Ginsenoside F4 inhibits colorectal cancer progression by boosting dendritic cell maturation and remodeling the tumor microenvironment.

Background: Immunotherapy that employs dendritic cells (DCs) to activate the patient's immune system has emerged as a promising therapeutic strategy to combat cancer; however, effective targeting agents are still limited. Ginsenoside F4, as a rare ginsenoside found in Panax ginseng, exhibits stronger antitumor and immunomodulatory activities than primary ginsenosides. However, its therapeutic effects on various diseases remain limited.

Aim: To investigate the antitumor effect of Ginsenoside F4 and mechanism on the maturation of DCs in colorectal cancer (CRC).

Methods: The changes in mature DC markers and cytokines generated after DCs were exposed to F4 were assessed using flow cytometry and enzyme-linked immunosorbent assay, respectively. The viability of CRC CT26 cells co-cultured with T lymphocytes was monitored by cell counting kit-8 assay. Furthermore, the histopathological characteristics and immune cell infiltration in tumor tissues of CT26-bearing mice were analyzed by hematoxylin-eosin and immunofluorescent staining. The expressions of apoptosis-relative proteins were detected by western blot assay.

Results: Treatment with F4 promoted the maturation of DCs, elevated the expressions of cluster of differentiation (CD) 83 and CD86, increased the secretion of interleukin (IL)-2, IL-10, and IL-12 p70, and upregulated the expressions of phosphorylated phosphoinositide 3-kinase, phosphorylated protein kinase B, and nuclear factor kappa-B (NF-κB) phosphorylated p65 in DCs, which enhanced antigen-specific CD8+ T-cell responses. However, these benefits could be reversed by the sphingosine-1-phosphate 1 (S1PR1) inhibitor fingolimod hydrochloride. Furthermore, oral administration with F4 inhibited tumor growth and increased DC and CD8+ T-cell infiltration in the tumor tissues of CT26-bearing mice.

Conclusion: The results demonstrated that F4 inhibited the growth of CRC by maturing DCs through activating S1PR1-mediated phosphoinositide 3-kinase/protein kinase B and NF-κB pathways, which triggered the antitumor effects of CD8+ T cells. Therefore, F4 could serve as an antitumor immunomodulator for CRC treatment.