Diarylheptanoids derived from Alpinia officinarum induce apoptosis, S-phase arrest and differentiation in human neuroblastoma cells.
BACKGROUND
We have previously screened many natural products for their cytotoxic effects on neuroblastoma cell lines, and two diarylheptanoids derived from Alpinia officinarum, 7-(4''-hydroxy-3''-methoxyphenyl)-1-phenyl-4E-hepten-3-one (Compound 1) and (5R)-5-methoxy-7-(4''-hydroxy-3''-methoxyphenyl)-1-phenyl-3-heptanone (Compound 2), were shown to have potent cytotoxicity. On this basis, a detailed study of the antitumor activities of these two diarylheptanoids in neuroblastoma cell lines was performed.


METHODS
Cytotoxicity was assessed by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. To measure apoptosis, nuclear shrinkage was monitored by Hoechst 33342 staining, and activation of caspases 3 and 9 was monitored by Western blotting. Cell cycle status was evaluated by flow cytometry with propidium iodide staining. Differentiated cells were photographed and counted in a randomized fashion.


RESULTS
Both diarylheptanoids showed significant cytotoxicity against neuroblastoma cell lines (IMR-32, SK-N-SH, NB-39). The compounds induced nuclear shrinkage and fragmentation, and activated caspase-3 and caspase-9. Flow cytometric analysis revealed induction of S-phase cell cycle arrest concurrently with an increased sub-G(1) cell population. Moreover, a low concentration (10(-8) M) of Compound 1 induced significant neurite branching in the NB-39 cell line.


CONCLUSIONS
Diarylheptanoids derived from A. officinarum have marked activity against neuroblastoma cells, acting through multiple mechanisms. Our results suggest that the two compounds studied here may be useful for the treatment of patients with neuroblastoma.
Tabata
Keiichi
K
Research Unit of Clinical Medicine, College of Pharmacy, Nihon University, 7-7-1 Narashinodai, Funabashi-shi, Chiba 274-8555, Japan. tabata.keiichi@nihon-u.ac.jp
Yamazaki
Yumiko
Y
Okada
Mari
M
Fukumura
Kazutaka
K
Shimada
Atsushi
A
Sun
Yi
Y
Yasukawa
Ken
K
Suzuki
Takashi
T
D032429:Alpinia / Q000737:chemistry*; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects*; D045744:Cell Line, Tumor; D036381:Diarylheptanoids / Q000494:pharmacology*; D005434:Flow Cytometry; D006801:Humans; D009447:Neuroblastoma / Q000473:pathology; D016196:S Phase / Q000187:drug effects*
D000972:Antineoplastic Agents, Phytogenic; D036381:Diarylheptanoids; D053148:Caspase 3; D053453:Caspase 9