Veränderungen der urethelialen Proteinexpression im Rahmen chronischer Strahleneffekte an der Harnblase : tierexperimentelle Untersuchungen

bei der Autori

Veränderungen der urethelialen Proteinexpression im Rahmen chronischer Strahleneffekte an der Harnblase : tierexperimentelle Untersuchungen

bei der Autori

Veränderungen der urethelialen Proteinexpression im Rahmen chronischer Strahleneffekte an der Harnblase : tierexperimentelle Untersuchungen

bei der Autori

BAY 87–2243, a novel inhibitor of hypoxia-induced gene activation, improves local tumor control after fractionated irradiation in a schedule-dependent manner in head and neck human xenografts

BACKGROUND: The transcription factor hypoxia-inducible factor-1 (HIF-1) pathway plays an important role in tumor response to cytotoxic treatments. We investigated the effects of a novel small molecule inhibitor of mitochondrial complex I and hypoxia-induced HIF-1 activity BAY-87-2243, on tumor microenvironment and response of human squamous cell carcinoma (hSCC) to clinically relevant fractionated radiotherapy (RT) with and without concomitant chemotherapy. METHODS: When UT-SCC-5 hSCC xenografts in nude mice reached 6 mm in diameter BAY-87-2243 or carrier was administered before and/or during RT or radiochemotherapy with concomitant cisplatin (RCT). Local tumor control was evaluated 150 days after irradiation and the doses to control 50% of tumors (TCD(50)) were compared between treatment arms. Tumors were excised at different time points during BAY-87-2243 or carrier treatment for western blot and immunohistological investigations. RESULTS: BAY-87-2243 markedly decreased nuclear HIF-1α expression and pimonidazole hypoxic fraction already after 3 days of drug treatment. BAY-87-2243 prior to RT significantly reduced TCD(50) from 123 to 100 Gy (p=0.037). Additional BAY-87-2243 application during RT did not decrease TCD(50). BAY-87-2243 before and during radiochemotherapy did not improve local tumor control. CONCLUSIONS: Pronounced reduction of tumor hypoxia by application of BAY-87-2243 prior to RT improved local tumor control. The results demonstrate that radiosensitizing effect importantly depends on treatment schedule. The data support further investigations of HIF-1 pathway inhibitors for radiotherapy and of predictive tests to select patients who will benefit from this combined treatment

An optimized small animal tumour model for experimentation with low energy protons

<div><p>Background</p><p>The long-term aim of developing laser based particle acceleration towards clinical application requires not only substantial technological progress, but also the radiobiological characterization of the resulting ultra-short and ultra-intensive particle beam pulses. After comprehensive cell studies a mouse ear tumour model was established allowing for the penetration of low energy protons (~20 MeV) currently available at laser driven accelerators. The model was successfully applied for a first tumour growth delay study with laser driven electrons, whereby the need of improvements crop out.</p><p>Methods</p><p>To optimise the mouse ear tumour model with respect to a stable, high take rate and a lower number of secondary tumours, Matrigel was introduced for tumour cell injection. Different concentrations of two human tumour cell lines (FaDu, LN229) and Matrigel were evaluated for stable tumour growth and fulfilling the allocation criteria for irradiation experiments. The originally applied cell injection with PBS was performed for comparison and to assess the long-term stability of the model. Finally, the optimum suspension of cells and Matrigel was applied to determine applicable dose ranges for tumour growth delay studies by 200 kV X-ray irradiation.</p><p>Results</p><p>Both human tumour models showed a high take rate and exponential tumour growth starting at a volume of ~10 mm³. As disclosed by immunofluorescence analysis these small tumours already interact with the surrounding tissue and activate endothelial cells to form vessels. The formation of delimited, solid tumours at irradiation size was shown by standard H&E staining and a realistic dose range for inducing tumour growth delay without permanent tumour control was obtained for both tumour entities.</p><p>Conclusion</p><p>The already established mouse ear tumour model was successfully upgraded now providing stable tumour growth with high take rate for two tumour entities (HNSCC, glioblastoma) that are of interest for future irradiation experiments at experimental accelerators.</p></div

GD_V5 values for the two tumour models.

<p>For LN229 treated with a dose of 3.5 Gy the value was not calculated since the corresponding time values are not significantly different from control. Dose errors include systematic and measuring uncertainties of film calibration and dose measurement; errors of the individual GD_V5 values were calculated by error propagation.</p

Tumour growth curves on mouse ear.

<p>Tumour growth curves obtained for (a) FaDu and (b) LN229 for the different cell/MG suspensions. The measured tumour volumes (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0177428#pone.0177428.s001" target="_blank">S1 Table</a> for FaDu and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0177428#pone.0177428.s002" target="_blank">S2 Table</a> for LN229) in dependence on time were averaged for all animals of the corresponding group with the number of animals per group given in brackets. Grey dotted horizontal lines indicate the starting volumes of 5 mm³ and 10 mm³ for the exponential tumour growth of FaDu and LN229, respectively.</p

Histology of the small mouse ear tumours.

<p>Exemplary tumour sections used to characterize the tumour micromileu for tumour sizes of 1–2 mm (1^st line), ≤ 2.5 mm (2^nd line) and at treatment size of 3–4 mm (3^rd line) for HNSCC FaDu and GBM LN229. The tumour appearance within the surrounding normal tissue was confirmed by classical H&E staining (a-c, g-i) and is shown in 50x magnification, except the inset of Fig 5a, where a magnification of 400x was applied. The analysis of tumour histology takes place by immunofluorescence staining of perfused areas (blue, Hoechst 33342), of small vessels (red, CD31) and of hypoxic regions (green, pimonidazole). Due to technical reasons sections of two different tumours are shown in Fig 5b and 5e, whereas the stained sections of all other pairs were taken from the same tumour.</p