miRNA expression in a human papillary thyroid carcinoma cell line varies with invasiveness

The purpose of these studies was to explore the expression pattern of miRNAs associated with invasion and metastasis of human papillary thyroid carcinoma (PTC). A transwell invasion chamber was used to select progressively more invasive cancer cell populations from a clonal cell line of human PTC with cervical lymph node metastasis, IHH-4. Three sublines with progressive invasiveness, designated IHH-4M-1, IHH-4M-2 and IHH-4M-3, were obtained through this in vitro selection process. The sublines manifested an increase in colony-forming ability on soft agar and metastatic potency in nude mice. Then metastasis-related miRNAs differentially expressed between them were analyzed utilizing the miRNA microarray technique. We found that 11 metastasis-related miRNAs were differentially expressed between the invasive subpopulations and their control subpopulations; these miRNAs may account for their significant difference in the invasion capabilities and favor lymphatic metastasis of PTC.