Résumé
OBJECTIVE: To investigate the radiosensitizing effect of PP2A inhibition on nasopharyngeal carcinoma cells and its xenografts. METHODS: Co-immunoprecipitation and flow cytometry were used to examine PP2A activity, cell cycle analysis and apoptosis of CNE1 and its xenografts, in order to explore the effect of radiosensitization in CNE1 cells. RESULTS: Cell cycle distribution and apoptosis were measured by flow cytometry 24 h after treatment. The combination of 8 Gy and 40 μmol < L-1 norcantharidin produced significantly accumulation of cells in G2/M-phase( 45.71 ±2.015)% and more apoptosis(75.63 ± 6.11)% in CNE1 cell lines compared with norcantharidin alone and to radiation alone, norcantharidin in combination with radiation produced the greatest effects on tumor growth slowing and decreasing tumor weight by 87.64% relative to vehicle in CNE1 xenografts. Our data demonstrate that inhibition of PP2 A with radiation significantly sensitizes nasopharyngeal carcinoma cell lines in vitro and in vivo. CONCLUSION: The inhibition of PP2A with norcantharidin inhibited xenograft growth obviously. Our results support further exploration of PP2A inhibition as part of radiotherapy regimens for NPC and potentially other solid tumors.