In vitro uptake of a new cholesteryl carborane ester compound by human glioma cell lines

The cellular uptake and retention of a new cholesteryl carborane ester compound, cholesteryl 1,12-dicarba-closo-dodecaboranel-carboxylate (BCH), by two human glioma cell lines, glioblastoma multiforme SF-763 and SF-767, was evaluated. BCH, which is an extremely hydrophobic compound, was formulated into liposomes and incubated with two human glioma tumor cell lines and one human normal neuron cell line. The amount of BCH uptake by the cells was measured by high performance liquid chromatography. The effects of BCH concentration in the culture medium and the incubation time on the cellular uptake of BCH were studied. In addition, BCH uptake by tumor cells was examined in the presence and absence of lipoprotein in the culture medium. It was found that the amount of BCH taken by the glioma cell lines was much more (up to 14 times) than that by the normal neuron cell line. The cellular uptake of BCH was related to the amount of BCH in the medium as well as the incubation time. The cellular uptake of BCH by SF-763 and SF-767 cells after 16 h of incubation was 283.3 +/- 38.9 and 264.0 +/- 36.5 microg boron/g cells, respectively. The majority of BCH taken up in tumor cells was retained after the subsequent incubation. In the presence of lipoprotein, the cellular uptake of BCH by SF-767 tumor cells was about four times as much as that in the absence of lipoprotein. In conclusion, the cellular uptake of BCH by glioma cells was about 14 times higher than by normal neuron cells. The uptake in glioma cells was up to 10 times higher than that required for successful cancer treatment and BCH was well retained in the tumor cells. Lipoprotein seemed to have an important role in the BCH uptake by glioma cells.