Pharmacological inhibition of RAS overcomes FLT3 inhibitor resistance in FLT3-ITD+ AML through AP-1 and RUNX1

AML is characterized by mutations in genes associated with growth regulation such as internal tandem duplications (ITD) in the receptor kinase FLT3. Inhibitors targeting FLT3 (FLT3i) are being used to treat patients with FLT3-ITD+ but most relapse and become resistant. To elucidate the resistance mechanism, we compared the gene regulatory networks (GRNs) of leukemic cells from patients before and after relapse, which revealed that the GRNs of drug-responsive patients were altered by rewiring their AP-1-RUNX1 axis. Moreover, FLT3i induces the upregulation of signaling genes, and we show that multiple cytokines, including interleukin-3 (IL-3), can overcome FLT3 inhibition and send cells back into cycle. FLT3i leads to loss of AP-1 and RUNX1 chromatin binding, which is counteracted by IL-3. However, cytokine-mediated drug resistance can be overcome by a pan-RAS inhibitor. We show that cytokines instruct AML growth via the transcriptional regulators AP-1 and RUNX1 and that pan-RAS drugs bypass this barrier.

Gene regulatory network analysis predicts cooperating transcription factor regulons required for FLT3-ITD+ AML growth

Acute myeloid leukemia (AML) is a heterogeneous disease caused by different mutations. Previously, we showed that each mutational subtype develops its specific gene regulatory network (GRN) with transcription factors interacting within multiple gene modules, many of which are transcription factor genes themselves. Here, we hypothesize that highly connected nodes within such networks comprise crucial regulators of AML maintenance. We test this hypothesis using FLT3-ITD-mutated AML as a model and conduct an shRNA drop-out screen informed by this analysis. We show that AML-specific GRNs predict crucial regulatory modules required for AML growth. Furthermore, our work shows that all modules are highly connected and regulate each other. The careful multi-omic analysis of the role of one (RUNX1) module by shRNA and chemical inhibition shows that this transcription factor and its target genes stabilize the GRN of FLT3-ITD+ AML and that its removal leads to GRN collapse and cell death.

A human mesenchymal spheroid prototype to replace moderate severity animal procedures in leukaemia drug testing

Patient derived xenograft (PDX) models are regarded as gold standard preclinical models in leukaemia research, especially in testing new drug combinations where typically 45-50 mice are used per assay. 9000 animal experiments are performed annually in the UK in leukaemia research with these expensive procedures being classed as moderate severity, meaning they cause significant pain, suffering and visible distress to animal's state. Furthermore, not all clinical leukaemia samples engraft and when they do data turnaround time can be between 6-12 months. Heavy dependence on animal models is because clinical leukaemia samples do not proliferate in vitro. Alternative cell line models though popular for drug testing are not biomimetic - they are not dependent on the microenvironment for survival, growth and treatment response and being derived from relapse samples they do not capture the molecular complexity observed at disease presentation. Here we have developed an in vitro platform to rapidly establish co-cultures of patient-derived leukaemia cells with 3D bone marrow mesenchyme spheroids, BM-MSC-spheroids.  We optimise protocols for developing MSC-spheroid leukaemia co-culture using clinical samples and deliver drug response data within a week. Using three patient samples representing distinct cytogenetics we show that patient-derived-leukaemia cells show enhanced proliferation when co-cultured with MSC-spheroids. In addition, MSC-spheroids provided improved protection against treatment. This makes our spheroids suitable to model treatment resistance - a major hurdle in current day cancer management Given this 3Rs approach is 12 months faster (in delivering clinical data), is a human cell-based biomimetic model and uses 45-50 fewer animals/drug-response assay the anticipated target end-users would include academia and pharmaceutical industry. This animal replacement prototype would facilitate clinically translatable research to be performed with greater ethical, social and financial sustainability.

The MLL-Menin Interaction is a Therapeutic Vulnerability in NUP98-rearranged AML

Chromosomal translocations involving the NUP98 locus are among the most prevalent rearrangements in pediatric acute myeloid leukemia (AML). AML with NUP98 fusions is characterized by high expression of HOXA and MEIS1 genes and is associated with poor clinical outcome. NUP98 fusion proteins are recruited to their target genes by the mixed lineage leukemia (MLL) complex, which involves a direct interaction between MLL and Menin. Here, we show that therapeutic targeting of the Menin-MLL interaction inhibits the propagation of NUP98-rearrranged AML both ex vivo and in vivo. Treatment of primary AML cells with the Menin inhibitor revumenib (SNDX-5613) impairs proliferation and clonogenicity ex vivo in long-term coculture and drives myeloid differentiation. These phenotypic effects are associated with global gene expression changes in primary AML samples that involve the downregulation of many critical NUP98 fusion protein-target genes, such as MEIS1 and CDK6. In addition, Menin inhibition reduces the expression of both wild-type FLT3 and mutated FLT3-ITD, and in combination with FLT3 inhibitor, suppresses patient-derived NUP98-r AML cells in a synergistic manner. Revumenib treatment blocks leukemic engraftment and prevents leukemia-associated death of immunodeficient mice transplanted with NUP98::NSD1 FLT3-ITD-positive patient-derived AML cells. These results demonstrate that NUP98-rearranged AMLs are highly susceptible to inhibition of the MLL-Menin interaction and suggest the inclusion of AML patients harboring NUP98 fusions into the clinical evaluation of Menin inhibitors.

Gene regulatory network analysis predicts cooperating transcription factor regulons required for FLT3-ITD+ AML growth

AML is a heterogenous disease caused by different mutations. We have previously shown that each mutational sub-type develops its specific gene regulatory network (GRN) with transcription factors interacting with multiple gene modules, many of which are transcription factor genes themselves. Here we hypothesized that highly connected nodes within such networks comprise crucial regulators of AML maintenance. We tested this hypothesis using FLT3-ITD mutated AML as a model and conducted an shRNA drop-out screen informed by this analysis. We show that AML-specific GRNs predict identifying crucial regulatory modules required for AML but not normal cellular growth. Furthermore, our work shows that all modules are highly connected and regulate each other. The careful multi-omic analysis of the role of one (RUNX1) module by shRNA and chemical inhibition shows that this transcription factor and its target genes stabilize the GRN of FLT3-ITD AML and that its removal leads to GRN collapse and cell death.

Nanoparticle-mediated targeting of the fusion gene RUNX1/ETO in t(8;21)-positive acute myeloid leukaemia

A hallmark of acute myeloid leukaemias (AMLs) are chromosomal rearrangements that give rise to novel leukaemia-specific fusion genes. Most of these fusion genes are both initiating and driving events in AML and therefore constitute ideal therapeutic targets but are challenging to target by conventional drug development. siRNAs are frequently used for the specific suppression of fusion gene expression but require special formulations for efficient in vivo delivery. Here we describe the use of siRNA-loaded lipid nanoparticles for the specific therapeutic targeting of the leukaemic fusion gene RUNX1/ETO. Transient knockdown of RUNX1/ETO reduces its binding to its target genes and alters the binding of RUNX1 and its co-factor CBFβ. Transcriptomic changes in vivo were associated with substantially increased median survival of a t(8;21)-AML mouse model. Importantly, transient knockdown in vivo causes long-lasting inhibition of leukaemic proliferation and clonogenicity, induction of myeloid differentiation and a markedly impaired re-engraftment potential in vivo. These data strongly suggest that temporary inhibition of RUNX1/ETO results in long-term restriction of leukaemic self-renewal. Our results provide proof for the feasibility of targeting RUNX1/ETO in a pre-clinical setting and support the further development of siRNA-LNPs for the treatment of fusion gene-driven malignancies.

Biallelic TET2 mutations confer sensitivity to 5'-azacitidine in acute myeloid leukemia

Precision medicine can significantly improve outcomes for patients with cancer, but implementation requires comprehensive characterization of tumor cells to identify therapeutically exploitable vulnerabilities. Here, we describe somatic biallelic TET2 mutations in an elderly patient with acute myeloid leukemia (AML) that was chemoresistant to anthracycline and cytarabine but acutely sensitive to 5'-azacitidine (5'-Aza) hypomethylating monotherapy, resulting in long-term morphological remission. Given the role of TET2 as a regulator of genomic methylation, we hypothesized that mutant TET2 allele dosage affects response to 5'-Aza. Using an isogenic cell model system and an orthotopic mouse xenograft, we demonstrate that biallelic TET2 mutations confer sensitivity to 5'-Aza compared with cells with monoallelic mutations. Our data argue in favor of using hypomethylating agents for chemoresistant disease or as first-line therapy in patients with biallelic TET2-mutated AML and demonstrate the importance of considering mutant allele dosage in the implementation of precision medicine for patients with cancer.

hiPSC-derived bone marrow milieu identifies a clinically actionable driver of niche-mediated treatment resistance in leukemia

Leukemia cells re-program their microenvironment to augment blast proliferation and enhance treatment resistance. Means of clinically targeting such niche-driven treatment resistance remain ambiguous. We develop human induced pluripotent stem cell (hiPSC)-engineered niches to reveal druggable cancer-niche dependencies. We reveal that mesenchymal (iMSC) and vascular niche-like (iANG) hiPSC-derived cells support ex vivo proliferation of patient-derived leukemia cells, affect dormancy, and mediate treatment resistance. iMSCs protect dormant and cycling blasts against dexamethasone, while iANGs protect only dormant blasts. Leukemia proliferation and protection from dexamethasone-induced apoptosis is dependent on cancer-niche interactions mediated by CDH2. Consequently, we test CDH2 antagonist ADH-1 (previously in Phase I/II trials for solid tumors) in a very aggressive patient-derived xenograft leukemia mouse model. ADH-1 shows high in vivo efficacy; ADH-1/dexamethasone combination is superior to dexamethasone alone, with no ADH-1-conferred additional toxicity. These findings provide a proof-of-concept starting point to develop improved, potentially safer therapeutics targeting niche-mediated cancer dependencies in blood cancers.

MEDB-79. MYC-driven upregulation of thede novo serine and glycine pathway is a novel therapeutic target for Group 3 MYC-amplified Medulloblastoma

Despite advances in the molecular sub-classification and risk-stratification of medulloblastoma (MB), a subset of tumours remain refractory to current multimodal therapies. Group 3 (MB_Group3) patients represent around 25% of MBs, and amplification and elevated expression of MYC in this group correlates with dismal clinical outcomes. Since direct targeting of MYC remains elusive, understanding and exploiting metabolic dependencies in MYC-amplified MB_Group3 may reveal novel therapeutic opportunities. We engineered three independent regulable MYC-amplified MB_Group3 cell-based models, each harbouring doxycycline-inducible anti-MYC shRNAs (two independent species) or a non-silencing shRNA control. In all three models, MYC knockdown (KD) revealed persistent MYC-dependent cancer phenotypes, reduction in proliferation and cell cycle progression. We utilised ¹H high-resolution magic angle spectroscopy (HRMAS) and stable isotope-resolved metabolomics to assess changes in intracellular metabolites and pathway dynamics when MYC expression was modulated. Profiling revealed consistent MYC-dependent changes in metabolite concentrations across models. Notably, glycine was consistently accumulated following MYC KD suggesting altered pathway dynamics. ¹³C-glucose tracing further revealed a reduction in glucose-derived serine and glycine (de novo synthesis) following MYC KD which was attributable to lower expression of PHGDH, the rate-limiting enzyme of this pathway. Furthermore, in human primary tumours, elevated expression of PHGDH was associated with MYC amplification and poorer survival outcomes. MYC expressing cells showed greater sensitivity to pharmacological inhibition of PHGDH compared to MYC KD (MB_Group3) and MB_SHH subgroup cell lines in vitro. Critically, targeting PHGDH in vivo, using MYC-dependent xenografts and genetically engineered mouse models, consistently slowed tumour progression and increased survival. In summary, metabolic profiling has uncovered MYC-dependent metabolic alterations and revealed the de novo serine/glycine synthesis pathway as a novel and clinically relevant therapeutic target in MYC-amplified MB_Group3. Together, these findings reveal metabolic vulnerabilities of MYC-amplified MB_Group3 which represent novel therapeutic opportunities for this poor-prognosis disease group.

Paediatric Burkitt lymphoma patient-derived xenografts capture disease characteristics over time and are a model for therapy

Burkitt lymphoma (BL) accounts for almost two-thirds of all B-cell non-Hodgkin lymphoma (B-NHL) in children and adolescents and is characterised by a MYC translocation and rapid cell turnover. Intensive chemotherapeutic regimens have been developed in recent decades, including the lymphomes malins B (LMB) protocol, which have resulted in a survival rate in excess of 90%. Recent clinical trials have focused on immunochemotherapy, with the addition of rituximab to chemotherapeutic backbones, showing encouraging results. Despite these advances, relapse and refractory disease occurs in up to 10% of patients and salvage options for these carry a dismal prognosis. Efforts to better understand the molecular and functional characteristics driving relapse and refractory disease may help improve this prognosis. This study has established a paediatric BL patient-derived xenograft (PDX) resource which captures and maintains tumour heterogeneity, may be used to better characterise tumours and identify cell populations responsible for therapy resistance.

Exposure of Patient-Derived Mesenchymal Stromal Cells to TGFB1 Supports Fibrosis Induction in a Pediatric Acute Megakaryoblastic Leukemia Model

Bone marrow fibrosis (BMF) is a rare complication in acute leukemia. In pediatrics, it predominantly occurs in acute megakaryoblastic leukemia (AMKL) and especially in patients with trisomy 21, called myeloid leukemia in Down syndrome (ML-DS). Defects in mesenchymal stromal cells (MSC) and cytokines specifically released by the myeloid blasts are thought to be the main drivers of fibrosis in the bone marrow niche (BMN). To model the BMN of pediatric patients with AMKL in mice, we first established MSCs from pediatric patients with AMKL (n = 5) and ML-DS (n = 9). Healthy donor control MSCs (n = 6) were generated from unaffected children and adolescents ≤18 years of age. Steady-state analyses of the MSCs revealed that patient-derived MSCs exhibited decreased adipogenic differentiation potential and enrichment of proliferation-associated genes. Importantly, TGFB1 exposure in vitro promoted early profibrotic changes in all three MSC entities. To study BMF induction for longer periods of time, we created an in vivo humanized artificial BMN subcutaneously in immunodeficient NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ mice, using a mixture of MSCs, human umbilical vein endothelial cell, and Matrigel. Injection of AMKL blasts as producers of TGFB1 into this BMN after 8 weeks induced fibrosis grade I/II in a dose-dependent fashion over a time period of 4 weeks. Thus, our study developed a humanized mouse model that will be instrumental to specifically examine leukemogenesis and therapeutic targets for AMKL blasts in future. IMPLICATIONS: TGFB1 supports fibrosis induction in a pediatric AMKL model generated with patient-derived MSCs. VISUAL OVERVIEW: http://mcr.aacrjournals.org/content/molcanres/18/10/1603/F1.large.jpg.

Glucocorticoids and selumetinib are highly synergistic in RAS pathway-mutated childhood acute lymphoblastic leukemia through upregulation of BIM

New drugs are needed for the treatment of relapsed acute lymphoblastic leukemia and preclinical evaluation of the MEK inhibitor, selumetinib, has shown that this drug has excellent activity in those leukemias with RAS pathway mutations. The proapoptotic protein, BIM is pivotal in the induction of cell death by both selumetinib and glucocorticoids, suggesting the potential for synergy. Thus, combination indices for dexamethasone and selumetinib were determined in RAS pathway-mutated acute lymphoblastic leukemia primagraft cells in vitro and were indicative of strong synergism (combination index <0.2; n=5). Associated pharmacodynamic assays were consistent with the hypothesis that the drug combination enhanced BIM upregulation over that achieved by a single drug alone. Dosing of dexamethasone and selumetinib singly and in combination in mice engrafted with primary-derived RAS pathway-mutated leukemia cells resulted in a marked reduction in spleen size which was significantly greater with the drug combination. Assessment of the central nervous system leukemia burden showed a significant reduction in the drug-treated mice, with no detectable leukemia in those treated with the drug combination. These data suggest that a selumetinib-dexamethasone combination may be highly effective in RAS pathway-mutated acute lymphoblastic leukemia. An international phase I/II clinical trial of dexamethasone and selumetinib (Seludex trial) is underway in children with multiply relapsed/refractory disease.

Targeting the thioredoxin system as a novel strategy against B-cell acute lymphoblastic leukemia

B‐cell precursor acute lymphoblastic leukemia (BCP‐ALL) is a genetically heterogeneous blood cancer characterized by abnormal expansion of immature B cells. Although intensive chemotherapy provides high cure rates in a majority of patients, subtypes harboring certain genetic lesions, such as MLL rearrangements or BCR‐ABL1 fusion, remain clinically challenging, necessitating a search for other therapeutic approaches. Herein, we aimed to validate antioxidant enzymes of the thioredoxin system as potential therapeutic targets in BCP‐ALL. We observed oxidative stress along with aberrant expression of the enzymes associated with the activity of thioredoxin antioxidant system in BCP‐ALL cells. Moreover, we found that auranofin and adenanthin, inhibitors of the thioredoxin system antioxidant enzymes, effectively kill BCP‐ALL cell lines and pediatric and adult BCP‐ALL primary cells, including primary cells cocultured with bone marrow‐derived stem cells. Furthermore, auranofin delayed the progression of leukemia in MLL‐rearranged patient‐derived xenograft model and prolonged the survival of leukemic NSG mice. Our results unveil the thioredoxin system as a novel target for BCP‐ALL therapy, and indicate that further studies assessing the anticancer efficacy of combinations of thioredoxin system inhibitors with conventional anti‐BCP‐ALL drugs should be continued.

Subtype-specific regulatory network rewiring in acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous disease caused by a variety of alterations in transcription factors, epigenetic regulators and signaling molecules. To determine how different mutant regulators establish AML subtype-specific transcriptional networks, we performed a comprehensive global analysis of cis-regulatory element activity and interaction, transcription factor occupancy and gene expression patterns in purified leukemic blast cells. Here, we focused on specific subgroups of subjects carrying mutations in genes encoding transcription factors (RUNX1, CEBPα), signaling molecules (FTL3-ITD, RAS) and the nuclear protein NPM1). Integrated analysis of these data demonstrates that each mutant regulator establishes a specific transcriptional and signaling network unrelated to that seen in normal cells, sustaining the expression of unique sets of genes required for AML growth and maintenance.

Sensitizing Ewing sarcoma to chemo- and radiotherapy by inhibition of the DNA-repair enzymes DNA protein kinase (DNA-PK) and poly-ADP-ribose polymerase (PARP) 1/2

Background

DNA-PK and PARP inhibitors sensitize cancer cells to chemo- and radiotherapy. ETS transcription factors (EWS-FLI1) have been described as biomarkers for PARP-inhibitor sensitivity. Sensitivity to single agent PARP inhibitors has so far been limited to homologous recombination repair (HRR) deficient tumors, exploiting synthetic lethality.

Results

In clonogenic assays, single agent rucaparib LD₅₀ values for continuously exposed cells were similar to those observed in HRR-defective cells (CAPAN-1 cell line, BRCA2 defective); however, both ES cell lines (TC-71, CADO-ES1) had functional HRR. In vivo rucaparib administration (10 mg/kg daily) showed no responses. In clonogenic assays, rucaparib enhanced temozolomide, camptothecin and radiation cytotoxicity, which was most profound for temozolomide (15–29 fold enhancement). NU7441 increased the cytotoxicity of etoposide, doxorubicin and radiation.

Materials and Methods

We assessed PARP1/2 (rucaparib) and DNA-PK (NU7441) inhibitors in Ewing sarcoma (ES) cell lines by performing growth inhibition and clonogenic assays. HRR was measured by RAD51 focus formation. Single agent rucaparib was assessed in an in vivo orthotopic model.

Conclusions

Single agent rucaparib ES sensitivity in vitro was not replicated in vivo. DNA-PK and PARP inhibitors are good chemo-/radiosensitizers in ES. The future of these inhibitors lies in their combination with chemo-/radiotherapy, which needs to be evaluated in clinical trials.

Inhibition of monocarboxyate transporter 1 by AZD3965 as a novel therapeutic approach for diffuse large B-cell lymphoma and Burkitt lymphoma

Inhibition of monocarboxylate transporter 1 has been proposed as a therapeutic approach to perturb lactate shuttling in tumor cells that lack monocarboxylate transporter 4. We examined the monocarboxylate transporter 1 inhibitor AZD3965, currently in phase I clinical studies, as a potential therapy for diffuse large B-cell lymphoma and Burkitt lymphoma. Whilst extensive monocarboxylate transporter 1 protein was found in 120 diffuse large B-cell lymphoma and 10 Burkitt lymphoma patients’ tumors, monocarboxylate transporter 4 protein expression was undetectable in 73% of the diffuse large B-cell lymphoma samples and undetectable or negligible in each Burkitt lymphoma sample. AZD3965 treatment led to a rapid accumulation of intracellular lactate in a panel of lymphoma cell lines with low monocarboxylate transporter 4 protein expression and potently inhibited their proliferation. Metabolic changes induced by AZD3965 in lymphoma cells were consistent with a feedback inhibition of glycolysis. A profound cytostatic response was also observed in vivo: daily oral AZD3965 treatment for 24 days inhibited CA46 Burkitt lymphoma growth by 99%. Continuous exposure of CA46 cells to AZD3965 for 7 weeks in vitro resulted in a greater dependency upon oxidative phosphorylation. Combining AZD3965 with an inhibitor of mitochondrial complex I (central to oxidative phosphorylation) induced significant lymphoma cell death in vitro and reduced CA46 disease burden in vivo. These data support clinical examination of AZD3965 in Burkitt lymphoma and diffuse large B-cell lymphoma patients with low tumor monocarboxylate transporter 4 expression and highlight the potential of combination strategies to optimally target the metabolic phenotype of tumors.

Nutritional plane of twin-bearing ewes alters fetal mammary gland biochemical composition and mTOR/MAPK pathway signaling

Identifying the biochemical changes and molecular pathways that regulate fetal mammary development in response to maternal nutrition is important for understanding the link between fetal programming of mammary development and future lactation performance. Although there are published studies regarding biochemical changes in the developing mammary gland, there are currently no data on molecular pathway involvement in regulating ruminant fetal mammary development. This study investigated changes in fetal mammary biochemical indices and mechanistic target of rapamycin (mTOR)/mitogen activated protein kinase (MAPK) signaling at d 100 and 140 of gestation in an ovine model of restricted maternal nutrition. Ewes were randomly allocated to ad libitum (A) or maintenance (M) nutritional regimens, under New Zealand pastoral grazing conditions, from d 21 to 140 of pregnancy. At d 100 and 140 of pregnancy, a subgroup of twin-bearing dams was euthanized, and whole fetal mammary glands (fiber, skin, fat, and ducts) were collected. Mammary glands of fetuses carried by M-fed dams were heavier at d 100 than those of fetuses carried by A-fed dams ( = 0.03), with no difference in the abundance of mTOR/MAPK signaling proteins observed. At d 140, mammary glands of fetuses carried by M-fed dams were lighter ( = 0.07) than fetuses carried by A-fed dams because of decreased hyperplasia ( = 0.04) and hypertrophy ( = 0.09) but had increased protein synthetic capacity ( = 0.02). Increased protein synthetic capacity was associated with increased abundance of MAPK pathway signaling proteins eukaryotic intiation factor 4E (eIF4E)/eIF4E and mTOR pathway signaling proteins eukaryotic initiation factor 4E-binding protein 1 (4E-BP1)/4E-BP1 and ribosomal protein S6 (RPS6)/RPS6 ( ≤ 0.05). Increased abundance of MAPK/mTOR pathway proteins is proposed to mediate increased protein synthetic capacity via ribosome biogenesis and the availability of factors required to initiate protein translation. The primary regulator of 4E-BP1 phosphorylation at Ser65 and RPS6 at Ser235/236 is the activated form of mTOR: mTOR. To study potential tissue-specific mTOR, mTOR abundance mammary glands, separated into parenchyma and fat pad, were collected from d 140 fetuses carried by dams fed a lucerne-based pellet diet formulated to meet 100% of the NRC-recommended maintenance requirements. Results showed that the abundance of mTOR was primarily localized to the fat pad, indicating that the fat pad plays a potential role in regulating development of the fetal mammary gland.

Transgenerational effects of caloric restriction on appetite: a meta-analysis

Maternal undernutrition can result in significant alterations to the post-natal offspring phenotype, including body size and behaviour. For example, maternal food restriction has been implicated in offspring hyperphagia, potentially causing increased weight gain and fat accumulation. This could result in obesity and other adverse long-term health effects in offspring. We investigated the link between maternal caloric restriction during gestation and offspring appetite by conducting the first meta-analysis on this topic using experimental data from mammalian laboratory models (i.e. rats and mice). We collected 89 effect sizes from 35 studies, together with relevant moderators. Our analysis revealed weak and statistically non-significant overall effect on offspring's appetite. However, we found that lower protein content of restricted diets is associated with higher food intake in female offspring. Importantly, we show that a main source of variation among studies arises from whether, and how, food intake was adjusted for body mass. This probably explains many of the contradictory results in the field. Based on our results, we recommend using allometric scaling of food intake to body mass in future studies.

Development of a preclinical orthotopic xenograft model of ewing sarcoma and other human malignant bone disease using advanced in vivo imaging

Ewing sarcoma and osteosarcoma represent the two most common primary bone tumours in childhood and adolescence, with bone metastases being the most adverse prognostic factor. In prostate cancer, osseous metastasis poses a major clinical challenge. We developed a preclinical orthotopic model of Ewing sarcoma, reflecting the biology of the tumour-bone interactions in human disease and allowing in vivo monitoring of disease progression, and compared this with models of osteosarcoma and prostate carcinoma. Human tumour cell lines were transplanted into non-obese diabetic/severe combined immunodeficient (NSG) and Rag2^−/−/γc^−/− mice by intrafemoral injection. For Ewing sarcoma, minimal cell numbers (1000–5000) injected in small volumes were able to induce orthotopic tumour growth. Tumour progression was studied using positron emission tomography, computed tomography, magnetic resonance imaging and bioluminescent imaging. Tumours and their interactions with bones were examined by histology. Each tumour induced bone destruction and outgrowth of extramedullary tumour masses, together with characteristic changes in bone that were well visualised by computed tomography, which correlated with post-mortem histology. Ewing sarcoma and, to a lesser extent, osteosarcoma cells induced prominent reactive new bone formation. Osteosarcoma cells produced osteoid and mineralised “malignant” bone within the tumour mass itself. Injection of prostate carcinoma cells led to osteoclast-driven osteolytic lesions. Bioluminescent imaging of Ewing sarcoma xenografts allowed easy and rapid monitoring of tumour growth and detection of tumour dissemination to lungs, liver and bone. Magnetic resonance imaging proved useful for monitoring soft tissue tumour growth and volume. Positron emission tomography proved to be of limited use in this model. Overall, we have developed an orthotopic in vivo model for Ewing sarcoma and other primary and secondary human bone malignancies, which resemble the human disease. We have shown the utility of small animal bioimaging for tracking disease progression, making this model a useful assay for preclinical drug testing.

Plasma metabolite concentrations and hepatic enzyme activities in pregnant Romney ewes with restricted feeding

Plasma metabolite concentrations and activities of enzymes related to energy metabolism in plasma, peripheral leukocytes and liver of pregnant Romney ewes with restricted feeding were measured to assess those metabolites and enzymes as indicators for evaluating metabolic conditions in the ewes. The body weights and plasma lactate concentrations of the low-feeding ewes (about 1.0 times maintenance) were significantly lower than those of the high-feeding ewes (about 1.5 times maintenance). There were no significant differences in plasma protein, glucose, triglyceride, cholesterol, pyruvate and immunoreactive insulin concentrations and plasma and leukocyte enzyme activities between both groups. Hepatic malate dehydrogenase activities were significantly higher and hexokinase activities were significantly lower in the low-feeding ewes than in the high-feeding ewes. Restricted feeding could maintain pregnancy and some plasma metabolites and peripheral leukocyte enzymes may be useful indicators for evaluating metabolic changes in ewes.

Changes in metabolite, energy metabolism related enzyme activities and peripheral blood mononuclear cell (PBMC) populations in beef heifers with two differing liveweight change profiles in New Zealand

Metabolite and immunoreactive insulin (IRI) concentrations, energy metabolism related enzymes activities and peripheral blood mononuclear cell (PBMC) populations were measured in blood of pregnant Angus heifers with differing liveweight change profiles (gaining or losing), in New Zealand to investigate the meanings of those parameters in the restricted feeding beef heifers. Beef heifers losing liveweight (-412 g/day) showed significantly lower concentrations of plasma IRI, and higher concentrations of plasma free fatty acid (FFA) than heifers gaining liveweight (483 g/day). The cytosolic and mitochondrial malate dehydrogenase (MDH) activities and MDH/lactate dehydrogenase (M/L) ratio in leukocytes of the liveweight losing heifers were significantly higher than those the liveweight gaining heifers. Percentages of cluster of differentiation (CD) 3 positive cells and natural killer (NK) cells in PBMC decreased significantly in the liveweight losing heifers compared to those in the liveweight gaining heifers. Plasma IRI and FFA concentrations, leukocyte cytosolic and mitochondrial MDH activities and CD3 positive and NK cell populations may be useful markers to evaluate metabolic conditions and immunity in the restricted feeding beef heifers.

Comparison of Plasma Metabolite Concentrations and Enzyme Activities in Beef Cattle Raised by Different Feeding Systems in Korea, Japan and New Zealand

Concentrations of metabolites and immunoreactive insulin (IRI) and activities of enzymes related to energy metabolism were measured in plasma of Korean and Japanese beef cattle, which were raised by the indoor feeding system programmed to feed larger amount of roughage in their growing periods and larger amount of concentrate diet in their finishing periods (Japanese feeding system), and grazing New Zealand beef cattle. By the Japanese beef grading system, Korean and Japanese beef cattle showed high beef quality score, average grade 3.3 and 3.6, respectively. The plasma free fatty acid and lactate concentrations and lactate dehydrogenase (LDH), malate dehydrogenase (MDH) and aspartate aminotransferase (AST) activities in Korean beef cattle were significantly higher than those in Japanese beef cattle. The plasma lactate concentration in Korean beef cattle was 8.40 mmol/l, which was similar to the values observed in lactic acidosis. The higher activities of plasma LDH, MDH and AST may indicate slight liver damage by slightly acidotic conditions in Korean beef cattle. New Zealand beef cattle fed on pasture which they harvest by grazing showed significantly lower plasma glucose, cholesterol, lactate and IRI concentrations and enzyme activities than those in Korean and Japanese beef cattle fed on larger amount of concentrate diets. Plasma metabolite concentrations and energy metabolism-related enzyme activities may be good indicators for evaluating metabolic conditions of beef cattle raised by different feeding systems.

Diagnostic and prognostic significance of a t(1;19)(q10;p10) in patients (pts) with low-grade oligodendroglioma and astrocytoma: NCCTG 94–72–53

1505

Background: Combined deletion of chromosomes 1p and 19q is associated with improved prognosis in pts with anaplastic oligodendroglioma. We recently discovered that the combined deletion is mediated by a chromosome 1;19 translocation: t(1;19)(q10;p10). The prognostic significance of this alteration in pts with low-grade gliomas is not known. Methods: Paraffin-embedded tumor tissue was obtained from 134 pts enrolled in two NCCTG trials for newly-diagnosed low-grade glioma: 86–72–51: a randomized phase III trial of 50.4 Gy vs 64.8 Gy radiation therapy (RT) and 93–72–02: a phase II trial of PCV for 6 cycles followed by RT. Interphase fusion of a CEP1 probe and a BAC contig probe for 19p12 was used to detect the 1;19 translocation. Analysis of 1p and 19q deletions had been previously performed by FISH. Kaplan-Meier distributions of overall survival (OS) and progression-free survival (PFS) for pts whose tumors did or did not exhibit CEP1/19p12 fusion were compared using the Wilcoxon test. Results: Of 134 pts, CEP1/19p12 fusion testing was informative for 92. CEP1/19p12 fusion prevalence was 55% among 42 oligodendrogliomas, 47% among 30 mixed oligoastrocytomas, and 5% among 20 astrocytomas. 91% of gliomas with and 11% without 1p/19q deletion had CEP1/19p12 fusion (p<0.0001, chi-square test). The frequency of the t(1;19) by tumor histology, as well as median and 5-year progression-free and overall survival are provided in the table . Conclusions: Our results strongly suggest that a t(1;19)(q10;p10) mediates the combined deletion of 1p and 19q in human gliomas. Like combined 1p and 19q deletion, the 1;19 translocation is associated with superior progression-free and overall survival in low-grade oligodendroglioma patients. FISH analysis of the t(1;19) will likely be a more sensitive and specific means to assess 1p and 19q status in patients with gliomas. (Supported in part by CA85799, CA108961 and NCCTG grants CA25224 and CA114740)

[Table: see text]

No significant financial relationships to disclose.

Targeting polymerised liposome vaccine carriers to intestinal M cells

Due to their transcytotic capability, intestinal M cells may represent an efficient potential route for oral vaccine delivery. We previously demonstrated that the lectin Ulex europaeus agglutinin 1 (UEA1, specific for alpha-L-fucose residues) selectively binds to mouse Peyer's patch M cells and targets 0.5 microm polystyrene microparticles to these cells. Using a gut loop model we now demonstrate that covalently-membrane-bound UEA1 similarly targets polymerised liposomes (Orasomes, approximately 200 nm diameter), potential biocompatable oral vaccine delivery vehicles, to mouse M cells. Targeting was inhibited by alpha-L-fucose while the co-entrapped adjuvant, monophosphoryl Lipid A (MPL), failed to exert any detrimental effect on UEA1-mediated M cell targeting. Lectin-mediated M cell targeting may thus permit the efficacy of mucosal vaccines to be enhanced if cellular relationship between particle binding and immune outcome can be established.