Biology subjects

Raymond, A.-A.

Publications and source records attributed to Raymond, A.-A..

8 recordsLinked to original sources

bioRxiv2026

Standardized brain and plasma EV enrichment pipeline validated for Single sample multi-Omic and fatty acids applications in Mouse and Human

Extracellular vesicles (EVs) are key mediators of intercellular communication, yet their molecular profiles across tissues and species remain poorly characterized, particularly due to currently available methods requiring a large amount of biological material (tissue or biofluids). Here, we established a workflow allowing the deep phenotyping of EV cargos starting from single samples of human and mouse origin. We took advantage of standardised EV isolation procedures and multi-omic techniques for the isolation and analysis of EVs from brain and plasma of human and mouse, integrating flow cytometric profiling, proteomics, miRNA sequencing, and fatty acid profiling. Here we report specific brain-derived EVs proteome, enriched in neuronal and glial proteins, polyunsaturated fatty acids profiles, and distinct miRNAs. At the periphery, we also report plasma-derived EVs signatures reflecting immune, metabolic, and systemic transport functions. Despite these expected material-specific differences, EVs from the same source displayed greater similarity across species than EVs from different material, supporting the translational relevance of mouse models. Importantly, using state-of-the-art miRNA profiling approach, we identified novel EV-specific miRNAs in human and mouse brain EVs, potentially allowing the exploration of new roles in neuronal signalling. Overall, we report here a method enabling deep multi-omic characterization from minimal starting material, offering a practical approach for studies with limited biological samples. These findings also demonstrate that the origin strongly shapes EV composition, highlighting conserved and species-specific molecular features, and provide a scalable framework for multi-omic investigations of EV biology. Summary StatementWe present a standardised workflow allowing multi-omic profiling of brain and plasma-derived EVs from minimal human and mouse material. Our findings reveal both tissue-specific and species specific EV molecular signatures.

neuroscience↗

bioRxiv2025

p190A/ARHGAP35 and p190B/ARHGAP5 proteins in endometrial cancer, a novel cancer-relevant paralog interplay

Endometrial cancer is one of the main gynecological malignancies worldwide, with an estimated 320, 000 new cases annually. Several studies highlight ARHGAP35 as a significantly mutated gene in these tumors. It encodes for the protein p190RhoGAP-A (p190A), which is a major regulator of the small GTPase family of proteins. ARHGAP5 is a paralog of ARHGAP35 that encodes the protein p190RhoGAP-B (p190B). By analyzing human endometrial cancer samples, we found a co-occurrence of mutations in ARHGAP35 and ARHGAP5 genes and we reported that both are less expressed at the mRNA level in tumoral samples compared to healthy tissues. We were interested in understanding the impact of p190A/B under-expression in endometrial cancer and the relationship between the two paralogs. To do so, we have used CRISPR/Cas9 technology to generate HEC-1-A knockout cells for p190A and p190B. We showed that removal of each paralog led to a similar actin remodeling phenotype with the formation of Cross-Linked Actin Networks (CLANs), dependent on the Rho/ROCK pathway. Moreover, proteomic analysis of p190A and p190B knockout cells highlighted similar affected cell functions. Finally, our study demonstrates a synthetic lethality between p190A and p190B where removal of both paralogs is deleterious in endometrial cancer cells, unveiling a potential actionable vulnerability.

cancer biology↗

bioRxiv2025

Proteomic profiling of advanced hepatocellular carcinoma identifies predictive signatures of response to treatments

PurposeHepatocellular carcinoma (HCC) is the most common form of liver cancer with a bad prognosis in case of advanced HCC, only eligible for palliative systemic therapies. After a decade of exclusive sorafenib monotherapy, with a response rate of <10%, the advent of immunotherapies represents a revolution in HCC. The combination of atezolizumab/bevacizumab is recommended as the first-line systemic treatment, with a response rate around 30%. However, there are currently no predictive factors for response to these treatment options. Experimental DesignWe profiled, by high-resolution mass spectrometry-based proteomics combined with machine learning analysis, a selected cohort of fixed biopsies of advanced HCC. We grouped subjects according to their objective response to treatments, corresponded to a tumor regression vs tumor progression at 4 months after treatment. ResultsWe generated a proteome database of 50 selected HCC samples. We compared the relative protein abundance between tumoral and non-tumoral liver tissues from advanced HCC patients treated. The clear distinction of these two groups for each treatment is based on deregulation for 141 protein or 87 for atezolizumab/bevacizumab and sorafenib treatment, respectively. These specific proteomic signatures were sufficient to predict the response to treatment, and revealed biological pathways involved in treatments resistance. Particularly, we validated a shift in tumor cell metabolism with an immunosuppressive environment involved in the resistance to atezolizumab/bevacizumab combination. ConclusionsWe performed an in-depth analysis of quantitative proteomic data from HCC biopsies to predict the treatment response to advanced HCC giving the ability to optimize patient management.

cancer biology↗

bioRxiv2024

Src promotes tumor cell invasion by hijacking the translation machinery

The Src oncogene controls cancer cell invasiveness by promoting invadosome formation and extracellular matrix degradation (ECM). Invadosomes are enriched in the eukaryotic translation initiation factor 3 (eIF3) complex associated with a local mRNA translation activity mandatory for their maintenance. Here, we show that Src regulates mRNA translation by controlling the expression of eIF3 subunits. Among them, eIF3h/e/d are essential for invadosome formation and ECM degradation. We demonstrate that Src controls the canonical mTOR/eIF4E and the non-canonical eIF3d cap-dependent translation initiation pathways. We show that both pathways are necessary for invadosome formation and their ECM degradation function. Finally, we highlighted a correlation between Src and eIF3h/e/d overexpression, which is associated with poor prognosis in hepatocellular carcinoma (HCC) patients and controls the ECM degradation and invasive properties of HCC cells. These findings identify Src as a major regulator of translation initiation pathways, which leads to invadosome formation, ECM degradation and tumor cell invasion. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=152 SRC="FIGDIR/small/606119v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@1804203org.highwire.dtl.DTLVardef@16ddae8org.highwire.dtl.DTLVardef@13ecca5org.highwire.dtl.DTLVardef@1ed685a_HPS_FORMAT_FIGEXP M_FIG Graphical abstract C_FIG

cell biology↗

bioRxiv2023

Repression of exosome secretion by mutated β-catenin contributes to immune escape in hepatocellular carcinoma

Immune checkpoint inhibitors have produced encouraging results in cancer patients. However, the majority of {beta}-catenin-mutated tumors have been described as lacking immune infiltrates and resistant to immunotherapy. The mechanisms by which oncogenic {beta}-catenin affects immune surveillance remain unclear. Herein, we highlighted the involvement of {beta}-catenin in the regulation of the exosomal pathway and, by extension, in immune/cancer cell communication in hepatocellular carcinoma (HCC). We showed that mutated {beta}-catenin represses expression of SDC4 and RAB27A, two main actors in exosome biogenesis, in both liver cancer cell lines and HCC patient samples. Using nanoparticle tracking analysis and live-cell imaging, we further demonstrated that activated {beta}-catenin represses exosome release. Then, we demonstrated in 3D spheroid models that activation of {beta}-catenin promotes a decrease in immune cell infiltration through a defect in exosome secretion. Taken together, our results provide the first evidence that oncogenic {beta}-catenin plays a key role in exosome biogenesis. Our study gives new insight into the impact of {beta}-catenin mutations on tumor microenvironment remodeling, which could lead to the development of new strategies to enhance immunotherapeutic response.

cancer biology↗

bioRxiv2023

Loss of RND3/RHOE controls entosis through LAMP1 expression in hepatocellular carcinoma

Entosis is a process that leads to the formation of cell-in-cell structures commonly found in cancers. Here, we identified entosis in hepatocellular carcinoma and the loss of Rnd3 as an efficient inducer of this mechanism. We characterized the different stages and the molecular regulators of entosis induced after Rnd3 silencing. We demonstrated that this process depends on RhoA/ROCK pathway, but not on E-cadherin. The proteomic profiling of entotic cells allowed us to identify LAMP1 as a protein upregulated by Rnd3 silencing and implicated not only in the degradation final stage of entosis, but also in the full mechanism. Moreover, we found a positive correlation between the presence of entotic cells and the metastatic potential of tumors in human patient samples. Altogether, these data suggest the involvement of entosis in liver tumor progression and highlight a new perspective for entosis analysis in medicine research as a novel therapeutic target.

cancer biology↗

bioRxiv2022

The E3 ubiquitin ligase FBXL6 controls the quality of newly synthesized mitochondrial ribosomal proteins

The large majority of mitochondrial proteins is synthesized in the cytosol and then imported to the organelle. To ensure proper mitochondrial functions, the quality of these proteins needs to be guaranteed. Here, we show that the E3 ubiquitin ligase F-box/LRR-repeat protein 6 (FBXL6) participates to the quality of these mitochondrial proteins at the level of the cytosolic translation. We found that lack of FBXL6 has severe effects including mitochondrial ribosomal protein aggregations, altered mitochondrial metabolism and inhibited cell cycle progression in oxidative conditions. FBXL6 was found to interact specifically with ribosomal-associated quality control proteins and chaperones involved in the regulation of newly synthesized proteins and also it preferentially binds newly synthesized mitochondrial ribosomal proteins. Consistently, deletion of the RQC protein, NEMF or HSP70-family chaperone HSPA1A impedes FBXL6 interaction with its substrate. In addition, cells lacking FBXL6 display altered degradation of defective mitochondrial ribosomal protein containing C-terminal alanyl-threonyl extension.

cell biology↗

bioRxiv2019

Counteracting resistance to targeted therapy in melanoma by inhibiting discoidin domain receptors

Anti-BRAF plus anti-MEK are used as first-line treatment of patients with metastatic melanomas harboring BRAF V600E mutation. The main issue with targeted therapy is acquired cellular resistance. In 70% of acquired resistance, melanoma cells switch their phenotype and become more aggressive and invasive. The molecular signature of this phenotype is MITF low, AXL high associated with actin cytoskeleton reorganization. After this switch, resistant cells present an anarchic cell proliferation due to MAP kinase pathway hyper-activation. We demonstrate that resistant cell lines presenting phenotype switching overexpress DDR1 and DDR2. We show that DDR2 inhibition induces a decrease in AXL and reduces actin stress fiber formation. Once this phenotype switching is acquired, we report that both DDRs promotes tumor cell proliferation, but only DDR2 can over-activate the MAP kinase pathway in resistant invasive cells in vitro and in vivo. Therefore, DDRs inhibition could be a promising strategy for countering this resistance mechanism. SignificanceOur results show that DDR2 is a relevant target in melanoma resistance. DDR2 is required at the beginning of resistance for melanoma cell phenotype switching to occur. After phenotype switching, DDRs promote tumor cell proliferation of resistant invasive melanoma cells, but only DDR2 is able to over-activate the MAP kinase pathway. We put forward dasatinib (a DDR inhibitor) as a potential second-line treatment after targeted dual therapy for resistant patients overexpressing DDRs.

cancer biology↗