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Article
Effects of Magnolol on UVB-induced Skin Cancer Development in Mice and its Possible Mechanism of Action
BMC Cancer
  • Chandeshwari Chilampall, South Dakota State University
  • Ruth Guillermo, South Dakota State University
  • Xiaoying Zhang
  • Radhey S. Kaushik, South Dakota State University
  • Alan Young, South Dakota State University
  • David Zeman, South Dakota State University
  • Michael B. Hildreth, South Dakota State University
  • Hesham Fahmy, South Dakota State University
  • Chandradhar Dwivedi, South Dakota State University
Document Type
Article
Publication Date
10-1-2011
Abstract
Background Magnolol, a plant lignan isolated from the bark and seed cones of Magnolia officinalis, has been shown to have chemopreventive effects on chemically-induced skin cancer development. The objectives of this investigation are to study the anticarcinogenic effects of magnolol on UVB-induced skin tumor development in SKH-1 mice, a model relevant to humans, and determine the possible role of apoptosis and cell cycle arrest involved in the skin tumor development. Methods UVB-induced skin carcinogenesis model in SKH-1 mice was used for determining the preventive effects of magnolol on skin cancer development. Western blottings and flow cytometric analysis were used to study the effects of magnolol on apoptosis and cell cycle. Results Magnolol pretreated groups (30, 60 μ g) before UVB treatments (30 mJ/cm2, 5 days/week) resulted in 27-55% reduction in tumor multiplicity as compared to control group in SKH-1 mice. Magnolol pretreatment increased the cleavage of caspase-8 and poly-(-ADP-ribose) polymerase (PARP), increased the expression of p21, a cell cycle inhibitor, and decreased the expression of proteins involved in the G2/M phase of cell cycle in skin samples from SKH-1 mice. Treatment of A431 cells with magnolol decreased cell viability and cell proliferation in a concentration dependent manner. Magnolol induced G2/M phase cell cycle arrest in A431 cells at 12 h with a decreased expression of cell cycle proteins such as cyclin B1, cyclin A, CDK4, Cdc2 and simultaneous increase in the expression of Cip/p21, a cyclin-dependent kinase inhibitor. Magnolol induced apoptosis in vivo and in vitro with an increased cleavage of caspase-8 and PARP. Phospho-signal transducers and activators of transcription 3 (Tyr705), B-Raf, p-MEK, and p-AKT were down-regulated, whereas phosphorylation of ERK was induced by magnolol in A431 cells. Conclusions Magnolol pretreatments prevent UVB-induced skin cancer development by enhancing apoptosis, causing cell cycle arrest at G2/M phase, and affecting various signaling pathways. Magnolol could be a potentially safe and potent anticarcinogenic agent against skin cancer.
Pages
17
Type
text
Language
en
DOI of Published Version
10.1186/1471-2407-11-456
Publisher
BioMed Central
Rights
Copyright © 2011 Chilampalli et al;
Creative Commons License
Creative Commons Attribution 3.0
Citation Information
Chilampalli, S., R. Guillermo, X. Zhang, R.S. Kaushik, A. Young, D. Zeman, M. Hildreth, F. Hesham, and C. Dwivedi. 2011. Effects of magnolol on UVB-induced skin cancer development in mice and its possible mechanism of action, BMC Cancer. 11:456. doi: 10.1186/1471-2407-11-456.