Abstract
Acute promyelocytic leukemia (APL) is characterized by a specific chromosomal translation, resulting in a fusion gene that affects the differentiation, proliferation and apoptosis of APL cells. Epigallocatechin-3-gallate (EGCG), a catechin, exhibits numerous biological functions, including antitumor activities. Previous studies have reported that EGCG induces apoptosis in NB4 cells. However, the molecular mechanism underlying EGCG-induced apoptosis remains unclear. The present study aimed to determine the molecular basis of EGCG-induced apoptosis in NB4 cells. EGCG treatment significantly inhibited the viability of NB4 cells in a dose-dependent manner. In addition, EGCG treatment induced apoptosis and increased the levels of (Bcl-2-like protein 4) Bax protein expression. Moreover, EGCG treatment was able to increase phosphorylated (p)-p38α mitogen-activated protein kinase (MAPK) and Src homology 1 domain-containing protein tyrosine phosphatase (SHP-1) expression. Pretreatment with PD169316 (a p38 MAPK inhibitor) partially blocked EGCG-induced apoptosis and inhibited EGCG-mediated Bax expression. Similarly, pretreatment with NSC87877, an inhibitor of SHP-1, partially blocked EGCG-induced apoptosis and inhibited EGCG-mediated increases in p-p38α MAPK and Bax expression. Therefore, the results of the present study indicate that EGCG is able to induce apoptosis in NB4 cells via the SHP-1-p38αMAPK-Bax cascade.