Indole‐3‐carbinol inhibits MDA‐MB‐231 breast cancer cell motility and induces stress fibers and focal adhesion formation by activation of Rho kinase activity

Abstract

Indole-3-carbinol (I3C), a phytochemical derived from cruciferous vegetables such as broccoli and Brussels sprouts, has potent anti-proliferative effects in human breast cancer cells and has been shown to decrease metastatic spread of tumors in experimental animals. Using chemotaxis and fluorescent-bead cell motility assays, we demonstrated that I3C significantly decreased the in vitro migration of MDA-MB-231 cells, a highly invasive breast cancer cell line. Immunofluorescence staining of the actin cytoskeleton revealed that concurrent with the loss of cell motility, I3C treatment significantly increased stress fiber formation. Furthermore, I3C induced the localization of the focal adhesion component vinculin and tyrosine-phosphorylated proteins to the cell periphery, which implicates an indole-dependent enhancement of focal adhesions within the outer boundary of the cells. Co-immunoprecipitation analysis of focal adhesion kinase demonstrated that I3C stimulated the dynamic formation of the focal adhesion protein complex without altering the total level of individual focal adhesion proteins. The RhoA-Rho kinase pathway is involved in stress fiber and focal adhesion formation, and I3C treatment stimulated Rho kinase enzymatic activity, and cofilin phosphorylation, which is a downstream target of Rho kinase signaling, but did not increase the level of active GTP-bound RhoA. Exposure of MDA-MB-231 cells to the Rho kinase inhibitor Y-27632, or expression of dominant negative RhoA ablated the I3C induced formation of stress fibers and of peripheral focal adhesions. Expression of constitutively active RhoA mimicked the I3C effects on both processes. Taken together, our data demonstrate that I3C induces stress fibers and peripheral focal adhesions in a Rho kinase-dependent manner that leads to an inhibition of motility in human breast cancer cells.

Variation of glucosinolates in vegetable crops of Brassica rapa L. ssp. pekinensis

“…The breakdown products from indolic glucosinolates have been identified as phytoalexins in various Brassica species, suggesting that they have a role in plant defence (Pedras et al, 2003(Pedras et al, , 2006. Furthermore, indole-3-carbinol is a potential chemopreventive agent (Brew et al, 2009;Tolonen et al, 2002) and thus Chinese cabbage could be a good candidate for future breeding programmes.…”

“…Moreover, indole-3-carbinol, the hydrolysis product derived from glucobrassicin, is thought to modulate biotransformation enzyme activity and act as an anticarcinogen (Brew et al, 2009). However, the negative aspects of these compounds have been a major focus of research due to their ''antinutritional" or goitrogenic properties.…”

Role of Rho-Kinase Gene Polymorphisms and Protein Expressions in Colorectal Cancer Development

“…A recent study showed that the activation of Rho-kinase leads to an inhibition of motility in human breast cancer cells [27]. The active vitamin D metabolite 1,25-dihydroxyvitamin D3, used as an anticancer agent, inhibits the proliferation and promotes the differentiation to a normal adhesive epithelial phenotype of human colon cancer cells via augmentation of cytosolic Ca 2+ concentration and activation of RhoA/Rho-kinase [28].…”

The fusion of genomes leads to more options: A comparative investigation on the desulfo-glucosinolate sulfotransferases of Brassica napus and homologous proteins of Arabidopsis thaliana

“…Overexpression of SOT17 and SOT18, for example, could lead to more nitriles and epithionitriles, due to hydrolysis of the respective Gls and thereby contribute to a better plant defense. An overexpression of SOT16 could lead to a higher indolic Gl concentration, which hydrolysis products are assumed to have anti-carcinogenic properties (Brew et al, 2009). The relatively high number of SOT16s in B. rapa could lead to the assumption of a higher indolic Gl concentration, but it was shown that in general B. oleracea have the highest indolic Gl content (B. rapa: 1.58 mmol g À1 DW, B. oleracea: 7.99 mmol g À1 DW).…”