20(S)-ginsenoside Rh2 induces caspase-dependent promyelocytic leukemia-retinoic acid receptor A degradation in NB4 cells via Akt/Bax/caspase9 and TNF-α/caspase8 signaling cascades

Sirui Zhu; Xiaoli Liu; Mei Xue; Yu Li; Danhong Cai; Shijun Wang; Liang Zhang

doi:10.1016/j.jgr.2020.05.001

20(S)-ginsenoside Rh2 induces caspase-dependent promyelocytic leukemia-retinoic acid receptor A degradation in NB4 cells via Akt/Bax/caspase9 and TNF-α/caspase8 signaling cascades

J Ginseng Res. 2021 Mar;45(2):295-304. doi: 10.1016/j.jgr.2020.05.001. Epub 2020 May 15.

Authors

Sirui Zhu¹, Xiaoli Liu¹, Mei Xue², Yu Li¹, Danhong Cai¹, Shijun Wang³, Liang Zhang¹

Affiliations

¹ Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210023, PR China.
² College of Basic Medical Sciences, Institute of TCM-related Comorbid Depression, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210023, PR China.
³ Shandong co-innovation center of TCM formula, College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, Shandong, 250035, PR China.

Abstract

Background: Acute promyelocytic leukemia (APL) is a hematopoietic malignancy driven by promyelocytic leukemia-retinoic acid receptor A (PML-RARA) fusion gene. The therapeutic drugs currently used to treat APL have adverse effects. 20(S)-ginsenoside Rh2 (GRh2) is an anticancer medicine with high effectiveness and low toxicity. However, the underlying anticancer mechanisms of GRh2-induced PML-RARA degradation and apoptosis in human APL cell line (NB4 cells) remain unclear.

Methods: Apoptosis-related indicators and PML-RARA expression were determined to investigate the effect of GRh2 on NB4 cells. Z-VAD-FMK, LY294002, and C 87, as inhibitors of caspase, and the phosphatidylinositol 3-kinase (PI3K) and tumor necrosis factor-α (TNF-α ) pathways were used to clarify the relationship between GRh2-induced apoptosis and PML-RARA degradation.

Results: GRh2 dose- and time-dependently decreased NB4 cell viability. GRh2-induced apoptosis, cell cycle arrest, and caspase3, caspase8, and caspase9 activation in NB4 cells after a 12-hour treatment. GRh2-induced apoptosis in NB4 cells was accompanied by massive production of reactive oxygen species, mitochondrial damage and upregulated Bax/Bcl-2 expression. GRh2 also induced PML/PML-RARA degradation, PML nuclear bodies formation, and activation of the downstream p53 pathway in NB4 cells. Z-VAD-FMK inhibited caspase activation and significantly reversed GRh2-induced apoptosis and PML-RARA degradation. GRh2 also upregulated TNF-α expression and inhibited Akt phosphorylation. LY294002, an inhibitor of the PI3K pathway, enhanced the antitumor effects of GRh2, and C 87, an inhibitor of the TNF-α pathway, reversed NB4 cell viability, and GRh2-mediated apoptosis in a caspase-8-dependent manner.

Conclusion: GRh2 induced caspase-dependent PML-RARA degradation and apoptosis in NB4 cells via the Akt/Bax/caspase9 and TNF-α/caspase8 pathways.

Keywords: 20(S)-ginsenoside Rh2; Acute promyelocytic leukemia; Apoptosis; Caspase; PML-RARA.