p63 inhibits CD44+/CD24− cell proliferation and chemoresistance in papillary thyroid carcinoma cells

Thyroid cancer typically has a good prognosis; however, the risks of recurrence and chemoresistance associated with thyroid cancer remain a cause for concern. Papillary thyroid carcinoma (PTC) comprises 80% of all cases of thyroid carcinoma. A previous study reported that cluster of differentiation (CD) 44+/CD24- PTC cells may contribute to PTC recurrence and chemoresistance; however, the underlying molecular mechanisms remain elusive. In the present study, CD44+/CD24- cells were isolated from the TPC-1 PTC cell line and biological function assays revealed that CD44+/CD24- cells were significantly more proliferative and chemoresistant compared with CD44-/CD24- cells. Furthermore, the expression level of p63 was demonstrated to be negatively correlated with the expression of CD44 in PTC cells. The role of p63 in CD44+/CD24- cell proliferation and chemoresistance was investigated and, the ectopic expression of p63 was observed to significantly inhibit CD44+/CD24- cell proliferation and chemoresistance in vitro and in vivo. In conclusion, the present study indicated that CD44+/CD24- cells contribute to PTC proliferation and chemoresistance and that the suppression of p63 in CD44+/CD24- cells contributes to these effects.