Biology subjects

Lobry, C.

Publications and source records attributed to Lobry, C..

6 recordsLinked to original sources

bioRxiv2025

Associative memory in human cancer cells

In psychology and neuroscience, associative memory refers to the capacity to learn and remember a link between two unrelated items. Although associative memory is widely believed to be restricted to animals possessing a complex nervous system, several reports have suggested that single-cell organisms can be conditioned to develop an associative memory-like behavior. Here, we report that human cancer cell lines can be conditioned to associate an extracellular matrix component and Gefitinib, a drug that reduces cell migration velocity. Collagen-I was periodically paired with Gefitinib and we observed that conditioned cells progressive decreased migration velocity on collagen-I but not on other extracellular matrix components. We identified the adenosine receptor ADORA2A as a key actor regulating the acquisition of associative memory. We also observed that the magnitude of the conditioned response oscillated over time with the same periodicity as paired stimuli presentations during conditioning. We found that mitochondria morphology oscillated with the same periodicity, suggesting that memory and energy metabolisms are linked. We propose that human cancer cells can be conditioned to integrate a link between two stimuli from their environment in a process that may allow to anticipate future stress exposition.

cell biology↗

bioRxiv2025

Targetable BIRC5 dependency in therapy-resistant TP53 mutated acute myeloid leukemia

TP53 mutations across multiple cancers, including acute myeloid leukemia (AML), are associated with poor outcomes irrespective of treatment modality. However, druggable vulnerabilities beyond canonical p53 targets remain largely unexplored. We identify BIRC5 (encodes survivin), an inhibitor of the apoptosis protein (IAP) family, as a novel vulnerability in TP53 mutant AML using an unbiased, comprehensive multiomics approach -- whole-genome CRISPR knockout screen, bulk and single-cell RNA-seq, proteomics, and high-throughput drug screen. Mechanistically, BIRC5 deletion in AML restored caspase-9 and -3/7 activity and downregulated other IAPs, implicating BIRC5 as the central post-mitochondrial regulator for blocking apoptosis. p53 stabilization suppressed BIRC5 selectively in TP53 wild-type AML, explaining BIRC5 upregulation in TP53 mutant lines and AML primary tumors (n > 700). Longitudinal single-cell RNAseq (n = 22 pairs) revealed expansion of BIRC5high stem and progenitor leukemia clones in TP53 mutant AML patients post-VenAza therapy. Survivin and IAP inhibitors emerged as top combination partners with VenAza in TP53 mutant AML cells and showed potent in vivo leukemic blast inhibition in cell line and patient-derived xenograft models along with primary tumors. Beyond AML, BIRC5 was upregulated broadly across 17 of 25 TP53 mutant cancers in the TCGA cohort, and combination with survivin inhibitors overcame chemotherapy resistance in TP53 deficient triple negative breast and colorectal cancers. These findings define BIRC5 as a critical, targetable dependency and unveil survivin/IAP inhibition as a promising therapeutic axis to overcome p53-related resistance across both hematologic and solid malignancies. Key PointsO_LIBIRC5 upregulation is a novel dependency in TP53 mutant AML that mediates therapy resistance by evasion of apoptosis. C_LIO_LICombination with Survivin/IAP inhibitors overcomes venetoclax/azacitidine resistance in TP53 mutant AML. C_LI

cancer biology↗

bioRxiv2023

CXCR4 signaling strength regulates hematopoietic multipotent progenitor fate through extrinsic and intrinsic mechanisms

How cell-extrinsic niche-related and cell-intrinsic cues drive lineage specification of hematopoietic multipotent progenitors (MPPs) in the bone marrow (BM) is partly understood. We show that CXCR4 signaling strength regulates localization and fate of MPPs. In mice phenocopying the BM myeloid skewing of patients with WHIM Syndrome (WS), a rare immunodeficiency caused by gain-of-function CXCR4 mutations, enhanced mTOR signaling and overactive Oxphos metabolism were associated with myeloid rewiring of lymphoid-primed MPPs (or MPP4). Fate decision of MPP4 was also affected by molecular changes established at the MPP1 level. Mutant MPP4 displayed altered BM localization relative to peri-arteriolar structures, suggesting that extrinsic cues contribute to their myeloid skewing. Chronic treatment with CXCR4 antagonist AMD3100 or mTOR inhibitor Rapamycin rescued lymphoid capacities of mutant MPP4, demonstrating a pivotal role for the CXCR4-mTOR axis in regulating MPP4 fate. Our study thus provides mechanistic insights into how CXCR4 signaling regulates the lymphoid potential of MPPs.

cell biology↗

bioRxiv2023

Metabolically Primed Multipotent Hematopoietic Progenitors Fuel Innate Immunity

Following infection, hematopoietic stem and progenitor cells (HSPCs) support immunity by increasing the rate of innate immune cell production but the metabolic cues that guide this process are unknown. To address this question, we developed MetaFate, a method to trace the metabolic expression state and developmental fate of single cells in vivo. Using MetaFate we identified a gene expression program of metabolic enzymes and transporters that confers differences in myeloid differentiation potential in a subset of HSPCs that express CD62L. Using single-cell metabolic profiling, we confirmed that CD62Lhigh myeloid-biased HSPCs have an increased dependency on oxidative phosphorylation and glucose metabolism. Importantly, metabolism actively regulates immune-cell production, with overexpression of the glucose-6-phosphate dehydrogenase enzyme of the pentose phosphate pathway skewing MPP output from B-lymphocytes towards the myeloid lineages, and expansion of CD62Lhigh HSPCs occurring to support emergency myelopoiesis. Collectively, our data reveal the metabolic cues that instruct innate immune cell development, highlighting a key role for the pentose phosphate pathway. More broadly, our results show that HSPC metabolism can be manipulated to alter the cellular composition of the immune system.

immunology↗

bioRxiv2019

Screening of clustered regulatory elements reveals functional cooperating dependencies in Leukemia.

In the recent years, massively parallel sequencing approaches identified hundreds of mutated genes in cancer(1) providing an unprecedented amount of information about mechanisms of cancer cell maintenance and progression. However, while (it is widely accepted that) transformation processes result from oncogenic cooperation between deregulated genes and pathways, the functional characterization of candidate key players is mostly performed at the single gene level which is generally inadequate to identify these oncogene circuitries. In addition, studies aimed at depicting oncogenic cooperation involve the generation of challenging mouse models or the deployment of tedious screening pipelines. Genome wide mapping of epigenomic modifications on histone tails or binding of factors such as MED1 and BRD4 allowed identification of clusters of regulatory elements, also termed Super-Enhancers (SE)(2). Functional annotation of these regions revealed their high relevance during normal tissue development and cancer ontogeny(3). An interesting paradigm of the tumorigenic function of these SE regions comes from ETO2-GLIS2-driven acute megakaryoblastic leukemia (AMKL) in which the fusion protein ETO2-GLIS2 is sufficient to promote an aberrant transcriptional network by the rewiring of SE regions(4). We thus hypothesized that important regulatory regions could control simultaneously expression of genes cooperating in functional modules to promote cancer development. In an effort to identify such modules, we deployed a genome-wide CRISPRi-based screening approach and nominated SE regions that are functionally linked to leukemia maintenance. In particular, we pinpointed a novel SE region regulating the expression of both tyrosine kinases KIT and PDGFRA. Whereas the inhibition of each kinase alone affected modestly cancer cell growth, combined inhibition of both receptors synergizes to impair leukemia cell growth and survival. Our results demonstrate that genome-wide screening of regulatory DNA elements can identify co-regulated genes collaborating to promote cancer and could open new avenues to the concept of combined gene inhibition upon single hit targeting.

cancer biology↗

bioRxiv2019

Splicing inhibition enhances the antitumor immune response through increased tumor antigen presentation and altered MHC-I immunopeptidome

The success of cancer immunotherapy relies on the induction of an immunoprotective response targeting tumor antigens (TAs) presented by tumor cells on MHC class I molecules. Alternative translation events emerged as a rich source of TAs and generate the so-called Pioneer Translation Products (PTPs), which are peptides generated from unspliced mRNA. We demonstrated in vitro and in vivo that the splicing inhibitor isoginkgetin and a derived water-soluble and less toxic molecule, IP2, act at the production stage of the PTPs. We showed that IP2 increases PTP-derived antigen presentation in cancer cells in vitro and decreases tumor growth in vivo in an immune-dependent manner. Furthermore, IP2 treatment induces a long-lasting antitumor response. Finally, we observed that the epitope repertoire displayed on MHC-I molecules is altered upon treatment with IP2 with the modulation of pre-existing peptides and the emergence of novel antigens derived from both coding and allegedly non-coding sequences.\n\nSignificanceIP2 is a new efficient \"first in class\" immunomodulator of the MHC I presentation pathway. IP2 reduces the growth of sarcoma MCA205 and melanoma B16F10 tumors bearing the PTP-derived SL8 epitope and significantly extends mice survival. IP2 treatment reshape the cancer cell MHC-I immunopeptidome. These findings add to the understanding of the role of the splicing machinery in antigen production and presentation and identify the spliceosome as a druggable target to enhance cancer immunosurveillance.

immunology↗