Lisa Moris

Advances in stem cell research for the treatment of male sexual dysfunctions

Purpose of review To summarize recent literature on basic stem cell research in erectile dysfunction in cavernous nerve injury, aging, diabetes, and Peyronies disease and to provide a perspective on clinical translation of these cellular therapies. Recent findings Stem cell research has been concentrated on mesenchymal stem (stromal) cells from bone marrow and adipose tissue. Application of both cell types has produced positive effects on erectile function in various animal models of erectile dysfunction. In acute animal models, such as cavernous nerve injury-induced erectile dysfunction and chemically induced Peyronies disease, engraftment and differentiation have not been observed, and stem cells are believed to interact with the host tissue in a paracrine fashion, whereas in chronic disease models some evidence suggests both engraftment and paracrine factors may support improved function. Clinical trials are now investigating therapeutic efficacy of cellular therapy, whereas the first safety studies in humans have recently been published. Summary Evidence from preclinical studies has established stem cells as a potential curative treatment for erectile dysfunction and early phase clinical trials are currently performed.

Impact of Lymph Node Burden on Survival of High-risk Prostate Cancer Patients Following Radical Prostatectomy and Pelvic Lymph Node Dissection

Aim To determine the impact of the extent of lymph node invasion (LNI) on long-term oncological outcomes after radical prostatectomy (RP). Material and methods In this retrospective study, we examined the data of 1,249 high-risk, non-metastatic PCa patients treated with RP and pelvic lymph node dissection (PLND) between 1989 and 2011 at eight different tertiary institutions. We fitted univariate and multivariate Cox models to assess independent predictors of cancer-specific survival (CSS) and overall survival (OS). The number of positive lymph node (LN) was dichotomized according to the most informative cutoff predicting CSS. Kaplan–Meier curves assessed CSS and OS rates. Only patients with at least 10 LNs removed at PLND were included. This cutoff was chosen as a surrogate for a well performed PNLD. Results Mean age was 65 years (median: 66, IQR 60–70). Positive surgical margins were present in 53.7% (n = 671). Final Gleason score (GS) was 2–6 in 12.7% (n = 158), 7 in 52% (n = 649), and 8–10 in 35.4% (n = 442). The median number of LNs removed during PLND was 15 (IQR 12–17). Of all patients, 1,128 (90.3%) had 0–3 positive LNs, while 126 (9.7%) had ≥4 positive LNs. Patients with 0–3 positive LNs had significantly better CSS outcome at 10-year follow-up compared to patients with ≥4 positive LNs (87 vs. 50%; p < 0.0001). Similar results were obtained for OS, with a 72 vs. 37% (p < 0.0001) survival at 10 years for patients with 0–3 vs. ≥4 positive LNs, respectively. At multivariate analysis, final GS of 8–10, salvage ADT therapy, and ≥4 (vs. <4) positive LNs were predictors of worse CSS and OS. Pathological stage pT4 was an additional predictor of worse CSS. Conclusion Four or more positive LNs, pathological stage pT4, and final GS of 8–10 represent independent predictors for worse CSS in patients with high-risk PCa. Primary tumor biology remains a strong driver of tumor progression and patients having ≥4 positive LNs could be considered an enriched patient group in which novel treatment strategies should be studied.

Tumor Volume and Clinical Failure in High-Risk Prostate Cancer Patients Treated With Radical Prostatectomy.

To identify the most significant cut‐off of tumor volume (TV) for prediction of clinical failure (CF) among high‐risk prostate cancer (hPCa) patients.

The role of TET-mediated DNA hydroxymethylation in prostate cancer

Ten-eleven translocation (TET) proteins are recently characterized dioxygenases that regulate demethylation by oxidizing 5-methylcytosine to 5-hydroxymethylcytosine and further derivatives. The recent finding that 5hmC is also a stable and independent epigenetic modification indicates that these proteins play an important role in diverse physiological and pathological processes such as neural and tumor development. Both the genomic distribution of (hydroxy)methylation and the expression and activity of TET proteins are dysregulated in a wide range of cancers including prostate cancer. Up to now it is still unknown how changes in TET and 5(h)mC profiles are related to the pathogenesis of prostate cancer. In this review, we explore recent advances in the current understanding of how TET expression and function are regulated in development and cancer. Furthermore, we look at the impact on 5hmC in prostate cancer and the potential underlying mechanisms. Finally, we tried to summarize the latest techniques for detecting and quantifying global and locus-specific 5hmC levels of genomic DNA.

The survival impact of neoadjuvant hormonal therapy before radical prostatectomy for treatment of high-risk prostate cancer.

Background:Several randomized controlled trials assessed the outcomes of patients treated with neoadjuvant hormonal therapy (NHT) before radical prostatectomy (RP). The majority of them included mainly low and intermediate risk prostate cancer (PCa) without specifically assessing PCa-related death (PCRD). Thus, there is a lack of knowledge regarding a possible effect of NHT on PCRD in the high-risk PCa population. We aimed to analyze the effect of NHT on PCRD in a multicenter high-risk PCa population treated with RP, using a propensity-score adjustment.Methods:This is a retrospective multi-institutional study including patients with high-risk PCa defined as: clinical stage T3–4, PSA >20 ng ml−1 or biopsy Gleason score 8–10. We compared PCRD between RP and NHT+RP using competing risks analysis. Correction for group differences was performed by propensity-score adjustment.Results:After application of the inclusion/exclusion criteria, 1573 patients remained for analysis; 1170 patients received RP and 403 NHT+RP. Median follow-up was 56 months (interquartile range 29–88). Eighty-six patients died of PCa and 106 of other causes. NHT decreased the risk of PCRD (hazard ratio (HR) 0.5; 95% confidence interval (CI) 0.32–0.80; P=0.0014). An interaction effect between NHT and radiotherapy (RT) was observed (HR 0.3; 95% CI 0.21–0.43; P<0.0008). More specifically, of patients who received adjuvant RT, those who underwent NHT+RP had decreased PCRD rates (2.3% at 5 year) compared to RP (7.5% at 5 year). The retrospective design and lack of specific information about NHT are possible limitations.Conclusions:In this propensity-score adjusted analysis from a large high-risk PCa population, NHT before surgery significantly decreased PCRD. This effect appeared to be mainly driven by the early addition of RT post-surgery. The specific sequence of NHT+RP and adjuvant RT merits further study in the high-risk PCa population.

Prostate cancer: The influence of steroid metabolism on CYP17A1 inhibitor activity

Galeterone is a steroid 17-α-hydroxylase/17,20 lyase and androgen receptor antagonist intended for patients with prostate cancer. Similar to abiraterone, galeterone has a steroid scaffold structure and mimics natural ligands; thus, these agents are metabolized by the same enzymes that synthesize or degrade naturally occurring steroids, which can result in attenuated efficacy.

Treatment-induced changes in the androgen receptor axis: Liquid biopsies as diagnostic/prognostic tools for prostate cancer

Prostate cancer progression and treatment relapse is associated with changes in the androgen receptor axis, and analysis of alternations of androgen receptor signaling is valuable for prognostics and treatment optimization. The profile of androgen receptor axis is currently obtained from biopsy specimens, which are not always easy to obtain. Moreover, the information acquired only provides a snapshot of the tumor biology, with strict spatial and temporal limitations. On the other hand, circulation is easily accessible source of both circulating tumor cells and circulating tumor DNA, which can be sampled at numerous time points. This Review will explore the potential use of androgen receptor axis alternations detectable in the blood in therapeutic decision-making and precision medicine for advancing metastatic castration-resistant prostate cancer.

Abstract B075: The role of TET1 and hydroxymethylation in high-risk prostate cancer

The Ten-eleven translocation (TET) proteins are dioxygenases that catalyze the oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) as part of the DNA demethylation pathway. Gene silencing through cytosine methylation contributes to cancer formation, but how hydroxymethylation affects gene expression is largely unknown. In this work, TET1 and genomic hydroxymethylation were investigated in a high-risk prostate cancer cohort for which exome sequencing data are available (1). Immunohistochemical analysis of tumor versus nontumor prostate biopsies from high-risk prostate cancer showed a strong reduction of genome-wide 5hmC and milder but still significant reduction of 5mC levels in prostate cancer tissue compared to control tissue. Copy number analysis of high-risk prostate cancer showed a loss of the TET1 genomic region in 6 out of 39 samples of our cohort. As expected, the mRNA levels of TET1 were decreased in these tumor samples. Recently, an alternative promoter of TET1 was discovered. This promoter generates a novel isoform lacking the CXXC-domain, which is called TET1ALT (2). We therefore performed functional analyses of the two TET1 promoters in prostate cancer cells. Interestingly, the promoter controlling expression of the endogenous full-length TET1 is less active in prostate cancer cell line PC-3, while the alternative promoter generating TET1ALT is more active in these cells. This is shown by luciferase constructs driven by the two promoter regions. In conclusion, our findings indicate that there is a drop in (hydroxy)methylation levels in high-risk prostate cancer that correlates with decreased TET1 expression levels and in some cases by a copy number loss of TET1. We are currently working on a more detailed analysis of TET1 promoter usage and control. This will unravel the regulation of hydroxymethylation in prostate cancer, which is crucial for the understanding of prostate cancer development and progression. References: 1. Spans L, Van den Broeck T, Smeets E, et al. Genomic and epigenomic analysis of high-risk prostate cancer reveals changes in hydroxymethylation and TET1. Oncotarget 2016;7(17):24326-38. 2. Good CR, Madzo J, Patel B, et al. A novel isoform of TET1 that lacks a CXXC domain is overexpressed in cancer. Nucleic Acids Res 2017;45(14):8269-81. Citation Format: Elien Smeets, Lien Spans, Stefan Prekovic, Thomas Van den Broeck, Lisa Moris, Thomas Gevaert, Christine Helsen, Steven Joniau, Frank Claessens. The role of TET1 and hydroxymethylation in high-risk prostate cancer [abstract]. In: Proceedings of the AACR Special Conference: Prostate Cancer: Advances in Basic, Translational, and Clinical Research; 2017 Dec 2-5; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(16 Suppl):Abstract nr B075.

Abstract B065: Genomic analysis of localized prostate cancer identifies AZIN1 as driver of metastatic progression

High-risk PCa (HRPCa) remains very heterogeneous with an unacceptable variation in patient outcome after radical prostatectomy, with cancer-specific mortality rates ranging from 4.6% to 20.3% at 10 years’ follow-up. Clearly, we need a better understanding of the tumor biology to enhance the subclassification, enable the identification of lethal PCa, and eventually allow a more precise decision-making regarding treatment. We created a matched case-control study of two clinically identical HRPCa patient groups, both treated with radical prostatectomy but where one developed metastatic recurrence (n=19) and the other did not (n=25), despite very-long-term follow-up. The integrated analysis of copy number aberrations and transcriptome analysis highlighted a focal amplification of 8q22.3 in the metastatic group, associated with a higher expression of antizyme inhibitor 1 (AZIN1) in our cohort. This association of high AZIN1 levels with the metastatic HRPCa phenotype suggests a role for AZIN1 as possible predictor and/or target for metastatic HRPCa. AZIN1 is one of the regulators of the polyamine synthesis, which play a central role in many cellular processes. Our in vitro analyses confirmed that modulation of AZIN1 expression determines both growth and migratory potential of prostate cancer cells. Future experiments are planned to confirm these data in the in vivo setting. RNA sequencing after knockdown of AZIN1 in PCa cells revealed several transcriptional programs that are activated/deactivated upon AZIN1 knockdown. This showed among others a significant upregulation of genes involved in extracellular matrix composition, including genes encoding for subunits of the collagen IV, which is an integral part of the basement membrane. Ongoing experiments focus on identifying the mechanism by which AZIN1 regulates collagen IV expression. Citation Format: Thomas Van den Broeck, Lisa Moris, Thomas Gevaert, Elien Smeets, Stefan Prekovic, Christine Helsen, Hendrik van Poppel, Wouter Everaerts, Christine Buerki, Elai Davicioni, Steven Joniau, Frank Claessens. Genomic analysis of localized prostate cancer identifies AZIN1 as driver of metastatic progression [abstract]. In: Proceedings of the AACR Special Conference: Prostate Cancer: Advances in Basic, Translational, and Clinical Research; 2017 Dec 2-5; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(16 Suppl):Abstract nr B065.

Comparison of Functional Outcome after Extended versus Super-Extended Pelvic Lymph Node Dissection during Radical Prostatectomy in High-Risk Localized Prostate Cancer

Background Urinary continence and erectile function (EF) are best preserved when meticulous dissection of prostate and nerve sparing technique are used during radical prostatectomy (RP). However, extent of lymph node dissection (LND) may also adversely affect functional results. Objective To determine whether performing a super-extended LND (seLND) has a significant effect on recovery of urinary continence and EF after RP. Design, setting, and participants All patients who underwent RP from January 2007 until December 2013 were handed questionnaires assessing continence and EF. All patients in whom at least an extended LND (eLND) was performed were selected. This search yielded 526 patients. 172 of these patients had filed out 2 or more questionnaires and were included in our analysis. Outcome measurements and statistical analysis All questionnaires were reviewed. We used Kaplan–Meier analyses and multivariate Cox analysis to assess the difference in recovery of continence and EF over time for eLND/seLND. Primary endpoints were full recovery of continence (no loss of urine) and full recovery of EF (successful intercourse possible). Patients who did not reach the endpoint when the last questionnaire was filled out were censored at that time. Median follow-up was 12.43 months for continence, and 18.97 months for EF. Results and limitations Patients undergoing seLND have a lower chance of regaining both urinary continence [hazard ratio (HR) 0.59, 95% CI 0.39–0.90, p = 0.026] and EF (HR 0.28, 95% CI 0.13–0.57, p = 0.009). Age at surgery had a significant influence on both continence and EF in multivariate analysis. Major limitation of the study was that no formal preoperative assessment of continence and potency was done. Conclusion Extending the LND template beyond the eLND template may cause at least a significant delay in recovery of urinary continence and leads to less recovery of EF.