ABSTRACT
To investigate the effects of autophagy activator and autophagy inhibitor on the CNE2 radiation sensitivity of nasopharyngeal carcinoma cells. RNA interference technology was used to silence the atg5 gene and autophagy inhibition cell model was constructed. Rapamycin and chloroquine were treated respectively on cells with X-ray 5Gy irradiation. Cells' growth status were observed for 8 days and control group was set. The cell viability was detected by MTT assay and colony formation assay, and the cell cycle was analyzed by flow cytometry. Compared with the control group, the survival rate, clone formation rate and the survival rate of the irradiation of the other three groups were significantly lower. (P<0.05) Most cells were detected in the G0/G1 phase in the other three groups except the control group, and cells of the other two periods were less than those in the G0/G1 phase. The autophagy inhibitor or activator and atg5 silencing can be increased by CNE2 radiation therapy, however, the sensitization effect increase of autophagy activator is better than others.
Subject(s)
Autophagy/radiation effects , Gamma Rays , Radiation Tolerance/radiation effects , Autophagy/drug effects , Autophagy-Related Protein 5/antagonists & inhibitors , Autophagy-Related Protein 5/genetics , Autophagy-Related Protein 5/metabolism , Cell Line, Tumor , Cell Survival/drug effects , Chloroquine/toxicity , Flow Cytometry , G1 Phase Cell Cycle Checkpoints/drug effects , G1 Phase Cell Cycle Checkpoints/radiation effects , Humans , RNA Interference , RNA, Small Interfering/metabolism , Radiation Tolerance/drug effects , Sirolimus/toxicityABSTRACT
Changes in the protein secondary structure and electron transport activity of the Triton X-100-treated photosystem I (PSI) and photosystem II (PSII) complexes after strong illumination treatment were studied using Fourier transform-infrared (FT-IR) spectroscopy and an oxygen electrode. Short periods of photoinhibitory treatment led to obvious decreases in the rates of PSI-mediated electron transport activity and PSII-mediated oxygen evolution in the native or Triton-treated PSI and PSII complexes. In the native PSI and PSII complexes, the protein secondary structures had little changes after the photoinhibitory treatment. However, in both Triton-treated PSI and PSII complexes, short photoinhibition times caused significant loss of alpha-helical content and increase of beta-sheet structure, similar to the conformational changes in samples of Triton-treated PSI and PSII complexes after long periods of dark incubation. Our results demonstrate that strong-light treatment to the Triton-treated PSI and PSII complexes accelerates destruction of the transmembrane structure of proteins in the two photosynthetic membranes.
