Establishment and characterization of cell lines from three human thyroid carcinomas: responses to all-trans-retinoic acid and mutations in the BRAF gene

Abstract

We report the characteristics of three cell lines (designated, SNU-80, SNU-373 and SNU-790), which were established from two papillary carcinomas and one anaplastic carcinoma obtained from three Korean thyroid carcinoma patients. All cell lines grow as adherent cells. Electron microscopy characteristically showed cytoplasmic invaginations of nuclei and intranuclear cytoplasmic inclusions. SNU-80 and SNU-790 cells showed a positive reaction to anti-cytokeratin antibody, and SNU-790 cells positivity for CK-19. All lines were free of mycoplasma or bacteria and were proven unique by DNA fingerprinting analysis. The p15 and p16 genes are deleted in the SNU-790 line. Mutations of the p53 gene were found in two lines (SNU-80 and SNU-373), but no mutations in the RET or MEN1 genes were observed. Mutations of the BRAF gene were found in the SNU-80 (G468R) and the SNU-790 (V599E) cell lines, but no mutations in the K-ras gene were present. SNU-80 and SNU-790 cells showed a positive reaction to anti-cytokeratin antibody, and no evidence of the production of thyroglobulin or calcitonin was observed. The cell lines were unable to trap radioactive iodine but did not contain TSH receptor. In addition, we investigated the mRNA expression levels of Tg, TSHR, TTF-1, PAX-8, NIS, IL-6, and LIF, and of the alpha, beta and gamma retinoic acid receptors in these cell lines. IL-6 was down-regulated in all three cell lines by all-trans-retinoic acid treatment. RAR-alpha was expressed but RAR-beta was not expressed in the three cell lines, and RAR-gamma was not expressed in SNU-790. Interestingly, RAR-beta (SNU-80 and SNU-373) and RAR-gamma (SNU-790) was up-regulated by all-trans-retinoic acid treatment. We believe that these well-characterized thyroid carcinoma cell lines may be useful tools for investigations on the biological characteristics of thyroid carcinoma, particularly for investigations related to gene alterations, especially of the BRAF gene. These cell lines may also be useful for redifferentiation therapy studies on thyroid carcinoma using all-trans-retinoic acid.