Publications by authors named "Martin E Gleave"

289 Publications

CKB inhibits epithelial-mesenchymal transition and prostate cancer progression by sequestering and inhibiting AKT activation.

Neoplasia 2021 11 24;23(11):1147-1165. Epub 2021 Oct 24.

Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA; University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA. Electronic address:

Epithelial-mesenchymal transition (EMT) contributes to tumor invasion, metastasis and drug resistance. AKT activation is key in a number of cellular processes. While many positive regulators for either EMT or AKT activation have been reported, few negative regulators are established. Through kinase cDNA screen, we identified brain-type creatine kinase (CKB or BCK) as a potent suppressor for both. As a ubiquitously expressed kinase in normal tissues, CKB is significantly downregulated in several solid cancer types. Lower CKB expression is significantly associated with worse prognosis. Phenotypically, CKB overexpression suppresses, while its silencing promotes, EMT and cell migration, xenograft tumor growth and metastasis of prostate cancer cells. AKT activation is one of the most prominent signaling events upon CKB silencing in prostate cancer cells, which is in line with prostate cancer TCGA data. EMT enhanced by CKB silencing is abolished by AKT inhibition. Mechanistically, CKB interacts with AKT and sequestrates it from activation by mTOR. We further elucidated that an 84aa fragment at C-terminus of CKB protein interacts with AKT's PH domain. Ectopic expression of the 84aa CKB fragment inhibits AKT activation, EMT and cell proliferation. Interestingly, molecular dynamics simulation on crystal structures of AKT and CKB independently demonstrates that AKT's PH domain and CKB's 84aa fragment establish their major interaction interface. In summary, we have discovered CKB as a negative regulator of EMT and AKT activation, revealing a new mode of their regulation . We have also demonstrated that CKB downregulation is a poor prognosticator, which is sufficient to promote prostate cancer progression.
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http://dx.doi.org/10.1016/j.neo.2021.09.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8551525PMC
November 2021

Development of 2-(5,6,7-Trifluoro-1-Indol-3-yl)-quinoline-5-carboxamide as a Potent, Selective, and Orally Available Inhibitor of Human Androgen Receptor Targeting Its Binding Function-3 for the Treatment of Castration-Resistant Prostate Cancer.

J Med Chem 2021 Oct 18;64(20):14968-14982. Epub 2021 Oct 18.

Vancouver Prostate Centre, University of British Columbia, 2660 Oak Street, Vancouver, British Columbia V6H 3Z6, Canada.

Prostate cancer (PCa) patients undergoing androgen deprivation therapy almost invariably develop castration-resistant prostate cancer (CRPC). Targeting the androgen receptor (AR) Binding Function-3 (BF3) site offers a promising option to treat CRPC. However, BF3 inhibitors have been limited by poor potency or inadequate metabolic stability. Through extensive medicinal chemistry, molecular modeling, and biochemistry, we identified 2-(5,6,7-trifluoro-1-Indol-3-yl)-quinoline-5-carboxamide (VPC-13789), a potent AR BF3 antagonist with markedly improved pharmacokinetic properties. We demonstrate that VPC-13789 suppresses AR-mediated transcription, chromatin binding, and recruitment of coregulatory proteins. This novel AR antagonist selectively reduces the growth of both androgen-dependent and enzalutamide-resistant PCa cell lines. Having demonstrated efficacy, we developed an orally bioavailable prodrug that reduced PSA production and tumor volume in animal models of CRPC with no observed toxicity. VPC-13789 is a potent, selective, and orally bioavailable antiandrogen with a distinct mode of action that has a potential as novel CRPC therapeutics.
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http://dx.doi.org/10.1021/acs.jmedchem.1c00681DOI Listing
October 2021

Treatment in the absence of disease reclassification among men on active surveillance for prostate cancer.

Cancer 2021 Sep 13. Epub 2021 Sep 13.

Department of Urology, University of Washington, Seattle, Washington.

Background: Maintaining men on active surveillance for prostate cancer can be challenging. Although most men who eventually undergo treatment have experienced clinical progression, a smaller subset elects treatment in the absence of disease reclassification. This study sought to understand factors associated with treatment in a large, contemporary, prospective cohort.

Methods: This study identified 1789 men in the Canary Prostate Cancer Active Surveillance Study cohort enrolled as of 2020 with a median follow-up of 5.6 years. Clinical and demographic data as well as information on patient-reported quality of life and urinary symptoms were used in multivariable Cox proportional hazards regression models to identify factors associated with the time to treatment RESULTS: Within 4 years of their diagnosis, 33% of men (95% confidence interval [CI], 30%-35%) underwent treatment, and 10% (95% CI, 9%-12%) were treated in the absence of reclassification. The most significant factor associated with any treatment was an increasing Gleason grade group (adjusted hazard ratio [aHR], 14.5; 95% CI, 11.7-17.9). Urinary quality-of-life scores were associated with treatment without reclassification (aHR comparing "mostly dissatisfied/terrible" with "pleased/mixed," 2.65; 95% CI, 1.54-4.59). In a subset analysis (n = 692), married men, compared with single men, were more likely to undergo treatment in the absence of reclassification (aHR, 2.63; 95% CI, 1.04-6.66).

Conclusions: A substantial number of men with prostate cancer undergo treatment in the absence of clinical changes in their cancers, and quality-of-life changes and marital status may be important factors in these decisions.

Lay Summary: This analysis of men on active surveillance for prostate cancer shows that approximately 1 in 10 men will decide to be treated within 4 years of their diagnosis even if their cancer is stable. These choices may be related in part to quality-or-life or spousal concerns.
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http://dx.doi.org/10.1002/cncr.33911DOI Listing
September 2021

Development of an Androgen Receptor Inhibitor Targeting the N-Terminal Domain of Androgen Receptor for Treatment of Castration Resistant Prostate Cancer.

Cancers (Basel) 2021 Jul 12;13(14). Epub 2021 Jul 12.

Vancouver Prostate Centre, University of British Columbia, 2660 Oak Street, Vancouver, BC V6H 3Z6, Canada.

Prostate cancer patients undergoing androgen deprivation therapy almost invariably develop castration-resistant prostate cancer. Resistance can occur when mutations in the androgen receptor (AR) render anti-androgen drugs ineffective or through the expression of constitutively active splice variants lacking the androgen binding domain entirely (e.g., ARV7). In this study, we are reporting the discovery of a novel AR-NTD covalent inhibitor 1-chloro-3-[(5-([(2S)-3-chloro-2-hydroxypropyl]amino)naphthalen-1-yl)amino]propan-2-ol (VPC-220010) targeting the AR-N-terminal Domain (AR-NTD). VPC-220010 inhibits AR-mediated transcription of full length and truncated variant ARV7, downregulates AR response genes, and selectively reduces the growth of both full-length AR- and truncated AR-dependent prostate cancer cell lines. We show that VPC-220010 disrupts interactions between AR and known coactivators and coregulatory proteins, such as CHD4, FOXA1, ZMIZ1, and several SWI/SNF complex proteins. Taken together, our data suggest that VPC-220010 is a promising small molecule that can be further optimized into effective AR-NTD inhibitor for the treatment of CRPC.
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http://dx.doi.org/10.3390/cancers13143488DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8304761PMC
July 2021

Evaluation of Darolutamide (ODM201) Efficiency on Androgen Receptor Mutants Reported to Date in Prostate Cancer Patients.

Cancers (Basel) 2021 Jun 11;13(12). Epub 2021 Jun 11.

Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, 2660 Oak St., Vancouver, BC V6H 3Z6, Canada.

Resistance to drug treatments is common in prostate cancer (PCa), and the gain-of-function mutations in human androgen receptor (AR) represent one of the most dominant drivers of progression to resistance to AR pathway inhibitors (ARPI). Previously, we evaluated the in vitro response of 24 AR mutations, identified in men with castration-resistant PCa, to five AR antagonists. In the current work, we evaluated 44 additional PCa-associated AR mutants, reported in the literature, and thus expanded the study of the effect of darolutamide to a total of 68 AR mutants. Unlike other AR antagonists, we demonstrate that darolutamide exhibits consistent efficiency against all characterized gain-of-function mutations in a full-length AR. Additionally, the response of the AR mutants to clinically used bicalutamide and enzalutamide, as well as to major endogenous steroids (DHT, estradiol, progesterone and hydrocortisone), was also investigated. As genomic profiling of PCa patients becomes increasingly feasible, the developed "AR functional encyclopedia" could provide decision-makers with a tool to guide the treatment choice for PCa patients based on their AR mutation status.
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http://dx.doi.org/10.3390/cancers13122939DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8230763PMC
June 2021

Evolution of Castration-Resistant Prostate Cancer in ctDNA during Sequential Androgen Receptor Pathway Inhibition.

Clin Cancer Res 2021 Aug 3;27(16):4610-4623. Epub 2021 Jun 3.

Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, British Columbia, Canada.

Purpose: Cross-resistance renders multiple lines of androgen receptor (AR) signaling inhibitors increasingly futile in metastatic castration-resistant prostate cancer (mCRPC). We sought to determine acquired genomic contributors to cross-resistance.

Experimental Design: We collected 458 serial plasma cell-free DNA samples at baseline and progression timepoints from 202 patients with mCRPC receiving sequential AR signaling inhibitors (abiraterone and enzalutamide) in a randomized phase II clinical trial (NCT02125357). We utilized deep targeted and whole-exome sequencing to compare baseline and posttreatment somatic genomic profiles in circulating tumor DNA (ctDNA).

Results: Patient ctDNA abundance was correlated across plasma collections and independently prognostic for sequential therapy response and overall survival. Most driver alterations in established prostate cancer genes were consistently detected in ctDNA over time. However, shifts in somatic populations after treatment were identified in 53% of patients, particularly after strong treatment responses. Treatment-associated changes converged upon the gene, with an average 50% increase in copy number, changes in mutation frequencies, and a 2.5-fold increase in the proportion of patients carrying AR ligand binding domain truncating rearrangements.

Conclusions: Our data show that the dominant genotype continues to evolve during sequential lines of AR inhibition and drives acquired resistance in patients with mCRPC.
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http://dx.doi.org/10.1158/1078-0432.CCR-21-1625DOI Listing
August 2021

SLFN5 Regulates LAT1-Mediated mTOR Activation in Castration-Resistant Prostate Cancer.

Cancer Res 2021 Jul 13;81(13):3664-3678. Epub 2021 May 13.

CRUK Beatson Institute, Garscube Estate, Glasgow, United Kingdom.

Androgen deprivation therapy (ADT) is the standard of care for treatment of nonresectable prostate cancer. Despite high treatment efficiency, most patients ultimately develop lethal castration-resistant prostate cancer (CRPC). In this study, we performed a comparative proteomic analysis of three , androgen receptor (AR)-responsive orthograft models of matched hormone-naïve prostate cancer and CRPC. Differential proteomic analysis revealed that distinct molecular mechanisms, including amino acid (AA) and fatty acid metabolism, are involved in the response to ADT in the different models. Despite this heterogeneity, Schlafen family member 5 (SLFN5) was identified as an AR-regulated protein in CRPC. SLFN5 expression was high in CRPC tumors and correlated with poor patient outcome. depletion strongly impaired tumor growth in castrated conditions. Mechanistically, SLFN5 interacted with ATF4 and regulated the expression of LAT1, an essential AA transporter. Consequently, depletion in CRPC cells decreased intracellular levels of essential AA and impaired mTORC1 signaling in a LAT1-dependent manner. These results confirm that these orthograft models recapitulate the high degree of heterogeneity observed in patients with CRPC and further highlight SLFN5 as a clinically relevant target for CRPC. SIGNIFICANCE: This study identifies SLFN5 as a novel regulator of the LAT1 amino acid transporter and an essential contributor to mTORC1 activity in castration-resistant prostate cancer.
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http://dx.doi.org/10.1158/0008-5472.CAN-20-3694DOI Listing
July 2021

Functional mapping of androgen receptor enhancer activity.

Genome Biol 2021 05 11;22(1):149. Epub 2021 May 11.

Vancouver Prostate Centre, Department of Urologic Science, University of British Columbia, Vancouver, Canada.

Background: Androgen receptor (AR) is critical to the initiation, growth, and progression of prostate cancer. Once activated, the AR binds to cis-regulatory enhancer elements on DNA that drive gene expression. Yet, there are 10-100× more binding sites than differentially expressed genes. It is unclear how or if these excess binding sites impact gene transcription.

Results: To characterize the regulatory logic of AR-mediated transcription, we generated a locus-specific map of enhancer activity by functionally testing all common clinical AR binding sites with Self-Transcribing Active Regulatory Regions sequencing (STARRseq). Only 7% of AR binding sites displayed androgen-dependent enhancer activity. Instead, the vast majority of AR binding sites were either inactive or constitutively active enhancers. These annotations strongly correlated with enhancer-associated features of both in vitro cell lines and clinical prostate cancer samples. Evaluating the effect of each enhancer class on transcription, we found that AR-regulated enhancers frequently interact with promoters and form central chromosomal loops that are required for transcription. Somatic mutations of these critical AR-regulated enhancers often impact enhancer activity.

Conclusions: Using a functional map of AR enhancer activity, we demonstrated that AR-regulated enhancers act as a regulatory hub that increases interactions with other AR binding sites and gene promoters.
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http://dx.doi.org/10.1186/s13059-021-02339-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8112059PMC
May 2021

Development of Novel Inhibitors Targeting the D-Box of the DNA Binding Domain of Androgen Receptor.

Int J Mol Sci 2021 Mar 2;22(5). Epub 2021 Mar 2.

Vancouver Prostate Centre, University of British Columbia, 2660 Oak Street, Vancouver, BC V6H 3Z6, Canada.

The inhibition of the androgen receptor (AR) is an established strategy in prostate cancer (PCa) treatment until drug resistance develops either through mutations in the ligand-binding domain (LBD) portion of the receptor or its deletion. We previously identified a druggable pocket on the DNA binding domain (DBD) dimerization surface of the AR and reported several potent inhibitors that effectively disrupted DBD-DBD interactions and consequently demonstrated certain antineoplastic activity. Here we describe further development of small molecule inhibitors of AR DBD dimerization and provide their broad biological characterization. The developed compounds demonstrate improved activity in the mammalian two-hybrid assay, enhanced inhibition of AR-V7 transcriptional activity, and improved microsomal stability. These findings position us for the development of AR inhibitors with entirely novel mechanisms of action that would bypass most forms of PCa treatment resistance, including the truncation of the LBD of the AR.
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http://dx.doi.org/10.3390/ijms22052493DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7958344PMC
March 2021

A noncanonical AR addiction drives enzalutamide resistance in prostate cancer.

Nat Commun 2021 03 9;12(1):1521. Epub 2021 Mar 9.

Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, MN, USA.

Resistance to next-generation anti-androgen enzalutamide (ENZ) constitutes a major challenge for the treatment of castration-resistant prostate cancer (CRPC). By performing genome-wide ChIP-seq profiling in ENZ-resistant CRPC cells we identify a set of androgen receptor (AR) binding sites with increased AR binding intensity (ARBS-gained). While ARBS-gained loci lack the canonical androgen response elements (ARE) and pioneer factor FOXA1 binding motifs, they are highly enriched with CpG islands and the binding sites of unmethylated CpG dinucleotide-binding protein CXXC5 and the partner TET2. RNA-seq analysis reveals that both CXXC5 and its regulated genes including ID1 are upregulated in ENZ-resistant cell lines and these results are further confirmed in patient-derived xenografts (PDXs) and patient specimens. Consistent with the finding that ARBS-gained loci are highly enriched with H3K27ac modification, ENZ-resistant PCa cells, organoids, xenografts and PDXs are hyper-sensitive to NEO2734, a dual inhibitor of BET and CBP/p300 proteins. These results not only reveal a noncanonical AR function in acquisition of ENZ resistance, but also posit a treatment strategy to target this vulnerability in ENZ-resistant CRPC.
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http://dx.doi.org/10.1038/s41467-021-21860-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7943793PMC
March 2021

Discovery of New Catalytic Topoisomerase II Inhibitors for Anticancer Therapeutics.

Front Oncol 2020 1;10:633142. Epub 2021 Feb 1.

The Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada.

Poison inhibitors of DNA topoisomerase II (TOP2) are clinically used drugs that cause cancer cell death by inducing DNA damage, which mechanism of action is also associated with serious side effects such as secondary malignancy and cardiotoxicity. In contrast, TOP2 catalytic inhibitors induce limited DNA damage, have low cytotoxicity, and are effective in suppressing cancer cell proliferation. They have been sought after to be prospective anticancer therapies. Herein the discovery of new TOP2 catalytic inhibitors is described. A new druggable pocket of TOP2 protein at its DNA binding domain was used as a docking site to virtually screen ~6 million molecules from the ZINC15 library. The lead compound, T60, was characterized to be a catalytic TOP2 inhibitor that binds TOP2 protein and disrupts TOP2 from interacting with DNA, resulting in no DNA cleavage. It has low cytotoxicity, but strongly inhibits cancer cell proliferation and xenograft growth. T60 also inhibits androgen receptor activity and prostate cancer cell growth. These results indicate that T60 is a promising candidate compound that can be further developed into new anticancer drugs.
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http://dx.doi.org/10.3389/fonc.2020.633142DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7883873PMC
February 2021

Steroidogenesis in Peripheral and Transition Zones of Human Prostate Cancer Tissue.

Int J Mol Sci 2021 Jan 6;22(2). Epub 2021 Jan 6.

The Vancouver Prostate Centre, Vancouver General Hospital, 2660 Oak Street, Vancouver, BC V6H 3Z6, Canada.

The peripheral zone (PZ) and transition zone (TZ) represent about 70% of the human prostate gland with each zone having differential ability to develop prostate cancer. Androgens and their receptor are the primary driving cause of prostate cancer growth and eventually castration-resistant prostate cancer (CRPC). De novo steroidogenesis has been identified as a key mechanism that develops during CRPC. Currently, there is very limited information available on human prostate tissue steroidogenesis. The purpose of the present study was to investigate steroid metabolism in human prostate cancer tissues with comparison between PZ and TZ. Human prostate cancer tumors were procured from the patients who underwent radical prostatectomy without any neoadjuvant therapy. Human prostate homogenates were used to quantify steroid levels intrinsically present in the tissues as well as formed after incubation with 2 µg/mL of 17-hydroxypregnenolone (17-OH-pregnenolone) or progesterone. A Waters Acquity ultraperformance liquid chromatography coupled to a Quattro Premier XE tandem quadrupole mass spectrometer using a C column was used to measure thirteen steroids from the classical and backdoor steroidogenesis pathways. The intrinsic prostate tissue steroid levels were similar between PZ and TZ with dehydroepiandrosterone (DHEA), dihydrotestosterone (DHT), pregnenolone and 17-OH-pregnenolone levels higher than the other steroids measured. Interestingly, 5-pregnan-3,20-dione, 5-pregnan-3-ol-20-one, and 5-pregnan-17-ol-3,20-dione formation was significantly higher in both the zones of prostate tissues, whereas, androstenedione, testosterone, DHT, and progesterone levels were significantly lower after 60 min incubation compared to the 0 min control incubations. The incubations with progesterone had a similar outcome with 5-pregnan-3,20-dione and 5-pregnan-3-ol-20-one levels were elevated and the levels of DHT were lower in both PZ and TZ tissues. The net changes in steroid formation after the incubation were more observable with 17-OH-pregnenolone than with progesterone. In our knowledge, this is the first report of comprehensive analyses of intrinsic prostate tissue steroids and precursor-driven steroid metabolism using a sensitive liquid chromatography-mass spectrometry assay. In summary, the PZ and TZ of human prostate exhibited similar steroidogenic ability with distinction in the manner each zone utilizes the steroid precursors to divert the activity towards backdoor pathway through a complex matrix of steroidogenic mechanisms.
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http://dx.doi.org/10.3390/ijms22020487DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7825320PMC
January 2021

Clusterin Deficiency Predisposes C57BL/6j Mice to Cationic Bovine Serum Albumin-Induced Glomerular Inflammation.

J Inflamm Res 2020 24;13:969-983. Epub 2020 Nov 24.

Department of Urologic Sciences, University of British Columbia, Vancouver, BC V6H 3Z6, Canada.

Background: Membranous nephropathy (MN) is a specific entity of glomerulonephritis, and its glomerular inflammation is characterized by the deposition of immune complexes in the glomerular basement membrane and proteinuria. However, the molecular mechanisms underlying the glomerular inflammation of MN are not fully understood. This study was designed to investigate the role of clusterin (CLU) in the development of MN using a mouse model of cationic bovine serum albumin (cBSA)-induced MN.

Methods: Both wild-type C57BL/6j (WT) and CLU-knockout C57BL/6j (CLU-KO) mice were immunized with cBSA. The kidney function was determined by the levels of serum creatinine (SCr), blood urea nitrogen (BUN) and urinary protein. MN and glomerular deposits of CLU, complement C3 and immunoglobulins (Igs) were determined by histological analyses. Serum proteins were analyzed by the enzyme-linked immunosorbent assay, Western blot and liquid chromatography-mass spectrometry.

Results: Here, we showed that after cBSA immunization, SCr and proteinuria were increased in CLU-KO mice but not in WT mice. Similarly, severe glomerular atrophy and mesangial expansion along with C3 deposit were only found in the kidneys of CLU-KO mice but not in WT mice. However, there were no differences of serum IgG and complement 3 levels between CLU-KO and WT mice. In the serum of WT mice, CLU bound to anti-cBSA IgG, complements (eg, C8), proteinase/protease inhibitors and antioxidative proteins to form a complex, and incubation with WT serum reduced the complement-dependent lysis of podocytes in cultures.

Conclusion: Our data suggest that a CLU deficiency induces cBSA-initiated glomerular inflammation of MN in a disease-resistant strain of mice, suggesting an anti-glomerular inflammatory function of CLU in the resistance to MN development. This function may be at least in part due to the formation of CLU-anti-cBSA Igs complex that prevents glomerular inflammation or injury in the disease-resistant mice.
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http://dx.doi.org/10.2147/JIR.S285985DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7699998PMC
November 2020

A polymeric paste-drug formulation for local treatment of upper tract urothelial carcinoma.

Urol Oncol 2021 03 26;39(3):194.e1-194.e7. Epub 2020 Nov 26.

Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada. Electronic address:

Background: Intravesical instillation of chemo- or immunotherapy is commonly used in bladder cancer. Upper tract urothelial carcinoma (UTUC) shares similar pathological features, but current formulations are not suitable for direct instillation to the upper urinary tract.

Objective: To evaluate in vivo applicability, characteristics and toxicity of ST-UC, a mucoadhesive polymeric paste formulation of gemcitabine, for upper urinary tract instillation.

Material And Methods: Three pigs received 10 ml of ST-UC (100 mg/ml gemcitabine) retrogradely into 1 renal pelvis for pharmacokinetic studies. Four days later, a second injection into the contralateral renal pelvis was followed by serial euthanasia of the pigs and nephroureterectomy after 1, 3, and 6 hours. Adverse effects were monitored. Urine, serum, and tissue gemcitabine concentrations were measured, along with histologic examination of the upper urinary tract.

Results: Retrograde instillation of ST-UC was well tolerated with mild, completely receding hydronephrosis. Urine gemcitabine concentrations were highest in the first 3-hour collection interval. Hundred percent of gemcitabine was recovered in the urine within 24 hours. Serum peak concentrations (c) of gemcitabine were low at 5.5 µg/ml compared to the 10 to 30 µg/ml levels observed after a single intravenous dose of 1,000 mg/m gemcitabine. The formulation was still traceable after one hour and gemcitabine tissue concentrations are supportive of this extended drug exposure. No major histopathological changes were observed. The main limitation of this study is the lack of antitumor activity data.

Conclusion: This preclinical evaluation of ST-UC demonstrated feasible instillation in the renal pelvis, no significant safety concerns, and sustained release of gemcitabine.
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http://dx.doi.org/10.1016/j.urolonc.2020.07.028DOI Listing
March 2021

Clusterin regulates macrophage expansion, polarization and phagocytic activity in response to inflammation in the kidneys.

Immunol Cell Biol 2021 03 16;99(3):274-287. Epub 2020 Oct 16.

Department of Urologic Sciences, The University of British Columbia, Vancouver, BC, V5Z 1M9, Canada.

Clusterin (CLU) is a multifunctional protein localized extracellularly and intracellularly. Although CLU-knockout (KO) mice are more susceptible to renal ischemia-reperfusion injury (IRI), the mechanisms underlying the actions of CLU in IRI are not fully understood. Macrophages are key regulators of IRI severity and tissue repair. Therefore, we investigated the role of CLU in macrophage polarization and phagocytosis. Renal IRI was induced in wild-type (WT) or CLU-KO C57BL/6 mice by clamping the renal pedicles for 30 min at 32°C. Peritoneal macrophages were activated via an intraperitoneal injection of lipopolysaccharide (LPS). Renal tissue damage was examined using histology, whereas leukocyte phenotypes were assessed using flow cytometry and immunohistochemistry. We found that monocytes/macrophages expressed the CLU protein that was upregulated by hypoxia. The percentages of macrophages (F4/80 , CD11b or MAC3 ) infiltrating the kidneys of WT mice were significantly less than those in CLU-KO mice after IRI. The M1/M2 phenotype ratio of the macrophages in WT kidneys decreased at day 7 post-IRI when the injury was repaired, whereas that in KO kidneys increased consistently as tissue injury persisted. In response to LPS stimulation, WT mice produced fewer M1 macrophages, but not M2, than the control did. Phagocytosis was stimulated by CLU expression in macrophages compared with the CLU null controls and by the exogenous CLU protein. In conclusion, CLU suppresses macrophage infiltration and proinflammatory M1 polarization during the recovery period following IRI, and enhances phagocytic activity, which may be partly responsible for tissue repair in the kidneys of WT mice after injury.
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http://dx.doi.org/10.1111/imcb.12405DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7984284PMC
March 2021

Tailoring Intensity of Active Surveillance for Low-Risk Prostate Cancer Based on Individualized Prediction of Risk Stability.

JAMA Oncol 2020 10 8;6(10):e203187. Epub 2020 Oct 8.

Fred Hutchinson Cancer Research Center, Cancer Prevention Program, Public Health Sciences, Seattle, Washington.

Importance: Active surveillance is increasingly recognized as the preferred standard of care for men with low-risk prostate cancer. However, active surveillance requires repeated assessments, including prostate-specific antigen tests and biopsies that may increase anxiety, risk of complications, and cost.

Objective: To identify and validate clinical parameters that can identify men who can safely defer follow-up prostate cancer assessments.

Design, Setting, And Participants: The Canary Prostate Active Surveillance Study (PASS) is a multicenter, prospective active surveillance cohort study initiated in July 2008, with ongoing accrual and a median follow-up period of 4.1 years. Men with prostate cancer managed with active surveillance from 9 North American academic medical centers were enrolled. Blood tests and biopsies were conducted on a defined schedule for least 5 years after enrollment. Model validation was performed among men at the University of California, San Francisco (UCSF) who did not enroll in PASS. Men with Gleason grade group 1 prostate cancer diagnosed since 2003 and enrolled in PASS before 2017 with at least 1 confirmatory biopsy after diagnosis were included. A total of 850 men met these criteria and had adequate follow-up. For the UCSF validation study, 533 active surveillance patients meeting the same criteria were identified. Exclusion criteria were treatment within 6 months of diagnosis, diagnosis before 2003, Gleason grade score of at least 2 at diagnosis or first surveillance biopsy, no surveillance biopsy, or missing data.

Exposures: Active surveillance for prostate cancer.

Main Outcomes And Measures: Time from confirmatory biopsy to reclassification, defined as Gleason grade group 2 or higher on subsequent biopsy.

Results: A total of 850 men (median [interquartile range] age, 64 [58-68] years; 774 [91%] White) were included in the PASS cohort. A total of 533 men (median [interquartile range] age, 61 [57-65] years; 422 [79%] White) were included in the UCSF cohort. Parameters predictive of reclassification on multivariable analysis included maximum percent positive cores (hazard ratio [HR], 1.30 [95% CI, 1.09-1.56]; P = .004), history of any negative biopsy after diagnosis (1 vs 0: HR, 0.52 [95% CI, 0.38-0.71]; P < .001 and ≥2 vs 0: HR, 0.18 [95% CI, 0.08-0.4]; P < .001), time since diagnosis (HR, 1.62 [95% CI, 1.28-2.05]; P < .001), body mass index (HR, 1.08 [95% CI, 1.05-1.12]; P < .001), prostate size (HR, 0.40 [95% CI, 0.25-0.62]; P < .001), prostate-specific antigen at diagnosis (HR, 1.51 [95% CI, 1.15-1.98]; P = .003), and prostate-specific antigen kinetics (HR, 1.46 [95% CI, 1.23-1.73]; P < .001). For prediction of nonreclassification at 4 years, the area under the receiver operating curve was 0.70 for the PASS cohort and 0.70 for the UCSF validation cohort. This model achieved a negative predictive value of 0.88 (95% CI, 0.83-0.94) for those in the bottom 25th percentile of risk and of 0.95 (95% CI, 0.89-1.00) for those in the bottom 10th percentile.

Conclusions And Relevance: In this study, among men with low-risk prostate cancer, heterogeneity prevailed in risk of subsequent disease reclassification. These findings suggest that active surveillance intensity can be modulated based on an individual's risk parameters and that many men may be safely monitored with a substantially less intensive surveillance regimen.
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http://dx.doi.org/10.1001/jamaoncol.2020.3187DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7453344PMC
October 2020

Paternally Expressed Gene 10 (PEG10) Promotes Growth, Invasion, and Survival of Bladder Cancer.

Mol Cancer Ther 2020 10 26;19(10):2210-2220. Epub 2020 Aug 26.

The Vancouver Prostate Centre and Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia, Canada.

() has been associated with neuroendocrine muscle-invasive bladder cancer (MIBC), a subtype of the disease with the poorest survival. In this work, we further characterized the expression pattern of in The Cancer Genome Atlas database of 412 patients with MIBC, and found that, compared with other subtypes, mRNA level was enhanced in neuroendocrine-like MIBC and highly correlated with other neuroendocrine markers. PEG10 protein level also associated with neuroendocrine markers in a tissue microarray of 82 cases. In bladder cancer cell lines, PEG10 expression was induced in drug-resistant compared with parental cells, and knocking down of PEG10 resensitized cells to chemotherapy. Loss of PEG10 increased protein levels of cell-cycle regulators p21 and p27 and delayed G-S-phase transition, while overexpression of PEG10 enhanced cancer cell proliferation. PEG10 silencing also lowered levels of SLUG and SNAIL, leading to reduced invasion and migration. In an orthotopic bladder cancer model, systemic treatment with PEG10 antisense oligonucleotide delayed progression of T24 xenografts. In summary, elevated expression of in MIBC may contribute to the disease progression by promoting survival, proliferation, and metastasis. Targeting PEG10 is a novel potential therapeutic approach for a subset of bladder cancers.
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http://dx.doi.org/10.1158/1535-7163.MCT-19-1031DOI Listing
October 2020

Small Renal Mass Surveillance: Histology-specific Growth Rates in a Biopsy-characterized Cohort.

Eur Urol 2020 09 14;78(3):460-467. Epub 2020 Jul 14.

Division of Urology, Department of Surgery, Princess Margaret Cancer Centre and the University Health Network, University of Toronto, Toronto, ON, Canada.

Background: Most reports of active surveillance (AS) of small renal masses (SRMs) lack biopsy confirmation, and therefore include benign tumors and different subtypes of renal cell carcinoma (RCC).

Objective: We compared the growth rates and progression of different histologic subtypes of RCC SRMs (SRM) in the largest cohort of patients with biopsy-characterized SRMs on AS.

Design, Setting, And Participants: Data from patients in a multicenter Canadian trial and a Princess Margaret cohort were combined to include 136 biopsy-proven SRM lesions managed by AS, with treatment deferred until progression or patient/surgeon decision.

Outcome Measurements And Statistical Analysis: Growth curves were estimated from serial tumor size measures. Tumor progression was defined by sustained size ≥4 cm or volume doubling within 1 yr.

Results And Limitations: Median follow-up for patients who remained on AS was 5.8 yr (interquartile range 3.4-7.5 yr). Clear cell RCC SRMs (SRM) grew faster than papillary type 1 SRMs (0.25 and 0.02 cm/yr on average, respectively, p =  0.0003). Overall, 60 SRM lesions progressed: 49 (82%) by rapid growth (volume doubling), seven (12%) increasing to ≥4 cm, and four (6.7%) by both criteria. Six patients developed metastases, and all were of clear cell RCC histology. Limitations include the use of different imaging modalities and a lack of central imaging review.

Conclusions: Tumor growth varies between histologic subtypes of SRM and among SRM, which likely reflects individual host and tumor biology. Without validated biomarkers that predict this variation, initial follow-up of histologically characterized SRMs can inform personalized treatment for patients on AS.

Patient Summary: Many small kidney cancers are suitable for surveillance and can be monitored over time for change. We demonstrate that different types of kidney cancers grow at different rates and are at different risks of progression. These results may guide better personalized treatment.
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http://dx.doi.org/10.1016/j.eururo.2020.06.053DOI Listing
September 2020

LIN28B promotes the development of neuroendocrine prostate cancer.

J Clin Invest 2020 10;130(10):5338-5348

Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia, Canada.

Therapy-induced neuroendocrine prostate cancer (t-NEPC) is a highly aggressive subtype of prostate cancer with poor patient survival. Emerging evidence indicates that t-NEPC can develop when prostate adenocarcinoma cells acquire cancer stem-like cell signaling in the presence of androgen receptor inhibition, followed by redifferentiation toward neuroendocrine lineage and subsequent t-NEPC progression. Whether the stem-like signaling is controlled by the core pluripotency stem cell genes (e.g., LIN28 and SOX2) remains unknown. Here, we report that the transcription of the LIN28B isoform and SOX2 were co-upregulated in t-NEPC patient tumors, patient-derived xenografts, transgenic mice, and cell models. Immunohistochemistry validated that LIN28B and SOX2 protein expression were elevated in t-NEPC patient biopsies. Using prostate adenocarcinoma and t-NEPC cell models, we demonstrated that LIN28B induced a stem-like gene network, neuroendocrine biomarkers, and neuroendocrine cell morphology. LIN28B depletion by CRISPR inhibited t-NEPC tumorigenesis and xenograft growth. These LIN28B functions were mediated mainly through the suppression of let-7 miRNA expression, resulting in de-repression of the transcription factor HMGA2 and HMGA2-mediated SOX2 expression. This study revealed a mechanism by which t-NEPC can develop through the LIN28B/let-7/SOX2 axis that regulates a cancer cell stem-like gene network, highlighting LIN28B as a potential therapeutic target in t-NEPC.
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http://dx.doi.org/10.1172/JCI135373DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7524485PMC
October 2020

Deep Docking: A Deep Learning Platform for Augmentation of Structure Based Drug Discovery.

ACS Cent Sci 2020 Jun 19;6(6):939-949. Epub 2020 May 19.

Vancouver Prostate Centre, University of British Columbia, Vancouver, British Columbia V6H3Z6, Canada.

Drug discovery is a rigorous process that requires billion dollars of investments and decades of research to bring a molecule "from bench to a bedside". While virtual docking can significantly accelerate the process of drug discovery, it ultimately lags the current rate of expansion of chemical databases that already exceed billions of molecular records. This recent surge of small molecules availability presents great drug discovery opportunities, but also demands much faster screening protocols. In order to address this challenge, we herein introduce Deep Docking (), a novel deep learning platform that is suitable for docking billions of molecular structures in a rapid, yet accurate fashion. The approach utilizes quantitative structure-activity relationship (QSAR) deep models trained on docking scores of subsets of a chemical library to approximate the docking outcome for yet unprocessed entries and, therefore, to remove unfavorable molecules in an iterative manner. The use of methodology in conjunction with the FRED docking program allowed rapid and accurate calculation of docking scores for 1.36 billion molecules from the ZINC15 library against 12 prominent target proteins and demonstrated up to 100-fold data reduction and 6000-fold enrichment of high scoring molecules (without notable loss of favorably docked entities). The protocol can readily be used in conjunction with any docking program and was made publicly available.
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http://dx.doi.org/10.1021/acscentsci.0c00229DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7318080PMC
June 2020

p300-Mediated Acetylation of Histone Demethylase JMJD1A Prevents Its Degradation by Ubiquitin Ligase STUB1 and Enhances Its Activity in Prostate Cancer.

Cancer Res 2020 08 10;80(15):3074-3087. Epub 2020 Jun 10.

Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland.

The androgen receptor (AR) pathway plays a central role in the development of castration-resistant prostate cancer (CRPC). The histone demethylase JMJD1A has been shown to regulate activities of AR and c-Myc transcription factors and promote prostate cancer progression. Here, we report that JMJD1A protein stability is controlled by the ubiquitin ligase STUB1. High levels of JMJD1A were strongly correlated with low STUB1 levels in human CRPC specimens. STUB1 inhibited AR activity, AR-V7 levels, and prostate cancer cell growth partly through degradation of JMJD1A. Furthermore, the acetyltransferase p300 acetylated JMJD1A at lysine (K) 421, a modification that recruits the BET family member BRD4 to block JMJD1A degradation and promote JMJD1A recruitment to AR targets. Increased levels of both total and K421-acetylated JMJD1A were observed in prostate cancer cells as they developed resistance to the AR antagonist enzalutamide. Treatment of prostate cancer cells with either p300 or BET inhibitors destabilized JMJD1A, and enzalutamide-resistant prostate cancer cells were more sensitive than parental cells to these inhibitors. Together, our findings identify a critical role for acetylation of JMJD1A in regulating JMJD1A stability and AR activity in CRPC. These newly identified mechanisms controlling JMJD1A protein stability provide potential druggable targets to encourage the development of additional therapies for advanced prostate cancer. SIGNIFICANCE: Identification of mechanisms regulating JMJD1A protein stability reveals new strategies to destabilize JMJD1A and concomitantly inhibit AR activities as potential prostate cancer therapy.
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http://dx.doi.org/10.1158/0008-5472.CAN-20-0233DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7415556PMC
August 2020

Activating AKT1 and PIK3CA Mutations in Metastatic Castration-Resistant Prostate Cancer.

Eur Urol 2020 12 22;78(6):834-844. Epub 2020 May 22.

Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada. Electronic address:

Background: Activating mutations in AKT1 and PIK3CA are undercharacterised in metastatic castration-resistant prostate cancer (mCRPC), but are linked to activation of phosphatidylinositol 3-kinase (PI3K) signalling and sensitivity to pathway inhibitors in other cancers.

Objective: To determine the prevalence, genomic context, and clinical associations of AKT1/PIK3CA activating mutations in mCRPC.

Design, Setting, And Participants: We analysed targeted cell-free DNA (cfDNA) sequencing data from 599 metastatic prostate cancer patients with circulating tumour DNA (ctDNA) content above 2%.

Outcome Measurements And Statistical Analysis: In patients with AKT1/PIK3CA mutations, cfDNA was subjected to PTEN intron sequencing and matched diagnostic tumour tissue was analysed when possible.

Results And Limitations: Of the patients, 6.0% (36/599) harboured somatic clonal activating mutation(s) in AKT1 or PIK3CA. Mutant allele-specific imbalance was common. Clonal mutations in mCRPC ctDNA were typically detected in pretreatment primary tissue and were consistent across serial ctDNA collections. AKT1/PIK3CA-mutant mCRPC had fewer androgen receptor (AR) gene copies than AKT1/PIK3CA wild-type mCRPC (median 4.7 vs 10.3, p =  0.003). AKT1 mutations were mutually exclusive with PTEN alterations. Patients with and without AKT1/PIK3CA mutations showed similar clinical outcomes with standard of care treatments. A heavily pretreated mCRPC patient with an AKT1 mutation experienced a 50% decline in prostate-specific antigen with Akt inhibitor (ipatasertib) monotherapy. Ipatasertib also had a marked antitumour effect in a patient-derived xenograft harbouring an AKT1 mutation. Limitations include the inability to assess AKT1/PIK3CA correlatives in ctDNA-negative patients.

Conclusions: AKT1/PIK3CA activating mutations are relatively common and delineate a distinct mCRPC molecular subtype with low-level AR copy gain. Clonal prevalence and evidence of mutant allele selection propose PI3K pathway dependency in selected patients. The use of cfDNA screening enables prospective clinical trials to test PI3K pathway inhibitors in this population.

Patient Summary: Of advanced prostate cancer cases, 6% have activating mutations in the genes AKT1 or PIK3CA. These mutations can be identified using a blood test and may help select patients suitable for clinical trials of phosphatidylinositol 3-kinase inhibitors.
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http://dx.doi.org/10.1016/j.eururo.2020.04.058DOI Listing
December 2020

Magnetic Resonance Imaging for the Detection of High Grade Cancer in the Canary Prostate Active Surveillance Study.

J Urol 2020 10 28;204(4):701-706. Epub 2020 Apr 28.

Fred Hutchinson Cancer Research Center, University of Washington, Seattle, Washington.

Purpose: We investigated the ability of prostate magnetic resonance imaging to detect Gleason Grade Group 2 or greater cancer in a standardized, multi-institutional active surveillance cohort.

Materials And Methods: We evaluated men enrolled in Canary Prostate Active Surveillance Study with Gleason Grade Group less than 2 and who underwent biopsy within 12 months of multiparametric magnetic resonance imaging. Our primary outcome was biopsy reclassification to Gleason Grade Group 2 or greater. We evaluated the performance of magnetic resonance imaging PI-RADS® score and clinical factors. Multivariable logistic regression models were fit with magnetic resonance imaging and clinical factors and used to perform receiver operating curve analyses.

Results: There were 361 participants with 395 prostate magnetic resonance imaging studies with a median followup of 4.1 (IQR 2.0-7.6) years. Overall 108 (27%) biopsies showed reclassification. Defining positive magnetic resonance imaging as PI-RADS 3-5, the negative predictive value and positive predictive value for detecting Gleason Grade Group 2 or greater cancer was 83% (95% CI 76-90) and 31% (95% CI 26-37), respectively. PI-RADS was significantly associated with reclassification (PI-RADS 5 vs 1 and 2 OR 2.71, 95% CI 1.21-6.17, p=0.016) in a multivariable model but did not improve upon a model with only clinical factors (AUC 0.768 vs 0.762). In 194 fusion biopsies higher grade cancer was found in targeted cores in 21 (11%) instances, while 25 (13%) had higher grade cancer in the systematic cores.

Conclusions: This study adds the largest cohort data to the body of literature for magnetic resonance imaging in active surveillance, recommending systematic biopsy in patients with negative magnetic resonance imaging and the inclusion of systematic biopsy in patients with positive magnetic resonance imaging.
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http://dx.doi.org/10.1097/JU.0000000000001088DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7483329PMC
October 2020

17-Gene Genomic Prostate Score Test Results in the Canary Prostate Active Surveillance Study (PASS) Cohort.

J Clin Oncol 2020 05 4;38(14):1549-1557. Epub 2020 Mar 4.

Cancer Prevention Program, Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA.

Purpose: The 17-gene Onco DX Genomic Prostate Score (GPS) test predicts adverse pathology (AP) in patients with low-risk prostate cancer treated with immediate surgery. We evaluated the GPS test as a predictor of outcomes in a multicenter active surveillance cohort.

Materials And Methods: Diagnostic biopsy tissue was obtained from men enrolled at 8 sites in the Canary Prostate Active Surveillance Study. The primary endpoint was AP (Gleason Grade Group [GG] ≥ 3, ≥ pT3a) in men who underwent radical prostatectomy (RP) after initial surveillance. Multivariable regression models for interval-censored data were used to evaluate the association between AP and GPS. Inverse probability of censoring weighting was applied to adjust for informative censoring. Predictiveness curves were used to evaluate how models stratified risk of AP. Association between GPS and time to upgrade on surveillance biopsy was evaluated using Cox proportional hazards models.

Results: GPS results were obtained for 432 men (median follow-up, 4.6 years); 101 underwent RP after a median 2.1 years of surveillance, and 52 had AP. A total of 167 men (39%) upgraded at a subsequent biopsy. GPS was significantly associated with AP when adjusted for diagnostic GG (hazards ratio [HR]/5 GPS units, 1.18; 95% CI, 1.04 to 1.44; = .030), but not when also adjusted for prostate-specific antigen density (PSAD; HR, 1.85; 95% CI, 0.99 to 4.19; = .066). Models containing PSAD and GG, or PSAD, GG, and GPS may stratify risk better than a model with GPS and GG. No association was observed between GPS and subsequent biopsy upgrade ( = .48).

Conclusion: In our study, the independent association of GPS with AP after initial active surveillance was not statistically significant, and there was no association with upgrading in surveillance biopsy. Adding GPS to a model containing PSAD and diagnostic GG did not significantly improve stratification of risk for AP over the clinical variables alone.
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http://dx.doi.org/10.1200/JCO.19.02267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7213589PMC
May 2020

Plasma Circulating Tumor DNA and Clonal Hematopoiesis in Metastatic Renal Cell Carcinoma.

Clin Genitourin Cancer 2020 08 8;18(4):322-331.e2. Epub 2020 Jan 8.

Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, British Columbia, Canada; Department of Medical Oncology, BC Cancer, British Columbia, Canada.

Background: There is a lack of molecularly-informed biomarkers for patients with metastatic renal cell carcinoma (RCC). Plasma cell-free DNA (cfDNA) sequencing is a minimally-invasive alternative to tissue for profiling the genome in other cancers but relevance in metastatic RCC remains unclear.

Materials And Methods: Whole blood was collected from 55 patients with metastatic RCC. Plasma cfDNA and leukocyte DNA were subjected to targeted sequencing across 981 cancer genes. Matched tumor tissue from 14 patients was analyzed.

Results: Thirty-three percent of patients had evidence for RCC-derived circulating tumor DNA (ctDNA), significantly lower than patients with metastatic prostate or bladder cancer analyzed using the same approach. Among ctDNA-positive patients, ctDNA fraction averaged only 3.9% and showed no strong association with clinical variables. In these patients, the most commonly mutated genes were VHL, BAP1, and PBRM1, and matched tissue concordance was 77%. Evidence of somatic expansions unrelated to RCC, such as clonal hematopoiesis of indeterminate potential, were detected in 43% of patients. Pathogenic germline mutations in DNA repair genes were detected in 11% of patients. CtDNA-positive patients had shorter overall survival and progression-free survival on first-line therapy. Patients with evidence of clonal hematopoiesis of indeterminate potential had an intermediate prognosis compared with ctDNA-positive and -negative patients.

Conclusions: CfDNA sequencing enables straightforward characterization of the somatic RCC genome in a minority of patients with metastatic RCC. Owing to low ctDNA abundance, and the presence of non-RCC derived somatic clones in circulation, cfDNA sequencing may not be a simple pan-patient alternative to tissue biopsy in metastatic RCC.
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http://dx.doi.org/10.1016/j.clgc.2019.12.018DOI Listing
August 2020

Cancer Cells Employ Nuclear Caspase-8 to Overcome the p53-Dependent G2/M Checkpoint through Cleavage of USP28.

Mol Cell 2020 03 22;77(5):970-984.e7. Epub 2020 Jan 22.

Experimental Dermatology, Department of Dermatology, TU-Dresden, Dresden 01307, Germany; Center for Regenerative Therapies Dresden, TU-Dresden, Dresden 01307, Germany. Electronic address:

Cytosolic caspase-8 is a mediator of death receptor signaling. While caspase-8 expression is lost in some tumors, it is increased in others, indicating a conditional pro-survival function of caspase-8 in cancer. Here, we show that tumor cells employ DNA-damage-induced nuclear caspase-8 to override the p53-dependent G2/M cell-cycle checkpoint. Caspase-8 is upregulated and localized to the nucleus in multiple human cancers, correlating with treatment resistance and poor clinical outcome. Depletion of caspase-8 causes G2/M arrest, stabilization of p53, and induction of p53-dependent intrinsic apoptosis in tumor cells. In the nucleus, caspase-8 cleaves and inactivates the ubiquitin-specific peptidase 28 (USP28), preventing USP28 from de-ubiquitinating and stabilizing wild-type p53. This results in de facto p53 protein loss, switching cell fate from apoptosis toward mitosis. In summary, our work identifies a non-canonical role of caspase-8 exploited by cancer cells to override the p53-dependent G2/M cell-cycle checkpoint.
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http://dx.doi.org/10.1016/j.molcel.2019.12.023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7060810PMC
March 2020

Design and Characterization of Injectable Poly(Lactic-Co-Glycolic Acid) Pastes for Sustained and Local Drug Release.

Pharm Res 2020 Jan 21;37(3):36. Epub 2020 Jan 21.

Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada.

Purpose: We describe the preparation of injectable polymeric paste (IPP) formulations for local and sustained release of drugs. Furthermore, we include the characterization and possible applications of such pastes. Particular attention is paid to characteristics relevant to the successful clinical formulation development, such as viscosity, injectability, degradation, drug release, sterilization, stability performance and pharmacokinetics.

Methods: Paste injectability was characterized using measured viscosity and the Hagen-Poiseuille equation to determine injection forces. Drug degradation, release and formulation stability experiments were performed in vitro and drug levels were quantified using HPLC-UV methods. Pharmacokinetic evaluation of sustained-release lidocaine IPPs used five groups of six rats receiving increasing doses subcutaneously. An anti-cancer formulation was evaluated in a subcutaneous tumor xenograft mouse model.

Results: The viscosity and injectability of IPPs could be controlled by changing the polymeric composition. IPPs demonstrated good long-term stability and tunable drug-release with low systemic exposure in vivo in rats. Preliminary data in a subcutaneous tumor model points to a sustained anticancer effect.

Conclusions: These IPPs are tunable platforms for local and sustained delivery of drugs and have potential for further clinical development to treat a number of diseases.
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http://dx.doi.org/10.1007/s11095-019-2730-4DOI Listing
January 2020

Transient Sox9 Expression Facilitates Resistance to Androgen-Targeted Therapy in Prostate Cancer.

Clin Cancer Res 2020 04 9;26(7):1678-1689. Epub 2020 Jan 9.

Vancouver Prostate Centre, Vancouver, British Columbia, Canada.

Purpose: Patients with metastatic prostate cancer are increasingly presenting with treatment-resistant, androgen receptor-negative/low (AR) tumors, with or without neuroendocrine characteristics, in processes attributed to tumor cell plasticity. This plasticity has been modeled by Rb1/p53 knockdown/knockout and is accompanied by overexpression of the pluripotency factor, Sox2. Here, we explore the role of the developmental transcription factor Sox9 in the process of prostate cancer therapy response and tumor progression.

Experimental Design: Unique prostate cancer cell models that capture AR stem cell-like intermediates were analyzed for features of plasticity and the functional role of Sox9. Human prostate cancer xenografts and tissue microarrays were evaluated for temporal alterations in Sox9 expression. The role of NF-κB pathway activity in Sox9 overexpression was explored.

Results: Prostate cancer stem cell-like intermediates have reduced Rb1 and p53 protein expression and overexpress Sox2 as well as Sox9. Sox9 was required for spheroid growth, and overexpression increased invasiveness and neural features of prostate cancer cells. Sox9 was transiently upregulated in castration-induced progression of prostate cancer xenografts and was specifically overexpressed in neoadjuvant hormone therapy (NHT)-treated patient tumors. High Sox9 expression in NHT-treated patients predicts biochemical recurrence. Finally, we link Sox9 induction to NF-κB dimer activation in prostate cancer cells.

Conclusions: Developmentally reprogrammed prostate cancer cell models recapitulate features of clinically advanced prostate tumors, including downregulated Rb1/p53 and overexpression of Sox2 with Sox9. Sox9 is a marker of a transitional state that identifies prostate cancer cells under the stress of therapeutic assault and facilitates progression to therapy resistance. Its expression may index the relative activity of the NF-κB pathway.
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http://dx.doi.org/10.1158/1078-0432.CCR-19-0098DOI Listing
April 2020

A polymeric paste-drug formulation for intratumoral treatment of prostate cancer.

Prostate Cancer Prostatic Dis 2020 06 25;23(2):324-332. Epub 2019 Nov 25.

Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada.

Objective: Focal therapy has emerged as a treatment option for low- to intermediate-risk localized prostate cancer (PCa) patients, to balance the risks for urinary and sexual morbidity of radical treatment with the psychological burden of active surveillance. In this context, we developed ST-4PC, an injectable, polymeric paste formulation containing docetaxel (dtx) and bicalutamide (bic) for image-guided focal therapy of PCa. The objective of this work was to evaluate the in vitro characteristics and in vivo toxicity and efficacy of ST-4PC.

Material And Methods: In vitro drug release was evaluated using high-performance liquid chromatography. In vivo toxicity of blank- and drug-loaded ST-4PC was assessed in mice and rats. Tumor growth inhibition was evaluated in LNCaP subcutaneous (s.c.) and LNCaP-luc orthotopic xenograft models. Using the s.c. model, mice were monitored weekly for weight loss, tumor volume (TV) and serum PSA. For the orthotopic model, mice were additionally monitored for bioluminescence as measure of tumor growth.

Results: ST-4PC demonstrated a sustained and steady release of incorporated drugs with 50% dtx and 20% bic being released after 14 days. While no systemic toxicity was observed, dose-dependent local side effects from dtx developed in the s.c. but not in the orthotopic model, illustrating the limitations of s.c. models for evaluating local cytotoxic therapy. In the s.c. model, 0.1%/4% and 0.25%/4% dtx/bic ST-4PC paste significantly reduced PSA progression, but did not have a significant inhibitory effect on TV. ST-4PC loaded with 1%/4% dtx/bic significantly reduced TV, serum PSA, and bioluminescence in the orthotopic xenograft model. Compared with drugs dissolved in DMSO, ST-4PC significantly delayed tumor growth.

Conclusion: Image-guided focal therapy using ST-4PC demonstrated promising inhibition of PSA progression and orthotopic tumor growth in vivo without significant toxicity, and warrants further clinical evaluation.
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http://dx.doi.org/10.1038/s41391-019-0190-xDOI Listing
June 2020
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