Quantifying DNA damage following light sheet and confocal imaging of the mammalian embryo.

Embryo quality assessment by optical imaging is increasing in popularity. Among available optical techniques, light sheet microscopy has emerged as a superior alternative to confocal microscopy due to its geometry, enabling faster image acquisition with reduced photodamage to the sample. However, previous assessments of photodamage induced by imaging may have failed to measure more subtle impacts.

UVA Hyperspectral Light-Sheet Microscopy for Volumetric Metabolic Imaging: Application to Preimplantation Embryo Development.

Cellular metabolism is a key regulator of energetics, cell growth, regeneration, and homeostasis. Spatially mapping the heterogeneity of cellular metabolic activity is of great importance for unraveling the overall cell and tissue health. In this regard, imaging the endogenous metabolic cofactors, nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) and flavin adenine dinucleotide (FAD), with subcellular resolution and in a noninvasive manner would be useful to determine tissue and cell viability in a clinical environment, but practical use is limited by current imaging techniques.

Investigation of refractive index dynamics during embryo development using off-axis digital holographic microscopy.

Embryo quality is a crucial factor affecting live birth outcomes. However, an accurate diagnostic for embryo quality remains elusive in the fertilization clinic. Determining physical parameters of the embryo may offer key information for this purpose.

Third harmonic imaging contrast from tubular structures in the presence of index discontinuity.

Accurate interpretation of third harmonic generation (THG) microscopy images in terms of sample optical properties and microstructure is generally hampered by the presence of excitation field distortions resulting from sample heterogeneity. Numerical methods that account for these artifacts need to be established. In this work, we experimentally and numerically analyze the THG contrast obtained from stretched hollow glass pipettes embedded in different liquids.

EGFR tyrosine kinase inhibition radiosensitizes and induces apoptosis in malignant glioma and childhood ependymoma xenografts.

Malignant gliomas and childhood ependymomas have a high rate of treatment failure. Epidermal growth factor receptor (EGFR) activation has been implicated in the tumorigenesis and radioresistance of many cancers, including brain tumors. Therefore, combining EGFR targeting with irradiation is a potentially attractive therapeutic option.

Induction of glutathione synthesis explains pharmacodynamics of high-dose busulfan in mice and highlights putative mechanisms of drug interaction.

Busulfan is an example of a drug eliminated through glutathione S-transferase (GST)-catalyzed conjugation with reduced glutathione (GSH). We studied the pharmacokinetics and toxicity of busulfan in C57BL6 mice in correlation with liver GST activity and GSH synthesis by accurate determination of precursors, namely, gamma-glutamyl-cysteine and cysteine. A significantly lower incidence of acute toxicity was observed in mice receiving busulfan 16.

Pleiotrophin, a candidate gene for poor tumor vasculature and in vivo neuroblastoma sensitivity to irinotecan.

In vivo neuroblastoma (NB) xenograft model, resistant to the DNA-topoisomerase I inhibitor irinotecan (CPT-11), has been established to study resistance mechanisms acquired in a therapeutic setting. Common mechanisms of resistance were not involved in this resistance. Thus, we compared the gene expression profiles of sensitive, resistant, and reverted tumors using cDNA expression arrays.

Liquid chromatography-tandem mass spectrometry assay of reduced and oxidized glutathione and main precursors in mice liver.

A liquid chromatography/tandem mass spectrometry assay of glutathione (GSH), glutathione disulfide (GSSG) and of precursors (gamma-glutamyl-cysteine, cysteinyl-glycine, cysteine, cystine, homocysteine and homocystine) was developed to study glutathione synthesis in mice liver. After iodoacetic acid derivatization, the analytes were analyzed using reversed-phase gradient HPLC and detected using multiple reaction monitoring. Linear calibrations were performed over the concentrations range of 100-10,000 ng/mL for the thiol-containing precursors and extended up to 100,000 ng/mL for GSH and GSSG.

Expression of p53, or targeting towards EGFR, enhances the oncolytic potency of conditionally replicative adenovirus against neuroblastoma.

Background: Advanced stage and relapsing neuroblastoma (NB) has a poor prognosis with frequent treatment failures, warranting new treatment options and enhanced local tumor control. Treatment with conditionally replicative adenoviruses (CRAds) has shown effectiveness in various preclinical cancer models, but has not yet been evaluated for local control of NB. Here, we tested the efficacy of the CRAd AdDelta24 and of two AdDelta24 derivatives against NB.

Negative preclinical results with stealth nanospheres-encapsulated Doxorubicin in an orthotopic murine brain tumor model.

Previous results have shown that PEG-coated poly(hexadecylcyanoacrylate) (PEG-PHDCA) nanospheres displayed a significant accumulation within an orthotopic 9L gliosarcoma model, after i.v. administration to rats.

Oncolytic activity of p53-expressing conditionally replicative adenovirus AdDelta24-p53 against human malignant glioma.

Prognosis of malignant glioma is poor, and results of treatment remain mediocre. Conditionally replicative adenoviruses hold promise as alternative anticancer agents for the treatment of malignant glioma. Here, we evaluated the conditionally replicative adenovirus AdDelta24 and its recently developed derivative AdDelta24-p53, which expresses functional p53 tumor suppressor protein while replicating in cancer cells, for treatment of malignant glioma.

No topoisomerase I alteration in a neuroblastoma model with in vivo acquired resistance to irinotecan.

CPT-11 (irinotecan) is a DNA-topoisomerase I inhibitor with preclinical activity against neuroblastoma (NB) xenografts. The aim was to establish in vivo an NB xenograft resistant to CPT-11 in order to study the resistance mechanisms acquired in a therapeutic setting. IGR-NB8 is an immature NB xenograft with MYCN amplification and 1p deletion, which is sensitive to CPT-11.

In vivo treatment with CPT-11 leads to differentiation of neuroblastoma xenografts and topoisomerase I alterations.

Topoisomerase I inhibitors, such as CPT-11, are potent anticancer drugs against neuroblastoma (NB). Differentiating agents, such as retinoids, improve the survival of children with metastatic NB. To characterize the biological effects associated with exposure to CPT-11 in vivo, athymic mice bearing a human NB xenograft, named IGR-NB8 and characterized as an immature NB with poor prognostic markers, were treated with CPT-11.

High level of stabilized angiostatin mediated by adenovirus delivery does not impair the growth of human neuroblastoma xenografts.

Human neuroblastoma (NB) is a highly heterogeneous childhood cancer secreting a high level of vascular endothelial growth factor (VEGF). Its vascularization has been clearly correlated with metastatic progression and poor outcome. Thus, molecules that target the vascular endothelium are regarded as new therapeutics of clinical interest.

Potentiation of radiation therapy by the oncolytic adenovirus dl1520 (ONYX-015) in human malignant glioma xenografts.

In spite of aggressive surgery, irradiation and/or chemotherapy, treatment of malignant gliomas remains a major challenge in adults and children due to high treatment failure. We have demonstrated significant cell lysis and antitumour activity of the E1B-55 kDa-gene-deleted adenovirus ONYX-015 (dl1520, CI-1042; ONYX Pharmaceuticals) in subcutaneous human malignant glioma xenografts deriving from primary tumours. Here, we show the combined efficacy of this oncolytic therapy with radiation therapy.

In vivo antitumor activity of S16020, a topoisomerase II inhibitor, and doxorubicin against human brain tumor xenografts.

New active drugs are needed for the treatment of primary brain tumors in both children and adults. S16020 is a cytotoxic olivacine derivative that inhibits topoisomerase II. The aim of the study was to determine its antitumor activity in athymic mice bearing subcutaneous medulloblastoma (IGRM33, 34, 57) and glioblastoma (IGRG88, 93, 121) xenografts treated at an advanced stage of tumor growth in comparison with that of doxorubicin.

Poly(ethylene glycol)-coated hexadecylcyanoacrylate nanospheres display a combined effect for brain tumor targeting.

The aim of the present study was to evaluate the tumor accumulation of radiolabeled long-circulating poly(ethylene glycol) (PEG)-coated hexadecylcyanoacrylate nanospheres and non-PEG-coated hexadecylcyanoacrylate nanospheres (used as control), after intravenous injection in Fischer rats bearing intracerebrally well established 9L gliosarcoma. Both types of nanospheres showed an accumulation with a retention effect in the 9L tumor. However, long-circulating nanospheres concentrated 3.

Oncolytic activity of the E1B-55 kDa-deleted adenovirus ONYX-015 is independent of cellular p53 status in human malignant glioma xenografts.

Treatment of malignant gliomas remains a major challenge in adults and children because of high treatment failure. The E1B 55 kDa-gene deleted adenovirus, ONYX-015 (ONYX Pharmaceuticals), was demonstrated to replicate selectively in and lyse tumor cells. Currently ongoing clinical trials of ONYX-015 in head and neck tumors are promising.

Busulphan is active against neuroblastoma and medulloblastoma xenografts in athymic mice at clinically achievable plasma drug concentrations.

High-dose busulphan-containing chemotherapy regimens have shown high response rates in children with relapsed or refractory neuroblastoma, Ewing's sarcoma and medulloblastoma. However, the anti-tumour activity of busulfan as a single agent remains to be defined, and this was evaluated in athymic mice bearing advanced stage subcutaneous paediatric solid tumour xenografts. Because busulphan is highly insoluble in water, the use of several vehicles for enteral and parenteral administration was first investigated in terms of pharmacokinetics and toxicity.

Preclinical development of camptothecin derivatives and clinical trials in pediatric oncology.

Although the prognosis of childhood cancers has dramatically improved over the last three decades, new active drugs are needed. Camptothecins represent a very attractive new class of anticancer drugs to develop in paediatric oncology. The preclinical and clinical development of two of these DNA-topoisomerase I inhibitors, i.

Activity of fotemustine in medulloblastoma and malignant glioma xenografts in relation to O6-alkylguanine-DNA alkyltransferase and alkylpurine-DNA N-glycosylase activity.

Fotemustine is a chloroethylnitrosourea with antitumor activity in disseminated melanoma and adult primary brain tumors. Because new drugs are required for the treatment of medulloblastoma in children, we evaluated the preclinical antitumor activity of fotemustine in four s.c.

DNA-topoisomerase I, a new target for the treatment of neuroblastoma.

DNA-topoisomerase I is the nuclear target of new anticancer drugs, namely camptothecin and its derivatives. In order to establish the rational basis for their clinical development in paediatric oncology, the antitumour activity of irinotecan (CPT-11) and topotecan, two camptothecin water-soluble derivatives, was studied in nude mice bearing neuroblastoma xenografts. The panel was composed of 4 previously established subcutaneous xenograft lines (IGR-N835, IGR-N91, IGR-NB3, IGR-NB8) that exhibited the common biological markers of poor prognosis in children (MYCN amplification, 1p deletion, paradiploidy and/or MDR1 overexpression).

Potent therapeutic activity of irinotecan (CPT-11) and its schedule dependency in medulloblastoma xenografts in nude mice.

The anti-tumor activity of irinotecan (CPT-11), a DNA-topoisomerase 1 inhibitor, was evaluated in 5 advanced stage subcutaneous medulloblastoma xenografts in nude mice, using different schedules of administration. With a 5-day schedule, the highest i.v.

Therapeutic activity of CPT-11, a DNA-topoisomerase I inhibitor, against peripheral primitive neuroectodermal tumour and neuroblastoma xenografts.

The anti-tumour activity of CPT-11, a topoisomerase I inhibitor, was evaluated in four human neural-crest-derived paediatric tumour xenografts; one peripheral primitive neuroectodermal tumour (pPNET) (SK-N-MC) and three neuroblastomas. Two models, SK-N-MC and IGR-N835, were established in athymic mice from a previously established in vitro cell line. Two new neuroblastoma xenograft models, IGR-NB3 and IGR-NB8, were derived from previously untreated non-metastatic neuroblastomas.

Tumorigenicity of cerebellar primitive neuro-ectodermal tumors in athymic mice correlates with poor prognosis in children.

The histogenesis of medulloblastoma, also described as a cerebellar primitive neuro-ectodermal tumor (PNET), remains controversial and unresolved. In addition, genetic markers which characterize cerebellar PNETs with poor prognosis in children have not been identified. Since xenografts can be valuable tools for better understanding the genetic events involved in cerebellar PNETs, small fragments of tumor samples from 17 children with newly diagnosed cerebellar PNETs were transplanted s.