The TMPRSS2:ERG fusion and response to androgen deprivation therapy for prostate cancer

Semi-Supervised, Attention-Based Deep Learning for Predicting TMPRSS2:ERG Fusion Status in Prostate Cancer Using Whole Slide Images

IMPLICATIONS

Our study illuminates the potential of deep learning in effectively inferring key prostate cancer genetic alterations from the tissue morphology depicted in routinely available histology slides, offering a cost-effective method that could revolutionize diagnostic strategies in oncology.

Pre-Clinical Models to Study Human Prostate Cancer

Prostate cancer is a common cancer among men and typically progresses slowly for several decades before becoming aggressive and spreading to other organs, leaving few treatment options. While large animals have been studied, the dog's prostate is anatomically similar to humans and has been used to study spontaneous prostate cancer. However, most research currently focuses on the mouse as a model organism due to the ability to genetically modify their prostatic tissues for molecular analysis. One milestone in this research was the identification of the prostate-specific promoter Probasin, which allowed for the prostate-specific expression of transgenes. This has led to the generation of mice with aggressive prostatic tumors through overexpression of the SV40 oncogene. The Probasin promoter is also used to drive Cre expression and has allowed researchers to generate prostate-specific loss-of-function studies. Another landmark moment in the process of modeling prostate cancer in mice was the orthoptic delivery of viral particles. This technology allows the selective overexpression of oncogenes from lentivirus or the use of CRISPR to generate complex loss-of-function studies. These genetically modified models are complemented by classical xenografts of human prostate tumor cells in immune-deficient mice. Overall, pre-clinical models have provided a portfolio of model systems to study and address complex mechanisms in prostate cancer for improved treatment options. This review will focus on the advances in each technique.

Computational design of DNA binding domain-retained fusion proteins and virtual screening against FDA-approved drugs

Even though the transcription factors (TFs) are not regarded as good drug targets, mutated or dysregulated TFs can be a unique class of drug targets. Specifically, the TF fusion protein, which is the translated structural variants including TFs may affect downstream to promote tumorigenesis. To date, we lack the fusion protein sequence information and 3D structure information in identifying the potential drugs of fusion proteins. In this study, we predicted the 3D structures of 732 transcription factor fusion proteins (TFFPs). For the top five most frequent TFFPs, we performed the virtual screening across the FDA-approved drugs. Our study will provide an initial platform to develop novel therapeutic targets in the transcription factor fusion proteins.

To bind or not to bind: Cistromic reprogramming in prostate cancer

The term “cistrome” refers to the genome-wide location of regulatory elements associated with transcription factor binding-sites. The cistrome of key regulatory factors in prostate cancer etiology are substantially reprogrammed and altered during prostatic transformation and disease progression. For instance, the cistrome of the androgen receptor (AR), a ligand-inducible transcription factor central in normal prostate epithelium biology, is directly impacted and substantially reprogrammed during malignant transformation. Accumulating evidence demonstrates that additional transcription factors that are frequently mutated, or aberrantly expressed in prostate cancer, such as the pioneer transcription factors Forkhead Box A1 (FOXA1), the homeobox protein HOXB13, and the GATA binding protein 2 (GATA2), and the ETS-related gene (ERG), and the MYC proto-oncogene, contribute to the reprogramming of the AR cistrome. In addition, recent findings have highlighted key roles for the SWI/SNF complex and the chromatin-modifying helicase CHD1 in remodeling the epigenome and altering the AR cistrome during disease progression. In this review, we will cover the role of cistromic reprogramming in prostate cancer initiation and progression. Specifically, we will discuss the impact of key prostate cancer regulators, as well as the role of epigenetic and chromatin regulators in relation to the AR cistrome and the transformation of normal prostate epithelium. Given the importance of chromatin-transcription factor dynamics in normal cellular differentiation and cancer, an in-depth assessment of the factors involved in producing these altered cistromes is of great relevance and provides insight into new therapeutic strategies for prostate cancer.

Insufficient Lycopene Intake Is Associated With High Risk of Prostate Cancer: A Cross-Sectional Study From the National Health and Nutrition Examination Survey (2003-2010)

Although lycopene intake and risk of prostate cancer have been explored for decades, recent studies show that Non-Hispanic Black Prostate Cancer (PCa) patients benefit less than Non-Hispanic White patients from a lycopene intake intervention program. This study examined whether a lycopene intake-related racial disparity exists in reducing the risk of PCa in healthy adults. Data on healthy, cancer-free Non-Hispanic Black (NHB) men (n = 159) and Non-Hispanic White (NHW) men (n = 478) from the 2003 to 2010 NHANES dataset were analyzed. Total lycopene intake from daily diet, age, living status, race/ethnicity, education level, poverty income ratio, body mass index, and smoking status were studied as independent variables. The combination of total Prostate-Specific Antigen (PSA) level and the ratio of free PSA was set as criteria for evaluating the risk of PCa. Multivariable logistic regression was used in race-stratified analyses to compute odds ratios (OR) and 95% confidence intervals (95% CI) comparing high PCa risk with low PCa risk. We found, in the whole population, race/ethnicity was the only factor that influenced lycopene intake from the daily diet. NHB men consumed less lycopene than NHW men (3,716 vs. 6,487 (mcg), p = 0.01). Sufficient lycopene intake could reduce the risk of PCa (OR: 0.40, 95% CI: 0.18-0.85, p = 0.02). Men aged between 66 and 70 had high PCa risk (OR: 3.32, 95% CI: 1.12-9.85, p = 0.03). Obesity served as a protective factor against the high risk of PCa (OR: 0.25, 95% CI: 0.12-0.54, p = 0.001). NHW men aged between 66 and 70 had a high risk of PCa (OR: 4.01, 95% CI: 1.02-15.73, p = 0.05). Obese NHW men also had lower risk of PCa (OR: 0.18, 95% CI: 0.07-0.47 p = 0.001). NHB men had a high risk of PCa compared to NHW men (OR: 2.27, 95% CI: 1.35-3.81 p = 0.004). NHB men who were living without partners experienced an even higher risk of PCa (OR: 3.35, 95% CI: 1.01-11.19 p = 0.07). Sufficient lycopene intake from daily food could serve as a protector against PCa. Such an association was only observed in NHW men. Further studies are needed to explore the dose-response relationship between lycopene intake and the association of PCa risk in NHB men.

Androgen Receptor Signaling in Prostate Cancer Genomic Subtypes

While many prostate cancer (PCa) cases remain indolent and treatable, others are aggressive and progress to the metastatic stage where there are limited curative therapies. Androgen receptor (AR) signaling remains an important pathway for proliferative and survival programs in PCa, making disruption of AR signaling a viable therapy option. However, most patients develop resistance to AR-targeted therapies or inherently never respond. The field has turned to PCa genomics to aid in stratifying high risk patients, and to better understand the mechanisms driving aggressive PCa and therapy resistance. While alterations to the AR gene itself occur at later stages, genomic changes at the primary stage can affect the AR axis and impact response to AR-directed therapies. Here, we review common genomic alterations in primary PCa and their influence on AR function and activity. Through a meta-analysis of multiple independent primary PCa databases, we also identified subtypes of significantly co-occurring alterations and examined their combinatorial effects on the AR axis. Further, we discussed the subsequent implications for response to AR-targeted therapies and other treatments. We identified multiple primary PCa genomic subtypes, and given their differing effects on AR activity, patient tumor genetics may be an important stratifying factor for AR therapy resistance.

Epidemiology and genomics of prostate cancer in Asian men

Prostate cancer is a global health problem, but incidence varies considerably across different continents. Asia is traditionally considered a low-incidence area, but the incidence and mortality of prostate cancer have rapidly increased across the continent. Substantial differences in epidemiological features have been observed among different Asian regions, and incidence, as well as mortality-to-incidence ratio, is associated with the human development index. Prostate cancer mortality decreased in Japan and Israel from 2007 to 2016, but mortality has increased in Thailand, Kyrgyzstan and Uzbekistan over the same period. Genomic analyses have shown a low prevalence of ERG oncoprotein in the East Asian population, alongside a low rate of PTEN loss, high CHD1 enrichments and high FOXA1 alterations. Contributions from single-nucleotide polymorphisms to prostate cancer risk vary with ethnicity, but germline mutation rates of DNA damage repair genes in metastatic prostate cancer are comparable in Chinese and white patients from the USA and UK. Pharmacogenomic features of testosterone metabolism might contribute to disparities seen in the response to androgen deprivation between East Asian men and white American and European men. Overall, considerable diversity in epidemiology and genomics of prostate cancer across Asia defines disease characteristics in these populations, but studies in this area are under-represented in the literature. Taking into account this intracontinental and intercontinental heterogeneity, translational studies are required in order to develop ethnicity-specific treatment strategies.

Clinical Actionability of the Genomic Landscape of Metastatic Castration Resistant Prostate Cancer

The development of targeted therapies increases treatment options for metastatic castration resistant prostate cancer (mCRPC) patients. There is a need for strong predictive and prognostic signatures to guide physicians in treating mCRPC patients. In this review we unravel the possible actionability in the AR pathway, PI3K AKT signaling, and DNA repair pathways. Additionally, we make recommendations on biomarker trial design, and the clinical use of this new type of data.

Diversity in Androgen Receptor Action Among Treatment-naïve Prostate Cancers Is Reflected in Treatment Response Predictions and Molecular Subtypes

Background

Metastatic prostate cancer (CaP) treatments are evolving rapidly but without evidence-based biomarkers to predict responses, and to maximize remissions and survival.

Objective

To determine the activity of androgen receptor (AR), the target for default first-line systemic treatment, in localized treatment-naïve CaP and its association with clinical risk factors, molecular markers, CaP subtypes, and predictors of treatment response.

Design setting and participants

We examined 452 bona fide AR target genes in clinical-grade expression profiles from 6532 such CaPs collected between 2013 and 2017 by US physicians ordering the Decipher RP test. Results were validated in three independent smaller cohorts (n = 73, 90, and 127) and clinical CaP AR ChIP-Seq data. Association with CaP differentiation and progression was analyzed in independent datasets.

Outcome measurements and statistical analysis

Unsupervised clustering of CaPs based on AR target gene expression was aligned with clinical variables, differentiation scores, molecular subtypes, and predictors of response to hormonal therapy, radiotherapy, and chemotherapy. AR target gene sets were analyzed via Gene Set Enrichment Analysis for differentiation and treatment resistance, Ingenuity Pathway Analysis for associated biology, and Cistrome for genomic AR binding site (ARBS) composition.

Results and limitations

Expression of eight AR target gene subsignatures gave rise to five CaP clusters, which were preferentially associated with CaP molecular subtypes, differentiation, and predictors of treatment response rather than with clinical variables. Subsignatures differed in contribution to CaP progression, luminal/basal differentiation, CaP biology, and ARBS composition. Validation in prospective trials and optimized quantitation are needed for clinical implementation.

Conclusions

Measurement of AR activity patterns in treatment-naïve CaP may serve as a first branch of an evidence-based decision tree to optimize personalized treatment plans.

Patient summary

Treatment options for metastatic prostate cancer are increasing without information needed to choose the right treatment for the right patient. We found variation in the behavior of the target for the default first-line therapy before treatment, which may help optimize treatment plans.

SFRP1 increases TMPRSS2-ERG expression promoting neoplastic features in prostate cancer in vitro and in vivo

Background

Prostate cancer (PCa) is the second cause of cancer related death in North American men. Androgens play an important role in its progression by regulating the expression of several genes including fusion ones that results from structural chromosome rearrangements. TMPRSS2-ERG is a fusion gene commonly observed in over 50% of PCa tumors, and its expression can be transcriptionally regulated by the androgen receptor (AR) given its androgen responsive elements. TMPRSS2-ERG could be involved in epithelial–mesenchymal transition (EMT) during tumor development. ERG has been reported as a key transcriptional factor in the AR-ERG-WNT network where five SFRP proteins, structurally similar to WNT ligands and considered to be WNT pathway antagonists, can regulate signaling in the extracellular space  by binding to WNT proteins or Frizzled receptors. It has been shown that over-expression of SFRP1 protein can regulate the transcriptional activity of AR and inhibits the formation of colonies in LNCaP cells. However, the effect of SFRP1 has been controversial since differential effects have been observed depending on its concentration and tissue location. In this study, we explored the role of exogenous SFRP1 protein in cells expressing the TMPRSS2-ERG fusion.

Methods

To evaluate the effect of exogenous SFRP1 protein on PCa cells expressing TMPRSS2-ERG, we performed in silico analysis from TCGA cohort, expression assays by RT-qPCR and Western blot, cell viability and cell cycle measurements by cytometry, migration and invasion assays by xCELLigance system and murine xenografts.

Results

We demonstrated that SFRP1 protein increased ERG expression by promoting cellular migration in vitro and increasing tumor growth in vivo in PCa cells with the TMPRSS2-ERG fusion.

Conclusions

These results suggest the possible role of exogenous SFRP1 protein as a modulator of AR-ERG-WNT signaling network in cells positive to TMPRSS2-ERG. Further, investigation is needed to determine if SFRP1 protein could be a target in against this type of PCa.

First comprehensive computational analysis of functional consequences of TMPRSS2 SNPs in susceptibility to SARS-CoV-2 among different populations

Current SARS-CoV-2 pandemy mortality created the hypothesis that some populations may be more susceptible to SARS-CoV-2. TMPRSS2 encodes a transmembrane serine protease which plays a crucial role in SARS-CoV-2 cell entry. Single nucleotide polymorphisms (SNPs) in TMPRSS2 might influence SARS-CoV2 entry into the cell. This study aimed to investigate the impact of SNPs on TMPRSS2 function and structure. In silico tools such as Ensembl, Gtex, ExPASY 2, GEPIA, CCLE, KEGG and GO were engaged to characterize TMPRSS2 and its expression profile. The functional effects of SNPs were analyzed by PolyPhen-2, PROVEN, SNAP2, SIFT and HSF. Also, Phyre2, GOR IV and PSIPRED were used to predict the secondary structure of TMPRSS2. Moreover, post-translational modification (PTM) and secretory properties were analyzed through Modpredand Phobius, respectively. Finally, miRNA profiles were investigated by PolymiRTS and miRSNPs. Out of 11,184 retrieved SNPs from dbSNP, 92 showed a different frequency between Asians and other populations. Only 21 SNPs affected the function and structure of TMPRSS2 by influencing the protein folding, PTM, splicing and miRNA function. Particularly, rs12329760 may create a de novo pocket protein. rs875393 can create a donor site, silencer and broken enhancer motifs. rs12627374 affects a wide spectrum of miRNAs profile. This study highlighted the role of TMPRSS2 SNPs and epigenetic mechanisms especially non-coding RNAs in appearance of different susceptibility to SARS-CoV-2 among different populations. Also, this study could pave the way to potential therapeutic implication of TMPRSS2 in designing antiviral drugs.

Communicated by Ramaswamy H. Sarma

ETS-related gene (ERG) expression as a predictor of oncological outcomes in patients with high-grade prostate cancer treated with primary androgen deprivation therapy: a cohort study

OBJECTIVES

To determine whether ETS-related gene (ERG) expression can be used as a biomarker to predict biochemical recurrence and prostate cancer-specific death in patients with high Gleason grade prostate cancer treated with androgen deprivation therapy (ADT) as monotherapy.

METHODS

A multicentre retrospective cohort study identifying 149 patients treated with primary ADT for metastatic or non-metastatic prostate cancer with Gleason score 8-10 between 1999 and 2006. Patients planned for adjuvant radiotherapy at diagnosis were excluded. Age at diagnosis, ethnicity, prostate-specific antigen and Charlson-comorbidity score were recorded. Prostatic tissue acquired at biopsy or transurethral resection surgery was assessed for immunohistochemical expression of ERG. Failure of ADT defined as prostate specific antigen nadir +2. Vital status and death certification data determined using the UK National Cancer Registry. Primary outcome measures were overall survival (OS) and prostate cancer specific survival (CSS). Secondary outcome was biochemical recurrence-free survival (BRFS).

RESULTS

The median OS of our cohort was 60.2 months (CI 52.0 to 68.3). ERG expression observed in 51/149 cases (34%). Multivariate Cox proportional hazards analysis showed no significant association between ERG expression and OS (p=0.41), CSS (p=0.92) and BRFS (p=0.31). Cox regression analysis showed Gleason score (p=0.003) and metastatic status (p<1×10^-5) to be the only significant predictors of prostate CSS.

CONCLUSIONS

No significant association was found between ERG status and any of our outcome measures. Despite a limited sample size, our results suggest that ERG does not appear to be a useful biomarker in predicting response to ADT in patients with high risk prostate cancer.

Genomics of adult and pediatric solid tumors

Different types of cancers exhibit disparate spectra of genomic alterations (germline and/or somatic). These alterations can include single nucleotide variants (SNVs), copy number alterations (CNAs) or structural changes (e.g. gene fusions and chromosomal rearrangements). Identification of those genomic alterations has provided the opportune element to derive new strategies for molecular-based precision medicine of adult and pediatric cancers including risk assessment, non-invasive detection, molecular diagnosis and personalized therapy. Moreover, it is now becoming clear that the spectra of genomic-based alterations and mechanisms in pediatric malignancies are different from those predominantly occurring in adult cancer. Adult cancers on average exhibit substantially higher mutational burdens compared with the vast majority of childhood tumors. Accumulating evidence also suggests that the type of genomic alterations frequently encountered in adult cancers is different from those observed in pediatric malignancies. In this review, we discuss the state of knowledge on adult and pediatric cancer genomes (or "mutatomes"), specifically focusing on solid tumors. We present an overview of mutational signatures and processes in cancer as well as comprehensively compare and contrast the diverse spectra of genomic alterations (somatic and familial) among major adult and pediatric solid tumors. The review also discusses the role of genomics in molecular-based precision medicine of adult and pediatric solid malignancies as well as comprehending resistance mechanisms to various targeted therapies. In addition, we present a perspective that discusses upon emerging concepts in cancer genomics including intratumoral heterogeneity, the precancer (premalignant) genome as well as the interface between the host immune response and tumor genome - immunogenomics - as they relate to adult and pediatric tumors.

TMPRSS2-ERG fusions unexpectedly identified in men initially diagnosed with nonprostatic malignancies

Background

TMPRSS2-ERG gene fusions are frequently found in prostate cancer and are pathognomomic for prostatic origin. In a series of cancer cases assayed with comprehensive genomic profiling (CGP) in the course of clinical care, we reviewed the frequency of TMPRSS2-ERG fusions in patient tumors of various histologic subtypes.

Methods

Frequency of TMPRSS2-ERG fusions was determined in comprehensive genomic profiles from 64,263 cancer cases submitted to Foundation Medicine to assess genomic alterations suggesting benefit from targeted therapy. Genomic results from an index case of prostate cancer that underwent evolution from adenocarcinoma to pure squamous cell carcinoma are presented.

Results

TMPRSS2-ERG fusions were identified for 0.86% (250/29030) of male patients and not found for female patients (0/35233). TMPRSS2-ERG fusions were detected in six tumors that were classified as squamous carcinoma, five of which were of unknown primary site. The index case is a patient with a large left retrovesical mass diagnosed as squamous carcinoma by morphologic examination and a history of Gleason 9 prostate cancer with prior prostatectomy and salvage radiation therapy. TMPRSS2-ERG was detected by genomic profiling in the squamous cell tumor, the primary adenocarcinoma of the prostate, and in a metachronous prostatic adenocarcinoma metastasis. Based on these results, the patient received androgen deprivation therapy. A phylogenetic tree demonstrating clonal and histopathologic evolution of prostate cancer in the index patient was constructed.

Conclusions

In this large CGP dataset, TMPRSS2-ERG fusion was seen in ~30% of prostate cancers regardless of histologic type; the fusion was on occasion detected in advanced cancers not initially carrying a diagnosis of prostate carcinoma. CGP of advanced cancers in men may reveal prostatic origin by detection of the pathognomomic TMPRSS2-ERG fusion gene.

Ethnicity and ERG frequency in prostate cancer

Emerging observations emphasize a distinct biology of prostate cancer among men of different ethnicities and races, as demonstrated by remarkable differences in the frequency of ERG oncogenic activation, one of the most common and widely studied prostate cancer driver genes. Worldwide assessment of ERG alterations frequencies show consistent trends, with men of European ancestry having the highest rates of alteration and men of African or Asian ancestries having considerably lower alteration rates. However, data must be interpreted cautiously, owing to variations in assay platforms and specimen types, as well as ethnic and geographical classifications. Many opportunities and challenges remain in assessing cancer-associated molecular alterations at a global level, and these need to be addressed in order to realize the true potential of precision medicine for all cancer patients.

Noninvasive Prenatal Diagnosis Significance of ERG Methylation as a Biomarker in Down's Syndrome

Background

Down’s syndrome (DS) is a genetic disease with chromosome abnormality due to the increasing chromosome 21. This study focused on the clinical application value of ERG methylation level in blood of pregnant women as a biomarker in Down’s syndrome.

Material/Methods

The sham group consisted of 210 nonpregnant women, the positive control group consisted of 33 women with a delivery history of DS fetus, and the negative control group consisted of 60 women with eutocia history. A combination of restriction enzyme digestion experiment and PCR was performed to examine ERG methylation levels, methylation sites, and distribution in blood of pregnant women and in chorion tissues from abortion samples. Gene sequencing was performed to determine the ERG sequence in chromosome 21. Homology between normal tissues and chorion tissues from abortion samples was analyzed with bioinformatics technology.

Results

ERG methylation in chorion tissues from 210 abortion samples at 8, 9, and 10 weeks gestational age were determined; however, no ERG methylation was determined in blood of pregnant women. Gene sequencing indicated that normal ERG sequence in chromosome 21 was in fetus chorion tissues, and these ERG sequences were aberrantly methylated. Bioinformatics result showed that homology and DNA methylation level was discrepancy in normal tissues and chorion tissues from abortion samples.

Conclusions

It was worthwhile to use ERG methylation as biomarker in noninvasive prenatal diagnosis, and ERG methylation should be applied with consent of pregnancy and her relatives.

Loss of PTEN expression in ERG-negative prostate cancer predicts secondary therapies and leads to shorter disease-specific survival time after radical prostatectomy

The clinical course of prostate cancer is highly variable. Current prognostic variables, stage, and Gleason score have limitations in assessing treatment regimens for individual patients, especially in the intermediate-risk group of Gleason score 7. ERG:TMPRSS2 fusion and loss of PTEN are some of the most common genetic alterations in prostate cancer. Immunohistochemistry of PTEN and ERG has generated interest as a promising method for more precise outcome prediction but requires further validation in population-based cohorts. We studied the predictive value of ERG and PTEN expression by immunohistochemistry in two large radical prostatectomy cohorts comprising 815 patients with extensive follow-up information. Clinical end points were initiation of secondary therapy, overall survival, and disease-specific survival. Predictions of clinical outcomes were also assessed according to androgen receptor (AR) activity. PTEN loss, especially in ERG-negative cancers, predicted initiation of secondary treatments and shortened disease-specific survival time, as well as stratifying Gleason score 7 patients into different prognostic groups with regard to secondary treatments and disease-specific survival. High AR immunoreactivity in ERG-negative cancers with PTEN loss predicted worse disease-specific survival. We also observed that in Gleason score 7 ERG-negative cases with PTEN loss and high AR expression have significantly shorter disease-specific survival time compared with ERG-positive cases. Our conclusion is that loss of PTEN is a strong determining factor for shorter disease-specific survival time and initiation of secondary therapies after radical prostatectomy. The predictive value of PTEN immunoreactivity is further accentuated in ERG-negative cancers with high AR expression. Negative PTEN expression, accompanied by ERG status, can be used to stratify patients with Gleason score 7 into different survival groups. Assessment of PTEN and ERG status could provide an additional tool for initial diagnostics when determining the prognosis and subsequent follow-up regimen for patients treated by radical prostatectomy.

Current advances in intratumoral androgen metabolism in castration-resistant prostate cancer

PURPOSE OF REVIEW

Androgen deprivation therapy is a cornerstone in the treatment of advanced prostate cancer and has extended the lives of countless patients. Unfortunately, many of these patients eventually succumb to metastatic castration-resistant prostate cancer (mCRPC). The efficacy of abiraterone acetate (AA, Zytiga) and enzalutamide (Enza, Xtandi) in the mCRPC setting prove that these tumors remain androgen-driven. We review recent studies that have shown that intratumoral androgen biosynthesis plays a significant role in the ever-evolving mCRPC tumor and we discuss the therapeutic implications of these findings.

RECENT FINDINGS

A novel abiraterone metabolite, 17-(pyridin-3-yl)androsta-4,16-dien-3-one (D4A), possesses robust antitumor activity in rodent models via the inhibition of androgen biosynthetic enzymes and antagonism of the androgen receptor. The TMPRSS2 : ERG fusion drives aldo-keto reductase 1C3 (AKR1C3) expression and activity to facilitate androgen biosynthesis and activate the androgen receptor in prostate cancer. Intracrine androgen formation and AKR1C3 expression and activity have been found to confer resistance to enzalutamide.

SUMMARY

These studies highlight the significant role that intratumoral androgen biosynthesis plays in the mCRPC tumor. The therapeutic implications include the inhibition of AKR1C3 in tumors that become resistant to current drugs such as abiraterone acetate or Enza and the potential administration of D4A as an mCRPC therapeutic.

Emerging Role of Genomic Rearrangements in Breast Cancer: Applying Knowledge from Other Cancers

Significant advances in our knowledge of cancer genomes are rapidly changing the way we think about tumor biology and the heterogeneity of cancer. Recent successes in genomically-guided treatment approaches accompanied by more sophisticated sequencing techniques have paved the way for deeper investigation into the landscape of genomic rearrangements in cancer. While considerable research on solid tumors has focused on point mutations that directly alter the coding sequence of key genes, far less is known about the role of somatic rearrangements. With many recurring alterations observed across tumor types, there is an obvious need for functional characterization of these genomic biomarkers in order to understand their relevance to tumor biology, therapy, and prognosis. As personalized therapy approaches are turning toward genomic alterations for answers, these biomarkers will become increasingly relevant to the practice of precision medicine. This review discusses the emerging role of genomic rearrangements in breast cancer, with a particular focus on fusion genes. In addition, it raises several key questions on the therapeutic value of such rearrangements and provides a framework to evaluate their significance as predictive and prognostic biomarkers.

Marchantin M Induces Apoptosis of Prostate Cancer Cells Through Endoplasmic Reticulum Stress

BACKGROUND Apoptosis is mediated by the endoplasmic reticulum (ER) stress pathway, mitochondrial pathway, and death receptor. Data herein suggested an inhibitory effect of marchantin M on tumor formation in nude mice as well as the impact on CHOP and GRP78 expression. MATERIAL AND METHODS The role of marchantin M on proliferation and apoptosis of DU145 cells were measured by MTT and flow cytometry, respectively. Western blot was applied to detect the expression of GRP78 and CHOP. The mice received abdominal injection at 1 time/2 d and 2 ml/time. Tumor volume was measured every 6 days. The mice were euthanatized 30 days after marchantin injection and tumor weight was measured. Cell apoptosis was determined by TUNEL. The expressions of CHOP and GRP78 were detected by immunohistochemistry. RESULTS Tumor size and weight in marchantin groups were significantly lower than in the control group (A, B) (P<0.05), and the inhibitory rate presented a dose-dependent increase. Compared with controls, the levels of CHOP and GRP78 expression elevated obviously following the treatment with marchantin (P<0.05). It showed statistically significant difference among groups C, D, E, with different levels of apoptosis indexes incremented in groups of marchantin H, M, L, compared with groups A and B (P<0.05). CONCLUSIONS Overall, this study shows that marchantin M circumvents the growth of prostate cancer PC-3 tumor and up-regulates expressions of CHOP and GRP78. Our data also indicate that marchantin M limits the proliferation and favors apoptosis of DU145 cells in a time- and dose-dependent manner.

The predictive value of ERG protein expression for development of castration-resistant prostate cancer in hormone-naïve advanced prostate cancer treated with primary androgen deprivation therapy

BACKGROUND

Biomarkers predicting response to primary androgen deprivation therapy (ADT) and risk of castration-resistant prostate cancer (CRPC) is lacking. We aimed to analyse the predictive value of ERG expression for development of CRPC.

METHODS

In total, 194 patients with advanced and/or metastatic prostate cancer (PCa) treated with first-line castration-based ADT were included. ERG protein expression was analysed in diagnostic specimens using immunohistochemistry (anti-ERG, EPR3864). Time to CRPC was compared between ERG subgroups using multiple cause-specific Cox regression stratified on ERG-status. Risk reclassification and time-dependent area under the ROC curves were used to assess the discriminative ability of ERG-status. Time to PSA-nadir, proportion achieving PSA-nadir ≤0.2 ng/ml, and risk of PCa-specific death were secondary endpoints.

RESULTS

Median follow-up was 6.8 years (IQR: 4.9-7.3). In total, 105 patients (54.1%) were ERG-positive and 89 (45.9%) were ERG-negative. No difference in risk of CRPC was observed between ERG subgroups (P = 0.51). Median time to CRPC was 3.9 years (95%CI: 3.2-5.1) and 4.5 years (95%CI: 2.3-not reached) in the ERG-positive and ERG-negative group, respectively. Compared to a model omitting ERG-status, the ERG-stratified model showed comparable AUC values 1 year (77.6% vs. 78.0%, P = 0.82), 2 years (71.7% vs. 71.8%, P = 0.85), 5 years (68.5% vs. 69.9%, P = 0.32), and 8 years (67.9% vs. 71.4%, P = 0.21) from ADT initiation. No differences in secondary endpoints were observed.

CONCLUSIONS

ERG expression was not associated with risk of CRPC suggesting that ERG is not a candidate biomarker for predicting response to primary ADT in patients diagnosed with advanced and/or metastatic PCa.

Effect of curcumin on Bcl-2 and Bax expression in nude mice prostate cancer

Prostate cancer is a common malignant tumor in urinary system. Curcumin has curative effect on many kinds of cancers and can inhibit prostate cancer (PC)-3 cells proliferation. This study aimed to explore the curcumin induced prostate cancer cell apoptosis and apoptosis related proteins Bcl-2 and Bax expression. PC-3 cells were injected subcutaneously to the nude mice to establish the tumor model. The nude mice were randomly divided into group C (normal saline), group B (6% polyethylene glycol and 6% anhydrous ethanol), group H, M, L (100 mg/kg, 50 mg/kg, and 25 mg/kg curcumin). The tumor volume was measured every 6 days to draw the tumor growth curve. The mice were killed at the 30(th) day after injection to weight the tumor. TUNEL assay was applied to determine cell apoptosis. Immunohistochemistry was used to detect Bcl-2 and Bax expression. The tumor volume and weight in group H, M, L were significantly lower than the control group (C, B) (P<0.05), and the inhibitory rate increased following the curcumin dose increase. Compared with the control group, Bcl-2 expression in group H, M, L gradually decreased, while Bax protein expression increased (P<0.05). The cell apoptosis rate showed no statistical difference between group B and C, while it increased in curcumin group H, M, and L (P<0.05). Curcumin could inhibit PC-3 growth, decrease tumor volume, reduce tumor weight, and induce cell apoptosis under the skin of nude mice by up-regulating Bax and down-regulating Bcl-2.