Gambogic acid enhances the radiosensitivity of human esophageal cancer cells by inducing reactive oxygen species via targeting Akt/mTOR pathway

• DOI: 10.1007/s13277-015-3974-1
• Publication Date: 2015-08-29T05:41:46Z
• Authors: Yan Yang; Xiangdong Sun; Yuehua Yang; Xi Yang; Hongcheng Zhu; Shengbin Dai; Xiaochen Chen; Hao Zhang; Qing Guo; Yaqi Song; Feng Wang; Hongyan Cheng; Xinchen Sun
• Keywords: Radiosensitivity; Viability assay; Clonogenic assay; Gambogic acid

Radiotherapy is a widespread treatment in human solid tumors. However, therapy resistance and poor prognosis are still problems. Gambogic acid (GA), extracted from the dried yellow resin of gamboges, has an anticancer effect against various types cancer cells. To explore radiosensitivity GA on esophageal cell line TE13, viability was tested by Cell Counting Kit-8 (CCK-8) assay, colony formation assay used to assess effects flow cytometry performed meter percentage apoptosis. The protein levels microtubule-associated 1 light chain 3 (LC3), caspase3, caspase8, casepase9, pAkt, p-mammalian target rapamycin (p-mTOR) were using Western blot. distribution LC3 detected immunofluorescence. Additionally, we also examined reactive oxygen species (ROS) expression laser scanning confocal microscope (LSCM). cells transfected with adenovial vector monitor autophagy through green fluorescent (GFP-red fluroscent (RFP)-LC3. rates apoptotic combined-treated TE13 increased significantly compared control groups accordance results clonogenic survival showed that enhances sensitizing enhancement ratio (SER) 1.217 1.436 at different concentrations. LC3-II level combined group indicating increase incidence, GFP-RFP-LC3 experiment may block process autophagic flux Moreover, successfully demonstrated ROS involved induction autophagy. ROS-mediated depends inhibition Akt/mTOR pathway. Taken together, induced involves apoptosis which regulated hypergeneration inhibition.