Role of FeCl₃ in ⁶⁷Ga uptake by HeLa S3 cells in vitro

Abstract

The effect of FeCl₃ on ⁶⁷Ga uptake by HeLa S3 cells was studied in vitro. Uptake of ⁶⁷Ga by HeLa S3 cells was influenced by the concentration of serum in the medium and especially that of transferrin added to the medium. Therefore, it is assumed that a mechanism of ⁶⁷Ga uptake exists mediated by transferrin. However, when 10^-2–10^-1 mM FeCl₃ was added to the medium in the same experimental system, a remarkable increase of ⁶⁷Ga uptake was noted. Results of equilibrium dialysis, showed that binding of ⁶⁷Ga to transferrin was inhibited by the administration of FeCl₃. Moreover, the formation of a complex of ⁶⁷Ga and FeCl₃, which did not pass through the cellulose membrane, was observed. A correlation was found between an increase in ⁶⁷Ga uptake by HeLa S3 cells and the formation of the ⁶⁷Ga−Fe complex. These results indicate that another mechanism of ⁶⁷Ga accumulation, namely the formation of a ⁶⁷Ga−Fe complex plays a role in the uptake of ⁶⁷Ga by tumor cells in the presence of iron.