The effect of fish oil on ILK promoter activity was blocked when the upstream portion of the ILK
gene promoter containing AP-2 sites was deleted, and in cells transfected with AP-2α siRNA
suggesting that AP-2α plays a critical role in mediating the effect of fish oil on ILK gene
expression. Furthermore, increased AP-2α expression and AP-2α DNA binding activity were
responsible for the inhibitory effect of fish oil on ILK expression. On the contrary, silencing
AP-2α blocked the inhibitory effect of fish oil on NSCLC cell proliferation further indicating
the tumor suppressive property of this transcription factor. Similarly, another study
demonstrated that targeting constitutive expression of AP-2α in colon cancer cells with siRNA
resulted in an increase in their invasive potential, downregulation of E-cadherin, and increased
expression of matrix metalloproteinase-9 (39). The AP-2 transcription factor is involved in the
regulation of cell proliferation, differentiation, apoptosis and carcinogenesis. AP-2α functions
as a tumor suppressor in several cancers (40). Overexpression of AP-2α significantly decreased
cell proliferation and invasion concomitant to the up-regulation of p27 expression in pancreatic
cancer cells (41). Also, transient expression of AP-2α resulted in the induction of PTEN
transcription in AP-2α-negative colon cancer cells (42).