epidermal-growth-factor and indole-3-carbinol

We determined whether indole-3-carbinol (I3C) could affect DU145 human prostate carcinoma cell migration to prevent the development and progression of prostate cancer. Although previous studies have shown anticancer properties of I3C in various cancer cell lines, it has not been determined how I3C regulates epidermal growth factor (EGF)-induced migration and related signaling pathways. DU145 cells were treated with I3C (100 microM) in the absence or presence of EGF (10 ng/ml). Our results showed that I3C significantly inhibited DU145 cell migration with and without EGF stimulation. It has been reported that the beta-catenin signaling pathway controls androgen receptor (AR)-mediated prostate cancer progression, which plays a key role in the metastasis of prostate cancer. Western blot analysis demonstrated that I3C led to the phosphorylation of beta-catenin and subsequent degradation of beta-catenin in the absence and presence of EGF. In contrast, I3C did not have any effect on the expression of beta-catenin mRNA. From these results, we suggest that I3C inhibits EGF (dependent or independent)-induced DU145 cell migration through beta-catenin degradation.

Topics: Anticarcinogenic Agents; beta Catenin; Cell Movement; Epidermal Growth Factor; Humans; Indoles; Male; Phosphorylation; Prostatic Neoplasms

Indole-3-carbinol has been proposed to induce apoptosis via a mechanism involving inhibition of protein kinase B (PKB) signaling in breast and prostate tumor cell lines. However, no functional data exist, and the effect of indole-3-carbinol on viability is known to be highly cell type specific. Here, we examine any requirement for PKB inhibition in induction of apoptosis by indole-3-carbinol in the MDA MB468 cell line using in vitro kinase assays, transfection, Western blotting, and flow cytometry. Comparison is also made with MCF10CA1 breast and PC3 prostate tumor cells.. Indole-3-carbinol directly inhibited activity of phosphatidylinositol 3-kinase (PI3K) immunoprecipitated from HBL100 or MDA MB468 cells in vitro. Nonetheless, we present three lines of evidence that inhibition of PI3K/PKB signaling is not required for induction of apoptosis by indole-3-carbinol. First, 50% inhibition of PKB phosphorylation by LY294002 resulted in only 15% apoptosis after 72 hours, whereas similar PKB inhibition by indole-3-carbinol coincided with 30% apoptosis after only 24 hours. Second, induction of phospho-PKB (p-PKB) levels following stimulation with epidermal growth factor did not prevent indole-3-carbinol-induced apoptosis. Third, overexpression of active PKBalpha did not prevent induction of apoptosis by indole-3-carbinol. Inhibition of PKB phosphorylation by LY294002 in the PC3 and MCF10CA1 tumor cell lines similarly failed to result in a significant increase in apoptosis.. Our results show that inhibition of PI3K/PKB signaling by indole-3-carbinol or LY294002 is not directly correlated with induction of apoptosis in several breast or prostate cell lines.

Topics: Antioxidants; Apoptosis; Blotting, Western; Breast Neoplasms; Chromones; Drug Combinations; Enzyme Inhibitors; Epidermal Growth Factor; Female; Flow Cytometry; Humans; Immunoprecipitation; Indoles; Male; Morpholines; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Prostatic Neoplasms; Signal Transduction; Transfection; Tumor Cells, Cultured