[Effects of estrogen and thyroid hormone on EGF receptor expression, proliferative activity and SCC production in the...

This study was undertaken to see if estrogen and thyroid hormone affected EGF-receptor (EGF-R) expression, proliferative activity and intracellular SCC levels in uterine cervical squamous carcinoma cells. The uterine cervical cancer cell line (CaSki) was cultured in vitro in the absence or presence of 17 beta-estradiol (E2) or L-triiodothyronine (T3) in a serum free condition. Effects of E2 or T3 on the characteristics of EGF-R were assessed by the Scatchard analysis of the binding assay with 125I-EGF. Cellular levels of EGF-R expression were examined by the immunoperoxidase method with a monoclonal antibody to EGF-R. Proliferative activity of the cells was determined by proliferating cell nuclear antigen (PCNA) immunostaining, 3H-thymidine uptake and the number of cells. The effects of E2 or T3 on intracellular SCC levels were also examined by determining the intracellular SCC concentration with an SCC-RIA Kit. The scatchard analysis of 125I-EGF binding to CaSki cells showed that the addition of E2 or T3 had little effect on the affinity of EGF-R for CaSki cells but increased the capacity of EGF-R for the cells. Immunocytochemical staining with anti EGF-R antibody demonstrated that EGF-R expression in the CaSki cells was augmented by the addition of E2 or T3. The addition of E2 or T3 also resulted in an increase in 3H-thymidine uptake by the CaSki cells, the PCNA positive rate and the number of cells. Furthermore the addition of E2 or T3 increased intracellular SCC in the CaSki cells.(ABSTRACT TRUNCATED AT 250 WORDS)