Stemness potency and structural characteristics of thyroid cancer cell lines

Background: Thyroid cancer is the most frequent type of endocrine malignancy. Thyroid carcinomas are derived from the follicular epithelium and classified as papillary (PTC) (85%), follicular (FTC) (12%), and anaplastic (ATC) (<3%). Thyroid cancer could arise from thyroid cancer stem-like cells (CSCs). CSCs are cancer cells that feature stem-like properties. Kruppel-like factor (KLF4) and Stage-spesific embryonic antigen 1 (SSEA-1) are types of stem cell markers. Filamentous actin (F-actin) is an essential part of the cellular cytoskeleton. The purpose of this study was to evaluate the stem cell potency and the spatial distribution of the cytoskeletal element F-actin in PTC, FTC, and ATC cell lines.

Materials and methods: Normal thyroid cell line (NTC) Nthy-ori-3-1, PTC cell line BCPAP, FTC cell line FTC-133 and ATC cell line 8505c were stained with SSEA-1 and KLF4 for stem cell potency and F-actin for cytoskeleton. The morphological properties of cells were assessed by a scanning electron microscope (SEM) and elemental ratios were compared with EDS.

Results: PTCs had greater percentages of SSEA-1 and KLF4 protein intensity (0.32% and 0.49%, respectively) than NTCs. ATCs had a greater proportion of KLF4 expression (0.8%) than NTCs. NTCs and FTCs had increased F-actin intensity across the cell, but PTCs had the lowest among these four cell lines. NTCs and PTCs, as well as NTCs and FTCs, have statistically identical aspect ratios and round values. These values, however, were statistically different in ATCs.

Conclusion: The study of stem cell markers and the cytoskeletal element F-actin in cancer and normal thyroid cell lines may assist in the identification of new therapeutic targets and contribute in the understanding of treatment resistance mechanisms.