Avdulov, Svetlana

Abstract Rationale Chronic obstructive pulmonary disease is an independent risk factor for lung cancer, but the underlying molecular mechanisms are unknown. We hypothesized that lung stromal cells activate pathological gene expression programs that support oncogenesis. Objectives To identify molecular mechanisms operating in the lung stroma that support the development of lung cancer. Methods The study included subjects with and without lung cancer across a spectrum of lung-function values. We conducted a multiomics analysis of nonmalignant lung tissue to quantify the transcriptome, translatome, and proteome. Measurements and Main Results Cancer-associated gene expression changes predominantly manifested as alterations in the efficiency of mRNA translation modulating protein levels in the absence of corresponding changes in mRNA levels. The molecular mechanisms that drove these cancer-associated translation programs differed based on lung function. In subjects with normal to mildly impaired lung function, the mammalian target of rapamycin (mTOR) pathway served as an upstream driver, whereas in subjects with severe airflow obstruction, pathways downstream of pathological extracellular matrix emerged. Consistent with a role during cancer initiation, both the mTOR and extracellular matrix gene expression programs paralleled the activation of previously identified procancer secretomes. Furthermore, an in situ examination of lung tissue showed that stromal fibroblasts expressed cancer-associated proteins from two procancer secretomes: one that included IL-6 (in cases of mild or no airflow obstruction), and one that included BMP1 (in cases of severe airflow obstruction). Conclusions Two distinct stromal gene expression programs that promote cancer initiation are activated in patients with lung cancer depending on lung function. Our work has implications both for screening strategies and for personalized approaches to cancer treatment.

Abstract Rationale Chronic obstructive pulmonary disease (COPD) is an independent risk factor for lung cancer, but the underlying molecular mechanisms are unknown. We hypothesized that stromal cells comprising the COPD lung contain pathological gene expression programs supporting oncogenesis. Objectives To identify molecular mechanisms operating in the lung stroma that support the development of lung cancer. Methods Study subjects included patients with COPD with (n = 30) or without (n = 30) lung cancer across a spectrum of COPD severity. We conducted multi-omics analysis of nonmalignant lung tissue to quantify the transcriptome, translatome, and proteome. Results Cancer-associated gene expression changes predominantly manifested as alterations in the efficiency of mRNA translation impacting protein levels in the absence of corresponding changes in mRNA levels. The molecular mechanisms driving these procancer translation programs differed on the basis of COPD severity. In mild or no COPD, the mammalian target of rapamycin pathway served as an upstream driver; whereas in advanced COPD, pathways downstream of pathological extracellular matrix emerged. Both the mammalian target of rapamycin and extracellular matrix gene expression programs paralleled activation of previously identified secretomes that can be independently induced and promote cancer initiation in mouse models. These included the senescence secretome in mild to no COPD and the ETS2 (erythroblast transformation-specific 2) secretome in moderate to severe COPD. Furthermore, in situ examination of COPD lung tissue documented stromal fibroblasts expressing key cancer-associated proteins from procancer secretomes including IL-6 (senescence secretome) in mild COPD and bone morphogenetic protein-1 (ETS2 secretome) in advanced COPD. Conclusions Two distinct stromal gene expression programs promoting cancer initiation are activated in patients with lung cancer depending on the severity of COPD as measured by lung function. Our work has implications both for screening strategies and personalized approaches to prevent cancer in COPD.