The role of insulin-like growth factor-1 (IGF-1) in follicular thyroid cancer cell line CGTH W-1

Detection of mRNA of sodium iodide symporter in benign and malignant human thyroid tissues

Human sodium iodide symporter (hNIS) is an intrinsic membrane protein with 12 transmembrane regions, which shows homology to other sodium-dependent transporters. There is controversy as to the amount of hNIS expression in different kinds of human thyroid cancer tissues and cell lines. In this study, reverse transcription-polymerase chain reaction (RT-PCR) was used to detect mRNA of hNIS in various fresh normal, benign tissues and malignant human thyroid tissues. The forward primer was nested hNIS-5' primer containing the sequences: ACCTGGAAATGCGCTTCAGC. The reverse primer was nested hNIS-3' primer containing the sequences: AAGCATGACACCGCGTGCCA. The results revealed three of three normal tissues, six of eight nodular hyperplasia, two of two hyperthyroidism, one of three follicular adenomas, five of ten papillary thyroid carcinomas, one of one follicular carcinoma and zero of one metastatic follicular tissues demonstrated positive results for hNIS in thyroid epithelial cells. A higher percentage of positive results of the symporter mRNA were found in normal benign thyroid tissues and the thyroid tissues of hyperthyroidism, and nodular hyperplasia (84.6%); however follicular adenoma, papillary and follicular thyroid carcinomas demonstrated a lower percentage of expression in the RT-PCR studies (46.7%). Serum thyrotropin levels and the degree of differentiated components presented in cancer tissues have been mentioned as important factors for hNIS expression in the cancer tissues. The discrepancies of the expression of hNIS in in vivo and in vitro studies need further investigation. In conclusion, hNIS was found in higher ratios in normal and benign thyroid tissues than in the malignant tissues. In addition, the RT-PCR technique hNIS did not detect the transporter in most papillary thyroid cancer tissues.

Establishment of xenografts and cell lines from well-differentiated human thyroid carcinoma

BACKGROUND

Our aim was to establish Chinese human thyroid cancer cell lines and to provide the material for thyroid cancer research.

METHODS

We collected thyroid cancer tissues from 93 patients with thyroid cancer for developing the primary culture. Thyroid cancer tissues were verified by frozen sections during the operations, then subjected to primary cell culture. During the first several passages, fibroblasts were removed by selective attachment.

RESULTS

From the 93 cancer tissues used, two follicular cancer tissues from the metastatic area (CGTH W-1, CGTH W-2) and one papillary thyroid cancer tissue (CGTH W-3) could be passed over 50 times. Cellular transformation with loss of contact inhibition occurred during passages 5-8. Electron microscopic studies of the CGTH W-1 cell line showed the presence of an abundance of mitochondria and Golgi complex. Presence of microvilli with interdigitations between neighboring cells were found in CGTH W-2 and CGTH W-3 cell lines. Severe combined immunodeficient (SCID) mice were used to determine whether these cells were tumorigenic. Two months after transplantation of 1 x 10(7) CGTH W-1, 2, and 3 cells into SCID mice, subcutaneous tumors approximately 2-2.5 cm in size were clearly visible. After affinity cross-linking an IGF-I with insulin-like growth factor binding proteins complex corresponding to a molecular size of 41 kDa was observed in culture media collected from CGTH W-1, SW 579, and RO82 W-1 cells.

CONCLUSIONS

Three thyroid cancer cell lines were established, which may provide material for future thyroid cancer research.