Functional interrelationship between the WASF3 and KISS1 metastasis-associated genes in breast cancer cells.

Loss of WASF3 function in breast cancer cells results in loss of invasion phenotypes and reduced metastatic potential. By using oligonucleotide arrays, we now demonstrate that knockdown of WASF3 leads to the upregulation of the KISS1 metastasis suppressor gene with concomitant reduced invasion and loss of matrix metalloproteinases (MMP)-9 activity. Using a luciferase reporter, KISS1 transcription is significantly increased in the absence of WASF3. Knockdown of KISS1 in WASF3-silenced cells resulted in the recovery of the invasion phenotype. WASF3 knockdown also resulted in elevated IκBα levels in the cytoplasm and reduced levels of nuclear factor-kappa-B (NF-κB) p65/50 subunits in the nucleus. Tumor necrosis factor-alpha (TNF-α) has been associated with cell invasion through induction of MMP-9 production via KISS1 regulation of the NF-κB pathway. When WASF3 knockdown cells are treated with TNF-α, no effect is seen on invasion or nuclear translocation of NF-κB. Thus, coordinated expression patterns of the WASF3 metastasis promoter gene and the KISS1 metastasis suppressor gene appear to exert their influence through inhibition of NF-κB signaling, which in turn regulates MMP-9 production facilitating invasion.