Walsuronoid B induces mitochondrial and lysosomal dysfunction leading to apoptotic rather than autophagic cell death via ROS/p53 signaling pathways in liver cancer

• Published in: Biochemical pharmacology Vol. 142; pp. 71 - 86
• Main Authors: Geng, Ya-di, Zhang, Chao, Lei, Jian-li, Yu, Pei, Xia, Yuan-zheng, Zhang, Hao, Yang, Lei, Kong, Ling-yi
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 15.10.2017
• Subjects: Animals; Antineoplastic Agents, Phytogenic - isolation & purification; Antineoplastic Agents, Phytogenic - pharmacology; Antineoplastic Agents, Phytogenic - therapeutic use; Apoptosis; Apoptosis - drug effects; Autophagy - drug effects; Bridged-Ring Compounds - isolation & purification; Bridged-Ring Compounds - pharmacology; Bridged-Ring Compounds - therapeutic use; Cell cycle arrest; Cell Cycle Checkpoints - drug effects; Cell Proliferation - drug effects; Cell Survival - drug effects; Dose-Response Relationship, Drug; Hep G2 Cells; Humans; Limonins - isolation & purification; Limonins - pharmacology; Limonins - therapeutic use; Liver cancer cell; Liver Neoplasms - metabolism; Liver Neoplasms - pathology; Liver Neoplasms, Experimental - drug therapy; Liver Neoplasms, Experimental - metabolism; Liver Neoplasms, Experimental - pathology; Lysosomes - metabolism; Lysosomes - physiology; Meliaceae - chemistry; Membrane Potential, Mitochondrial - drug effects; Mice, Inbred BALB C; Mice, Nude; p53; Reactive Oxygen Species - metabolism; ROS; Signal Transduction; Tumor Suppressor Protein p53 - metabolism; Walsuronoid B; Xenograft Model Antitumor Assays; DMSO; Cell cycle arrest; Walsuronoid B (PubChem CID: 16724460); Bafilomycin A1 (PubChem CID: 6436223); Liver cancer cell; Baf A1; MTT; Walsuronoid B; p53; CSA; NAC; Cisplatin (PubChem CID: 2767); Cyclosporin A (PubChem CID: 5284373); ROS; Sodium phenylbutyrate (PubChem CID: 5258); Apoptosis
• ISSN: 0006-2952; 1873-2968
• DOI: 10.1016/j.bcp.2017.06.134

[Display omitted] Walsuronoid B is a limonoid compound extracted from Walsura robusta. Previous studies have shown that limonoid compounds possess anti-cancer potential, although the molecular mechanism of this activity remains elusive. In this study, we demonstrated for the first time that walsuronoid B inhibited cell proliferation in several human cancer lines. Liver cancer cells (HepG2 and Bel-7402) were chosen for their high sensitivity to walsuronoid B. Walsuronoid B induced cell death through G2/M phase arrest and apoptosis and induced the accumulation of autophagosomes through the suppression of mTOR signaling, which serves as a cell survival mechanism and prevents cell death. We further examined the molecular mechanisms and found that walsuronoid B-induced dysfunction of the mitochondria and lysosomes rather than the endoplasmic reticulum contributed to its cell death effect. Walsuronoid B enhanced the generation of hydrogen peroxide, nitric oxide and superoxide anion radical, resulting in elevated levels of reactive oxygen species (ROS). In addition, ROS induced by walsuronoid B upregulated p53 levels; conversely, p53 stimulated ROS. These results suggested that ROS and p53 reciprocally promoted each other’s production and cooperated to induce liver cancer cell death. We found that the induction of ROS and p53 significantly triggered G2/M phase arrest and mitochondrial and lysosomal apoptosis. Finally, walsuronoid B suppressed tumor growth in vivo with few side effects. In summary, our findings demonstrated that walsuronoid B caused G2/M phase arrest and induced mitochondrial and lysosomal apoptosis through the ROS/p53 signaling pathway in human liver cancer cells in vitro and in vivo.