METALLOTHIONEIN IN A HUMAN CELL-LINE - RESPONSE OF HELA-CELLS TO CADMIUM AND ZINC

HeLa cells, derived from a human cervical carcinoma, are able to accumulate cadmium in culture. The majority of the Cd2+ is bound to a protein identified as metallothionein (MT) by its elution volume on a Sephadex G-75 column ( Ve Vo = 1.8). Increased amounts of Cd2+ are found in MT as the concentration of extracellular Cd2+ is raised from 10-8 m to 10-5 m. HeLa cells also incorporate labeled cystine into MT in response to Cd2+. The HeLa CdMT separates into two major forms on DEAE ion-exchange chromatography. HeLa cells also bind 65Zn to MT and incorporate labeled cystine into MT when exposed to 5 × 10-5 m Zn2+. Maximal MT synthesis in HeLa cells in response to Zn2+ is as great as that observed in response to Cd2+. Cycloheximide inhibits incorporation of labeled cystine into MT, as well as a large percentage of the binding of 109Cd and 65Zn to MT. Our data suggest that the potential to synthesize MT is not limited to cells derived from organs known to accumulate Cd2+ and Zn2+, such as the liver, kidney, and intestine. © 1979.