Citations

AbstractPIK3CA is one of the most frequently mutated genes in human cancers, with the two most prevalent activating mutations being E545K and H1047R. Although the altered intracellular signaling pathways in these cells have been described, the effect of these mutations on their extracellular vesicles (EVs) has not yet been reported. To study altered cellular physiology and intercellular communication through proteomic analysis of EVs, MCF10A cells and their isogenic mutant versions (PIK3CA E545K and H1047R) were cultured and their EVs enriched by differential ultracentrifugation. Proteins were extracted, digested with trypsin and the peptides labeled with tandem mass tag (TMT) reagents and analyzed by liquid chromatography tandem mass spectrometry (LC‐MS/MS). Four thousand six hundred and fifty‐five peptides were identified from 579 proteins of which 522 proteins have been previously described in EVs. Relative quantitation revealed altered levels of EV proteins including several cell adhesion molecules. Mesothelin, E‐cadherin, and epithelial cell adhesion molecule were elevated in both mutant cell‐derived EVs. Markers of tumor invasion and progression like galectin‐3 and transforming growth factor beta induced protein were increased in both mutants. Overall, activating mutations in PIK3CA result in altered EV composition with characteristic changes associated with these hotspot mutations.

LINKED CONTENTThis article is linked to Quinn et al papers. To view these articles, visit https://doi.org/10.1111/apt.16859 and https://doi.org/10.1111/apt.16954

Abstract Prostate-specific antigen (PSA) is widely used clinically for prostate cancer diagnostics and as an indicator of therapeutic efficacy and recurrence. Several human chemoprevention trials are being conducted to validate the prostate cancer prevention efficacy of selenium and PSA is used in these trials as a biomarker of response. A better understanding of the effects of selenium metabolites on the kinetics of PSA turnover and secretion in prostate cancer cells treated with selenium at concentrations which are achievable physiologically will be important for interpreting the results of these trials. This study addresses whether the putative active anticancer selenium metabolite methylselenol or its precursor methylseleninic acid (MSeA) specifically inhibits PSA expression in the androgen-responsive LNCaP prostate cancer cell model. The results show that exposure to sub-apoptotic concentrations of MSeA and methylselenol inhibited PSA protein expression and secretion, whereas sodium selenite and selenomethionine lacked inhibitory effect. The inhibition was detectable at 3 h of exposure and required a threshold level of MSeA to sustain. Turnover experiments showed that MSeA caused rapid PSA degradation, which was partially blocked by lysosomal inhibitors, but not by a proteasomal inhibitor. Furthermore, MSeA treatment reduced PSA mRNA level, down-regulated androgen receptor protein expression, and inhibited androgen-stimulated PSA promoter transcription. In summary, methylselenol or MSeA specifically and rapidly inhibited PSA expression through two mechanisms of action: inducing PSA protein degradation and suppressing androgen-stimulated PSA transcription. These findings may have important mechanistic implications for the prostate specific cancer chemopreventive action of selenium.

AbstractBackgroundSudden cardiac death (SCD) is common after orthotopic heart transplant (OHT). No clear guidelines for implantable cardioverter defibrillator (ICD) implantation in OHT patients at high risk for SCD currently exist.ObjectivesTo assess the safety, efficacy, and benefit of ICDs and resynchronization therapy post‐OHT. We also provide a systematic review of previous reports.MethodsA retrospective multicenter cohort study within the United States. Patients with ICD post‐OHT between 2000 and 2020 were identified.ResultsWe analyzed 16 patients from 4 centers. The mean standard‐deviation (SD) age was 43 (18) years at OHT and 51 (20) years at ICD implantation. The mean (SD) duration from OHT to ICD implantation was 9 (5) years. The mean (SD) left ventricular ejection fraction (LVEF) was 35% (17%). There were 2 (13%) postprocedural complications: 1 hematoma and 1 death. Mean (SD) follow‐up was 24 (23) months. Survival rate was 63% (10/16) at 1 year and 56% (9/16) at 2 years, with 6/7 of those who died having LVEF < 35% at the time of the ICD implantation. Patients were more likely to receive appropriate therapy if their ICD was implanted for secondary (5/8) rather than primary (0/8) prevention (p = .007). Of those who did, 4 patients survived to 30 days post‐ICD therapy. Severe CAV was not associated with the rate of appropriate therapy.ConclusionsBeneficial outcomes were observed when ICDs were implanted for secondary prevention only, and in patients with higher baseline LVEF. We also observed benefits with resynchronization therapy.

Background: The study of hypertrophic cardiomyopathy (HCM) can yield insight into the mechanisms underlying the complex trait of cardiac hypertrophy. To date, most genetic variants associated with HCM have been found in sarcomeric genes. Here, we describe a novel HCM-associated variant in the noncanonical Wnt signaling interactor WTIP (Wilms tumor interacting protein) and provide evidence of a role for WTIP in complex disease. Methods: In a family affected by HCM, we used exome sequencing and identity-by-descent analysis to identify a novel variant in WTIP (p.Y233F). We knocked down WTIP in isolated neonatal rat ventricular myocytes with lentivirally delivered short hairpin ribonucleic acids and in Danio rerio via morpholino injection. We performed weighted gene coexpression network analysis for WTIP in human cardiac tissue, as well as association analysis for WTIP variation and left ventricular hypertrophy. Finally, we generated induced pluripotent stem cell–derived cardiomyocytes from patient tissue, characterized size and calcium cycling, and determined the effect of verapamil treatment on calcium dynamics. Results: WTIP knockdown caused hypertrophy in neonatal rat ventricular myocytes and increased cardiac hypertrophy, peak calcium, and resting calcium in D rerio . Network analysis of human cardiac tissue indicated WTIP as a central coordinator of prohypertrophic networks, while common variation at the WTIP locus was associated with human left ventricular hypertrophy. Patient-derived WTIP p.Y233F-induced pluripotent stem cell–derived cardiomyocytes recapitulated cellular hypertrophy and increased resting calcium, which was ameliorated by verapamil. Conclusions: We demonstrate that a novel genetic variant found in a family with HCM disrupts binding to a known Wnt signaling protein, misregulating cardiomyocyte calcium dynamics. Further, in orthogonal model systems, we show that expression of the gene WTIP is important in complex cardiac hypertrophy phenotypes. These findings, derived from the observation of a rare Mendelian disease variant, uncover a novel disease mechanism with implications across diverse forms of cardiac hypertrophy.

e18544 Background: Underrepresented minority (URM) patients continue to make up a small percentage of patients treated on cancer clinical trials (CCTs), thus perpetuating health care disparities. Research indicates that engagement of healthcare staff is critical for successful recruitment. Our study sought to better define barriers to minority recruitment to CCT from the research staff perspective. Methods: Semi-structured qualitative interviews were conducted of key stakeholders for CCT enrollment, including clinical research coordinators (CRCs), principal investigators (PIs), and treating clinicians. Questions for the healthcare team explored their experiences caring for URM patients with specific inquiry into the barriers of enrollment/retention and the processes or resources required to better meet patient needs. Results: All hematology and oncology staff at Mayo Clinic Cancer Center were invited to participate via email. Of the 28 who consented, 13 were male (46%), 15 female (54%), and 21% non-white (3 Asian, 2 Hispanic, 1 Black). Of the 19 PIs, 9 were Professors (47%), 5 Associate professors (26%), and 5 Assistant professors (26%). The additional 9 interviewees were CRCs. Select themes with representative quotes and proposed actions can be seen in Table. Conclusions: Recommendations for CCT accrual include accelerating efforts to address workforce diversity gaps, engaging in community outreach, optimization of CCT participation through collaborative care, incentivizing trial participation, and creating flexibility in eligibility criteria.[Table: see text]

e18543 Background: Representation of minority patients (pts) in cancer clinical trials (CCTs) is low and contributes to health disparities. Our study sought to understand the beliefs and motivations of minority patients and to identify barriers and facilitators of CCT enrollment. Methods: 270 minority pts treated on CCT were identified from the medical record from 2018-2021. Of the 138 of pts alive, 13 (9.4%) consented. Semi-structured qualitative interviews were conducted exploring motivations, barriers, and facilitators to CCT participation. Surveys collected demographics and explored beliefs towards cancer and factors that influenced participation. Results: Of the 13 participants, 9 were female (69%), 4 Hispanic (30%), 3 Black (23%), 3 multiple races (23%), 2 Asian (15%), 2 Native American (15%), and 1 Native Hawaiian (8%). Two pts had a high school education (15%), 7 ≥ 4-year college (54%), 4 ≥ 2-year college (30%). Eight pts were married, 3 divorced, 1 widowed, and 1 single. Employment status was: employed (4 pts, 30%), unemployed (1 pt, 8%), disabled (5 pts, 38%), retired (3 pts, 23%). All pts were insured. Median household was 3 people (range 1 to > 5); 3 pts had dependents. 9 pts had their own vehicle; 4 used public or subsidized transport. 2 pts had trouble finding transportation. Income was: 3 pts < 25K, 4 pts 25-35K, 1 pts 35-50 K, 1 pts 50-75K, and 4 pts > 75K. 4 pts received emotional support from religion. All pts had heard of CCTs and 6 (46%) had known other CT participants. Direct communication from healthcare provider was the most common way of hearing about CCT. 9 pts (69%) had trust or strong trust in experimental therapy/CCT; 4 pts (30%) were neutral. 8 pts (61%) believed standard therapy was needed to cure cancer. 5 pts (38%) believed God would decide if they die from cancer. 7 pts (54%) believed that worry makes cancer worse. Key themes about patients’ motivation to participate: chance for cure, staying positive, giving back to others, having representation in research, and advancing science. Key themes about facilitators to participation: supportive family, cost coverage for treatment, and limited treatment options. Key themes on participation: minimizing logistical barriers, decentralizing CCTs, increasing awareness via patient narratives, diversifying research staff, minimizing cost, and being clear on purpose and benefit of CCT. Factors from survey that influenced participation are summarized in Table. Conclusions: Understanding minority pts experience through in-depth interviews is valuable and may help with recruitment.[Table: see text]

Background: Haemorrhagic demyelinating lesions are rare, and little is known about the demyelinating diseases with which they are associated, or how lesional haemorrhage affects treatment and outcomes. Objective: To examine the clinical characteristics and outcomes of patients with demyelinating lesions and magnetic resonance imaging (MRI) evidence of haemorrhage seen at the Mayo clinic between 1990 and 2018. Methods: The Mayo Clinic’s medical-record diagnostic-linkage system was used to identify patients with CNS demyelinating disease and parenchymal haemorrhage on brain MRI cross-referenced against a database of patients with pathologically confirmed CNS demyelinating disease. The clinical characteristics, diagnosis, MRI findings, brain histopathology, and outcomes of these patients were reviewed. Results: Ten patients with haemorrhagic demyelination were identified, including three patients who underwent a brain biopsy. The main findings were that haemorrhagic demyelinating lesions most often occur in atypical forms of demyelination, especially acute haemorrhagic leukoencephalitis (AHL, or Weston–Hurst disease) and tumefactive demyelination, and rarely in multiple sclerosis. A spectrum of outcomes was observed for these patients ranging from complete remission through to high level disability. Conclusion: Lesional haemorrhage is uncommon in demyelinating disease where it is most closely associated with AHL. Bleeding within a demyelinating lesion does not always herald a poor prognosis.

Abstract Background: Atrial fibrillation (AF) is relatively less frequent in younger patients (age<50). Recently, studies have suggested that early restoration of sinus rhythm may lead to improved outcomes compared with rate control. Methods: We included all hospitalized patients between 18 and 50 years with a diagnosis of AF from the Nationwide Readmission Database 2016-2017 from the Healthcare Cost and Utilization Project. Demographic and comorbidity data were collected and analyzed. Outcomes assessed included one-year AF readmission rates, all-cause readmission, ischemic stroke, and all-cause mortality. Subgroup analyses were performed for all demographic and comorbidity variables.Results: Overall, 52,598 patients (medium age 44, interquartile range 38-48, female 25.7%) were included in the study, including 2,146 (4.0%) who underwent catheter ablation for AF. Patients who underwent catheter ablation had a significantly lower rate of readmission for AF or any cause at one year (adjusted hazard ratios (HR) of 0.52 [95% confidence interval (CI): 0.43-0.63] and HR of 0.81 [95% CI: 0.72 - 0.89], respectively). There was no difference in 1-year readmission for stroke or all-cause mortality between the two groups. Subgroup analyses showed a consistent reduction in the risk of AF readmission among major demographic and comorbidity subgroups.Conclusion: Catheter ablation in young patients with AF was associated with a reduction in 1-year AF related and all-cause readmissions. These data merit further prospective investigation for validation.

LINKED CONTENTThis article is linked to Quinn et al papers. To view these articles, visit https://doi.org/10.1111/apt.16859 and https://doi.org/10.1111/apt.16916