Neoplasma Vol.69, No.4, p.807–819, 2022

This article reported the mechanism of anlotinib in gastric cancer treatment. Gastric cancer cells were treated with anlotinib (8 μM) and transfected by STING shRNA and STING vectors. Cell counting kit-8 assay, wounding healing assay, and Transwell experiment were applied for proliferation, migration, and invasion detection. PD-L1 fluorescence intensity in gastric cancer cells was explored by flow cytometry. IFN-β level was researched by enzyme-linked immunosorbent reaction. Xenograft tumor experiment was performed by administering mice with anlotinib and anti-PD-L1 antibody. Immunohistochemistry and western blot were used for proteins expression detection. Quantitative real-time reverse transcription-polymerase chain reaction was applied for mRNA expression detection. Hematoxylin and eosin staining was conducted on lung, liver, kidney, and cerebral cortex of mice. Gastric cancer cells treated with anlotinib exhibited reduced proliferation, migration, and invasion (p < 0.01).

Anlotinib treatment reduced PCNA, CDK1, and MMP2 protein expressions and increased E-cadherin protein expression in gastric cancer cells (p < 0.01). Anlotinib treatment suppressed PD-L1 expression and activated the cGAS-STING/IFN-β pathway in gastric cancer cells (p < 0.01). STING knockdown partially reversed the inhibition of anlotinib on gastric cancer cells proliferation, migration, invasion, and immune escape (p < 0.05 or p < 0.01). However, STING overexpression exhibited the opposite effect. Anlotinib synergistically improved anti-tumor efficacy of anti-PD-L1 in vivo. Anlotinib synergistic anti-PD-L1 increased CD3+, CD8+ T cells, and activated the cGAS-STING/IFN-β pathway in xenograft tumor. Anlotinib was non-toxic to lung, liver, cortex, and kidney. Anlotinib suppressed gastric cancer cells proliferation, migration, and immune escape by activating the cGAS-STING/IFN-β pathway.