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Biology subjects

Cumming, E. M.

Publications and source records attributed to Cumming, E. M..

4 recordsLinked to original sources

Glandular architecture and malignant behaviour in colorectal cancer is regulated by the sialomucin Podocalyxin.

Glandular architecture-the coordination of lumen-containing structures by an apical-basal polarised epithelium-is frequently maintained in colorectal cancer (CRC), yet whether it actively contributes to tumour progression or metastatic competence remains unclear. Here, we identify Podocalyxin (PODXL), a developmental regulator of epithelial lumen formation, as a key determinant of glandular tumour architecture in CRC. PODXL is upregulated in CRC, particularly in poor-prognosis Consensus Molecular Subtype 4 (CMS4) tumours, where high expression predicts reduced survival. Using genetically engineered mouse models, matched organoids, human cell lines and xenografts, we show that PODXL promotes organisation of CRC cells into gland-like, lumen-containing structures. Loss of PODXL disrupts glandular architecture in both primary tumours and liver metastases, reducing tumour growth and metastatic colonisation. Mechanistically, TGF-{beta} signalling drives PODXL upregulation. Together, these findings establish glandular architecture as an active determinant of CRC progression and identify PODXL as a functional contributor rather than merely a prognostic biomarker.

cancer biology↗

Population-scale sequencing resolves correlates and determinants of latent Epstein-Barr Virus infection

Epstein-Barr Virus (EBV) is an endemic herpesvirus implicated in autoimmunity, cancer, and neurological disorders. Though primary infection typically resolves with subclinical symptoms, long-term complications can arise due to immune dysregulation or viral latency, in which EBV DNA is detectable in blood for decades. Despite the ubiquity of this virus, we have an incomplete understanding of the highly variable responses to EBV that range from asymptomatic infection to a trigger for severe disease. Here, we demonstrate that existing whole genome sequencing (WGS) data contains ample non-human DNA sequences to reconstruct a molecular biomarker of latent EBV infection consistent with orthogonal phenotypes, including viral serology. Using the UK Biobank (n = 490,560) and All of Us (n = 245,394), we uncover reproducible complex trait associations that nominate latent blood-derived EBV DNA as a respiratory, autoimmune, and cardiovascular disease biomarker. Further, we evaluate the genetic determinants of persistent EBV DNA via genome-wide and exome-wide association studies, uncovering protein-altering variants from 147 genes. Single-cell and pathway-scale enrichment analyses implicate variable antigen processing and presentation as a primary genetic determinant of latent EBV persistence, with gene programs expressed in B cells and antigen-presenting cells. Using predicted viral epitope presentation affinities, we implicate genetic variation in MHC class II as a key modulator of EBV DNA persistence. Our analyses demonstrate how existing WGS data can derive novel molecular biomarkers, which may generalize to dozens of viruses comprising the blood virome1.

genetics↗

PTEN deficiency exposes a requirement for an ARF GTPase module in integrin-dependent invasion in ovarian cancer.

Dysregulation of the PI3K/AKT pathway is a common occurrence in ovarian carcinomas. Loss of the tumour suppressor PTEN in high-grade serous ovarian carcinoma (HGSOC) is associated with a patient subgroup with poor prognosis. The cellular mechanisms of how PTEN loss contributes to HGSOC are largely unknown. We utilise long-term time-lapse imaging of HGSOC spheroids coupled to a machine learning approach to classify the phenotype of PTEN loss. PTEN deficiency does not affect proliferation but rather induces PI(3,4,5)P3-rich and -dependent membrane protrusions into the extracellular matrix (ECM), resulting in a collective invasion phenotype. We identify the small GTPase ARF6 as a crucial vulnerability upon PTEN loss. Through a functional proteomic CRISPR screen of ARF6 interactors, we identify the ARF GTPase-activating protein (GAP) AGAP1 and the ECM receptor {beta}1-integrin (ITGB1) as key ARF6 interactors regulating the PTEN loss-associated invasion phenotype. ARF6 functions to promote invasion by controlling the recycling of internalised, active {beta}1-integrin complexes to maintain invasive activity into the ECM. The expression of the ARF6-centred complex in HGSOC patients is inversely associated with outcome, allowing identification of patient groups with improved versus poor outcome. ARF6 may represent a new therapeutic vulnerability in PTEN- depleted HGSOC tumours.

cancer biology↗

Spatial regulation of the glycocalyx component Podocalyxin is a switch for pro-metastatic function

The glycocalyx component and sialomucin Podocalyxin (PODXL) is required for normal tissue development by promoting apical membranes to form between cells, triggering lumen formation. Elevated PODXL expression is also associated with metastasis and poor clinical outcome in multiple tumour types. How PODXL presents this duality in effect remains unknown. We identify an unexpected function of PODXL as a decoy receptor for Galectin-3 (GAL3), whereby the PODXL-GAL3 interaction releases GAL3 repression of integrin-based invasion. Differential cortical targeting of PODXL, regulated by ubiquitination, is the molecular mechanism controlling alternate fates. Both PODXL high versus low surface levels occur in parallel subpopulations within cancer cells. Orthotopic intraprostatic xenograft of PODXL-manipulated cells or those with different surface levels of PODXL define that this axis controls metastasis in vivo. Clinically, interplay between PODXL-GAL3 stratifies prostate cancer patients with poor outcome. Our studies define the molecular mechanisms and context in which PODXL promotes invasion and metastasis.

cell biology↗