PT  - JOURNAL ARTICLE
AU  - Jirka Grosse
AU  - Daniela Grimm
AU  - Christoph Eilles
AU  - Johann Schoenberger
TI  - Influence of thyreotropin on mechanisms of apoptosis and radiation resistance of thyroid carcinoma cells
DP  - 2009 May 01
TA  - Journal of Nuclear Medicine
PG  - 1589--1589
VI  - 50
IP  - supplement 2
4099  - http://jnm.snmjournals.org/content/50/supplement_2/1589.short
4100  - http://jnm.snmjournals.org/content/50/supplement_2/1589.full
SO  - J Nucl Med2009 May 01; 50
AB  - 1589 Objectives Higher concentrations of thyreotropin (TSH) have to be considered as an exogenic stress factor. Using two poorly differentiated thyroid carcinoma cell lines we examined the influence of such a high concentration on molecules that act in a pro- and antiapoptotic manner. Methods The ML-1 and FTC-133 cell line were investigated. Bcl-2, fas, p53, bax and caspase-3 were determined (flow cytometry and western blot) after stimulation for 72 h, 2 and 4 weeks with 60 mU/l TSH. Apoptosis was induced by in vitro irradiation with 30 Gy X-rays. Apoptosis was evaluated native, 2 d and 4 d after irradiation by flow cytometry with FITC-labeled annexin V. Results Expression of bcl-2 was influenced extensively under the influence of TSH. Based on the basic value (ML-1 15%, FTC-133 10%) a reduction to 2% and 3% was detectable with an increase after 4d. In both cell lines caspase-3 showed a clear decrease that accelerated in the course of the study. Under stimulation with TSH p53 showed an obvious increase in FTC-133 cells. Stimulation with TSH caused a change of the native rate of apoptosis in ML-1 cells and an increasing radiation resistance in both cell lines (p<0.05). Conclusions High concentrations of TSH lead to considerable changes in the expression of molecules that act in a pro- and antiapoptotic manner. The increased radiation resistance under stimulation with thyreotropin is a sign of the clinical relevance. Because this effect is detectable in two different cell lines one could expect that other thyroid carcinoma cell lines will show similar reactions.