Biology subjects

Jean, C.

Publications and source records attributed to Jean, C..

7 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↗

bioRxiv2024

Inducible FAK Deletion but not FAK Inhibition in Endothelial Cells Activates p53 to Suppress Tumor Growth in PYK2-null Mice

Focal adhesion kinase (FAK) functions as a signaling and scaffolding protein within endothelial cells (ECs) impacting blood vessel function and tumor growth. Interpretations of EC FAK-null phenotypes are complicated by related PYK2 (protein tyrosine kinase 2) expression, and to test this, we created PYK2-/- FAKfl/fl mice with tamoxifen-inducible EC-specific Cre recombinase expression. At 11 weeks of age, EC FAK inactivation resulted in increased heart and lung mass and vascular leakage only on a PYK2-/- background. Surprisingly, [~]90% of PYK2-/- EC FAK-/- mice survived to 75 weeks of age. Syngeneic melanoma, breast, or lung carcinoma tumors did not grow in PYK2-/- EC FAK-/- mice, but tumors grew normally in PYK2-/- EC FAKfl/fl mice lacking Cre. This tumor inhibitory phenotype was associated with abortive EC vessel sprouting, enhanced EC p53 tumor suppressor and p21CIP1 (cyclin-dependent inhibitor 1) expression, and alterations in serum cytokine levels. To discern the role of FAK kinase versus scaffolding activity in ECs, we generated kinase defective (FAK K454R, KD) PYK2-/- EC FAKfl/KD and PYK2-/- EC FAKfl/WT (WT, wildtype) mice. Hemizygous EC FAK-/KD expression supported primary tumor growth but not metastasis, implicating EC FAK activity in tumor dissemination. In vitro, hemizygous expression of either WT or KD FAK suppressed EC p21CIP1 levels and cell death observed in primary PYK2-/- EC FAK-/- ECs. Combined FAK and PYK2 knockdown in tumor cells also increased p21CIP1 and PARP1 (poly ADP-ribose polymerase 1) levels in a p53-associated manner impacting anchorage-independent growth. Together, these results underscore the linkage between PYK2 and FAK loss with p53 activation impacting tumor growth. Impact StatementPYK2-null combined with endothelial cell-specific FAK transgenic mouse models show that loss of FAK activity limits tumor spread and that genetic or chemical degradation preventing combined FAK-PYK2 expression may be an approach to induce a p53-associated anti-tumor response.

cell biology↗

bioRxiv2024

Exploiting facial side similarities to improve AI-driven sea turtle photo-identification systems

AO_SCPLOWBSTRACTC_SCPLOWAnimal Photo-identification (photo-ID) denotes the process of identifying individual animals based on their unique and stable morphological characteristics. It has been proven to be a particularly useful tool for a variety of studies on sea turtles increasing the knowledge of their ecology and informing conservation efforts. The photo-ID process in sea turtles is predominantly based on the geometric patterns of the scales of their two head sides which are unique to every individual, and also different from side to side. As such, both manual and automated photo-ID techniques are performed under a side-specific image retrieval setting. There, a query image showing a single profile of an unknown individual, either left or right, is only compared to images of previously identified individuals showing the same side. Here, by employing the recently introduced state-of-the-art deep feature extractor MegaDescriptor, we show for the first time an inherit deep visual similarity between left and right facial profiles of the same individuals in three sea turtle species. We show that the similarity between the left and right profiles of the same individual with respect to geometry, coloration and pigmentation, is on average higher than the similarity between profiles of different individuals. The similarity is detectable even when images are taken years apart and under diverse settings and conditions. We perform several image retrieval experiments under scenarios which mimic realistic sea turtle photo-ID matching processes, where we also allow comparisons of opposite sides in the matching process which have no spatial overlap. We show that the detection and exploitation of this similarity is translated to improved accuracies when compared to the traditional side-specific image retrieval setting. Notably this similarity cannot be detected and thus neither explored by the so-far state-of-the-art sea turtle photo-ID automated methods such as those based on SIFT. Our work leads to a change of paradigm for the sea turtle photo-ID workflows which will be further facilitated by the constant improvement of deep feature-based re-identification methods and paves the path for adopting similar workflows in other animal species as well.

ecology↗

bioRxiv2020

Translatome-based classification reveals a dual metabolic dependency of a new tumor subtype of pancreatic cancer.

Molecular profiling of Pancreatic Ductal Adenocarcinoma (PDA), based on transcriptomic analyses, identifies two main prognostic subtypes (basal-like and classical), but does not allow personalized first-line treatment. To date, tumors have not been profiled based on protein synthesis rates, yet the step of mRNA translation is highly deregulated in both PDA cancer cells and their microenvironment. Using a collection of twenty-seven pancreatic Patient-Derived Xenografts (PDX), we performed genome-wide analysis of translated mRNA (translatome). Unsupervised bioinformatics analysis revealed a new tumor subtype harboring a low protein synthesis rate, but associated with a robust translation of mRNAs encoding effectors of the integrated stress response (ISR), including the transcription factor ATF4. Functional characterization of the "ISR-activated" human cancer cells revealed a high resistance to drugs, low autophagic capacities, and importantly, metabolic impairments in the serine synthesis and transsulfuration pathways. Overall, our study highlights the strength of translatomic profiling on PDA, which here revealed an unforeseen drug-resistant cancer cell phenotype, whose auxotrophy to both serine and cysteine may be amenable to targeted therapy.

cancer biology↗

bioRxiv2019

Reprogrammed Pteropus Bat Stem Cells Present Distinct Immune Signature And Are Highly Permissive For Henipaviruses

Bats are unique among mammals due to the ability of powered flight and exceptional longevity. They are also asymptomatic hosts for numerous viruses, including recently emerged zoonotic Henipaviruses Nipah and Hendra, which are highly pathogenic for humans and other mammals. Better understanding of how bats control viral infection requires development of relevant permissive cellular experimental models. By applying a somatic reprogramming protocol to Pteropus bat primary cells, using a novel combination of ESRRB, CDX2, and c-MYC transcription factors, we generated bat reprogrammed cells exhibiting stem cell-like characteristics and a neural stem cell-like molecular signature. These cells present a unique interferon-stimulated transcriptomic signature and both produce and respond to interferon type-I, highlighting differences between stem cells from bats and other mammals. In contrast to primary bat cells, these reprogrammed cells are highly susceptible to infection by Henipavirus, thereby enabling isolation of new bat viruses, study of virus-bat interactions, and better understanding of bat biology. Summary sentenceSomatic reprogramming provides new bat stem cells with unique immune properties and original viral permissivness

cell biology↗

bioRxiv2019

FAK activity sustains intrinsic and acquired ovarian cancer resistance to platinum chemotherapy

Gene copy number changes, cancer stem cell (CSC) increases, and platinum chemotherapy resistance contribute to poor prognosis in patients with recurrent high grade serous ovarian cancer (HGSOC). CSC phenotypes involving Wnt-{beta}-catenin and aldehyde dehydrogenase activities, platinum resistance, and tumor initiating frequency are here associated with spontaneous genetic gains, including genes encoding KRAS, MYC and FAK, in a new murine model of ovarian cancer (KMF). Noncanonical FAK signaling was sufficient to sustain human and KMF tumorsphere proliferation, CSC survival, and platinum resistance. Increased FAK tyrosine phosphorylation occurred in HGSOC patient tumors surviving neo-adjuvant platinum and paclitaxel chemotherapy and platinum resistant tumorspheres acquired FAK dependence for growth. Importantly, combining a pharmacologic FAK inhibitor with platinum overcame chemoresistance and triggered apoptosis in vitro and in vivo. Knockout, rescue, genomic and transcriptomic analyses collectively identified more than 400 genes regulated along a FAK/{beta}-catenin/Myc axis impacting stemness and DNA repair in HGSOC, with 66 genes gained in a majority of Cancer Genome Atlas samples. Together, these results support combinatorial testing of FAK inhibitors for the treatment of recurrent ovarian cancer.\n\nGraphical Summary\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=125 SRC=\"FIGDIR/small/594184_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (52K):\norg.highwire.dtl.DTLVardef@20c737org.highwire.dtl.DTLVardef@1f714faorg.highwire.dtl.DTLVardef@823560org.highwire.dtl.DTLVardef@7e6219_HPS_FORMAT_FIGEXP M_FIG C_FIG Key PointsO_LIHigh grade serous ovarian carcinoma tumors contain PTK2 (FAK) 8q24.3 gains associated with prognostic differences.\nC_LIO_LIKMF, a new murine ovarian cancer model with K-Ras, Myc, and FAK gene gains and intrinsic platinum resistance.\nC_LIO_LIFAK activation in tumors surviving platinum chemotherapy promotes cancer stem cell survival.\nC_LIO_LIFAK facilitates a {beta}-catenin-Myc signaling axis controlling gene expression supporting platinum resistance.\nC_LIO_LIFAK activity is essential for KMF tumor growth and is a targetable cellular adaptation of platinum resistance.\nC_LI

cancer biology↗

bioRxiv2018

Three-dimensional culture of chicken primordial germ cells in chemically defined media containing the functional polymer FP003

Scalable production of avian suspension cell exhibits a valuable potential on therapeutic application by producing recombinant protein and as the substrate for virus growth. This study sought to establish a system with chemically defined components for three-dimensional (3D) culture of chicken primordial germ cells (cPGCs), a pluripotent avian cell type. cPGCs were cultured in medium supplemented with the functional polymer FP003. Viscoelasticity was low in this medium, and cPGCs did not sediment,and consequently their expansion was improved. The total number of cPGCs increased by 17-fold after 1week of culture in 3D-FAot medium, an aseric chemically defined medium containing FP003, indicating that this medium enhances the expansion of cPGCs. Moreover, cPGC cell lines stably expressed the germline-specific reporter VASA:tdTOMATO, as well as other markers of cPGCs, for more than 1 month upon culture in 3D-FAot medium, indicating that the characteristics of these cells are maintained. cPGCs harboring both PGK:EGFP and VASA:tdTOMATO robustly expressed both fluorescent proteins upon culture in 3D-FAot, suggesting that this approach is perspective for recombinant protein production. In summary,this novel 3D culture system can be used to efficiently expand cPGCs in suspension without mechanical stirring or loss of cellular properties. This system provides a platform for large-scale culture ofcPGCs in industry.

cell biology↗