Figure 6.

Autophagy inhibition sensitizes tumors to radiation in vivo. (A) Treatment with a combination of radiation and 3-MA reduced the growth of EC9706 human esophageal squamous cell carcinoma cell line xenografts. (B) Representative images of tumors and tumor slides subjected to TUNEL as well as H&E staining (magnification, ×400). Tumor size was decreased following treatment with 3-MA and radiation alone, and tumor size was smallest in the radiation + 3-MA group. (C) TUNEL-positive cells were quantified, showing increased numbers of apoptotic cells in single treated and significantly higher increases in the number of apoptotic cells in the combined treatment group. Results are expressed as the number of TUNEL-positive cells/field counted (five random fields per slide from a total of five slides per study group). (D) Western blot analysis of autophagic indicators LC-3 and beclin-1; proliferative indicators PCNA and Ki-67; and Bax and Bcl-2 apoptotic proteins in the xenografts. 3-MA, 3-methyladenine; IR, ionizing radiation; LC3, microtubule-associated protein light chain 3; PCNA, proliferating cell nuclear antigen; Bcl-2; B-cell lymphoma 2; Bax, Bcl-2-associated X protein; H&E, hematoxylin & eosin; TUNEL, terminal deoxynucleotidyl transferase dUTP nick end labeling.