Biology subjects

Peel, S.

Publications and source records attributed to Peel, S..

3 recordsLinked to original sources

bioRxiv2022

Nuclear fascin regulates cancer cell survival

Fascin is an important regulator of F-actin bundling leading to enhanced filopodia assembly. Fascin is also overexpressed in most solid tumours where it supports invasion through control of F-actin structures at the periphery and nuclear envelope. Recently fascin has been identified in the nucleus of a broad range of cell types but the contributions of nuclear fascin to cancer cell behaviour remain unknown. Here we demonstrate that fascin bundles F-actin within the nucleus to support chromatin organisation and efficient DNA damage response. Fascin associates directly with phosphorylated Histone H3 leading to regulated levels of nuclear fascin to support these phenotypes. Forcing nuclear fascin accumulation through the expression of nuclear-targeted fascin-specific nanobodies or inhibition of Histone H3 kinases results in enhanced and sustained nuclear F-actin bundling leading to reduced invasion, viability and nuclear fascin-specific/driven apoptosis. These findings represent an additional important route through which fascin can support tumorigenesis and provide insight into potential pathways for targeted fascin-dependent cancer cell killing.

cancer biology↗

bioRxiv2020

Mutational inactivation of Apc in the intestinal epithelia compromises cellular organisation

The tumour suppressor adenomatous polyposis coli (Apc) regulates diverse effector pathways essential for cellular homeostasis. Truncating mutations in Apc, leading to the loss of its Wnt pathway and microtubule regulatory domains, are oncogenic in human and murine intestinal epithelia and drive malignant transformation. Whereas uncontrolled proliferation via Wnt pathway deregulation is an unequivocal consequence of oncogenic Apc mutations, it is not known whether loss of its other control systems contribute to tumorigenesis. Here we employ in vitro models of tumorigenesis to unmask the molecular barriers erected by Apc that maintain normal epithelial homeostasis in the murine intestinal epithelia. We determine that (i) enterocyte proliferation, (ii) microtubule dynamics and (iii) epithelial morphology are controlled by three independent molecular pathways, each corrupted by oncogenic Apc mutations. The key result of the study is to establish that Apc regulates three individual biological fates in the intestinal epithelia, through three distinct effector pathways, a significant advance to our understanding of normal tissue homeostasis, the molecular architecture of epithelial tissue and the aetiology of intestinal cancer.

cell biology↗

bioRxiv2019

Segmenting nuclei in brightfield images with neural networks

Identifying nuclei is a standard first step to analysing cells in microscopy images. The traditional approach relies on signal from a DNA stain, or fluorescent transgene expression localised to the nucleus. However, imaging techniques that do not use fluorescence can also carry useful information. Here, we demonstrate that it is possible to accurately segment nuclei directly from brightfield images using deep learning. We confirmed that three convolutional neural network architectures can be adapted for this task, with U-Net achieving the best overall performance, Mask R-CNN providing an additional benefit of instance segmentation, and DeepCell proving too slow for practical application. We found that accurate segmentation is possible using as few as 16 training images and that models trained on images from similar cell lines can extrapolate well. Acquiring data from multiple focal planes further helps distinguish nuclei in the samples. Overall, our work liberates a fluorescence channel reserved for nuclear staining, thus providing more information from the specimen, and reducing reagents and time required for preparing imaging experiments.

bioinformatics↗