced PCa and provide direction for the development of therapies with FGFR inhibitors.
PMCID: PMC4407499  PMID: 25186177
5.  The Landscape of Long Noncoding RNAs in the Human Transcriptome 
Nature genetics  2015;47(3):199-208.
Long non-coding RNAs (lncRNAs) are emerging as important regulators of tissue physiology and disease processes including cancer. In order to delineate genome-wide lncRNA expression, we curated 7,256 RNA-Seq libraries from tumors, normal tissues, and cell lines comprising over 43 terabases of sequence from 25 independent studies. We applied ab initio assembly methodology to this dataset, yielding a consensus human transcriptome of 91,013 expressed genes. Over 68% (58,648) of genes were classified as lncRNAs, of which 79% (48,952) were previously unannotated. About 1% (597) of the lncRNAs harbored ultraconserved elements and 7% (3,900) overlapped disease-associated single nucleotide polymorphisms (SNPs). To prioritize lineage-specific, disease-associated lncRNA expression we employed non-parametric differential expression testing and nominated 7,942 lineage- or cancer-associated lncRNA genes. The lncRNA landscape characterized here may shed light into normal biology and cancer pathogenesis, and be valuable for future biomarker development.
PMCID: PMC4417758  PMID: 25599403
cancer; long noncoding RNA (lncRNA); high-throughput RNA sequencing (RNA-Seq); transcriptome; transcriptome assembly; Sample Set Enrichment Analysis (SSEA); MiTranscriptome
6.  The lncRNA PCAT29 Inhibits Oncogenic Phenotypes in Prostate Cancer 
Molecular cancer research : MCR  2014;12(8):1081-1087.
Long noncoding RNAs (lncRNAs) have recently been associated with the development and progression of a variety of human cancers. However, to date, the interplay between known oncogenic or tumor suppressive events and lncRNAs has not been well described. Here the novel lncRNA, Prostate Cancer-Associated Transcript 29 (PCAT29), is characterized along with its relationship to the androgen receptor (AR). PCAT29 is suppressed by dihydrotestosterone (DHT) and upregulated upon castration therapy in a prostate cancer xenograft model. PCAT29 knockdown significantly increased proliferation and migration of prostate cancer cells, while PCAT29 overexpression conferred the opposite effect and suppressed growth and metastases of prostate tumors in chick chorioallantoic membrane (CAM) assays. Finally, in prostate cancer patient specimens, low PCAT29 expression correlated with poor prognostic outcomes. Taken together these data expose PCAT29 as an androgen-regulated tumor suppressor in prostate cancer.
PMCID: PMC4135019  PMID: 25030374
7.  Transcriptome Meta-Analysis of Lung Cancer Reveals Recurrent Aberrations in NRG1 and Hippo Pathway Genes 
Nature communications  2014;5:5893.
Lung cancer is emerging as a paradigm for disease molecular subtyping, facilitating targeted therapy based on driving somatic alterations. Here, we perform transcriptome analysis of 153 samples representing lung adenocarcinomas, squamous cell carcinomas, large cell lung cancer, adenoid cystic carcinomas and cell lines. By integrating our data with The Cancer Genome Atlas and published sources, we analyze 753 lung cancer samples for gene fusions and other transcriptomic alterations. We show that higher numbers of gene fusions is an independent prognostic factor for poor survival in lung cancer. Our analysis confirms the recently reported CD74-NRG1 fusion and suggests that NRG1, NF1 and Hippo pathway fusions may play important roles in tumors without known driver mutations. In addition, we observe exon skipping events in c-MET, which are attributable to splice site mutations. These classes of genetic aberrations may play a significant role in the genesis of lung cancers lacking known driver mutations.
PMCID: PMC4274748  PMID: 25531467
8.  Frequent Discordance between ERG Gene Rearrangement and ERG Protein Expression in a Rapid Autopsy Cohort of Patients with Lethal, Metastatic, Castration-Resistant Prostate Cancer 
The Prostate  2014;74(12):1199-1208.
ERG rearrangements in localized prostate cancer can be detected with high sensitivity and specificity by immunohistochemistry (IHC). However, recent data suggests that ERG IHC may be less sensitive for ERG rearrangements in castration-resistant prostate cancer (CRPC). Thus, we sought to examine ERG protein expression in a cohort of rapid autopsy patients with lethal metastatic CRPC (mCRPC).
A tissue microarray (TMA) of tumor sites from these patients was evaluated for ERG, prostate specific antigen (PSA), and androgen receptor (AR) expression by IHC and correlated with ERG rearrangement status by fluorescent in situ hybridization (FISH). IHC was scored as the product of tumor cell staining intensity (0–3) and percentage of cells positive (0–100) (overall product score range = 0–300).
All sixteen (100%) ERG rearrangement negative (ERGneg) patients were also negative for ERG tumor cell expression (i.e., IHC product score = 0). Of the ten ERG rearrangement positive (ERGpos) patients, two (20%) were completely negative for ERG tumor cell expression, while eight (80%) had weak ERG expression (median IHC product score = 5–110). Of these eight ERGpos patients, five (63%) had at least one tumor site without any detectable ERG expression. For a given ERGpos patient, ERG expression varied both between and within tumor sites; AR and PSA expression also varied between tumor sites, and there was no significant correlation between ERG and AR or PSA expression.
These data reveal frequent discordance between ERG IHC and ERG FISH in ERGpos patients from this unique cohort of heavily-treated lethal mCRPC.
PMCID: PMC4156519  PMID: 25043157
TMPRSS2-ERG; androgen receptor (AR); immunohistochemistry (IHC); fluorescent in situ hybridization (FISH); rapid autopsy
9.  Therapeutic Targeting of BET Bromodomain Proteins in Castration-Resistant Prostate Cancer 
Nature  2014;510(7504):278-282.
Men who develop metastatic castration-resistant prostate cancer (CRPC) invariably succumb to the disease. The development and progression to CRPC following androgen ablation therapy is predominantly driven by unregulated androgen receptor (AR) signaling1-3. Despite the success of recently approved therapies targeting AR signaling such as abiraterone4-6 and second generation anti-androgens MDV3100 (enzalutamide)7,8, durable responses are limited, presumably due to acquired resistance. Recently JQ1 and I-BET, two selective small molecule inhibitors that target the amino-terminal bromodomains of BRD4, have been shown to exhibit anti-proliferative effects in a range of malignancies9-12. Here we show that AR signaling-competent CRPC cell lines are preferentially sensitive to BET bromodomain inhibition. BRD4 physically interacts with the N-terminal domain of AR and can be disrupted by JQ111,13. Like the direct AR antagonist, MDV3100, JQ1 disrupted AR recruitment to target gene loci. In contrast to MDV3100, JQ1 functions downstream of AR, and more potently abrogated BRD4 localization to AR target loci and AR-mediated gene transcription including induction of TMPRSS2-ERG and its oncogenic activity. In vivo, BET bromodomain inhibition was more efficacious than direct AR antagonism in CRPC xenograft models. Taken together, these studies provide a novel epigenetic approach for the concerted blockade of oncogenic drivers in advanced prostate cancer.
PMCID: PMC4075966  PMID: 24759320
10.  A Novel RNA In Situ Hybridization Assay for the Long Noncoding RNA SChLAP1 Predicts Poor Clinical Outcome After Radical Prostatectomy in Clinically Localized Prostate Cancer12 
Neoplasia (New York, N.Y.)  2014;16(12):1121-1127.
Long noncoding RNAs (lncRNAs) are an emerging class of oncogenic molecules implicated in a diverse range of human malignancies. We recently identified SChLAP1 as a novel lncRNA that demonstrates outlier expression in a subset of prostate cancers, promotes tumor cell invasion and metastasis, and associates with lethal disease. Based on these findings, we sought to develop an RNA in situ hybridization (ISH) assay for SChLAP1 to 1) investigate the spectrum of SChLAP1 expression from benign prostatic tissue to metastatic castration-resistant prostate cancer and 2) to determine whether SChLAP1 expression by ISH is associated with outcome after radical prostatectomy in patients with clinically localized disease. The results from our current study demonstrate that SChLAP1 expression increases with prostate cancer progression, and high SChLAP1 expression by ISH is associated with poor outcome after radical prostatectomy in patients with clinically localized prostate cancer by both univariate (hazard ratio = 2.343, P = .005) and multivariate (hazard ratio = 1.99, P = .032) Cox regression analyses. This study highlights a potential clinical utility for SChLAP1 ISH as a novel tissue-based biomarker assay for outcome prognostication after radical prostatectomy.
PMCID: PMC4309259  PMID: 25499224
11.  The Central Role of EED in the Orchestration of Polycomb Group Complexes 
Nature communications  2014;5:3127.
Polycomb Repressive Complexes 1 and 2 (PRC1 and 2) play a critical role in the epigenetic regulation of transcription during cellular differentiation, stem cell pluripotency, and neoplastic progression. Here we show that the Polycomb Group protein EED, a core component of PRC2, physically interacts with and functions as part of PRC1. Components of PRC1 and PRC2 compete for EED binding. EED functions to recruit PRC1 to H3K27me3 loci and enhances PRC1 mediated H2A ubiquitin E3 ligase activity. Taken together, we suggest an integral role for EED as an epigenetic exchange factor coordinating the activities of PRC1 and 2.
PMCID: PMC4073494  PMID: 24457600
12.  Reconstructing targetable pathways in lung cancer by integrating diverse omics data 
Nature communications  2013;4:2617.
Global ‘multi-omics’ profiling of cancer cells harbours the potential for characterizing the signaling networks associated with specific oncogenes. Here we profile the transcriptome, proteome and phosphoproteome in a panel of non-small cell lung cancer (NSCLC) cell lines in order to reconstruct targetable networks associated with KRAS dependency. We develop a two-step bioinformatics strategy addressing the challenge of integrating these disparate data sets. We first define an ‘abundance-score’ combining transcript, protein and phospho-protein abundances to nominate differentially abundant proteins and then use the Prize Collecting Steiner Tree algorithm to identify functional sub-networks. We identify three modules centered on KRAS and MET, LCK and PAK1 and b-Catenin. We validate activation of these proteins in KRAS-dependent (KRAS-Dep) cells and perform functional studies defining LCK as a critical gene for cell proliferation in KRAS-Dep but not KRAS-independent NSCLCs. These results suggest that LCK is a potential druggable target protein in KRAS-Dep lung cancers.
PMCID: PMC4107456  PMID: 24135919
15.  Outlier Kinase Expression by RNA Sequencing as Targets for Precision Therapy 
Cancer discovery  2013;3(3):280-293.
Protein kinases represent the most effective class of therapeutic targets in cancer; therefore determination of kinase aberrations is a major focus of cancer genomic studies. Here, we analyzed transcriptome sequencing data from a compendium of 482 cancer and benign samples from 25 different tissue types, and defined distinct ‘outlier kinases’ in individual breast and pancreatic cancer samples, based on highest levels of absolute and differential expression. Frequent outlier kinases in breast cancer included therapeutic targets like ERBB2 and FGFR4, distinct from MET, AKT2, and PLK2 in pancreatic cancer. Outlier kinases imparted sample-specific dependencies in various cell lines as tested by siRNA knockdown and/or pharmacologic inhibition. Outlier expression of polo-like kinases was observed in a subset of KRAS-dependent pancreatic cancer cell lines, and conferred increased sensitivity to the pan-PLK inhibitor BI 6727. Our results suggest that outlier kinases represent effective precision therapeutic targets that are readily identifiable through RNA-sequencing of tumors.
PMCID: PMC3597439  PMID: 23384775
Pancreatic Cancer; RNA-Seq; Kinases; Outlier Expression; Personalized Medicine
17.  Identification of Targetable FGFR Gene Fusions in Diverse Cancers 
Cancer discovery  2013;3(6):636-647.
Through a prospective clinical sequencing program for advanced cancers, four index cases were identified which harbor gene rearrangements of FGFR2 including patients with cholangiocarcinoma, breast cancer, and prostate cancer. After extending our assessment of FGFR rearrangements across multiple tumor cohorts, we identified additional FGFR gene fusions with intact kinase domains in lung squamous cell cancer, bladder cancer, thyroid cancer, oral cancer, glioblastoma, and head and neck squamous cell cancer. All FGFR fusion partners tested exhibit oligomerization capability, suggesting a shared mode of kinase activation. Overexpression of FGFR fusion proteins induced cell proliferation. Two bladder cancer cell lines that harbor FGFR3 fusion proteins exhibited enhanced susceptibility to pharmacologic inhibition in vitro and in vivo. Due to the combinatorial possibilities of FGFR family fusion to a variety of oligomerization partners, clinical sequencing efforts which incorporate transcriptome analysis for gene fusions are poised to identify rare, targetable FGFR fusions across diverse cancer types.
PMCID: PMC3694764  PMID: 23558953
MI-ONCOSEQ; integrative clinical sequencing; FGFR fusions; driver mutations; therapeutic targets
18.  Identification of Recurrent NAB2-STAT6 Gene Fusions in Solitary Fibrous Tumor by Integrative Sequencing 
Nature genetics  2013;45(2):180-185.
A 44-year old woman with recurrent solitary fibrous tumor (SFT)/hemangiopericytoma was enrolled in a clinical sequencing program including whole exome and transcriptome sequencing. A gene fusion of the transcriptional repressor NAB2 with the transcriptional activator STAT6 was detected. Transcriptome sequencing of 27 additional SFTs all revealed the presence of a NAB2-STAT6 gene fusion. Using RT-PCR and sequencing, we detected this fusion in 51 of 51 SFTs, indicating high levels of recurrence. Expression of NAB2-STAT6 fusion proteins was confirmed in SFT, and the predicted fusion products harbor the early growth response (EGR)-binding domain of NAB2 fused to the activation domain of STAT6. Overexpression of the NAB2-STAT6 gene fusion induced proliferation in cultured cells and activated EGR-responsive genes. These studies establish NAB2-STAT6 as the defining driver mutation of SFT and provide an example of how neoplasia can be initiated by converting a transcriptional repressor of mitogenic pathways into a transcriptional activator.
PMCID: PMC3654808  PMID: 23313952
19.  Comprehensive Analysis of ETS Family Members in Melanoma by Fluorescence In Situ Hybridization Reveals Recurrent ETV1 Amplification 
Translational Oncology  2013;6(4):405-412.
E26 transformation-specific (ETS) transcription factors are known to be involved in gene aberrations in various malignancies including prostate cancer; however, their role in melanoma oncogenesis has yet to be fully explored. We have completed a comprehensive fluorescence in situ hybridization (FISH)-based screen for all 27 members of the ETS transcription factor family on two melanoma tissue microarrays, representing 223 melanomas, 10 nevi, and 5 normal skin tissues. None of the melanoma cases demonstrated ETS fusions; however, 6 of 114 (5.3%) melanomas were amplified for ETV1 using a break-apart FISH probe. For the six positive cases, locus-controlled FISH probes revealed that two of six cases were amplified for the ETV1 region, whereas four cases showed copy gains of the entire chromosome 7. The remaining 26 ETS family members showed no chromosomal aberrations by FISH. Quantitative polymerase chain reaction showed an average 3.4-fold (P value = .00218) increased expression of ETV1 in melanomas, including the FISH ETV1-amplified cases, when compared to other malignancies (prostate, breast, and bladder carcinomas). These data suggest that a subset of melanomas overexpresses ETV1 and amplification of ETV1 may be one mechanism for achieving high gene expression.
PMCID: PMC3730015  PMID: 23908683
20.  Characterization of the EZH2-MMSET Histone Methyltransferase Regulatory Axis in Cancer 
Molecular cell  2012;49(1):80-93.
Histone methyltransferases (HMTases), as chromatin modifiers, regulate the transcriptomic landscape in normal development as well in diseases such as cancer. Here, we molecularly order two HMTases, EZH2 and MMSET that have established genetic links to oncogenesis. EZH2, which mediates histone H3K27 trimethylation and is associated with gene silencing, was shown to be coordinately expressed and function upstream of MMSET, which mediates H3K36 dimethylation and is associated with active transcription. We found that the EZH2-MMSET HMTase axis is coordinated by a microRNA network and that the oncogenic functions of EZH2 require MMSET activity. Together, these results suggest that the EZH2-MMSET HMTase axis coordinately functions as a master regulator of transcriptional repression, activation, and oncogenesis and may represent an attractive therapeutic target in cancer.
PMCID: PMC3547524  PMID: 23159737
21.  Expressed Pseudogenes in the Transcriptional Landscape of Human Cancers 
Cell  2012;149(7):1622-1634.
Pseudogene transcripts can provide a novel tier of gene regulation through generation of endogenous siRNAs or miRNA-binding sites. Characterization of pseudogene expression, however, has remained confined to anecdotal observations due to analytical challenges posed by the extremely close sequence similarity with their counterpart coding genes. Here, we describe a systematic analysis of pseudogene “transcription” from an RNA-Seq resource of 293 samples, representing 13 cancer and normal tissue types, and observe a surprisingly prevalent, genome-wide expression of pseudogenes that could be categorized as ubiquitously expressed or lineage and/or cancer specific. Further, we explore disease subtype specificity and functions of selected expressed pseudogenes. Taken together, we provide evidence that transcribed pseudogenes are a significant contributor to the transcriptional landscape of cells and are positioned to play significant roles in cellular differentiation and cancer progression, especially in light of the recently described ceRNA networks. Our work provides a transcriptome resource that enables high-throughput analyses of pseudogene expression.
PMCID: PMC3597446  PMID: 22726445
22.  The Mutational Landscape of Lethal Castrate Resistant Prostate Cancer 
Nature  2012;487(7406):239-243.
Characterization of the prostate cancer transcriptome and genome has identified chromosomal rearrangements and copy number gains/losses, including ETS gene fusions, PTEN loss and androgen receptor (AR) amplification, that drive prostate cancer development and progression to lethal, metastatic castrate resistant prostate cancer (CRPC)1. As less is known about the role of mutations2–4, here we sequenced the exomes of 50 lethal, heavily-pretreated metastatic CRPCs obtained at rapid autopsy (including three different foci from the same patient) and 11 treatment naïve, high-grade localized prostate cancers. We identified low overall mutation rates even in heavily treated CRPC (2.00/Mb) and confirmed the monoclonal origin of lethal CRPC. Integrating exome copy number analysis identified disruptions of CHD1, which define a subtype of ETS fusionnegative prostate cancer. Similarly, we demonstrate that ETS2, which is deleted in ~1/3 of CRPCs (commonly through TMPRSS2:ERG fusions), is also deregulated through mutation. Further, we identified recurrent mutations in multiple chromatin/histone modifying genes, including MLL2 (mutated in 8.6% of prostate cancers), and demonstrate interaction of the MLL complex with AR, which is required for AR-mediated signaling. We also identified novel recurrent mutations in the AR collaborating factor FOXA1, which is mutated in 5 of 147 (3.4%) prostate cancers (both untreated localized prostate cancer and CRPC), and showed that mutated FOXA1 represses androgen signaling and increases tumour growth. Proteins that physically interact with AR, such as the ERG gene fusion product, FOXA1, MLL2, UTX, and ASXL1 were found to be mutated in CRPC. In summary, we describe the mutational landscape of a heavily treated metastatic cancer, identify novel mechanisms of AR signaling deregulated in prostate cancer, and prioritize candidates for future study.
PMCID: PMC3396711  PMID: 22722839
23.  Personalized Oncology Through Integrative High-Throughput Sequencing: A Pilot Study 
Science translational medicine  2011;3(111):111ra121.
Individual cancers harbor a set of genetic aberrations that can be informative for identifying rational therapies currently available or in clinical trials. We implemented a pilot study to explore the practical challenges of applying high-throughput sequencing in clinical oncology. We enrolled patients with advanced or refractory cancer who were eligible for clinical trials. For each patient, we performed whole-genome sequencing of the tumor, targeted whole-exome sequencing of tumor and normal DNA, and transcriptome sequencing (RNA-Seq) of the tumor to identify potentially informative mutations in a clinically relevant time frame of 3 to 4 weeks. With this approach, we detected several classes of cancer mutations including structural rearrangements, copy number alterations, point mutations, and gene expression alterations. A multidisciplinary Sequencing Tumor Board (STB) deliberated on the clinical interpretation of the sequencing results obtained. We tested our sequencing strategy on human prostate cancer xenografts. Next, we enrolled two patients into the clinical protocol and were able to review the results at our STB within 24 days of biopsy. The first patient had metastatic colorectal cancer in which we identified somatic point mutations in NRAS, TP53, AURKA, FAS, and MYH11, plus amplification and overexpression of cyclin-dependent kinase 8 (CDK8). The second patient had malignant melanoma, in which we identified a somatic point mutation in HRAS and a structural rearrangement affecting CDKN2C. The STB identified the CDK8 amplification and Ras mutation as providing a rationale for clinical trials with CDK inhibitors or MEK (mitogenactivated or extracellular signal–regulated protein kinase kinase) and PI3K (phosphatidylinositol 3-kinase) inhibitors, respectively. Integrative high-throughput sequencing of patients with advanced cancer generates a comprehensive, individual mutational landscape to facilitate biomarker-driven clinical trials in oncology.
PMCID: PMC3476478  PMID: 22133722
24.  Coordinated Regulation of Polycomb Group Complexes through microRNAs in Cancer 
Cancer cell  2011;20(2):187-199.
Polycomb Repressive Complexes (PRC1 and PRC2) mediated epigenetic regulation is critical for maintaining cellular homeostasis. Members of Polycomb Group (PcG) proteins including EZH2, a PRC2 component, are up-regulated in various cancer types, implicating their role in tumorigenesis. Here, we have identified several microRNAs (miRNAs) that are repressed by EZH2. These miRNAs in turn regulate the expression of PRC1 proteins, BMI1 and RING2. We found that ectopic overexpression of EZH2-regulated miRNAs attenuated cancer cell growth and invasiveness, and abrogated cancer stem cell properties. Importantly, expression analysis revealed an inverse correlation between miRNA and PRC protein levels in cell culture and prostate cancer tissues. Taken together, our data has uncovered a coordinate regulation of PRC1 and PRC2 activities that is mediated by miRNAs.
PMCID: PMC3157014  PMID: 21840484
25.  TMPRSS2-ERG-mediated feed-forward regulation of wild-type ERG in human prostate cancers 
Cancer Research  2011;71(16):5387-5392.
Recurrent gene fusions involving ETS family genes are a distinguishing feature of human prostate cancers, with TMPRSS2-ERG fusions representing the most common subtype. The TMPRSS2-ERG fusion transcript and its splice variants are well characterized in prostate cancers, however not much is known about the levels and regulation of wild-type ERG. By employing an integrative approach, we demonstrate that the TMPRSS2-ERG gene fusion product binds to the ERG locus and drives the over-expression of wild-type ERG in prostate cancers. Knock-down of TMPRSS2-ERG in VCaP cells resulted in the down regulation of wild-type ERG transcription, while stable over-expression of TMPRSS2-ERG in the gene fusion-negative PC3 cells was associated with the up-regulation of wild-type ERG transcript. Further, androgen signaling-mediated up-regulation of TMPRSS2-ERG resulted in the concomitant up-regulation of wild-type ERG transcription in VCaP cells. The loss of wild-type ERG expression was associated with a decrease in the invasive potential of VCaP cells. Importantly, 38% of clinically localized prostate cancers and 27% of metastatic prostate cancers harboring the TMPRSS2-ERG gene fusions exhibited over-expression of wild-type ERG. Taken together, these results provide novel insights into the regulation of ERG in human prostate cancers.
PMCID: PMC3156376  PMID: 21676887
ERG; prostate cancer; gene fusion

Results 1-25 (44)