Role of myoferlin in mitochondrial dynamics and metabolic fitness of Pancreatic Ductal Adenocarcinoma

Pancreatic cancer is the 7th most common cause of cancer mortality in the world. It is predicted to become the 2nd leading cause of cancer-related death in 2030. In the majority of cases, due to a late diagnosis, the tumor is not resectable and already disseminated. Therefore, new specific biomarkers providing early diagnosis for pancreatic cancer are needed. In addition to the lack of specific and early biomarkers, chemotherapies (gemcitabine and folfirinox) poorly improve the overall survival of Pancreatic Ductal Adenocarcinoma (PDAC) patients. Hence, a better understanding of physiopathological processes underlying PDAC is required in order to offer more effective treatments. Myoferlin is a 230 kDa protein with multiple C2 domains known to interact, through calcium binding, with negatively charged phospholipids. This protein was first described in myoblast fusion. Interestingly, Myoferlin is also overexpressed in several cancers, including pancreatic cancer, where it plays a role in endocytosis, exocytosis, and has been located in exosomes. Recently, our team showed a fragmentation of the mitochondrial network in PDAC cells when myoferlin was depleted using siRNA. Understanding the mechanism underlying this mitochondrial disruption would be of great interest as mitochondria are major actors in cancer development, progression and resistance. Owing to the known role of myoferlin in membrane fusion, we assessed its direct involvement in the mitochondrial fusion machinery. Indeed, if myoferlin is a part of the mitochondrial fusion machinery, its silencing together with an unopposed fission would lead to mitochondrial fragmentation. First, we performed immunofluorescence to colocalize myoferlin and a mitochondrial outer membrane 65kDa protein. Colocalization studies showed no significant colocalization. We then performed immunofluorescence to stained myoferlin and the main factor of mitochondrial fusion mitofusin-1/2 (MFN1/2). Colocalization image analysis revealed a 60% colocalization between both proteins. Those results were further confirmed by PLA (Proximity Ligation Assay). Finally, to evaluate a direct protein-protein interaction, we performed a co-immunoprecipitation assay. The main isoform of myoferlin appeared to coimmunoprecipitate with MFN1/2, suggesting a direct interaction between these proteins.Role of myoferlin in mitochondrial dynamics and metabolic fitness of pancreatic cance

Do Not Sleep on Linear Models: Simple and Interpretable Techniques Outperform Deep Learning for Sleep Scoring

Over the last few years, research in automatic sleep scoring has mainly focused on developing increasingly complex deep learning architectures. However, recently these approaches achieved only marginal improvements, often at the expense of requiring more data and more expensive training procedures. Despite all these efforts and their satisfactory performance, automatic sleep staging solutions are not widely adopted in a clinical context yet. We argue that most deep learning solutions for sleep scoring are limited in their real-world applicability as they are hard to train, deploy, and reproduce. Moreover, these solutions lack interpretability and transparency, which are often key to increase adoption rates. In this work, we revisit the problem of sleep stage classification using classical machine learning. Results show that state-of-the-art performance can be achieved with a conventional machine learning pipeline consisting of preprocessing, feature extraction, and a simple machine learning model. In particular, we analyze the performance of a linear model and a non-linear (gradient boosting) model. Our approach surpasses state-of-the-art (that uses the same data) on two public datasets: Sleep-EDF SC-20 (MF1 0.810) and Sleep-EDF ST (MF1 0.795), while achieving competitive results on Sleep-EDF SC-78 (MF1 0.775) and MASS SS3 (MF1 0.817). We show that, for the sleep stage scoring task, the expressiveness of an engineered feature vector is on par with the internally learned representations of deep learning models. This observation opens the door to clinical adoption, as a representative feature vector allows to leverage both the interpretability and successful track record of traditional machine learning models.Comment: The first two authors contributed equally. Submitted to Biomedical Signal Processing and Contro

Le ciblage de la myoferline induit la mitophagie et amorce la ferroptose dans les cellules cancéreuses pancréatiques

peer reviewe

Myoferlin controls mitochondrial structure and activity in pancreatic ductal adenocarcinoma, and affects tumor aggressiveness

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related death. Therapeutic options remain very limited and are based on classical chemotherapies. Energy metabolism reprogramming appears as an emerging hallmark of cancer and is considered a therapeutic target with considerable potential. Myoferlin, a ferlin family member protein overexpressed in PDAC, is involved in plasma membrane biology and has a tumor-promoting function. In the continuity of our previous studies, we investigated the role of myoferlin in the context of energy metabolism in PDAC. We used selected PDAC tumor samples and PDAC cell lines together with small interfering RNA technology to study the role of myoferlin in energetic metabolism. In PDAC patients, we showed that myoferlin expression is negatively correlated with overall survival and with glycolytic activity evaluated by 18F-deoxyglucose positron emission tomography. We found out that myoferlin is more abundant in lipogenic pancreatic cancer cell lines and is required to maintain a branched mitochondrial structure and a high oxidative phosphorylation activity. The observed mitochondrial fission induced by myoferlin depletion led to a decrease of cell proliferation, ATP production, and autophagy induction, thus indicating an essential role of myoferlin for PDAC cell fitness. The metabolic phenotype switch generated by myoferlin silencing could open up a new perspective in the development of therapeutic strategies, especially in the context of energy metabolism

Myoferlin contributes to the metastatic phenotype of pancreatic cancer cells by enhancing their migratory capacity through the control of oxidative phosphorylation

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest malignancies with an overall survival of 5%, and is the second cause of death by cancer, mainly linked to its high metastatic aggressiveness. Accordingly, understanding the mechanisms sustaining the PDAC metastatic phenotype remains a priority. In this study, we have generated and used a murine in vivo model to select clones from the human PANC-1 PDAC cell line that exhibit a high propensity to seed and metastasized into the liver. We showed that myoferlin, a protein previously reported to be overexpressed in PDAC, is significantly involved in the migratory abilities of the selected cells. We first report that highly PANC-1 metastatic clones expressed significantly higher myoferlin level than the corresponding low metastatic ones. Using scratch wound and Boyden’s chamber assays, we show that cells expressing high myoferlin level have higher migratory potential than cells characterized by a low myoferlin abundance. Moreover, we demonstrate that myoferlin silencing leads to a migration decrease associated to a reduction of mitochondrial respiration. Since mitochondrial oxidative phosphorylation has been shown to be implicated in the tumor progression and dissemination, our data identify myoferlin as a valid potential therapeutic target in PDAC

Myoferlin targeting triggers mitophagy and primes ferroptosis in pancreatic cancer cells

Myoferlin, an emerging oncoprotein, has been associated with a low survival in several cancer types including pancreas ductal adenocarcinoma where it controls mitochondria structure and respiratory functions. Owing to the high susceptibility of KRAS-mutated cancer cells to iron-dependent cell death, ferroptosis, and to the high iron content in mitochondria, we investigated the relation existing between mitochondrial integrity and iron-dependent cell death. We discovered that myoferlin targeting with WJ460 pharmacological compound triggered mitophagy and ROS accumulation culminating with lipid peroxidation and apoptosis-independent cell death. WJ460 caused a reduction of the abundance of ferroptosis core regulators xc- cystine/glutamate transporter and GPX-4. Mitophagy inhibitor Mdivi1 and iron chelators inhibited the myoferlin-related ROS production and restored cell growth. Additionally, we reported a synergic effect between ferroptosis inducers, erastin and RSL3, and WJ460

Impact of renal function on clinical outcomes after PCI in ACS and stable CAD patients treated with ticagrelor: a prespecified analysis of the GLOBAL LEADERS randomized clinical trial

Background: Impaired renal function (IRF) is associated with increased risks of both ischemic and bleeding events. Ticagrelor has been shown to provide greater absolute reduction in ischemic risk following acute coronary syndrome (ACS) in those with versus without IRF. Methods: A pre-specified sub-analysis of the randomized GLOBAL LEADERS trial (n = 15,991) comparing the experimental strategy of 23-month ticagrelor monotherapy (after 1-month ticagrelor and aspirin dual anti-platelet therapy [DAPT]) with 12-month DAPT followed by 12-month aspirin after percutaneous coronary intervention (PCI) in ACS and stable coronary artery disease (CAD) patients stratified according to IRF (glomerular filtration rate < 60 ml/min/1.73 m2). Results: At 2 years, patients with IRF (n = 2171) had a higher rate of the primary endpoint (all-cause mortality or centrally adjudicated, new Q-wave myocardial infarction [MI](hazard ratio [HR] 1.64, 95% confidence interval [CI] 1.35–1.98, padj = 0.001), all-cause death, site-reported MI, all revascularization and BARC 3 or 5 type bleeding, compared with patients without IRF. Among patients with IRF, there were similar rates of the primary endpoint (HR 0.82, 95% CI 0.61–1.11, p = 0.192, pint = 0.680) and BARC 3 or 5 type bleeding (HR 1.10, 95% CI 0.71–1.71, p = 0.656, pint = 0.506) in the experimental versus the reference group. No significant interactions were seen between IRF and treatment effect for any of the secondary outcome variables. Among ACS patients with IRF, there were no between-group differences in the rates of the primary endpoint or BARC 3 or 5 type bleeding; however, the rates of the patient-oriented composite endpoint (POCE) of all-cause death, any stroke, MI, or revascularization (pint = 0.028) and net adverse clinical events (POCE and BARC 3 or 5 type bleeding) (pint = 0.045), were lower in the experimental versus the reference group. No treatment effects were found in stable CAD patients categorized according to presence of IRF. Conclusions: IRF negatively impacted long-term prognosis after PCI. There were no differential treatment effects found with regard to all-cause death or new Q-wave MI after PCI in patients with IRF treated with ticagrelor monotherapy. Clinical trial regis

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570