Publications by authors named "Rolfe D"

The Epidermal Growth Factor Receptor (EGFR) is frequently found to be mutated in non-small cell lung cancer. Oncogenic EGFR has been successfully targeted by tyrosine kinase inhibitors, but acquired drug resistance eventually overcomes the efficacy of these treatments. Attempts to surmount this therapeutic challenge are hindered by a poor understanding of how and why cancer mutations specifically amplify ligand-independent EGFR auto-phosphorylation signals to enhance cell survival and how this amplification is related to ligand-dependent cell proliferation.

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Fibronectin Leucine-rich Repeat Transmembrane (FLRT 1-3) proteins are a family of broadly expressed single-spanning transmembrane receptors that play key roles in development. Their extracellular domains mediate homotypic cell-cell adhesion and heterotypic protein interactions with other receptors to regulate cell adhesion and guidance. These in trans FLRT interactions determine the formation of signaling complexes of varying complexity and function.

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Cancer is a leading cause of death among Inuit. A legacy of colonialism, residential schools, and systemic racism has eroded trust among Inuit and many do not receive culturally safe care. This study aimed to explore the meaning of culturally safe cancer survivorship care for Inuit, and barriers and facilitators to receiving it in an urban setting in Ontario Canada.

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Street nurses who serve people experiencing homelessness and substance abuse are at risk of vicarious trauma and long-term mental health challenges. These risks have increased during the COVID-19 pandemic due to a concomitant spike in opioid overdoses and deaths in Canada, fewer available support services and worsening social challenges. This article describes innovative interdisciplinary and participatory research currently being undertaken to develop and evaluate a multifaceted support program to promote the holistic well-being of street nurses and their front-line colleagues.

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Article Synopsis
  • - Pseudokinases, despite being catalytically inactive, play crucial roles in cellular signaling as allosteric regulators and are linked to various human diseases, making them key targets for therapy.
  • - The study explores ways to create small molecules that can lock pseudokinases like HER3 in an inactive conformation to inhibit their interactions, particularly in the context of cancer progression.
  • - Using a thermal shift assay screening over 100,000 compounds, the research identified a compound, AC3573, that specifically binds to HER3, preventing the formation of a harmful HER2-HER3 complex and blocking signaling pathways in cells.
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Our mechanistic understanding of cell function depends on imaging biological processes in cells with molecular resolution. Super-resolution fluorescence microscopy plays a crucial role by reporting cellular ultrastructure with 20-30 nm resolution. However, this resolution is insufficient to image macro-molecular machinery at work.

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The dependence on model-fitting to evaluate particle trajectories makes it difficult for single particle tracking (SPT) to resolve the heterogeneous molecular motions typical of cells. We present here a global spatiotemporal sampler for SPT solutions using a Metropolis-Hastings algorithm. The sampler does not find just the most likely solution but also assesses its likelihood and presents alternative solutions.

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: Rates of electronic cigarettes (e-cigarette) use (vaping) have increased among college students over the past decade. : The current study sought to provide an in-depth examination of college students' beliefs about and attitudes toward cigarettes and e-cigarettes that may influence support/non-support of tobacco-free policies on college campuses and within their communities. : Between August and December 2015, five focus groups ( = 22) were conducted at a large Southern University.

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Plant plasma-membrane (PM) proteins are involved in several vital processes, such as detection of pathogens, solute transport, and cellular signaling. For these proteins to function effectively there needs to be structure within the PM allowing, for example, proteins in the same signaling cascade to be spatially organized. Here we demonstrate that several proteins with divergent functions are located in clusters of differing size in the membrane using subdiffraction-limited Airyscan confocal microscopy.

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Super-resolution fluorescence microscopy plays a crucial role in our understanding of cell structure and function by reporting cellular ultrastructure with 20-30 nm resolution. However, this resolution is insufficient to image macro-molecular machinery at work. A path to improve resolution is to image under cryogenic conditions.

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Plain English Summary: There have been many attempts to improve how healthcare services are developed and delivered. Despite this, we know that there are many gaps and differences in practice and that these can lead to poor patient outcomes. In addition, there are also concerns that research is being undertaken that does not reflects the realities or needs of those using healthcare services, and that the use of research findings in practice is slow.

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Plain English Summary: Patient engagement (or patient and public involvement) in health research is becoming a requirement for many health research funders, yet many researchers have little or no experience in engaging patients as partners as opposed to research subjects. Additionally, many patients have no experience providing input on the research design or acting as a decision-making partner on a research team. Several potential risks exist when patient engagement is done poorly, despite best intentions.

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Our current understanding of epidermal growth factor receptor (EGFR) autoinhibition is based on X-ray structural data of monomer and dimer receptor fragments and does not explain how mutations achieve ligand-independent phosphorylation. Using a repertoire of imaging technologies and simulations we reveal an extracellular head-to-head interaction through which ligand-free receptor polymer chains of various lengths assemble. The architecture of the head-to-head interaction prevents kinase-mediated dimerisation.

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Background: Venous leg ulcers (VLUs) are the most common cause of leg ulceration, affecting 1 in 100 adults. VLUs may take many months to heal (25% fail to heal). Estimated prevalence is between 1% and 3% of the elderly population.

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HIV treatment in Canada has rapidly progressed with the advent of new drug therapies and approaches to care. With this evolution, there is increasing interest in Canada in understanding the current delivery of HIV care, specifically where care is delivered, how, and by whom, to inform the design of care models required to meet the evolving needs of the population. We conducted a cross-sectional survey of Canadian care settings identified as delivering HIV care between June 2015 and January 2016.

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Background: Cerebral small vessel disease is a common cause of vascular cognitive impairment in older people, with no licensed treatment. Cerebral blood flow is reduced in small vessel disease. Tadalafil is a widely prescribed phosphodiesterase-5 inhibitor that increases blood flow in other vascular territories.

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Epidermal growth factor receptor (EGFR) signalling is activated by ligand-induced receptor dimerization. Notably, ligand binding also induces EGFR oligomerization, but the structures and functions of the oligomers are poorly understood. Here, we use fluorophore localization imaging with photobleaching to probe the structure of EGFR oligomers.

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Optical aberrations degrade image quality in fluorescence microscopy, including for single-molecule based techniques. These depend on post-processing to localize individual molecules in an image series. Using simulated data, we show the impact of optical aberrations on localization success, accuracy and precision.

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Introduction: This paper explores whether, and under what circumstances, a biosimilar approved in the United States under the Biologics Price Competition and Innovation Act (hereafter 'BPCIA') can be patented. The possibility that a biosimilar product could have meaningful patent protection arises from specific requirements for biosimilarity under the BPCIA, which account for the fact that manufacturing processes of biologics are inherently imprecise. The requirements for biosimilar approval may provide sufficient leeway to a biosimilar applicant to patent structural or formulation differences that provide non-clinical but business-relevant advantages over the reference molecule, such as improved shelf-life or ease of manufacture, without compromising clinical biosimilarity.

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Background: Venous leg ulcers (VLUs) are the commonest cause of leg ulceration, affecting 1 in 100 adults. There is a significant health burden associated with VLUs - it is estimated that the cost of treatment for 1 ulcer is up to £1300 per year in the NHS. The mainstay of treatment is with graduated compression bandaging; however, treatment is often prolonged and up to one quarter of venous leg ulcers do not heal despite standard care.

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Responsible Research and Innovation (RRI) provides a framework for judging the ethical qualities of innovation processes, however guidance for researchers on how to implement such practices is limited. Exploring RRI in the context of nanotechnology, this paper examines how the dispersed and interdisciplinary nature of the nanotechnology field somewhat hampers the abilities of individual researchers to control the innovation process. The ad-hoc nature of the field of nanotechnology, with its fluid boundaries and elusive membership, has thus far failed to establish a strong collective agent, such as a professional organization, through which researchers could collectively steer technological development in light of social and environmental needs.

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The challenge of determining the architecture and geometry of oligomers of the epidermal growth factor receptor (EGFR) on the cell surface has been approached using a variety of biochemical and biophysical methods. This review is intended to provide a narrative of how key concepts in the field of EGFR research have evolved over the years, from the origins of the prevalent EGFR signalling dimer hypothesis through to the development and implementation of methods that are now challenging the conventional view. The synergy between X-ray crystallography and cellular fluorescence microscopy has become particularly important, precisely because the results from these two methods diverged and highlighted the complexity of the challenge.

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There is a limited range of methods available to characterize macromolecular organization in cells on length scales from 5-50 nm. We review methods currently available and show the latest results from a new single-molecule localization-based method, fluorophore localization imaging with photobleaching (FLImP), using the epidermal growth factor (EGF) receptor (EGFR) as an example system. Our measurements show that FLImP is capable of achieving spatial resolution in the order of 6 nm.

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Although considerable progress has been made in imaging distances in cells below the diffraction limit using FRET and super-resolution microscopy, methods for determining the separation of macromolecules in the 10-50 nm range have been elusive. We have developed fluorophore localisation imaging with photobleaching (FLImP), based on the quantised bleaching of individual protein-bound dye molecules, to quantitate the molecular separations in oligomers and nanoscale clusters. We demonstrate the benefits of using our method in studying the nanometric organisation of the epidermal growth factor receptor in cells.

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Article Synopsis
  • Dimerisation, oligomerisation, and clustering of receptor molecules are crucial for signaling control, but studying these processes has been challenging due to a lack of suitable methods.
  • The new method called "fluorophore localisation imaging with photobleaching" (FLImP) allows researchers to measure the distance between two fluorophores with a resolution of 7 nm or better, enhancing the understanding of these processes.
  • Recent FLImP data reveals that the intracellular domain of the Epidermal Growth Factor Receptor is not needed for it to form ordered inactive oligomers in the plasma membrane under basal conditions.
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