Combination of radiotherapy and Anlotinib enhances benefit from immunotherapy to liver metastasis and abscopal tumor from lung cancer

Many studies have shown that liver metastasis can weaken the efficacy of immunotherapy. Immunotherapy combined with radiotherapy or anti-angiogenic therapy has been proven to have synergistic anti-tumor effects. So we devote to explore whether the combination of the three therapies can exert effective anti-tumor effects on liver metastasis. The clinical information of 118 patients with liver metastasis were collected to compare the intrahepatic progression-free survival between immunotherapy and immunotherapy combined with other treatments. We used Lewis lung cancer (LLC) cell to establish a mouse liver metastasis tumor model and record tumor burden and survival. Tumor-infiltrating immune cells detected by flow cytometry. RNA sequencing was performed and the proportion of immune cells were analyzed by TIMER2.0 database. Compared with immunotherapy group, the combination therapy group showed a trend for longer median intrahepatic progression-free survival. Radiotherapy combined with PD-1 inhibitor and Anlotinib can inhibit liver metastasis and subcutaneous tumor growth and prolong the survival compared with other groups in vivo. Compared with the anti-PD-1 treatment group, triple therapy can increase CD4+T, CD8+T, and IFN-γ+CD8+T cells and decrease infiltration of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) in tumors. PPAR signaling pathway were significantly activated and CD8+T and dendritic cells (DC) were increased in the triple therapy group compared to the PD-1 inhibitor combined with Anlotinib group. Radiotherapy combined with PD-1 inhibitor and Anlotinib can effectively exert anti-tumor efficacy and reshape the tumor immune microenvironment by increasing the infiltration of anti-tumor immune cells and reducing the infiltration of immunosuppressive immune cells.