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Downregulation of TIGAR sensitizes the antitumor effect of physapubenolide through increasing intracellular ROS levels to trigger apoptosis and autophagosome formation in human breast carcinoma cells.
Biochem Pharmacol. 2017 11 01; 143:90-106.BP

Abstract

Physapubenolide (PB) is a cytotoxic withanolide isolated from Physalis angulata that was used as a traditional Chinese medicine. In this study, we investigated the role of TIGAR and ROS in PB-induced apoptosis and autophagosome formation in human breast carcinoma MDA-MB-231 and MCF-7 cells. PB induced apoptosis by decreasing mitochondrial membrane potential and elevating the Bax/Bcl-2 protein expression ratio in MDA-MB-231 and MCF-7 cells. Caspase inhibitor Z-VAD-FMK treatment partly blocked PB induced cytotoxicity, suggesting that apoptosis serves as an important role in the anti-proliferative effect of PB. Meanwhile, PB induced autophagosome formation, as characterized by increased acridine orange-stained positive cells, accumulation of punctate LC3B fluorescence and a greater number of autophagic vacuoles under electron microscopy. Furthermore, PB inhibited autophagic flux as reflected by the overlapping of mCherry and GFP fluorescence when MDA-MB-231 cells were transfected with GFP-mCherry-LC3 plasmid. Depletion of LC3B, ATG5 or ATG7 reduced PB-induced cytotoxicity, indicating that autophagosome associated cell death participated in the anti-cancer effect of PB. Moreover, PB-induced apoptosis and autophagosome formation were linked to the generation of intracellular ROS, and pre-treatment with the antioxidant NAC obviously mitigated the effects. Interestingly, PB treatment slightly increased TIGAR expression at low concentrations but decreased TIGAR expression drastically at high concentrations. Downregulation of TIGAR by small interfering RNA augmented low concentrations of PB-induced apoptosis and autophagosome formation, which contributed to the observed anti-cancer effect of PB and were reversed by NAC pre-treatment. Consistently, in MDA-MB-231 or MCF-7 xenograft mouse model, PB suppressed tumor growth through ROS induced apoptosis and autophagosome associated cell death accompanied with the downregulation of TIGAR. Taken together, these results indicate that downregulation of TIGAR increased PB-induced apoptosis and autophagosomes associated cell death through promoting ROS generation in MDA-MB-231 and MCF-7 cells.

Authors+Show Affiliations

State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing 210009, China.State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing 210009, China.State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing 210009, China.State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing 210009, China. Electronic address: luojg@cpu.edu.cn.State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing 210009, China. Electronic address: cpu_lykong@126.com.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

28774732

Citation

Ma, Ting, et al. "Downregulation of TIGAR Sensitizes the Antitumor Effect of Physapubenolide Through Increasing Intracellular ROS Levels to Trigger Apoptosis and Autophagosome Formation in Human Breast Carcinoma Cells." Biochemical Pharmacology, vol. 143, 2017, pp. 90-106.
Ma T, Zhang Y, Zhang C, et al. Downregulation of TIGAR sensitizes the antitumor effect of physapubenolide through increasing intracellular ROS levels to trigger apoptosis and autophagosome formation in human breast carcinoma cells. Biochem Pharmacol. 2017;143:90-106.
Ma, T., Zhang, Y., Zhang, C., Luo, J. G., & Kong, L. Y. (2017). Downregulation of TIGAR sensitizes the antitumor effect of physapubenolide through increasing intracellular ROS levels to trigger apoptosis and autophagosome formation in human breast carcinoma cells. Biochemical Pharmacology, 143, 90-106. https://doi.org/10.1016/j.bcp.2017.07.018
Ma T, et al. Downregulation of TIGAR Sensitizes the Antitumor Effect of Physapubenolide Through Increasing Intracellular ROS Levels to Trigger Apoptosis and Autophagosome Formation in Human Breast Carcinoma Cells. Biochem Pharmacol. 2017 11 1;143:90-106. PubMed PMID: 28774732.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Downregulation of TIGAR sensitizes the antitumor effect of physapubenolide through increasing intracellular ROS levels to trigger apoptosis and autophagosome formation in human breast carcinoma cells. AU - Ma,Ting, AU - Zhang,Yi, AU - Zhang,Chao, AU - Luo,Jian-Guang, AU - Kong,Ling-Yi, Y1 - 2017/08/01/ PY - 2017/05/14/received PY - 2017/07/24/accepted PY - 2017/8/5/pubmed PY - 2017/10/11/medline PY - 2017/8/5/entrez KW - Apoptosis KW - Autophagy KW - Physapubenolide KW - Physapubenolide (PubChem CID: 101317813) KW - ROS KW - TIGAR SP - 90 EP - 106 JF - Biochemical pharmacology JO - Biochem. Pharmacol. VL - 143 N2 - Physapubenolide (PB) is a cytotoxic withanolide isolated from Physalis angulata that was used as a traditional Chinese medicine. In this study, we investigated the role of TIGAR and ROS in PB-induced apoptosis and autophagosome formation in human breast carcinoma MDA-MB-231 and MCF-7 cells. PB induced apoptosis by decreasing mitochondrial membrane potential and elevating the Bax/Bcl-2 protein expression ratio in MDA-MB-231 and MCF-7 cells. Caspase inhibitor Z-VAD-FMK treatment partly blocked PB induced cytotoxicity, suggesting that apoptosis serves as an important role in the anti-proliferative effect of PB. Meanwhile, PB induced autophagosome formation, as characterized by increased acridine orange-stained positive cells, accumulation of punctate LC3B fluorescence and a greater number of autophagic vacuoles under electron microscopy. Furthermore, PB inhibited autophagic flux as reflected by the overlapping of mCherry and GFP fluorescence when MDA-MB-231 cells were transfected with GFP-mCherry-LC3 plasmid. Depletion of LC3B, ATG5 or ATG7 reduced PB-induced cytotoxicity, indicating that autophagosome associated cell death participated in the anti-cancer effect of PB. Moreover, PB-induced apoptosis and autophagosome formation were linked to the generation of intracellular ROS, and pre-treatment with the antioxidant NAC obviously mitigated the effects. Interestingly, PB treatment slightly increased TIGAR expression at low concentrations but decreased TIGAR expression drastically at high concentrations. Downregulation of TIGAR by small interfering RNA augmented low concentrations of PB-induced apoptosis and autophagosome formation, which contributed to the observed anti-cancer effect of PB and were reversed by NAC pre-treatment. Consistently, in MDA-MB-231 or MCF-7 xenograft mouse model, PB suppressed tumor growth through ROS induced apoptosis and autophagosome associated cell death accompanied with the downregulation of TIGAR. Taken together, these results indicate that downregulation of TIGAR increased PB-induced apoptosis and autophagosomes associated cell death through promoting ROS generation in MDA-MB-231 and MCF-7 cells. SN - 1873-2968 UR - https://www.unboundmedicine.com/medline/citation/28774732/Downregulation_of_TIGAR_sensitizes_the_antitumor_effect_of_physapubenolide_through_increasing_intracellular_ROS_levels_to_trigger_apoptosis_and_autophagosome_formation_in_human_breast_carcinoma_cells_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0006-2952(17)30506-3 DB - PRIME DP - Unbound Medicine ER -