Galla Rhois water extract inhibits lung metastasis by inducing AMPK-mediated apoptosis and suppressing metastatic properties of colorectal cancer cells

Galla Rhois is a commonly used medicine in East Asia for the treatment of several diseases. However, the effects of Galla Rhois on the metastasis of colorectal cancer (CRC) and the underlying molecular mechanisms have not been studied. We investigated the anti-metastatic properties of Galla Rhois water extract (GRWE) on metastatic CRC cells. The effect of GRWE on the viability of colon 26 (CT26) cells was evaluated using WST-8 assay. Annexin V assay and western blot analysis were performed to elucidate the underlying molecular mechanisms involved in apoptosis. GRWE suppressed viability of CT26 cells by inducing apoptosis through the cleavage of caspase-3 and PARP, downregulation of caspase-8, caspase-9, Bcl-2 and Bcl-xL, and upregulation of Bax. Metastatic phenotypes such as epithelial-mesenchymal transition (EMT), migration, and invasion of CRC cells were investigated by real-time reverse transcription polymerase chain reaction, wound healing assay, and matrigel invasion assay, respectively. Non-cytotoxic concentrations of GRWE inhibited EMT in CRC cells by regulating the expression of EMT markers. GRWE attenuated cell migration and invasion through the inhibition of matrix metalloproteinase (MMP)-2 and MMP-9 activity. Moreover, GRWE suppressed colorectal lung metastasis in vivo, suggestive of its potential application for the treatment of colorectal metastasis.