An atlas of epithelial cell states and plasticity in lung adenocarcinomaAbstract Understanding the cellular processes that underlie early lung adenocarcinoma (LUAD) development is needed to devise intervention strategies 1 . Here we studied 246,102 single epithelial cells from 16 early-stage LUADs and 47 matched normal lung samples. Epithelial cells comprised diverse normal and cancer cell states, and diversity among cancer cells was strongly linked to LUAD-specific oncogenic drivers. KRAS mutant cancer cells showed distinct transcriptional features, reduced differentiation and low levels of aneuploidy. Non-malignant areas surrounding human LUAD samples were enriched with alveolar intermediate cells that displayed elevated KRT8 expression (termed KRT8 + alveolar intermediate cells (KACs) here), reduced differentiation, increased plasticity and driver KRAS mutations. Expression profiles of KACs were enriched in lung precancer cells and in LUAD cells and signified poor survival. In mice exposed to tobacco carcinogen, KACs emerged before lung tumours and persisted for months after cessation of carcinogen exposure. Moreover, they acquired Kras mutations and conveyed sensitivity to targeted KRAS inhibition in KAC-enriched organoids derived from alveolar type 2 (AT2) cells. Last, lineage-labelling of AT2 cells or KRT8 + cells following carcinogen exposure showed that KACs are possible intermediates in AT2-to-tumour cell transformation. This study provides new insights into epithelial cell states at the root of LUAD development, and such states could harbour potential targets for prevention or intervention.
Inflammation Mediated by Gut Microbiome Alterations Promotes Lung Cancer Development and an Immunosuppressed Tumor MicroenvironmentZahraa Rahal, Yuejiang Liu, Fuduan Peng et al.|Cancer Immunology Research|2024 Accumulating evidence indicates that the gut microbiome influences cancer progression and therapy. We recently showed that progressive changes in gut microbial diversity and composition are closely coupled with tobacco-associated lung adenocarcinoma in a human-relevant mouse model. Furthermore, we demonstrated that the loss of the antimicrobial protein Lcn2 in these mice exacerbates protumor inflammatory phenotypes while further reducing microbial diversity. Yet, how gut microbiome alterations impinge on lung adenocarcinoma development remains poorly understood. In this study, we investigated the role of gut microbiome changes in lung adenocarcinoma development using fecal microbiota transfer and delineated a pathway by which gut microbiome alterations incurred by loss of Lcn2 fostered the proliferation of proinflammatory bacteria of the genus Alistipes, triggering gut inflammation. This inflammation propagated systemically, exerting immunosuppression within the tumor microenvironment, augmenting tumor growth through an IL6-dependent mechanism and dampening response to immunotherapy. Corroborating our preclinical findings, we found that patients with lung adenocarcinoma with a higher relative abundance of Alistipes species in the gut showed diminished response to neoadjuvant immunotherapy. These insights reveal the role of microbiome-induced inflammation in lung adenocarcinoma and present new potential targets for interception and therapy.