Biology subjects

Perna, F.

Publications and source records attributed to Perna, F..

3 recordsLinked to original sources

bioRxiv2024

CD4+Foxp3E2+ regulatory T cell frequency predicts breast cancer prognosis and recurrence

CD4+Foxp3+ regulatory T cells (Tregs) are key to maintain peripheral self-tolerance and suppress immune responses to tumors. Their accumulation in the tumor microenvironment (TME) correlates with poor clinical outcome in several human cancers, including breast cancer (BC). However, the properties of intratumoral Tregs remain largely unknown. Here, we found that a functionally distinct subpopulation of tumor-infiltrating Tregs, which express the Foxp3 splicing variant retaining exon 2 (Foxp3E2), is prominent in the TME and peripheral blood of hormone receptor- positive (HR+) BC subjects with poor prognosis. Notably, a comprehensive examination of the Tumor Cell Genome Atlas (TCGA) validated Foxp3E2 as an independent prognostic marker in all other BC subtypes. We found that FOXP3E2 expression underlies BCs with highly immune suppressive landscape, defective mismatch repair and a stem-like signature thus highlighting pathways involved in tumor immune evasion. Finally, we confirmed the higher immunosuppressive capacity of BC patients-derived Foxp3E2+ Tregs by functional assays. Our study suggests Foxp3E2+ Tregs might be used as an independent biomarker to predict BC prognosis and recurrence, and to develop super-targeted depletion-based immunotherapies. One-sentence summariesFoxp3E2+ Treg enrichment reflects an increased tumor-immune suppression and predicts prognosis and recurrence in breast cancer.

immunology↗

bioRxiv2023

The expression profile and tumorigenic mechanisms of CD97 (ADGRE5) in glioblastoma render it a targetable vulnerability

Glioblastoma (GBM) is the most common and aggressive primary brain malignancy. Adhesion G protein-coupled receptors (aGPCRs) have attracted interest for their functional role in gliomagenesis and their potential as treatment targets. To identify therapeutically targetable opportunities among aGPCR family members in unbiased fashion, we analyzed expression levels of all aGPCRs in GBM and non-neoplastic brain tissue. Using bulk and single cell transcriptomic and proteomic data, we show that CD97 (ADGRE5), an aGPCR previously implicated in GBM pathogenesis, is the most promising aGPCR target in GBM, by virtue of its abundance in all GBM tumors and its de novo expression profile in GBM compared to normal brain tissue and neural progenitors. CD97 knockdown or knockout significantly reduces the tumor initiation capacity of patient-derived GBM cultures (PDGC) in vitro and in vivo. Transcriptomic and metabolomic data from PDGCs suggest that CD97 promotes glycolytic metabolism. The oncogenic and metabolic effects of CD97 are mediated by the MAPK pathway. Activation of MAPK signaling depends on phosphorylation of the cytosolic C-terminus of CD97 and recruitment of {beta}-arrestin. Using single-cell RNA-sequencing and biochemical assays, we demonstrate that THY1/CD90 is the most likely CD97 ligand in GBM. Lastly, we show that targeting of PDGCs with an anti-CD97 antibody-drug conjugate in vitro selectively kills tumor cells but not human astrocytes or neural stem cells. Our studies identify CD97 as an important regulator of tumor metabolism in GBM, elucidate mechanisms of receptor activation and signaling, and provide strong scientific rationale for developing biologics to target it for therapeutic purposes.

cancer biology↗

bioRxiv2022

Differential Effects of Mutations of Popeye Domain Containing Proteins on Heteromeric Interaction and Membrane Trafficking

BackgroundThe Popeye domain containing (POPDC) genes encode sarcolemma-localised cAMP effector proteins. Mutations in BVES (POPDC1) and POPDC2 have been associated with limb-girdle muscular dystrophy and cardiac arrhythmia. Muscle biopsies of affected patients display impaired membrane trafficking of both POPDC isoforms. MethodsBiopsy material of patients carrying mutations in BVES were immunostained with POPDC antibodies. The interaction of POPDC proteins was investigated by co-precipitation, proximity ligation, bioluminescence resonance energy transfer and bimolecular fluorescence complementation. Site-directed mutagenesis was utilised to map the domains involved in protein interaction. FindingsPatients carrying a novel homozygous variant, BVES (c.547G>T, p.V183F) displayed only a skeletal muscle pathology and a mild impairment of membrane trafficking of both POPDC isoforms. This is in contrast to variants such as BVES p.Q153X or POPDC2 p.W188X, which were associated with a greater impairment of membrane trafficking. Co-transfection analysis in HEK293 cells revealed that POPDC proteins interact with each other through a helix-helix interface located at the C-terminus of the Popeye domain. Site-directed mutagenesis of an array of ultra-conserved hydrophobic residues demonstrated that some of them are required for membrane trafficking of the POPDC1-POPDC2 complex. InterpretationMutations in POPDC proteins that cause an impairment in membrane localisation affect POPDC complex formation while mutations which leave the protein interaction intact likely affect some other essential function of POPDC proteins. FundingThis study was funded by an EPSRC/British Heart Foundation co-funded Imperial Institute of Chemical Biology (ICB) Centre for Doctoral Training (CDT) PhD studentship (EP/S023518/1), a project grant of the British Heart Foundation (PG19/13/34247) and the Deutsche Forschungsgemeinschaft (DE1482/9-1). Research in ContextO_ST_ABSEvidence before this studyC_ST_ABSSeveral biallelic missense and nonsense variants in BVES (POPDC1) have been described and are associated with heart and skeletal muscle disease. Skeletal muscle biopsies of homozygous carriers of these variants display a loss of sarcolemmal localisation of POPDC1 and POPDC2. Added value of this studyWe demonstrate that POPDC1 and POPDC2 form a heteromeric complex and that complex formation is required for plasma membrane trafficking of POPDC proteins. Transfection of different disease variants in HEK293 cells replicates their defective membrane targeting observed in biopsy material. Structural modelling and site-directed mutagenesis identifies an interface of strongly conserved hydrophobic residues in POPDC proteins, which likely mediate the interaction of POPDC proteins. Implications of all the available evidenceThese data provide novel insight into the membrane targeting requirements of POPDC proteins. We recommend testing the membrane targeting properties of any novel variant in POPDC isoforms using a newly developed co-transfection assay in HEK293 cells to characterise its pathogenicity. Our novel insight into the requirement of heterodimerization for proper membrane targeting may also offer novel opportunities to treat patients carrying mutations in POPDC proteins.

genetics↗