Ethacridine induces apoptosis and differentiation in thyroid cancer cells in vitro

Abstract

Background/Aim: Ethacridine is used as a topical antiseptic as well as for second-trimester abortion. Recent studies showed that ethacridine is an inhibitor of poly(ADP-ribose) glycohydrolase (PARG) and an activator of the transcriptional coactivator with PDZ-binding motif (TAZ). This study examined the effects of ethacridine on thyroid cancer cells. Materials and Methods: Thyroid cancer cell lines (FTC133 and SW1736) and thyroid follicular epithelial cells (Nthy-ori 3-1) were treated with ethacridine. Viability, clonogenicity, cell-cycle distribution, and apoptosis were evaluated. The expression of thyroid differentiation markers (TTF-1, PAX8, and NIS) was determined by real-time PCR. Results: Ethacridine suppressed cell growth and clonogenic ability of thyroid cancer cells in a time- and dose-dependent manner (p<0.001). No cell-cycle arrest was found, but ethacridine dose-dependently induced apoptosis of thyroid cancer cells (p<0.001). The PAX8 and NIS expressions were significantly increased in SW1736 (3.41-fold and 1.53-fold, respectively) and Nthy-ori 3-1 cells (2.73-fold and 4.12-fold, respectively). Conclusion: Ethacridine elicits apoptotic cell death in thyroid cancer cells and promotes differentiation in a subset of thyroid follicular cells.