Dendrobine Suppresses Tumor Growth by Regulating the PD-1/PD-L1 Checkpoint Pathway in Lung Cancer

BACKGROUND: Dendrobine is a bioactive alkaloid isolated from Dendrobium nobile. Studies have evaluated the anti-tumor effect of dendrobine in cancers, including lung cancer. However, the mechanism of dendrobine inhibiting tumors requires further study. METHODS: Bioinformatics was performed to screen the potential targets of dendrobine. The intersection of dendrobine and lung cancer targets was performed for KEGG analysis. CCK-8 was used to detect cell viability after dendrobine treatment. A xenograft mouse model was established to explore the effect of dendrobine on lung cancer. The percentages of PD-L1+, CD4+, CD8+, CD11b+, CD25+FOXP3+ cells, the expression of Ki-67 and caspase-3, the expression of pathway-related proteins, the levels of IL-2, IFN-γ, and TGF-β, and the changes of indicators of liver and renal function were measured. RESULTS: Dendrobine regulated the PD1/PD-L1 checkpoint signaling pathway and affected the occurrence and development of lung cancer. Dendrobine decreased the cell viability of lung cancer. Dendrobine and anti-PD-L1 decreased tumor growth, increased caspase-3 expression, and reduced Ki-67 expression in tumor tissues. Dendrobine and anti-PD-L1 suppressed protein expression of PD-L1, p-JAK1/JAK1, and p-JAK2/JAK2 in tumor tissues. Greatly, dendrobine and anti-PD-L1 decreased the percentages of PD-L1+, CD11b+, and CD25+FOXP3+ cells, increased the percentages of CD4+ and CD8+cells, and enhanced the levels of IL-2, IFN-γ, and TGF-β in tumor tissues. Dendrobine demonstrated no hepatorenal toxicity to the tumor mice. The combination of dendrobine and anti-PD-L1 greatly strengthened the effects of dendrobine on tumors. CONCLUSION: Dendrobine inhibited tumor immune escape by suppressing the PD-1/PD-L1 checkpoint pathway, thus restricting tumor growth of lung cancer.