Haniel A. Araújo

AIMS: Superficial erosion of atheromata causes many acute coronary syndromes, but arises from unknown mechanisms. This study tested the hypothesis that Toll-like receptor-2 (TLR2) activation contributes to endothelial apoptosis and denudation and thus contributes to the pathogenesis of superficial erosion. METHODS AND RESULTS: Toll-like receptor-2 and neutrophils localized at sites of superficially eroded human plaques. In vitro, TLR2 ligands (including hyaluronan, a matrix macromolecule abundant in eroded lesions) induced endothelial stress, characterized by reactive oxygen species production, endoplasmic reticulum (ER) stress, and apoptosis. Co-incubation of neutrophils with endothelial cells (ECs) potentiated these effects and induced EC apoptosis and detachment. We then categorized human atherosclerotic plaques (n = 56) based on morphologic features associated with superficial erosion, 'stable' fibrotic, or 'vulnerable' lesions. Morphometric analyses of the human atheromata localized neutrophils and neutrophil extracellular traps (NETs) near clusters of apoptotic ECs in smooth muscle cell (SMC)-rich plaques. The number of luminal apoptotic ECs correlated with neutrophil accumulation, amount of NETs, and TLR2 staining in SMC-rich plaques, but not in 'vulnerable' atheromata. CONCLUSION: These in vitro observations and analyses of human plaques indicate that TLR2 stimulation followed by neutrophil participation may render smooth muscle cell-rich plaques susceptible to superficial erosion and thrombotic complications by inducing ER stress, apoptosis, and favouring detachment of EC.

Molecular modifiers of KRASG12C inhibitor (KRASG12Ci) efficacy in advanced KRASG12C-mutant NSCLC are poorly defined. In a large unbiased clinicogenomic analysis of 424 patients with non-small cell lung cancer (NSCLC), we identified and validated coalterations in KEAP1, SMARCA4, and CDKN2A as major independent determinants of inferior clinical outcomes with KRASG12Ci monotherapy. Collectively, comutations in these three tumor suppressor genes segregated patients into distinct prognostic subgroups and captured ∼50% of those with early disease progression (progression-free survival ≤3 months) with KRASG12Ci. Pathway-level integration of less prevalent coalterations in functionally related genes nominated PI3K/AKT/MTOR pathway and additional baseline RAS gene alterations, including amplifications, as candidate drivers of inferior outcomes with KRASG12Ci, and revealed a possible association between defective DNA damage response/repair and improved KRASG12Ci efficacy. Our findings propose a framework for patient stratification and clinical outcome prediction in KRASG12C-mutant NSCLC that can inform rational selection and appropriate tailoring of emerging combination therapies. SIGNIFICANCE: In this work, we identify co-occurring genomic alterations in KEAP1, SMARCA4, and CDKN2A as independent determinants of poor clinical outcomes with KRASG12Ci monotherapy in advanced NSCLC, and we propose a framework for patient stratification and treatment personalization based on the comutational status of individual tumors. See related commentary by Heng et al., p. 1513. This article is highlighted in the In This Issue feature, p. 1501.

For patients with advanced non-small-cell lung cancer (NSCLC), dual immune checkpoint blockade (ICB) with CTLA4 inhibitors and PD-1 or PD-L1 inhibitors (hereafter, PD-(L)1 inhibitors) is associated with higher rates of anti-tumour activity and immune-related toxicities, when compared with treatment with PD-(L)1 inhibitors alone. However, there are currently no validated biomarkers to identify which patients will benefit from dual ICB1,2. Here we show that patients with NSCLC who have mutations in the STK11 and/or KEAP1 tumour suppressor genes derived clinical benefit from dual ICB with the PD-L1 inhibitor durvalumab and the CTLA4 inhibitor tremelimumab, but not from durvalumab alone, when added to chemotherapy in the randomized phase III POSEIDON trial3. Unbiased genetic screens identified loss of both of these tumour suppressor genes as independent drivers of resistance to PD-(L)1 inhibition, and showed that loss of Keap1 was the strongest genomic predictor of dual ICB efficacy—a finding that was confirmed in several mouse models of Kras-driven NSCLC. In both mouse models and patients, KEAP1 and STK11 alterations were associated with an adverse tumour microenvironment, which was characterized by a preponderance of suppressive myeloid cells and the depletion of CD8+ cytotoxic T cells, but relative sparing of CD4+ effector subsets. Dual ICB potently engaged CD4+ effector cells and reprogrammed the tumour myeloid cell compartment towards inducible nitric oxide synthase (iNOS)-expressing tumoricidal phenotypes that—together with CD4+ and CD8+ T cells—contributed to anti-tumour efficacy. These data support the use of chemo-immunotherapy with dual ICB to mitigate resistance to PD-(L)1 inhibition in patients with NSCLC who have STK11 and/or KEAP1 alterations. Alterations in the tumour suppressor genes STK11 and/or KEAP1 can identify patients with advanced non-small-cell lung cancer who are likely to benefit from combinations of PD-(L)1 and CTLA4 immune checkpoint inhibitors added to chemotherapy.