Anti-proliferative mechanism of Huaier extract in human thyroid carcinoma cells
Authors: He Jingni , Zhang Ying , Wang Lidong , Yu Yifang , Yao Baiyu , Tian Zhong 
Published: September 2020

Abstract
BackgroundThyroid cancer is the most common endocrine tumor and typically has a good prognosis; however, some patients still present with local or distant metastases. Huaier is a traditional Chinese medicine reported as effective in treating certain types of tumor, but the effect of Huaier on thyroid cancer has not yet been reported. MethodsThe thyroid cancer cell lines, B-CPAP and C643, were treated with increasing concentrations of Huaier extract and the therapeutic effect was measured using a cell counting kit 8 (CCK-8) and flow cytometry. High-throughput sequencing was further performed to identify differentially expressed genes (DEGs) in Huaier-treated B-CPAP cells. Moreover, quantitative real-time PCR (RT-qPCR) was carried out to verify the selected RNAs. Finally, the dual luciferase detection kit was used to detect gene activity.ResultsProliferation of B-CPAP and C643 cells was significantly suppressed by treatment with Huaier extract in a concentration- and time-dependent manner. Huaier extract also induced cell cycle arrest and apoptosis according to flow cytometry (p < 0.05).High-throughput sequencing observed 7,979 significantly altered transcripts. Gene Ontology (GO) analysis showed that 270 genes were enriched in upregulated terms, while 171 genes were enriched in downregulated terms (p < 0.05). Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis indicated that there were 47 enriched pathways associated with DEGs (p < 0.05). The expression levels of chosen lncRNAs (SNHG7, MIR181A2HG, ILF3-AS1, and CTA-29F11.1) and their corresponding mRNAs (BBC3, CTSL, GADD45A, and DDIT3) were verified to be overexpressed in Huaier-treated B-CPAP cells by RT-qPCR (p < 0.05).Following transduction, the CCK-8 results showed that the proliferative capacity was increased in the shRNA group as compared with that in the Ctrl and Scr groups. According to flow cytometry, the number of cells in the G0/G1 phase was decreased in the shRNA group (p < 0.01) and the apoptosis rate was lower (p < 0.05). The shRNA-treated group had significantly reduced Huaier-induced apoptosis as compared with the Scr-treated group (p < 0.05). Moreover, the number of cells in the G0/G1 phase in the shRNA-treated group was significantly lower than that in the Scr-treated group (p < 0.05). The results of the dual luciferase reporter gene experiment showed that the activity in the GADD45A WT + miR-301a-3p(+) group was significantly reduced as compared with that in the GADD45A WT + miR-301a-3p(+) NC group (p < 0.01). Further, the activity in the ILF3-AS1 WT + miR-301a-3p(+) group was significantly lower than that in the ILF3-AS1 WT + miR-301a-3p(+) NC group (p < 0.05).ConclusionsThe present study demonstrates that Huaier extract inhibits the proliferation of thyroid cancer cells via changes in the expression levels of a multitude of genes. In particular, a decrease in GADD45A expression enhances the proliferative ability of thyroid cancer cells, the levels of which can be increased by Huaier treatment, thus regulating the cell cycle and apoptosis. Huaier can inhibit the proliferation of thyroid cancer cells through the ILF3-AS1/hsa-miR-301a-3p/GADD45A ceRNA axis.