Magnolol-Induced H460 Cells Death via Autophagy but Not Apoptosis

다국어 초록 (Multilingual Abstract)

We have reported that the protective effect of Magnolol on TBHP-induced injury in human nonsmall
lung cancer H460 cells is partially via a p53 dependent mechanism. In this study, we
found that Magnolol displayed a stimulatory effect at low concentrations (≤20 µM) whilst inhibitory
effect at high concentrations (≥40 µM) in H460 cells. To investigate the mechanism of
inducing the biphasic effect in H460 cells with Magnolol, we showed that Magnolol stimulated
DNA synthesis at low concentrations and displayed an inhibition effect at high concentrations
in H460 cells. More importantly, the inhibition of DNA synthesis was accompanied by the S
phase cell cycle arrest and the appearance of intense intracytoplasmic vacuoles. These vacuoles
can be labeled by autophagic marker monodansylcadaverin (MDC), 3-methyladenine (3-
MA), an inhibitor of autophagy, was able to inhibit the occurrence of autophagy. The results of
the LDH activity assay and TUNEL assay also showed that Magnolol at high concentrations
inhibiting H460 cell growth was not via apoptotic pathway. Furthermore, accompanied by the
occurrence of autophagy, the expression of phospho-Akt was down-regulated but PTEN significantly
was up-regulated. In conclusion, Magnolol induces H460 cells death by autophagy but
not apoptotic pathway. Blockade of PI3K/PTEN/Akt pathway is maybe related to Magnololinduced
autophagy. Autophagic cells death induction by Magnolol underlines the potential utility
of its induction as a new cancer treatment modality.

참고문헌 (Reference)

1 "specific inhibitor of autophagic/lysosomal protein degradation in isolated rat hepatocytes" 3-, 1889-18921982

2 "role in hepatocarcinogenesis and subtypes" 669-675, 1994

3 "Vascular endothelial growth factor induces expression of the antiapoptotic pro-teins Bcl-2 and A1 in vascular endothelial cells" 273 : 13313-13316, 1998

4 "The tumor suppresor PTEN positively regulates macroautophagy by inhibiting the Magnolol-induced H460 Cells Death via Autophagy but Not Apoptosis 1573 phosphatidylinositol 3-kinase/protein kinase B pathway" 276 : 35243-35246, 2001

5 "The pleiotropic role of autophagy: from protein metabolism to bactericide" 12 : 1535-1541, 2005

6 "The Pten/PI3K pathway governs the homeostasis of V{alpha}14iNKT cells" 109 : 3316-3324, 2007

7 "Studies on the mechanisms of autophagy formation of the autophagic vacuole" 1923-19331990

8 "Studies on inhibitors of skin tumor promotion Neolignans from Magnolia officinalis" ko nishi (ko nishi): 816-822, 1991

9 "Silencing mammalian target of rapamycin signaling by small interfering RNA enhances rapamycin-induced autophagy in malignant glioma cells" 26 : 1840-1851, 2007

10 "Requirement of phosphoinositide 3-kinase and Akt for interferon-beta-mediated induction of the beta-R1 (SCYB11) gene" 277 : 38456-38461, 2002

11 "Protective Effect of Magnolol on TBHP-Induced Injury in H460 Cells Partially via a p53 Dependent Mechanism (inpress). ikeda, K. and Nagase, H., Magnolol has the ability to induce apoptosis in tumor cells" 25 : 1546-1549, 2002

12 "Programmed cell death during metamorphosis in the blow-fly Calliphora vomitoria" 34 : 202-217, 1996

13 "Monodansyl-cadaverine (MDC) is a specific in vivo marker for autophagic vacuoles" 66 : 3-14, 195

14 "Molecular mechanisms of apoptosis induced by magnolol in colon and liver cancer cells" 32 : 73-83, 2001

15 "Magnolol suppresses proliferation of cultured human colon and liver cancer cells by inhibiting DNA synthesis and activating apoptosis" 84 : 532-544, 2002

16 "Magnolol reduces myocardial ischemia/reper-fusion injury via neutrophil inhibition in rats" 422 : 159-167, 2001

17 "Magnolol alters the course of endotoxin tolerance and provides early protection against endotoxin challenge following sublethal hemorrhage in rats" 22 : 358-363, 2004

18 "Inhibition of autophagy abrogates tumour necrosis factor alpha induced apoptosis in human T-lymphoblastic leukaemic cells" 98 : 673-685, 1997

19 "Effects of natural prenylated flavones in the phenotypical ER (+) MCF-7 and ER (-) MDA-MB-231 human breast cancer cells" 164 : 24-36, 2006

20 "Distinct classes of phosphatidylinositol 3'-kinases are involved in si gnaling pathways that control macroautophagy in HT-29 cells" 275 : 992-998, 2000

21 "Death without caspases, caspases without death" 14 : 184-192, 2004

22 "Crystal structure of the PTEN tumor suppressor: implications for its phosphoinositide phosphatase activity and membrane association" 99 : 323-334, 1999

23 "Autophagy in neurons: a review" 17 : 897-908, 2002

24 "Autophagy as a cell death and tumor suppressor mechanism" 23 : 2891-2906, 2004

25 "Autophagy and signaling: their role in cell survival and cell death" 12 : 1509-1518, 2005

26 "Antimicrobial activity of phenolic constituents of Magnolia grandiflora L" 951-952, 1981

27 "Antimicrobial activity of magnolol and honokiol against periodontopathic microorganisms" 64 : 367-369, 1998

28 "Analyses of Galpha-interacting protein and activator of G-protein-signaling-3 functions in macroautophagy" 390 : 17-31, 2004

29 "Amino acids interfere with the ERK1/2-dependent control of macroautophagy by controlling the activation of Raf-1 in human colon cancer HT-29 cells" 278 : 16667-16674, 2003

30 "Akt/protein kinase B is constitutively active in non-small cell lung cancer cells and promotes cellular survival and resistance to chemotherapy and radiation" 61 : 3986-3997, 2001

31 "Active cell death induced by the anti-estrogens tamoxifen and ICI 164 384 in human mammary carcinoma cells (MCF-7) in culture: the role of autophagy" 17 : 1595-1607, 1996