Stella Pelengaris's research while affiliated with The University of Warwick and other places

Publications (46)

Article
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Object segmentation and structure localization are important steps in automated image analysis pipelines for microscopy images. We present a convolution neural network (CNN) based deep learning architecture for segmentation of objects in microscopy images. The proposed network can be used to segment cells, nuclei and glands in fluorescence microsco...
Conference Paper
Morphological assessment of glands in histopathology images is very important in cancer grading. However, this is labour intensive, requires highly trained pathologists and has limited reproducibility. Digitisation of tissue slides provides us with the opportunity to employ computers, which are very efficient in repetitive tasks, allowing us to aut...
Article
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The key factors which support re-expansion of beta cell numbers after injury are largely unknown. Insulin-like growth factor II (IGF-II) plays a critical role in supporting cell division and differentiation during ontogeny but its role in the adult is not known. In this study we investigated the effect of IGF-II on beta cell regeneration. We employ...
Data
Raw Data of Beta Cell Mass (mg) in MIG and MIGKO Mice. (DOC)
Data
Raw Data of Beta Cell Number in MIG and MIGKO Mice (from 5 pancreas sections per mouse). (DOC)
Article
Full-text available
Pancreatic beta-cells, which secrete the hormone insulin, are the key arbiters of glucose homeostasis. Defective beta-cell numbers and/or function underlie essentially all major forms of diabetes and must be restored if diabetes is to be cured. Thus, the identification of the molecular regulators of beta-cell mass and a better understanding of the...
Article
Full-text available
The transcription factor MYC is a critical regulator of diverse cellular processes, including both replication and apoptosis. Differences in MYC-regulated gene expression responsible for such opposing outcomes in vivo remain obscure. To address this we have examined time-dependent changes in global gene expression in two transgenic mouse models in...
Data
Supplementary gene expression tables and gene set enrichment analysis results.
Article
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Irreversible arterial damage due to early effects of hypo- or hyperglycaemia could account for the limited success of glucose-lowering treatments in preventing cardiovascular disease (CVD) events. We hypothesised that even brief hypo- or hyperglycaemia could adversely affect arterial gene expression and that these changes, moreover, might not be fu...
Article
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Pregnancy is a normal physiological condition in which the maternal β-cell mass increases rapidly about two-fold to adapt to new metabolic challenges. We have used a lineage tracing of β-cells to analyse the origin of new β-cells during this rapid expansion in pregnancy. Double transgenic mice bearing a tamoxifen-dependent Cre-recombinase construct...
Article
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c-Myc (Myc) is a mediator of glucotoxicity but could also independently compromise β-cell survival and function. We have shown that after Myc activation in adult β-cells in vivo, apoptosis is preceded by hyperglycemia, suggesting glucotoxicity might contribute to Myc-induced apoptosis. To address this question conditional Myc was activated in β-cel...
Article
The challenging problem of computational bioimage analysis receives growing attention from life sciences. Fluorescence microscopy is capable of simultaneously visualizing multiple molecules by staining with different fluorescent dyes. In the analysis of the result multichannel images, segmentation of ROIs resembles only a first step which must be f...
Article
Enzymes involved in the oxidative metabolism of n-6 polyunsaturated fatty acids, like lipoxygenase (LOX) and cyclooxygenase (COX), are significant in the pathogenesis of colorectal cancer. Of these enzymes, 15-LOX-1 is expressed in colon. Aim of this article is to describe the role and regulation of 15-LOX-1 in colorectal cancer and highlight its i...
Article
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Meiotic progression, and the number of oocytes surviving to birth, determine the ovarian reserve, yet the control of prenatal oogenesis is poorly understood. We investigated the effects of genetic background and p53 upon oogenesis in mice. Fetal and neonatal ovaries were analysed in B6CBf1 and B6CBf2 mice from 15.5 to 21 days post-coitum (dpc) and...
Article
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In the last years, bioimaging has turned from qualitative measurements towards a high-throughput and highcontent modality, providing multiple variables for each biological sample analyzed. We present a system which combines machine learning based semantic image annotation and visual data mining to analyze such new multivariate bioimage data. Machin...
Conference Paper
Fluorescence microscopy has regained much attention in the last years especially in the field of systems biology. It has been recognized as a rich source of information extending the existing sources since it allows simultaneous collection of spatial and temporal protein information. In order to enable a high-throughput and high-content image analy...
Article
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Alteration of pancreatic beta-cell survival and Preproinsulin gene expression by prolonged hyperglycemia may result from increased c-MYC expression. However, it is unclear whether c-MYC effects on beta-cell function are compatible with its proposed role in glucotoxicity. We therefore tested the effects of short-term c-MYC activation on key beta-cel...
Article
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Several studies have shown that the adult pancreas possesses a limited potential for beta-cell regeneration upon tissue injury. One of the difficulties in studying beta-cell regeneration has been the lack of a robust, synchronized animal model system that would allow controlled regulation of beta-cell loss and subsequent proliferation in adult panc...
Article
Introduction Il a été suggéré que l’augmentation d’expression du facteur de transcription c-MYC joue un rôle dans l’apoptose et le dysfonctionnement des cellules β provoquées par l’hyperglycémie chronique. Dans cette étude, nous avons comparé les effets d’une activation de c-MYC à ceux induits par des concentrations élevées de glucose sur la survie...
Article
?-cell failure, encompassing a range of aberrant cellular processes from dysfunction to death, has long been recognised as the central defect in Type 1 Diabetes Mellitus (T1DM), but is now also accepted as a major factor in essentially all other types of diabetes, notably the “epidemic” variant, Type 2 Diabetes (T2DM). However, the mechanisms invol...
Chapter
Deregulated expression of c-Myc is present in most, if not all, human cancers and is associated with a poor prognosis. The c-Myc proto-oncogene is essential for both cellular growth and proliferation, but paradoxically may also promote cell death. The study of this “dual potential” of c-Myc over the past two decades has provided a paradigm for expl...
Article
The c-Myc oncoprotein is a master regulator of genes involved in diverse cellular processes. Situated upstream of signalling pathways regulating cellular replication/growth as well as apoptosis/growth arrest, c-Myc may help integrate processes determining cell numbers and tissue size in physiology and disease. In cancer, this 'dual potential' allow...
Article
Full-text available
Reduced β-cell numbers and function (β-cell failure) contribute to essentially all forms of diabetes, and must be corrected if established disease is to be cured. Current therapies have been shown not to prevent β-cell failure and the availability of insulin-secreting cells for replacement-based therapies is severely restricted. Researchers have re...
Article
The hair follicle continually undergoes dynamic remodelling in a cyclical manner involving tightly coordinated patterns of cell proliferation, differentiation and apoptosis. The oncoprotein c-Myc is a key regulator of these events in epidermal keratinocytes, but its importance in the hair growth cycle has not previously been determined. To determin...
Article
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Tumour regression observed in many conditional mouse models following oncogene inactivation provides the impetus to develop, and a platform to preclinically evaluate, novel therapeutics to inactivate specific oncogenes. Inactivating single oncogenes, such as c-Myc, can reverse even advanced tumours. Intriguingly, transient c-Myc inactivation proved...
Article
During normal tissue homeostasis apoptotic cells (AC) are rapidly recognised and engulfed by neighbouring cells or macrophages (Mphi), thus preventing an inflammatory response. Conversely, in chronically inflamed tissues, including the atherosclerotic artery and rheumatoid joint, removal of AC is defective despite the co-localisation of seemingly a...
Article
The c-MYC proto-oncogene is essential for cellular proliferation but, paradoxically, may also promote cell death. Deregulated expression of c-MYC is present in most, if not all, human cancers, and is associated with a poor prognosis. However, given that human tumours at diagnosis generally carry multiple genetic lesions that have accumulated during...
Article
The proto-oncogene c-MYC is implicated in various physiological processes-cell growth, proliferation, loss of differentiation, and cell death (apoptosis). Oncogenic c-MYC implies constitutive or deregulated expression of c-MYC and is associated with many human cancers often with poor prognosis. Recently, c-MYC has been implicated in the loss and dy...
Article
Deregulated expression of c-MYC occurs in a broad range of human cancers and is often associated with poor prognosis, indicating a key role for this oncogene in tumour progression. However, as established human tumours often bear multiple genetic lesions, it is difficult to determine whether c-MYC is instrumental in the initiation/progression of th...
Article
To explore the role of c-Myc in carcinogenesis, we have developed a reversible transgenic model of pancreatic beta cell oncogenesis using a switchable form of the c-Myc protein. Activation of c-Myc in adult, mature beta cells induces uniform beta cell proliferation but is accompanied by overwhelming apoptosis that rapidly erodes beta cell mass. Thu...
Article
Full-text available
Pancreatic islet neoplasms are rare endocrine tumours. The most common type is of beta-cell origin and is known as insulinoma, which can be either benign or malignant. The majority of insulinomas arise sporadically, but a small proportion develop as part of the hereditary multiple endocrine neoplasia type 1 (MEN1) syndrome. As for many human tumour...
Article
The protein products of many dominant oncogenes are capable of inducing both cell proliferation and apoptosis. Recent experiments employing transgenic mice that express an ectopically regulatable myc gene or protein have begun to elucidate the role of the balance between proliferation and apoptosis in Myc-induced carcinogenesis. An outstanding feat...
Article
The protooncogene c-myc regulates cell growth, differentiation, and apoptosis, and its aberrant expression is frequently observed in human cancer. However, the consequences of activating c-Myc in an adult tissue, in which these cellular processes are part of normal homeostasis, remain unknown. In order to achieve this, we have targeted expression o...
Article
The protooncogene c-myc regulates cell growth, differentiation, and apoptosis, and its aberrant expression is frequently observed in human cancer. However, the consequences of activating c-Myc in an adult tissue, in which these cellular processes are part of normal homeostasis, remain unknown. In order to achieve this, we have targeted expression o...
Article
The ability to express cloned genes in mammalian cells has proved invaluable in the study of gene expression and function and in clinical applications for the correction of functional gene loss by gene therapy. Despite the wide use of DNA-mediated transfection of genes into eukaryotic cells, viruses possess several advantages for the transfer and e...
Article
Apoptosis of mammalian cell is under the control of a wide range of intracellular and extracellular factors-amongst them proteases, protein kinases, cytokines and the protein products of oncogenes and tumour suppressor genes. The c-myc proto-oncogene encodes an essential component of the cell's proliferative machinery and its deregulated expression...

Citations

... It outperformed state-of-the-art existing studies as shown in Table 6. Jaccard index and F1 score of the model are compared with U-Net [54], UNetþþ [55], DIST [33], MicroNet [56], ASPP Unet [40], SCPP-Net [57], Nuclei-SegNet [39], DenseRes-Unet [15], and DAN-NucNet [18]. The DAN-NucNet [18] is the second high performing model which has 0.84 F1 score and 0.74 Jaccard index. ...
... Xu et al. [23] proposed a multi-channel deep learning architecture in which three separate deep learning models were used to perform colon gland segmentation task and combined the results of different channels through a fusion network. Raza et al. [24] proposed the MIMO-Net, which has multiple-input and multiple-output for instance segmentation of colon glands. Furthermore, Yang et al. [25] proposed a deep active learning framework for the instance segmentation task using limited gland labels. ...
... The different performance of our network with different designs on NH-haze2023 dataset. Bolded indicates the best performanceSingle input Multi-scale inputMulti-scale output[44] Single-scale output Normal resblock[45] Res FFT-conv[46] Ours FLBlock ...
... Although the precise means by which DHA promotes these phenotypes remains to be determined, it appears to destabilize Myc protein by promoting its ubiquitin-dependent proteasomal degradation [28,45]. Because many tumors have been proposed to be dependent upon or "addicted" to high-level Myc expression [46,47], its loss may selectively impair their survival. ...
... A 2014 systematic review (Walker et al., 2014) examining the treatment of depression in cancer patients only identified 7 publications that met the inclusion criteria. Two of the studies examined the effect of pharmacologic therapies (Pezzella et al., 2001;Costa et al., 1985) and 1 explored pharmacologic versus psychologic treatment effects (Veitenhansl et al., 2004). Recently, the relationship between depression and inflammation was explored in cancer patients treated for depression. ...
... The total mass of β-cells changes over time: it continues to do so during adult life and it has become apparent during the past decade that the pathogenesis of both type 1 and type 2 diabetes involves failure to maintain an appropriate β-cell mass (Bonner- Weir, 2000;De León et al., 2003;Lee et al., 2006;Steil et al., 2001). The total mass is the combined result of three processes: proliferation (cell division), apoptosis (programmed cell death), and neogenesis (regeneration from a pool of rapidly dividing cells, which themselves derive from pluripotent stem cells, or possibly de-differentiated β-cells, or alternatively trans-differentiated pancreatic cells); these processes are influenced by the levels of both glucose and insulin (Beith et al., 1998;Bouwens and Rooman, 2005;Dor et al., 2004;Efanova et al., 1998;Johnson and Alejandro, 2008;Lipsett and Finegood, 2002;Rooman et al., 2002;Young et al., 2008). As a result, there is an interplay between the fast, ultradian fluctuations of glucose and insulin and the slower (>days) changes in β-cell mass. ...
... Additionally, to explore CKE effect on c-MYC expression in DMBA/TPA induced mice, we performed IHC and qPCR analysis of Skin and tumor tissue obtained from all grouped mice. According to reports, the development of SSC is influenced by the activation of protooncogenes like c-MYC overexpression and/or the inactivation of tumor suppressor genes like p53 mutation (34,(40)(41)(42)(43). c-MYC was one of the first oncogenes to be identified as being involved in the development of cancer. ...
... Blood glucose levels increased from Day 2, peaking at >25 mmol/l on Day 7. Blood glucose levels fell rapidly following Myc deactivation and were largely normalised at 3 weeks, by which time glucose levels were identical to those of wild-type littermates. Glucose levels remained slightly above mean pre-treatment levels, which, as previously shown, are generally slightly lower than average for wild-type mice [33]. Importantly, transgenic and wild-type mice had an essentially normal response to glucose tolerance tests on Days 26 and 57 (3 weeks after c- Myc was 'switched off') (ESMFig. ...
... IGF-II, a known mitogen, is structurally related to insulin and may contribute to expansion of the β-cell population in times of need (e.g. during diabetes, obesity or pregnancy) [6][7][8][9][10]. The bioactivities of insulin, IGF-II and IGF-I are mediated via interaction with one or more members of a closely-related family of receptors; the insulin receptor (IR), which exists in two isoforms (A and B), and the IGF type-1 receptor (IGF1R). ...
... Human and mouse C-MYC is expressed ubiquitously during development in growing tissues, and in adult tissue compartments possessing high proliferative capacity (e.g. skin epidermis and gut), however it is undetected in cells that have exited the cell cycle (Semsei et al., 1989;Mattsson et al., 2006). The expression of human and mouse NANOG was also demonstrated in a variety of somatic cells (Hart et al., 2004;Ambady et al., 2010). ...