In vitro and in vivo evaluation of the radiosensitizing effect of a selective FGFR inhibitor (JNJ-42756493) for rectal cancer.

Background: We examined the anti-tumor effect and radiosensitizing potential of a small molecule inhibitor of fibroblast growth factor receptor (FGFR) in colorectal cancer (CRC) in vitro and in vivo.

Methods: Effects of in vitro drug treatment on cell survival, proliferation, FGFR signaling, cell cycle distribution, apoptosis and radiosensitivity were assessed using various CRC cell lines with FGFR wild type (Caco2 and HCA7) and FGFR2 amplification (HCT116, NCI-H716). In vivo tumor responses to FGFR inhibition with and without radiation therapy were evaluated by growth delay assays in two colorectal xenograft mouse models (NMRI nu/nu mice injected with NCI-H716 or CaCo2 cells).

Bioluminescence imaging of therapy response does not correlate with FDG-PET response in a mouse model of Burkitt lymphoma.

Since the development and evaluation of novel anti-cancer therapies require molecular insight in the disease state, both FDG-PET and BLI imaging were evaluated in a Burkitt B-cell lymphoma xenograft model treated with cyclophosphamide or temsirolimus. Daudi xenograft mice were treated with either cyclophosphamide or temsirolimus and imaged with BLI and FDG-PET on d0 (before treatment), d2, d4, d7, d9 and d14 following the start of therapy. Besides tumor volume changes, therapy response was assessed with immunohistochemical analysis (apoptosis).

Molecular imaging of therapy response with (18)F-FLT and (18)F-FDG following cyclophosphamide and mTOR inhibition.

Purpose: Evaluation and comparison of 3'-[(18)F]-fluoro-3'-deoxy-L-thymidine (FLT) and 2-[(18)F]-fluoro-2-deoxyglucose (FDG)-PET to monitor early response following both cyclophosphamide and temsirolimus treatment in a mouse model of Burkitt lymphoma.

Methods: Daudi xenograft mice were treated with either cyclophosphamide or temsirolimus and imaged with FLT-PET and FDG-PET on appropriate days post therapy inititiation. Immunohistochemical (IHC) studies (H&E, TUNEL, CD20, PCNA and ki-67) and DNA flow cytometry studies were performed.

Investigation of possible endogenous hypoxia markers in colorectal cancer.

Objective: We evaluated the potential of some recently proposed hypoxia markers, being monocarboxylic acid transporter 1 (MCT1), MCT4 and prolyl hydroxylase 2 (PHD2); and a more established hypoxia marker, glucose transporter-1 (GLUT-1), by testing the association with the exogenous marker pimonidazole.

Materials And Methods: Paraffin embedded tumour sections of 20 colorectal cancer patients were stained for blood vessels together with either pimonidazole or carbonic anhydrase-IX (CA-IX) and single stained for MCT1, MCT4, GLUT-1, and PHD2. Expression of all markers was compared with expression of pimonidazole and micro-vessel density (MVD) and with disease-free survival (DFS) and overall survival (OS).

Radioiodinated phenylalkyl malonic acid derivatives as pH-sensitive SPECT tracers.

Introduction: In vivo pH imaging has been a field of interest for molecular imaging for many years. This is especially important for determining tumor acidity, an important driving force of tumor invasion and metastasis formation, but also in the process of apoptosis.

Methods: 2-(4-[(123)I]iodophenethyl)-2-methylmalonic acid (IPMM), 2-(4-[(123)I]iodophenethyl)-malonic acid (IPM), 2-(4-[(123)I]iodobenzyl)-malonic acid (IBMM) and 4-[(123)I]iodophthalic acid (IP) were radiolabeled via the Cu(+) isotopic nucleophilic exchange method.

Site-specific 68Ga-labeled Annexin A5 as a PET imaging agent for apoptosis.

Purpose: Two variants of Annexin A5 (Cys2-AnxA5 and Cys165-AnxA5) were labelled with Gallium-68 in order to evaluate their biological properties.

Procedures: Biodistribution and pharmacokinetics of the radiotracers were studied with μPET in healthy mice and in a mouse model of hepatic apoptosis. μPET imaging after IV injection of the tracers in combination with μMRI was performed in Daudi tumor bearing mice before and after treatment with a combination of chemotherapy and radiotherapy.

Preclinical imaging of therapy response using metabolic and apoptosis molecular imaging.

Purpose: Early after therapy, 2-deoxy-2-[(18)F]fluoro-D-glucose ([(18)F]FDG) imaging is not always reliable due to the influx of inflammatory cells while apoptosis imaging offers a direct and early measurement of therapy effects. This study uses an improved apoptosis probe ((99m)Tc-hAnxA5) in combination with [(18)F]FDG imaging to evaluate therapy response.

Procedures: Daudi tumor tissue was implanted in the spleen of SCID mice.

Development and evaluation of a 68Ga labeled pamoic acid derivative for in vivo visualization of necrosis using positron emission tomography.

In this study, we labeled N,N'-bis(diethylenetriamine pentaacetic acid)-pamoic acid bis-hydrazide (bis-DTPA-PA) with the generator produced PET radionuclide gallium-68 and evaluated 68Ga-bis-DTPA-PA as a potential tracer for in vivo visualization of necrosis by positron emission tomography (PET). Radiolabeling was achieved with a decay-corrected radiochemical yield of 63%. Biodistribution and in vivo stability studies in normal mice showed that 68Ga-bis-DTPA-PA is cleared faster from normal tissue than the previously reported 99mTc(CO)3 complex with bis-DTPA-PA which on the other hand is more stable in vivo.

18F-FLT and 18F-FDG PET to measure response to radiotherapy combined with celecoxib in two colorectal xenograft models.

Purpose: To determine the dependence of celecoxib on the tumour micro-environment in vitro and in vivo and to compare the use of (18)F-Fluorodeoxyglucose ((18)F-FDG) and (18)F- 3'-deoxy-3-fluorothymidine ((18)F-FLT) to measure tumour response.

Materials And Methods: In vitro, colony assays were performed on a cyclo-oxygenase 2 (COX-2) negative (HCT116) and a COX-2 positive cell line (HCA7). Xenograft models of these cell lines were treated with celecoxib and/or radiotherapy.