TWIST1 associates with NF-κB subunit RELA via carboxyl-terminal WR domain to promote cell autonomous invasion through IL8 production.
BACKGROUND
Metastasis is the primary cause of death for cancer patients. TWIST1, an evolutionarily conserved basic helix-loop-helix (bHLH) transcription factor, is a strong promoter of metastatic spread and its expression is elevated in many advanced human carcinomas. However, the molecular events triggered by TWIST1 to motivate dissemination of cancer cells are largely unknown.


RESULTS
Here we show that TWIST1 induces the production of interleukin 8 (IL8), which activates matrix metalloproteinases and promotes invasion of breast epithelial and cancer cells. In this novel mechanism, TWIST1-mediated IL8 transcription is induced through the TWIST1 carboxy-terminal WR (Trp-Arg) domain instead of the classic DNA binding bHLH domain. Co-immunoprecipitation analyses revealed that the WR domain mediates the formation of a protein complex comprised of TWIST1 and the nuclear factor-kappaB (NF-κB) subunit RELA (p65/NF-κB3), which synergistically activates the transcriptional activity of NF-κB. This activation leads to increased DNA binding affinity of RELA to the IL8 promoter and thus induces the expression of the cytokine. Blockage of IL8 signaling by IL8 neutralizing antibodies or receptor inhibition reduced the invasiveness of both breast epithelial and cancer cells, indicating that TWIST1 induces autonomous cell invasion by establishing an IL8 antocrine loop.


CONCLUSIONS
Our data demonstrate that the TWIST1 WR domain plays a critical role in TWIST1-induced IL8 expression through interactions with and activation of NF-κB. The produced IL8 signals through an autocrine loop and promotes extracellular matrix degradation to enable cell invasion across the basement membrane.
Division of Neurosciences, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
Shan
S
Li
Stephen E
SE
Kendall
Raquel
R
Raices
James
J
Finlay
Maricela
M
Covarrubias
Zheng
Z
Liu
Gina
G
Lowe
Yu-Huey
YH
Lin
Yuan Han
YH
Teh
Victoria
V
Leigh
Simi
S
Dhillon
Steven
S
Flanagan
Karen S
KS
Aboody
Carlotta A
CA
Glackin
D001943:Breast Neoplasms / Q000378:metabolism; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism*; D016328:NF-kappa B / Q000737:chemistry / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D051996:Transcription Factor RelA / Q000235:genetics / Q000378:metabolism*; D051879:Twist-Related Protein 1 / Q000235:genetics / Q000378:metabolism*
C508606:CXCL8 protein, human; D016209:Interleukin-8; D016328:NF-kappa B; D009687:Nuclear Proteins; C498143:RELA protein, human; C103173:TWIST1 protein, human; D051996:Transcription Factor RelA; D051879:Twist-Related Protein 1