Accumulation of m-iodobenzylguanidine by neuroblastoma cells results from independent uptake and storage mechanisms.

The modalities of uptake and storage of iodine-labeled m-iodobenzylguanidine (MIBG) by four human neuroblastoma cell lines have been studied. SK-N-BE(2)C cell line has been shown to possess the specific (type 1) MIBG uptake, as well as an efficient extravesicular storage mechanism. Conversely, LAN-5 cells, which show a nonsaturation kinetic of MIBG incorporation, lack only the ability to efficiently store the MIBG taken up by a mechanism that can be pharmacologically defined as uptake 1. The two other neuroblastoma cell lines tested, GI-LI-N and GI-CA-N, lack both uptake and storage capacity. In view of the fact that the only detailed study on specific MIBG uptake by a human neuroblastoma cell line has been carried out on SK-N-SH, a highly heterogeneous cell line, our report provides new insights on the molecular and cellular pharmacology of radiolabeled MIBG.