Yuanhuacine (YC), a
daphnane diterpenoid from the flowers of Daphne genkwa, exhibited a potential growth inhibitory activity against human
non-small cell lung cancer (NSCLC) cells. YC also suppressed the invasion and migration of
lung cancer cells. However, the precise molecular mechanisms remain to be elucidated. In the present study, we report that YC significantly activated
AMP-activated protein kinase (AMPK) signaling pathway and suppressed mTORC2-mediated downstream signaling pathway in H1993 human NSCLC cells. AMPK plays an important role in energy metabolism and
cancer biology. Therefore, activators of AMPK signaling pathways can be applicable to the treatment of
cancer. YC enhanced the expression of p-AMPKα. The co-treatment of YC and compound C (an AMPK inhibitor) or
metformin (an AMPK activator) also confirmed that YC increases p-AMPKα. YC also suppressed the activation of the
mammalian target of rapamycin (mTOR) expression, a downstream target of AMPK. Further study revealed that YC modulates mTORC2-associated downstream signaling pathways with a decreased expressions of p-Akt, p-
protein kinase C alpha (PKCα), p-
ras-related C3 botulinum toxin substrate 1 (Rac1) and filamentous actin (
F-actin) that are known to activate cell growth and organize actin cytoskeleton. In addition, YC inhibited the
tumor growth in H1993 cell-implanted xenograft nude mouse model. These data suggest the YC could be a potential candidate for
cancer chemotherapeutic agents derived from natural products by regulating AMPK/
mTORC2 signaling pathway and actin cytoskeleton organization.