Inhibitor of apoptosis protein Livin promotes tumor progression and chemoradioresistance in human anaplastic thyroid cancer.

Anaplastic thyroid cancer (ATC) is characterized by a rapid and aggressive course of progression. Despite significant advances in surgery, radiotherapy and chemotherapy, the disease‑specific mortality due to ATC is approximately 100%. New strategies, such as molecular targeted therapies, are imperative for improving survival. Livin, a member of the human inhibitor of apoptosis protein family, has been found to be associated with tumor progression and poor prognosis in various human cancers. The aim of the present study was to evaluate the role of Livin in cancer progression and chemoradioresistance of ATC and to investigate its potential as a therapeutic target. Endogenous Livin expression in the human BHT101 ATC cell line was silenced by Livin‑specific small interfering RNA. To assess the impact of Livin on cancer cell behavior in human ATC cells, various methods such as cell invasion, cell viability and cell apoptosis assays were applied. To assess the expression of Livin and the change of apoptosis‑related proteins associated with Livin expression, reverse transcription‑quantitative PCR and western blotting were performed. Immunohistochemistry was performed to detect Livin protein expression in human ATC tissues. The association between Livin expression and apoptotic/proliferation index was analyzed in human ATC cells. Livin‑knockdown suppressed tumor cell invasion; and conversely, it enhanced cell apoptosis, with elevated expression levels of cleaved caspase‑3 and ‑7 and cleaved PARP. Livin‑knockdown enhanced radiation‑induced apoptosis, while reducing cell viability following radiotherapy, as well as lenvatinib treatment. In addition, human ATC tissues with high Livin‑expression exhibited a high Ki‑67 labeling index and low apoptotic index. In summary, these findings indicate the contribution of Livin to tumor progression and chemoradioresistance in ATC.