Professor Andrew David Hamilton Wyllie – Biographical Memoir

Andrew Wyllie graduated from Aberdeen University, becoming an academic pathologist in Aberdeen, Edinburgh and Cambridge. He was the co-discoverer of apoptotic cell death having observed single cells dying following carcinogen exposure. Together with Alastair Currie and John Kerr, he realised the profound importance of this novel mode of cell death that showed a distinctive series of morphological changes, which he first described as a new cell death process. Wyllie and Currie introduced the term “apoptosis” for this cell death process in a seminal paper in 1972. Another landmark discovery was of chromatin fragmentation in apoptosis, due to activation of an endogenous endonuclease that caused internucleosomal DNA cleavage (“chromatin laddering”), which was the first biochemical mechanism of apoptosis. He further characterised chromatin fragmentation in the 1980s, followed by investigations of cell surface changes to produce “eat-me” signals to trigger rapid phagocytosis of the apoptotic cells and bodies, intracellular calcium ion signalling, caspase activation and other mechanisms of apoptosis. His cancer research helped identify the location of APC and generated his demonstration that apoptosis was regulated by oncogenes, MYC and RAS, and tumour suppressor genes, such as TP53. He showed how apoptosis occurred in response to DNA damage and was a key process influencing both carcinogenesis and tumour growth. Andrew made a major scientific observation that changed the understanding of how cells die in health and disease, although it took time for the scientific establishment to understand its fundamental importance. Andrew Wyllie is widely known as the ‘Father of Apoptosis’

Activation of K-RAS by co-mutation of codons 19 and 20 is transforming.

The K-RAS oncogene is widely mutated in human cancers. Activating mutations in K-RAS give rise to constitutive signalling through the MAPK/ERK and PI3K/AKT pathways promoting increased cell division, reduced apoptosis and transformation. The majority of activating mutations in K-RAS are located in codons 12 and 13. In a human colorectal cancer we identified a novel K-RAS co-mutation that altered codons 19 and 20 resulting in transitions at both codons (L19F/T20A) in the same allele. Using focus forming transformation assays in vitro , we showed that co-mutation of L19F/T20A in K-RAS demonstrated intermediate transforming ability that was greater than that of individual L19F and T20A mutants, but less than that of G12D and G12V K-RAS mutants. This demonstrated the synergistic effects of co-mutation of codons 19 and 20 and illustrated that co-mutation of these codons is functionally significant.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

Mouse models of colorectal cancer as preclinical models.

In this review, we discuss the application of mouse models to the identification and pre-clinical validation of novel therapeutic targets in colorectal cancer, and to the search for early disease biomarkers. Large-scale genomic, transcriptomic and epigenomic profiling of colorectal carcinomas has led to the identification of many candidate genes whose direct contribution to tumourigenesis is yet to be defined; we discuss the utility of cross-species comparative 'omics-based approaches to this problem. We highlight recent progress in modelling late-stage disease using mice, and discuss ways in which mouse models could better recapitulate the complexity of human cancers to tackle the problem of therapeutic resistance and recurrence after surgical resection.REM, SJAB, MJA and DJA are funded by Cancer Research UK.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/bies.20150003

Inflammatory bowel disease-associated colorectal cancer: translational risks from mechanisms to medicines

The cumulative impact of chronic inflammation in patients with inflammatory bowel diseases predisposes to the development of inflammatory bowel disease-associated colorectal cancer [IBD-CRC]. Inflammation can induce mutagenesis, and the relapsing–remitting nature of this inflammation, together with epithelial regeneration, may exert selective pressure accelerating carcinogenesis. The molecular pathogenesis of IBD-CRC, termed the ‘inflammation–dysplasia–carcinoma’ sequence, is well described. However, the immunopathogenesis of IBD-CRC is less well understood. The impact of novel immunosuppressive therapies, which aim to achieve deep remission, is mostly unknown. Therefore, this timely review summarizes the clinical context of IBD-CRC, outlines the molecular and immunological basis of disease pathogenesis, and considers the impact of novel biological therapies

Rapid Artefact Removal and H&E-Stained Tissue Segmentation

We present an innovative method for rapidly segmenting hematoxylin and eosin (H&E)-stained tissue in whole-slide images (WSIs) that eliminates a wide range of undesirable artefacts such as pen marks and scanning artefacts. Our method involves taking a single-channel representation of a lowmagnification RGB overview of the WSI in which the pixel values are bimodally distributed suchthat H&E-stained tissue is easily distinguished from both background and a wide variety of artefacts. We demonstrate our method on 30 WSIs prepared from a wide range of institutions and WSI digital scanners, each containing substantial artefacts, and compare it to segmentations provided by Otsu thresholding and Histolab tissue segmentation and pen filtering tools. We found that our methodsegmented the tissue and fully removed all artefacts in 29 out of 30 WSIs, whereas Otsu thresholding failed to remove any artefacts, and the Histolab pen filtering tools only partially removed the pen marks. The beauty of our approach lies in its simplicity: manipulating RGB colour space and using Otsu thresholding allows for the segmentation of H&E-stained tissue and the rapid removal ofartefacts without the need for machine learning or parameter tuning

Acute sensitivity of the oral mucosa to oncogenic K-ras.

Mouse models of cancer represent powerful tools for analysing the role of genetic alterations in carcinogenesis. Using a mouse model that allows tamoxifen-inducible somatic activation (by Cre-mediated recombination) of oncogenic K-ras(G12D) in a wide range of tissues, we observed hyperplasia of squamous epithelium located in moist or frequently abraded mucosa, with the most dramatic effects in the oral mucosa. This epithelium showed a sequence of squamous hyperplasia followed by squamous papilloma with dysplasia, in which some areas progressed to early invasive squamous cell carcinoma, within 14 days of widespread oncogenic K-ras activation. The marked proliferative response of the oral mucosa to K-ras(G12D) was most evident in the basal layers of the squamous epithelium of the outer lip with hair follicles and wet mucosal surface, with these cells staining positively for pAKT and cyclin D1, showing Ras/AKT pathway activation and increased proliferation with Ki-67 and EdU positivity. The stromal cells also showed gene activation by recombination and immunopositivity for pERK indicating K-Ras/ERK pathway activation, but without Ki-67 positivity or increase in stromal proliferation. The oral neoplasms showed changes in the expression pattern of cytokeratins (CK6 and CK13), similar to those observed in human oral tumours. Sporadic activation of the K-ras(G12D) allele (due to background spontaneous recombination in occasional cells) resulted in the development of benign oral squamous papillomas only showing a mild degree of dysplasia with no invasion. In summary, we show that oral mucosa is acutely sensitive to oncogenic K-ras, as widespread expression of activated K-ras in the murine oral mucosal squamous epithelium and underlying stroma can drive the oral squamous papilloma-carcinoma sequence