Luc Camoin - Academia.edu (original) (raw)

Papers by Luc Camoin

The Cushing's syndrome results from chronic exposure to excess glucocorticoids produced by th... more The Cushing's syndrome results from chronic exposure to excess glucocorticoids produced by the adrenal cortex. The most common feature of patients with Cushing's syndrome is central obesity associated with dyslipidaemia and insulin resistance leading to type 2 diabetes and cardiovascular diseases. In the adipocytes, triacylglycerol and choles- terol esters are stored within an intracellular lipid droplet covered by a monolayer of phospholipids and surrounded by proteins involved in the regulation of lipolysis. Since the protein composition of adipocyte lipid droplets from patients with Cushing's syndrome has not yet been reported, we used two-dimensional gel electrophoresis followed by mass spectrometry to identify the main lipid droplet-associated proteins from peri-adrenal adipose cell of patients with this syndrome. The lipid droplet proteome of peri-adrenal adipose cell of patients with Cushing's syndrome is highly complex and contains more than 500 proteins. MAL...

Contamination of the environment after the Chernobyl and Fukushima Daiichi nuclear power plant (N... more Contamination of the environment after the Chernobyl and Fukushima Daiichi nuclear power plant (NPP) disasters led to the exposure of a large number of humans and wild animals to radioactive substances. However, the sub-lethal consequences induced by these absorbed radiological doses remain understudied and the long-term biological impacts largely unknown. We assessed the biological effects of chronic exposure to ionizing radiation (IR) on embryonic development by exposing zebrafish embryo from fertilization and up to 120 hours post-fertilization (hpf) at dose rates of 0.5 mGy/h, 5 mGy/h and 50 mGy/h, thereby encompassing the field of low dose rates defined at 6 mGy/h. Chronic exposure to IR altered larval behaviour in a light-dark locomotor test and affected cardiac activity at a dose rate as low as 0.5 mGy/h. The multi-omics analysis of transcriptome, proteome and transcription factor binding sites in the promoters of the deregulated genes, collectively points towards perturbation...

Nef is a human immunodeficiency virus type 1 (HIV-1) auxiliary protein that plays an important ro... more Nef is a human immunodeficiency virus type 1 (HIV-1) auxiliary protein that plays an important role in virus replication and the onset of acquired immunodeficiency. Although known functions of Nef might explain its contribution to HIV-1-associated pathogenesis, how Nef increases virus infectivity is still an open question. In vitro, Nef-deleted viruses have a defect that prevents efficient completion of early steps of replication. We have previously shown that this restriction is not due to the absence of Nef in viral particles. Rather, a loss of function in virus-producing cells accounts for the lower infectivity of nef-deleted viruses compared to wild-type (WT) viruses. Here we used DiGE and iTRAQ to identify differences between the proteomes of WT and nef-deleted viruses. We observe that glucosidase II is enriched in WT virions, whereas Ezrin, ALG-2, CD81, and EHD4 are enriched in nef-deleted virions. Functional analysis shows that glucosidase II, ALG-2, and CD81 have no or only ...

P36 is one of the immunodominant sperm antigens identified by antibodies eluted from the spermato... more P36 is one of the immunodominant sperm antigens identified by antibodies eluted from the spermatozoa of infertile men. In a previous study, we isolated and characterized this auto‐antigen as a glycoprotein with several isoforms. Specific rabbit antibodies were produced to investigate sperm topography and the role of P36 in the fertilization process and we showed that P36 is present on the equatorial segment of acrosome‐reacted spermatozoa and is involved in sperm‐binding and the penetration of zona‐free hamster oocytes. In the present study, we demonstrated, by means of immunofluorescence and electron microscopy, that P36 is present all over the acrosomal membranes of non‐reacted spermatozoa. We also investigated the role of P36 in the acrosome reaction and sperm binding to the zona pellucida (ZP). The exposure of capacitated spermatozoa to rabbit anti‐P36 antibodies had no effect on primary fixation to the ZP, but inhibited secondary binding to the ZP and the Ca2+ ionophore‐induced...

BackgroundThe epigenetic machinery is frequently altered in acute myeloid leukemia. Focusing on c... more BackgroundThe epigenetic machinery is frequently altered in acute myeloid leukemia. Focusing on cytogenetically normal (CN) AML, we previously described an abnormal H3K27me3 enrichment covering 70 kb on the HIST1 cluster (6.p22) in CN-AML patient blasts. Here, we further investigate the molecular, functional, and prognosis significance of this epigenetic alteration named H3K27me3 HIST1 in NPM1-mutated (NPM1mut) CN-AML.ResultsWe found that three quarter of the NPM1mut CN-AML patients were H3K27me3 HIST1high. H3K27me3 HIST1high group of patients was associated with a favorable outcome independently of known molecular risk factors. In gene expression profiling, the H3K27me3 HIST1high mark was associated with lower expression of the histone genes HIST1H1D, HIST1H2BG, HIST1H2AE, and HIST1H3F and an upregulation of genes involved in myelomonocytic differentiation. Mass spectrometry analyses confirmed that the linker histone protein H1d, but not the other histone H1 subtypes, was downregul...

Upregulation of the developmental Wnt/planar cell polarity pathway is observed in many cancers an... more Upregulation of the developmental Wnt/planar cell polarity pathway is observed in many cancers and is associated with cancer development at early and late stages. We recently showed that PRICKLE1 and VANGL2, two core Wnt/PCP components, are overexpressed in triple negative breast cancer and associated with poor prognosis. PRICKLE1 is a cytoplasmic protein phosphorylated by the poorly described serine/threonine kinase MINK1 which triggers its localization at the plasma membrane, a key step for its function. Knockdown experiments have demonstrated that MINK1 and PRICKLE1 contribute to TNBC cell motility and spreading in vitro and in vivo. However, the identity of MINK1 substrates and the role of MINK1 enzymatic activity in this process have not yet been addressed issues. We carried out a phosphoproteomic strategy and identified novel MINK1 substrates including LL5β. LL5β is a membrane scaffold molecule that anchors microtubules at the cell cortex through its association with the plus-...

Oncogene

Among the more than 160 PDZ containing proteins described in humans, the cytoplasmic scaffold Scr... more Among the more than 160 PDZ containing proteins described in humans, the cytoplasmic scaffold Scribble stands out because of its essential role in many steps of cancer development and dissemination. Its fame has somehow blurred the importance of homologous proteins, Erbin and Lano, all belonging to the LRR and PDZ (LAP) protein family first described twenty years ago. In this review, we will retrace the history of LAP family protein research and draw attention to their contribution in cancer by detailing the features of its members at the structural and functional levels, and highlighting their shared-but also different-implication in the tumoral process.

Invasion/metastasis axis is the major driver of cancer mortality. By maintaining tissue cohesion,... more Invasion/metastasis axis is the major driver of cancer mortality. By maintaining tissue cohesion, E-cadherin is considered as a protective marker for tumoral progression. However, recent studies suggested that the appearance of hybrid epithelial-mesenchymal (E/M) cells still expressing E-cadherin is favourable for the establishment of metastasis. This hypothesis is consistent with the observation that most pancreatic ductal adenocarcinomas (PDAC) are invasive and express E-cadherin in primary tumour and metastases. By using a data constituted by a series of patient-derived xenografts (PDX) from the PaCaOmics multi-centric clinical trial, we show that E-cadherin expression is not associated with stages of the pathology, prognosis, and overall survival in PDAC. The role of E-cadherin in PDAC aggressiveness was tested both in vitro and in cancer cell implantation models. We show that E-cadherin is a key component of membrane protrusions implicated in the extracellular matrix remodellin...

Proceedings of the National Academy of Sciences

Exosomes, extracellular vesicles (EVs) of endosomal origin, emerge as master regulators of cell-t... more Exosomes, extracellular vesicles (EVs) of endosomal origin, emerge as master regulators of cell-to-cell signaling in physiology and disease. Exosomes are highly enriched in tetraspanins (TSPNs) and syndecans (SDCs), the latter occurring mainly in proteolytically cleaved form, as membrane-spanning C-terminal fragments of the proteins. While both protein families are membrane scaffolds appreciated for their role in exosome formation, composition, and activity, we currently ignore whether these work together to control exosome biology. Here we show that TSPN6, a poorly characterized tetraspanin, acts as a negative regulator of exosome release, supporting the lysosomal degradation of SDC4 and syntenin. We demonstrate that TSPN6 tightly associates with SDC4, the SDC4-TSPN6 association dictating the association of TSPN6 with syntenin and the TSPN6-dependent lysosomal degradation of SDC4-syntenin. TSPN6 also inhibits the shedding of the SDC4 ectodomain, mimicking the effects of matrix meta...

BMC Cancer

Background: We report here a correlation analysis conducted along with a phase II trial assessing... more Background: We report here a correlation analysis conducted along with a phase II trial assessing bevacizumab in combination with weekly paclitaxel. Methods: Circulating pro/anti-angiogenic factors were assessed on day 1 (D1) and day 8 (D8). The prognostic value for progression-free survival (PFS) was evaluated using a Cox model with biomarkers as continuous variables. Results: Among the 51 patients enrolled and treated in this trial, biomarker analysis was performed for 42: 18 in Arm A (single-agent) and 24 in Arm B (combination). With a median follow-up of 46 months, PFS was 5.5 versus 5. 7 months, respectively (p = 0.75). According to univariate analysis, factors associated with a poor PFS were as follows: visceral angiosarcoma, de novo angiosarcoma, and high PlGF and low VEGF-C baseline values. In multivariate analysis, de novo angiosarcoma (HR = 2.5; p = 0.024) and baseline VEGF-C value (HR = 0.7; p = 0.003) were significant prognostic factors. We observed a significant increase in circulating PlGF (< 0.001) and a decrease in VEGF (< 0.001) during bevacizumab treatment. An increase in FGF was associated with a poor outcome. Conclusions: De novo angiosarcoma and a low baseline level of VEGF-C were found to be associated with a poor prognosis. Addition of bevacizumab induces major changes in circulating biomarkers (VEGF and PlGF) in a short timeframe without impacting PFS. Trial registration: Retrospectively registered on EudraCT N°2009-017020-59 and NCT01303497 (February 24, 2011).

PROTEOMICS

SCRIB is a scaffold protein containing leucine-rich repeats (LRR) and PSD-95/Dlg-A/ZO-1 domains (... more SCRIB is a scaffold protein containing leucine-rich repeats (LRR) and PSD-95/Dlg-A/ZO-1 domains (PDZ) that localizes at the basolateral membranes of polarized epithelial cells. Deregulation of its expression or localization leads to epithelial defects and tumorigenesis in part as a consequence of its repressive role on several signaling pathways including AKT, ERK, and HIPPO. In the present work, a proteomic approach is used to characterize the protein complexes associated to SCRIB and its paralogue LANO. Common and specific sets of proteins associated to SCRIB and LANO by MS are identified and an extensive landscape of their associated networks and the first comparative analysis of their respective interactomes are provided. Under proteasome inhibition, it is further found that SCRIB is associated to the-catenin destruction complex that is central in Wnt/-catenin signaling, a conserved pathway regulating embryonic development and cancer progression. It is shown that the SCRIB/-catenin interaction is potentiated upon Wnt3a stimulation and that SCRIB plays a repressing role on Wnt signaling. The data thus provide evidence for the importance of SCRIB in the regulation of the Wnt/-catenin pathway.

Background: Prostate cancer is a major public health issue, mainly because patients relapse after... more Background: Prostate cancer is a major public health issue, mainly because patients relapse after androgen deprivation therapy. Proteomic strategies, aiming to reflect the functional activity of cells, are nowadays among the leading approaches to tackle the challenges not only of better diagnosis, but also of unraveling mechanistic details related to disease etiology and progression. Methods: We conducted here a large SILAC-based Mass Spectrometry experiment to map the proteomes and phosphoproteomes of four widely used prostate cell lines, namely PNT1A, LNCaP, DU145 and PC3,representative of different cancerous and hormonal status. Results: We identified more than 3000 proteins and phosphosites, from which we quantified more than 1000 proteins and 500 phosphosites after stringent filtering. Extensive exploration of this proteomics and phosphoproteomics dataset allowed characterizing housekeeping as well as cell-line specific proteins, phosphosites and functional features of each cel...

British Journal of Cancer

BACKGROUND: Triple-negative breast cancers (TNBC) are poor-prognosis tumours candidate to chemoth... more BACKGROUND: Triple-negative breast cancers (TNBC) are poor-prognosis tumours candidate to chemotherapy as only systemic treatment. We previously found that PRICKLE1, a prometastatic protein involved in planar cell polarity, is upregulated in TNBC. We investigated the protein complex associated with PRICKLE1 in TNBC to identify proteins possibly involved in metastatic dissemination, which might provide new prognostic and/or therapeutic targets. METHODS: We used a proteomic approach to identify protein complexes associated with PRICKLE1. The mRNA expression levels of the corresponding genes were assessed in 8982 patients with invasive primary breast cancer. We then characterised the molecular interaction between PRICKLE1 and the guanine nucleotide exchange factor ECT2. Finally, experiments in Xenopus were carried out to determine their evolutionarily conserved interaction. RESULTS: Among the PRICKLE1 proteins network, we identified several small G-protein regulators. Combined analysis of the expression of PRICKLE1 and small G-protein regulators had a strong prognostic value in TNBC. Notably, the combined expression of ECT2 and PRICKLE1 provided a worst prognosis than PRICKLE1 expression alone in TNBC. PRICKLE1 regulated ECT2 activity and this interaction was evolutionary conserved. CONCLUSIONS: This work supports the idea that an evolutionarily conserved signalling pathway required for embryogenesis and activated in cancer may represent a suitable therapeutic target.

Clinical Proteomics

Background: Colorectal cancer (CRC) remains a major cause of cancer fatalities in developed count... more Background: Colorectal cancer (CRC) remains a major cause of cancer fatalities in developed countries. The risk of death is correlated to the stage of CRC during the primary diagnosis. Early diagnosis is closely associated with enhanced survival rate. We therefore investigated the AP-F13A1 as a potential protein marker of CRC. Methods: The protein expression of FXIII in 40 serum samples was evaluated by enzyme-linked immunosorbent assays. Additionally, targeted proteomic assays (LC-PRM) were used to evaluate the expression of the activation peptide of F13A1 (AP-F13A1) in a further 113 serum samples. Results were analyzed by the Wilcoxon test and receiver operating characteristic curves generated to assess statistical differences and diagnostic factors between CRC patients and controls. Results: AP-F13A1 was quantified in human serum samples using calibration curves with excellent linearity. AP-F13A1 was reduced in CRC patients using PRM assays from two distinct biobanks. The AUC for AP-F13A1 were 0.95 and 0.93. Sensitivity/specificity values for the two sets of patients were 75%/95% and 71%/95% respectively. Conclusion: We have presented the proof of principle that in vivo release of AP-F13A1 can be measured by PRMbased strategies in CRC serum samples. AP-F13A1 may be an effective serological biomarker as part of a screening program of CRC detection.

$Research paper thumbnail of O-GlcNAcylation site mapping by (azide-alkyne) click chemistry and mass spectrometry following intensive fractionation of skeletal muscle cells proteins$

Journal of proteomics, Jan 30, 2018

The O-linked-N-acetyl-d-glucosaminylation (O-GlcNAcylation) modulates numerous aspects of cellula... more The O-linked-N-acetyl-d-glucosaminylation (O-GlcNAcylation) modulates numerous aspects of cellular processes. Akin to phosphorylation, O-GlcNAcylation is highly dynamic, reversible, and responds rapidly to extracellular demand. Despite the absolute necessity to determine post-translational sites to fully understand the role of O-GlcNAcylation, it remains a high challenge for the major reason that unmodified proteins are in excess comparing to the O-GlcNAcylated ones. Based on a click chemistry approach, O-GlcNAcylated proteins were labelled with azido-GalNAc and coupled to agarose beads. The proteome extracted from C2C12 myotubes was submitted to an intensive fractionation prior to azide-alkyne click chemistry. This combination of fractionation and click chemistry is a powerful methodology to map O-GlcNAc sites; indeed, 342 proteins were identified through the identification of 620 peptides containing one or more O-GlcNAc sites. We localized O-GlcNAc sites on proteins involved in si...

Oncotarget

Introduction: treatments targeting the Human Epidermal Growth Factor Receptor 2 (HER2/ERBB2) have... more Introduction: treatments targeting the Human Epidermal Growth Factor Receptor 2 (HER2/ERBB2) have improved the natural history of HER2-positive breast cancer. However, except HER2 protein expression and gene amplification, there is no predictive biomarker to guide the HER2-targeted therapies. We developed Parallel reaction monitoring (PRM) a powerful approach, to quantify and evaluate key proteins involved in the HER2 pathway and/or anti-HER2 treatment sensitivity. Results: in BCLs, PRM measurements correlated with western blot immunocytochemistry and transcriptomic data. At baseline, higher expression of HER2, EGFR, PTEN and HER3 but lower expression of phospho-HER2 correlated with trastuzumab sensitivity. Under trastuzumab, PRM demonstrated a decrease in HER2 and an increase in phospho-HER2, which correlated with drug sensitivity. The opposite was observed under lapatinib. HER2 quantification was also correlated with immunohistochemistry in PDXs and clinical breast cancer samples. Discussion: in conclusion, PRM-based assay, developed to quantify proteins of the HER2 pathway in breast cancer samples revealed a large magnitude of expression, which may have relevance in terms of treatment sensitivity. Materials and Methods: we first evaluated PRM in term of sensitivity, linearity and reproducibility. PRM was then applied to breast cancer cell lines (BCLs) including BCLs exposed to anti-HER2 agents, patient-derived xenografts (PDXs) and frozen breast cancer samples.

Journal of molecular biology, Jan 4, 2018

With the high number of patients infected by tuberculosis (TB) and the sharp increase of drug res... more With the high number of patients infected by tuberculosis (TB) and the sharp increase of drug resistant TB cases, developing new drugs to fight this disease has become increasingly urgent. In this context, analogs of the naturally occurring enolphosphates Cyclipostins and Cyclophostin (CyC analogs) offer new therapeutic opportunities. The CyC analogs display potent activity both in vitro and in infected macrophages against several pathogenic mycobacteria including Mycobacterium tuberculosis and Mycobacterium abscessus. Interestingly, these CyC inhibitors target several enzymes with active site serine or cysteine residues that play key roles in mycobacterial lipid and cell wall metabolism. Among them, TesA, a putative thioesterase involved in the synthesis of phthiocerol dimycocerosates (PDIMs) and phenolic glycolipids (PGLs), has been identified. These two lipids (PDIM and PGL) are non-covalently bound to the outer cell wall in several human pathogenic mycobacteria and are important...

Bioorganic chemistry, Jan 29, 2018

A set of 19 oxadiazolone (OX) derivatives have been investigated for their antimycobacterial acti... more A set of 19 oxadiazolone (OX) derivatives have been investigated for their antimycobacterial activity against two pathogenic slow-growing mycobacteria, Mycobacterium marinum and Mycobacterium bovis BCG, and the avirulent Mycobacterium tuberculosis (M. tb) mc6230. The encouraging minimal inhibitory concentrations (MIC) values obtained prompted us to test them against virulent M. tb H37Rv growth either in broth medium or inside macrophages. The OX compounds displayed a diversity of action and were found to act either on extracellular M. tb growth only with moderated MIC, or both intracellularly on infected macrophages as well as extracellularly on bacterial growth. Of interest, all OX derivatives exhibited very low toxicity towards host macrophages. Among the six potential OXs identified, HPOX, a selective inhibitor of extracellular M. tb growth, was selected and further used in a competitive labelling/enrichment assay against the activity-based probe Desthiobiotin-FP, in order to ide...

The Journal of biological chemistry, Feb 4, 2018

An increasing prevalence of cases of drug-resistant tuberculosis requires the development of more... more An increasing prevalence of cases of drug-resistant tuberculosis requires the development of more efficacious chemotherapies. We previously reported the discovery of a new class of Cyclipostins and Cyclophostin (CyC) analogs exhibiting potent activity against Mycobacterium tuberculosis both in vitro and in infected macrophages. Competitive labeling/enrichment assays combined with MS have identified several serine or cysteine enzymes in lipid and cell wall metabolism as putative targets of these CyC compounds. These targets included members of the antigen 85 (Ag85) complex (i.e. Ag85A, Ag85B, and Ag85C), responsible for biosynthesis of trehalose dimycolate (TDM) and mycolylation of arabinogalactan. Herein, we used biochemical and structural approaches to validate the Ag85 complex as a pharmacological target of the CyC analogs. We found that CyC7β, CyC8β, and CyC17 bind covalently to the catalytic Ser124 residue in Ag85C, inhibit mycolyltransferase activity, i.e. the transfer of a fat...

La Revue de Médecine Interne