The appearance of a mutant androgen receptor, F876L-AR, in prostate cancer cells chronically exposed to enzalutamide or ARN-509 promotes a switch from antagonist to agonist receptor function, undermining the potential long term effectiveness of these second generation anti-androgen drugs.
The Translational Research Working Group (TRWG) was created as a national initiative to evaluate the current status of the National Cancer Institute’s investment in translational research and envision its future. The TRWG conceptualized translational research as a set of six developmental processes or pathways focused on various clinical goals. One of those pathways describes the development of agents—both small molecules and biologics—for the treatment and prevention of cancer. The Agents Developmental Pathway was conceived not as a comprehensive description of the corresponding real-world processes, but rather as a tool designed to facilitate movement of an agent through the translational process to the point where it can begin definitive clinical testing. This article presents the Agents Developmental Pathway and discusses key challenges associated with the processes described.
Sex steroid hormone concentrations and insulin-like growth factor (IGF) proteins have been independently associated with risk of cancer, chronic diseases, and mortality. However, studies that evaluated the inter-relation between the sex hormones and IGF pathways have provided mixed results. We examined the association between endogenous sex hormones and sex hormone-binding globulin (SHBG) with IGF-1 and IGF-binding protein 3 (IGFBP-3) in a population-based sample of US men.
Data from 1,135 men aged 20 years or older participating in the third National Health and Nutrition Examination Survey (NHANES III) were analyzed. Weighted linear regression was used to estimate geometric means and 95 % confidence intervals for IGF-1 and IGFBP-3 concentrations by sex steroid hormones and SHBG after adjusting for age, race/ethnicity, body mass index, waist circumference, alcohol consumption, cigarette smoking, physical activity, diabetes, and mutually adjusting for other sex hormones and SHBG.
No significant association was observed between sex steroid hormones, SHBG, and IGF-1 concentrations. Total estradiol (% difference in Q5 − Q1 geometric means −9.7 %; P-trend 0.05) and SHBG (% difference −7.3 %; P-trend 0.02) were modestly inversely associated with IGFBP-3. Total testosterone was modestly inversely associated with IGFBP-3 (% difference −6.2 %; P-trend 0.01), but this association disappeared after adjustment for total estradiol and SHBG (% difference 2.6 %; P-trend 0.23). Androstanediol glucuronide was not associated with IG-FBP-3.
These findings suggest that there may be inter-relationships between circulating total estradiol, SHBG, and IGFBP-3 concentrations. Future research may consider these inter-relationships when evaluating potential joint effects of the sex hormones and IGF pathways.
Testosterone; Estradiol; Sex hormone-binding globulin (SHBG); Insulin growth factor-1 (IGF-1); Insulin growth factor-binding protein 3 (IGFBP-3)
Men with a negative first prostate biopsy will undergo one or more additional biopsies if they remain at high suspicion of prostate cancer. To date, there are no diagnostic tests capable of identifying patients at risk for a positive diagnosis with the predictive power needed to eliminate unnecessary repeat biopsies. Efforts to develop clinical tests using the epigenetic signature of cores recovered from first biopsies have been limited to a few markers and lack the sensitivity and specificity needed for widespread clinical adoption.
We developed methylation-specific quantitative polymerase chain reaction assays for a panel of 24 markers that are preferentially methylated in prostate cancer. We modified the bisulfite conversion conditions to allow the integration of the methylation information from multiple markers. We determined the methylation status of the 24 markers in 213 prostate biopsy cores from 104 patients, 37 prostate cancer patients and 67 controls. We performed logistic regression on combinations of markers as well as the entire panel of 24 markers to identify the best candidates for a diagnostic test.
The marker panel differentiated between cancer cores and benign cores from non-cancer patients with 100% sensitivity and 97% specificity. Furthermore, the panel detected significant methylation in benign cores from prostate cancer patients that was not present in controls. Using methylation of 5 out of 24 to define a cancer case, the analysis of a single benign biopsy core identified 62% of prostate cancer patients undergoing repeat biopsies. ROC curve analysis showed that markers commonly methylated in benign cores from cancer patients are the best candidates for a diagnostic test. The results suggest that 5 to 10 markers will be needed to achieve optimal predictive power.
This study shows that epigenetic field effects differ significantly between cancer patients and controls. Their detection in benign biopsy cores can form the basis of diagnostic tests to identify patients in need of repeat biopsies, reducing the cost of continued PCA screening by up to 40%. They could also be used to identify prostate cancer patients with low grade disease who are likely candidates for active surveillance or focal therapy.
Electronic supplementary material
The online version of this article (doi:10.1186/s40364-014-0025-9) contains supplementary material, which is available to authorized users.
DNA methylation; Prostate cancer; Repeat biopsies; High grade prostatic intraepithelial lesions; Atypical small acinar proliferation; Early cancer diagnostics
Sex steroid hormones and inflammatory biomarkers are both associated with the development and progression of chronic diseases, but their interrelationship is relatively uncharacterized. We examined the association of sex hormones and sex hormone binding globulin (SHBG) with biomarkers of inflammation, C-reactive protein (CRP) and white blood cell (WBC) count. The study included data from 809 adult men in the National Health and Nutrition Examination Survey 1999–2004. Geometric means and 95% confidence intervals were estimated separately for CRP and WBC concentrations by sex steroid hormones and SHBG using weighted linear regression models. Higher concentrations of total (slope per 1 quintile in concentration, −0.18; P-trend, 0.001) and calculated free (slope, −0.13; P-trend, 0.03) testosterone were statistically significantly associated with lower concentrations of CRP, but not with WBC count. Men in the bottom quintile of total testosterone (≤3.3 ng/mL), who might be considered to have clinically low testosterone, were more likely to have elevated CRP (≥ 3 mg/L) compared to men in the top four quintiles (OR, 1.61; 95% CI, 1.00 – 2.61). Total and calculated free estradiol (E2) were positively associated with both CRP (Total E2: slope, 0.14; P-trend, <0.001; Free E2: slope, 0.15; P-trend, <0.001) and WBC (Total E2: slope, 0.02; P-trend, 0.08; Free E2: slope, 0.02; P-trend, 0.02) concentrations. SHBG concentrations were inversely associated with WBC count (slope, −0.03; P-trend, 0.04), but not with CRP. These cross-sectional findings are consistent with the hypothesis that higher androgen and lower estrogen concentrations may have an anti-inflammatory effect in men.
testosterone; estradiol; C-reactive protein; white blood cell; cross-sectional study
Alterations in methylation of CpG dinucleotides at the 5 position of deoxycytidine residues (5mC) are a hallmark of cancer cells, including testicular germ cell tumors. Virtually all testicular germ cell tumors are believed to be derived from intratubular germ cell neoplasia unclassified (IGCNU), which is thought to arise from primordial germ cells. Prior studies revealed that seminomas contain reduced levels of global DNA methylation as compared with nonseminomatous germ cell tumors. Smiraglia et al have proposed a model whereby seminomas arise from IGCNU cells derived from primordial germ cells that have undergone 5mC erasure, and nonseminomas arise from IGCNU cells derived from primordial germ cells that have already undergone de novo methylation after the original erasure of methylation and contain normal 5mC levels. Yet the methylation status of IGCNU has not been determined previously. We used immunohistochemical staining against 5mC to evaluate global methylation in IGCNU and associated invasive testicular germ cell tumors. Strikingly, staining for 5mC was undetectable (or markedly reduced) in the majority of IGCNU and seminomas, yet there was robust staining in nonseminomatous germ cell tumors. The lack of staining for 5mC in IGCNU and seminomas was also found in mixed germ cell tumors containing both seminomatous and nonseminomatous components. Lack of 5mC staining was not related to a lack of the maintenance methyltransferase (DNA methyltransferase 1) protein. We conclude that testicular germ cell tumors are derived in most cases from IGCNU cells that have undergone developmentally programmed 5mC erasure and that the degree of subsequent de novo methylation is most closely related to the differentiation state of the neoplastic cells. That is, IGCNU cells and seminoma cells remain unmethylated, whereas all other histological types appear to arise after de novo methylation.
seminoma; nonseminomatous germ cell tumors; IGCNU; global methylation
Granulocyte-macrophage colony-stimulating factor (GM-CSF) gene-transduced, irradiated tumor vaccines induce potent, T-cell-mediated antitumor immune responses in preclinical models. We report the initial results of a Phase I trial evaluating this strategy for safety and the induction of immune responses in patients with metastatic renal cell carcinoma (RCC). Patients were treated in a randomized, double-blind dose-escalation study with equivalent doses of autologous, irradiated RCC vaccine cells with or without ex vivo human GM-CSF gene transfer. The replication-defective retroviral vector MFG was used for GM-CSF gene transfer. No dose-limiting toxicities were encountered in 16 fully evaluable patients. GM-CSF gene-transduced vaccines were equivalent in toxicity to nontransduced vaccines up to the feasible limits of autologous tumor vaccine yield. No evidence of autoimmune disease was observed. Biopsies of intradermal sites of injection with GM-CSF gene-transduced vaccines contained distinctive macrophage, dendritic cell, eosinophil, neutrophil, and T-cell infiltrates similar to those observed in preclinical models of efficacy. Histological analysis of delayed-type hypersensitivity responses in patients vaccinated with GM-CSF-transduced vaccines demonstrated an intense eosinophil infiltrate that was not observed in patients who received nontransduced vaccines. An objective partial response was observed in a patient treated with GM-CSF gene-transduced vaccine who displayed the largest delayed-type hypersensitivity conversion. No replication-competent retrovirus was detected in vaccinated patients. This Phase I study demonstrated the feasibility, safety, and bioactivity of an autologous GM-CSF gene-transduced tumor vaccine for RCC patients.
Modifications to DNA and histone tails represent key epigenetic marks involved in establishing and maintaining cell identity and can be dysregulated in human diseases, including cancer. Two such modifications, tri-methylation of lysine-27 on histone H3 (H3K27me3) mediated by the Polycomb complex and hydroxymethylation of cytosines on DNA, have recently been shown to be dynamically regulated during differentiation. Here, we show that global levels of 5-hydroxymethylcytosine (5hmC) and H3K27me3 are highly correlated across a variety of somatic tissues. In multiple hierarchically organized tissues, both marks showed almost identical cell-by-cell distribution patterns that exhibited a tight association with differentiation. In particular, tissue stem cell compartments were characterized by low levels of both marks, whereas differentiated cell compartments exhibited high levels of 5hmC and H3K27me3. This pattern of correlation between the two marks could be recapitulated in an in vitro model system of induced differentiation in prostate epithelial cells. While the correlation between 5hmC and H3K27me3 levels is also maintained in human cancers, the degree of correlation is reduced. These findings suggest a previously unappreciated link between 5hmC and H3K27me3 regulation that should be explored in future mechanistic studies.
5-hydroxymethylcytosine; DNA methylation; differentiation; cancer; H3K27me3; polycomb; epigenetics
TMPRSS2-ERG rearrangements occur in approximately 50% of prostate cancers and therefore represent one of the most frequently observed structural rearrangements in all cancers. However, little is known about the genomic architecture of such rearrangements. We therefore designed and optimized a pipeline involving target-capture of TMPRSS2 and ERG genomic sequences coupled with paired-end next generation sequencing to resolve genomic rearrangement breakpoints in TMPRSS2 and ERG at nucleotide resolution in a large series of primary prostate cancer specimens (n = 83). This strategy showed >90% sensitivity and specificity in identifying TMPRSS2-ERG rearrangements, and allowed identification of intra- and inter-chromosomal rearrangements involving TMPRSS2 and ERG with known and novel fusion partners. Our results indicate that rearrangement breakpoints show strong clustering in specific intronic regions of TMPRSS2 and ERG. The observed TMPRSS2-ERG rearrangements often exhibited complex chromosomal architecture associated with several intra- and inter-chromosomal rearrangements. Nucleotide resolution analysis of breakpoint junctions revealed that the majority of TMPRSS2 and ERG rearrangements (~88%) occurred at or near regions of microhomology or involved insertions of one or more base pairs. This architecture implicates nonhomologous end joining (NHEJ) and microhomology mediated end joining (MMEJ) pathways in the generation of such rearrangements. These analyses have provided important insights into the molecular mechanisms involved in generating prostate cancer-specific recurrent rearrangements.
TMPRSS2; ERG; rearrangement; hybrid capture; targeted next generation sequencing; prostate cancer; genomic breakpoint detection
Bone is a positive regulator of male fertility, which indicates a link between regulation of bone remodeling and reproduction or more specifically a link between calcium and androgens. This possibly suggests how calcium is linked to prostate cancer development through its link with the reproductive system. We studied serum calcium and sex steroid hormones in the Third National Health and Nutrition Examination Survey (NHANES III).
Serum calcium and sex steroid hormones were measured for 1,262 men in NHANES III. We calculated multivariable-adjusted geometric means of serum concentrations of total and estimated free testosterone and estradiol, androstanediol glucuronide (AAG), and sex hormone binding globulin (SHBG) by categories of calcium (lowest 5% [<1.16 mmol/L], mid 90%, top 5% [≥1.30 mmol/L]).
Levels of total and free testosterone, total estradiol, or AAG did not differ across categories of serum calcium. Adjusted SHBG concentrations were 36.4 for the bottom 5%, 34.2 for the mid 90%, and 38.9 nmol/L for the top 5% of serum calcium (Ptrend=0.006), free estradiol levels were 0.88, 0.92, and 0.80 pg/ml (Ptrend=0.048).
This link between calcium and sex steroid hormones, in particular the U-shaped pattern with SHBG, may, in part, explain why observational studies have found a link between serum calcium and risk of prostate cancer.
cross-sectional studies; gonadal steroid hormones; serum calcium
Prostatic inflammation has been linked to a number of prostatic diseases such as benign prostatic hyperplasia (BPH), prostatitis syndromes, and prostate cancer. Major unanswered questions include what pathogenic mechanisms, such as bacterial infections, may drive the accumulation of inflammatory infiltrates in the human prostate, and how inflammation might contribute to disease. To study this potential link in an in vivo system, we developed a mouse model of long-term bacteria-induced chronic inflammation of the prostate using a human prostatectomy-derived strain of Propionibacterium acnes.
C57BL/6J mice were inoculated, via urethral catheterization, with vehicle control or a prostatectomy-derived strain of P. acnes (PA2). Animals were assessed at 2 days, 1, 2, or 8 weeks post-inoculation via histology and immunohistochemistry (IHC).
PA2 inoculation resulted in severe acute and chronic inflammation confined to the dorsal lobe of the prostate. Chronic inflammation persisted for at least 8 weeks post-inoculation. Inflammatory lesions were associated with an increase in the Ki-67 proliferative index, and diminished Nkx3.1 and androgen receptor (AR) production. Interestingly, the observed response required live bacteria and both IHC and in situ hybridization assays for P. acnes indicated a potential intracellular presence of P. acnes in prostate epithelial cells.
To our knowledge, this is the first mouse model of long-term prostatic inflammation induced by P. acnes, and more generally, any prostatectomy-derived bacterial isolate. This model may serve as a valuable preclinical model of chronic prostatic inflammation that can be used to mechanistically study the link between inflammation and prostatic disease.
prostate; Propionibacterium acnes; inflammation; mouse model
Contrary to the hypothesis that the racial/ethnic disparity in prostate cancer has a hormonal basis, we did not observe a difference in serum testosterone concentration between non-Hispanic black and white men in the Third National Health and Nutrition Examination Survey (NHANES III), although non-Hispanic black men had a higher estradiol level. Unexpectedly, Mexican-American men had the highest testosterone level. Next, we evaluated whether the same patterns are observed during adolescence, the time of prostate maturation.
We measured serum testosterone, estradiol, and sex hormone binding globulin (SHBG) by immunoassay in 134 males aged 12–19 in NHANES III. Mean concentrations were compared by race/ethnicity adjusting for age, Tanner stage, percent body fat, waist, physical activity, tobacco smoke, and the other hormones.
After multivariable adjustment, in the 12–15 year-old males, testosterone concentration was lower in non-Hispanic blacks than whites (P=0.043), SHBG concentration did not significantly differ between the two groups. Mexican-Americans had the highest testosterone (versus non-Hispanic black: P=0.002) and lowest SHBG (versus non-Hispanic white: P=0.010; versus non-Hispanic black: P=0.047) concentrations. Estradiol concentration was lower in non-Hispanic blacks (P=0.11) and Mexican-Americans (P=0.033) compared with non-Hispanic whites. After multivariable adjustment, in the 16–19 year-old males, testosterone, estradiol, and SHBG concentrations did not differ between non-Hispanic blacks and whites. Mexican-Americans had the highest testosterone concentration (versus non-Hispanic white: P=0.08), but did not differ from the other groups on estradiol and SHBG concentrations. In both age groups, these patterns were generally present, but less pronounced after adjusting for age and Tanner stage only.
In adolescent males, non-Hispanic blacks did not have a higher testosterone concentration than non-Hispanic whites, and Mexican-Americans had the highest testosterone concentration, patterns similar to adult males.
testosterone; adolescence; race and ethnicity
The heterocyclic amine, 2-amino-1-methyl-6-phenylimidazo[4,5-B]pyridine (PhIP), found in meats cooked at high temperatures, has been implicated in epidemiological and rodent studies for causing breast, prostate, and colorectal cancers. A previous animal study using a xenograft model has shown that whole tomato and broccoli, when eaten in combination, exhibit a marked effect on tumor reduction compared to when eaten alone. Our aim was to determine if PhIP-induced carcinogenesis can be prevented by dietary consumption of whole tomato + broccoli powders. Male Fischer 344 rats (n = 45) were randomized into the following treatment groups: control (AIN93G diet), PhIP (200 ppm in AIN93G diet for the first 20 weeks of the study), or tomato + broccoli + PhIP (mixed in AIN93G diet at 10% each and fed with PhIP for 20 weeks, and then without PhIP for 32 weeks). Study animals were monitored for 52 weeks and were euthanized as necessary based on a set of criteria for health status and tumor burden. Although there appeared to be some hepatic and intestinal toxicity due to the combination of PhIP and tomato + broccoli, these rodents had improved survival and reduced incidence and/or severity of PhIP-induced neoplastic lesions compared to the PhIP-alone treated group. Rats eating tomato + broccoli exhibited a marked decrease in the number and size of cribiform prostatic intraepitheilial neoplasia/carcinoma in situ (cribiform PIN/CIS) lesions and in the incidence of invasive intestinal adenocarcinomas and skin carcinomas. Although the apparent toxic effects of combined PhIP and tomato + broccoli need additional study, the results of this study support the hypothesis that a diet rich in tomato and broccoli can reduce or prevent dietary carcinogen-induced cancers.
Obesity is associated with a variety of chronic diseases, including cancer, which may partly be explained by its influence on sex steroid hormone concentrations. Whether different measures of obesity, i.e., body mass index (BMI), waist circumference, and percent body fat were differentially associated with circulating levels of sex steroid hormones was examined in 1,265 men, aged 20 to 90+ years, attending the morning examination session of the Third National Health and Nutrition Examination Survey (NHANES III).
Methods and Methods
Serum hormones were measured by immunoassay. Weight, height, and waist circumference were measured by trained staff. Percent body fat was estimated from bioelectrical impedance. Multivariate linear regression was used to estimate associations between body fatness measures and hormone levels.
Total and free testosterone and sex hormone binding globulin concentrations decreased, whereas total and free estradiol increased with increasing BMI, waist circumference, and percent body fat (all P-trend <0.05). The magnitude of change in these hormones was similar for a one quartile increase in each body fatness measure.
Measured BMI, waist circumference, and percent body fat led to similar inferences about their association with hormone levels in men.
NHANES III; testosterone; estradiol; obesity
Recent controversies surrounding prostate cancer overtreatment emphasize the critical need to delineate the molecular features associated with progression to lethal metastatic disease. Here, we have used whole-genome sequencing and molecular pathological analyses to characterize the lethal cell clone in a patient who died of prostate cancer. We tracked the evolution of the lethal cell clone from the primary cancer to metastases through samples collected during disease progression and at the time of death. Surprisingly, these analyses revealed that the lethal clone arose from a small, relatively low-grade cancer focus in the primary tumor, and not from the bulk, higher-grade primary cancer or from a lymph node metastasis resected at prostatectomy. Despite being limited to one case, these findings highlight the potential importance of developing and implementing molecular prognostic and predictive markers, such as alterations of tumor suppressor proteins PTEN or p53, to augment current pathological evaluation and delineate clonal heterogeneity. Furthermore, this case illustrates the potential need in precision medicine to longitudinally sample metastatic lesions to capture the evolving constellation of alterations during progression. Similar comprehensive studies of additional prostate cancer cases are warranted to understand the extent to which these issues may challenge prostate cancer clinical management.
Low or high hematocrit levels are associated with increased morbidity and mortality, mediated via anemia or thromboembolic events, respectively. It is therefore important to identify factors that influence hematocrit. Although androgens are known to stimulate hematopoietic cells, it is unknown whether circulating sex steroid hormones affect hematocrit. The association between serum sex steroid hormone concentrations and hematocrit in men aged ≥20 years was evaluated in a cross-sectional study of 1273 men in the Third National Health and Nutrition Examination Survey (1988–1991). Outcomes were low (<10th percentile), high (>90th percentile), and mean hematocrit. Men with low free testosterone levels had a lower hematocrit than men with normal free testosterone levels (P = .03), although no relationship was found between total testosterone level and hematocrit. The relationship between sex hormone–binding globulin (SHBG) and hematocrit was complex, with both low (P < .001) and high (P = .01) SHBG levels associated with lower hematocrit in men aged ≥20 years and only high (P = .01) SHBG levels in men aged ≥50 years. The odds ratio (OR) of high vs normal hematocrit increased as total estradiol (OR, 2.84; P trend = .04) and free estradiol (OR, 2.23; P trend = .09) levels increased. In this nationally representative study of men, sex steroid hormone levels, particularly low free testosterone and high SHBG levels, were associated with lower hematocrit, and high total and free estradiol levels were associated with high hematocrit. Thus, changes in sex hormone levels with aging may contribute to the increased prevalence of anemia and thromboembolic stroke in men as they age.
Testosterone; estradiol; sex hormone–binding globulin; NHANES III
Hypomethylation of CpG dinucleotides in genomic DNA was one of the first somatic epigenetic alterations discovered in human cancers. DNA hypomethylation is postulated to occur very early in almost all human cancers, perhaps facilitating genetic instability and cancer initiation and progression. We therefore examined the nature, extent, and timing of DNA hypomethylation changes in human prostate cancer. Contrary to the prevailing view that global DNA hypomethylation changes occur extremely early in all human cancers, we show that reductions in 5meC content in the genome occur very late in prostate cancer progression, appearing at a significant extent only at the stage of metastatic disease. Furthermore, we found that while some LINE1 promoter hypomethylation does occur in primary prostate cancers compared to normal tissues, this LINE1 hypomethylation is significantly more pronounced in metastatic prostate cancer. Next, we carried out a tiered, gene expression microarray and bisulfite genomic sequencing based approach to identify genes that are silenced by CpG island methylation in normal prostate cells but become over-expressed in prostate cancer cells as a result of CpG island hypomethylation. Through this analysis we show that a class of cancer testis antigen genes undergoes CpG island hypomethylation and over-expression in primary prostate cancers, but more so in metastatic prostate cancers. Finally, we show that DNA hypomethylation patterns are quite heterogeneous across different metastatic sites within the same patients. These findings provide evidence that DNA hypomethylation changes occur later in prostate carcinogenesis than the CpG island , and occur heterogeneously during prostate cancer progression and metastatic dissemination.
DNA methylation; hypomethylation; prostate cancer; metastasis; epigenetics; LINE1; tumor heterogeneity; cancer testis antigens
To investigate serologic evidence of infection by cytomegalovirus (CMV), a herpesvirus with known oncogenic potential that has been detected in malignant prostate tissue, in relation to prostate cancer (PCa) risk in a large case-control study nested in the Prostate Cancer Prevention Trial (PCPT).
Cases were men with a confirmed diagnosis of PCa after visit 2 (n=614) and controls were men not diagnosed with PCa during the trial who also had a negative end-of-study biopsy (n=616). Controls were frequency-matched to cases by age, treatment arm, and family history of PCa. Sera from visit 2 were tested for CMV IgG antibodies.
No association was observed between CMV serostatus and PCa risk (adjusted CMV seroprevalence=67.9% for cases and 65.2% for controls, odds ratio=1.13, 95% confidence interval: 0.89–1.45).
Considering our null findings in the context of the full CMV literature, CMV infection, as measured by serostatus, does not appear to increase PCa risk.
Cytomegalovirus; infection; prostate cancer; epidemiology
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.
The persistence leukemia stem cells (LSCs) in chronic myeloid leukemia (CML) despite tyrosine kinase inhibition (TKI) may explain relapse after TKI withdrawal. Here we performed genome-wide transcriptome analysis of highly refined CML and normal stem and progenitor cell populations to identify novel targets for the eradication of CML LSCs using exon microarrays. We identified 97 genes that were differentially expressed in CML versus normal stem and progenitor cells. These included cell surface genes significantly upregulated in CML LSCs: DPP4 (CD26), IL2RA (CD25), PTPRD, CACNA1D, IL1RAP, SLC4A4, and KCNK5. Further analyses of the LSCs revealed dysregulation of normal cellular processes, evidenced by alternative splicing of genes in key cancer signaling pathways such as p53 signaling (e.g. PERP, CDKN1A), kinase binding (e.g. DUSP12, MARCKS), and cell proliferation (MYCN, TIMELESS); downregulation of pro-differentiation and TGF-β/BMP signaling pathways; upregulation of oxidative metabolism and DNA repair pathways; and activation of inflammatory cytokines, including CCL2, and multiple oncogenes (e.g., CCND1). These data represent an important resource for understanding the molecular changes in CML LSCs, which may be exploited to develop novel therapies for eradication these cells and achieve cure.
chronic myeloid leukemia; CML; leukemic stem cell; LSC; normal hematopoietic stem cell; HSC; myeloid progenitor cells; CD34; CD38; ALDH; IL2RA; CD25; DPP4; CD26; GAS2
About 20% of all human cancers are caused by chronic infection or chronic inflammatory states. Recently, a new hypothesis has been proposed for prostate carcinogenesis. It proposes that exposure to environmental factors such as infectious agents and dietary carcinogens, and hormonal imbalances lead to injury of the prostate and to the development of chronic inflammation and regenerative ‘risk factor’ lesions, referred to as proliferative inflammatory atrophy (PIA). By developing new experimental animal models coupled with classical epidemiological studies, genetic epidemiological studies and molecular pathological approaches, we should be able to determine whether prostate cancer is driven by inflammation, and if so, to develop new strategies to prevent the disease.
Vitamin E may protect against prostate cancer, possibly only in smokers and, we hypothesize, through altered sex steroid hormones. A controlled trial in smokers showed that sex hormone levels were inversely associated with baseline serum α-tocopherol and decreased in response to vitamin E supplementation. The vitamin E-hormone relation is understudied in non-smokers.
Serum sex steroid hormones and α-tocopherol were measured for 1,457 men in NHANES III. Multivariable-adjusted geometric mean hormone concentrations by α-tocopherol quintile were estimated.
We observed lower mean testosterone, estradiol, and SHBG concentrations with increasing serum α-tocopherol (Q1=5.5 and Q5=4.6 ng/mL, p-trend=0.0007; Q1=37.8 and Q5=33.1 pg/mL, p-trend=0.02; Q1=38.8 and Q5=30.6 pg/mL, p-trend=0.05, respectively). Interactions between serum α-tocopherol and exposure to cigarette smoke for total testosterone, total estradiol, and SHBG were found with the inverse relation observed only among smokers.
Results from this nationally representative, cross-sectional study indicate an inverse association between serum α-tocopherol and circulating testosterone, estradiol, and SHBG, but only in men who smoked. Our findings support vitamin E selectively influencing sex hormones in smokers, and afford possible mechanisms through which vitamin E may impact prostate cancer risk.
Gonadal Steroid Hormones; alpha-Tocopherol; Smoking; Prostatic Neoplasms; Cross-Sectional Studies