Optimising the chick chorioallantoic membrane xenograft model of neuroblastoma for drug delivery

Background Neuroblastoma is a paediatric cancer that despite multimodal therapy still has a poor outcome for many patients with high risk tumours. Retinoic acid (RA) promotes differentiation of some neuroblastoma tumours and cell lines, and is successfully used clinically, supporting the view that differentiation therapy is a promising strategy for treatment of neuroblastoma. To improve treatment of a wider range of tumour types, development and testing of novel differentiation agents is essential. New pre-clinical models are therefore required to test therapies in a rapid cost effective way in order to identify the most useful agents. Methods As a proof of principle, differentiation upon ATRA treatment of two MYCN-amplified neuroblastoma cell lines, IMR32 and BE2C, was measured both in cell cultures and in tumours formed on the chick chorioallantoic membrane (CAM). Differentiation was assessed by 1) change in cell morphology, 2) reduction in cell proliferation using Ki67 staining and 3) changes in differentiation markers (STMN4 and ROBO2) and stem cell marker (KLF4). Results were compared to MLN8237, a classical Aurora Kinase A inhibitor. For the in vivo experiments, cells were implanted on the CAM at embryonic day 7 (E7), ATRA treatment was between E11 and E13 and tumours were analysed at E14. Results Treatment of IMR32 and BE2C cells in vitro with 10 μM ATRA resulted in a change in cell morphology, a 65% decrease in cell proliferation, upregulation of STMN4 and ROBO2 and downregulation of KLF4. ATRA proved more effective than MLN8237 in these assays. In vivo, 100 μM ATRA repetitive treatment at E11, E12 and E13 promoted a change in expression of differentiation markers and reduced proliferation by 43% (p < 0.05). 40 μM ATRA treatment at E11 and E13 reduced proliferation by 37% (p < 0.05) and also changed cell morphology within the tumour. Conclusion Differentiation of neuroblastoma tumours formed on the chick CAM can be analysed by changes in cell morphology, proliferation and gene expression. The well-described effects of ATRA on neuroblastoma differentiation were recapitulated within 3 days in the chick embryo model, which therefore offers a rapid, cost effective model compliant with the 3Rs to select promising drugs for further preclinical analysis

Assessing the Efficacy of Nano- and Micro-Sized Magnetic Particles as Contrast Agents for MRI Cell Tracking

Iron-oxide based contrast agents play an important role in magnetic resonance imaging (MRI) of labelled cells in vivo. Currently, a wide range of such contrast agents is available with sizes varying from several nanometers up to a few micrometers and consisting of single or multiple magnetic cores. Here, we evaluate the effectiveness of these different particles for labelling and imaging stem cells, using a mouse mesenchymal stem cell line to investigate intracellular uptake, retention and processing of nano- and microsized contrast agents. The effect of intracellular confinement on transverse relaxivity was measured by MRI at 7 T and in compliance with the principles of the ‘3Rs’, the suitability of the contrast agents for MR-based cell tracking in vivo was tested using a chick embryo model. We show that for all particles tested, relaxivity was markedly reduced following cellular internalisation, indicating that contrast agent relaxivity in colloidal suspension does not accurately predict performance in MR-based cell tracking studies. Using a bimodal imaging approach comprising fluorescence and MRI, we demonstrate that labelled MSC remain viable following in vivo transplantation and can be tracked effectively using MRI. Importantly, our data suggest that larger particles might confer advantages for longer-term imaging

100% RAG: Architectural Education | Historians and Critics, Volume 2, Number 6

100% RAG: Architectural Education | Historians and Critics, Syracuse School of Architecture, Student Newspaper, Volume 2, Number 6. Student newsletter from student contributors of Syracuse School of Architecture in 1977

CDK inhibitors reduce cell proliferation and reverse hypoxia-induced metastasis of neuroblastoma tumours in a chick embryo model

Abstract Neuroblastoma is a paediatric cancer with a poor prognosis. This is in part due to the widespread metastasis at time of presentation, which is refractory to current treatment modalities. New therapeutic agents that can control not only tumour growth but also metastasis are urgently needed. One current therapeutic option used in the clinic is differentiation therapy with retinoic acid, where the terminal differentiation of the neuroblastoma cells reduces tumour growth in the primary tumour as well as at metastatic sites. However, retinoic acid only works in a subset of patients. We investigated the potential of CDK inhibitors on neuroblastoma cell differentiation, tumour progression and metastasis by utilising a 3R compliant cost effective preclinical chick embryo model. In both SK-N-AS and BE(2)C cell lines, when engrafted on the chorioallantoic membrane of chick embryos, we observed a reduction of tumour cell proliferation as well as a reduction in hypoxia preconditioning-driven metastasis by 60%. In addition, the expression of a panel of genes with known roles in metastasis, which increased upon hypoxia-preconditioning, was largely reduced by a CDK1 inhibitor. These results provide a promising alternative to currently existing therapies and might aid the development of new treatment protocols for retinoic acid-resistant patients

100% RAG: Architectural Education | THE SCHOOLS, Volume 2, Number 5

100% RAG: Architectural Education | THE SCHOOLS, Syracuse School of Architecture, Student Newspaper, Volume 2, Number 5. Student newsletter from student contributors of Syracuse School of Architecture in 1977

100% RAG: Architectural Education | Theory vs. Practice, Volume 2, Number 4

100% RAG: Architectural Education | Theory vs. Practice, Syracuse School of Architecture, Student Newspaper, Volume 2, Number 4. Student newsletter from student contributors of Syracuse School of Architecture in 1977

CT694 and pgp3 as Serological Tools for Monitoring Trachoma Programs.

Defining endpoints for trachoma programs can be a challenge as clinical signs of infection may persist in the absence of detectable bacteria. Antibody-based tests may provide an alternative testing strategy for surveillance during terminal phases of the program. Antibody-based assays, in particular ELISAs, have been shown to be useful to document C. trachomatis genital infections, but have not been explored extensively for ocular C. trachomatis infections. An antibody-based multiplex assay was used to test two C. trachomatis antigens, pgp3 and CT694, for detection of trachoma antibodies in bloodspots from Tanzanian children (n = 160) collected after multiple rounds of mass azithromycin treatment. Using samples from C. trachomatis-positive (by PCR) children from Tanzania (n = 11) and control sera from a non-endemic group of U.S. children (n = 122), IgG responses to both pgp3 and CT694 were determined to be 91% sensitive and 98% specific. Antibody responses of Tanzanian children were analyzed with regard to clinical trachoma, PCR positivity, and age. In general, children with more intense ocular pathology (TF/TI = 2 or most severe) had a higher median antibody response to pgp3 (p = 0.0041) and CT694 (p = 0.0282) than those with normal exams (TF/TI = 0). However, 44% of children with no ocular pathology tested positive for antibody, suggesting prior infection. The median titer of antibody responses for children less than three years of age was significantly lower than those of older children. (p<0.0001 for both antigens). The antibody-based multiplex assay is a sensitive and specific additional tool for evaluating trachoma transmission. The assay can also be expanded to include antigens representing different diseases, allowing for a robust assay for monitoring across NTD programs