Differential effects of natural flavonoids on growth and iodide content in a human Na*/I- symporter-transfected follicular thyroid carcinoma cell line.
OBJECTIVE
Natural flavonoids (plant pigments) have been shown to inhibit thyroid peroxidase (TPO) in vitro and the growth of thyroid cancer cell lines. We have studied the role of flavonoids on the iodide transport and the growth of the human follicular thyroid cancer cell line (FTC133) which was stably transfected with the human Na(+)/I(-) symporter (hNIS).


METHODS
Cells were treated with flavonoids (0.5-50 microM) for 0, 2, 4 and 6 days; (125)I content and (125)I efflux of the cells and DNA content were measured.


RESULTS
Cell growth was inhibited significantly at day 6 by most flavonoids. Eight out of ten flavonoids decreased the (125)I content of the cells at day 4. Morin did not influence the (125)I content of the cells and, surprisingly, myricetin increased the (125)I content of the cells. Kaempferol, apigenin, luteolin and F21388 decreased NIS mRNA expression after 15, 29 and 48 h; after 96 h NIS mRNA returned to normal.


CONCLUSIONS
As TPO is not present in this cell line, the effects of the flavonoids on the iodide uptake are not related to organification. Myricetin was the only flavonoid studied that increased the influx and decreased the efflux of iodide. The effect of myricetin (decreased growth and increased retention of iodide) can be of therapeutic value in the radioiodide treatment of thyroid carcinoma.
Schröder-van der Elst
Janny P
JP
Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands. J.P.van_der_Elst@LUMC.nl
van der Heide
Daan
D
Romijn
Johannes A
JA
Smit
Jan W A
JW
D018263:Adenocarcinoma, Follicular; D001692:Biological Transport / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor / Q000187:drug effects / Q000502:physiology; D005419:Flavonoids / Q000494:pharmacology*; D006801:Humans; D007454:Iodides / Q000378:metabolism*; D007457:Iodine Radioisotopes; D012333:RNA, Messenger / Q000032:analysis; D027981:Symporters / Q000235:genetics* / Q000378:metabolism; D013964:Thyroid Neoplasms; D014162:Transfection; D000099209:Sodium-Iodide Symporters
D005419:Flavonoids; D007454:Iodides; D007457:Iodine Radioisotopes; D012333:RNA, Messenger; D027981:Symporters; D000099209:Sodium-Iodide Symporters