Silibinin inhibits prostate cancer invasion, motility and migration by suppressing vimentin and MMP-2 expression

Abstract

Aim: Silibinin is known to exert growth inhibition and cell death together with cell cycle arrest and apoptosis in human prostate cancer cells. Whether silibinin could inhibit the invasion, motility and migration of prostate cancer cells remains largely unknown. This study was designed to evaluate this efficacy and possible mechanisms using a novel highly bone metastatic ARCaP M cell model. Methods: Four prostate cancer cell lines, LNCaP, PC-3, DU145, and ARCaP M , were used in this study. These cells were treated with increasing concentrations of silibinin (50, 100, and 200 μmol/L) for different periods of time. After treatment, cell viabilities of four prostate cancer cells were compared by MTT assay. Alterations of ARCaP M cell invasion, motility and migration were assessed by cell invasion, motility and wound healing assays. The changes of vimentin expression were observed by Western blotting and immunofluorescence staining, and the expression of MMP-2, MMP-9, and uPA was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Results: ARCaP M cells showed less sensitivity to the growth inhibition of pharmacological doses of silibinin than LNCaP, PC-3, and DU145 cells. However, silibinin exerted significant dose-and time-dependent inhibitory effects on the invasion, motility and migration of ARCaP M cells. Furthermore, the expression of vimentin and MMP-2, but not MMP-9 or uPA, was down-regulated in a dose-and timedependent manner after treatment of silibinin. Conclusion: This study shows that silibinin could inhibit the invasion, motility and migration of ARCaP M cells via down-regulation of vimentin and MMP-2 and therefore may be a promising agent against prostate cancer bone metastasis.

Metabolic reprogramming of the tumor

“…The switch from cytokeratin to vimentin expression takes place at the periphery and the invasive front of the tumor (Wu et al, 2009). As in tumor growth, hypoxia induces HIF-1, as a pleiotropic master switch of the cell biological processes responsible for tumor invasion.…”

Silibinin reverses epithelial-to-mesenchymal transition in metastatic prostate cancer cells by targeting transcription factors

“…Silibinin was obtained from Sigma (St. Louis, MO, USA) and dissolved in dimethyl sulfoxide (DMSO). For silibinin treatment, stock solution (0.05 M in DMSO) was added into culture medium to achieve appropriate concentration (100 μmol/l) as described (26), and then incubated with cells for indicated time periods (24-72 h), whereas DMSO solution without silibinin was used as control. Cell morphology was examined under a light microscope and photomicrographs were taken using Olympus C5050Z digital camera (x200, magnification).…”

“…Utilizing the unique highly bone metastatic ARCaP M cell model with a spindle-shaped mesenchymal phenotype, we have previously demonstrated that silibinin could inhibit the invasion, motility and migration of prostate cancer cells in vitro (26). The ARCaP M cells are derived from ARCaP E cells which undergo EMT by exposing to soluble factors such as TGF-ß1 plus EGF, IGF-1, ß2-microglobulin or a bone microenvironment.…”

Specific survivin dual fluorescence resonance energy transfer molecular beacons for detection of human bladder cancer cells

“…Western blot analysis was performed as previously described [13] . Human BCa cell lines and HDF-a cells were washed with cold PBS twice; then, total cellular protein lysates were prepared with RIPA buffer [50 mmol/L Tris (pH 8.0), 150 mmol/L NaCl, 0.1% SDS, 1% NP40 and 0.5% sodium deoxycholate] containing proteinase inhibitors (1% protease inhibitor cocktail and 1 mmol/L phenylmethanesulfonyl fluoride, both from Sigma, St Louis, MO, USA).…”