Growth inhibition of human papillary thyroid carcinoma cells and multicellular spheroids by anti-EGF-receptor antibody
Gabler, B.; Aicher, T.; Heiss, P.; Senekowitsch-Schmidtke, R.
Anticancer Research 17(4b): 3157-3159
1997
ISSN/ISBN: 0250-7005 PMID: 9329625 Document Number: 478696
EGF has been reported to stimulate thyroid cell proliferation. In the present study we investigated the effects of anti-EGF-R-antibody (Mab 4253 both as monolayers and spheroids of an oxyphilic, non iodine metabolizing, papillary thyroid carcinoma cell line (ONCO-DG-1) and roughly characterized their EGF-R. Scatchard analysis with I-125-labeled-EGF demonstrated a low number of 1.5 times 10-4 EGF-R per monolayer cell (KD 4.1 times 10-10 M) and only 6 times 10-3 EGF-R per spheroids cell (KD 5.0 times 10-10 M). Already 80% of the binding sites were blocked by only 0.44 mu-g/ml Mab 425. Proliferating activity and EGF-R were found to be regularly distributed throughout the spheroids. Adding Mab 425 to medium containing 1 ng/ml EGF, inhibited the growth of monolayer cells by 15% (1 ng/ml Mab 425) and 28% (10 ng/ml Mab 425), measured by the MTT-test. The volume growth of spheroids was inhibited by 10-15% using 2 mu-g/ml Mab 425, whereas their viability (MTT-Test) was almost identical. The results show that the anti-EGF-R-antibody (Mab 425) alone is not effective enough for therapeutical use, but it could be of clinical value in conjugation with radionuclides (e.g. I-131) in order to reach metastases not metabolizing iodine.