Analysis of Osmotic Pump-Administered Xylitol in a Syngeneic Mouse Melanoma Model

The present study used a syngeneic mouse model of malignant melanoma to evaluate the inhibitory efficacy of continuous xylitol administration via a subcutaneous osmotic minipump. The B16F10 syngeneic model for malignant melanoma consisted of 6–8-week-old C57BL/6 male mice subcutaneously injected with 5 × 105 B16F10 cells suspended in 100 μL PBS in the right flank. The mice were randomly assigned to two groups: Group 1 was the treatment group, which received 10% w/v xylitol in saline-loaded pumps (n = 10), while Group 2 was the control group, which received saline-loaded pumps (n = 10). ALZET 2004 minipumps were implanted subcutaneously in the left flank of B16F10-injected mice once more than 50% of all mice developed palpable tumors. After pump implantation surgery, the mice were monitored daily and weighed 2–3× times per week. Tumor sizes were measured with calipers 2–3× per week, and all mice were euthanized when their tumors became too large (20 mm on any axis or 2000 mm3). The tumor size growth was reduced by approximately 35% by volume in the xylitol-treated group which was not statistically significant. The xylitol group had a longer survival time, but this was not statistically significant (Kaplan–Meier), as was the case with the survival analysis by the Cox proportional hazards model. The metabolomic analysis suggests that xylitol significantly alters the tumor’s metabolism, potentially affecting the host immune response.