Chloroquine blocks radiation-induced autophagy in NPC cells.

<p>(A) Immunoblot for LC-I and LC-II. Preincubation with chloroquine before radiation increases expression of LC-II in radiation-sensitive NPC cells 8h post treatment (B) Immunofluorescence for autophagic vacuoles. Combined treatment of chloroquine and radiation increases the formation of autophagic vacuoles 8h post treatment in cell lines CNE-2 and HNE-1. Autophagic vacuoles were examined under a fluorescence microscope at 200x and 400x magnification. (C) Flow cytometric analysis of autophagic vacuoles. Combined treatment of chloroquine and radiation increases the number of cells with autophagic vacuoles 8h post treatment in radiation-sensitive NPC cell lines. (Student’s t- test; <b>*</b> = P<0.05; <b>**</b> = P<0.01; <b>***</b> = P<0.001) (D) Transmission electron microscopy. Photomicrographs show normal nuclear and mitochondrial morphologies in untreated cells and cells treated with chloroquine. Especially, in irradiated CNE-2 and HNE-1 cells the number of autophagosomes is significantly increased 8h following radiotherapy and further augmented by pretreatment with chloroquine.