Silymarin targets β-catenin signaling in blocking migration/invasion of human melanoma cells.
Vaid M1, Prasad R, Sun Q, Katiyar SK.
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1Department of Dermatology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America.
Metastatic melanoma is a leading cause of death from skin diseases, and is often associated with activation of Wnt/β-catenin signaling pathway. We have examined the inhibitory effect of silymarin, a plant flavanoid from Silybum marianum, on cell migration of metastasis-specific human melanoma cell lines (A375 and Hs294t) and assessed whether Wnt/β-catenin signaling is the target of silymarin. Using an in vitro invasion assay, we found that treatment of human melanoma cell lines with silymarin resulted in concentration-dependent inhibition of cell migration, which was associated with accumulation of cytosolic β-catenin, while reducing the nuclear accumulation of β-catenin (i.e., β-catenin inactivation) and reducing the levels of matrix metalloproteinase (MMP) -2 and MMP-9 which are the down-stream targets of β-catenin. Silymarin enhanced: (i) the levels of casein kinase 1α, glycogen synthase kinase-3β and phosphorylated-β-catenin on critical residues Ser(45), Ser(33/37) and Thr(41), and (ii) the binding of β-transducin repeat-containing proteins (β-TrCP) with phospho forms of β-catenin in melanoma cells. These events play important roles in degradation or inactivation of β-catenin. To verify whether β-catenin is a potent molecular target of silymarin, the effect of silymarin was determined on β-catenin-activated (Mel 1241) and β-catenin-inactivated (Mel 1011) melanoma cells. Treatment of Mel 1241 cells with silymarin or FH535, an inhibitor of Wnt/β-catenin pathway, significantly inhibited cell migration of Mel 1241 cells, which was associated with the elevated levels of casein kinase 1α and glycogen synthase kinase-3β, and decreased accumulation of nuclear β-catenin and inhibition of MMP-2 and MMP-9 levels. However, this effect of silymarin and FH535 was not found in Mel 1011 melanoma cells. These results indicate for the first time that silymarin inhibits melanoma cell migration by targeting β-catenin signaling pathway.
Силибинин триггеры апоптотических сигнальных путей и autophagic выживания ответ в человеческой аденокарциномы толстой кишки клеток и их производных метастатических клеток.
Kauntz Ч1, Bousserouel S, Gossé F, Рауль F.
Сведения об авторе
Реферат
Силибинин, flavonolignan изолирован от расторопши завод (Silybum marianum), обладает противоопухолевыми свойствами. In vitro и in vivo исследования недавно показали, что силибинин блокирует рост колоректального рака (CRC). Настоящее исследование посвящено изучению механизмов силибинин-индуцированной гибели клеток с использованием in vitro модели человеческой толстой кишки рак прогрессии, состоящей из первичных опухолевых клеток (SW480) и их производные метастатических клеток (SW620) изолирован от метастаз из одного и того же пациента. Силибинин индуцированной апоптотической гибели клеток свидетельствует фрагментации ДНК и активацией каспазы-3 в обеих клеточных линий. Силибинин усиленной выражение (белка и мРНК) TNF-related apoptosis-индуцирующий лиганд (TRAIL) рецепторы смерти (DR4/DR5) на поверхности клеток в клетки SW480 и индуцированной их выражение в TRAIL-резистентных SW620 клетки, как правило, не экспрессирующих DR4/DR5. Каспазы-8 и -10 уже были активированы демонстрируя привлечением внешних апоптотические пути в силибинин-лечение SW480 и SW620 клеток. Белка Bid был расщепляется в клетках SW480 с указанием кросс-беседы внешние и внутренние пути апоптоза. Мы показали, что силибинин активированный также внутренние пути апоптоза в обеих клеточных линий, включая возмущения мембранный потенциал митохондрий, высвобождение цитохрома С В цитозоль и активации каспазы-9. Одновременно апоптоза, силибинин, вызвал autophagic ответ. Ингибирование аутофагии с помощью специфического ингибитора усиленной гибели клеток, что свидетельствует о цитопротекторной функции для аутофагии в силибинин-обработанных клетках. Взятые вместе, наши данные показали, что силибинин возбуждено в SW480 и SW620 клеток в autophagic-опосредованной выживания ответ перегружены активации как внешние и внутренние апоптотических путей.
Apoptosis. 2011 Oct;16(10):1042-53. doi: 10.1007/s10495-011-0631-z.
Silibinin triggers apoptotic signaling pathways and autophagic survival response in human colon adenocarcinoma cells and their derived metastatic cells.
Kauntz H1, Bousserouel S, Gossé F, Raul F.
Author information -
1Laboratory of Nutritional Cancer Prevention, University of Strasbourg, Unistra, EA 4438, IRCAD, 1 Place de l'Hôpital, 67091, Strasbourg-Cedex, France.
Abstract
Silibinin, a flavonolignan isolated from the milk thistle plant (Silybum marianum), possesses anti-neoplastic properties. In vitro and in vivo studies have recently shown that silibinin inhibits the growth of colorectal cancer (CRC). The present study investigates the mechanisms of silibinin-induced cell death using an in vitro model of human colon cancer progression, consisting of primary tumor cells (SW480) and their derived metastatic cells (SW620) isolated from a metastasis of the same patient. Silibinin induced apoptotic cell death evidenced by DNA fragmentation and activation of caspase-3 in both cell lines. Silibinin enhanced the expression (protein and mRNA) of TNF-related apoptosis-inducing ligand (TRAIL) death receptors (DR4/DR5) at the cell surface in SW480 cells, and induced their expression in TRAIL-resistant SW620 cells normally not expressing DR4/DR5. Caspase-8 and -10 were activated demonstrating the involvement of the extrinsic apoptotic pathway in silibinin-treated SW480 and SW620 cells. The protein Bid was cleaved in SW480 cells indicating a cross-talk between extrinsic and intrinsic apoptotic pathway. We demonstrated that silibinin activated also the intrinsic apoptotic pathway in both cell lines, including the perturbation of the mitochondrial membrane potential, the release of cytochrome c into the cytosol and the activation of caspase-9. Simultaneously to apoptosis, silibinin triggered an autophagic response. The inhibition of autophagy with a specific inhibitor enhanced cell death, suggesting a cytoprotective function for autophagy in silibinin-treated cells. Taken together, our data show that silibinin initiated in SW480 and SW620 cells an autophagic-mediated survival response overwhelmed by the activation of both the extrinsic and intrinsic apoptotic pathways.
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