Abstract: Objective To explore the effects of potassium iodate (KIO3) on the proliferation, cell cycle, and the mRNA/protein levels of cyclin D1 and Ki67 of SW579 cells, a human thyroid squamous carcinoma cell line. Methods The effects of different doses of KIO3（0，10-6，10-5，10-4，10-3，10-2，10-1 mol/L）on SW579 cell proliferation were assessed by CCK8 method. SW579 cells were then treated with 0 (control), 10-6 or 10-2 mol/L KIO3 for 48 h. The cell cycle was measured by flow cytometry. The mRNA and protein levels of cyclinD1 and Ki67 were respectively analyzed by real-time PCR and western blot. Results We found that 10-6 and 10-2 mol/L of KIO3 respectively exhibited the most promoting and suppressive effect on SW579 cell proliferation. Both 10-6 mol/L and 10-2 mol/L KIO3 decreased the cell population at G1 phase (P < 0.05) but increased the cell population at S phase (P < 0.05); 10-6 mol/L KIO3 produced more prominent effects than 10-2 mol/L KIO3. KIO3 at the dose of 10-6 mol/L significantly up-regulated the mRNA levels of cyclin D1 and ki67 in cells(P < 0.05) ; whereas, the mRNA and protein levels of cyclin D1 and ki67were significantly down-regulated in cells treated with 10-2 mol/L KIO3 (P < 0.05) . Conclusion Different doses of KIO3 affect the proliferation and cell cycle of SW579 cells probably via regulating the levels of cyclin D1 and ki67.

Key words: Key words: Thyroid cancer, Potassium iodate, Cyclin D1, Ki67