A schematic overview of the cancer cell injection and drug administration schedule.

The cell suspension (100 μL/mouse, H2452; 5×10⁶ cells, MSTO; 2×10⁶ cells) was injected subcutaneously into the lower backs of mice. After 2–4 weeks, mice bearing tumors of 100–150 mm³ were randomly divided into 3 groups with 10 mice per group. Group 1 was administered PBS as control. Group 2 was injected intraperitoneally with pemetrexed (100 mg/kg) dissolved in sterile PBS on days 1–5 and 15–19. Group 3 was injected intratumorally with cSBL (2.5 mg/kg) twice per week for 4 weeks. Body weights and tumor sizes were measured twice per week. The endpoint of experiment was when the tumor diameter exceeded 200 mm³.