Mutant p53s (mutp53) increase cancer invasiveness by upregulating Rab-coupling protein (RCP) and diacylglycerol kinase-α (DGKα)-dependent endosomal recycling. Here we report that mutp53-expressing tumour cells produce exosomes that mediate intercellular transfer of mutp53’s invasive/migratory gain-of-function by increasing RCP-dependent integrin recycling in other tumour cells. This process depends on mutp53’s ability to control production of the sialomucin, podocalyxin, and activity of the Rab35 GTPase which interacts with podocalyxin to influence its sorting to exosomes. Exosomes from mutp53-expressing tumour cells also influence integrin trafficking in normal fibroblasts to promote deposition of a highly pro-invasive extracellular matrix (ECM), and quantitative second harmonic generation microscopy indicates that this ECM displays a characteristic orthogonal morphology. The lung ECM of mice possessing mutp53-driven pancreatic adenocarcinomas also displays increased orthogonal characteristics which precedes metastasis, indicating that mutp53 can influence the microenvironment in distant organs in a way that can support invasive growth.
AIM To determine the efficacy of web-based training on activity capacity and performance in children with unilateral cerebral palsy (CP).METHOD In a matched-pairs randomized waitlist controlled trial, independently ambulant children and adolescents with unilateral CP were allocated to receive 30 minutes of training (intervention) 6 days per week, or usual care (waitlist control) for 20 weeks. Activity capacity was assessed using maximal repetitions of functional strength tasks and 6-minute walk test (6MWT); performance using 4-day ActiGraph GT3X+ accelerometer records at baseline and 20 weeks. Data were analysed by intention to treat comparing between groups using hierarchical linear modelling.RESULTS Participants were n=101, 52 males, mean age 11 years 3 months (SD 2y 4mo).Intervention participants completed a mean 32.4 hours (SD 17.2) of training, associated with significant improvements in functional strength (mean difference 19.3 repetitions; 95% confidence interval [CI] 10.8-27.7; p<0.001) and 6MWT distance (mean difference 38.9m; 95% CI 12.3-51.9; p<0.001) compared with the control group at 20 weeks, although not activity performance (p>0.05). INTERPRETATIONTraining was effective at increasing functional strength and walking endurance in independently ambulant children with unilateral CP. This did not translate into improvements in activity performance.Cerebral palsy (CP) describes a group of disorders of the development of movement and posture, causing activity limitations.
Chloride intracellular channel 3 (CLIC3) drives invasiveness of pancreatic and ovarian cancer by acting in concert with Rab25 to regulate the recycling of a5b1 integrin from late endosomes to the plasma membrane. Here, we show that in two estrogen receptor (ER)-negative breast cancer cell lines, CLIC3 has little influence on integrin recycling, but controls trafficking of the pro-invasive matrix metalloproteinase MT1-MMP (also known as MMP14). In MDA-MB-231 cells, MT1-MMP and CLIC3 are localized primarily to late endosomal/lysosomal compartments located above the plane of adhesion and near the nucleus. MT1-MMP is transferred from these late endosomes to sites of cell-matrix adhesion in a CLIC3-dependent fashion. Correspondingly, CLIC3-knockdown opposes MT1-MMP-dependent invasive processes. These include the disruption of the basement membrane as acini formed from MCF10DCIS.com cells acquire invasive characteristics in 3D culture, and the invasion of MDA-MB-231 cells into Matrigel or organotypic plugs of type I collagen. Consistent with this, expression of CLIC3 predicts poor prognosis in ER-negative breast cancer. The identification of MT1-MMP as a cargo of a CLIC3-regulated pathway that drives invasion highlights the importance of late endosomal sorting and trafficking in breast cancer.
IntroductionPersons with cerebral palsy require a lifetime of costly and resource intensive interventions which are often limited by equity of access. With increasing burden being placed on health systems, new methods to deliver intensive rehabilitation therapies are needed. Move it to improve it (Mitii) is an internet-based multimodal programme comprising upper-limb and cognitive training with physical activity. It can be accessed in the client's home at their convenience. The proposed study aims to test the efficacy of Mitii in improving upper-limb function and motor planning. Additionally, this study hopes to further our understanding of the central neurovascular mechanisms underlying the proposed changes and determine the cost effectiveness of Mitii.Methods and analysisChildren with congenital hemiplegia will be recruited to participate in this waitlist control, matched pairs, single-blind randomised trial. Children be matched at baseline and randomly allocated to receive 20 weeks of 30 min of daily Mitii training immediately, or waitlisted for 20 weeks before receiving the same Mitii training (potential total dose=70 h). Outcomes will be assessed at 20 weeks after the start of Mitii, and retention effects tested at 40 weeks. The primary outcomes will be the Assessment of Motor and Process Skills (AMPS), the Assisting Hand Assessment (AHA) and unimanual upper-limb capacity using the Jebsen-Taylor Test of Hand Function (JTTHF). Advanced brain imaging will assess use-dependant neuroplasticity. Measures of body structure and functions, activity, participation and quality of life will be used to assess Mitii efficacy across all domains of the International Classification of Functioning, Disability and Health framework.Ethics and disseminationThis project has received Ethics Approval from the Medical Ethics Committee of The University of Queensland (2011000608) and the Royal Children's Hospital Brisbane (HREC/11/QRCH/35). Findings will be disseminated widely through conference presentations, seminars and peer-reviewed scientific journals.Trial registrationACTRN12611001174976
SummaryExpression of the initiator methionine tRNA (tRNAiMet) is deregulated in cancer. Despite this fact, it is not currently known how tRNAiMet expression levels influence tumor progression. We have found that tRNAiMet expression is increased in carcinoma-associated fibroblasts, implicating deregulated expression of tRNAiMet in the tumor stroma as a possible contributor to tumor progression. To investigate how elevated stromal tRNAiMet contributes to tumor progression, we generated a mouse expressing additional copies of the tRNAiMet gene (2+tRNAiMet mouse). Growth and vascularization of subcutaneous tumor allografts was enhanced in 2+tRNAiMet mice compared with wild-type littermate controls. Extracellular matrix (ECM) deposited by fibroblasts from 2+tRNAiMet mice supported enhanced endothelial cell and fibroblast migration. SILAC mass spectrometry indicated that elevated expression of tRNAiMet significantly increased synthesis and secretion of certain types of collagen, in particular type II collagen. Suppression of type II collagen opposed the ability of tRNAiMet-overexpressing fibroblasts to deposit pro-migratory ECM. We used the prolyl hydroxylase inhibitor ethyl-3,4-dihydroxybenzoate (DHB) to determine whether collagen synthesis contributes to the tRNAiMet-driven pro-tumorigenic stroma in vivo. DHB had no effect on the growth of syngeneic allografts in wild-type mice but opposed the ability of 2+tRNAiMet mice to support increased angiogenesis and tumor growth. Finally, collagen II expression predicts poor prognosis in high-grade serous ovarian carcinoma. Taken together, these data indicate that increased tRNAiMet levels contribute to tumor progression by enhancing the ability of stromal fibroblasts to synthesize and secrete a type II collagen-rich ECM that supports endothelial cell migration and angiogenesis.
The role of glutaminolysis in providing metabolites to support tumour growth is well-established, but the involvement of glutamine metabolism in invasive processes is yet to be elucidated. Here we show that normal mammary epithelial cells consume glutamine, but do not secrete glutamate. Indeed, low levels of extracellular glutamate are necessary to maintain epithelial homoeostasis, and provision of glutamate drives disruption of epithelial morphology and promotes key characteristics of the invasive phenotype such as lumen-filling and basement membrane disruption. By contrast, primary cultures of invasive breast cancer cells convert glutamine to glutamate which is released from the cell through the system Xc- antiporter to activate a metabotropic glutamate receptor. This contributes to the intrinsic aggressiveness of these cells by upregulating Rab27-dependent recycling of the transmembrane matrix metalloprotease, MT1-MMP to promote invasive behaviour leading to basement membrane disruption. These data indicate that acquisition of the ability to release glutamate is a key watershed in disease aggressiveness.
The Rab GTPase effector, Rab-coupling protein (RCP) is known to promote invasive behaviour in vitro by controlling integrin and receptor tyrosine kinase (RTK) trafficking, but how RCP influences metastasis in vivo is unclear. Here we identify an RTK of the Eph family, EphA2, to be a cargo of an RCP-regulated endocytic pathway which controls cell:cell repulsion and metastasis in vivo. Phosphorylation of RCP at Ser435 by Lemur tyrosine kinase-3 (LMTK3) and of EphA2 at Ser897 by Akt are both necessary to promote Rab14-dependent (and Rab11-independent) trafficking of EphA2 which generates cell:cell repulsion events that drive tumour cells apart. Genetic disruption of RCP or EphA2 opposes cell:cell repulsion and metastasis in an autochthonous mouse model of pancreatic adenocarcinoma—whereas conditional knockout of another RCP cargo, α5 integrin, does not suppress pancreatic cancer metastasis—indicating a role for RCP-dependent trafficking of an Eph receptor to drive tumour dissemination in vivo.
AIM This study aimed to quantify the contribution of physical, personal and environmental characteristics to physical activity among independently ambulant children with unilateral cerebral palsy (CP).METHOD One-hundred and two children with unilateral CP (52 males, 50 females; 52 right hemiplegia; mean age 11y 3mo, range 8-17y [SD 2y 4mo]) classified at Gross Motor Function Classification System (GMFCS) levels I = 44 and II = 58 participated. Physical activity was measured over 4 days using ActiGraph accelerometers recording as activity counts. GMFCS, functional strength, 6-minute walk test (6MWT), mobility limitations (MobQues28), age, sex, Assessment of Life-Habits recreation domain, Participation and Environment Measure for Children and Youth (PEM-CY) and environmental characteristics were considered for selection in a linear regression model. These served as independent variables which were determined using a backwards selection procedure. RESULTSYounger age, male sex, increased performance on the 6MWT, and increased participation in the home and community measured using the PEM-CY were significantly associated with activity counts (p<0.001). However, the model fit was somewhat weak (R 2 =0.32), indicating that much of the variation was unexplained. Older age and reduced community participation were associated with high inactivity (p<0.001).
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