Use of bioluminescent imaging to investigate the role of nuclear factor-κB in experimental non-small cell lung cancer metastasis

Nuclear factor (NF)-κB is frequently over-expressed in non-small cell lung cancer (NSCLC), but the exact role of this observation remains unclear. In this regard, activation of the transcription factor may govern distinct steps of NSCLC progression, such as carcinogenesis, angiogenesis, and metastasis. In these studies we attempted to dissect the effects of two proteins of the NF-κB pathway (p65/RelA and IκBα) on experimental metastasis of murine NSCLC, using a novel approach of bioluminescent detection of NF-κB activation in tumor cells. Stable integration of a NF-κB reporter confirmed high basal activation of the transcription factor in mouse NSCLC cells in vitro and during experimental metastasis to the lungs, like human NSCLC. In the mouse model of NSCLC metastasis, NF-κB-dependent luciferase expression served as a reliable indicator of tumor cell delivery to the lungs, establishment of metastatic tumors, and lung tumor burden. In vitro transient p65/RelA and IκBα gene transfer to mouse NSCLC cells resulted, respectively, in significant NF-κB activation and inhibition, without affecting cell growth. However, p65/RelA overexpression in NSCLC cells drastically reduced in vivo metastasis to the lungs, while overexpression of IκBα had no effect. In conclusion, using bioluminescent detection of NF-κB activation in mouse lug adenocarcinoma cells, we found a negative impact of p65/RelA on NSCLC metastasis.