WWOX-mediated apoptosis in A549 cells mainly involves the mitochondrial pathway.

The human WWOX gene, known as WW domain-containing oxidoreductase, is located on 16q23.3-24.1, a chromosome region that spans the common fragile site, FRA16D. Abnormal transcripts or even loss of expression are frequently found in a number of cancer cell types, including breast, ovarian, prostate and lung cancer cells. It has therefore been proposed that the WWOX gene encodes a candidate tumor suppressor, possibly a pro-apoptotic protein. However, the mechanism behind this is not entirely clear. In the present study, we examined the pro-apoptotic action of WWOX using transient expression in A549 cells. We observed that the ectopic expression of WWOX caused apoptosis in A549 cells. We further observed procaspase-3 and procaspase-9 activation and the release of cytochrome C from the mitochondria in A549 cells transfected with pcDNA3.0-WWOX. These data indicate that WWOX induces apoptosis in A549 cells via the mitochondrial pathway.