Correction to: The relationship between endogenous thymidine concentrations and [F]FLT uptake in a range of preclinical tumour models.

Unfortunately, the original version of Figs. 4, 5 and 6b in the article [1] contained errors in the n numbers as indicated on the columns. Please note that column heights and error bars in the original figures and data in the ESM tables are correct and statistical tests are valid.

3'-Deoxy-3'-[F]Fluorothymidine Uptake Is Related to Thymidine Phosphorylase Expression in Various Experimental Tumor Models.

Purpose: We recently reported that high thymidine phosphorylase (TP) expression is accompanied by low tumor thymidine concentration and high 3'-deoxy-3'-[F]fluorothymidine ([F]FLT) uptake in four untreated lung cancer xenografts. Here, we investigated whether this relationship also holds true for a broader range of tumor models.

Procedures: Lysates from n = 15 different tumor models originating from n = 6 institutions were tested for TP and thymidylate synthase (TS) expression using western blots.

The relationship between endogenous thymidine concentrations and [(18)F]FLT uptake in a range of preclinical tumour models.

Background: Recent studies have shown that 3'-deoxy-3'-[(18)F] fluorothymidine ([(18)F]FLT)) uptake depends on endogenous tumour thymidine concentration. The purpose of this study was to investigate tumour thymidine concentrations and whether they correlated with [(18)F]FLT uptake across a broad spectrum of murine cancer models. A modified liquid chromatography-mass spectrometry (LC-MS/MS) method was used to determine endogenous thymidine concentrations in plasma and tissues of tumour-bearing and non-tumour bearing mice and rats.

Examining changes in [18 F]FDG and [18 F]FLT uptake in U87-MG glioma xenografts as early response biomarkers to treatment with the dual mTOR1/2 inhibitor AZD8055.

Purpose: The mTOR kinase inhibitor AZD8055 inhibits both mTORC1 and mTORC2 leading to disruption of glucose metabolism and proliferation pathways. This study assessed the impact of single and multiple doses of AZD8055 on the uptake of the glucose metabolism marker 2-deoxy-2-[(18) F]fluoro-D-glucose ([(18) F]FDG) and the proliferation marker 3'-deoxy-3'-[(18) F]fluorothymidine ([(18) F]FLT) in U87-MG glioma xenografts.

Procedures: Mice bearing U87-MG tumours received either vehicle or AZD8055 (20 mg/kg) once daily p.

An evaluation of 2-deoxy-2-[18F]fluoro-D-glucose and 3'-deoxy-3'-[18F]-fluorothymidine uptake in human tumor xenograft models.

Purpose: The aim of this study is to assess the variability of 2-deoxy-2-[(18)F]fluoro-D: -glucose ([(18)F]-FDG) and 3'-deoxy-3'-[(18)F]-fluorothymidine ([(18)F]-FLT) uptake in pre-clinical tumor models and examine the relationship between imaging data and related histological biomarkers.

Procedures: [(18)F]-FDG and [(18)F]-FLT studies were carried out in nine human tumor xenograft models in mice. A selection of the models underwent histological analysis for endpoints relevant to radiotracer uptake.

Benefits of mTOR kinase targeting in oncology: pre-clinical evidence with AZD8055.

AZD8055 is a small-molecule inhibitor of mTOR (mammalian target of rapamycin) kinase activity. The present review highlights molecular and phenotypic differences between AZD8055 and allosteric inhibitors of mTOR such as rapamycin. Biomarkers, some of which are applicable to clinical studies, as well as biological effects such as autophagy, growth inhibition and cell death are compared between AZD8055 and rapamycin.

Functional comparison of annexin V analogues labeled indirectly and directly with iodine-124.

We are interested in imaging cell death in vivo using annexin V radiolabeled with (124)I. In this study, [(124)I]4IB-annexin V and [(124)I]4IB-ovalbumin were made using [(124)I]N-hydroxysuccinimidyl-4-iodobenzoate prepared by iododestannylation of N-hydroxysuccinimidyl-4-(tributylstannyl)benzoate. [(124)I]4IB-annexin V binds to phosphatidylserine-coated microtiter plates and apoptotic Jurkat cells and accumulates in hepatic apoptotic lesions in mice treated with anti-Fas antibody, while [(124)I]4IB-ovalbumin does not.

Imaging apoptosis in vivo using 124I-annexin V and PET.

Abnormal regulation of apoptosis is an important pathogenic mechanism in many diseases including cancer. Techniques to assess apoptosis in living organisms are limited and, in the case of solid organs, restricted to histological examination of biopsy samples. We investigated the use of (124)I-annexin V, which binds to phosphatidylserine (PS) on the surface of apoptotic cells, as a potential positron emission tomography (PET) radioligand for the noninvasive measurement of apoptosis in vivo.

MBP-annexin V radiolabeled directly with iodine-124 can be used to image apoptosis in vivo using PET.

A noninvasive method of measuring programmed cell death in the tumors of cancer patients using positron-emission tomography (PET) would provide valuable information regarding their response to therapeutic intervention. Our strategy is to radiolabel annexin V, a protein that binds to phosphatidylserine moieties that are translocated to the external leaflet of plasma membranes during apoptosis. We developed a phosphatidylserine-ELISA capable of distinguishing wild type from point mutant annexin V that is known to have a lower phosphatidylserine binding affinity.