Tackling the Cytotoxic Effect of a Marine Polycyclic Quinone-Type Metabolite: Halenaquinone Induces Molt 4 Cells Apoptosis via Oxidative Stress Combined with the Inhibition of HDAC and Topoisomerase Activities

• Published in: Marine drugs Vol. 13; no. 5; pp. 3132 - 3153
• Main Authors: Shih, Shou-Ping, Lee, Man-Gang, El-Shazly, Mohamed, Juan, Yung-Shun, Wen, Zhi-Hong, Du, Ying-Chi, Su, Jui-Hsin, Sung, Ping-Jyun, Chen, Yu-Cheng, Yang, Juan-Cheng, Wu, Yang-Chang, Lu, Mei-Chin
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 20.05.2015; MDPI
• Subjects: Animals; Antigens, Neoplasm; Apoptosis - drug effects; bcl-2-Associated X Protein - metabolism; Benzoquinones - metabolism; Cell Line, Tumor; Cytochromes c - metabolism; DNA Topoisomerases, Type II; DNA-Binding Proteins - antagonists & inhibitors; Female; halenaquinone; histone deacetylase (HDAC); Histone Deacetylase Inhibitors - pharmacology; Histone Deacetylases - metabolism; Humans; K562 Cells; Membrane Potential, Mitochondrial - drug effects; Mice; Mice, Nude; mitochondria; Mitochondria - drug effects; Mitochondria - metabolism; NF-kappa B - metabolism; Oxidative Stress - drug effects; Poly(ADP-ribose) Polymerases - metabolism; Protein Kinase Inhibitors - pharmacology; Proto-Oncogene Proteins c-bcl-2 - metabolism; Quinones - pharmacology; reactive oxygen species (ROS); Reactive Oxygen Species - metabolism; topoisomerase; topoisomerase; histone deacetylase (HDAC); halenaquinone; reactive oxygen species (ROS); mitochondria
• ISSN: 1660-3397; 1660-3397
• DOI: 10.3390/md13053132

A marine polycyclic quinone-type metabolite, halenaquinone (HQ), was found to inhibit the proliferation of Molt 4, K562, MDA-MB-231 and DLD-1 cancer cell lines, with IC50 of 0.48, 0.18, 8.0 and 6.76 μg/mL, respectively. It exhibited the most potent activity against leukemia Molt 4 cells. Accumulating evidence showed that HQ may act as a potent protein kinase inhibitor in cancer therapy. To fully understand the mechanism of HQ, we further explored the precise molecular targets in leukemia Molt 4 cells. We found that the use of HQ increased apoptosis by 26.23%-70.27% and caused disruption of mitochondrial membrane potential (MMP) by 17.15%-53.25% in a dose-dependent manner, as demonstrated by Annexin-V/PI and JC-1 staining assays, respectively. Moreover, our findings indicated that the pretreatment of Molt 4 cells with N-acetyl-l-cysteine (NAC), a reactive oxygen species (ROS) scavenger, diminished MMP disruption and apoptosis induced by HQ, suggesting that ROS overproduction plays a crucial rule in the cytotoxic activity of HQ. The results of a cell-free system assay indicated that HQ could act as an HDAC and topoisomerase catalytic inhibitor through the inhibition of pan-HDAC and topoisomerase IIα expression, respectively. On the protein level, the expression of the anti-apoptotic proteins p-Akt, NFκB, HDAC and Bcl-2, as well as hexokinase II was inhibited by the use of HQ. On the other hand, the expression of the pro-apoptotic protein Bax, PARP cleavage, caspase activation and cytochrome c release were increased after HQ treatment. Taken together, our results suggested that the antileukemic effect of HQ is ROS-mediated mitochondrial apoptosis combined with the inhibitory effect on HDAC and topoisomerase activities.