Fig. 1. Survival curves of A549 cell in invitro test: (a) cell survival rate in different glucose concentrations medium under aerobic condition; (b) cell survival rate in different glucose concentrations medium under anaerobic condition

Fig. 2. Curves of tumor volume of mice along with time (at 42 d, the sequence from high to low is the group of A_m, B_m, C_m, D_m, E_m）

Fig. 3. Results of tracer in mice tumor area (at 6 min, the sequence from high to low is the group of A_m, B_m, C_m, D_m, E_m)

Fig. 4. HE staining of tumor tissues of mice in each group (×400): (a) control group; (b) metformin alone group; (c) radiotherapy alone group; (d) metformin 1 h before radiotherapy group; (e) metformin 24 h after radiotherapy group