Metabolic adaptation towards glycolysis supports resistance to neoadjuvant chemotherapy in early triple negative breast cancers.

BACKGROUND: Neoadjuvant chemotherapy (NAC) is the standard of care for patients with early-stage triple negative breast cancers (TNBC). However, more than half of TNBC patients do not achieve a pathological complete response (pCR) after NAC, and residual cancer burden (RCB) is associated with dismal long-term prognosis. Understanding the mechanisms underlying differential treatment outcomes is therefore critical to limit RCB and improve NAC efficiency. METHODS: Human TNBC cell lines and patient-derived organoids were used in combination with real-time metabolic assays to evaluate the effect of NAC (paclitaxel and epirubicin) on tumor cell metabolism, in particular glycolysis. Diagnostic biopsies (pre-NAC) from patients with early TNBC were analyzed by bulk RNA-sequencing to evaluate the predictive value of a glycolysis-related gene signature. RESULTS: Paclitaxel induced a consistent metabolic switch to glycolysis, correlated with a reduced mitochondrial oxidative metabolism, in TNBC cells. In pre-NAC diagnostic biopsies from TNBC patients, glycolysis was found to be upregulated in non-responders. Furthermore, glycolysis inhibition greatly improved response to NAC in TNBC organoid models. CONCLUSIONS: Our study pinpoints a metabolic adaptation to glycolysis as a mechanism driving resistance to NAC in TNBC. Our data pave the way for the use of glycolysis-related genes as predictive biomarkers for NAC response, as well as the development of inhibitors to overcome this glycolysis-driven resistance to NAC in human TNBC patients.

Therapeutic potential of extracellular vesicles derived from cardiac progenitor cells in rodent models of chemotherapy-induced cardiomyopathy.

Background: Current treatments of chemotherapy-induced cardiomyopathy (CCM) are of limited efficacy. We assessed whether repeated intravenous injections of human extracellular vesicles from cardiac progenitor cells (EV-CPC) could represent a new therapeutic option and whether EV manufacturing according to a Good Manufacturing Practices (GMP)-compatible process did not impair their bioactivity. Methods: Immuno-competent mice received intra-peritoneal injections (IP) of doxorubicin (DOX) (4 mg/kg each; cumulative dose: 12 mg/kg) and were then intravenously (IV) injected three times with EV-CPC (total dose: 30 billion). Cardiac function was assessed 9-11 weeks later by cardiac magnetic resonance imaging (CMR) using strain as the primary end point. Then, immuno-competent rats received 5 IP injections of DOX (3 mg/kg each; cumulative dose 15 mg/kg) followed by 3 equal IV injections of GMP-EV (total dose: 100 billion). Cardiac function was assessed by two dimensional-echocardiography. Results: In the chronic mouse model of CCM, DOX + placebo-injected hearts incurred a significant decline in basal (global, epi- and endocardial) circumferential strain compared with sham DOX-untreated mice (p = 0.043, p = 0.042, p = 0.048 respectively) while EV-CPC preserved these indices. Global longitudinal strain followed a similar pattern. In the rat model, IV injections of GMP-EV also preserved left ventricular end-systolic and end-diastolic volumes compared with untreated controls. Conclusions: Intravenously-injected extracellular vesicles derived from CPC have cardio-protective effects which may make them an attractive user-friendly option for the treatment of CCM.

Biomaterial-embedded extracellular vesicles improve recovery of the dysfunctional myocardium.

Extracellular vesicles (EV) are increasingly recognized as a therapeutic option in heart failure. They are usually administered by direct intramyocardial injections with the caveat of a rapid wash-out from the myocardium which might weaken their therapeutic efficacy. To improve their delivery in the failing myocardium, we designed a system consisting of loading EV into a clinical-grade hyaluronic acid (HA) biomaterial. EV were isolated from umbilical cord-derived mesenchymal stromal cells. The suitability of HA as a delivery platform was then assessed in vitro. Rheology studies demonstrated the viscoelastic and shear thinning behaviors of the selected HA allowing its easy injection. Moreover, the release of HA-embedded EV was sustained over more than 10 days, and EV bioactivity was not altered by the biomaterial. In a rat model of myocardial ischemia reperfusion, we showed that HA-embedded EV preserved cardiac function (echocardiography), improved angiogenesis and decreased both apoptosis and fibrosis (histology and transcriptomics) when compared to intramyocardial administration of EV alone. These data thus strengthen the concept that inclusion of EV into a clinically useable biomaterial might optimize their beneficial effects on post-ischemic cardiac repair.

Extracellular vesicles fail to trigger the generation of new cardiomyocytes in chronically infarcted hearts.

Background: Extracellular vesicles (EV) mediate the therapeutic effects of stem cells but it is unclear whether this involves cardiac regeneration mediated by endogenous cardiomyocyte proliferation. Methods: Bi-transgenic MerCreMer/ZEG (n = 15/group) and Mosaic Analysis With Double Markers (MADM; n = 6/group) mouse models underwent permanent coronary artery ligation and received, 3 weeks later, 10 billion EV (from human iPS-derived cardiovascular progenitor cells [CPC]), or saline, injected percutaneously under echo guidance in the peri-infarcted myocardium. Endogenous cardiomyocyte proliferation was tracked by EdU labeling and biphoton microscopy. Other end points, including cardiac function (echocardiography and MRI), histology and transcriptomics were blindly assessed 4-6 weeks after injections. Results: There was no proliferation of cardiomyocytes in either transgenic mouse strains. Nevertheless, EV improved cardiac function in both models. In MerCreMer/ZEG mice, LVEF increased by 18.3 ± 0.2% between baseline and the end-study time point in EV-treated hearts which contrasted with a decrease by 2.3 ± 0.2% in the PBS group; MADM mice featured a similar pattern as intra-myocardial administration of EV improved LVEF by 13.3 ± 0.16% from baseline whereas it decreased by 14.4 ± 0.16% in the control PBS-injected group. This functional improvement was confirmed by MRI and associated with a reduction in infarct size, the decreased expression of several pro-fibrotic genes and an overexpression of the anti-fibrotic miRNA 133-a1 compared to controls. Experiments with an anti-miR133-a demonstrated that the cardio-reparative effects of EV were partly abrogated. Conclusions: EV-CPC do not trigger cardiomyocyte proliferation but still improve cardiac function by other mechanisms which may include the regulation of fibrosis.

Rbm24 displays dynamic functions required for myogenic differentiation during muscle regeneration.

Skeletal muscle has a remarkable capacity of regeneration after injury, but the regulatory network underlying this repair process remains elusive. RNA-binding proteins play key roles in the post-transcriptional regulation of gene expression and the maintenance of tissue homeostasis and plasticity. Rbm24 regulates myogenic differentiation during early development, but its implication in adult muscle is poorly understood. Here we show that it exerts multiple functions in muscle regeneration. Consistent with its dynamic subcellular localization during embryonic muscle development, Rbm24 also displays cytoplasm to nucleus translocation during C2C12 myoblast differentiation. In adult mice, Rbm24 mRNA is enriched in slow-twitch muscles along with myogenin mRNA. The protein displays nuclear localization in both slow and fast myofibers. Upon injury, Rbm24 is rapidly upregulated in regenerating myofibers and accumulates in the myonucleus of nascent myofibers. Through satellite cell transplantation, we demonstrate that Rbm24 functions sequentially to regulate myogenic differentiation and muscle regeneration. It is required for myogenin expression at early stages of muscle injury and for muscle-specific pre-mRNA alternative splicing at late stages of regeneration. These results identify Rbm24 as a multifaceted regulator of myoblast differentiation. They provide insights into the molecular pathway orchestrating the expression of myogenic factors and muscle functional proteins during regeneration.

Extracellular vesicles from human cardiovascular progenitors trigger a reparative immune response in infarcted hearts.

AIMS: The cardioprotective effects of human induced pluripotent stem cell-derived cardiovascular progenitor cells (CPC) are largely mediated by the paracrine release of extracellular vesicles (EV). We aimed to assess the immunological behaviour of EV-CPC, which is a prerequisite for their clinical translation. METHODS AND RESULTS: Flow cytometry demonstrated that EV-CPC expressed very low levels of immune relevant molecules including HLA Class I, CD80, CD274 (PD-L1), and CD275 (ICOS-L); and moderate levels of ligands of the natural killer (NK) cell activating receptor, NKG2D. In mixed lymphocyte reactions, EV-CPC neither induced nor modulated adaptive allogeneic T cell immune responses. They also failed to induce NK cell degranulation, even at high concentrations. These in vitro effects were confirmed in vivo as repeated injections of EV-CPC did not stimulate production of immunoglobulins or affect the interferon (IFN)-γ responses from primed splenocytes. In a mouse model of chronic heart failure, intra-myocardial injections of EV-CPC, 3 weeks after myocardial infarction, decreased both the number of cardiac pro-inflammatory Ly6Chigh monocytes and circulating levels of pro-inflammatory cytokines (IL-1α, TNF-α, and IFN-γ). In a model of acute infarction, direct cardiac injection of EV-CPC 2 days after infarction reduced pro-inflammatory macrophages, Ly6Chigh monocytes, and neutrophils in heart tissue as compared to controls. EV-CPC also reduced levels of pro-inflammatory cytokines IL-1α, IL-2, and IL-6, and increased levels of the anti-inflammatory cytokine IL-10. These effects on human macrophages and monocytes were reproduced in vitro; EV-CPC reduced the number of pro-inflammatory monocytes and M1 macrophages, while increasing the number of anti-inflammatory M2 macrophages. CONCLUSIONS: EV-CPC do not trigger an immune response either in in vitro human allogeneic models or in immunocompetent animal models. The capacity for orienting the response of monocyte/macrophages towards resolution of inflammation strengthens the clinical attractiveness of EV-CPC as an acellular therapy for cardiac repair.

Clinical Translation of Pluripotent Stem Cell Therapies: Challenges and Considerations.

Although the clinical outcomes of cell therapy trials have not met initial expectations, emerging evidence suggests that injury-mediated tissue damage might benefit from the delivery of cells or their secreted products. Pluripotent stem cells (PSCs) are promising cell sources primarily because of their capacity to generate stage- and lineage-specific differentiated derivatives. However, they carry inherent challenges for safe and efficacious clinical translation. This Review describes completed or ongoing trials of PSCs, discusses their potential mechanisms of action, and considers how to address the challenges required for them to become a major therapy, using heart repair as a case study.

[Pluripotent stem cells for the treatment of heart failure: current status, persisting issues and perspectives]. / Les cellules souches pluripotentes dans le traitement de l'insuffisance cardiaque - Statut actuel, problèmes et perspectives.

Although the first wave of cell therapy trials has not commonly yielded clinically meaningful improvements, some encouraging hints have emerged which suggest that stem cells or their secreted products could ultimately find a place within the armamentarium of therapies that can be offered to patients with heart failure. In this setting, pluripotent stem cells raise a particular interest because of their unique ability to generate lineage-specific cells which can be transplanted at the desired stage of differentiation. This review discusses the current status of research in this field, the persisting roadblocks that need to be overcome and the approaches which might hasten the clinical applications of this cell type.

TITLE: Les cellules souches pluripotentes dans le traitement de l'insuffisance cardiaque - Statut actuel, problèmes et perspectives. ABSTRACT: Bien que les premiers essais de thérapie cellulaire dans l'insuffisance cardiaque se soient soldés pour la plupart par une absence d'améliorations cliniquement pertinentes, des signaux encourageants ont commencé à émerger, signaux qui suggèrent que les cellules souches, ou leurs produits de sécrétion, pourraient finalement trouver leur place dans l'arsenal des traitements proposables aux patients atteints d'insuffisance cardiaque. Dans ce cadre, les cellules souches pluripotentes suscitent un intérêt particulier en raison de leur capacité unique à donner naissance à des cellules spécifiques d'un lignage donné et transplantables au stade de différenciation souhaité. Cette revue discute l'état actuel de la recherche dans ce domaine, les problèmes qui restent à résoudre et les approches susceptibles d'accélérer les applications cliniques de ce type cellulaire.