Male BALB/c nude mice, aged 5 weeks, were procured from Guangzhou Ruige biology Model Animal Research Center (No. 44827200001656, Guangzhou, China). Tumor xenograft assay was performed by dissolving SP2/0 cells in PBS (1 x 10⁶/200 uL) and subcutaneously inoculating them into the right flank of mice. After the tumor reached 50 mm³, the tumor-bearing mice were randomly separated into three groups and intraperitoneally administered with NC (4.6 or 6 mg/kg) every two days. Body masses and tumor sizes were determined every day. Subsequently, the mice were sacrificed, and the inhibition of tumor growth and the tumor masses were determined. Later, visceral organs and tumors from every group were harvested and immobilized in paraformaldehyde (4%). All murine experimental procedures conformed to the National Institute of Health Guide for the Care and Use of Laboratory Animals.