ABSTRACT
Cholecystokinin-2 (CCK-2) receptors, overexpressed in cancer types such as small cell lung cancers (SCLC) and medullary thyroid carcinomas (MTC), may serve as targets for peptide receptor radionuclide imaging. A variety of CCK and gastrin analogues has been developed, but a major drawback is metabolic instability or high kidney uptake. The minigastrin analogue PP-F11 has previously been shown to be a promising peptide for imaging of CCK-2 receptor positive tumors and was therefore further evaluated. The peptide was conjugated with one of the macrocyclic chelators DOTA, NOTA, or NODAGA. The peptide conjugates were then radiolabeled with either (68)Ga, (64)Cu, or (111)In. All (radio)labeled compounds were evaluated in vitro (IC50) and in vivo (biodistribution and PET/CT and SPECT/CT imaging). IC50 values were in the low nanomolar range for all compounds (0.79-1.51 nM). In the biodistribution studies, (68)Ga- and (111)In-labeled peptides showed higher tumor-to-background ratios than the (64)Cu-labeled compounds. All tested radiolabeled compounds clearly visualized the CCK2 receptor positive tumor in PET or SPECT imaging. The chelator did not seem to affect in vivo behavior of the peptide for (111)In- and (68)Ga-labeled peptides. In contrast, the biodistribution of the (64)Cu-labeled peptides showed high uptake in the liver and in other organs, most likely caused by high blood levels, probably due to dissociation of (64)Cu from the chelator and subsequent transchelation to proteins. Based on the present study, (68)Ga-DOTA-PP-F11 might be a promising radiopharmaceutical for PET/CT imaging of CCK2 receptor expressing tumors such as MTC and SCLC. Clinical studies are warranted to investigate the potential of this tracer.
Subject(s)
Acetates/pharmacology , Copper Radioisotopes/chemistry , Gallium Radioisotopes/chemistry , Gastrins/chemistry , Heterocyclic Compounds, 1-Ring/pharmacology , Heterocyclic Compounds/pharmacology , Indium Radioisotopes/chemistry , Animals , Cell Line, Tumor , Chelating Agents/chemistry , Female , Humans , Inhibitory Concentration 50 , Mice , Mice, SCID , Multimodal Imaging , Neoplasm Transplantation , Peptides/chemistry , Positron-Emission Tomography , Radiopharmaceuticals/chemistry , Receptor, Cholecystokinin B/metabolism , Tomography, Emission-Computed, Single-Photon , Tomography, X-Ray ComputedABSTRACT
AIMS: Development of TaqMan MGB real-time PCR assays for quantitative typing of major cattle and human-pathogenic Cryptosporidium species. METHODS AND RESULTS: Three specific TaqMan MGB real-time PCRs, based on the SSU rRNA gene, were directed towards livestock-restricted Cryptosporidium andersoni and Cryptosporidium bovis as well as both human-pathogenic Cryptosporidium parvum and Cryptosporidium hominis. A generic TaqMan assay further identified all known Cryptosporidium species and simultaneously monitored PCR inhibition through an external amplification control. The generic and specific assays were highly reproducible, and all displayed a detection limit of one oocyst per reaction. The specific TaqMan protocols also proved valuable for specifically detecting and quantifying target DNA in the presence of non-target DNA in environmental samples. CONCLUSIONS: All TaqMan MGB real-time PCR assays fulfilled the required specificity and sensitivity criteria, both on laboratory strains and on a surface water matrix. SIGNIFICANCE AND IMPACT OF THE STUDY: No molecular-based method was yet available for the quantitative detection of C. andersoni and the cluster formed by C. bovis, Cryptosporidium ryanae and Cryptosporidium xiaoi. This work provides a novel tool to evaluate the parasite load from domestic ruminants and humans, and to improve assessment and management of microbial risk through better appraisal of the origin and fate of faecal pollutions.
Subject(s)
Cryptosporidium/classification , Real-Time Polymerase Chain Reaction/methods , Animals , Base Sequence , Cattle , Cryptosporidium/genetics , Cryptosporidium/isolation & purification , DNA, Protozoan/genetics , Feces/parasitology , Genotype , Humans , Limit of Detection , Molecular Sequence Data , Oocysts/parasitology , Parasite Load , Sensitivity and Specificity , Water/parasitologyABSTRACT
Expression of the sodium iodide symporter (hNIS) has been detected in breast cancer tissue, but frequently, not at the levels necessary to mediate (131)I accumulation. Transducing the hNIS gene into breast cancer cells with adenovirus could be a tractable strategy to render breast cancer susceptible to radioiodide therapy. We constructed the replication-incompetent virus, AdSERE, in which an estrogen-responsive promoter directs the expression of hNIS. In vitro, we demonstrate that AdSERE mediates hNIS expression and iodide uptake in ER+ breast cancer cells. In vivo, we show that AdSERE-infected ER+ tumors can be imaged due to tracer accumulation; in addition, AdSERE in combination with therapeutic doses of (131)I suppresses tumor growth.
Subject(s)
Breast Neoplasms/therapy , Genetic Therapy/methods , Iodine Radioisotopes/metabolism , Radiotherapy/methods , Receptors, Estrogen/metabolism , Symporters/genetics , Symporters/metabolism , Adenoviridae , Animals , Cell Line, Tumor , Female , Fluorescent Antibody Technique , Genetic Vectors , Humans , Mice , Mice, Inbred BALB C , Tomography, X-Ray Computed , Transfection , beta-Galactosidase/metabolismABSTRACT
Oncolytic adenoviruses have shown some promise in cancer gene therapy. However, their efficacy in clinical trials is often limited, and additional therapeutic interventions have been proposed to increase their efficacies. In this context, molecular imaging of viral spread in tumours could provide unique information to rationalize the timing of these combinations. Here, we use the human sodium iodide symporter (hNIS) as a reporter gene in wild-type and replication-selective adenoviruses. By design, hNIS cDNA is positioned in the E3 region in a wild-type adenovirus type 5 (AdIP1) and in an adenovirus in which a promoter from the human telomerase gene (RNA component) drives E1 expression (AdAM6). Viruses show functional hNIS expression and replication in vitro and kinetics of spread of the different viruses in tumour xenografts are visualized in vivo using a small animal nano-SPECT/CT camera. The time required to reach maximal spread is 48 h for AdIP1 and 72 h for AdAM6 suggesting that genetic engineering of adenoviruses can affect their kinetics of spread in tumours. Considering that this methodology is potentially clinically applicable, we conclude that hNIS-mediated imaging of viral spread in tumours may be an important tool for combined anticancer therapies involving replicating adenoviruses
Subject(s)
Colonic Neoplasms/diagnostic imaging , Colonic Neoplasms/therapy , Genes, Reporter , Genetic Therapy/methods , Oncolytic Virotherapy/methods , Symporters/genetics , Tomography, Emission-Computed, Single-Photon , Adenoviridae/genetics , Adenoviridae Infections/diagnostic imaging , Animals , Colonic Neoplasms/virology , Gene Expression , Humans , Injections, Intralesional , Mice , Mice, Inbred BALB C , Neoplasm Transplantation , Transduction, Genetic/methods , Transplantation, Heterologous , Virus ReplicationABSTRACT
This report describes the diagnostic problem caused by an atypical immunoglobulin-bound creatine kinase isoenzyme in a patient who had a myocardial infarction. In the presence of this atypical isoenzyme, creatine kinase isoenzyme electrophoresis was of no help in determining whether myocardial infarction had occurred. A diagnosis of myocardial infarction was confirmed by carrying out lactate dehydrogenase isoenzyme electrophoresis and finding the characteristic increase in LD1/LD2 ratio and by following the total creatine kinase, aspartate aminotransferase and lactate dehydrogenase activities over a 5-day period. Further investigations were carried out which characterized the atypical isoenzyme as an uncommon type: creatine kinase-BB bound to immunoglobulin A lambda.
