B4G2 Induces Mitochondrial Apoptosis by the ROS-Mediated Opening of Ca2+-Dependent Permeability Transition Pores

Abstract

Background/Aims: Hepatocellular carcinoma (HCC) is the most common type of liver cancer. At present, only sorafenib is approved to treat HCC. In this study, we found that a 23-hydroxybetulinic acid derivative, B4G2, exhibited potent antiproliferative activity in HCC cell lines. Methods: We used four HCC cell lines (HepG2, HepG2/ADM, Hep3B and Bel-7402) to evaluate the anti-tumour activity and explore underlying mechanisms by which B4G2 induces apoptosis. Results: Among these cell lines, HepG2 showed the highest sensitivity to B4G2. HepG2 cells treated with B4G2 showed a depolarized mitochondrial membrane potential, released cytochrome c, activated caspase-9 and caspase-3 and cleaved poly ADP-ribose polymerase (PARP). However, Z-VAD-FMK, a pan-caspase inhibitor, did not attenuate B4G2-induced apoptosis, implying that the induction of mitochondrial apoptosis by B4G2 may be independent of caspases. Moreover, pre-treatment with MgCl₂, a blocker of Ca²⁺-dependent permeability transition (PT) pores, attenuated the depolarization of the mitochondrial potential and decreased the population of apoptotic cells, indicating that B4G2-induced apoptosis was partly dependent on the opening of the Ca²⁺-dependent PT pores. B4G2 also increased the levels of intracellular calcium and reactive oxygen species (ROS). Furthermore, an ROS scavenger, N-acetyl-cysteine (NAC), markedly decreased the accumulation of intracellular calcium and apoptosis. Conclusion: This is the first demonstration that B4G2 inhibits the growth of HCC cells and induces mitochondrial apoptosis in hepatocellular carcinoma cells by the ROS-mediated opening of Ca²⁺-dependent permeability transition pores.

Protodioscin Induces Apoptosis Through ROS-Mediated Endoplasmic Reticulum Stress via the JNK/p38 Activation Pathways in Human Cervical Cancer Cells

“…ROS generation is known to be an important factor in tumor cell death [26, 27]. To further confirm the role of ROS on PD-mediated apoptosis, HeLa and C33A cells were treated with PD to elevate levels of intracellular ROS production (Fig.…”

3,3′-Diindolylmethane Suppresses the Growth of Hepatocellular Carcinoma by Regulating Its Invasion, Migration, and ER Stress-Mediated Mitochondrial Apoptosis

“…Calcium can act as a key regulator in mitochondria to stimulate ATP synthesis. Previously, numerous studies have suggested that efflux of Ca 2+ from ER to mitochondria can result in mitochondrial dysfunction, causing overproduction of ROS, which in turn results in cell death [ 75 , 76 ]. Several studies have reported that overproduction of mitochondrial ROS can result in mitochondrial membrane depolarization, causing a loss in mitochondrial membrane potential which initiates mitochondrial-dependent apoptotic pathway [ 4 , 77 ].…”

A sensitive HPLC–MS/MS method for the simultaneous determination of anemoside B4, anemoside A3 and 23‐hydroxybetulinic acid: Application to the pharmacokinetics and liver distribution of Pulsatilla chinensis saponins

“…The beneficial roles of P. chinensis saponins in liver cancer management at both the cellular and animal levels have received increasing attention (Luo et al, ; Xu et al, ). Anemoside B4 and 23‐hydroxybetulinic acid both exhibited cytotoxicity against the human liver cancer cell line HepG2 by inducing apoptosis, with similar half maximal inhibitory concentration (IC 50 ) values of 31.6 and 32.44 μ m , respectively (Wang, Zheng, & Gao, ; Yao et al, ). Given their strong activity and high exposure in the target organ, the liver, and in systemic plasma, 23‐hydroxybetulinic acid and anemoside B4 are probably responsible for the anti‐hepatoma effect of P. chinensis saponins.…”