Regulation and Targeting of Fyn in Human Cutaneous Squamous Cell Carcinoma

Fyn, a member of the Src family kinases, is an oncogene in murine epidermis and is associated with cell-cell adhesion turnover and migration. Introduction of active H-Ras(G12V) into the HaCaT human keratinocyte cell line resulted in upregulation of FYN mRNA (200-fold) and protein, but did not increase the expression of other SFKs. We identified two nucleotides 74 bases upstream of the human FYN gene transcription start site as necessary for FYN upregulation in HaCaT-Ras cells. Further studies identified Lef-1 as the transcription factor most likely binding to this site and mediating FYN upregulation. Transduction of active Ras or Fyn was sufficient to induce an epithelial-to-mesenchymal transition in HaCaT cells. Introduction of Ras or Fyn also resulted in upregulation of the EMT master regulator, TWIST1, demonstrating a potential mechanism driving the transition to a mesenchymal phenotype. Fyn inhibition using siRNA or the clinical SFK inhibitor Dasatinib increased cell-cell adhesion in HaCaT-Ras cells over 6-fold (p\u3c0.001) through a rapid (5-60 min.) increase in the cortical F-actin cytoskeleton. Treatment of the HaCaT-Fyn cells with Dasatinib also resulted in upregulation of F-actin. Induced F-actin colocalized with the adherens junction proteins α-catenin, β-catenin and p120catenin in HaCaT-Ras cells, suggesting that stable adherens junctions were mediating the increase in cell-cell adhesion. Additionally, Dasatinib treatment significantly inhibited cell migration (p\u3c0.001). Dasatinib-induced cell-cell adhesion could be blocked by Cytochalasin D, indicating that F-actin polymerization was a key initiator of cell-cell adhesion through the adherens junction. Conversely, inhibiting cell-cell adhesion with low Ca2+ media did not block Dasatinib-induced F-actin polymerization. Inhibition of the Rho effector kinase ROCK blocked Dasatinib-induced F-actin and cell-cell adhesion, implicating relief of Rho GTPase inhibition as a mechanism of Dasatinib-induced cell-cell adhesion. Finally, topical Dasatinib treatment immediately following UV exposure significantly reduced total tumor burden in the SKH1 mouse model of skin carcinogenesis (p\u3c0.05). Together these results identify the promotion of actin-based cell-cell adhesion as a newly described mechanism of action for Dasatinib and suggest that Fyn inhibition may be an effective therapeutic approach in treating SCC

B-Raf-Mutated Melanoma

Until fairly recently, treatment options for advanced melanoma have been relatively limited. Fortunately, the last decade has seen dramatic improvements in response rates and duration of overall survival after the introduction of checkpoint inhibitors and targeted therapies against mutations in the B-isoform of Raf (B-Raf) in metastatic or inoperable melanoma. This book chapter will discuss the role of wild type B-Raf in the cell, the changes induced by mutations in this protein, and current FDA approvals for targeted therapies against B-Raf, both as a monotherapy and in combination with MEK inhibitors. We will also summarize mechanisms of resistance against these targeted therapies as well as novel therapeutic regimens proposed to bypass resistance

Epidemiology and fitness effects of wood mouse herpesvirus in a natural host population

Rodent gammaherpesviruses have become important models for understanding human herpesvirus diseases. In particular, interactions between murid herpesvirus 4 and Mus musculus (a non-natural host species) have been extensively studied under controlled laboratory conditions. However, several fundamental aspects of murine gammaherpesvirus biology are not well understood, including how these viruses are transmitted from host to host, and their impacts on host fitness under natural conditions. Here, we investigate the epidemiology of a gammaherpesvirus in free-living wood mice (Apodemus sylvaticus) and bank voles (Myodes glareolus) in a 2-year longitudinal study. Wood mouse herpesvirus (WMHV) was the only herpesvirus detected and occurred frequently in wood mice and also less commonly in bank voles. Strikingly, WMHV infection probability was highest in reproductively active, heavy male mice. Infection risk also showed a repeatable seasonal pattern, peaking in spring and declining through the summer. We show that this seasonal decline can be at least partly attributed to reduced recapture of WMHV-infected adults. These results suggest that male reproductive behaviours could provide an important natural route of transmission for these viruses. They also suggest that gammaherpesvirus infection may have significant detrimental effects in wild hosts, questioning the view that these viruses have limited impacts in natural, co-evolved host species

Standardized parenteral nutrition for the transition phase in preterm infants: a bag that fits

The optimal composition of standardized parenteral nutrition (SPN) is not yet known, contributing to nutrient deficit accrual and growth failure, with the period of parenteral nutrition weaning, i.e., transition (TN) phase, being identified as particularly vulnerable. We created a comprehensive nutrition database, representative of the nutritional course of a diverse range of preterm infants (n = 59, birth weight ≤ 1500 g, gestation < 34 weeks) by collecting hourly macronutrient intake data as part of a prospective, observational study over 19 months. Using a nutrient modeling technique for the TN phase, various amino acid (AA) concentrations of SPN were tested within the database, whilst acknowledging the nutritional contribution from enteral feeds until target AA intakes were consistently achieved. From the modeling, the AA composition of SPN was determined at 3.5 g/100 mL, which was the maximum to avoid exceeding target intakes at any point in the TN phase. However, in order to consistently achieve target AA intakes, additional nutritional strategies were required, which included increasing the exclusion of enteral feeds in fluid and nutrient calculations from <20 mL/kg/day to <40 mL/kg/day, and earlier fortification of breastmilk at 80 mL/kg/day. This data-driven nutrient modeling process supported the development of an improved SPN regimen for our preterm population in the TN phase

A Protocol for a Rapid Realist Review of Literature Examining Co-Production in Youth Mental Health Services

An overview of internationally published literature on what works for co-production in youth mental health services is missing, despite a practice and policy context strongly recommending this approach. The proposed rapid realist review aims to develop a theory about how and why co-production methods in youth mental health services work (or do not work), for whom, in which contexts, and through what mechanisms. Relevant evidence will be synthesised to develop context–mechanism–outcome (CMO) configurations that can inform policy and practice. Stakeholders will be iteratively involved in the development of these theories (CMO configurations) by engaging an expert panel and youth advisory group. The review results will be reported according to the RAMESES guidelines and are intended to be published in an academic journal. Additionally, a plain English summary will be produced with the support of the youth advisory group