Abstract
Chronic pulmonary inflammation has been consistently shown to increase the risk of lung cancer. Therefore, assessing the molecular links between the two diseases and identification of chemopreventive agents that inhibit inflammation-driven lung tumorigenesis is indispensable. Female A/J mice were treated with the tobacco smoke carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and lipopolysaccharide (LPS), a potent inflammatory agent and constituent of tobacco smoke, and maintained on control diet or diet supplemented with the chemopreventive agents indole-3-carbinol (I3C) and/or silibinin (Sil). At the end of the study, mice were sacrificed and tumors on the surface of the lung were counted and gene expression levels in lung tissues were determined by RNA sequencing. The mean number of lung tumors induced by NNK and NNK+LPS was 5 and 15 tumors/mouse, respectively. Dietary supplementation with the combination of I3C and Sil significantly reduced the size and multiplicity (by 50%) of NNK+LPS-induced lung tumors. Also, we found that 330, 2957, and 1143 genes were differentially regulated in mice treated with NNK, LPS, and NNK+LPS, respectively. The inflammatory response of lung tumors to LPS, as determined by the number of proinflammatory genes with altered gene expression or the level of alteration, was markedly less than that of normal lungs. Among 1143 genes differentially regulated in the NNK+LPS group, the expression of 162 genes and associated signaling pathways was significantly modulated by I3C and/or Sil+I3C. These genes include cytokines, chemokines, putative oncogenes and tumor suppressor genes and Ros1, AREG, EREG, Cyp1a1, Arntl, and Npas2. To our knowledge, this is the first report that provides insight into genes that are differentially expressed during inflammation-driven lung tumorigenesis and the modulation of these genes by chemopreventive agents.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.