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Curcumin in combination with visible light inhibits tumor growth in a xenograft tumor model
Author(s) -
Dujic Jadranka,
Kippenberger Stefan,
RamirezBosca Ana,
DiazAlperi Joaquin,
BereiterHahn Jürgen,
Kaufmann Roland,
Bernd August,
Hofmann Matthias
Publication year - 2008
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.23997
Subject(s) - curcumin , apoptosis , cancer research , in vivo , curcuma , mapk/erk pathway , epidermal growth factor , cell growth , cell culture , biology , chemistry , kinase , pharmacology , microbiology and biotechnology , biochemistry , paleontology , genetics
It is known that curcumin, a dietary pigment from the plant Curcuma longa , inhibits cell proliferation and induces apoptosis in different cell lines; however, the therapeutic benefit is hampered by very low absorption after transdermal or oral application. Recent studies from our laboratory have demonstrated that curcumin at low concentrations (0.2–1 μg/ml) offered the described effects only when applied with UVA or visible light. Nevertheless, the in vivo efficacy of this combination is lacking. In the present study, we used a xenograft tumor model with human epithelial carcinoma A431 cells to test the effect of curcumin and visible light on tumor growth. It was found that tumor growth was significantly inhibited in mice that were i.p. injected with curcumin and consecutively irradiated with visible light. Furthermore, immunohistochemistry showed a reduction of Ki 67 expression, indicating a decrease of cycling cells and induction of apoptotic bodies. The effect on apoptosis was further confirmed by Western blot analysis showing enhanced activation of caspases‐9. Vice versa inhibition of extracellular regulated kinases (ERK) 1/2 and epidermal growth factor receptor (EGF‐R) was observed which may aid inhibition of proliferation and induction of apoptosis. In summary, the present findings suggest a combination of curcumin and light as a new therapeutic concept to increase the efficacy of curcumin in the treatment of cancer. © 2008 Wiley‐Liss, Inc.