Biological implications of PTEN upregulation and altered sodium/iodide symporter intracellular distribution in resveratrol-suppressed anaplastic thyroid cancer cells

Objective: Anaplastic thyroid cancer/ATC is a highly aggressive malignancy with extremely poor prognosis. Resveratrol/Res promotes re-differentiation of cancer cells and exerts inhibitory effects on ATC cells. Sodium/iodide symporter/NIS and phosphate and tension homology deleted on chromsome ten/PTEN levels are positively correlated with the grade of thyroid cancer differentiation, while the impact of Res on them remain unknown. Materials and Methods: The patterns of NIS and PTEN expression and intracellular distribution in THJ-16T and THJ-21T ATC and Nthy-ori 3-1 normal thyroid cells and their relevance with Res-caused ATC suppression were investigated via multiple experimental methods. E-cadherin was cited as a re-differentiation biomarker of ATC cells. Results: MTT and EdU cell proliferation assays showed distinct growth suppression in ATC cells after Res treatment. TUNEL staining revealed extensive apoptosis of Res-treated THJ-16T and THJ-21T rather than Nthy-ori 3-1 cells. Western blotting, immunocytochemical/ICC and double-labeled immunofluorescent/IF staining showed increased PTEN levels accompanied with distinct NIS and PTEN nuclear co-translocation in Res-treated THJ-16T and THJ-21T cells. E-cadherin but not NIS appeared on the outer membrane. Conclusion: PTEN upregulation and the concurrent NIS and PTEN nuclear translocation in Res-suppressed ATC cells may indicate the better therapeutic outcome and would be a group of beneficial prognostic factors of ATCs.