Huaier inhibits autophagy and promotes apoptosis in T-cell acute lymphoblastic leukemia by down-regulating SIRT1

Abstract

Objective: Due to the high drug resistance and relapse rate of T-cell acute lymphoblastic leukemia (T-ALL), the prognosis is usually poor. Therefore, there is an urgent need to find safer and more effective therapeutic drugs. Huaier and its preparations, as adjuvant drugs, have been widely used in the treatment of solid tumors and other diseases. However, the application of Huaier in leukemia is rarely reported. In this study, we investigated the anti-tumor effect of Huaier on T- ALL and its underlying mechanism. Methods: Jurkat and MOLT-4 cells were treated with Huaier. Cell viability was evaluated by CCK-8 assay. The morphological changes of apoptotic cells were observed by Hoechst 33258 staining. Cell apoptosis was analyzed by flow cytometry. The expression levels of related proteins were assessed by Western blot. Results: The results showed that Huaier significantly inhibited the proliferation of Jurkat and MOLT-4 cells in a dose- and time-dependent manner, with IC50 of 2.37 ± 0.10 and 1.93 ± 0.07 mg/mL at 48 h, respectively. Morphological changes and increased number of apoptotic cells were observed by Hoechst 33258 staining and flow cytometry. The apoptosis rates of Jurkat and MOLT-4 cells in 4 mg/mL group were 50.67 ± 1.36 % and 49.97 ± 5.43 %, respectively. Huaier promoted the expression of Cytochrome c, Cleaved Caspase-3, Cleaved PARP, p53, LC3-Ⅱ and p62 proteins, while inhibited the expression of SIRT1, ATG7 and Beclin 1 proteins. Treatment with SRT1720 (SIRT1 agonist) combined with Huaier rescued Huaier-induced apoptosis and increased the expression of autophagy-related proteins. Conclusion: Huaier inhibits autophagy and promotes apoptosis of T-ALL cells by down-regulating SIRT1, which may be a potential drug for the treatment of T-ALL.

Keywords

• Huaier
• T-cell acute lymphoblastic leukemia
• SIRT1
• Apoptosis
• Autophagy