Fig. 3: ICAM1 is important for the homing and activation of tumor-specific T cells in LKB1 deficient lung cancer.

a LLC1-OVA tumor cells (LLC1-control-Icam1^WT-OVA; LLC1-shLkb1-Icam1^WT-OVA; LLC1-shLkb1-Icam1^OE-OVA) were implanted. Congenitally-marked (APC⁺) and stimulated CD8⁺ T cells expressing the OT-I were transferred on day 7 and analyzed on day 12. b Infiltration of OT-I CD8⁺ T cells (left) and expression of CD69 on OT-I cells (right) were analyzed by flow cytometry. For CD8⁺ T cells, n = 12, n = 12 and n = 13 in control-Icam1^WT, shLkb1-Icam1^WT and shLkb1-Icam1^OE groups, respectively. ****p < 0.0001, ****p < 0.0001. For CD69, n = 12, n = 11 and n = 12 in control-Icam1^WT, shLkb1-Icam1^WT and shLkb1-Icam1^OE groups, respectively. ***p = 0.0003. c Flow cytometry analysis of CD69 and PD-1 expression on activated T cells with or without co-culturing with LLC1 tumor cells (shLkb1-Icam1^WT, shLkb1-Icam1^OE) for 24 h. The E:T ratio (effector to target) was 1:1, 5:1, and 10:1 respectively. n = 3 biologically independent samples examined over 1 independent experiment. CD69, *p = 0.038, **p = 0.0012, ***p = 0.0009; PD-1, **p = 0.0036, ***p = 0.0007, ***p = 0.0009. d Flow cytometry analysis of CD69 expression on activated T cells co-culturing with LLC1 tumor cells (control-Icam1^WT, n = 9; shLkb1-Icam1^WT, n = 9; control-Icam1^OE, n = 6; shLkb1-Icam1^OE, n = 9) for 24 h. The E:T ratio (effector to target) was 10:1. ****p < 0.0001, ****p < 0.0001. e Flow cytometry analysis of CD69 and CD44 expression on activated T cells with co-culturing of LLC1 tumor cells (LLC1-shLkb1-Icam1^OE), with or without LFA-1 antibody blockade therapy for 24 h. The E:T ratio (effector to target) was 10:1. n = 6 biologically independent samples examined over 1 independent experiment. ****p < 0.0001, ***p = 0.0006. f Correlation analysis of ICAM1 expression and cytolytic activity (CYT) patient samples (TCGA) with or without LKB1 mutations. LKB1 wild-type, n = 374 samples, p < 0.0001; LKB1 mutation, n = 68 samples, p = 0.257. g Correlation analysis of IHC staining with anti-CD8a and anti-ICAM1 antibodies on a tissue microarray (TMA) of lung adenocarcinoma patients (n = 152 TMA elements). p < 0.0001. h IHC of ICAM1 and CD8 expression in LKB1-WT and LKB1-mutant lung cancer patients. Scale bar, 20 μm (40×), 50 μm (20×). n = 11 (LKB1-WT) or n = 7 (LKB1-mutant) biologically independent samples examined over 1 independent experiment. (Results were presented as mean ± SEM. One-way ANOVA followed by Tukey’s multiple comparisons test or two-tailed Student’s t-test was used to analyze the data. ns, not significant; *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001. Source data are provided as a Source Data file.).