Ling Zhi-8, a fungal immunomodulatory protein in Ganoderma lucidum, alleviates CPT-11-induced intestinal injury via restoring claudin-1 expression.

CPT-11 (Irinotecan) remains an important chemotherapeutic agent against various solid tumors nowadays. Potential adverse effects, especially gastrointestinal toxicities, are the main limiting factor for its clinical utility. Ling Zhi-8 (LZ-8), a fungal immunomodulatory protein in Ganoderma lucidum mycelia, has potential for drug development due to its multiple bioactivities and functions. This study aimed to explore the influence of LZ-8 on CPT-11-treated IEC-6 cells in vitro and on mice with CPT-11-induced intestinal injury in vivo. The mechanism through which LZ-8 exerted its protective effects was also investigated. In the in vitro study, the viability and claudin-1 expression of IEC-6 cells decreased gradually with increasing concentrations of CPT-11, but LZ-8 treatment had no obvious influence on their viability, morphology, and claudin-1 expression. Pretreatment of LZ-8 significantly improved CPT-11-decreased cell viability and claudin-1 expression in IEC-6 cells. In mice with CPT-11-induced intestinal injury, LZ-8 treatment could ameliorate symptoms and mitigate intestinal damage. Meanwhile, LZ-8 restored claudin-1 expression in the intestinal membranes in CPT-11-treated mice. Collectively, our results demonstrated the protective effects of LZ-8 against CPT-11 damage in both IEC-6 cells and mice. LZ-8 can restore claudin-1 expression in intestinal cells following CPT-11 treatment, suggesting the role of claudin-1 in the scenario.