Biology subjects

Bourne, C.

Publications and source records attributed to Bourne, C..

3 recordsLinked to original sources

bioRxiv2023

Host-cell Interactions of Engineered T cell Micropharmacies

Genetically engineered, cytotoxic, adoptive T cells localize to antigen positive cancer cells inside patients, but tumor heterogeneity and multiple immune escape mechanisms have prevented the eradication of most solid tumor types. More effective, multifunctional engineered T cells are in development to overcome the barriers to the treatment of solid tumors, but the interactions of these highly modified cells with the host are poorly understood. We previously engineered prodrug-activating enzymatic functions into chimeric antigen receptor (CAR) T cells, endowing them with an orthogonal killing mechanism to conventional T-cell cytotoxicity. These drug-delivering cells, termed Synthetic Enzyme-Armed KillER (SEAKER) cells, demonstrated efficacy in mouse lymphoma xenograft models. However, the interactions of an immunocompromised xenograft with such complex engineered T cells are distinct from those in an immunocompetent host, precluding an understanding of how these physiologic processes may affect the therapy. Here, we also expand the repertoire of SEAKER cells to target solid-tumor melanomas in syngeneic mouse models using specific targeting with TCR-engineered T cells. We demonstrate that SEAKER cells localize specifically to tumors, and activate bioactive prodrugs, despite host immune responses. We additionally show that TCR-engineered SEAKER cells are efficacious in immunocompetent hosts, demonstrating that the SEAKER platform is applicable to many adoptive cell therapies.

immunology↗

bioRxiv2020

Low-Dose CDK4/6 Inhibitors Induce Presentation of Pathway Specific MHC ligands as Targets for Cancer Immunotherapy

PurposeCyclin dependent kinase 4/6 inhibitors (CDK4/6i) lead to cell-cycle arrest but also demonstrate antineoplastic activity through triggering T cell-mediated immunity. One of the potential mechanisms responsible for this immunological effect might be qualitative and quantitative changes in human leukocyte antigen (HLA) ligands on the cell surface after treatment with CDK4/6i. These changes may increase the immunogenicity of breast cancer cells offering potential synergies for combinations with cancer immunotherapies. Experimental DesignWe investigated the ability of two CDK4/6 inhibitors (CDK4/6i), Abemaciclib and Palbociclib, to alter the immunopeptidome at subclinical, non-toxic, levels in different breast cancer cell lines. Biochemical isolation of HLA ligands, identification by mass spectrometry and subsequent network analysis after drug treatment were used to characterize the changes in the immunopeptidome. The mechanisms for altered CDK4/6 presentation were explored. ResultsLow-dose treatment with 100nM of Abemaciclib and Palbociclib led to upregulation of cell surface HLA levels and induced hundreds of HLA ligands in breast cancer cell lines. These new ligands were significantly and most strongly enriched for peptides derived from proteins involved in the "G1/S phase transition of cell cycle" pathway and included among others, HLA ligands from CDK4, CDK6, Cyclin D1 and Cyclin E1. An increase in transcript, protein, and subsequent ubiquitination for Cyclin D1, which could lead to enhanced degradation of the target protein, was identified as a potential mechanism for the altered presentation of peptides. ConclusionsCDK4/6i treatment gave rise to drug-induced antigens through cell cycle disruption and increased antigen presentation. Interestingly, these induced HLA ligands are often sourced from the proteins of the CDK4/CDK6/CCND1 complex or more downstream interaction partners, providing evidence that inhibition of a distinct cellular pathway leads to increased presentation of the proteins involved. These findings suggested CDK4/6i provided a tool for highly selective induction of HLA ligands that may be targeted by T cell-based immunotherapeutics. Translational RelevanceThese data demonstrated that low-dose treatment of breast cancer cells with CDK4/6 inhibitors, Abemaciclib and Palbociclib, induced marked changes in presentation of HLA ligands, especially from proteins involved in the G1/S phase transition, the phase in which these drugs arrest the cells. Enhanced ubiquitination and degradation was identified as a mechanism for the altered presentation for one of the relevant proteins. The induced HLA ligands may provide ideal specific targets for combination immunotherapies. The data show for the first time that selective inhibition of a distinct pathway can lead to specific presentation of HLA ligands in breast cancer cells. This work supports the rationale for testing the combination of low-dose CDK4/6i with immunotherapeutic agents, such as immune checkpoint blockade antibodies or T-cell-based approaches specifically directed against one of the induced HLA ligands.

cancer biology↗

bioRxiv2019

Adaptation to seasonal reproduction and thermal minima-related factors drives fine-scale divergence despite gene flow in Atlantic herring populations

Natural selection can maintain local adaptation despite the presence of gene flow. However, the genomic basis and environmental factors involved in adaptation at fine-spatial scales are not well understood. Here, we address these questions using Atlantic herring (Clupea harengus), an abundant, migratory, and widely distributed marine species with substantial genomic resources including a chromosome-level genome assembly and genomic data from the eastern Atlantic and Baltic populations. We analysed whole-genome sequence and oceanographic data to examine the genetic variation of 15 spawning aggregations across the northwest Atlantic Ocean ([~]1,600 km of coastline) and the association of this variation with environmental variables. We found that population structure lies in a small fraction of the genome involving adaptive genetic variants of functional importance. We discovered 10 highly differentiated genomic regions distributed across four chromosomes. Two of these loci appear to be private to the northwest, four loci share a large number of adaptive variants between northwest and northeast Atlantic, and four shared loci exhibit an outstanding diversity in haplotype composition, including a novel putative inversion on chromosome 8. Another inversion on chromosome 12 underlies a latitudinal genetic pattern discriminating populations north and south of a biogeographic transition zone on the Scotian Shelf. Our genome-environment association analysis indicates that sea water temperature during winter is the environmental factor that best correlates with the latitudinal pattern of this inversion. We conclude that the timing and geographic location of spawning and early development are under diverse selective pressures related to environmental gradients. Natural selection appears to act on early-life performance traits with differential fitness across environments. Our study highlights the role of genomic architecture, ancestral haplotypes, and selection in maintaining adaptive divergence in species with large population sizes and presumably high gene flow.

genomics↗