Pyrrocidine A, a metabolite of endophytic fungi, has a potent apoptosis-inducing activity against HL60 cells through caspase activation via the Michael addition.
Pyrrocidine A is a known antimicrobial compound produced by endophytic fungi and has a unique 13-membered macrocyclic alkaloid structure with an α,β-unsaturated carbonyl group. We have previously reported that pyrrocidine A shows potent cytotoxicity against human acute promyelocytic leukemia HL60 cells, and the activity is 70-fold higher than that of pyrrocidine B which is the analog lacking the α,β-unsaturated carbonyl group. Pyrrocidine A induced nuclear condensation, DNA fragmentation and caspase activation in HL60 cells. Since the DNA fragmentation was suppressed by pretreatment with the pan-caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp (OMe) fluoromethylketone (z-VAD-fmk), caspase-mediated apoptosis contributes to pyrrocidine A-induced cytotoxicity. JFCR39 human cancer cells panel indicated that the mechanism of action of pyrrocidine A is different from other clinical anticancer drugs, and this compound broadly inhibited the growth of various cancer cell lines. The apoptosis induction by pyrrocidine A was suppressed by both N-acetyl-l-cysteine (NAC) and glutathione, both of which are thiol-containing antioxidants. Furthermore, pyrrocidine A directly bound to N-acetyl-l-cysteine methyl ester (NACM) through the Michael-type addition at the α,β-unsaturated carbonyl group and was detected by HPLC and liquid chromatography-ESI-tandem MS (LC-ESI-MS/MS) analyses. This indicates that this moiety is crucial for the potent apoptosis-inducing activity of pyrrocidine A.
The United Graduate School of Agricultural Sciences, Iwate University, Iwate, Japan.
Shota
S
Uesugi
Graduate School of Agriculture, Iwate University, Iwate, Japan.
Nozomi
N
Fujisawa
Center for Liberal Arts and Sciences, Iwate Medical University, Iwate, Japan.
Jun
J
Yoshida
National Agricultural Research Center for Tohoku Region (NARCT), Iwate, Japan.
Mitsuru
M
Watanabe
Division of Molecular Pharmacology, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Tokyo, Japan.
Shingo
S
Dan
Division of Molecular Pharmacology, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Tokyo, Japan.|Center for Product Evaluation, Pharmaceuticals and Medical Device Agency, Tokyo, Japan.
Takao
T
Yamori
Faculty of Agriculture, Yamagata University, Yamagata, Japan.
Yoshihito
Y
Shiono
The United Graduate School of Agricultural Sciences, Iwate University, Iwate, Japan.|Graduate School of Agriculture, Iwate University, Iwate, Japan.
Ken-ichi
K
Kimura
D000111:Acetylcysteine / Q000494:pharmacology; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001952:Bridged-Ring Compounds / Q000494:pharmacology*; D061945:Caspase Inhibitors / Q000494:pharmacology; D053938:DNA Fragmentation / Q000187:drug effects; D018922:HL-60 Cells; D006801:Humans; D006999:Hypocreales / Q000737:chemistry; D009842:Oligopeptides / Q000494:pharmacology; D011760:Pyrrolidinones / Q000494:pharmacology*; D017382:Reactive Oxygen Species; D053719:Tandem Mass Spectrometry
D000590:Amino Acid Chloromethyl Ketones; D000890:Anti-Infective Agents; D000970:Antineoplastic Agents; D001952:Bridged-Ring Compounds; D061945:Caspase Inhibitors; D009842:Oligopeptides; D011760:Pyrrolidinones; D017382:Reactive Oxygen Species; C517629:benzyloxycarbonyl-valyl-alanyl-aspartic acid; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C508751:pyrrocidine A; C508752:pyrrocidine B; D000111:Acetylcysteine