Buddlejasaponin IV induces apoptotic cell death by activating the mitochondrial‑dependent apoptotic pathway and reducing α2β1 integrin‑mediated adhesion in HT‑29 human colorectal cancer cells.

Colon cancer is one of the most frequent malignant neoplasms worldwide. Epidemiological studies suggested that the development of colon cancer can be prevented by plant‑derived ingredients. In the present study, the chemopreventive activity of buddlejasaponin IV (BS‑IV), isolated from the aerial part of Pleurospermum kamtschaticum, was investigated using cell viability, DNA fragmentation, caspase‑3 activity, anoikis, cell adhesion, and flow cytometry assays and a murine lung metastasis model. Protein expression levels were detected by western blotting. Treatment with BS‑IV significantly reduced cell viability and caused DNA fragmentation in HT‑29 human colorectal cancer cells. BS‑IV increased the ratio of Bax to Bcl‑2 by significantly inhibiting Bcl‑2 expression levels. BS‑IV reduced expression levels of procaspase‑9, procaspase‑3, and full‑length poly (ADP‑ribose) polymerase (PARP) and increased cleaved PARP and nonsteroidal anti‑inflammatory drug activated gene‑1 expression levels and caspase‑3 activity. In addition, BS‑IV decreased the attachment of HT‑29 cells to the extracellular matrix proteins collagen type I and IV and downregulated cell surface expression of α2β1 integrin by inhibiting its glycosylation. BS‑IV also reduced the expression and phosphorylation levels of focal adhesion kinase (FAK) and Akt, and the reduced FAK and Akt levels were rescued by treatment with a caspase‑3 inhibitor Z‑VAD‑FMK. Furthermore, orally administered BS‑IV inhibited the formation of tumor nodules in Balb/C mice intravenously injected with CT‑26 murine colorectal cancer cells. Collectively, these findings indicated that BS‑IV induces apoptosis via the mitochondrial‑dependent pathway by increasing the ratio of Bax to Bcl‑2 and activating caspases. BS‑IV also induces anoikis by inhibiting α2β1 integrin‑mediated cell adhesion and signaling and inhibits the lung metastasis of colon cancer cells. Therefore, BS‑IV may serve as a promising cancer chemopreventive agent.