Resibufogenin inhibits the malignant characteristics of multiple myeloma cells by blocking the PI3K/Akt signaling pathway

Abstract

Resibufogenin (RBG) is an active ingredient of toad venom that also has antitumor potential. The present study aimed to investigate the role of RBG in multiple myeloma (MM) and the underlying action mechanism involving the PI3K/Akt signaling pathway. A human MM cell line, RPMI8226, was treated with RBG and/or insulin-like growth factor 1 (IGF-1; an activator of the PI3K/AKT signaling pathway). Cell viability and apoptosis were detected using Cell Counting Kit-8 and flow cytometry, respectively. Cell migration and invasion were detected using a Transwell assay. In addition, the epithelial-mesenchymal transition (EMT)-associated proteins (E-cadherin, N-cadherin and Vimentin) and the PI3K/AKT pathway-associated proteins [AKT, phosphorylated (p)-AKT, PI3K and p-PI3K] were measured using western blotting. RBG inhibited the viability, migration and invasion, and promoted the apoptosis of RPMI8226 cells in a dose-dependent manner. RBG at concentrations of 4 and 8 µM upregulated E-cadherin, and downregulated N-cadherin and Vimentin in RPMI8226 cells. RBG also decreased the protein expression of p-AKT and p-PI3K in a dose-dependent manner. In addition, the intervention of IGF-1 weakened the inhibitory effects of RBG on the malignant characteristics of MM cells. RBG-induced inhibition of EMT and the PI3K/AKT pathway were also weakened by IGF-1 treatment. In conclusion, RBG inhibited viability, migration, invasion and EMT, and promoted the apoptosis of MM cells by blocking the PI3K/AKT signaling pathway.

E2F2 modulates cell adhesion through the transcriptional regulation of PECAM1 in multiple myeloma

“…Increasing numbers of studies have reported that EMT‐like transcriptional patterns are activated in MM 16,31–33 . To confirm whether E2F2 regulated EMT in MM, we measured the expression of EMT‐related genes in E2F2‐knockdown and E2F2‐overexpressing MM cell lines (H929 and MM.1S cells respectively).…”

“…Increasing numbers of studies have reported that EMTlike transcriptional patterns are activated in MM. 16,[31][32][33] To confirm whether E2F2 regulated EMT in MM, we measured the expression of EMT-related genes in E2F2knockdown and E2F2-overexpressing MM cell lines (H929 and MM.1S cells respectively). Our results showed that the suppression of E2F2 increased the expression of epithelial markers (TJP1 and E-cadherin [E-Cad]) and decreased the expression of mesenchymal markers (Vimentin and Twist1) (Figure 2A,B).…”