Bioaccumulation of rare earth elements in cultured HeLa cells

HeLa S-3 cells were grown in minimal essential medium supplemented with 10% calf serum and 1 mM L-glutamine without adding any rare earth elements (REEs). Exponentially growing cells were collected, and dried materials were used to analyze their REE content by inductively coupled plasma-mass spectrometry. The results showed that the cells accumulated REEs in individually different manners; namely the accumulation ratio was higher in the lighter REEs than in the heavier REEs. To deduce the implication of the accumulation of REEs in HeLa cells, the accumulation ratios for REEs were compared with those of other biologically important elements. It was seen that the accumulation ratios obtained for REEs (from 31.8 [Ce] to 14.7 [Lu]) were intermediate among those of many bioelements: Fe (124), Mg (54.5), K (38.8), Cr (12.7), Na (11.8), Mn (11.3), Zn (10.7), Ca (8.8), and V (6.7).