Biology subjects

Patchett, A. L.

Publications and source records attributed to Patchett, A. L..

5 recordsLinked to original sources

bioRxiv2025

Identification of Expressed Endogenous Retroviral Element Associated Long Terminal Repeats in Devil Facial Tumour Cells

The Tasmanian devil (Sarcophilus harrisii) population has undergone a major decline in the wild due to the epidemics of two transmissible cancers known as devil facial tumours (DFT1 and DFT2). A multipronged conservation strategy is in place, but a vaccine that prevents devils from developing devil facial tumour disease would be a major step towards recovering the wild devil population. Critical to an effective DFT vaccine are target antigens. Putative non-coding regions of genomes have been identified as potential tumour-specific antigens for human cancer. These non-coding regions include long terminal repeats of endogenous retroviral elements. We identified 11,193 ERV LTR transcripts that were expressed in DFT1 or DFT2 transcriptomes but not in healthy tissue samples. Using a proteogenomic approach, we identified 33 ERV LTR peptides unique to DFT1 and/or DFT2 immunopeptidomes; four of these were validated in subsequent screens with synthetic peptides. Our study shows the potential for ERV LTRs as novel vaccine targets against DFT1 and DFT2. This method can be applied to other species for the development of cancer vaccine targets that may be shared across tumour types. summaryERV LTRs are present in the Tasmanian devil genome and devil facial tumour cell transcriptomes and immunopeptidome.

cancer biology↗

bioRxiv2024

Differentially expressed growth factors and cytokines drive phenotypic changes in transmissible cancers

The Tasmanian devil is threatened by two deadly transmissible Schwann cell cancers. A vaccine to protect Tasmanian devils from both devil facial tumour 1 (DFT1) and devil facial tumour 2 (DFT2), and improved understanding of the cancer cell biology, could support improved conservation actions. Previous transcriptomic analysis has implicated phenotypic cellular plasticity as a potential immune escape and survival mechanism of DFT1 cells. This phenotypic plasticity facilitates transition from a myelinating Schwann cell to a repair Schwann cell phenotype that exhibits mesenchymal characteristics. Here, we have identified cytokines and growth factors differentially expressed across DFT cell phenotypes and investigated their role in driving phenotypic plasticity and oncogenic properties of DFT cells. Our results show that NRG1, IL16, TGF{beta}1, TGF{beta}2 and PDGFAA/AB proteins have significant and distinct effects on the proliferation rate, migratory capacity and/or morphology of DFT cells. Specifically, PDGFR signalling, induced by PDGFAA/AB, was a strong enhancer of cell proliferation and migration, while TGF{beta}1 and TGF{beta}2 induced epithelial-mesenchymal transition (EMT)-like changes, inhibited proliferation and increased migratory capacity. These findings suggest complex interactions between cytokine signalling, phenotypic plasticity, growth and survival of DFTs. Signalling pathways implicated in the propagation of DFT are potential targets for therapeutic intervention and vaccine development for Tasmanian devil conservation.

cancer biology↗

bioRxiv2022

A human adenovirus encoding IFN-γ can transduce Tasmanian devil facial tumour cells and upregulate MHC-I

The devil facial tumour disease (DFTD) has led to a massive decline in the wild Tasmanian devil (Sarcophilus harrisii) population. The disease is caused by two independent devil facial tumours (DFT1 and DFT2). These transmissible cancers have a mortality rate of nearly 100%. An adenoviral vector-based vaccine has been proposed as a conservation strategy for the Tasmanian devil. This study aimed to determine if a human adenovirus serotype 5 could express functional transgenes in devil cells. As DFT1 cells do not constitutively express major histocompatibility complex class I (MHC-I), we developed a replication-deficient adenoviral vector that encodes devil interferon gamma (IFN-{gamma}) fused to a fluorescent protein reporter. Our results show that adenoviral-expressed IFN-{gamma} was able to stimulate upregulation of beta-2 microglobulin, a component of MHC-I, on DFT1, DFT2, and devil fibroblast cell lines. This work suggests that human adenoviruses can serve as vaccine platform for devils and potentially other marsupials.

immunology↗

bioRxiv2020

NLRC5 regulates expression of MHC-I and provides a target for anti-tumor immunity in transmissible cancers

Downregulation of major histocompatibility complex I (MHC-I) on tumor cells is a primary means of immune evasion by many types of cancer. Additionally, MHC-I proteins are a primary target of immune-mediated transplant rejection. Transmissible tumors that overcome allograft rejection mechanisms and evade anti-tumor immunity have killed thousands of wild Tasmanian devils (Sarcophilus harrisii). Interferon gamma (IFNG) upregulates surface MHC-I expression on devil facial tumor (DFT) cells but is not sufficient to induce tumor regressions. Transcriptome analysis of IFNG-treated DFT cells revealed strong upregulation of NLRC5, a master regulator of MHC-I in humans and mice. To explore the role of NLRC5 in transmissible cancers, we developed DFT cell lines that constitutively overexpress NLRC5. Transcriptomic results suggest that the role of NLRC5 as a master regulator of MHC-I is conserved in devils. Furthermore, NLRC5 was shown to drive the expression of many components of the antigen presentation pathway. To determine if MHC-I is a target of allogeneic immune responses, we tested serum from devils with anti-DFT responses including natural DFT regressions against DFT cells. Antibody binding occurred with cells treated with IFNG and overexpressed NLRC5. However, CRISPR/Cas9-mediated knockout of MHC-I subunit beta-2-microglobulin (B2M) eliminated antibody binding to DFT cells. Consequently, MHC-I could be identified as a target for anti-tumor and allogeneic immunity and provides mechanistic insight into MHC-I expression and antigen presentation in marsupials. NLRC5 could be a promising target for immunotherapy and vaccines to protect devils from transmissible cancers and inform development of transplant and cancer therapies for humans.

immunology↗

bioRxiv2019

Immune checkpoint proteins are conserved across 160 million years of evolution and are expressed on transmissible cancers

Immune checkpoint immunotherapy has revolutionized medicine, but translational success for new treatments remains low. Around 40% of humans and Tasmanian devils (Sarcophilus harrisii) develop cancer in their lifetime, compared to less than 10% for most species. Additionally, devils are affected by two of the three known transmissible cancers in mammals. Unfortunately, little is known about of immune checkpoints in devils and other non-model species, largely due to a lack of species-specific reagents. We developed a simple cut-and-paste reagent development method applicable to any vertebrate species and show that immune checkpoint interactions are conserved across 160 million years of evolution. The inhibitory checkpoint molecule CD200 is highly expressed on devil facial tumor cells. We are the first to demonstrate that co-expression of CD200R1 can block CD200 expression. The evolutionarily conserved pathways suggest that naturally occurring cancers in devils and other species can serve as models for understanding cancer and immunological tolerance. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/831404v3_ufig1.gif" ALT="Figure 1"> View larger version (108K): org.highwire.dtl.DTLVardef@14ff10eorg.highwire.dtl.DTLVardef@15acfd4org.highwire.dtl.DTLVardef@102a37dorg.highwire.dtl.DTLVardef@3b726c_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗