The alternative NF-kB2/RELB pathway is activated by LTβ/LTβR and NIK to promote cell migration and metastasis related gene expression in HNSCC

Authors

• Rita Das
• Tsu-F Cheng
• Jamie Coupar
• Antho Anthony Saleh
• Paul Clavijo
• Xinpi Xinping Yang
• Zhong Chen
• Carte Carter VanWaes

Abstract

Head and neck squamous cell carcinomas (HNSCC) are highly inflammatory and preferentially migrate and metastasize to lymph nodes. In this study, we find that LTβ/LTβR/NIK signaling mediates alternative RELB/NF-kB2 activation, which promotes activation of important cancer related genes and migration. We find that LTβ and LTβR are overexpressed in subsets of HNSCC tissues and cell lines, and LTβ activates the alternative NF-κB pathway, enhancing nuclear translocation of RELB and NF-kB2/p52. Knockdown of LTβR decreased its target kinase NIK, and downstream NF-KB subunits RELB and NF-KB2/p52 protein expression. Knockdown of NIK protein decreased RELB and p52 protein expression, while LTβ treatment stabilized NIK, RELB and NF-kB2/p52 expression. Consistent with this, knockdown of LTBR and NIK functionally decreased NF-kB reporter gene activity, while treatment of LTB partially restored the NF-kB reporter activity. Notably, knockdown of NIK and RELB by siRNA inhibited cell migration in HNSCC. Since NIK activates the non-canonical pathway, we tested the effects of a NIK inhibitor 1,3[2H,4H]-Isoquinolinedione on NF-kB function and cell migration. NIK inhibitor decreased NIK protein in the cytoplasm, downstream nuclear expression of RELB and NF-kB2/p52 proteins by Western blot and RELB localization by immunofluorescence staining. We have found evidence for LTβ induction of migration/metastasis and cell death genes MET, BIRC3, and SERPINE1, and NIK knockdown inhibited cell migration and the inducible expression of MET, BIRC3, SERPINE 1 by LTB. Our data reveal the mechanisms how LTβ and NIK activation mediated alternative NF-kB pathway and contribute to migration and metastasis of HNSCC.

Scientific Focus Area: Cancer Biology

This page was last updated on Friday, March 26, 2021