Cracking the Cytotoxicity Code: Apoptotic Induction of 10-Acetylirciformonin B is Mediated through ROS Generation and Mitochondrial Dysfunction

Abstract

A marine furanoterpenoid derivative, 10-acetylirciformonin B (10AB), was found to inhibit the proliferation of leukemia, hepatoma, and colon cancer cell lines, with selective and significant potency against leukemia cells. It induced DNA damage and apoptosis in leukemia HL 60 cells. To fully understand the mechanism behind the 10AB apoptotic induction against HL 60 cells, we extended our previous findings and further explored the precise molecular targets of 10AB. We found that the use of 10AB increased apoptosis by 8.9%–87.6% and caused disruption of mitochondrial membrane potential (MMP) by 15.2%–95.2% 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 HL 60 cells with N-acetyl-l-cysteine (NAC), a reactive oxygen species (ROS) scavenger, diminished MMP disruption and apoptosis induced by 10AB, suggesting that ROS overproduction plays a crucial rule in the cytotoxic activity of 10AB. The results of a cell-free system assay indicated that 10AB could act as a topoisomerase catalytic inhibitor through the inhibition of topoisomerase IIα. On the protein level, the expression of the anti-apoptotic proteins Bcl-xL and Bcl-2, caspase inhibitors XIAP and survivin, as well as hexokinase II were inhibited by the use of 10AB. On the other hand, the expression of the pro-apoptotic protein Bax was increased after 10AB treatment. Taken together, our results suggest that 10AB-induced apoptosis is mediated through the overproduction of ROS and the disruption of mitochondrial metabolism.

Antileukemic Scalarane Sesterterpenoids and Meroditerpenoid from Carteriospongia (Phyllospongia) sp., Induce Apoptosis via Dual Inhibitory Effects on Topoisomerase II and Hsp90

“…In our previous report, 10-acetylirciformonin B, a marine sesterterpenoid analog, significantly inhibited Topo IIα activity35. Such findings encouraged us to evaluate the effect of the isolates on Topo II activity.…”

“…The assay was performed as described previously3538. Standard relaxation reaction mixtures (20 μL) containing 50 mM Tris–HCl (pH 8.0), 10 mM MgCl 2 , 200 mM potassium glutamate, 10 mM dithiothreitol, 50 μg/mL bovine serum albumin, 1 mM ATP, 0.3 μg of pHOT1 plasmid DNA, two units of human topoisomerase II (Topogen, Columbus, OH, USA), and the indicated concentrations of etoposide and the compounds were incubated at 37 °C for 30 min.…”

A novel sulfonyl chromen‐4‐ones (CHW09) preferentially kills oral cancer cells showing apoptosis, oxidative stress, and DNA damage

“…Moreover, oxidative stress‐generating drugs may induce apoptosis . Accordingly, we found that CHW09 induced ROS and apoptosis of Ca9‐22 oral cancer cells in terms of detection of annexin V and cleavage of PARP and cleavage of caspases 3/8/9, suggesting that both intrinsic and extrinsic apoptosis signaling were involved in CHW09‐induced apoptosis.…”

“…A ROS reacting agent 2′,7′‐dichlorodihydrofluorescein diacetate (H 2 DCF‐DA) (Sigma‐Aldrich; St. Louis, MO) can react with ROS and become a fluorescent molecule for flow cytometry analysis, as previously described . After drug treatment, cells were treated with 100 nM of H 2 DCF‐DA in PBS for 30 min in an incubator.…”

Tenuifolide B from Cinnamomum tenuifolium Stem Selectively Inhibits Proliferation of Oral Cancer Cells via Apoptosis, ROS Generation, Mitochondrial Depolarization, and DNA Damage

“…Mounting evidence demonstrated that ROS generation and mitochondrial membrane depolarization may lead to DNA damage [33,34,35,36,37,38] and apoptosis [38,39,40,41] in drug-treated cancer cells. Accordingly, TFB also showed a correlation between oxidative stress and DNA damage in its antiproliferative and apoptotic effects of two oral cancer cells (Ca9-22 and CAL 27) in our study.…”