The transcriptional co-repressor Runx1t1 is essential for MYCN-driven neuroblastoma tumorigenesis.

MYCN oncogene amplification is frequently observed in aggressive childhood neuroblastoma. Using an unbiased large-scale mutagenesis screen in neuroblastoma-prone transgenic mice, we identify a single germline point mutation in the transcriptional corepressor Runx1t1, which abolishes MYCN-driven tumorigenesis. This loss-of-function mutation disrupts a highly conserved zinc finger domain within Runx1t1. Deletion of one Runx1t1 allele in an independent Runx1t1 knockout mouse model is also sufficient to prevent MYCN-driven neuroblastoma development, and reverse ganglia hyperplasia, a known pre-requisite for tumorigenesis. Silencing RUNX1T1 in human neuroblastoma cells decreases colony formation in vitro, and inhibits tumor growth in vivo. Moreover, RUNX1T1 knockdown inhibits the viability of PAX3-FOXO1 fusion-driven rhabdomyosarcoma and MYC-driven small cell lung cancer cells. Despite the role of Runx1t1 in MYCN-driven tumorigenesis neither gene directly regulates the other. We show RUNX1T1 forms part of a transcriptional LSD1-CoREST3-HDAC repressive complex recruited by HAND2 to enhancer regions to regulate chromatin accessibility and cell-fate pathway genes.

Collaborative Active Learning Activities Promote Deep Learning in a Chemistry-Biochemistry Course.

Currently in higher education, there is a move towards providing more student-centred learning experiences, where students are actively involved in the learning process. To promote learner engagement and communication between peers, many educators utilise collaborative active learning activities. This study aimed to demonstrate that an active learning curriculum developed for a Chemistry-Biochemistry unit, allowed students to gain a deep understanding of the content, while developing key academic skills. In each face-to-face session of the Chemistry-Biochemistry unit, students participated in collaborative active learning activities including Participation+ and a variety of Padlet activities. The students were also challenged to develop their written communication skills, by taking part in a formative In-Class Writing Task. Survey results indicated that the active learning curriculum provided an engaging, interactive environment that was conducive to the students developing an understanding of the course's underlying concepts and developing key academic skills. The students communicated their deep understanding of the content verbally during active learning activities and in writing during the In-Class Writing Task, written assignment and final exam. Students who consistently communicated deep knowledge of the content during the In-Class Writing Task achieved high marks on the summative written assignment, final exam and unit total. This study clearly demonstrates that the active learning curriculum employed in the Chemistry-Biochemistry unit provided a collaborative and engaging learning environment, where many students developed a deep understanding of the content and acquired the skills to communicate their knowledge both orally and through written communication.

Glutathione biosynthesis is upregulated at the initiation of MYCN-driven neuroblastoma tumorigenesis.

The MYCN gene is amplified and overexpressed in a large proportion of high stage neuroblastoma patients and has been identified as a key driver of tumorigenesis. However, the mechanism by which MYCN promotes tumor initiation is poorly understood. Here we conducted metabolic profiling of pre-malignant sympathetic ganglia and tumors derived from the TH-MYCN mouse model of neuroblastoma, compared to non-malignant ganglia from wildtype littermates. We found that metabolites involved in the biosynthesis of glutathione, the most abundant cellular antioxidant, were the most significantly upregulated metabolic pathway at tumor initiation, and progressively increased to meet the demands of tumorigenesis. A corresponding increase in the expression of genes involved in ribosomal biogenesis suggested that MYCN-driven transactivation of the protein biosynthetic machinery generated the necessary substrates to drive glutathione biosynthesis. Pre-malignant sympathetic ganglia from TH-MYCN mice had higher antioxidant capacity and required glutathione upregulation for cell survival, when compared to wildtype ganglia. Moreover, in vivo administration of inhibitors of glutathione biosynthesis significantly delayed tumorigenesis when administered prophylactically and potentiated the anticancer activity of cytotoxic chemotherapy against established tumors. Together these results identify enhanced glutathione biosynthesis as a selective metabolic adaptation required for initiation of MYCN-driven neuroblastoma, and suggest that glutathione-targeted agents may be used as a potential preventative strategy, or as an adjuvant to existing chemotherapies in established disease.

Management of knee osteoarthritis by combined stromal vascular fraction cell therapy, platelet-rich plasma, and musculoskeletal exercises: a case series.

INTRODUCTION: Knee osteoarthritis is associated with persistent joint pain, stiffness, joint deformities, ligament damage, and surrounding muscle atrophy. The complexity of the disease makes treatment difficult. There are no therapeutic drugs available to halt the disease progression, leaving patients dependent on pain medication, anti-inflammatory drugs, or invasive joint replacement surgery. CASE PRESENTATIONS: Four patients with a history of unresolved symptomatic knee osteoarthritis were investigated for the therapeutic outcome of combining an exercise rehabilitation program with intra-articular injections of autologous StroMed (ie, stromal vascular fraction cells concentrated by ultrasonic cavitation from lipoaspirate) and platelet-rich plasma (PRP). The Knee Injury and Osteoarthritis Outcome Score questionnaire (KOOS) was administered along with physical function tests over a 12-month period. The first patient achieved a maximum therapeutic outcome of 100 in all five KOOS subscales (left knee), and 100 for four subscales (right knee). The second patient scored 100 in all five KOOS subscales (left knee), and greater than 84 in all subscales (right knee). Treatment of the third patient resulted in improved outcomes in both knees of >93 for four KOOS subscales, and 60 for the Function in Sport and Recreation subscale. The fourth patient improved to 100 in all five KOOS subscales. In all patients, the physical function "Get-up and Go" test and "Stair Climbing Test" returned to normal (a value of zero). CONCLUSION: This case series indicates that improved outcomes may be obtained when autologous stromal vascular fraction (StroMed) cell therapy is combined with traditional exercise practices and PRP for osteoarthritis. Of the seven joints treated: all patients' scores of pain improved to >96; and quality of life scores to >93. Functional performance measures of mobility returned to normal. This simple treatment appears to be extremely effective for osteoarthritis disorders that have no drug treatment to halt disease progression.

Serial transcriptome analysis and cross-species integration identifies centromere-associated protein E as a novel neuroblastoma target.

Cancer genomic studies that rely on analysis of biopsies from primary tumors may not fully identify the molecular events associated with tumor progression. We hypothesized that characterizing the transcriptome during tumor progression in the TH-MYCN transgenic model would identify oncogenic drivers that would be targetable therapeutically. We quantified expression of 32,381 murine genes in nine hyperplastic ganglia harvested at three time points and four tumor cohorts of progressively larger size in mice homozygous for the TH-MYCN transgene. We found 93 genes that showed a linearly increasing or decreasing pattern of expression from the preneoplastic ganglia to end stage tumors. Cross-species integration identified 24 genes that were highly expressed in human MYCN-amplified neuroblastomas. The genes prioritized were not exclusively driven by increasing Myc transactivation or proliferative rate. We prioritized three targets [centromere-associated protein E (Cenpe), Gpr49, and inosine monophosphate dehydrogenase type II] with previously determined roles in cancer. Using siRNA knockdown in human neuroblastoma cell lines, we further prioritized CENPE due to inhibition of cellular proliferation. Targeting CENPE with the small molecular inhibitor GSK923295 showed inhibition of in vitro proliferation of 19 neuroblastoma cell lines (median IC(50), 41 nmol/L; range, 27-266 nmol/L) and delayed tumor growth in three xenograft models (P values ranged from P < 0.0001 to P = 0.018). We provide preclinical validation that serial transcriptome analysis of a transgenic mouse model followed by cross-species integration is a useful method to identify therapeutic targets and identify CENPE as a novel therapeutic candidate in neuroblastoma.

Role of melanotransferrin in iron metabolism: studies using targeted gene disruption in vivo.

Melanotransferrin (MTf) or tumor antigen p97 is a transferrin homolog that binds one iron (Fe) atom and has been suggested to play roles in a variety of processes, including Fe metabolism, eosinophil differentiation, and plasminogen activation. Considering the vital role of Fe in many metabolic pathways, such as DNA and heme synthesis, it is important to understand the function of MTf. To define this, a MTf knockout (MTf-/-) mouse was generated through targeted disruption of the MTf gene. The MTf-/- mice were viable and fertile and developed normally, with no morphologic or histologic abnormalities. Assessment of Fe indices, tissue Fe levels, hematology, and serum chemistry parameters demonstrated no differences between MTf-/- and wild-type (MTf+/+) mice, suggesting MTf was not essential for Fe metabolism.

The soluble form of the membrane-bound transferrin homologue, melanotransferrin, inefficiently donates iron to cells via nonspecific internalization and degradation of the protein.

Melanotransferrin (MTf) is a membrane-bound transferrin (Tf) homologue found particularly in melanoma cells. Apart from membrane-bound MTf, a soluble form of the molecule (sMTf) has been identified in vitro[Food, M.R., Rothenberger, S., Gabathuler, R., Haidl, I.D., Reid, G. & Jefferies, W.A. (1994) J. Biol. Chem.269, 3034-3040] and in vivo in Alzheimer's disease. However, nothing is known about the function of sMTf or its role in Fe uptake. In this study, sMTf labelled with 59Fe and 125I was used to examine its ability to donate 59Fe to SK-Mel-28 melanoma cells and other cell types. sMTf donated 59Fe to cells at 14% of the rate of Tf. Analysis of sMTf binding showed that unlike Tf, sMTf did not bind to a saturable Tf-binding site. Studies with Chinese hamster ovary cells with and without specific Tf receptors showed that unlike Tf, sMTf did not donate its 59Fe via these pathways. This was confirmed by experiments using lysosomotropic agents that markedly reduced 59Fe uptake from Tf, but had far less effect on 59Fe uptake from sMTf. In addition, an excess of 56Fe-labelled Tf or sMTf had no effect on 125I-labelled sMTf uptake, suggesting a nonspecific interaction of sMTf with cells. Protein-free 125I determinations demonstrated that in contrast with Tf, sMTf was markedly degraded. We suggest that unlike the binding of Tf to specific receptors, sMTf was donating Fe to cells via an inefficient mechanism involving nonspecific internalization and subsequent degradation.