IL13R[alpha]2 siRNA inhibited cell proliferation, induced cell apoptosis, and suppressed cell invasion in papillary thyroid carcinoma cells

Aim: Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Infiltrative growth and metastasis are the two most intractable characteristics of PTC. Interleukin-13 receptor [alpha]2 (IL13R[alpha]2) with high affinity for Th2-derived cytokine IL-13 has been reported to be overexpressed in several tumors. In this study, an analysis of IL13R[alpha]2 expression in PTC and matched paracancerous tissues was undertaken, and its biologic functions in PTC were assessed. Methods: IL13R[alpha]2 and vascular endothelial growth factor (VEGF) expression were detected by using real-time polymerase chain reaction and immunohistochemistry analyses. Cell proliferation, invasion, apoptosis, and caspase activity were measured with the Cell Counting Kit-8, Transwell, flow cytometry analyses, and biochemistry assay, respectively. Results: Upregulation of IL13R[alpha]2 and VEGF was observed in PTC tissues compared with matched paracancerous tissues. Pearson's correlation analysis indicated that IL13R[alpha]2 mRNA level in the tested PTC tissues was positively correlated with VEGF mRNA level. Besides, inhibited cell proliferation, induced cell apoptosis, and suppressed cell invasion were detected in IL13R[alpha]2-silenced TPC-1 cells. Increased activity of Caspase 3 and Caspase 9, along with elevated cleaved Caspase 3 and poly (ADP)-ribose polymerase indicated the signal pathway of cell apoptosis induced by IL13R[alpha]2 siRNA. In addition, downregulated metastasis- and angiogenesis-related proteins VEGF, VEGFR2, MMP2, and MMP9 indicated the decreased number of invading cells after knockdown of IL13R[alpha]2. Conclusion: The results demonstrate that IL13R[alpha]2 plays an important role in the progress of PTC. IL13R[alpha]2 knockdown in PTC cells inhibited cell proliferation, induced cell apoptosis, and suppressed cell invasion. These data suggest that IL13R[alpha]2 may be a novel therapeutic target in the treatment of PTC clinically. Keywords: papillary thyroid carcinoma, IL13R[alpha]2 siRNA, metastasis