Melittin radiosensitizes esophageal squamous cell carcinoma with induction of apoptosis in vitro and in vivo
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Currently, unresectable esophageal squamous cell carcinoma (ESCC) is primarily treated by chemoradiotherapy. However, the outcome has not improved significantly because of radioresistance of cancer cells. This study aimed to determine the radiosensitizing effect of melittin, a novel component of bee venom, in ESCC. ESCC cell lines were irradiated with or without melittin. Cell proliferation was detected by Cell Counting Kit 8 assay. Radiosensitization was evaluated by clonogenic survival assay. Cell apoptosis was detected by flow cytometry. Results show that melittin potently sensitized ESCC cells to radiation with a sensitization enhancement ratio of 1.15–1.42. Radiosensitization was accompanied with enhanced apoptosis and regulated by apoptosis proteins. The results were confirmed by in vivo studies on tumor-bearing xenografts. In summary, these results provide support that melittin may be a potentially promising radiosensitizer in ESCC radiation therapy.
KeywordsMelittin Esophageal squamous cell carcinoma Radiosensitivity Apoptosis
This work was supported by the Natural Science Foundation of China (no. 81272504), Research and Innovation Project for College Graduates of Jiangsu Province (no. CXZZ12_0588), Innovation Team (no. LJ201123 (EH11)), A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD; JX10231801), grants from Key Academic Discipline of Jiangsu Province “Medical Aspects of Specific Environments,” Six Major Talent Peak Project of Jiangsu Province (2013-WSN-040), Jiangsu Provincial Science and Technology Projects (BK2011854 (DA11)), and “333” Project of Jiangsu Province (BRA2012210 (RS12)).
Conflicts of interest
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