Hispolon is an active
phenolic compound of <i>Phellinus igniarius</i>, a mushroom
that was recently shown to have antioxidant and anticancer
activities in various solid tumors. Here, the molecular mechanisms
by which hispolon exerts anticancer effects in acute myeloid leukemia
(AML) cells was investigated. The results showed that hispolon suppressed
cell proliferation in the various AML cell lines. Furthermore, hispolon
effectively induced apoptosis of HL-60 AML cells through caspases-8,
-9, and -3 activations and PARP cleavage. Moreover, treatment of HL-60
cells with hispolon induced sustained activation of JNK1/2, and inhibition
of JNK by JNK1/2 inhibitor or JNK1/2-specific siRNA significantly
abolished the hispolon-induced activation of the caspase-8/-9/-3.
In vivo, hispolon significantly reduced tumor growth in mice with
HL-60 tumor xenografts. In hispolon-treated tumors, activation of
caspase-3 and a decrease in Ki67-positive cells were observed. Our
results indicated that hispolon may have the potential to serve as
a therapeutic tool to treat AML