Biology subjects

Sabatier, M.

Publications and source records attributed to Sabatier, M..

6 recordsLinked to original sources

bioRxiv2026

A mouse model of metastasis-induced breast cancer cachexia with non-cachectic controls bearing isogenic primary tumors

Background Patients with advanced cancer frequently develop cachexia, an involuntary weight-loss condition that correlates strongly with metastatic burden. Despite this clinical association, metastasis is rarely considered in preclinical research of cancer cachexia, which is in part due to the lack of rigorously established animal models to investigate metastasis-associated cancer cachexia. Methods To establish an animal model of metastasis-associated cancer cachexia, here we focused on syngeneic mouse models of breast cancer. Using the metastatic 4T1 murine breast cancer cell line and its isogenic non-metastatic 67NR cell line, we generated primary tumors via orthotopic injection into the mammary fat pad and surgically resected the primary tumor to allow sufficient time for spontaneous metastatic outgrowth, or generated experimental lung metastases by direct intravenous injection into the tail vein. Across these tumor-bearing groups, we systematically characterized the metastatic burden and cachectic phenotypes of the mice, including body weight, food intake, body composition, muscle mass, grip strength, locomotor activity, energy expenditure, and respiratory exchange ratio. To isolate the contribution of reduced food intake to the cachectic phenotypes, we pair-fed orthotopic 4T1 tumor-bearing mice (which were non-cachectic) to mice with 4T1 lung metastases (which were cachectic). We further measured muscle atrophy gene expression and profiled circulating cytokines and metabolic hormones for the mouse groups. Results Body weight loss occurred exclusively in mice bearing lung metastases from 4T1 tumors, with no weight loss observed in mice bearing either primary 4T1 tumors or 67NR lung tumors, thus presenting a model of cancer cachexia that is driven by 4T1 lung metastasis. Comprehensive cachexia characterization demonstrated that the 4T1 metastasis model recapitulates all key features of cachexia, manifesting as reduced food intake (or anorexia), depletion of adipose tissues, loss of lean mass including muscle mass loss, and reduced grip strength. Pair-feeding non-cachectic primary 4T1 tumor-bearing mice to 4T1 metastatic mice led to the same losses in body weight, fat, and lean mass as in cachectic mice, but no change in grip strength, indicating that anorexia is the primary driver of tissue wasting whereas muscle weakness arises through a food intake-independent mechanism. Moreover, we identified distinct circulating cytokines and metabolic hormones associated with the metastasis-driven cachexia. Conclusions Our results establish a metastasis-induced breast cancer cachexia model with a tightly matched control group, providing a platform for the field to identify metastasis-derived cachectic mediators and pathways.

cancer biology↗

bioRxiv2025

Plasma plasmalogen levels and risk of lymph node positive breast cancer

Lymph node involvement is a key predictor of poor breast cancer prognosis. Systemic lipid alterations can contribute to cancer cell survival in lymph nodes, but their relevance in humans remains unclear. Here, we combine human epidemiologic analyses from the Nurses Health Study 2 and complementary mechanistic studies in mouse models to investigate how systemic lipid profiles relate to lymph node positive breast cancer. We show that in pre-diagnostic human plasma (n=511), lower levels of phosphatidylethanolamine (PE) and phosphatidylcholine (PC)-enriched plasmalogens are associated with increased risk of lymph node positivity, with stronger associations in samples collected closer to diagnosis. Consistent with the human data, lower levels of PE and PC-enriched plasma plasmalogens are found in mice with nodal involvement. Furthermore, in mice, dietary PUFA depletion reduces lipid oxidation in breast cancer cells in lymph nodes and promotes their survival and metastatic spread. These findings suggest that reduced levels of PE and PC-plasmalogens and decreased PUFA availability creates a lipid environment that enables breast cancer lymph node involvement.

cancer biology↗

bioRxiv2022

C/EBPα confers dependence to fatty acid anabolic pathways and vulnerability to lipid oxidative stress in FLT3-mutant leukemia

While transcription factor C/AAT-enhancer binding protein (C/EBP) is critical for normal and leukemic differentiation, its role on cell and metabolic homeostasis is largely unknown in cancer. Here, multi-omics analyses uncovered a coordinated activation of C/EBP and Fms-like tyrosine kinase 3 (FLT3) that increased lipid anabolism in vivo and in patients with FLT3-mutant acute myeloid leukemia (AML). Mechanistically, C/EBP regulated FASN-SCD axis to promote fatty acid (FA) biosynthesis and desaturation. We further demonstrated that FLT3 or C/EBP inactivation decreased mono-unsaturated FAs incorporation to membrane phospholipids through SCD downregulation. Consequently, SCD inhibition enhanced susceptibility to lipid redox stress. Moreover, this C/EBP-dependent adaptation of FA homeostasis was exploited by combining FLT3 and glutathione peroxidase 4 (GPX4) inhibition to trigger lipid oxidative stress, enhancing ferroptotic death of FLT3-mutant AML cells. Altogether, our study reveals a C/EBP function in lipid homeostasis and adaptation to redox stress, and a previously unreported vulnerability of FLT3-mutant AML with promising therapeutic application. SIGNIFICANCEThe transcription factor C/EBP is as a master regulator of normal and leukemic myeloid differentiation. Here, we discovered that C/EBP regulates fatty acid biosynthesis and metabolic adaptation to redox imbalance in leukemic cells. This confers a vulnerability to lipid oxidative stress to FLT3-mutant cells and supports novel therapeutic opportunities for patients.

cancer biology↗

bioRxiv2020

Adrenomedullin-CALCRL Axis Controls Relapse-Initiating Drug Tolerant Acute Myeloid Leukemia Cells

Drug tolerant leukemic cell subpopulations may explain frequent relapses in acute myeloid leukemia (AML), suggesting that these Relapse-Initiating Cells (RICs) persistent after chemotherapy represent bona fide targets to prevent drug resistance and relapse. We uncovered that the G-protein coupled receptor CALCRL is expressed in leukemic stem cells (LSCs) and RICs, and that the overexpression of CALCRL and/or of its ligand adrenomedullin (ADM) and not CGRP correlates to adverse outcome in AML. CALCRL knockdown impairs leukemic growth, decreases LSC frequency and sensitizes to cytarabine in patient-derived xenograft (PDX) models. Mechanistically, the ADM-CALCRL axis drives cell cycle, DNA repair and mitochondrial OxPHOS function of AML blasts dependent on E2F1 and BCL2. Finally, CALCRL depletion reduces LSC frequency of RICs post-chemotherapy in vivo. In summary, our data highlight a critical role of ADM-CALCRL in post-chemotherapy persistence of these cells, and disclose a promising therapeutic target to prevent relapse in AML.

cancer biology↗

bioRxiv2020

Mitochondrial determinants of response and resistance to venetoclax plus cytarabine duplet therapy in acute myeloid leukemia

The development of resistance to conventional and targeted therapy represents a major clinical barrier in treatment of acute myeloid leukemia (AML). We show that the resistance to cytarabine (AraC) and its associated mitochondrial phenotype were reversed by genetic silencing or pharmacological inhibition of BCL2 in a caspase-dependent manner. BCL2-inhibitor venetoclax (VEN) enhancement of AraC efficacy was independent of differentiation phenotype, a characteristic of response to another combination of VEN with hypomethylating agents (HMA). Furthermore, transcriptional profiles of patients with low response to VEN+AraC mirrored those of low responders to VEN+HMA in clinical trials. OxPHOS was found to be a patient stratification marker predictive of effective response to VEN+AraC but not to VEN+AZA. Importantly, whereas three cell subpopulations specifically emerged in VEN+AraC residual disease and were characterized by distinct developmental and transcriptional programs largely driven by MITF, E2F4 and p53 regulons, they each encoded proteins involved in assembly of NADH dehydrogenase complex. Notably, treatment of VEN+AraC-persisting AML cells with an ETCI inhibitor significantly increased the time-to-relapse in vivo. These findings provide the scientific rationale for new clinical trials of VEN+AraC combinations, especially in patients relapsing or non-responsive to chemotherapy, or after failure of frontline VEN+HMA regimen.

cancer biology↗

bioRxiv2020

Evaluation of NGS-based approaches for SARS-CoV-2 whole genome characterisation

Since the beginning of the COVID-19 outbreak, SARS-CoV-2 whole-genome sequencing (WGS) has been performed at unprecedented rate worldwide with the use of very diverse Next Generation Sequencing (NGS) methods. Herein, we compare the performance of four NGS-based approaches for SARS-CoV-2 WGS. Twenty four clinical respiratory samples with a large scale of Ct values (from 10.7 to 33.9) were sequenced with four methods. Three used Illumina sequencing: an in-house metagenomic NGS (mNGS) protocol and two newly commercialized kits including a hybridization capture method developed by Illumina (DNA Prep with Enrichment kit and Respiratory Virus Oligo Panel, RVOP) and an amplicon sequencing method developed by Paragon Genomics (CleanPlex SARS-CoV-2 kit). We also evaluated the widely used amplicon sequencing protocol developed by ARTIC Network and combined with Oxford Nanopore Technologies (ONT) sequencing. All four methods yielded near-complete genomes (>99%) for high viral loads samples, with mNGS and RVOP producing the most complete genomes. For mid viral loads, 2/8 and 1/8 genomes were incomplete (<99%) with mNGS and both CleanPlex and RVOP, respectively. For low viral loads (Ct [≥]25), amplicon-based enrichment methods were the most sensitive techniques yielding complete genomes for 7/8 samples. All methods were highly concordant in terms of identity in complete consensus sequence. Just one mismatch in two samples was observed in CleanPlex vs the other methods, due to the dedicated bioinformatics pipeline setting a high threshold to call SNP compared to reference sequence. Importantly, all methods correctly identified a newly observed 34-nt deletion in ORF6 but required specific bioinformatic validation for RVOP. Finally, as a major warning for targeted techniques, a default of coverage in any given region of the genome should alert to a potential rearrangement or a SNP in primer annealing or probe-hybridizing regions and would require regular updates of the technique according to SARS-CoV-2 evolution.

genomics↗