Biased signalling at the IGF-1R : pitfalls and potential of the GRK/beta-arrestin system in cancer therapeutics

Embedded into the boundary between the living machinery and the external space, plasma membrane receptors allow cells to perceive their environment and elicit appropriate responses. Two of the largest classes of receptors are the G protein-coupled receptors (GPCRs) and receptor tyrosine kinases (RTKs). Distinct in their structural and functional characteristics, each lend themselves to important cellular operations. While crosstalk between members of either family is a general phenomenon, a growing body of evidence suggests there may be a more direct overlap. This thesis explores the insulin-like growth factor type 1 receptor (IGF-1R), as an intermediate between these two receptor families. Supporting growth and survival in many human cancers, the IGF-1R has long been considered an attractive therapeutic target. Despite the pre-clinical appeal and intense pharmaceutical development, disappointing clinical trials suggest that its potential has not been fulfilled. This thesis examines the true complexity of this receptor system, with particular focus on its use of GPCR components and how they contribute to the paradigm of biased signalling. Study I categorizes the therapeutic relevance of biased signalling at the IGF-1R. Our results identify small molecule Nutlin-3 as strategy that synergizes with MEK inhibition, by cotargeting the p53 and IGF-1R, without biased signal activation. Study II set out to define the role of the β-arrestin 2 isoform at the IGF-1R, and in doing so identifies the mechanism controlling a balanced versus biased receptor conformation. The β-arrestin isoforms antagonize each other’s function at the IGF-1R, imposing regulation on the receptor expression, signalling and crosstalk to p53. The position of β-arrestins, between an important mitogenic pathway and perhaps the ultimate tumour suppressor pathway, reveals potential for therapeutic gain. Study III develops strategies for targeting β-arrestin/GRK-biased agonism at the IGF-1R for cancer treatment, with focus on clinical applicability. This work provides the proof of concept for cross-targeting the IGF-1R through GRK 2 inhibition, and suggests clinical feasibility of such an approach by repurposing the widely used drug paroxetine. Acknowledging the clinical importance of biased signalling at the IGF-1R, Study IV aims to explore the utility of microRNAs as biomarkers to quantify signalling bias downstream of IGF-1R. MicroRNA array and IGF-1R mutation analysis identifies miR-106a as a candidate that can specify a β-arrestin biased IGF-1R signal that could be developed for patient stratification in anti-IGF-1R trials. Altogether, our findings highlight the shortcomings of first line anti-IGF-1R strategies, and the overly simplistic models in use at the time. Armed with an appreciation of the true complexity, plasticity and interconnectivity of receptor systems, we have examined the therapeutic utility of the novel components GRK/β-arrestin, and identified targets that may hold potential in unlocking the true potential of anti-IGF-1R

Women in film 1986-2016: Has their representation improved or worsened?

Women in film have been consistently underrepresented over the years. The representation of women and minorities in media is incredibly important, as people need to see themselves reflected back in the stories they consume. Young girls should be able to see well-written, complicated characters that are able to stand on their own without a man or anyone else. It is possible for the lack of representation to negatively affect the attitude towards women in society. This dissertation examines the 31 top-grossing films over a 30-year period, between 1986 and 2016. This is to analyse whether the representation of women in film has improved in the types of roles and increased in numbers, or worsened in the same respect. I conducted quantitative and qualitative content analysis on the 31 films and looked at the characters and how they are shown in each of the films. The analysis showed that there is a pattern of roles that women play which haven’t really changed in 30 years. And it also showed that while the numbers of women have indeed increased over the years and the roles have slightly improved, there is still a lot of work to be done on the stereotypical and similar roles that women are often reduced to

Learning to collaborate : lessons from the design studio

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1997.Includes bibliographical references (p. 103-105).This thesis examines the dynamics of collaboration within the architectural design studio by focusing on the basic elements of group interaction (Commitment, Conflict, Communication, the Collaborative Process and the Role of the Critic), as they apply to both the process and products of collaborative design. The theoretical discussion is supported with data collected from observations of two 'collaborative' studios organized by the School of Architecture and Planning at MIT. Effective collaborative skills are considered to be an important issue for practicing architects, yet these skills are often overlooked in the studio. This thesis proposes an educational pedagogy that balances the teaching of collaborative skills with the teaching of traditional design skills.by Jane M. Crudden.M.S

The Effect of Nb/Ti Ratio on Hardness in High-Strength Ni-Based Superalloys

The age-hardening behaviour and microstructure development of high strength Ni-based superalloys ABD-D2, D4, and D6 with varying Nb/Ti ratios have been studied. The studied alloys have large volume fractions and multimodal size distributions of the γ′ precipitates, making them sensitive to cooling conditions following solution heat treatment. Differential scanning calorimetry was conducted with a thermal cycle that replicated a processing heat treatment. The hardness of these alloys was subsequently evaluated by nanoindentation. The Nb/Ti ratio was not observed to influence the size and distribution of primary and secondary γ′ precipitates; however, the difference in those of tertiary γ′ and precipitate morphology were observed. The nanoindentation hardness for all alloys reduces once they have been solution-heat-treated. The alloys exhibited specific peak hardness. The alloy with the greatest Nb content was found to have the best increase in hardness among the alloys studied due to its large tertiary γ′ precipitate

Highly ordered N-heterocyclic carbene monolayers on Cu(111)

EA and FG acknowledge funding from EPSRC grants (EA: EP/R512199/1; FG: EP/S027270/1). We thank the EaStCHEM for computational support via the EaStCHEM Research Computing facility. CMC thanks the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Canada Foundation for Innovation (CFI) for funding of the work from her lab described in this article. AJV acknowledges NSERC for a Vanier scholarship and the Walter C. Sumner foundation for additional financial support. IS acknowledges Queen’s University for the RT Mohan Scholarship and the Ontario government for an Ontario Graduate Scholarship.The benzannulated N-heterocyclic carbene, 1,3-dibenzylbenzimidazolylidene (NHCDBZ) forms large, highly ordered domains when adsorbed on Cu(111) under ultrahigh vacuum conditions. A combination of scanning tunnelling microscopy (STM), high resolution electron energy loss spectroscopy (HREELS) and density functional theory (DFT) calculations reveals that the overlayer consists of vertical benzannulated NHC moieties coordinating to Cu adatoms. Long range order results from the placement of the two benzyl substituents on opposite sides of the benzimidazole moiety, with their aromatic rings approximately parallel to the surface. The organization of three surface-bound benzyl substituents from three different NHCs into a triangular array controls the formation of a highly ordered Kagome-like surface lattice. By comparison with earlier studies of NHCs on Cu(111), we show that the binding geometry and self-assembly of NHCDBZ are influenced by intermolecular and adsorbate-substrate interactions and facilitated by the flexibility of the methylene linkage between the N-heterocycle and the aromatic wingtip substituents.Publisher PDFPeer reviewe

Chiral carbene–borane adducts: precursors for borenium catalysts for asymmetric FLP hydrogenations

The carbene derived from (1R,3S)-camphoric acid was used to prepare the borane adduct with Piers’ borane 7. Subsequent hydride abstraction gave the borenium cation 8. Adducts with 9-BBN and the corresponding (1R,3S)-camphoric acid-derived carbene bearing increasingly sterically demanding N-substituents (R = Me 9, Et 10, i-Pr 11) and the corresponding borenium cations 12–14 were also prepared. These cations were not active as catalysts in hydrogenation, although 9–11 were shown to undergo carbene ring expansion reactions at 50 °C to give species 15–17. The IBOX-carbene precursors 18 and 19 derived from amino alcohols (S)-valinol and (S)-tert-leucinol (R = i-Pr, t-Bu) were used to prepare borane adducts 20–23. Reaction of the carbenes 1,3-dimethylimidazol-2-ylidene (IMe), 1,3-di-iso-propylimidazol-2-ylidene (IPr) 1-benzyl-3-methylimidazol-2-ylidene (IBnMe), 1-methyl-3-phenylimidazol-2-ylidene (IPhMe) and 1-tert-butyl-3-methylimidazol-2-ylidene (ItBuMe) with diisopinocampheylborane (Ipc2BH) gave chiral adducts: (IMe)(Ipc2BH) 24, (IPr)(Ipc2BH) 25, (IBnMe)(Ipc2BH) 26, (IPhMe)(Ipc2BH) 27, and (ItBuMe)(Ipc2BH) 28. Triazolylidene-type adducts including the (10)-phenyl-9-borabicyclo [3.3.2]decane adduct of 1,3,4-triphenyl-1H-1,2,3-triazolium, rac-29 and the 9-BBN derivative of (S)-2-amino-2′-methoxy-1,1′-binaphthalene-1,2,3-triazolium 34a/b were also prepared. In catalytic studies of these systems, while several species were competent catalysts for imine reduction, in general, low enantioselectivities, ranging from 1–20% ee, were obtained. The implications for chiral borenium cation catalyst design are considered