Development of EphA2 siRNA-loaded lipid nanoparticles and combination with a small-molecule histone demethylase inhibitor in prostate cancer cells and tumor spheroids

BACKGROUND

siRNAs hold a great potential for cancer therapy, however, poor stability in body fluids and low cellular uptake limit their use in the clinic. To enhance the bioavailability of siRNAs in tumors, novel, safe, and effective carriers are needed.

RESULTS

Here, we developed cationic solid lipid nanoparticles (cSLNs) to carry siRNAs targeting EphA2 receptor tyrosine kinase (siEphA2), which is overexpressed in many solid tumors including prostate cancer. Using DDAB cationic lipid instead of DOTMA reduced nanoparticle size and enhanced both cellular uptake and gene silencing in prostate cancer cells. DDAB-cSLN showed better cellular uptake efficiency with similar silencing compared to commercial transfection reagent (Dharmafect 2). After verifying the efficacy of siEphA2-loaded nanoparticles, we further evaluated a potential combination with a histone lysine demethylase inhibitor, JIB-04. Silencing EphA2 by siEphA2-loaded DDAB-cSLN did not affect the viability (2D or 3D culture), migration, nor clonogenicity of PC-3 cells alone. However, upon co-administration with JIB-04, there was a decrease in cellular responses. Furthermore, JIB-04 decreased EphA2 expression, and thus, silencing by siEphA2-loaded nanoparticles was further increased with co-treatment.

CONCLUSIONS

We have successfully developed a novel siRNA-loaded lipid nanoparticle for targeting EphA2. Moreover, preliminary results of the effects of JIB-04, alone and in combination with siEphA2, on prostate cancer cells and prostate cancer tumor spheroids were presented for the first time. Our delivery system provides high transfection efficiency and shows great promise for targeting other genes and cancer types in further in vitro and in vivo studies.

Association of Prediagnostic Blood Metabolomics with Prostate Cancer Defined by ERG or PTEN Molecular Subtypes

BACKGROUND

The TMPRSS2:ERG gene fusion and PTEN loss are two of the most common somatic molecular alterations in prostate cancer. Here, we investigated the association of prediagnostic-circulating metabolomics and prostate cancer defined by ERG or PTEN status to improve understanding of these etiologically distinct molecular prostate cancer subtypes.

METHODS

The study was performed among 277 prostate cancer cases with ERG status, 211 with PTEN status, and 294 controls nested in the Health Professionals Follow-up Study (HPFS) and the Physicians' Health Study (PHS). We profiled 223 polar and non-polar metabolites using LC-MS in prediagnostic plasma specimens. We applied enrichment analysis and multinomial logistic regression models to identify biological metabolite classes and individual metabolites associated with prostate cancer defined by ERG or PTEN status.

RESULTS

Compared with noncancer controls, sphingomyelin (P: 0.01), ceramide (P: 0.04), and phosphatidylethanolamine (P: 0.03) circulating levels were enriched among ERG-positive prostate cancer cases. Sphingomyelins (P: 0.02), ceramides (P: 0.005), and amino acids (P: 0.02) were enriched among tumors exhibiting PTEN-loss; unsaturated diacylglycerols (P: 0.003) were enriched among PTEN-intact cases; and unsaturated triacylglycerols were enriched among both PTEN-loss (P: 0.001) and PTEN-intact (P: 0.0001) cases. Although several individual metabolites identified in the above categories were nominally associated with ERG or PTEN-defined prostate cancer, none remained significant after accounting for multiple testing.

CONCLUSIONS

The molecular process of prostate carcinogenesis may be distinct for men with different metabolomic profiles.

IMPACT

These novel findings provide insights into the metabolic environment for the development of prostate cancer.

Prognostic Impact of KRAS G12C Mutation in Patients With NSCLC: Results From the European Thoracic Oncology Platform Lungscape Project

INTRODUCTION

KRAS mutations, the most frequent gain-of-function alterations in NSCLC, are currently emerging as potential predictive therapeutic targets. The role of KRAS-G12C (Kr_G12C) is of special interest after the recent discovery and preclinical analyses of two different Kr_G12C covalent inhibitors (AMG-510, MRTX849).

METHODS

KRAS mutations were evaluated in formalin-fixed, paraffin-embedded tissue sections by a microfluidic-based multiplex polymerase chain reaction platform as a component of the previously published European Thoracic Oncology Platform Lungscape 003 Multiplex Mutation study, of clinically annotated, resected, stage I to III NSCLC. In this study, -Kr_G12C mutation prevalence and its association with clinicopathologic characteristics, molecular profiles, and postoperative patient outcome (overall survival, relapse-free survival, time-to-relapse) were explored.

RESULTS

KRAS gene was tested in 2055 Lungscape cases (adenocarcinomas: 1014 [49%]) with I or II or III stage respective distribution of 53% or 24% or 22% and median follow-up of 57 months. KRAS mutation prevalence in the adenocarcinoma cohort was 38.0% (95% confidence interval (CI): 35.0% to 41.0%), with Kr_G12C mutation representing 17.0% (95% CI: 14.7% to 19.4%). In the "histologic-subtype" cohort, Kr_G12C prevalence was 10.5% (95% CI: 9.2% to 11.9%). When adjusting for clinicopathologic characteristics, a significant negative prognostic effect of Kr_G12C presence versus other KRAS mutations or nonexistence of KRAS mutation was identified in the adenocarcinoma cohort alone and in the "histologic-subtype" cohort. For overall survival in adenocarcinomas, hazard ratio (HR)_{G12C versus other KRAS} is equal to 1.39 (95% CI: 1.03 to 1.89, p = 0.031) and HR_{G12C versus no KRAS} is equal to 1.32 (95% CI: 1.03 to 1.69, p = 0.028) (both also significant in the "histologic-subtype" cohort). For time-to-relapse, HR_{G12C versus other KRAS} is equal to 1.41 (95% CI: 1.03 to 1.92, p = 0.030). In addition, among all patients, for relapse-free survival, HR_{G12C versus no KRAS} is equal to 1.27 (95% CI: 1.04 to 1.54, p = 0.017).

CONCLUSIONS

In this large, clinically annotated stage I to III NSCLC cohort, the specific Kr_G12C mutation is significantly associated with poorer prognosis (adjusting for clinicopathologic characteristics) among adenocarcinomas and in unselected NSCLCs.

Differential CircRNA Expression Signatures May Serve as Potential Novel Biomarkers in Prostate Cancer

Circular RNAs (circRNAs), a recently discovered non-coding RNA, have a number of functions including the regulation of miRNA expression. They have been detected in a number of malignancies including prostate cancer (PCa). The differential expression pattern of circRNAs associated with PCa and androgen receptor (AR) status was investigated in this study. circRNA profiling was performed using a high throughout microarray assay on a panel of prostate cell lines, which consisted of normal, benign, and malignant cells (n = 9). circRNAs were more commonly significantly up-regulated (p < 0.05) than downregulated in malignant cell lines (n = 3,409) vs. benign cell lines (n = 2,949). In a grouped analysis based on AR status, there were 2,127 down-regulated circRNAs in androgen independent cell lines compared to 2,236 in androgen dependent cell lines, thus identifying a potential circRNA signature reflective of androgen dependency. Through a bioinformatics approach, the parental genes associated with the top 10 differentially expressed circRNAs were identified such as hsa_circ_0064644, whose predicted parental gene target is RBMS3, and hsa_circ_0060539, whose predicted gene target is SDC4. Furthermore, we identified three circRNAs associated with the parental gene Caprin1 (hsa_circ_0021652, hsa_circ_0000288, and hsa_circ_0021647). Other studies have shown the importance of Caprin1 in PCa cell survival and drug resistance. Given the modified circRNA expression signatures identified here, these hypothesis generating results suggest that circRNAs may serve as potential putative diagnostic and predictive markers in PCa. However, further validation studies are required to assess the true potential of these markers in the clinical setting.

Diagnostic Strategies for Treatment Selection in Advanced Prostate Cancer

Prostate Cancer (PCa) is a leading cause of morbidity and mortality among men worldwide. For most men with PCa, their disease will follow an indolent course. However, advanced PCa is associated with poor outcomes. There has been an advent of new therapeutic options with proven efficacy for advanced PCa in the last decade which has improved survival outcomes for men with this disease. Despite this, advanced PCa continues to be associated with a high rate of death. There is a lack of strong evidence guiding the timing and sequence of these novel treatment strategies. This paper focuses on a review of the strategies for diagnostic and the current evidence available for treatment selection in advanced PCa.

RET Fluorescence In Situ Hybridization Analysis Is a Sensitive but Highly Unspecific Screening Method for RET Fusions in Lung Cancer

INTRODUCTION

RET gene fusions are established oncogenic drivers in 1% of NSCLC. Accurate detection of advanced patients with RET fusions is essential to ensure optimal therapy choice. We investigated the performance of fluorescence in situ hybridization (FISH) as a diagnostic test for detecting functional RET fusions.

METHODS

Between January 2016 and November 2019, a total of 4873 patients with NSCLC were routinely screened for RET fusions using either FISH (n = 2858) or targeted RNA next-generation sequencing (NGS) (n = 2015). If sufficient material was available, positive cases were analyzed by both methods (n = 39) and multiple FISH assays (n = 17). In an independent cohort of 520 patients with NSCLC, whole-genome sequencing data were investigated for disruptive structural variations and functional fusions in the RET and compared with ALK and ROS1 loci.

RESULTS

FISH analysis revealed RET rearrangement in 48 of 2858 cases; of 30 rearranged cases double tested with NGS, only nine had a functional RET fusion. RNA NGS yielded RET fusions in 14 of 2015 cases; all nine cases double tested by FISH had RET locus rearrangement. Of these 18 verified RET fusion cases, 16 had a split signal and two a complex rearrangement by FISH. By whole-genome sequencing, the prevalence of functional fusions compared with all disruptive events was lower in the RET (4 of 9, 44%) than the ALK (27 of 34, 79%) and ROS1 (9 of 12, 75%) loci.

CONCLUSIONS

FISH is a sensitive but unspecific technique for RET screening, always requiring a confirmation using an orthogonal technique, owing to frequently occurring RET rearrangements not resulting in functional fusions in NSCLC.

Gene Expression Pathways in Prostate Tissue Associated with Vigorous Physical Activity in Prostate Cancer

BACKGROUND

Men engaged in high physical activity have lower risks of advanced and fatal prostate cancer. Mechanisms underlying this association are not well understood but may include systemic and tumor-specific effects. We investigated potential mechanisms linking physical activity and gene expression in prostate tissue from men with prostate cancer.

METHODS

We included a subset of 118 men in the Health Professionals Follow-up Study diagnosed with prostate cancer between 1986 and 2005 with whole-transcriptome gene expression profiling on tumor and adjacent normal prostate tissue and physical activity data. Long-term vigorous physical activity was self-reported as the average time spent engaged in various forms of recreational physical activity at baseline and biennially until prostate cancer diagnosis. Gene set enrichment analysis was performed among KEGG and Hallmark gene sets to identify pathways with differential expression based on vigorous physical activity.

RESULTS

In adjacent normal tissue, we identified 25 KEGG gene sets enriched (downregulated) in the highest compared with lowest quintile of vigorous physical activity at an FDR <0.10, including a number of cancer- and immune-related pathways. Although no gene sets reached statistical significance in tumor tissue, top gene sets differentially expressed included TGF beta, apoptosis, and p53 signaling pathways.

CONCLUSIONS

These findings suggest that physical activity may influence the tumor microenvironment. Future studies are needed to confirm these findings and further investigate potential mechanisms linking physical activity to lethal prostate cancer.

IMPACT

Identification of gene expression alterations in the prostate associated with physical activity can improve our understanding of prostate cancer etiology.

Vaping and lung cancer - A review of current data and recommendations

OBJECTIVES

Lung cancer is the most common cause of cancer mortality worldwide and, while tobacco smoke remains the primary cause, there is increasing concern that vaping and E-cigarette use may also increase lung cancer risk. This review concentrates on the current data, scholarship and active foci of research regarding potential cancer risk and oncogenic mechanisms of vaping and lung cancer.

MATERIALS AND METHODS

We performed a literature review of current and historical publications on lung cancer oncogenesis, vaping device/e-liquid contents and daughter products, molecular oncogenic mechanisms and the fundamental, potentially oncogenic, effects of electronic cigarette smoke/e-liquid products.

RESULTS

E-cigarette devices and vaping fluids demonstrably contain a series of both definite and probable oncogens including nicotine derivatives (e.g. nitrosnornicotine, nitrosamine ketone), polycyclic aromatic hydrocarbons, heavy metals (including organometal compounds) and aldehydes/other complex organic compounds. These arise both as constituents of the e-liquid (with many aldehydes and other complex organics used as flavourings) and as a result of pyrolysis/complex organic reactions in the electronic cigarette device (including unequivocal carcinogens such as formaldehyde - formed from pyrolysis of glycerol). Various studies demonstrate in vitro transforming and cytotoxic activity of these derivatives. E-cigarette device use has been significantly increasing - particularly amongst the younger cohort and non-smokers; thus, this is an area of significant concern for the future.

CONCLUSION

Although research remains somewhat equivocal, there is clear reason for concern regarding the potential oncogenicity of E-Cigarettes/E-Liquids with a strong basic and molecular science basis. Given lag times (extrapolating from tobacco smoke data) of perhaps 20 years, this may have significant future public health implications. Thus, the authors feel further study in this field is strongly warranted and consideration should be made for tighter control and regulation of these products.

Detection of MET Exon 14 Skipping Alterations in Lung Cancer Clinical Samples Using a PCR-Based Approach

The receptor tyrosine kinase (RTK) c-MET plays important roles in cancer, yet despite being frequently overexpressed, clinical responses to targeting this receptor have been limited in the clinical setting. A singular significant challenge has been the accurate identification of biomarkers for the selection of responsive patients. However, recently mutations which result in the loss of exon 14 (called METex14 skipping) have emerged as novel biomarkers in non-small cell lung carcinomas (NSCLC) to predict for responsiveness to targeted therapy with c-MET inhibitors. Currently, the diverse genomic alterations responsible for METex14 skipping pose a challenge for routine clinical diagnostic testing. Next generation sequencing (NGS) is the current gold standard for identifying the diverse mutations associated with METex14, but the cost for such a procedure remains to some degree prohibitive as often NGS is requested on a case-by-case basis, and many hospitals may not even have the capacity or resources to conduct NGS.However, PCR-based approaches to detect METex14 have been developed which can be conducted in most routine hospital laboratories and may therefore allow a cost-effective approach to pre-screen patients that may respond to c-MET inhibitors prior to conducting NGS, or until all patients will have NGS conducted as routine practise. In this chapter, we describe one such PCR-based approach for screening samples for the detection of METex14 in NSCLC.

Improvement in histological endpoints of MAFLD following a 12-week aerobic exercise intervention

BACKGROUND

Lifestyle interventions are the primary treatment for metabolic (dysfunction) associated fatty liver disease (MAFLD). However, the histological and cardiometabolic effects of aerobic exercise in MAFLD remain unclear.

AIMS

To assess the effects of a 12-week aerobic exercise intervention on histological and cardiometabolic endpoints in MAFLD.

METHODS

Patients with biopsy-confirmed MAFLD participated in a 12-week aerobic exercise intervention. Liver histology, cardiorespiratory fitness (estimated V̇O_2max ), physical activity, anthropometry and biochemical markers were assessed at baseline, intervention completion, and 12 and 52 weeks after intervention completion.

RESULTS

Twenty-four patients completed the exercise intervention (exercise group n = 16, control group n = 8). In the exercise group, 12 weeks of aerobic exercise reduced fibrosis and hepatocyte ballooning by one stage in 58% (P = 0.034) and 67% (P = 0.020) of patients, with no changes in steatosis (P = 1.000), lobular inflammation (P = 0.739) or NAFLD activity score (P = 0.172). Estimated V̇O_2max increased by 17% compared to the control group (P = 0.027) but this level of improvement was not maintained at 12 or 52 weeks after the intervention. Patients with fibrosis and ballooning improvement increased estimated V̇O_2max by 25% (P = 0.020) and 26% (P = 0.010), respectively. Anthropometric reductions including body mass (P = 0.038), waist circumference (P = 0.015) and fat mass (P = 0.007) were also observed, but no patient achieved 7%-10% weight loss.

CONCLUSION

This study highlights the potential benefits of a 12-week aerobic exercise intervention in improving histological endpoints of MAFLD. The development of strategies to ensure continued engagement in aerobic exercise in MAFLD are needed.

Family history of prostate cancer and the incidence of ERG- and phosphatase and tensin homolog-defined prostate cancer

Family history is among the strongest known risk factors for prostate cancer (PCa). Emerging data suggest molecular subtypes of PCa, including two somatic genetic aberrations: fusions of androgen-regulated promoters with ERG and, separately, phosphatase and tensin homolog (PTEN) loss. We examined associations between family history and incidence of these subtypes in 44,126 men from the prospective Health Professionals Follow-up Study. ERG and PTEN status were assessed by immunohistochemistry. Multivariable competing risks models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for associations between self-reported family history of PCa and molecular subtypes of disease. Thirteen percent of men had a positive family history of PCa at baseline. During a median follow-up of 18.5 years, 5,511 PCa cases were diagnosed. Among them, 888 were assayed for ERG status (47% ERG-positive) and 715 were assayed for PTEN loss (14% PTEN null). Family history was more strongly associated with risk of ERG-negative (HR: 2.15; 95% CI: 1.71-2.70) than ERG-positive (HR: 1.49; 95% CI: 1.13-1.95) disease (p_{heterogeneity} : 0.04). The strongest difference was among men with an affected father (HR_ERG-negative : 2.09; 95% CI: 1.64-2.66; HR_ERG-positive : 1.30; 95% CI: 0.96-1.76; p_{heterogeneity} : 0.01). Family history of PCa was positively associated with both PTEN null (HR: 2.10; 95% CI: 1.26-3.49) and PTEN intact (HR: 1.72; 95% CI: 1.39-2.13) PCa (p_{heterogeneity} : 0.47). Our results indicate that PCa family history may be positively associated with PCa in all ERG and PTEN subtypes, suggesting a role of genetic susceptibility in their development. It is possible that ERG-negative disease could be especially associated with positive family history.

Programmed death-ligand 1 expression influenced by tissue sample size. Scoring based on tissue microarrays' and cross-validation with resections, in patients with, stage I-III, non-small cell lung carcinoma of the European Thoracic Oncology Platform Lungscape cohort

PD-L1, as assessed by immunohistochemistry, is a predictive biomarker for immuno-oncology treatment in lung cancer. Different scoring methods have been used to assess its status, resulting in a wide range of positivity rates. We use the European Thoracic Oncology Platform Lungscape non-small cell lung carcinoma cohort to explore this issue. PD-L1 expression was assessed via immunohistochemistry on tissue microarrays (up to four cores per case), using the DAKO 28-8 immunohistochemistry assay, following a two-round external quality assessment procedure. All samples were analyzed under the same protocol. Cross-validation of scoring between tissue microarray and whole sections was performed in 10% randomly selected samples. Cutoff points considered: ≥1, 50 (primarily), and 25%. At the two external quality assessment rounds, tissue microarray scoring agreement rates between pathologists were: 73% and 81%. There were 2008 cases with valid immunohistochemistry tissue microarray results (50% all cores evaluable). Concordant cases at 1, 25, and 50% were: 85, 91, and 93%. Tissue microarray core results were identical for 70% of cases. Sensitivity of the tissue microarray method for 1, 25, and 50% was: 80, 78, and 79% (specificity: 90, 95, 98%). Complete agreement between tissue microarrays and whole sections was achieved for 60% of the cases. Highest sensitivity rates for 1% and 50% cutoffs were detected for higher number of cores. Underestimation of PD-L1 expression on small samples is more common than overestimation. We demonstrated that classification of PD-L1 on small biopsy samples does not represent the overall expression of PD-L1 in all non-small cell cancer carcinoma cases, although the majority of cases are 'correctly' classified. In future studies, sampling more and larger biopsies, recording the biopsy size and tumor load may permit further refinement, increasing predictive accuracy.

Statin Use Is Associated with Lower Risk of PTEN-Null and Lethal Prostate Cancer

PURPOSE

Statins are associated with lower risk of aggressive prostate cancer, but lethal prostate cancer is understudied and contributing mechanisms are unclear. We prospectively examined statins and lethal prostate cancer risk in the Health Professionals Follow-up Study (HPFS), tested associations with molecular subtypes, and integrated gene expression profiling to identify putative mechanisms.

EXPERIMENTAL DESIGN

Our study included 44,126 men cancer-free in 1990, followed for prostate cancer incidence through 2014, with statin use recorded on biennial questionnaires. We used multivariable Cox regression to examine associations between statins and prostate cancer risk overall, by measures of clinically significant disease, and by ERG and PTEN status. In an exploratory analysis, age-adjusted gene set enrichment analysis identified statin-associated pathways enriched in tumor and adjacent normal prostate tissue.

RESULTS

During 24 years of follow-up, 6,305 prostate cancers were diagnosed and 801 (13%) were lethal (metastatic at diagnosis or metastatic/fatal during follow-up). Relative to never/past use, current statin use was inversely associated with risk of lethal prostate cancer [HR, 0.76; 95% confidence interval (CI), 0.60-0.96] but not overall disease. We found a strong inverse association for risk of PTEN-null cancers (HR, 0.40; 95% CI, 0.19-0.87) but not PTEN-intact cancers (HR, 1.18; 95% CI, 0.95-1.48; P heterogeneity = 0.01). Associations did not differ by ERG. Inflammation and immune pathways were enriched in normal prostate tissue of statin ever (n = 10) versus never users (n = 103).

CONCLUSIONS

Molecular tumor classification identified PTEN and inflammation/immune activation as potential mechanisms linking statins with lower lethal prostate cancer risk. These findings support a potential causal association and could inform selection of relevant biomarkers for statin clinical trials.

Tumor protein expression of BRCA1 and development of lethal prostate cancer

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Background: DNA repair genes including BRCA1 are commonly altered in metastatic prostate tumors. However, mutations and copy number aberrations in these genes are rare in primary tumors. Instead, preliminary studies suggest that higher tumor expression of the BRCA1 protein may be associated with worse prognosis. Methods: We undertook a prospective study of tumor BRCA1 protein expression and lethal prostate cancer among men with clinically localized prostate cancer in the Health Professionals Follow-up Study. We performed immunohistochemical staining for BRCA1 on tumor tissue microarrays using a validated antibody and scored expression as positive or negative. We also assessed tumor proliferation by immunostaining for Ki67, angiogenesis by immunostaining for CD34, and apoptosis using a TUNEL assay. Proportional hazards regression was used to evaluate the association between BRCA1 protein expression and development of lethal prostate cancer (metastasis or cancer-specific death). Results: Ten percent of tumors (60 of 589) stained positive for the BRCA1 protein. BRCA1-positive tumors were characterized by higher Gleason scores, a higher proliferative index, and a higher apoptotic index. During a median follow-up of 14.3 years, 18 men (34%) in the BRCA1-positive group and 74 men (14%) in the BRCA1-negative group developed lethal prostate cancer. There was a strong positive association between BRCA1 protein expression and lethal prostate cancer in both unadjusted analyses (HR 2.71, 95% CI 1.73–4.26) and after adjusting for clinical factors (HR 2.00, 95% CI 1.26–3.18). The positive association with BRCA1 protein expression was also independent of proliferation index. Conclusions: Primary prostate tumors expressing the BRCA1 protein have a highly proliferative phenotype and are more likely to progress to lethal disease, independent of its higher proliferative index. Assessing tumor protein expression of BRCA1 may help elucidate the Janus-faced role of DNA repair pathways in prostate cancer progression.[Table: see text]

Evaluating liquid biopsies for methylomic profiling of prostate cancer

Background: Liquid biopsies offer significant potential for informing on cancer progression and therapeutic resistance via minimally invasive serial monitoring of genetic alterations. Although the cancer epigenome is a central driving force in most neoplasia, the accuracy of monitoring the tumor methylome using liquid biopsies remains relatively unknown. Objectives: to investigate how well two types of liquid biopsy (urine and blood) capture the prostate cancer methylome, and may thus serve as a non-invasive surrogate for studying the tumor epigenome. Methods: A cohort of four metastatic treatment naïve prostate cancer (PCa) patients was selected. Matched biopsy cores (tumor and histologically matched-normal), post-DRE, pre-biopsy urine, and peripheral blood plasma were available for each subject. DNA methylation was profiled utilizing the Infinium® MethylationEPIC BeadChip (Illumina) and analysed using the RnBeads software. Significantly (FDR adjusted P < 0.05) differentially methylated probes (DMPs) between tumor and MN were identified and examined in the liquids (done at a grouped and individual subject level). Results: DNA methylation analysis of urine and blood in men with metastatic PCa showed highly correlated patterns between the different liquid types (ρ = 0.93, P < 0.0001), with large contributions from non-tumor sources. DNA methylation profiles of liquids were more similar between subjects, than intra-individual liquid-tumor correlations. Overall, both urine and plasma are viable surrogates for tumor tissue biopsies, capturing up to 39.40% and 64.14% of tumor-specific methylation alterations, respectively. Conclusion: We conclude that both urine and blood plasma are easily accessible and sensitive biofluids for the study of PCa epigenomic alterations.

A randomized trial of exercise on quality of life in men with metastatic prostate cancer: The ExPeCT Trial

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Background: All patients living with cancer, including those with metastatic cancer, are encouraged to be physically active. This paper examines the feasibility of an aerobic exercise intervention for men with metastatic prostate cancer. Methods: ExPeCT (Exercise, Prostate Cancer and Circulating Tumour Cells), was a multi-centre randomised control trial for men living with metastatic prostate cancer. Participants were randomized to either control or exercise arms. Participants in the exercise arm completed six- months of prescribed aerobic exercise. Quality of life assessments were completed at baseline, at 3 months and at 6 months using a standardised questionnaire derived from the Harvard Health Professionals Follow-up study. Physical activity was measured using a self-administered physical activity questionnaire. Exercise adherence data was collected via Polar heart rate monitors, worn by the patient for every exercise session undertaken. Results: A total of 61 patients were included (69.4±7.3 yr, Body Mass Index 29.2±5.8 kg/m2). The median time since diagnosis was 34 months (IQR 7-54). A total of 35 (55%) of participants had >1 region affected by metastatic disease. A total of 54 (81%) of participants completed the 3 month assessment and 52 (78%) of the participants completed the 6 month assessment. Adherence to the supervised sessions was 83% (329 out of 396 sessions attended). Participants were adherent to both the intensity (82%) and duration (83%) of the prescribed exercise programme during class sessions. No adverse events were reported by participants enrolled in this study. There was no significant difference in physical activity levels, sedentary time or quality of life between either group at baseline, 3 months or 6 months. Systolic blood pressure was significantly lower in the exercise group when compared to the control group at 3 months (p=.008) and 6 months (p=.011). Conclusions: The exercise intervention was tolerated well by a group of patients with a high burden of metastatic prostate cancer however did not lead to change in physical activity levels or quality of life. This trial provides proof of principle evidence for future exercise studies involving this patient group. Clinical trial information: NCT02453139.

Circular RNAs are differentially expressed in prostate cancer and are potentially associated with resistance to enzalutamide

Most forms of castration-resistant prostate cancer (CRPC) are dependent on the androgen receptor (AR) for survival. While, enzalutamide provides a substantial survival benefit, it is not curative and many patients develop resistance to therapy. Although not yet fully understood, resistance can develop through a number of mechanisms, such as AR copy number gain, the generation of splice variants such as AR-V7 and mutations within the ligand binding domain (LBD) of the AR. circular RNAs (circRNAs) are a novel type of non-coding RNA, which can regulate the function of miRNA, and may play a key role in the development of drug resistance. circRNAs are highly resistant to degradation, are detectable in plasma and, therefore may serve a role as clinical biomarkers. In this study, AR-V7 expression was assessed in an isogenic model of enzalutamide resistance. The model consisted of age matched control cells and two sub-line clones displaying varied resistance to enzalutamide. circRNA profiling was performed on the panel using a high throughout microarray assay. Bioinformatic analysis identified a number of differentially expressed circRNAs and predicted five miRNA binding sites for each circRNA. miRNAs were stratified based on known associations with prostate cancer, and targets were validated using qPCR. Overall, circRNAs were more often down regulated in resistant cell lines compared with control (588 vs. 278). Of particular interest was hsa_circ_0004870, which was down-regulated in enzalutamide resistant cells (p ≤ 0.05, vs. sensitive cells), decreased in cells that highly express AR (p ≤ 0.01, vs. AR negative), and decreased in malignant cells (p ≤ 0.01, vs. benign). The associated parental gene was identified as RBM39, a member of the U2AF65 family of proteins. Both genes were down-regulated in resistant cells (p < 0.05, vs. sensitive cells). This is one of the first studies to profile and demonstrate discrete circRNA expression patterns in an enzalutamide resistant cell line model of prostate cancer. Our data suggests that hsa_circ_0004870, through RBM39, may play a critical role in the development of enzalutamide resistance in CRPC.

A retrospective cohort study of PD-L1 prevalence, molecular associations and clinical outcomes in patients with NSCLC: Results from the European Thoracic Oncology Platform (ETOP) Lungscape Project

INTRODUCTION

The PD-L1 biomarker is an important factor in selecting patients with non-small cell lung cancer for immunotherapy. While several reports suggest that PD-L1 positivity is linked to a poor prognosis, others suggest that PD-L1 positive status portends a good prognosis.

METHODS

PD-L1 positivity prevalence, assessed via immunohistochemistry (IHC) on tissue microarrays (TMAs), and its association with clinicopathological characteristics, molecular profiles and patient outcome- Relapse-free Survival (RFS), Time-to-Relapse (TTR) and Overall Survival (OS)- is explored in the ETOP Lungscape cohort of stage I-III non-small cell lung cancer (NSCLC). Tumors are considered positive if they have ≥1/5/25/50% neoplastic cell membrane staining.

RESULTS

PD-L1 expression was assessed in 2182 NSCLC cases (2008 evaluable, median follow-up 4.8 years, 54.6% still alive), from 15 ETOP centers. Adenocarcinomas represent 50.9% of the cohort (squamous cell: 42.4%). Former smokers are 53.7% (current: 31.6%, never: 10.5%). PD-L1 positivity prevalence is present in more than one third of the Lungscape cohort (1%/5% cut-offs). It doesn't differ between adenocarcinomas and squamous cell histologies, but is more frequently detected in higher stages, never smokers, larger tumors (1/5/25% cut-offs). With ≥1% cut-off it is significantly associated with IHC MET overexpression, expression of PTEN, EGFR and KRAS mutation (only for adenocarcinoma). Results for 5%, 25% and 50% cut-offs were similar, with MET being significantly associated with PD-L1 positivity both for AC (p < 0.001, 5%/25%/50% cut-offs) and SCC (p < 0.001, 5% & 50% cut-offs and p = 0.0017 for 25%). When adjusting for clinicopathological characteristics, a significant prognostic effect was identified in adenocarcinomas (adjusted p-values: 0.024/0.064/0.063 for RFS/TTR/OS 1% cut-off, analogous for 5%/25%, but not for 50%). Similar results obtained for the model including all histologies, but no effect was found for the squamous cell carcinomas.

CONCLUSION

PD-L1 positivity, when adjusted for clinicopathological characteristics, is associated with a better prognosis for non-metastatic adenocarcinoma patients.

An updated analysis evaluating skeletal related events (SREs) in CTRIAL-IE 13-21: Phase II trial of radium-223 (R223) in combination with enzalutamide (ENZA) for patients (pts) with metastatic castration-resistant prostate cancer (mCRPC)

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Background: This phase II single arm study, previously reported on the safety and tolerability of the combination of R223 and ENZA in pts with mCRPC. R223 in combination with ENZA was well tolerated with acceptable safety and toxicity profiles. Methods: This study enrolled pts with mCRPC to bone with or without visceral/lymph node involvement progressing on ADT. Pts received 6 cycles of R223 (55 kBq/kg IV Q4W) in combination with ENZA (160mg/day), followed by ENZA alone. Bone health agents were initiated as per treating clinician choice. SREs were defined as: a pathologic fracture, spinal cord compression (SCC), necessity for external beam radiation (EBRT) or surgery to bone. SREs during the combination period and after completion of R223 are reported here. An unplanned retrospective analysis of all scans performed on each patient for any fracture was performed and is included. Results: From July 2015 to July 2017, 45 pts were enrolled. 42 pts (93.3%) received all 6 cycles of combination therapy. 16 pts (35.5%) remain on ENZA alone. In total, 6 pts (13.3%) had SREs. 4 developed pathological fractures (femur = 1, vertebrae = 3) while 3 had EBRT for pain. Of these 6 pts, 2 developed SCC requiring EBRT. The average time from starting R223 to SRE was 615 days. 2/6 pts were not receiving bone protection. One pt who developed a pathological fracture has subsequently died related to progressive disease (time to death = 292 days). In the retrospective analysis, 4 pts (8.8%) developed fractures which were associated with a history of trauma (radius = 1, tibia = 1 ribs = 2). 11 pts (24.4%) developed asymptomatic insufficiency fractures (ankle = 1, femur = 1, sacrum = 2, vertebrae = 4, ribs = 4). The average time to insufficiency fracture was 354 days. No interventions were required. The majority of pts (75.5%) on the study were receiving bone health agents. Conclusions: SREs were in keeping with previously published data. In an unplanned retrospective analysis, there was a higher incidence of asymptomatic insufficiency fractures in this cohort of patients, however no interventions were required. Clinical trial information: NCT02225704.

The effect of a structured exercise intervention on CTCs and platelet cloaking in patients with metastatic prostate cancer

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Background: Physical activity has been described as an effective adjunct for improving quality of life in patients with metastatic prostate cancer (PrCa). Circulating tumor cells (CTCs) are a morphologically distinct set of cancer cells, involved in disease progression. Platelet cloaking, the surrounding and subsequent attachment of platelets to CTCs, has been proposed as effective in aiding extravasation, thus enhancing metastatic spread. The ExPeCT (Exercise, Prostate Cancer and Circulating Tumor Cells) trial aimed to examine the impact of a structured exercise intervention on the mechanisms of metastasis, including CTC cloaking, in patients with metastatic PrCa. Methods: ExPeCT was a multi-center, randomized trial for patients with metastatic PrCa (n=61). Participants were randomized to either control or exercise arms. Participants in the exercise arm (n=29) completed six months of prescribed aerobic exercise. Whole blood was collected for all participants at baseline (T0), three months (T3) and six months (T6), and analyzed for the presence of CTCs, CTC clusters and platelet cloaking. Results: No significant difference in CTC number between the exercise and control arms was observed (p=0.2630), however significant alterations in CTC number were observed within group over time (p<0.001). Platelet cloaking was modelled as a binary response (presence/absence). A trend towards higher levels of platelet cloaking in the control group was observed (p=0.1005). Further, all findings were compared to a range of clinical variables. CTC clusters were positively correlated with PSA levels (p=0.0393) and a positive correlation between CTC number and white blood cell count (p<0.001) was determined. Conclusions: No significant relationship between CTCs and physical activity was observed, however the exercise program was well tolerated by ExPeCT participants. This study has, for the first time, shown platelet cloaking of CTCs in metastatic PrCa, in addition to a significant positive correlation between CTCs and white blood cells. These findings provide critical insight into immune crosstalk and the metastatic cascade in metastatic PrCa. Clinical trial information: NCT02453139.

Cost-Efficient and Easy to Perform PCR-Based Assay to Identify Met Exon 14 Skipping in Formalin-Fixed Paraffin-Embedded (FFPE) Non-Small Cell Lung Cancer (NSCLC) Samples

MET is a receptor tyrosine kinase (RTK) that plays important roles in carcinogenesis. Despite being frequently overexpressed in cancer, clinical responses to targeting this receptor have been limited. Recently novel splicing mutations involving the loss of exon 14 (called METex14 skipping) have emerged as potential biomarkers to predict for responsiveness to targeted therapies with Met inhibitors in non-small cell lung cancer (NSCLC). Currently, the diverse genomic alterations responsible for METex14 skipping pose a challenge for routine clinical diagnostic testing. In this report, we examine three different methodologies to detect METex14 and assess their potential utility for use as a diagnostic assay for both the identification of METex14 and intra-tumoural distribution in NSCLC.

A Prospective Study of the Association between Physical Activity and Risk of Prostate Cancer Defined by Clinical Features and TMPRSS2:ERG

BACKGROUND

Growing evidence shows that clinical and molecular subtypes of prostate cancer (PCa) have specific risk factors. Observational studies suggest that physical activity may lower the risk of aggressive PCa. To our knowledge, the association between physical activity and PCa defined by TMPRSS2:ERG has not been evaluated.

OBJECTIVE

To prospectively examine the association between physical activity and risk of PCa defined by clinical features and TMPRSS2:ERG.

DESIGN, SETTING, AND PARTICIPANTS

We studied 49160 men aged 40-75 yr in the Health Professionals Follow-up Study from 1986 to 2012. Data was collected at baseline and every 2 yr with >90% follow-up. Total and vigorous physical activity were measured in metabolic equivalent of task (MET)-h/wk.

OUTCOME MEASURES AND STATISTICAL ANALYSIS

Advanced PCa was defined as stage T3b, T4, N1, or M1 at diagnosis and lethal PCa as distant metastases or death due to disease over follow-up. Presence of TMPRSS2:ERG was estimated by immunohistochemistry of ERG protein expression. Cox proportional hazards models were used to obtain multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) for incidence of subtype-specific PCa.

RESULTS AND LIMITATIONS

During 26 yr of follow-up, 6411 developed PCa overall and 888 developed lethal disease. There were no significant associations between total physical activity and risk of PCa in the overall cohort. In multivariable-adjusted models, men in the highest quintile of vigorous activity had a significant 30% lower risk of advanced PCa (HR: 0.70, 95% CI: 0.53-0.92) and 25% lower risk of lethal PCa (HR: 0.75, 95% CI: 0.59-0.94) than men in the lowest quintile of vigorous activity. The association was independent of screening history. Vigorous activity was not associated with total PCa in the overall cohort but was inversely associated among highly screened men (top vs bottom quintile, HR: 0.83, 95% CI: 0.70-0.97). Of all cases, 945 were assayed for ERG (48% ERG-positive). Men with higher vigorous activity had a lower risk of ERG-positive PCa (top vs bottom quintile, HR: 0.71, 95% CI: 0.52-0.97). There was no significant association with the risk of ERG-negative disease (p heterogeneity=0.09).

CONCLUSIONS

Our study confirms that vigorous physical activity is associated with lower risk of advanced and lethal PCa and provides novel evidence for a lower risk of TMPRSS2:ERG-positive disease.

PATIENT SUMMARY

The identification of modifiable lifestyle factors for prevention of clinically important prostate cancer (PCa) is needed. In this report, we compared risk of PCa in men with different levels of physical activity. Men with higher vigorous activity had a lower risk of developing advanced and lethal PCa and PCa with the common TMPRSS2:ERG gene fusion.