Abstract:

Objective To investigate the relationship between dedifferentiation of differentiated thyroid carcinoma (DTC) cell line FTC-133 cultured in vitro and radioactive iodine (¹³¹I) radiation. Methods DTC FTC-133 cells cultured in vitro were divided into experiment group (long-term cultivation after Na¹³¹I radiation for 48 h), control group (long-term cultivation without Na¹³¹I radiation) and blank group (cryopreservation and revitalization for experiment). Iodide uptake of each group was determined, and RT-PCR, Western blotting and radioimmunoassay (RIA) were employed to detect the expression of thyroglobulin (Tg), thyroid peroxidase (TPO), sodium-iodide symporter (NIS) and thyroid-stimulating hormone receptor (TSHR) mRNA and protein. Results The iodide uptake rate of blank group was the highest and that of experiment group was the lowest, with significant differences among groups (P<0.01). Compared with blank group, the expression of Tg, TPO, NIS and TSHR protein in experiment group and control group decreased, especially in experiment group, with significant differences among groups (P<0.05). The changes of expression of Tg, TPO, NIS and TSHR mRNA were in accordance with those of expression of Tg, TPO, NIS and TSHR protein. Conclusion DTC FTC133 cells may experience dedifferentiation during long-term in vitro culture, and ¹³¹I radiation may promote this process, which may be associated with decreased expression of thyroid specific protein.

Key words: differentiated thyroid carcinoma, dedifferentiation, radioactive iodine, radiation