Maslinic Acid Inhibits Colon Tumorigenesis by the AMPK-mTOR Signaling Pathway

Maslinic acid (MA), a natural triterpenoid abundant in olives, has a variety of bioactivities. However, its effects and mechanisms on colorectal cancer (CRC) still need to be explored. This research evaluated the effects of MA on CRC progression from the aspect of the adenosine monophosphate (AMP)-activated protein kinase (AMPK)-mammalian target of rapamycin (mTOR) pathway. MA inhibited the proliferation and migration of HCT116 and SW480 cells while inducing apoptosis in these cells. Furthermore, it could activate AMPK and negatively regulate the mTOR pathway. Knockdown of AMPK abolished its inhibitory effect on cell proliferation and migration and blocked the MA-induced apoptosis, revealing that AMPK was associated with the anticancer activity of MA. In addition, MA significantly suppressed the tumorigenesis and regulated the AMPK-mTOR pathway in azoxymethane/dextran sulfate sodium mice and xenograft tumor mice. This study demonstrated that the regulation of AMPK-mTOR signaling could potentially contribute to the beneficial effects of MA, including the prevention of CRC.