Bufotalin

Bufotalin is a steroid lactone isolated from Venenum Bufonis with potently antitumor activities. Bufotalin induces cancer cell apoptosis and also induces endoplasmic reticulum (ER) stress activation^[1][2]. In Vitro: Bufotalin (0.1-2.5 μM; 12-96 hours) treatment dose- and time-dependently inhibits MG-63 osteoblastoma cell survival^[1].
Bufotalin (0.5-2.5 μM; 48 hours) treatment dose-dependently increases the percentage of Annexin V positive cells (apoptotic cells) and caspase-12 activity in MG-63 cells. Bufotalin-induced osteoblastoma cell apoptosis is associated with caspase-12 activation^[1].
Bufotalin (0.5-2.5 μM; 12 hours) treatment dose-dependently induces C/EBP homologous protein (CHOP) expression as well as PERK and IRE1 phosphorylation in MG-63 cells. Bufotalin induces endoplasmic reticulum (ER) stress activation in cells^[1].
Bufotalin treatment induces cell cycle arrest at G2/M phase through down-regulation of Aurora A, CDC25, CDK1, cyclin A and cyclin B1, as well as up-regulation of p53 and p21 in HepG2 cells. Bufotalin treatment also induces apoptosis which was accompanied by decrease in mitochondrial membrane potential, increases in intracellular calcium level and reactive oxygen species production, activations of caspase-9 and -3, cleavage of poly ADP-ribose polymerase (PARP) as well as changes in the expressions of bcl-2 and bax^[2]. In Vivo: Bufotalin (0.5-1 mg/kg; intraperitoneal injection; twice daily; for 7 days) treatment shows a significantly reduced tumor growth in mice^[1].