Chinese never smokers with adenocarcinoma of the lung are younger and have fewer lymph node metastases than smokers.

BACKGROUND: Lung cancers arising in never smokers have been suggested to be substantially different from lung cancers in smokers at an epidemiological, genetic and molecular level. Focusing on non-small cell lung cancer (NSCLC), we characterized lung cancer patients in China looking for demographic and clinical differences between the smoking and never-smoking subgroups. METHODS: In total, 891 patients with NSCLC, including 841 with adenocarcinoma and 50 with squamous cell carcinoma, were recruited in this study. Association of smoking status with demographic and clinical features of NSCLC was determined, and risk factors for lymph node metastasis and TNM stage were evaluated using Multivariate logistic regression analysis. RESULTS: In patients with adenocarcinoma, never smokers showed a younger age at diagnosis (54.2 ± 12.7vs. 59.3 ± 9.4, padjusted<0.001), a lower risk for lymph node metastasis than smokers (7,6% vs. 19.5%, padjusted<0.001) and less severe disease as indicated by lower percentages of patients with TNM stage of III or IV (5.5% vs. 14.7%, padjusted<0.001 ). By contrast, these associations were not observed in 50 patients with squamous cell carcinoma. Multivariate logistic regression analysis showed that smoking status was a risk factor for lymph node metastasis (OR = 2.70, 95% CI: 1.39-5.31, p = 0.004) but not for TNM stage (OR = 1.18, 95% CI: 0.09-14.43, p = 0.896) in adenocarcinoma. CONCLUSION: This study demonstrates that lung adenocarcinoma in never smokers significantly differ from those in smokers regarding both age at diagnosis and risk of lymph node metastasis, supporting the notion that they are distinct entries with different etiology and pathogenesis.

An NF-κB/OVOL2 circuit regulates glucose import and cell survival in non-small cell lung cancer.

BACKGROUND: Tumor cells tend to utilize glycolysis rather than aerobic respiration even under aerobic conditions. OVOL2, an inhibitory C2H2 zinc finger transcription factor, is a potential tumor suppressor in cancers. However, the association between OVOL2 and tumor energy metabolism is unknown. METHODS: Western blotting was used to determine the expression of OVOL2 in different non-small cell lung cancer (NSCLC) cell lines and mouse models. The metabolic parameters in NSCLC cells following overexpression or knockdown OVOL2 were examined. To define the mechanism by which OVOL2 regulates aerobic glycolysis, interacting protein of OVOl2 and downstream molecular events were identified by luciferase assay and co-immunoprecipitation. We documented the regulatory mechanism in mouse xenograft models. Finally, clinical relevance of OVOL2, NF-κB signaling and GLUT1 was measured by immunostaining. RESULTS: OVOL2 is downregulated in NSCLC and overexpression of OVOL2 inhibits the survival of cancer cells. Moreover, OVOL2 directly binds to P65 and inhibits the recruitment of P300 but facilitates the binding of HDAC1 to P65, which in turn negatively regulates NF-κB signaling to suppress GLUT1 translocation and glucose import. In contrast, OVOL2 expression is negatively regulated by NF-κB signaling in NSCLC cells via the ubiquitin-proteasome pathway. Re-expression of OVOL2 significantly compromise NF-κB signaling-induced GLUT1 translocation, aerobic glycolysis in NSCLC cells and mouse models. Immunostaining revealed inverse correlations between the OVOL2 and phosphorylated P65 levels and between the OVOL2 and membrane GLUT1 levels, and a strong correlation between the phosphorylated P65 and membrane GLUT1 levels. CONCLUSIONS: These results suggest a regulatory circuit linking NF-κB and OVOL2, which highlights the role of NF-κB signaling and OVOL2 in the modulation of glucose metabolism in NSCLC. Video Abstract.