Fig. 4: ICAM1 overexpression reactivated the TME and sensitized anti-PD-1 immunotherapy in Lkb1 deficient lung tumors.

a Total CD8⁺ T cells relative to CD45⁺ cells in tumor tissue, relative mean fluorescence intensity (MFI) of CD69 and CD44 on CD8⁺ T cells, percentage of CD62L⁺CD44⁺ (central memory T cells) and CD62L⁻CD44⁺ (effector memory T cells) in CD8⁺ T cells, and total NK cells relative to CD45⁺ cells in tumor tissue and relative MFI of CD69 on NK cells from mice bearing LLC1 tumors (LLC1-shControl-Icam1^WT, LLC1-shLkb1-Icam1^WT, LLC1-shLkb1-Icam1^OE) were analyzed by flow cytometry. n = 1 independent experiment. CD8⁺ T-cell, n = 13 in shControl-Icam1^WT, n = 8 in shLkb1-Icam1^WT, n = 16 in shLkb1-Icam1^OE; *p = 0.0193. CD69, n = 12 in shControl-Icam1^WT, n = 6 in shLkb1-Icam1^WT, n = 9 in shLkb1-Icam1^OE; *p = 0.0436. CD44, n = 5 samples in each group. Effector memory, n = 5 samples in each group. Central memory, n = 5 in shControl-Icam1^WT, n = 7 in shLkb1-Icam1^WT, n = 6 in shLkb1-Icam1^OE. NK cells, n = 7 in shControl-Icam1^WT, n = 6 in shLkb1-Icam1^WT, n = 5 in shLkb1-Icam1^OE; *p = 0.0415. CD69, n = 10 in shControl-Icam1^WT, n = 5 in shLkb1-Icam1^WT, n = 7 in shLkb1-Icam1^OE; *p = 0.0333. b LLC1-shLkb1-Icam1^WT or LLC1-shLkb1-Icam1^OE luc cells were injected into the left chest of mice and tumor formation was detected using a bioluminescence imager every week. Bioluminescent images in mice bearing lung tumors treated with isotype and anti-PD-1. c Quantification of bioluminescence results. n = 3 in Icam1^WT receiving IgG, n = 5 in Icam1^WT receiving anti-PD-1 Ab, n = 4 in Icam1^OE receiving IgG, n = 5 in Icam1^OE receiving anti-PD-1 Ab. *p = 0.0477. d C57BL/6 mice were subcutaneously inoculated with Lewis lung cancer cells with Lkb1 knockdown and stably Icam1 overexpression (Icam1^OE) or its parental (Icam1^WT) cell line. They were administered with different treatments (control immunoglobulin G (IgG), or anti-PD-1 Ab). Tumor size (left, n = 6 in Icam1^WT receiving IgG, n = 5 in Icam1^WT receiving anti-PD-1 Ab, n = 9 in Icam1^OE receiving IgG, and n = 8 in Icam1^OE receiving anti-PD-1 Ab. ***p = 0.0006.) and survival (right, n = 8 in Icam1^WT receiving IgG, n = 6 in Icam1^WT receiving anti-PD-1 Ab, n = 8 in Icam1^OE receiving IgG, and n = 8 in Icam1^OE receiving anti-PD-1 Ab. p = 0.0079) in different treatment arms were monitored. Kaplan–Meier curves of progression-free survival according to the expression level of ICAM1 in lung adenocarcinoma patients (e GSE126044 and GSE135222, n = 56 in total.) and melanoma patients (f GSE93157 and Liu et al.²⁶, n = 46 in total.) following immune checkpoint inhibitor therapy. (Results are presented as mean ± SEM. Mixed-effects model followed by Tukey’s multiple comparison test or log-rank test was used to analyze the data. ns, not significant; *p < 0.05; ***p < 0.001. Source data are provided as a Source Data file.).