Re-differentiation of thyroid carcinoma cell lines treated with 5-Aza-2'-deoxycytidine and retinoic acid.
We studied cell growth rate, mechanisms of growth inhibition, phenotype re-differentiation, expression of RARalpha, beta, gamma and differentiation thyroid genes before and after combined treatment with 5-Aza-CdR and RA (5-Aza/RA) of human thyroid carcinoma cell lines (FRO, WRO, TT). Furthermore, the activity and localization of the re-expressed sodium-iodide-symporter (NIS) protein was analyzed. After 5-Aza/RA treatment, all cell lines showed a significant reduction in cell growth. This was associated with apoptosis in the TT, with inhibition of cell proliferation in the WRO, and with cell cycle impairment in FRO and WRO. FRO and WRO treated with 5-Aza/RA lost the ability to grow in soft agar. FRO re-expressed thyroid transcription factor-1 and thyroglobulin, TT and WRO re-expressed PAX-8 and FRO and TT re-expressed RARbeta and NIS mRNA. Despite this expression, they were unable to take up iodine: a cytoplasmic localization of NIS protein was demonstrated in FRO. In conclusion, besides a significant reduction in cell growth rate and in the ability to grow in soft agar, treatment with 5-Aza/RA partially re-differentiated FRO and induced expression of NIS mRNA and protein in FRO and TT, but this treatment was unable to restore the functional activity of NIS, likely because it was located into the cytoplasm without reaching the plasma membrane.
Vivaldi
A
A
Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy.
Miasaki
F Y
FY
Ciampi
R
R
Agate
L
L
Collecchi
P
P
Capodanno
A
A
Pinchera
A
A
Elisei
R
R
D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D003114:Colony-Forming Units Assay; D000077209:Decitabine; D005455:Fluorescent Antibody Technique; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D009928:Organ Specificity / Q000187:drug effects; D018168:Receptors, Retinoic Acid / Q000235:genetics / Q000378:metabolism; D000072482:Retinoic Acid Receptor alpha; D027981:Symporters / Q000378:metabolism; D013964:Thyroid Neoplasms / Q000473:pathology*; D014212:Tretinoin / Q000494:pharmacology*; D000097768:Retinoic Acid Receptor gamma; D000099209:Sodium-Iodide Symporters
D001374:Azacitidine; D000077209:Decitabine; D018168:Receptors, Retinoic Acid; D000072482:Retinoic Acid Receptor alpha; D027981:Symporters; D014212:Tretinoin; D000097768:Retinoic Acid Receptor gamma; D000099209:Sodium-Iodide Symporters; C000607071:RARA protein, human; C082925:retinoic acid receptor beta