Influence of Dehydroxymethylepoxyquinomicin on Radiosensitivity of Thyroid Carcinoma TPC-1 Cells

Objective. To investigate the influence of dehydroxymethylepoxyquinomicin (DHMEQ), an NF-kappa B inhibitor, on radiosensitivity of thyroid carcinoma (TC) TPC-1 cells. Methods. The isolation of CDl33 positive cells (CD133(+) TPC-1) and negative cells (CD133(-) TPC-1) from TPC-1 cells used immunomagnetic bead sorting. After verification of the toxicity of DHMEQ to cells by MTT and cell cloning assays, the cells were divided into four groups, of which three groups were intervened by DHMEQ, I-131 radiation, and DHMEQ +I-131 radiation, respectively, while the fourth group was used as a control without treatment. Alterations in cell growth, apoptosis, and cell cycle were observed. Results. DHMEQ had certain toxic effects on TPC-1 cells, with an IC50 of 38.57 mu g/mL (P < 0.05). DHMEQ inhibited CD133(+) and CD133- TPC-1 proliferation and their clonogenesis after irradiation. DHMEQ + radiation contributed to a growth inhibition rate and an apoptosis rate higher than either or them alone (P < 0.05), with a more significant effect on CD133(-) TPC-1 than CD133+ TPC-1 under the same treatment conditions (P < 0.05). Conclusion. DHEMQ can increase the radiosensitivity of TC cells to I-131, inhibit tumor cell growth, and promote apoptosis. However, its effect is less significant on CD133(+) TPC-1 compared with CD133(-) TPC-1, which may be related to the stem cell-like properties of CD133(+) cells. In the future, the application of DHMEQ in TC 131I radiotherapy will effectively improve the clinical effect of patients.