Biology subjects

Harwood, C. A.

Publications and source records attributed to Harwood, C. A..

3 recordsLinked to original sources

bioRxiv2023

A CD24+CD271+ melanoma cancer stem cell generates a diffuse hierarchy of attributes that promote metastasis and therapeutic resistance

An important role for phenotype switching has been demonstrated in metastasis and therapeutic resistance of both melanoma and epithelial tumours. Phenotype switching in epithelial tumours is driven by a minority cancer stem cell sub-population with lineage plasticity, but such a sub-population has not been identified in melanoma. We investigated whether cell surface markers used to identify cancer stem cells in epithelial tumours could identify a cancer stem cell sub-population with lineage plasticity in melanoma. We identified a CD24+CD271+ minority sub-population in melanoma that possesses the stem cell characteristics of lineage plasticity and self-renewal. This population displayed hybrid characteristics, combining the attributes of discrete CD24+ and CD271+ cellular sub-populations but with heightened sphere formation, lineage plasticity, migratory ability and drug resistance over its single-marker counterparts. CD24+ and CD24+CD271+ stem cell sub-populations were observed in 10% of human melanomas, mainly at the invasive front. The lack of CD24+ and CD24+CD271+ stem cells in the majority of human melanoma specimens led us to conclude that they may be dispensable for melanoma progression. Nevertheless, the enhanced sphere formation, lineage plasticity, migratory ability and drug resistance of the CD24+CD271+ sub-population may signal a contextual requirement for these stem cells when melanomas face challenging environments both clinically and in experimental systems.

cancer biology↗

bioRxiv2019

Inherited duplications of PPP2R3B promote naevi and melanoma via a novel C21orf91-driven proliferative phenotype

The majority of the heredity of melanoma remains unexplained, however inherited copy number changes have not yet been systematically studied. The genetic environment is highly relevant to treatment stratification, and new gene discovery is therefore desirable. Using an unbiased whole genome screening approach for copy number we identify here a novel melanoma predisposing factor, familial duplications of gene PPP2R3B, encoding a regulatory unit of critical phosphatase PP2A. Significant correlation between expression of PPP2R3B in tumour tissue and survival in a large melanoma cohort was confirmed, and associated with a non-immunological expression profile. Mechanistically, construction and extensive characterization of a stable, inducible cellular model for PPP2R3B overexpression revealed induction of pigment cell switching towards proliferation and away from migration. Importantly, this was independent of the known microphthalmia-associated transcription factor (MITF)-controlled pigment cell phenotype switch, and was instead driven by uncharacterised gene C21orf91. Bioinformatic studies point to C21orf91as a novel target of MITF, and therefore a potential hub in the control of phenotype switching in melanoma. This study identifies novel germline copy number variants in PPP2R3B predisposing to melanocytic neoplasia, and uncovers a new potential therapeutic target C21orf91 in the control of pigment cell proliferation.

genomics↗

bioRxiv2018

The Pemphigus Vulgaris antigen desmoglein-3 suppresses p53 function via the YAP-Hippo pathway

Desmoglein-3 (Dsg3), the Pemphigus Vulgaris (PV) antigen (PVA), plays an essential role in keratinocyte cell-cell adhesion and regulates various signaling pathways implicated in the pathogenesis the PV blistering disease. We show here that expression of Dsg3 may directly influence p53, a key transcription factor governing the response to cellular stress. Dsg3 depletion caused increased p53 and apoptosis, an effect that was further enhanced by UV and mechanical strain and reversed by Dsg3 gain-of-function studies. Analysis in Dsg3-/- mouse skin confirmed increased p53/p21/caspase-3 compared to Dsg3+/- control in vivo. This Dsg3-p53 pathway involved YAP since Dsg3 forms a complex with YAP and regulates its expression and localization. Analysis of PV patient samples detected increased p53/YAP with diffuse cytoplasmic and/or nuclear staining in cells surrounding blisters. Treatment of keratinocytes with PV sera evoked pronounced p53/YAP expression. Collectively, our findings establish a novel role for Dsg3 as an anti-stress protein, via suppression of p53 function, suggesting that this pathway, involving YAP-Hippo control of skin homeostasis, is disrupted in PV.

cell biology↗