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author:("Xu, jinfeng")
2.  Mechanical Stress Triggers Cardiomyocyte Autophagy through Angiotensin II Type 1 Receptor-Mediated p38MAP Kinase Independently of Angiotensin II 
PLoS ONE  2014;9(2):e89629.
Angiotensin II (Ang II) type 1 (AT1) receptor is known to mediate a variety of physiological actions of Ang II including autophagy. However, the role of AT1 receptor in cardiomyocyte autophagy triggered by mechanical stress still remains elusive. The aim of this study was therefore to examine whether and how AT1 receptor participates in cardiomyocyte autophagy induced by mechanical stresses. A 48-hour mechanical stretch and a 4-week transverse aorta constriction (TAC) were imposed to cultured cardiomyocytes of neonatal rats and adult male C57B/L6 mice, respectively, to induce cardiomyocyte hypertrophy prior to the assessment of cardiomyocyte autophagy using LC3b-II. Losartan, an AT1 receptor blocker, but not PD123319, the AT2 inhibitor, was found to significantly reduce mechanical stretch-induced LC3b-II upregulation. Moreover, inhibition of p38MAP kinase attenuated not only mechanical stretch-induced cardiomyocyte hypertrophy but also autophagy. To the contrary, inhibition of ERK and JNK suppressed cardiac hypertrophy but not autophagy. Intriguingly, mechanical stretch-induced autophagy was significantly inhibited by Losartan in the absence of Ang II. Taken together, our results indicate that mechanical stress triggers cardiomyocyte autophagy through AT1 receptor-mediated activation of p38MAP kinase independently of Ang II.
PMCID: PMC3931796  PMID: 24586922
3.  African American Prostate Cancer Survivors’ Treatment Decision-Making and Quality of Life 
To examine African-American prostate cancer (PCa) survivors’ involvement in treatment decision-making (TDM), and examine the association between TDM and quality of life (QOL), using secondary data.
African-American PCa survivors (181) were recruited from the North Carolina Central Cancer Registry. Participants completed a cross-sectional survey that asked about their chosen cancer treatment, TDM factors, and PCa-specific QOL (using the Expanded Prostate Cancer Index – EPIC). Multivariate analysis of covariance was conducted to determine the association between TDM and QOL, controlling for confounders.
Most men reported being active (44.2%) or collaborative (38.1%) in TDM, while 14.4% preferred a passive role. Adjusting for marital status, education and treatment, passive patients reported somewhat better QOL compared to active patients in the following QOL domains: urinary summary (p=.04), urinary function (p=.01), and urinary incontinence (p=.03).
Most African-American PCa survivors preferred to be, and were, actively or collaboratively involved in TDM. However, those who preferred a passive role reported better PCa-specific QOL for the urinary domain compared to others.
Practice Implications
It is important to assess patients’ TDM preference. Patients’ QOL may differ by their TDM role, such that active patients may be more bothered by treatment side effects than other patients.
PMCID: PMC3536017  PMID: 22940374
prostate cancer; quality of life; treatment decision making
4.  A Novel Germline Mutation in HOXB13 Is Associated With Prostate Cancer Risk in Chinese Men 
The Prostate  2012;73(2):169-175.
A rare mutation G84E in HOXB13 was recently identified to be associated with prostate cancer (PCa) in Caucasians. The goal of this study is to test association between HOXB13 genetic variants and PCa risk in Chinese men.
All study subjects were part of the Chinese Consortium for Prostate Cancer Genetics (China PCa). In the first stage, we screened for mutations by sequencing the HOXB13 coding region in 96 unrelated PCa patients. In stage 2, G84E and novel mutations found in stage 1 were genotyped in 671 PCa patients and 1,536 controls. In stage 3, mutation status in 751 additional PCa patients was imputed via haplotype.
The G84E mutation was not detected in this study. However, a novel mutation, G135E, was identified among 96 patients in stage 1. It was also observed twice in 575 additional PCa patients but not in 1,536 control subjects of stage 2. The frequency of G135E was significantly different between cases and controls, with a P-value of 0.027, based on Fisher’s exact test. Haplotype estimation showed that G135E mutation carriers shared a unique haplotype that was not observed in other subjects. In stage 3, two more PCa patients were predicted to carry the G135E mutation.
We identified a novel rare mutation in the HOXB13 gene, G135E, which appears to be a founder mutation. This mutation is associated with increased PCa risk in Chinese men. Consistent with a previous report, our findings provide further evidence that rare mutations in HOXB13 contribute to PCa risk. Prostate 73: 169–175, 2013.
PMCID: PMC3755486  PMID: 22718278
HOXB13; G135E; G84E; prostate cancer; Chinese; rare mutation
5.  A Genome Wide Association Study Identifies Common Variants Associated with Lipid Levels in the Chinese Population 
PLoS ONE  2013;8(12):e82420.
Plasma lipid levels are important risk factors for cardiovascular disease and are influenced by genetic and environmental factors. Recent genome wide association studies (GWAS) have identified several lipid-associated loci, but these loci have been identified primarily in European populations. In order to identify genetic markers for lipid levels in a Chinese population and analyze the heterogeneity between Europeans and Asians, especially Chinese, we performed a meta-analysis of two genome wide association studies on four common lipid traits including total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL) and high-density lipoprotein cholesterol (HDL) in a Han Chinese population totaling 3,451 healthy subjects. Replication was performed in an additional 8,830 subjects of Han Chinese ethnicity. We replicated eight loci associated with lipid levels previously reported in a European population. The loci genome wide significantly associated with TC were near DOCK7, HMGCR and ABO; those genome wide significantly associated with TG were near APOA1/C3/A4/A5 and LPL; those genome wide significantly associated with LDL were near HMGCR, ABO and TOMM40; and those genome wide significantly associated with HDL were near LPL, LIPC and CETP. In addition, an additive genotype score of eight SNPs representing the eight loci that were found to be associated with lipid levels was associated with higher TC, TG and LDL levels (P = 5.52×10-16, 1.38×10-6 and 5.59×10-9, respectively). These findings suggest the cumulative effects of multiple genetic loci on plasma lipid levels. Comparisons with previous GWAS of lipids highlight heterogeneity in allele frequency and in effect size for some loci between Chinese and European populations. The results from our GWAS provided comprehensive and convincing evidence of the genetic determinants of plasma lipid levels in a Chinese population.
PMCID: PMC3875415  PMID: 24386095
6.  Genome-wide association study identifies a new locus JMJD1C at 10q21 that may influence serum androgen levels in men 
Human Molecular Genetics  2012;21(23):5222-5228.
Circulating androgen levels are often used as indicators of physiological or pathological conditions. More than half of the variance for circulating androgen levels is thought to be genetically influenced. A genome-wide association study (GWAS) has identified two loci, SHBG at 17p13 and FAM9B at Xp22, for serum testosterone (T) levels; however, these explain only a small fraction of inter-individual variability. To identify additional genetic determinants of androgen levels, a GWAS of baseline serum T and dihydrotestosterone (DHT) levels was conducted in 3225 men of European ancestry from the REduction by DUtasteride of Prostate Cancer Events (REDUCE) study. Cross-validation was used to confirm the observed associations between the drug (n = 1581) and placebo (n = 1644) groups of REDUCE. In addition to confirming the associations of two known loci with serum T levels (rs727428 in SHBG: P = 1.26 × 10−12; rs5934505 in FAM9B: P = 1.61 × 10−8), we identified a new locus, JMJD1C at 10q21 that was associated with serum T levels at a genome-wide significance level (rs10822184: P = 1.12 × 10−8). We also observed that the SHBG locus was associated with serum DHT levels (rs727428: P = 1.47 × 10−11). Moreover, two additional variants in SHBG [rs72829446, in strong linkage equilibrium with the missense variant D356N (rs6259), and rs1799941] were also independently associated with circulating androgen levels in a statistical scale. These three loci (JMJD1C, SHBG and FAM9B) were estimated to account for ∼5.3 and 4.1% of the variance of serum T and DHT levels. Our findings may provide new insights into the regulation of circulating androgens and potential targets for androgen-based therapy.
PMCID: PMC3607470  PMID: 22936694
7.  Identification of a novel NBN truncating mutation in a family with hereditary prostate cancer 
Familial cancer  2012;11(4):595-600.
Nibrin (NBN), located on chromosome 8q21 is a gene involved in DNA double-strand break repair that has been implicated in the rare autosomal recessive chromosomal instability syndrome known as Nijmegen Breakage Syndrome. NBS is characterized by specific physical characteristics (microcephaly and dysmorphic facies), immunodeficiency, and increased risk of malignancy. Individuals who are heterozygous for NBN mutations are clinically asymptomatic, but may display an elevated risk for certain cancers including, but not limited to, ovarian and prostate cancer as well as various lymphoid malignancies. In this study, 94 unrelated familial prostate cancer cases from the University of Michigan Prostate Cancer Genetics Project (n= 54) and Johns Hopkins University (n=40) were subjected to targeted next-generation sequencing of the exons, including UTRs, of NBN. One individual of European descent, diagnosed with prostate cancer at age 52, was identified to have a heterozygous 2117 C>G mutation in exon 14 of the gene, that results in a premature stop at codon 706 (S706X). Sequencing of germline DNA from additional male relatives showed partial co-segregation of the NBN S706X mutation with prostate cancer. This NBN mutation was not observed among 2768 unrelated European men (1859 with prostate cancer and 909 controls). NBN is involved in double-strand break repair as a component of the MRE11 (meiotic recombination 11)/RAD50/NBN genomic stability complex. The S706X mutation truncates the protein in a highly conserved region of NBN near the MRE11 binding site, thus suggesting a role for rare NBN mutations in prostate cancer susceptibility.
PMCID: PMC3485445  PMID: 22864661
Cancer; Hereditary; Prostate; NBN gene
8.  Potential Impact of Adding Genetic Markers to Clinical Parameters in Predicting Prostate Biopsy Outcomes in Men Following an Initial Negative Biopsy: Findings from the REDUCE Trial 
European urology  2012;62(6):953-961.
Several germline single nucleotide polymorphisms (SNPs) have been consistently associated with prostate cancer (PCa) risk.
To determine whether there is an improvement in PCa risk prediction by adding these SNPs to existing predictors of PCa.
Design, setting, and participants
Subjects included men in the placebo arm of the randomized Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial in whom germline DNA was available. All men had an initial negative prostate biopsy and underwent study-mandated biopsies at 2 yr and 4 yr. Predictive performance of baseline clinical parameters and/or a genetic score based on 33 established PCa risk-associated SNPs was evaluated.
Outcome measurements and statistical analysis
Area under the receiver operating characteristic curves (AUC) were used to compare different models with different predictors. Net reclassification improvement (NRI) and decision curve analysis (DCA) were used to assess changes in risk prediction by adding genetic markers.
Results and limitations
Among 1654 men, genetic score was a significant predictor of positive biopsy, even after adjusting for known clinical variables and family history (p = 3.41 × 10−8). The AUC for the genetic score exceeded that of any other PCa predictor at 0.59. Adding the genetic score to the best clinical model improved the AUC from 0.62 to 0.66 (p < 0.001), reclassified PCa risk in 33% of men (NRI: 0.10; p = 0.002), resulted in higher net benefit from DCA, and decreased the number of biopsies needed to detect the same number of PCa instances. The benefit of adding the genetic score was greatest among men at intermediate risk (25th percentile to 75th percentile). Similar results were found for high-grade (Gleason score ≥7) PCa. A major limitation of this study was its focus on white patients only.
Adding genetic markers to current clinical parameters may improve PCa risk prediction. The improvement is modest but may be helpful for better determining the need for repeat prostate biopsy. The clinical impact of these results requires further study.
PMCID: PMC3568765  PMID: 22652152
Prostate cancer; Genetics; AUC; Detection rate; Reclassification; SNPs; Prospective study; Clinical trial
9.  RTK/ERK Pathway under Natural Selection Associated with Prostate Cancer 
PLoS ONE  2013;8(11):e78254.
Prostate cancer (PCa) is a global disease causing large numbers of deaths every year. Recent studies have indicated the RTK/ERK pathway might be a key pathway in the development of PCa. However, the exact association and evolution-based mechanism remain unclear. This study was conducted by combining genotypic and phenotypic data from the Chinese Consortium for Prostate Cancer Genetics (ChinaPCa) with related databases such as the HapMap Project and Genevar. In this analysis, expression of quantitative trait loci (eQTLs) analysis, natural selection and gene-based pathway analysis were involved. The pathway analysis confirmed the positive relationship between PCa risk and several key genes. In addition, combined with the natural selection, it seems that 4 genes (EGFR, ERBB2, PTK2, and RAF1) with five SNPs (rs11238349, rs17172438, rs984654, rs11773818, and rs17172432) especially rs17172432, might be pivotal factors in the development of PCa. The results indicate that the RTK/ERK pathway under natural selection is a key link in PCa risk. The joint effect of the genes and loci with positive selection might be one reason for the development of PCa. Dealing with all the factors simultaneously might give insight into prevention and aid in predicting the success of potential therapies for PCa.
PMCID: PMC3817240  PMID: 24223781
10.  A Comparison of Bayesian and Frequentist Approaches to Incorporating External Information for the Prediction of Prostate Cancer Risk 
Genetic epidemiology  2012;36(1):71-83.
We present the most comprehensive comparison to date of the predictive benefit of genetics in addition to currently used clinical variables, using genotype data for 33 single-nucleotide polymorphisms (SNPs) in 1,547 Caucasian men from the placebo arm of the REduction by DUtasteride of prostate Cancer Events (REDUCE®) trial. Moreover, we conducted a detailed comparison of three techniques for incorporating genetics into clinical risk prediction. The first method was a standard logistic regression model, which included separate terms for the clinical covariates and for each of the genetic markers. This approach ignores a substantial amount of external information concerning effect sizes for these Genome Wide Association Study (GWAS)-replicated SNPs. The second and third methods investigated two possible approaches to incorporating meta-analysed external SNP effect estimates – one via a weighted PCa ‘risk’ score based solely on the meta analysis estimates, and the other incorporating both the current and prior data via informative priors in a Bayesian logistic regression model. All methods demonstrated a slight improvement in predictive performance upon incorporation of genetics. The two methods that incorporated external information showed the greatest receiver-operating-characteristic AUCs increase from 0.61 to 0.64. The value of our methods comparison is likely to lie in observations of performance similarities, rather than difference, between three approaches of very different resource requirements. The two methods that included external information performed best, but only marginally despite substantial differences in complexity.
PMCID: PMC3791431  PMID: 22890972
prostate cancer; genetic clinical risk prediction; genetic scores; Bayesian logistic regression; predictive assessment
11.  Variation in IL10 and Other Genes Involved in the Immune Response and in Oxidation and Prostate Cancer Recurrence 
To evaluate the association of variation in genes involved in immune response, including IL10, production and detoxification of reactive oxygen species, and repair of oxidative DNA damage with risk of recurrence after surgery for localized prostate cancer.
We conducted a nested case-control study of men who had a radical prostatectomy in 1993–2001. 484 recurrence cases and 484 controls were matched on age, race, and pathologic stage and grade. Germline DNA was extracted from paraffin-embedded unaffected lymph nodes. We genotyped candidate single nucleotide polymorphisms (SNPs) in IL10, CRP, GPX1, GSR, GSTP1, hOGG1, IL1B, IL1RN, IL6, IL8, MPO, NOS2, NOS3, SOD1, SOD2, SOD3, TLR4, and TNF and tagging SNPs in IL10, CRP, GSR, IL1RN, IL6, NOS2, and NOS3. We used conditional logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI).
The minor allele (A) in IL10 rs1800872, known to produce less interleukin-10, was associated with a higher risk of recurrence (OR=1.76, 95% CI: 1.00–3.10), and the minor allele (G) in rs1800896, known to produce more interleukin-10, was associated with a lower risk of recurrence (OR=0.66, 95% CI: 0.48–0.91). We also observed associations for candidate SNPs in CRP, GSTP1, and IL1B. A common IL10 haplotype and two common NOS2 haplotypes were associated with recurrence.
Variation in IL10, CRP, GSTP1, IL1B, and NOS2 was associated with recurrence independent of pathologic prognostic factors.
This study supports that genetic variation in immune response and oxidation influence recurrence risk and suggests genetic variation in these pathways may inform prognosis.
PMCID: PMC3467312  PMID: 22859398
genotype; prostate; cancer; recurrence; risk
12.  Comparison of the characteristics of mesenchymal stem cells obtained from prostate tumors and from bone marrow cultured in conditioned medium 
Prostate cancer (PCa) is the most common type of cancer worldwide. Mesenchymal stem cells (MSCs) can also be utilized as ‘tumor stromal cells’, which are associated with invasive and metastatic malignant tumor cells. Our study aimed to investigate MSCs in prostate tumors and normal MSCs and evaluate their differential characteristics. Normal MSCs (BMMSCs) were isolated from the femur and tibia of normal mice; prostate tumor MSCs (PCa-MSCs) were obtained from prostate tumors implanted in mice. These two types of MSCs were induced to differentiate into adipocytes, bone cells and chondrocytes. Growth curves were used to analyze the growth ability of PCa-MSCs and BMMSCs. Tritium-labeled thymidine (3H-TdR) was used to evaluate cell proliferation of RM-1 stimulated by MSCs. The time taken for PCa-MSCs to reach 90% confluence was markedly shorter than that of BMMSCs (8–10 vs. 12–14 days). The differentiation ability of PCa-MSCs was similar to that described in previous reports. The growth ability of PCa-MSCs was significantly higher than that of BMMSCs. The proliferative activity of PCa-MSCs was also higher than that of BMMSCs. Our data showed that PCa-MSCs exhibit identical characteristics when compared with those of MSCs. Additionally, their proliferative activity and growth ability were significantly higher when compared with these values in BMMSCs, which appear to have an intrinsic, cell-specific capacity to localize to PCa. The possible role of PCa-MSCs in the process of PCa development requires further clarification.
PMCID: PMC3501413  PMID: 23170131
prostate cancer; mesenchymal stem cells; RM-1
13.  Adipocyte NCoR Knockout Decreases PPARγ Phosphorylation and Enhances PPARγ Activity and Insulin Sensitivity 
Cell  2011;147(4):815-826.
Insulin resistance, tissue inflammation and adipose tissue dysfunction are features of obesity/Type 2 diabetes. Accordingly, we generated adipocyte-specific Nuclear Receptor Corepressor (NCoR) knock-out (AKO) mice to investigate the function of NCoR in adipocyte biology and glucose/insulin homeostasis. Despite increased obesity, glucose tolerance was improved in AKO mice, and euglycemic clamp studies demonstrated enhanced insulin sensitivity in liver, muscle and fat. Adipose tissue macrophage infiltration and inflammation were also decreased. PPARγ response genes were upregulated in adipose tissue from AKO mice and CDK5-mediated PPARγ ser-273 phosphorylation was reduced, creating a constitutively active PPARγ state. This identifies a novel function of NCoR as an adaptor protein which enhances the ability of CDK5 to associate with and phosphorylate PPARγ. The dominant function of adipocyte NCoR is to transrepress PPARγ and promote PPARγ ser-273 phosphorylation, such that NCoR deletion leads to adipogenesis, reduced inflammation, and enhanced systemic insulin sensitivity, phenocopying the TZD treated state.
PMCID: PMC3783197  PMID: 22078880
nuclear corepressor; insulin resistance; obesity; macrophage; adipogenesis
14.  Germline Mutations in HOXB13 and Prostate-Cancer Risk 
The New England journal of medicine  2012;366(2):141-149.
Family history is a significant risk factor for prostate cancer, although the molecular basis for this association is poorly understood. Linkage studies have implicated chromosome 17q21-22 as a possible location of a prostate-cancer susceptibility gene.
We screened more than 200 genes in the 17q21-22 region by sequencing germline DNA from 94 unrelated patients with prostate cancer from families selected for linkage to the candidate region. We tested family members, additional case subjects, and control subjects to characterize the frequency of the identified mutations.
Probands from four families were discovered to have a rare but recurrent mutation (G84E) in HOXB13 (rs138213197), a homeobox transcription factor gene that is important in prostate development. All 18 men with prostate cancer and available DNA in these four families carried the mutation. The carrier rate of the G84E mutation was increased by a factor of approximately 20 in 5083 unrelated subjects of European descent who had prostate cancer, with the mutation found in 72 subjects (1.4%), as compared with 1 in 1401 control subjects (0.1%) (P = 8.5×10−7). The mutation was significantly more common in men with early-onset, familial prostate cancer (3.1%) than in those with late-onset, nonfamilial prostate cancer (0.6%) (P = 2.0×10−6).
The novel HOXB13 G84E variant is associated with a significantly increased risk of hereditary prostate cancer. Although the variant accounts for a small fraction of all prostate cancers, this finding has implications for prostate-cancer risk assessment and may provide new mechanistic insights into this common cancer. (Funded by the National Institutes of Health and others.)
PMCID: PMC3779870  PMID: 22236224
16.  Mitochondrial Distribution of Neuroglobin and Its Response to Oxygen-Glucose Deprivation in Primary Cultured Mouse Cortical Neurons 
Neuroscience  2012;218:235-242.
Neuroglobin (Ngb) is a new member of the globin family and a novel endogenous neuroprotective molecule, but its neuroprotective mechanisms remain largely undefined. Previous studies suggest Ngb is both physically and functionally related to mitochondria, however without direct evidence. Our recent discovery has shown that Ngb can physically interact with a number of mitochondrial proteins. In this study we aimed to define the physical interaction between Ngb and mitochondria by determining whether there is a mitochondrial distribution of Ngb under both physiological resting and pathological oxygen-glucose deprivation (OGD) conditions. Western blot for the first time revealed a small portion of Ngb was physically localized in mitochondria, and the relative mitochondrial Ngb level was significantly increased after OGD in primary cultured mouse cortical neurons, indicating a translocation of Ngb into mitochondria. Complementary approaches including confocal imaging and immuno-electron microscopy confirmed Ngb distribution in mitochondria under both basal resting condition and OGD. Inhibitors of mitochondria permeability transition pore (mPTP) and Voltage Dependent Anion Channel (VDAC) blocked OGD-induced increase of mitochondrial Ngb level, demonstrating a possible role of mPTP in Ngb’s mitochondrial translocation. We further found that Ngb overexpression-conferred neuroprotection was correlated with increased mitochondrial Ngb level, suggesting the mitochondria distribution of Ngb is clearly associated with and even might contribute to Ngb’s neuroprotection.
PMCID: PMC3394186  PMID: 22659017
17.  Genetic variation in the upstream region of ERG and prostate cancer 
Cancer causes & control : CCC  2009;20(7):1173-1180.
A considerable fraction of prostate cancers harbor a gene fusion between the androgen-regulated TMPRSS2 and ERG, one of the most frequently over-expressed proto-oncogenes in prostate cancer. Here, we investigated if inherited genetic variation upstream of ERG alters prostate cancer risk and survival.
We genotyped 21 haplotype tagging SNPs (htSNPs) covering 123 kb of 5′UTR DNA including exon 3 of ERG in 2,760 incident prostate cancer cases and 1,647 controls from a population-based Swedish case–control study (CAPS). Individual SNPs and haplotypes were tested for association with prostate cancer risk and survival.
One haplotype—′CTCGTATG′ located 100 kb upstream of ERG—was associated with lethal prostate cancer (HR, 1.36; 95% CI, 1.2–1.9, p = 0.006). Carriers of the variant ‘T’ allele of rs2836626 were diagnosed with higher TNM-stage (p = 0.009) and had an increased risk of prostate cancer-specific death (HR = 1.3; 95% CI, 1.1–1.7, p = 0.009). However, this association did not remain statistically significant after adjusting for multiple testing. We found overall no association between ERG variation and prostate cancer risk.
Genetic variation upstream of ERG may alter prostate cancer stage and ultimately prostate cancer-specific death but it is unlikely that it plays a role in prostate cancer development.
PMCID: PMC3755494  PMID: 19205910
Prostate cancer; ERG; Haplotype; Polymorphism; Survival
18.  Utility of Genome-Wide Association Study findings: prostate cancer as a translational research paradigm 
Journal of internal medicine  2012;271(4):344-352.
Genomewide Association Studies (GWAS) have identified thousands of consistently replicated associations between genetic markers and complex disease risk, including cancers. Alone, these markers have limited utility in risk prediction; however, when several of these markers are used in combination, the predictive performance appears to be similar to currently many available clinical predictors. Despite this, there are divergent views regarding the clinical validity and utility of these genetic markers in risk prediction. There are valid concerns, thus providing a direction for new lines of research. Herein, we outline the debate, and use the example of prostate cancer to highlight emerging evidence from studies that aim to address potential concerns. We also describe a translational framework which could be used to guide the development of a new generation of comprehensive research studies aimed at capitalizing on these exciting new discoveries.
PMCID: PMC3753782  PMID: 22272820
cancer; gene polymorphism; molecular medicine; risk factors
19.  GPR105 ablation prevents inflammation and improves insulin sensitivity in mice with diet-induced obesity 
GPR105, a G-protein coupled receptor for UDP-glucose, is highly expressed in several human tissues and participates in the innate immune response. Since inflammation has been implicated as a key initial trigger for type 2 diabetes, we hypothesized that GPR105 (official gene name: P2RY14) might play a role in the initiation of inflammation and insulin resistance in obesity. To this end, we investigated glucose metabolism in GPR105 knockout (KO) and wild-type (WT) mice fed a high-fat diet (HFD). We also examined whether GPR105 regulates macrophage recruitment to liver or adipose tissues by in vivo monocyte tracking and in vitro chemotaxis experiments, followed by transplantation of bone marrow from either KO or WT donors to WT recipients. Our data show that genetic deletion of GPR105 confers protection against HFD-induced insulin resistance, with reduced macrophage infiltration and inflammation in liver, and increased insulin-stimulated Akt phosphorylation in liver, muscle and adipose tissue. By tracking monocytes from either KO or WT donors, we found that fewer KO monocytes were recruited to the liver of WT recipients. Furthermore, we observed that UDP-Glc enhanced the in vitro migration of bone marrow-derived macrophages from WT but not KO mice, and that plasma UDP-Glc levels were significantly higher in obese versus lean mice. Finally, we confirmed that insulin sensitivity improved in HFD mice with a myeloid cell-specific deletion of GPR105. These studies indicate that GPR105 ablation mitigates HFD-induced insulin resistance by inhibiting macrophage recruitment and tissue inflammation. Hence, GPR105 provides a novel link between innate immunity and metabolism.
PMCID: PMC3411902  PMID: 22778393
20.  Using graded response model for the prediction of prostate cancer risk 
Human genetics  2012;131(8):1327-1336.
Disease risk-associated single nucleotide polymorphisms (SNPs) identified from genome-wide association studies (GWAS) have the potential to be used for disease risk prediction. An important feature of these risk-associated SNPs is their weak individual effect but stronger cumulative effect on disease risk. To date, a stable summary estimate of the joint effect of genetic variants on disease risk prediction is not available. In this study, we propose to use the graded response model (GRM), which is based on the item response theory, for estimating the individual risk that is associated with a set of SNPs. We compare the GRM with a recently proposed risk prediction model called cumulative relative risk (CRR). Thirty-three prostate cancer risk-associated SNPs were originally discovered in GWAS by December 2009. These SNPs were used to evaluate the performance of GRM and CRR for predicting prostate cancer risk in three GWAS populations, including populations from Sweden, Johns Hopkins Hospital, and the National Cancer Institute Cancer Genetic Markers of Susceptibility study. Computational results show that the risk prediction estimates of GRM, compared to CRR, are less biased and more stable.
PMCID: PMC3734950  PMID: 22461065
21.  Association of a Common Variant at 10q26 and Benign Prostatic Hyperplasia Aggressiveness in Han Chinese Descent 
Recent studies reported that rs2252004 at 10q26 was significantly associated with prostate cancer (PCa) risk in a Japanese population and was subsequently confirmed in a Chinese population. We aimed to assess the relationship between this locus and risk/aggressiveness of benign prostatic hyperplasia (BPH). The current study included 426 BPH cases and 1,008 controls from Xinhua Hospital in Shanghai, China. All BPH patients were treated with α-adrenergic blockers and 5α-reductase inhibitors for at least 9 months. Associations between rs2252004 and BPH risk/aggressiveness were tested using logistic regression. Associations between rs2252004 and clinical parameters including International Prostate Symptom Score (IPSS), total prostate volume (TPV), total PSA (tPSA), and free PSA (fPSA) were evaluated by linear regression. Allele “A” in rs2252004 was significantly associated with increased risk for aggressiveness of BPH in a Chinese population (OR = 1.42, 95% CI: 1.04–1.96, P = 0.03). Patients with the genotype “A/A” (homozygous minor allele) had an increase of IPSS and TPV after treatment (P = 0.045 and 0.024, resp.). No association was observed between rs2252004, BPH risk, and baseline clinicopathological traits (All P > 0.05). Our study is the first to show that rs2252004 at 10q26 was associated with BPH aggressiveness and efficacy of BPH treatment.
PMCID: PMC3747368  PMID: 23984071
22.  Evaluation of PPP2R2A as a prostate cancer susceptibility gene: comprehensive germline and somatic study 
Cancer genetics  2011;204(7):375-381.
PPP2R2A, mapped to 8p21.2, encodes for the α isoform of the regulatory B55 subfamily of the protein phosphatase 2 (PP2A). PP2A is one of the four major Ser/Thr phosphatases and is implicated in the negative control of cell growth and division. Because of its known functions and location within a chromosomal region where evidence for linkage and somatic loss of heterozygosity was found, we hypothesized that either somatic copy number changes or germline sequence variants in PPP2R2A may increase prostate cancer (PCa) risk. We examined PPP2R2A deletion status in 141 PCa samples using Affymetrix SNP arrays. It was found that PPP2R2A was commonly (67.1%) deleted in tumor samples including a homozygous deletion in 3 tumors (2.1%). We performed a mutation screen for PPP2R2A in 96 probands of hereditary prostate cancer (HPC) families. No high risk mutations were identified. Additionally, we reanalyzed 10 SNPs of PPP2R2A in sporadic PCa cases and controls. No significant differences in the allele and genotype frequencies were observed among either PCa cases and controls or PCa aggressive and non-aggressive cases. Taken together, these results suggest that a somatic deletion rather than germline sequence variants of PPP2R2A may play a more important role in PCa susceptibility.
PMCID: PMC3722858  PMID: 21872824
PPP2R2A; homozygous deletion; prostate cancer
23.  DNA methylation alterations exhibit intra-individual stability and inter-individual heterogeneity in prostate cancer metastases 
Science translational medicine  2013;5(169):169ra10.
Human cancers nearly ubiquitously harbor epigenetic alterations. While such alterations in epigenetic marks, including DNA methylation, are potentially heritable, they can also be dynamically altered. Given this potential for plasticity, the degree to which epigenetic changes can be subject to selection and act as drivers of neoplasia has been questioned. Here, we carried out genome-scale analyses of DNA methylation alterations in lethal metastatic prostate cancer and created DNA methylation “cityscape” plots to visualize these complex data. We show that somatic DNA methylation alterations, despite showing marked inter-individual heterogeneity among men with lethal metastatic prostate cancer, were maintained across all metastases within the same individual. The overall extent of maintenance in DNA methylation changes was comparable to that of genetic copy number alterations. Regions that were frequently hypermethylated across individuals were markedly enriched for cancer and development/differentiation related genes. Additionally, regions exhibiting high consistency of hypermethylation across metastases within individuals, even if variably hypermethylated across individuals, showed enrichment of cancer-related genes. Interestingly, whereas some regions showed intra-individual metastatic tumor heterogeneity in promoter methylation, such methylation alterations were generally not correlated with gene expression. This was despite a general tendency for promoter methylation patterns to be strongly correlated with gene expression, particularly at regions that were variably methylated across individuals. These findings suggest that DNA methylation alterations have the potential for producing selectable driver events in carcinogenesis and disease progression and highlight the possibility of targeting such epigenome alterations for development of longitudinal markers and therapeutic strategies.
PMCID: PMC3577373  PMID: 23345608
24.  Age-Specific Prostate Specific Antigen Cutoffs for Guiding Biopsy Decision in Chinese Population 
PLoS ONE  2013;8(6):e67585.
Age-specific prostate specific antigen (PSA) cutoffs for prostate biopsy have been widely used in the USA and European countries. However, the application of age-specific PSA remains poorly understood in China.
Between 2003 and 2012, 1,848 men over the age of 40, underwent prostate biopsy for prostate cancer (PCa) at Huashan Hospital, Shanghai, China. Clinical information and blood samples were collected prior to biopsy for each patient. Men were divided into three age groups (≤60, 61 to 80, and >80) for analyses. Digital rectal examination (DRE), transrectal ultrasound (prostate volume and nodule), total PSA (tPSA), and free PSA (fPSA) were also included in the analyses. Logistic regression was used to build the multi-variate model.
Serum tPSA levels were age-dependent (P = 0.008), while %fPSA (P = 0.051) and PSAD (P = 0.284) were age-independent. At a specificity of 80%, the sensitivities for predicting PCa were 83%, 71% and 68% with tPSA cutoff values of 19.0 ng/mL (age≤60),21.0 ng/mL (age 61–80), and 23.0 ng/mL (age≥81). Also, sensitivities at the same tPSA levels were able to reach relatively high levels (70%–88%) for predicting high-grade PCa. Area (AUC) under the receive operating curves (ROCs) of tPSA, %fPSA, PSAD and multi-variate model were different in age groups. When predicting PCa, the AUC of tPSA, %fPSA, PSAD and multi-variate model were 0.90, 0.57, 0.93 and 0.87 respectively in men ≤60 yr; 0.82, 0.70, 0.88 and 0.86 respectively in men 61–80 yr; 0.79, 0.78, 0.87 and 0.88 respectively in men>80 yr. When predicting Gleason Score ≥7 or 8 PCa, there were no significant differences between AUCs of each variable.
Age-specific PSA cutoff values for prostate biopsy should be considered in the Chinese population. Indications for prostate biopsies (tPSA, %fPSA and PSAD) should be considered based on age in the Chinese population.
PMCID: PMC3692456  PMID: 23825670
25.  Suppression of Tak1 Promotes Prostate Tumorigenesis 
Cancer research  2012;72(11):2833-2843.
Over 30% of primary prostate cancers contain a consensus deletion of an approximately 800 kb locus on chromosome 6q15.1. The MAP3K7 gene, which encodes TGF-β Activated Kinase-1 (Tak1), is a putative prostate tumor suppressor gene within this region whose precise function remains obscure. In this study, we investigated the role of Tak1 in human and murine prostate cancers. In 50 well-characterized human cancer specimens, we found that Tak1 expression was progressively lost with increasing Gleason grade, both within each cancer and across all cancers. In murine prostate stem cells and Tak1-deficient prostatic epithelial cells, Tak1 loss increased proliferation, migration, and invasion. When prostate stem cells attenuated for Tak1 were engrafted with fetal urogenital mesenchyme, the histopathology of the grafts reflected the natural history of prostate cancer leading from prostatic intraepithelial neoplasia to invasive carcinoma. In the grafts containing Tak1-suppressed prostate stem cells, p38 and JNK activity was attenuated and proliferation was increased. Together, our findings functionally validate the proposed tumor suppressor role of Tak1 in prostate cancer.
PMCID: PMC3654674  PMID: 22467172
Tak1; Prostate cancer; Tumor suppressor; Tissue recombination; TGF-β

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