Baicalein disturbs the morphological plasticity and motility of breast adenocarcinoma cells depending on the tumor microenvironment

Abstract

During tumor invasion, cancer cells change their morphology and mode of migration based on communication with the surrounding environment. Numerous studies have indicated that paracrine interactions from non-neoplastic cells impact the migratory and invasive properties of cancer cells. Thus, these interactions are potential targets for anticancer therapies. In this study, we showed that the flavones member baicalein suppresses the motility of breast cancer cells that is promoted by paracrine interactions. First, we identified laminin-332 (LN-332) as a principle paracrine factor in conditioned medium from mammary epithelium-derived MCF10A cells that regulates the morphology and motility of breast adenocarcinoma MDA-MB-231 cells. Then, we carried out a morphology-based screen for small compounds, which showed that baicalein suppressed the morphological changes and migratory activity of MDA-MB-231 cells that were induced by conditioned medium from MCF10A cells and LN-332. We also found that baicalein caused narrower and incomplete lamellipodia formation in conditioned medium-treated MDA-MB-231 cells, although actin dynamics downstream of Rho family small GTPases were unaffected. These results suggest the importance of mammary epithelial cells in the cancer microenvironment promoting the migratory activity of breast adenocarcinoma cells and show a novel mechanism through which baicalein inhibits cancer cell motility.

Timosaponin Aiii Disrupts Morphological Plasticity and Migration of Breast Adenocarcinoma Through Inhibition of Integrin Internalisation

“…We found that TAIII suppressed morphological plasticity and migration of breast adenocarcinoma cells induced by conditioned medium from mammary epithelial cells. The activity of conditioned medium from mammary epithelial cells is mainly mediated by secreted laminin-332 [26]. Laminins are a component in the basement membrane of mammary ducts and secreted from myoepithelial cells [7].…”

“…The spatiotemporal regulation of cell surface integrins through tra cking systems gives impact to their functions in the context of cell migration [46][47][48][49][50]. Furthermore, a ligand of integrin heterodimers, laminin-332, plays important roles in the regulation of morphological plasticity and cell migration of MDA-MB-231 cells [26]. Collectively, our results lead us to propose that the activity of TAIII to block internalisation of integrin b1 should contribute, in part, to its inhibitory effect on cell migration through negative regulation of lamellipodia formation.…”

“…MCF10A cells (ATCC) were cultured in DMEM/F-12 (Thermo Fisher Scienti c) supplemented with 5% heat-inactivated horse serum (Thermo Fisher Scienti c), 20 ng/mL EGF (Miltenyi Biotec, Bergisch Gladbach, Germany), 10 mg/mL insulin (Sigma-Aldrich, St. Louis, MO, USA), 0.5 mg/mL hydrocortisone (Sigma-Aldrich), and 100 ng/mL cholera toxin (Sigma-Aldrich) at 37°C with 5% CO 2 . Preparation and treatment with conditioned medium from MCF10A cells were performed as described previously [26].…”

“…For transfection, Lipofectamine LTX (Thermo Fisher Scienti c) was used in accordance with the manufacturer's instructions. Expression plasmids for constitutively active Val12 Rac1, Val12 CDC42, and Val14 RhoA have been described previously [26]. The expression plasmid for LifeAct-mCherry was kindly provided by Dr. Naoki Watanabe (Kyoto University) and has been described previously [27].…”

“…Cell migration assays were performed in Boyden chambers as described previously [26] with minor modi cations. MDA-MB-231 cells were trypsinised, washed twice with OPTI-MEM, and then seeded at 5×10 4 cells per well in OPTI-MEM.…”