Biology subjects

Dupuy, J.

Publications and source records attributed to Dupuy, J..

4 recordsLinked to original sources

bioRxiv2026

LRP-1 promotes tumor progression of triple negative breast cancers by coordinating extracellular matrix remodeling and immune cell infiltration

Structural AbstractO_ST_ABSBackgroundC_ST_ABSTriple-negative breast cancer (TNBC) represents a major clinical challenge due to its aggressiveness, heterogeneity and limited availability of effective targeted therapy. We investigated whether LRP-1, a multifunctional cell-surface endocytic and signaling receptor, contributes to TNBC progression. MethodsUsing CRISPR-Cas9, LRP-1-deficient murine 4T1 and human HS578-T TNBC cells were used. Functional consequences were assessed through migration, invasion, and 3D spheroid assays, imaging of focal adhesions and actin organization, atomic force microscopy, and plasmin activity assays. Global molecular reprogramming was analyzed by label-free quantitative proteomics and secretomics. LRP-1-deficient or proficient 4T1 cells were implanted orthotopically in immunocompetent mice; tumor progression was monitored longitudinally while peritumoral collagen architecture and immune microenvironment composition were characterized by second harmonic generation imaging and immunohistochemistry. ResultsWe show that LRP-1 loss reduces TNBC aggressiveness, as reflected by decreased migration and invasive capacity, reduced spheroid evasion, and significant morphological changes in focal adhesion and actin structure. LRP-1-deficient cells became stiffer and showed lower LOXL-4 levels, while pericellular proteolytic activity remained unchanged, suggesting other proteases mechanism. Multi-omic analysis revealed alterations in extracellular matrix (ECM), epithelial-mesenchymal transition, and inflammatory pathways. In vivo, LRP-1-deficiency reduced tumor progression and peritumoral collagen deposition, while increasing CD8+ T and Natural Killer cell infiltration, together with a cytokine profiling compatible with a more immune-permissive microenvironment. ConclusionsLRP-1 act as a key contributor in TNBC progression through matrix remodeling, mechano-adaptation, and immune exclusion. Positioning it as a candidate biomarker for TNBC patients who are likely to benefit from stroma-targeting therapies. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/732906v2_ufig1.gif" ALT="Figure 1"> View larger version (60K): org.highwire.dtl.DTLVardef@1b595c2org.highwire.dtl.DTLVardef@7b208aorg.highwire.dtl.DTLVardef@1956e54org.highwire.dtl.DTLVardef@17e55d0_HPS_FORMAT_FIGEXP M_FIG C_FIG

Cancer Biology↗

bioRxiv2023

X-Ray Structure and enzymatic study of a Bacterial NADPHoxidase highlight the activation mechanism of eukaryoticNOX

NADPH oxidases (NOX) are transmembrane proteins that professionally produce reactive oxygen species (ROS) and are distributed widely in both eukaryotes and prokaryotes. Eukaryotes use the ROS products for innate immune defense and signaling; the seven human isoforms of NOX participate in critical physiological and pathophysiological processes. Recently solved structures of two human NOX isoforms provide much new information, but do not fully elucidate controls on the electron transfer pathway from NAD(P)H substrate through FAD and heme cofactors to the final ROS product. SpNOX, a bacterial NOX homolog from Streptococcus pneumoniae, shows robust constitutive activity in detergent solution, making it a good prototype for exploring electron transfer in the NOX family. Here we present crystal structures of wildtype and mutant full-length and dehydrogenase (DH) domain-only constructs of SpNOX. The isolated DH domain acts as a flavin reductase, and both DH and full-length constructs use either NADPH or NADH as substrate. Our data supports hydride transfer from NAD(P)H to FAD as the rate limiting step in electron transfer. Using the DH domain, we demonstrate the role of F397 in allowing access of nicotinamide to the flavin isoalloxazine, while in the full-length construct, we used mutants and flavin analogs to confirm the contribution of both domains to flavin binding observed in the structure. Comparison with homologous enzymes suggests distal heme access may influence the final electron acceptor, while the relative position of DH and TM does not necessarily correlate with activity of a given NOX family member. Based on this comparison, SpNOX appears to be a good model of active NOX2, which allows us to propose an explanation for NOX2s requirement for activation.

biochemistry↗

bioRxiv2023

Reduction, removal or replacement of sodium nitrite in a model of cured and cooked meat: a joint evaluation of consequences on microbiological issues in food safety, colon ecosystem and colorectal carcinogenesis

ScopeEpidemiological and experimental evidence reported that processed meat consumption is associated with colorectal cancer (CRC) risk. Several studies suggest the involvement of nitrite or nitrate additives via N-nitroso-compound formation (NOCs). Methods and resultsCompared to the reference level (120 mg/kg of ham), the effects of sodium nitrite reduction (90 mg/kg of ham), removal and replacement were analysed on ham characteristics and in a CRC rat model. Sodium nitrite removal and reduction induced a similar decrease in CRC preneoplastic lesions, but only reduction led to (i) an inhibitory effect on Listeria monocytogenes growth comparable to that obtained using the reference nitrite level of 120 mg/kg and (ii) an effective control of lipid peroxidation. Among the three alternatives tested, none led to a significant gain when compared to the 120 mg/kg ham reference level: vegetable stock, due to nitrate presence, was very similar to this reference nitrite level, yeast extract induced a strong luminal peroxidation and no decrease in preneoplastic lesions despite the absence of NOCs, and polyphenol rich extract induced the clearest downward trend on preneoplastic lesions but the concomitant presence of nitrosyl iron in feces. Except vegetable stock, other alternatives were less efficient than sodium nitrite ([≥] 90 mg/kg) in reducing L. monocytogenes growth. ConclusionNitrite reduction (90mg/kg) effectively reduced CRC risk through limiting NOC formation and lipid peroxidation, while mitigating L. monocytogenes risks from cooked hams. Going further in reduction should be possible if accompanied by antioxidants to limit lipid peroxidation and appropriate use-by dates.

pathology↗

bioRxiv2022

Curcumin and NCLX Inhibitors Share Anti-Tumoral Mechanisms in Microsatellite-Instability-Driven Colorectal Cancer

Colorectal cancer (CRC) is associated with high mortality worldwide and new targets are needed to overcome treatment resistance. Recent evidences highlight a role of the mitochondria calcium homeostasis in the development of CRC. In this context, we aimed to evaluate the role of the mitochondrial sodium-calcium-lithium exchanger (NCLX) and its targeting in CRC. We also identified curcumin as a new potential inhibitor of NCLX. In vitro, curcumin exerted strong anti-tumoral activity through its action on NCLX with mtCa2+ and reactive oxygen species overload associated with a mitochondrial membrane depolarization, leading to reduced ATP production and apoptosis through mitochondrial permeability transition pore opening concomitant with G2/M cell cycle arrest. NCLX inhibition with either CGP37157 (a benzodiazepine derivative), small interfering RNA-mediated knock-down or knockout approaches reproduced the effects of curcumin. Altered mitochondrial respiration, cellular aerobic glycolysis and endoplasmic reticulum-mitochondria membrane perturbations participated in these mechanisms. In a xenograft mouse model, NCLX inhibitors decreased CRC tumor growth. Both transcriptomic analysis of The Cancer Genome Atlas dataset and immunohistochemical analysis of tissue microarrays from 381 patients with microsatellite instability (MSI)-driven CRC demonstrated that higher NCLX expression was associated with MSI status and for the first time NCLX expression was significantly associated with recurrence-free survival in MSI CRC patients. Our findings provide strong evidence that blocking NCLX inhibits CRC in vitro and in vivo. We highlight a novel anti-tumoral mechanism of curcumin through its action on NCLX and mitochondria calcium overload that could benefit for therapeutic treatment of patients with MSI CRC.

cancer biology↗