Within the last decade, extensive research has revealed that curcumin can increase the sensitivity of tumor cells
to high-energy X-ray radiation in vitro and dual-specificity phosphatase (DUSPs) are implicated in cancer, obesity,
diabetes, inflammation and Alzheimer’s disease. To date, the article about the radiosensitizing effect of curcumin via
enhancement of the DUSP-2 pathway was rarely reported. Here, we discuss the radiosensitizing effects of curcumin on
suppressing glioma vivo growth. BALB-c nude mice bearing subcutaneous U87 xenografts were treated with curcumin
and/or local radiation to assess their vivo response. Tumor growth, real-time PCR, western blotting, immunohistochemical
assay and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) were performed to explore
the possible mechanism involved. Curcumin in combination with irradiation significantly enhanced the tumor-suppressive
effect in vivo compared with local radiotherapy alone. Both mRNA and protein levels of DUSP-2 were significantly
upregulated in the curcumin in combination with radiation treatment group. Curcumin pretreatment inhibited radiationinduced
extracellular signal-regulated kinases (ERK)/c-Jun N-terminal kinases (JNK) phosphorylation and enhanced
radiation-induced tumor cell apoptosis in subcutaneous xenografts. In conclusion, curcumin significantly increased the
radiosensitivity of U87 human glioma cells in vivo. The radiosensitizing effect of curcumin was found to be closely
related to its pro-apoptosis activity via enhancement of the DUSP-2 pathway.
Keywords: Apoptosis, curcumin, dual specificity phosphatase 2, glioma, radiosensitization.
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