Could 99mTc-glucarate be used to evaluate tumour necrosis? In vitro and in vivo studies in leukaemic tumour cell line U937.
OBJECTIVE
The aim of this study was to determine whether (99m)Tc-glucarate ((99m)Tc-GLA) is a powerful and discriminant tumour necrosis marker.


METHODS
The induction of apoptosis and secondary necrosis (by a chemotherapeutic agent) and necrosis (by intense hyperthermia) was studied on an in vitro and in vivo leukaemic cell line model (U937). The percentage of apoptosis/necrosis in vitro was determined by flow cytometry after staining cells with annexin-V-fluorescein/propidium iodide. The uptake of (99m)Tc-GLA was studied after treatments that produce an optimal of necrosis cells or apoptotic cells. Three populations of interest: viable, apoptotic and necrotic cells were sorted by flow cytometry. The uptake and the intracellular distribution of (99m)Tc-GLA on each population have been studied. We also investigated the influence of necrosis on (99m)Tc-GLA uptake in a model of U937 xenografts in nude mice.


RESULTS
The accumulation of (99m)Tc-GLA in untreated and apoptotic cells was lower than in necrotic cells. Cell sorting discriminated each cellular population and showed a 14% accumulation in necrotic cells and no more than a 3% in apoptotic cells. In apoptotic and viable cells, (99m)Tc-GLA is distributed between the cytosolic/membrane and the nucleus fractions. In necrotic cells, (99m)Tc-GLA is mainly found in the nucleus fraction. In vivo investigations showed a higher (99m)Tc-GLA uptake in necrotic tumour than in apoptotic and control ones.


CONCLUSIONS
(99m)Tc-GLA may be a useful agent to specifically evaluate tumour necrosis and may be helpful for the follow-up of patients with cancer.
Perek
Nathalie
N
Cancer Research Group IFRESIS 143, Faculty of Medicine, Saint-Etienne, France. nathalie.perek@univ-st-etienne.fr
Sabido
Odile
O
Le Jeune
Nathalie
N
Prevot
Nathalie
N
Vergnon
Jean-Michel
JM
Clotagatide
Anthony
A
Dubois
Francis
F
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000627:therapeutic use; D017209:Apoptosis; D002470:Cell Survival; D005047:Etoposide / Q000627:therapeutic use; D005937:Glucaric Acid / Q000031:analogs & derivatives*; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000473:pathology*; D051379:Mice; D008819:Mice, Nude; D009336:Necrosis; D009368:Neoplasm Transplantation; D015609:Organotechnetium Compounds; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D014183:Transplantation, Heterologous; D020298:U937 Cells
D000972:Antineoplastic Agents, Phytogenic; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C067171:technetium Tc 99m glucarate; D005047:Etoposide; D005937:Glucaric Acid