Citations

Abstract Treatment of glioblastoma multiforme (GBM) continues to be a challenge due to its infiltrative nature, tumor heterogeneity, and lack of therapeutic agents that penetrate the blood-brain barrier (BBB). While the primary tumor is permeable to some degree, the ability of GBM cells to invade areas of parenchyma with an intact BBB indicates development of BBB-penetrable compounds is a necessity. The multifunctional protein MDM2 holds promise as a therapeutic target in a variety of cancers and plays a critical role in controlling cell survival, invasion, and DNA repair. MDM2 antagonists such as nutlin3a and RG7112 are being used to interrogate the impact of modulating MDM2 function in combination with front-line therapy. Our objective was to investigate whether MDM2 antagonists, alone or in combination with temozolomide (TMZ), can augment cell death in orthotopic GBM xenograft models. In vitro data indicate that TMZ and nutlin3a are synergistic in decreasing cell viability in wild type (wt) p53 U87-MG, primary human wt p53 GBM10 and mutant (mt) p53 GBM43 cells. Pharmacodynamic studies demonstrated that the mechanism of action for promoting cell death following exposure to TMZ/nutlin3a was multifactorial. Comet assays indicated that repair of TMZ-mediated DNA damage was significantly delayed in wt and mt p53 GBM cells treated with TMZ/nutlin3a compared to TMZ alone and the base excision repair protein Ape1 was downregulated in cells treated with TMZ/nutlin3a. Pharmacokinetic studies guided development of rational dosing regimens in which 2-3 five-day cycles of TMZ followed by nutlin3a 4 hours later were investigated. In ectopic U87-MG xenografts, nutlin3a sensitized xenografts to TMZ-mediated cell death. Orthotopic studies employing U87-MG, GBM10, and GBM43 tumors are being utilized to determine if nutlin3a levels detectable in the brain via HPLC-MS/MS(API 4000) are sufficient to modulate MDM2 function in the context of TMZ and increase survival. In the TMZ-resistant GBM10 (wtp53, MGMTpos, and PTENnull) orthotopic model, there was a modest increase in median survival from 63 days with TMZ to 73 days with TMZ/nutlin3a. Higher and more sustained brain levels of MDM2 antagonists will likely be necessary to improve survival. The MDM2 antagonist RG7112 has an improved PK profile and structural analysis of RG7112 and nutlin3a via QikProp 3.0 (www.schrodinger.com) indicates that RG7112 also has an improved predicted brain/blood partition coefficient (plog BB) compared to nutlin3a (RG7112 = -0.17; nutlin3a = -0.415). Studies are in progress to assess the brain penetration of RG7112 and its effect on GBM growth in vivo. Taken together, our data suggest that modulation of MDM2 function in the context of cytotoxic therapy has the potential to alter mechanisms involved in DNA repair that can promote cell death and improve survival. Citation Format: Haiyan Wang, Shanbao Cai, Barbara J. Bailey, Lawrence M. Gelbert, M. Reza Saadatzadeh, Aaron A. Cohen-Gadol, Jann N. Sarkaria, Paul Territo, Taxiarchis M. Georgiadis, T. Zachary Gunter, Samy Meroueh, Eric C. Long, David R. Jones, Lindsey D. Mayo, Shannon Harlan, Karen E. Pollok. Sensitization of temozolomide-mediated glioblastoma cell death by targeting MDM2: Assessment of PD biomarkers, brain penetration, and efficacy in humanized orthotopic xenograft models. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2741. doi:10.1158/1538-7445.AM2014-2741

Background— Long-QT syndrome (LQTS) may result in syncope, seizures, or sudden cardiac arrest. Although 16 LQTS-susceptibility genes have been discovered, 20% to 25% of LQTS remains genetically elusive. Methods and Results— We performed whole-exome sequencing child–parent trio analysis followed by recessive and sporadic inheritance modeling and disease-network candidate analysis gene ranking to identify a novel underlying genetic mechanism for LQTS. Subsequent mutational analysis of the candidate gene was performed with polymerase chain reaction, denaturing high-performance liquid chromatography, and DNA sequencing on a cohort of 33 additional unrelated patients with genetically elusive LQTS. After whole-exome sequencing and variant filtration, a homozygous p.D18fs*13 TRDN -encoded triadin frameshift mutation was discovered in a 10-year-old female patient with LQTS with a QTc of 500 milliseconds who experienced recurrent exertion-induced syncope/cardiac arrest beginning at 1 year of age. Subsequent mutational analysis of TRDN revealed either homozygous or compound heterozygous frameshift mutations in 4 of 33 unrelated cases of LQTS (12%). All 5 TRDN-null patients displayed extensive T-wave inversions in precordial leads V 1 through V 4 , with either persistent or transient QT prolongation and severe disease expression of exercise-induced cardiac arrest in early childhood (≤3 years of age) and required aggressive therapy. The overall yield of TRDN mutations was significantly greater in patients ≤10 years of age (5 of 10, 50%) compared with older patients (0 of 24, 0%; P =0.0009). Conclusions— We identified TRDN as a novel underlying genetic basis for recessively inherited LQTS. All TRDN-null patients had strikingly similar phenotypes. Given the recurrent nature of potential lethal arrhythmias, patients fitting this phenotypic profile should undergo cardiac TRDN genetic testing.

Background— A 2% to 5% background rate of rare SCN5A nonsynonymous single nucleotide variants (nsSNVs) among healthy individuals confounds clinical genetic testing. Therefore, the purpose of this study was to enhance interpretation of SCN5A nsSNVs for clinical genetic testing using estimated predictive values derived from protein-topology and 7 in silico tools. Methods and Results— Seven in silico tools were used to assign pathogenic/benign status to nsSNVs from 2888 long-QT syndrome cases, 2111 Brugada syndrome cases, and 8975 controls. Estimated predictive values were determined for each tool across the entire SCN5A -encoded Na v 1.5 channel as well as for specific topographical regions. In addition, the in silico tools were assessed for their ability to correlate with cellular electrophysiology studies. In long-QT syndrome, transmembrane segments S3–S5+S6 and the DIII/DIV linker region were associated with high probability of pathogenicity. For Brugada syndrome, only the transmembrane spanning domains had a high probability of pathogenicity. Although individual tools distinguished case- and control-derived SCN5A nsSNVs, the composite use of multiple tools resulted in the greatest enhancement of interpretation. The use of the composite score allowed for enhanced interpretation for nsSNVs outside of the topological regions that intrinsically had a high probability of pathogenicity, as well as within the transmembrane spanning domains for Brugada syndrome nsSNVs. Conclusions— We have used a large case/control study to identify regions of Na v 1.5 associated with a high probability of pathogenicity. Although topology alone would leave the variants outside these identified regions in genetic purgatory, the synergistic use of multiple in silico tools may help promote or demote a variant’s pathogenic status.

ObjectivesTo evaluate the differences in estimated glomerular filtration rate decline by urinary diversion type (incontinent diversion vs continent diversion) and preoperative estimated glomerular filtration rate among patients undergoing radical cystectomy and urinary diversion.MethodsWe evaluated 1383 patients treated with radical cystectomy between 1980–2006 who had a preoperative estimated glomerular filtration rate of 45‐89 mL/min/1.73 m2. Estimated glomerular filtration rate was estimated using Chronic Kidney Disease Epidemiology Collaboration equations, and patients were stratified by preoperative estimated glomerular filtration rate into chronic kidney disease 2 (estimated glomerular filtration rate 60–89 mL/min/1.73 m2) and chronic kidney disease 3a (estimated glomerular filtration rate 45–59 mL/min/1.73 m2). Multiple definitions of estimated glomerular filtration rate decline were evaluated: (i) 10‐point decline in estimated glomerular filtration rate; (ii) 20% decline in estimated glomerular filtration rate; and (iii) 10% decline in estimated glomerular filtration rate. Time to estimated glomerular filtration rate decline was compared using the Kaplan–Meier method stratified by diversion type. Cox regression models were used to evaluate the association of diversion type with estimated glomerular filtration rate decline risk.ResultsIn total, 74% (1021/1383) of patients underwent incontinent diversion and 26% (362/1383) underwent continent diversion. Preoperative chronic kidney disease 2 and chronic kidney disease 3a were noted among 59% and 41% of patients who underwent incontinent diversion, versus 74% and 26% with continent diversion. Median follow up after RC was 11.2 years. The rate of estimated glomerular filtration rate decline in patients with incontinent diversion versus continent diversion was similar when stratified by preoperative chronic kidney disease 2 and preoperative chronic kidney disease 3a, regardless of estimated glomerular filtration rate decline definition. On multivariable analysis, continent diversion was not associated with estimated glomerular filtration rate decline for patients with preoperative chronic kidney disease 3a.ConclusionsThe risk of estimated glomerular filtration rate decline over 10 years was not significantly different after incontinent diversion versus continent diversion among patients with preoperative chronic kidney disease 2 or chronic kidney disease 3a. Continent diversion does not appear to confer an independently increased risk of estimated glomerular filtration rate decline in patients with preoperative chronic kidney disease 3a.

Objective There is a paucity of data on the impact of complete revascularisation (CR) following percutaneous coronary intervention (PCI) among patients with diabetes with multivessel coronary disease. In this study, we assess the impact of CR, using a relatively simple anatomical definition, on long-term outcomes (median follow-up 7.9 years) in patients with diabetes, and compare with patients without diabetes. Methods 5350 patients with multivessel disease (coronary stenoses ≥70% in ≥2 major epicardial arteries) who underwent PCI between January 1997 and June 2011 were included. Patients were divided into 4 groups according to diabetes and CR status (absence of residual coronary stenosis in major, predominantly proximal, epicardial segments according to Coronary Artery Surgery Study (CASS) classification). Results Patients with diabetes and patients with incomplete revascularisation (IR) had more adverse clinical and angiographic characteristics. IR was frequent in patients with diabetes, and was marginally more common than in patients without diabetes (47% vs 44%, p<0.001). Patients with diabetes and patients without diabetes had higher mortality rates after IR than after CR (HR 1.56 (95% CI (1.39 to 1.85), p<0.001 for patients with diabetes and 1.70 (95% CI (1.50 to 1.92), p<0.001) in patients without diabetes). However, the absolute risk was higher for patients with diabetes (5-year mortality: IR 35.8%, CR 21.2%) than in patients without diabetes (5-year mortality: IR 22.2%, CR 14.1%). In a multivariable model, IR and diabetes mellitus were independent predictors of total mortality. This effect was present in the bare metal stent and drug-eluting stent eras and in patients with stable disease and acute coronary syndromes. Conclusions CR is associated with lower long-term mortality in patients with diabetes and patients without diabetes. However the difference was significantly greater in patients with diabetes compared with patients without diabetes.

Abstract Background Objective cost estimates and source of cost differences are needed across the spectrum of cognition, including cognitively normal (CN), mild cognitive impairment (MCI), newly discovered dementia, and prevalent dementia. Methods Subjects were a subset of the Mayo Clinic Study of Aging stratified‐random sampling of Olmsted County, MN, residents aged 70 to 89 years. A neurologist reviewed provider‐linked medical records to identify prevalent dementia (review date = index). Remaining subjects were invited to participate in prospective clinical/neuropsychological assessments; participants were categorized as CN, MCI, or newly discovered dementia (assessment date = index). Costs for medical services/procedures 1‐year pre‐index (excluding indirect and long‐term care costs) were estimated using line‐item provider‐linked administrative data. We estimated contributions of care‐delivery site and comorbid conditions (including and excluding neuropsychiatric diagnoses) to between‐category cost differences. Results Annual mean medical costs for CN, MCI, newly discovered dementia, and prevalent dementia were $6042, $6784, $9431, $11,678, respectively. Hospital inpatient costs contributed 70% of total costs for prevalent dementia and accounted for differences between CN and both prevalent and newly discovered dementia. Ambulatory costs accounted for differences between CN and MCI. Age‐, sex‐, education‐adjusted differences reached significance for CN versus newly discovered and prevalent dementia and for MCI versus prevalent dementia. After considering all comorbid diagnoses, between‐category differences were reduced (e.g., prevalent dementia minus MCI (from $4842 to $3575); newly discovered dementia minus CN (from $3578 to $711)). Following the exclusion of neuropsychiatric diagnoses from comorbidity adjustment, between‐category differences tended to revert to greater differences. Conclusions Cost estimates did not differ significantly between CN and MCI. Substantial differences between MCI and prevalent dementia reflected high inpatient costs for dementia and appear partly related to co‐occurring mental disorders. Such comparisons can help inform models aimed at identifying where, when, and for which individuals proposed interventions might be cost‐effective.

Objective To assess the impact of primary or progressive status on recurrence‐free survival ( RFS ), cancer‐specific mortality ( CSM ) and overall mortality ( OM ) after radical cystectomy ( RC ) for muscle‐ invasive bladder cancer ( MIBC ). Patients and Methods A total of 768 consecutive patients underwent RC as treatment for MIBC at our institution between 2000 and 2012. Primary MIBC was defined as no previous history of bladder cancer and progressive was defined as recorded previous treated non‐ MIBC ( NMIBC ) that had progressed to MIBC . The median follow‐up was 85 (60–109) months. Univariate and multivariate Cox regression models were used to compare RFS , CSM and OM between these two cohorts. Results In all, 475 (61.8%) patients had primary and 293 (38.2%) patients had progressive MIBC . There were no differences between the two groups in terms of demographics, pathological and peri‐operative complications (all P > 0.1). The 10‐year RFS , CSM and OM rates for primary vs progressive status were 43 vs 36% ( P = 0.01), 43 vs 37% ( P = 0.01), and 35 vs 28% ( P = 0.03), respectively. On multivariable Cox regression analyses, progressive status remained significantly associated with a higher rate of recurrence (hazard ratio [ HR ] 1.47, 95% confidence interval [ CI ] 1.12–1.79; P = 0.03), CSM ( HR 1.42, 95% CI 1.07–1.89; P = 0.01) and OM ( HR 1.42, 95% CI 1.13–1.65; P = 0.02). Conclusions Among patients treated with RC for MIBC , progressive status was associated with a higher CSM , OM and recurrence rate after RC . The present study thus provides an impetus to improve risk sub‐stratification when bladder cancer is still at the NMIBC stage, be it through new biomarkers or improved imaging, as a subset of patients with NMIBC are likely to benefit from early RC .