Autophagy cooperates with PDGFRA to support oncogenic growth signaling.

Macroautophagy (referred to as autophagy hereafter) is a highly conserved catabolic process which sequesters intracellular substrates for lysosomal degradation. Autophagy-related proteins have been shown to be involved in various aspects of tumor development by engaging with multiple cellular substrates. We recently uncovered a novel role for autophagy in regulating the signaling and levels of PDGFRA, a receptor tyrosine kinase amplified in several cancers. We discovered that PDGFRA can be targeted to autophagic degradation by binding the autophagy cargo receptor SQSTM1. Surprisingly, PDGFRA-mediated signaling is perturbed in the absence of autophagy despite enhanced receptor levels. We show that this is due to disrupted trafficking of the receptor to late endosomes where signaling activity persists. Conversely, prolonged autophagy inhibition results in a transcriptional downregulation of Pdgfra as a result of inhibited signaling activity demonstrating that short- and long-term autophagy inhibition have opposing effects on receptor levels. We further investigated the consequence of PDGFRA regulation by autophagy using a mouse model for gliomagenesis where we observed a disruption in PDGFA-driven tumor formation when autophagy is inhibited. Activation of downstream signaling through Pten mutation overrides the need for autophagy during tumor development suggesting a genotype-specific role for autophagy during tumorigenesis. Altogether, our findings provide a novel mechanism through which autophagy can support tumor growth.

Autophagy supports PDGFRA-dependent brain tumor development by enhancing oncogenic signaling.

Autophagy is a conserved cellular degradation process. While autophagy-related proteins were shown to influence the signaling and trafficking of some receptor tyrosine kinases, the relevance of this during cancer development is unclear. Here, we identify a role for autophagy in regulating platelet-derived growth factor receptor alpha (PDGFRA) signaling and levels. We find that PDGFRA can be targeted for autophagic degradation through the activity of the autophagy cargo receptor p62. As a result, short-term autophagy inhibition leads to elevated levels of PDGFRA but an unexpected defect in PDGFA-mediated signaling due to perturbed receptor trafficking. Defective PDGFRA signaling led to its reduced levels during prolonged autophagy inhibition, suggesting a mechanism of adaptation. Importantly, PDGFA-driven gliomagenesis in mice was disrupted when autophagy was inhibited in a manner dependent on Pten status, thus highlighting a genotype-specific role for autophagy during tumorigenesis. In summary, our data provide a mechanism by which cells require autophagy to drive tumor formation.

Incremental prognostic value of biomarkers in PARADIGM-HF.

AIMS: It is uncertain how much candidate biomarkers improve risk prediction when added to comprehensive models including routinely collected clinical and laboratory variables in heart failure. METHODS AND RESULTS: Aldosterone, cystatin C, high-sensitivity troponin T (hs-TnT), galectin-3, growth differentiation factor-15 (GDF-15), kidney injury molecule-1, matrix metalloproteinase-2 and -9, soluble suppression of tumourigenicity-2, tissue inhibitor of metalloproteinase-1 (TIMP-1) and urinary albumin to creatinine ratio were measured in 1559 of PARADIGM-HF participants. We tested whether these biomarkers, individually or collectively, improved the performance of the PREDICT-HF prognostic model, which includes clinical, routine laboratory, and natriuretic peptide data, for the primary endpoint and cardiovascular and all-cause mortality. The mean age of participants was 67.3 ± 9.9 years, 1254 (80.4%) were men and 1103 (71%) were in New York Heart Association class II. During a mean follow-up of 30.7 months, 300 patients experienced the primary outcome and 197 died. Added individually, only four biomarkers were independently associated with all outcomes: hs-TnT, GDF-15, cystatin C and TIMP-1. When all biomarkers were added simultaneously to the PREDICT-HF models, only hs-TnT remained an independent predictor of all three endpoints. GDF-15 also remained predictive of the primary endpoint; TIMP-1 was the only other predictor of both cardiovascular and all-cause mortality. Individually or in combination, these biomarkers did not lead to significant improvements in discrimination or reclassification. CONCLUSIONS: None of the biomarkers studied individually or collectively led to a meaningful improvement in the prediction of outcomes over what is provided by clinical, routine laboratory, and natriuretic peptide variables.

Temozolomide sensitivity of malignant glioma cell lines - a systematic review assessing consistencies between in vitro studies.

BACKGROUND: Malignant glioma cell line models are integral to pre-clinical testing of novel potential therapies. Accurate prediction of likely efficacy in the clinic requires that these models are reliable and consistent. We assessed this by examining the reporting of experimental conditions and sensitivity to temozolomide in glioma cells lines. METHODS: We searched Medline and Embase (Jan 1994-Jan 2021) for studies evaluating the effect of temozolomide monotherapy on cell viability of at least one malignant glioma cell line. Key data items included type of cell lines, temozolomide exposure duration in hours (hr), and cell viability measure (IC50). RESULTS: We included 212 studies from 2789 non-duplicate records that reported 248 distinct cell lines. The commonest cell line was U87 (60.4%). Only 10.4% studies used a patient-derived cell line. The proportion of studies not reporting each experimental condition ranged from 8.0-27.4%, including base medium (8.0%), serum supplementation (9.9%) and number of replicates (27.4%). In studies reporting IC50, the median value for U87 at 24 h, 48 h and 72 h was 123.9 µM (IQR 75.3-277.7 µM), 223.1 µM (IQR 92.0-590.1 µM) and 230.0 µM (IQR 34.1-650.0 µM), respectively. The median IC50 at 72 h for patient-derived cell lines was 220 µM (IQR 81.1-800.0 µM). CONCLUSION: Temozolomide sensitivity reported in comparable studies was not consistent between or within malignant glioma cell lines. Drug discovery science performed on these models cannot reliably inform clinical translation. A consensus model of reporting can maximise reproducibility and consistency among in vitro studies.

Invasive versus medically managed acute coronary syndromes with prior bypass (CABG-ACS): insights into the registry versus randomised trial populations.

BACKGROUND: Coronary artery bypass graft (CABG) patients are under-represented in acute coronary syndrome (ACS) trials. We compared characteristics and outcomes for patients who did and did not participate in a randomised trial of invasive versus non-invasive management (CABG-ACS). METHODS: ACS patients with prior CABG in four hospitals were randomised to invasive or non-invasive management. Non-randomised patients entered a registry. Primary efficacy (composite of all-cause mortality, rehospitalisation for refractory ischaemia/angina, myocardial infarction (MI), heart failure) and safety outcomes (composite of bleeding, stroke, procedure-related MI, worsening renal function) were independently adjudicated. RESULTS: Of 217 patients screened, 84 (39%) screenfailed, of whom 24 (29%) did not consent and 60 (71%) were ineligible. Of 133 (61%) eligible, 60 (mean±SD age, 71±9 years, 72% male) entered the trial and 73 (age, 72±10 years, 73% male) entered a registry (preferences: physician (79%), patient (38%), both (21%)).Compared with trial participants, registry patients had more valve disease, lower haemoglobin, worse New York Heart Association class and higher frailty.At baseline, invasive management was performed in 52% and 49% trial and registry patients, respectively, of whom 32% and 36% had percutaneous coronary intervention at baseline, respectively (p=0.800). After 2 years follow-up (694 (median, IQR 558-841) days), primary efficacy (43% trial vs 49% registry (HR 1.14, 95% CI 0.69 to 1.89)) and safety outcomes (28% trial vs 22% registry (HR 0.74, 95% CI 0.37 to 1.46)) were similar. EuroQol was lower in registry patients at 1 year. CONCLUSIONS: Compared with trial participants, registry participants had excess morbidity, but longer-term outcomes were similar. TRIAL REGISTRATION NUMBER: NCT01895751.

The impact of autophagy during the development and survival of glioblastoma.

Glioblastoma is the most common and aggressive adult brain tumour, with poor median survival and limited treatment options. Following surgical resection and chemotherapy, recurrence of the disease is inevitable. Genomic studies have identified key drivers of glioblastoma development, including amplifications of receptor tyrosine kinases, which drive tumour growth. To improve treatment, it is crucial to understand survival response processes in glioblastoma that fuel cell proliferation and promote resistance to treatment. One such process is autophagy, a catabolic pathway that delivers cellular components sequestered into vesicles for lysosomal degradation. Autophagy plays an important role in maintaining cellular homeostasis and is upregulated during stress conditions, such as limited nutrient and oxygen availability, and in response to anti-cancer therapy. Autophagy can also regulate pro-growth signalling and metabolic rewiring of cancer cells in order to support tumour growth. In this review, we will discuss our current understanding of how autophagy is implicated in glioblastoma development and survival. When appropriate, we will refer to findings derived from the role of autophagy in other cancer models and predict the outcome of manipulating autophagy during glioblastoma treatment.

Targeting of early endosomes by autophagy facilitates EGFR recycling and signalling.

Despite recently uncovered connections between autophagy and the endocytic pathway, the role of autophagy in regulating endosomal function remains incompletely understood. Here, we find that the ablation of autophagy-essential players disrupts EGF-induced endocytic trafficking of EGFR. Cells lacking ATG7 or ATG16L1 exhibit increased levels of phosphatidylinositol-3-phosphate (PI(3)P), a key determinant of early endosome maturation. Increased PI(3)P levels are associated with an accumulation of EEA1-positive endosomes where EGFR trafficking is stalled. Aberrant early endosomes are recognised by the autophagy machinery in a TBK1- and Gal8-dependent manner and are delivered to LAMP2-positive lysosomes. Preventing this homeostatic regulation of early endosomes by autophagy reduces EGFR recycling to the plasma membrane and compromises downstream signalling and cell survival. Our findings uncover a novel role for the autophagy machinery in maintaining early endosome function and growth factor sensing.

Invasive Versus Medical Management in Patients With Prior Coronary Artery Bypass Surgery With a Non-ST Segment Elevation Acute Coronary Syndrome.

BACKGROUND: The benefits of routine invasive management in patients with prior coronary artery bypass grafts presenting with non-ST elevation acute coronary syndromes are uncertain because these patients were excluded from pivotal trials. METHODS: In a multicenter trial, non-ST elevation acute coronary syndromes patients with prior coronary artery bypass graft were prospectively screened in 4 acute hospitals. Medically stabilized patients were randomized to invasive management (invasive group) or noninvasive management (medical group). The primary outcome was adherence with the randomized strategy by 30 days. A blinded, independent Clinical Event Committee adjudicated predefined composite outcomes for efficacy (all-cause mortality, rehospitalization for refractory ischemia/angina, myocardial infarction, hospitalization because of heart failure) and safety (major bleeding, stroke, procedure-related myocardial infarction, and worsening renal function). RESULTS: Two hundred seventeen patients were screened and 60 (mean±SD age, 71±9 years, 72% male) were randomized (invasive group, n=31; medical group, n=29). One-third (n=10) of the participants in the invasive group initially received percutaneous coronary intervention. In the medical group, 1 participant crossed over to invasive management on day 30 but percutaneous coronary intervention was not performed. During 2-years' follow-up (median [interquartile range], 744 [570-853] days), the composite outcome for efficacy occurred in 13 (42%) subjects in the invasive group and 13 (45%) subjects in the medical group. The composite safety outcome occurred in 8 (26%) subjects in the invasive group and 9 (31%) subjects in the medical group. An efficacy or safety outcome occurred in 17 (55%) subjects in the invasive group and 16 (55%) subjects in the medical group. Health status (EuroQol 5 Dimensions) and angina class in each group were similar at 12 months. CONCLUSIONS: More than half of the population experienced a serious adverse event. An initial noninvasive management strategy is feasible. A substantive health outcomes trial of invasive versus noninvasive management in non-ST elevation acute coronary syndromes patients with prior coronary artery bypass grafts appears warranted. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01895751.

"Real World" Eligibility for Sacubitril/Valsartan in Unselected Heart Failure Patients: Data from the Swedish Heart Failure Registry.

PURPOSE: PARADIGM-HF demonstrated the superiority of sacubitril/valsartan over enalapril in patients with heart failure and reduced ejection fraction (HF-REF). How widely applicable sacubitril/valsartan treatment is in unselected patients with HF-REF is not known. We examined eligibility of patients with HF-REF for treatment with sacubitril/valsartan, according to the criteria used in PARADIGM-HF, in the Swedish Heart Failure Registry (SwedeHF). METHODS: Patients were considered potentially eligible if they were not hospitalized, had symptoms (NYHA class II-IV) and a reduced LVEF (≤ 40%), and were prescribed an angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) at a dose equivalent to enalapril ≥ 10 mg daily. In these patients, we evaluated further eligibility according to the main additional PARADIGM-HF inclusion criteria. RESULTS: Of 12,866 outpatients in NYHA functional class II-IV with an LVEF ≤ 40%, 9577 were prescribed at least 10 mg of enalapril (or equivalent) daily. Complete additional data were available for 3099 of these patients (32.4%) and of them 75.5% were potentially eligible for treatment with sacubitril/valsartan. The most common reason for ineligibility was a low natriuretic peptide level (n = 462, 14.9%). Only a small proportion of patients were ineligible due to low eGFR or serum potassium level. Because only 78% of patients were taking ≥ 10 mg enalapril or equivalent daily, only 58.9% of all patients (75.5% of 78%) were eligible for sacubitril/valsartan. CONCLUSIONS: Between 34 and 76% of symptomatic patients with HF-REF in a 'real world' population are eligible for treatment with sacubitril/valsartan, depending on background ACEI/ARB dose. The most common reason for ineligibility is a low natriuretic peptide level.

Interplay of autophagy, receptor tyrosine kinase signalling and endocytic trafficking.

Vesicular trafficking events play key roles in the compartmentalization and proper sorting of cellular components. These events have crucial roles in sensing external signals, regulating protein activities and stimulating cell growth or death decisions. Although mutations in vesicle trafficking players are not direct drivers of cellular transformation, their activities are important in facilitating oncogenic pathways. One such pathway is the sensing of external stimuli and signalling through receptor tyrosine kinases (RTKs). The regulation of RTK activity by the endocytic pathway has been extensively studied. Compelling recent studies have begun to highlight the association between autophagy and RTK signalling. The influence of this interplay on cellular status and its relevance in disease settings will be discussed here.

Non-invasive versus invasive management in patients with prior coronary artery bypass surgery with a non-ST segment elevation acute coronary syndrome: study design of the pilot randomised controlled trial and registry (CABG-ACS).

INTRODUCTION: There is an evidence gap about how to best treat patients with prior coronary artery bypass grafts (CABGs) presenting with non-ST segment elevation acute coronary syndromes (NSTE-ACS) because historically, these patients were excluded from pivotal randomised trials. We aim to undertake a pilot trial of routine non-invasive management versus routine invasive management in patients with NSTE-ACS with prior CABG and optimal medical therapy during routine clinical care. Our trial is a proof-of-concept study for feasibility, safety, potential efficacy and health economic modelling. We hypothesise that a routine invasive approach in patients with NSTE-ACS with prior CABG is not superior to a non-invasive approach with optimal medical therapy. METHODS AND ANALYSIS: 60 patients will be enrolled in a randomised clinical trial in 4 hospitals. A screening log will be prospectively completed. Patients not randomised due to lack of eligibility criteria and/or patient or physician preference and who give consent will be included in a registry. We will gather information about screening, enrolment, eligibility, randomisation, patient characteristics and adverse events (including post-discharge). The primary efficacy outcome is the composite of all-cause mortality, rehospitalisation for refractory ischaemia/angina, myocardial infarction and hospitalisation for heart failure. The primary safety outcome is the composite of bleeding, stroke, procedure-related myocardial infarction and worsening renal function. Health status will be assessed using EuroQol 5 Dimensions (EQ-5D) assessed at baseline and 6 monthly intervals, for at least 18 months. TRIAL REGISTRATION NUMBER: NCT01895751 (ClinicalTrials.gov).

Comparing LCZ696 with enalapril according to baseline risk using the MAGGIC and EMPHASIS-HF risk scores: an analysis of mortality and morbidity in PARADIGM-HF.

BACKGROUND: Although most patients in the PARADIGM-HF (Prospective Comparison of ARNI With ACEI to Determine Impact on Global Mortality and Morbidity in Heart Failure) trial had mild symptoms, there is a poor correlation between reported functional limitation and prognosis in heart failure. OBJECTIVES: The aim of this study was to examine the spectrum of risk in PARADIGM-HF and the effect of LCZ696 across that spectrum. METHODS: This study analyzed rates of the primary composite outcome of cardiovascular death or heart failure hospitalization, its components, and all-cause mortality using the MAGGIC (Meta-Analysis Global Group in Chronic Heart Failure) and EMPHASIS-HF (Eplerenone in Mild Patients Hospitalization and Survival Study in Heart Failure) risk scores to categorize patients. The authors determined whether risk, on the basis of these scores, modified the treatment effect of LCZ696. RESULTS: The complete MAGGIC risk score was available for 8,375 of the 8,399 patients in PARADIGM-HF. The median MAGGIC score was 20 (IQR: 16 to 24). An increase of 1 point was associated with a 6% increased risk for the primary endpoint (p < 0.001) and a 7% increased risk for cardiovascular death (p < 0.001). The benefit of LCZ696 over enalapril for the primary endpoint was similar across the spectrum of risk (p = 0.159). Treating 100 patients for 2 years with LCZ696 instead of enalapril led to 7 fewer patients in the highest quintile of risk experiencing primary outcomes, compared with 3 in the lowest quintile. Analyses using the EMPHASIS-HF risk score gave similar findings. CONCLUSIONS: Although most PARADIGM-HF patients had mild symptoms, many were at high risk for adverse outcomes and obtained a large absolute benefit from LCZ696, compared with enalapril, over a relatively short treatment period. LCZ696's benefit was consistent across the spectrum of risk. (PARADIGM-HF trial [Prospective Comparison of ARNI With ACEI to Determine Impact on Global Mortality and Morbidity in Heart Failure]; NCT01035255).

A lethal cocktail: gastric perforation following liquid nitrogen ingestion.

We report a case of gastric perforation in an 18-year-old girl as a result of ingesting an alcoholic drink containing liquid nitrogen. The drink was purchased in licensed premises. The extent of the injury necessitated total gastrectomy with Roux-en Y reconstruction. We review the literature, discuss the mechanism of injury and consider the implications for medical services. The authors believe this case is of educational interest to professionals working in emergency medicine, general surgery and public health fields. It raises awareness of a rare injury, but one that may be more commonly encountered because of developing social trends. It informs surgeons confronted with this type of injury that trauma to the gastrointestinal tract can be extensive and preoperative contact with oesophago-gastric colleagues is advisable. Public health bodies must be aware of, and monitor, the use of liquid nitrogen in this way and consider regulation to prevent further injuries.

Squamous cell carcinoma arising in discoid lupus erythematosus lesions of the ears infected with human papillomavirus.

We describe a 51-year-old white man with discoid lupus erythematosus (DLE) of the head, neck, trunk, and upper extremities of more than 20 years' duration who developed rapidly progressive squamous cell carcinoma (SCC) of the bilateral ear helices. Human papillomavirus (HPV) was detected from excised specimens from the ears via tissue immunohistochemistry. Human papillomavirus infection of discoid lesions may be responsible for the rapid progression of SCC of this patient's bilateral ear helices.