Characterization of Primary Esophageal/Gastro-esophageal Junction Cancer Xenograft Models and their Effectiveness in Studying Chemosensitivity

Primary esophageal (E) and gastro-esophageal junction (GEJ) cancer xenografts have the potential to become useful pre-clinical models of disease. In this study, we determined that p16 negative tumors that have not been exposed to neo-adjuvant chemo-radiation have higher engraftment chances. Morphological features and expression of certain molecular markers (p53, p16, Ki-67, EGFR, Her-2/neu) suggest that no major changes occur between primary tumors and xenografts or between early passage and late passage xenografts. Global gene expression data supported these results but revealed that approximately 2000 genes differed significantly between passage one xenografts and human tumors. Most of these genes, however, might coincide with stromal signals present in patient tumors but absent in xenografts. Primary E/GEJ cancer xenografts also showed a wide range of chemosensitivities to cisplatin-paclitaxel treatment, confirming the usefulness of these models in drug testing. These models also revealed potential ways to interrogate tumor initiating cell (TIC) dynamics after chemotherapy.MAS

Midazolam dose correlates with abnormal hippocampal growth and neurodevelopmental outcome in preterm infants.

OBJECTIVE: Very preterm-born neonates (24-32 weeks of gestation) are exposed to stressful and painful procedures during neonatal intensive care. Analgesic and sedation therapies are essential, and opiates and benzodiazepines are commonly used. These medications may negatively impact brain development. The hippocampus may be especially vulnerable to the effects of pain and analgesic and/or sedative therapies and contribute to adverse outcomes. The effect of invasive procedures and analgesic-sedative exposure on hippocampal growth was assessed, as was that of hippocampal growth on neurodevelopmental outcome. METHODS: A total of 138 neonates (51% male, median gestational age = 27.7 weeks) underwent magnetic resonance imaging and diffusion tensor imaging (DTI) scans, early in life (postmenstrual age [PMA] = 32.3 weeks) and at term-equivalent age (PMA = 40.2 weeks). Volumes and DTI measures of axial diffusivity, radial diffusivity, and mean diffusivity (MD) were obtained from the hippocampus. Cognitive, language, and motor abilities were assessed using the Bayley Scales of Infant Development-III at 18.7 months median corrected age. Models testing the association of invasive procedures with hippocampal volumes and DTI measures accounted for birth gestational age, sex, PMA, dose of analgesics/sedatives (fentanyl, morphine, midazolam), mechanical ventilation, hypotension, and surgeries. RESULTS: Total midazolam dose predicted decreased hippocampal volumes (β = -1.8, p \u3c 0.001) and increased MD (β = 0.002, p = 0.02), whereas invasive procedures did not (β = 0, p \u3e 0.5 each). Lower cognitive scores were associated with hippocampal growth (β = -0.31, p = 0.003), midazolam dose (β = -0.27, p = 0.03), and surgery (β = -8.32, p = 0.04). INTERPRETATION: Midazolam exposure was associated with macro- and microstructural alterations in hippocampal development and poorer outcomes consistent with hippocampal dysmaturation. Use of midazolam in preterm neonates, particularly those not undergoing surgery, is cautioned

Correction: Hedgehog inhibition mediates radiation sensitivity in mouse xenograft models of human esophageal adenocarcinoma

[This corrects the article DOI: 10.1371/journal.pone.0194809.]

Primary esophageal and gastro-esophageal junction cancer xenograft models:Clinicopathological features and engraftment

<p><b>A–C.</b> Voltage recordings of locomotor-related drive obtained from embryonic slow (ES) fibres of control (<b>A</b>), DETA-NO raised (<b>B</b>) and L-NAME raised (<b>C</b>) fish at 2 days post fertilisation (dpf). <b>D–F</b>. Mean end plate potential (EPP) amplitude (<b>D</b>), rise time (<b>E</b>) and decay time (<b>F</b>) measured during episodes of fictive swimming. Data in <b>D-F</b> are represented as mean ± SEM. *** p<0.001.</p

Appropriateness of using patient-derived xenograft models for pharmacologic evaluation of novel therapies for esophageal/gastro-esophageal junction cancers.

The high morbidity and mortality of patients with esophageal (E) and gastro-esophageal junction (GEJ) cancers, warrants new pre-clinical models for drug testing. The utility of primary tumor xenografts (PTXGs) as pre-clinical models was assessed. Clinicopathological, immunohistochemical markers (p53, p16, Ki-67, Her-2/neu and EGFR), and global mRNA abundance profiles were evaluated to determine selection biases of samples implanted or engrafted, compared with the underlying population. Nine primary E/GEJ adenocarcinoma xenograft lines were further characterized for the spectrum and stability of gene/protein expression over passages. Seven primary esophageal adenocarcinoma xenograft lines were treated with individual or combination chemotherapy. Tumors that were implanted (n=55) in NOD/SCID mice had features suggestive of more aggressive biology than tumors that were never implanted (n=32). Of those implanted, 21/55 engrafted; engraftment was associated with poorly differentiated tumors (p=0.04) and older patients (p=0.01). Expression of immunohistochemical markers were similar between patient sample and corresponding xenograft. mRNA differences observed between patient tumors and first passage xenografts were largely due to loss of human stroma in xenografts. mRNA patterns of early vs late passage xenografts and of small vs large tumors of the same passage were similar. Complete resistance was present in 2/7 xenografts while the remaining tumors showed varying degrees of sensitivity, that remained constant across passages. Because of their ability to recapitulate primary tumor characteristics during engraftment and across serial passaging, PTXGs can be useful clinical systems for assessment of drug sensitivity of human E/GEJ cancers

Appropriateness of using patient-derived xenograft models for pharmacologic evaluation of novel therapies for esophageal/gastro-esophageal junction cancers

The high morbidity and mortality of patients with esophageal (E) and gastro-esophageal junction (GEJ) cancers, warrants new pre-clinical models for drug testing. The utility of primary tumor xenografts (PTXGs) as pre-clinical models was assessed. Clinicopathological, immunohistochemical markers (p53, p16, Ki-67, Her-2/neu and EGFR), and global mRNA abundance profiles were evaluated to determine selection biases of samples implanted or engrafted, compared with the underlying population. Nine primary E/GEJ adenocarcinoma xenograft lines were further characterized for the spectrum and stability of gene/protein expression over passages. Seven primary esophageal adenocarcinoma xenograft lines were treated with individual or combination chemotherapy. Tumors that were implanted (n=55) in NOD/SCID mice had features suggestive of more aggressive biology than tumors that were never implanted (n=32). Of those implanted, 21/55 engrafted; engraftment was associated with poorly differentiated tumors (p=0.04) and older patients (p=0.01). Expression of immunohistochemical markers were similar between patient sample and corresponding xenograft. mRNA differences observed between patient tumors and first passage xenografts were largely due to loss of human stroma in xenografts. mRNA patterns of early vs late passage xenografts and of small vs large tumors of the same passage were similar. Complete resistance was present in 2/7 xenografts while the remaining tumors showed varying degrees of sensitivity, that remained constant across passages. Because of their ability to recapitulate primary tumor characteristics during engraftment and across serial passaging, PTXGs can be useful clinical systems for assessment of drug sensitivity of human E/GEJ cancers

Hedgehog inhibition mediates radiation sensitivity in mouse xenograft models of human esophageal adenocarcinoma

<div><p>Background</p><p>The Hedgehog (Hh) signaling pathway is active in esophageal adenocarcinoma (EAC). We used a patient-derived murine xenograft (PDX) model of EAC to evaluate tumour response to conventional treatment with radiation/chemoradiation with or without Hh inhibition. Our goal was to determine the potential radioresistance effects of Hh signaling and radiosensitization by Hh inhibitors.</p><p>Methods</p><p>PDX models were treated with radiation, chemotherapy or combined chemoradiation. Tumour response was measured by growth delay. Hh transcript levels (qRT-PCR) were compared among frozen tumours from treated and control mice. 5E1, a monoclonal SHH antibody, or LDE225, a clinical SMO inhibitor (Novartis®) inhibited Hh signaling.</p><p>Results</p><p>Precision irradiation significantly delayed xenograft tumour growth in all 7 PDX models. Combined chemoradiation further delayed growth relative to either modality alone in three of six PDX models. Following irradiation, two of three PDX models demonstrated sustained up-regulation of Hh transcripts. Combined LDE225 and radiation, and 5E1 alone delayed growth relative to either treatment alone in a Hh-responsive PDX model, but not in a non-responsive model.</p><p>Conclusion</p><p>Hh signaling mediates the radiation response in some EAC PDX models, and inhibition of this pathway may augment the efficacy of radiation in tumours that are Hh dependent.</p></div

Baseline expression of Hedgehog transcripts in untreated EAC tumours from six PDX models.

<p>“Human” represents the patient-derived epithelium. “Mouse” represents the host stroma. Transcript levels are normalized to the highest expressed gene per species per model.</p