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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. 5S647uSA4FfDHArbVFhiZ4 Video Abstract [ABSTRACT FROM AUTHOR]

Background: Chronic gastritis has been demonstrated to be a key cause of gastric cancer (GC), and control of gastric inflammation is regarded as an effective treatment for the clinical prevention of gastric carcinogenesis. However, there remains an unmet need to identify the dominant regulators of gastric oncogenesis-associated inflammation in vivo. Methods: The mouse model for the study of inflammation-associated GC was induced by Benzo[a]pyrene (BaP) intragastric administration in Bcl6b−/− and wildtype mice on a C57BL/6 background. 5-Aza-2′-deoxycytidine (5-Aza), the demethylation drug, was intraperitoneally injected to restore Bcl6b expression. Human GC tissue array was used to analyse patient survival based on BCL6B and CD3 protein expression. Results: Bcl6b was gradually downregulated by its own promoter hypermethylation in parallel to an increasing inflammatory response during the progression of BaP-induced gastric carcinogenesis in mice. Moreover, knockout of Bcl6b dramatically worsened the severity of gastric cancer and aggravated the inflammatory response in the BaP-induced mice GC model. Re-activation of Bcl6b by 5-Aza impeded inflammatory amplification and BaP-induced GC development, prolonging survival time in wildtype mice, whereas no notable curative effect occurred in Bcl6b−/− mice with 5-Aza treatment. Finally, significant negative correlations were detected between the mRNA levels of BCL6B and inflammatory cytokines in human GC tissues; patients harbouring BCL6B-negetive and severe-inflammation GC tumours were found to exhibit the shortest survival time. Conclusions: Epigenetic inactivation of Bcl6b promotes gastric cancer through amplification of the gastric inflammatory response in vivo and offers a new approach for GC treatment and regenerative medicine. [ABSTRACT FROM AUTHOR]