The Role of Chemokine Receptors CCR6 and CCR7 in the Initiation and Progression of Breast Cancer

Breast cancer is one of the most common causes of cancer-related death in women world-wide. Despite many advances in medical research, incidence and mortality rates still remain high. In the last decade, evidence has emerged that links components of the immune system, including various signalling mediators and cell subsets, with regulation and promotion of breast cancer. Among others, the chemokine superfamily has been heavily implicated in the pathobiology of breast cancer due to their ability to induce cellular migration, proliferation and recruitment of supporting cells to the tumour microenvironment upon binding of cognate chemokine receptors. However, the underlying mechanisms and specific details governing the function of chemokines and their receptors in regulating breast cancer development and progression are largely unknown. This study systematically examined the roles of two chemokine receptors, CCR7 and CCR6, in breast cancer initiation and progression. These receptors had previously been shown to induce cellular proliferation and migration of breast cancer cell lines upon stimulation with chemokine ligands and had been implicated in regulation of other malignancies, but in vivo evidence for their roles had not been shown to date. Using the MMTV-PyMT transgenic mouse model for breast cancer, it was found that deletion of CCR7 significantly delayed mammary tumour onset and reduced both the number of primary tumours and extent of distal metastasis to the lungs. It was further found that CCR7 exerted its tumour-promoting function by maintaining populations of stem-like cancer cells. Stimulation of CCR7 in stem cell-enriched cultures induced self-renewal and the loss of this receptor resulted in a significant decrease in tumour-propagating ability of the cells. Furthermore, pharmacological blockade of CCR7 reduced proportions and activity of stem cell-like pools, indicating that this receptor can potentially be targeted therapeutically to eliminate quiescent cancer stem cells. Deletion of CCR6 in the MMTV-PyMT model also significantly delayed tumour onset, reduced the extent of epithelial hyperplasia, and resulted in a decreased incidence of mammary tumours. However, no evidence was found of a role for CCR6 in mammary epithelium, or in maintenance of the cell lineage hierarchy. Upon further investigation, it was discovered that CCR6 was involved in the recruitment of tumour-promoting macrophages to the mammary tumour microenvironment. CCR6 was highly expressed on tumour-associated macrophages, and the loss of CCR6 significantly reduced the numbers of macrophages present in PyMT-driven mammary tumours. Taken together, cumulative data generated throughout the course of this project conclusively demonstrate that CCR7 and CCR6 both have important roles in the development and progression of breast cancer and may therefore have therapeutic utility in targeting both the transformed mammary epithelium and the supporting tumour microenvironment.Thesis (Ph.D.) -- University of Adelaide, School of Biological Sciences, 201

A Nonlethal Method to Examine Non-Apis Bees for Mark-Capture Research

Studies of bee movement and activities across a landscape are important for developing an understanding of their behavior and their ability to withstand environmental stress. Recent research has shown that proteins, such as egg albumin, are effective for mass-marking bees. However, current protein mass-marking techniques require sacrificing individual bees during the data collection process. A nonlethal sampling method for protein mark-capture research is sorely needed, particularly for vulnerable, sensitive, or economically valuable species. This study describes a nonlethal sampling method, in which three non-Apis bee species (Bombus bifarius Cresson [Hymenoptera: Apidae], Osmia lignaria Say [Hymenoptera: Megachilidae], and Megachile rotundata Fabricius [Hymenoptera: Megachilidae]) were tested for a unique protein marker by immersing them momentarily in saline buffer and releasing them. Results showed that an egg albumin-specific enzyme-linked immunosorbent assay was 100% effective at detecting the protein on bees that were sampled nonlethally. Furthermore, this sampling method did not have an impact on bee survivorship, suggesting that immersing bees in buffer is a reliable and valid surrogate to traditional, destructive sampling methods for mark-capture bee studies

Neuronal guidance molecule netrin-1 attenuates inflammatory cell trafficking during acute experimental colitis

Background: Inflammatory bowel diseases, encompassing Crohn’s disease and ulcerative colitis, are characterised by persistent leucocyte tissue infiltration leading to perpetuation of an inappropriate inflammatory cascade. The neuronal guidance molecule netrin-1 has recently been implicated in the orchestration of leucocyte trafficking during acute inflammation. We therefore hypothesised that netrin-1 could modulate leucocyte infiltration and disease activity in a model of inflammatory bowel disease. Design: DSS-colitis was performed in mice with partial genetic netrin-1 deficiency (Ntn-1+/- mice) or wild-type mice treated with exogenous netrin-1 via osmotic pump to examine the role of endogenous and therapeutically administered netrin-1. These studies were supported by in vitro models of transepithelial migration and intestinal epithelial barrier function. Results: Consistent with our hypothesis, we observed induction of netrin-1 during intestinal inflammation in vitro or in mice exposed to experimental colitis. Moreover, mice with partial netrin-1 deficiency demonstrated an exacerbated course of DSS-colitis compared to littermate controls, with enhanced weight loss and colonic shortening. Conversely, mice treated with exogenous mouse netrin-1 experienced attenuated disease severity. Importantly, permeability studies and quantitative assessment of apoptosis reveal that netrin-1 signalling events do not alter mucosal permeability or intestinal epithelial cell apoptosis. In vivo studies of leucocyte transmigration demonstrate suppression of neutrophil trafficking as a key function mediated by endogenous or exogenously administered netrin-1. Finally, genetic studies implicate the A2B adenosine receptor in netrin-1-mediated protection during DSS-colitis. Conclusions: The present study identifies a previously unrecognised role for netrin-1 in attenuating experimental colitis through limitation of neutrophil trafficking

Prevalence and predictive value of ICD-11 post-traumatic stress disorder and Complex PTSD diagnoses in children and adolescents exposed to a single-event trauma.

BACKGROUND: The 11th edition of the International Classification of Diseases (ICD-11) made a number of significant changes to the diagnostic criteria for post-traumatic stress disorder (PTSD). We sought to determine the prevalence and 3-month predictive values of the new ICD-11 PTSD criteria relative to ICD-10 PTSD, in children and adolescents following a single traumatic event. ICD-11 also introduced a diagnosis of Complex PTSD (CPTSD), proposed to typically result from prolonged, chronic exposure to traumatic experiences, although the CPTSD diagnostic criteria do not require a repeated experience of trauma. We therefore explored whether children and adolescents demonstrate ICD-11 CPTSD features following exposure to a single-incident trauma. METHOD: Data were analysed from a prospective cohort study of youth aged 8-17 years who had attended an emergency department following a single trauma. Assessments of PTSD, CPTSD, depressive and anxiety symptoms were performed at two to four weeks (n = 226) and nine weeks (n = 208) post-trauma, allowing us to calculate and compare the prevalence and predictive value of ICD-10 and ICD-11 PTSD criteria, along with CPTSD. Predictive abilities of different diagnostic thresholds were undertaken using positive/negative predictive values, sensitivity/specificity statistics and logistic regressions. RESULTS: At Week 9, 15 participants (7%) were identified as experiencing ICD-11 PTSD, compared to 23 (11%) experiencing ICD-10 PTSD. There was no significant difference in comorbidity rates between ICD-10 and ICD-11 PTSD diagnoses. Ninety per cent of participants with ICD-11 PTSD also met criteria for at least one CPTSD feature. Five participants met full CPTSD criteria. CONCLUSIONS: Reduced prevalence of PTSD associated with the use of ICD-11 criteria is likely to reduce identification of PTSD relative to using ICD-10 criteria but not relative to DSM-4 and DSM-5 criteria. Diagnosis of CPTSD is likely to be infrequent following single-incident trauma

Controlled density-downramp injection in a beam-driven plasma wakefield accelerator

This paper describes the utilization of beam-driven plasma wakefield acceleration to implement a high-quality plasma cathode via density-downramp injection in a short injector stage at the FLASHForward facility at DESY. Electron beams with charge of up to 105 pC and energy spread of a few percent were accelerated by a tunable effective accelerating field of up to 2.7 GV/m. The plasma cathode was operated drift-free with very high injection efficiency. Sources of jitter, the emittance and divergence of the resulting beam were investigated and modeled, as were strategies for performance improvements that would further increase the wide-ranging applications for a plasma cathode with the demonstrated operational stabilityComment: 11 pages, 9 figure

CropPol: a dynamic, open and global database on crop pollination

Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions. Here, we present CropPol, a dynamic, open and global database on crop pollination. It contains measurements recorded from 202 crop studies, covering 3,394 field observations, 2,552 yield measurements (i.e. berry weight, number of fruits and kg per hectare, among others), and 47,752 insect records from 48 commercial crops distributed around the globe. CropPol comprises 32 of the 87 leading global crops and commodities that are pollinator dependent. Malus domestica is the most represented crop (32 studies), followed by Brassica napus (22 studies), Vaccinium corymbosum (13 studies), and Citrullus lanatus (12 studies). The most abundant pollinator guilds recorded are honey bees (34.22% counts), bumblebees (19.19%), flies other than Syrphidae and Bombyliidae (13.18%), other wild bees (13.13%), beetles (10.97%), Syrphidae (4.87%), and Bombyliidae (0.05%). Locations comprise 34 countries distributed among Europe (76 studies), Northern America (60), Latin America and the Caribbean (29), Asia (20), Oceania (10), and Africa (7). Sampling spans three decades and is concentrated on 2001-05 (21 studies), 2006-10 (40), 2011-15 (88), and 2016-20 (50). This is the most comprehensive open global data set on measurements of crop flower visitors, crop pollinators and pollination to date, and we encourage researchers to add more datasets to this database in the future. This data set is released for non-commercial use only. Credits should be given to this paper (i.e., proper citation), and the products generated with this database should be shared under the same license terms (CC BY-NC-SA). This article is protected by copyright. All rights reserved