Biology subjects

Arnold, J. N.

Publications and source records attributed to Arnold, J. N..

5 recordsLinked to original sources

bioRxiv2023

The translation of a short open reading frame product within the human TUBA1B gene regulates cancer cell proliferation by importin-β

Understanding cancer biology is crucial for improving treatment strategies. This study identified TUBA1B-sORF1, a short open reading frame product alternatively translated from the human -tubulin gene (TUBA1B), which has a completely different amino acid sequence from the -tubulin 1B chain. TUBA1B-sORF1 is highly expressed in cancer cell lines and gastric carcinoma. Both methionine-initiated canonical and leucine-initiated noncanonical translations of TUBA1B-sORF1 coexist in cancer cells, and there is a transition between sORF1 and -tubulin translations, evidenced by the TUBA1B-sORF1/-tubulinlow/- subpopulation. Knocking down TUBA1B-sORF1 reduces cancer cell proliferation and tumorigenicity. TUBA1B-sORF1 facilitates protein nuclear translocation, leading to the upregulation of proliferation-promoting genes and downregulation of proliferation-inhibiting genes. Specifically, it forms a complex with importin {beta} and {beta}-catenin, promoting {beta}-catenin nuclear translocation and target gene transcription. These findings reveal that TUBA1B is a polycistronic gene translating at least two entirely different proteins: -tubulin and TUBA1B-sORF1. The variable translation between them may regulate tumorigenesis, making TUBA1B-sORF1 a promising therapeutic target and diagnostic biomarker for cancer treatment.

cancer biology↗

bioRxiv2023

Heme oxygenase-1 expressing omental macrophages as a therapeutic target in ovarian high grade serous carcinoma

Ovarian high grade serous carcinoma (HGSC) remains a disease of poor prognosis that is unresponsive to current immune checkpoint inhibitors. Although PI3K pathway alterations are common in HGSC, attempts to target this pathway have been unsuccessful. We hypothesised aberrant PI3K pathway activation may alter the HGSC immune microenvironment and present a novel targeting strategy. We used both murine models and HGSC patient samples to study the impact of loss of Pten, a negative regulator of PI3K pathway signalling. We identified populations of resident macrophages specifically in Pten null omental tumours. These macrophages derive from peritoneal fluid macrophages and have a unique gene expression programme, marked by high levels of HMOX1 expression, the gene for the enzyme heme oxygenase-1. Targeting resident peritoneal macrophages prevents appearance of HMOX1hi macrophages and in doing so reduces tumour growth. Furthermore, direct inhibition of HMOX1 extends survival in vivo. HMOX1hi macrophages with corresponding gene expression programmes are also identified in human HGSC tumours and their presence correlates with activated tumoural PI3K pathway/mTOR signalling and poor overall survival in HGSC patients. In contrast, tumours with low number of HMOX1hi macrophages are marked by increased adaptive immune response gene expression. Our data suggest that HMOX1hi macrophages represent a potential therapeutic target and biomarker for poor prognosis HGSC.

cancer biology↗

bioRxiv2022

Perivascular macrophages collaborate to facilitate chemotherapy resistance in cancer

A subset of tumor associated macrophages (TAMs) identified by their expression of the lymphatic vessel endothelial hyaluronan receptor-1 (Lyve-1) reside proximal to blood vasculature and contribute to disease progression. Using a spontaneous murine model of mammary adenocarcinoma (MMTV-PyMT), we show that Lyve-1+ TAMs, which co-express heme oxygenase-1, form coordinated multi-cellular nest structures in the perivascular niche. We show that TAM nest formation is dependent on IL-6 and a communication axis involving CCR5 and its cognate ligands CCL3/4. We demonstrate that Lyve-1+ TAM nests are associated with CD8+ T-cell exclusion from the tumor and the resistance to immune-stimulating chemotherapeutics. This study highlights an unappreciated collaboration between TAMs and uncovers a spatially driven therapeutic resistance mechanism of these cells in cancer which can be therapeutically targeted.

cancer biology↗

bioRxiv2020

Lyve-1 expressing perivascular macrophages orchestrate pericyte expansion to sustain angiogenesis in cancer

Tumor associated macrophages (TAMs) are a highly plastic stromal cell type which support cancer progression. Using single-cell RNA-sequencing of TAMs from a spontaneous murine model of mammary adenocarcinoma (MMTV-PyMT) we characterize a subset of these cells expressing lymphatic vessel endothelial hyaluronic acid receptor 1 (Lyve-1) which spatially reside proximal to blood vasculature. We demonstrate that Lyve-1+ TAMs support tumor growth and identify a pivotal role for these cells in maintaining a population of perivascular mesenchymal cells which express alpha-smooth muscle actin and phenotypically resemble pericytes. Using photolabeling techniques show that mesenchymal cells maintain their prevalence in the growing tumor through proliferation and uncover a role for Lyve-1+ TAMs in orchestrating a selective platelet-derived growth factor-CC-dependent expansion of the perivascular mesenchymal population, creating a pro-angiogenic niche. This study highlights the inter-reliance of the immune and non-immune stromal network which support cancer progression and provides therapeutic opportunities for tackling the disease.

cancer biology↗

bioRxiv2020

ImmunoCluster: A computational framework for the non-specialist to immune profile cellular heterogeneity using liquid and imaging mass, and flow cytometry datasets

High dimensional cytometry is an innovative tool for immune monitoring in health and disease, it has provided novel insight into the underlying biology as well as biomarkers for a variety of diseases. However, the analysis of multiparametric "big data" usually requires specialist computational knowledge. Here we describe ImmunoCluster (https://github.com/kordastilab/ImmunoCluster) an R package for immune profiling cellular heterogeneity in high dimensional liquid and imaging mass cytometry, and flow cytometry data, designed to facilitate computational analysis by a non-specialist. The analysis framework implemented within ImmunoCluster is readily scalable to millions of cells and provides a variety of visualization and analytical approaches, as well as a rich array of plotting tools that can be tailored to users needs. The protocol consists of three core computational stages: 1, data import and quality control, 2, dimensionality reduction and unsupervised clustering; and 3, annotation and differential testing, all contained within an R-based open-source framework.

systems biology↗