Role of Nuclear Factor-kappa B Signaling in Anticancer Properties of Indole Compounds

Indole compounds, obtained from cruciferous vegetables, are known to possess potent anticancer properties. Studies with indole-3-carbinol (I3C) and its dimeric product, 3,3’ diindolylmethane (DIM), have indicated the efficacy of these compounds against a number of human cancers, which is related to their ability to interfere with and modulate multiple cellular signaling pathways. The nuclear factor-kappa B (NF-κB) pathway plays an important role in the control of cell proliferation, metastasis, angiogenesis, and drug resistance. Emerging evidence points to an effective inhibition of NF-κB signaling by I3C and DIM. This seems to be central to most of the observed anticancer properties of these compounds. Here, we summarize our current understanding of regulation of NF-κB signaling by I3C and DIM and the resulting biological effects. Breast, prostate, and pancreatic cancers are relatively better characterized in terms of modulation of NF-κB signaling by indoles, and it is our intent that this review incites similar studies in other human cancer models as well.