Binucleated HeLa cells are formed by cytokinesis failure in starvation and keep the potential of proliferation

Many cytological studies have reported that the numbers of binucleated cells were elevated in various tumors. However, binucleated cells are observed in not only malignant tumors but also normal tissues. Thus, the clinical significance of binucleated cells is controversial. Here we attempted to elucidate the characteristics of binucleated HeLa cells using time-lapse microscopy. To examine the frequency, viability, proliferation, and formation mechanism of binucleated cells, we grew HeLa cells on chamber slides and tissue culture dishes in DMEM supplemented with (10, 3, 1 and 0.5 % media) and without fetal bovine serum (0 % medium). The proliferation was evaluated by the medium improvement examination (cultured for 2 more days in 10% medium after culturing in 0% medium; starvation). In the 0 % medium, 150 binucleated cells were formed by cytokinesis failure. There were significantly more binucleated cells in the 0 % medium than in the 10, 3, 1 and 0.5 % media. About twice the number of binucleated cells underwent mitosis in the improvement examinations than in the serum-free examination. We found here that starvation induced the binucleation of HeLa cells and that some binucleated cells can reproduce. These findings might be helpful for understanding binucleated cells in tumors.