5-Formylhonokiol exerts anti-angiogenesis activity via inactivating the ERK signaling pathway

Our previous report has demonstrated that 5-formylhonokiol (FH), a derivative of honokiol (HK), exerts more potent anti-proliferative activities than honokiol in several tumor cell lines. In present study, we first explored the antiangiogenic activities of 5-formylhonokiol on proliferation, migration and tube formation of human umbilical vein endothelial cells (HUVECs) for the first time in vitro. Then we investigated the in vivo antiangiogenic effect of 5-formylhonokiol on zebrafish angiogenesis model. In order to clarify the underlying molecular mechanism of 5-formylhonokiol, we investigated the signaling pathway involved in controlling the angiogenesis process by western blotting assay. Wound-healing results showed that 5-formylhonokiol significantly and dose-dependently inhibited migration of cultured human umbilical vein enthothelial cells. The invasiveness of HUVEC cells was also effectively suppressed at a low concentration of 5-formylhonokiol in the transwell assay. Further F-actin imaging revealed that inhibitory effect of 5-formylhonokiol on invasion may partly contribute to the disruption of assembling stress fiber. Tube formation assay, which is associated with endothelial cells migration, further confirmed the anti-angiogenesis effect of 5-formylhonokiol. In in vivo zebrafish angiogenesis model, we found that 5-formylhonokiol dose-dependently inhibited angiogenesis. Furthermore, western blotting showed that 5-formylhonokiol significantly down-regulated extracellular signal-regulated kinase (ERK) expression and inhibited the phosphorylation of ERK but not affecting the total protein kinase B (Akt) expression and related phosphorylation, suggesting that 5-formylhonokiol might exert anti-angiogenesis capacity via down-regulation of the ERK signal pathway. Taken together, these data suggested that 5-formylhonokiol might be a viable drug candidate in antiangiogenesis and anticancer therapies.     

The Inhibition of Gastric Cancer Cells’ Progression by 23,24-Dihydrocucurbitacin E through Disruption of the Ras/Raf/ERK/MMP9 Signaling Pathway

Gastric cancer is considered to be one of the most common causes of cancer death worldwide due to its high recurrence and metastasis rates. The molecule 23,24-Dihydrocucurbitacin E (DHCE) is a cucurbitacin-derived tetracyclic triterpenoid compound that has anti-tumor activity, but the exact mechanism remains to be elucidated. This research aimed to explore the effects of DHCE on human gastric cancer cells and the possible mechanisms. The results showed that DHCE suppressed proliferation, migration, and invasion of gastric cancer cells, as well as induced apoptosis and G2/M phase arrest. Mechanistically, the potential targets and pathways of DHCE were predicted using database screening and verified using a molecular docking study, fluorescence staining, and Western blot. The results indicated that DHCE obviously inhibited the kinase activity of ERK2 via targeting its ATP-binding domain, destroyed F-actin microfilament, and reduced the expression levels of Ras, p-c-Raf, ERK, p-ERK, and MMP9 proteins. Collectively, our study demonstrated that DHCE suppressed gastric cancer cells’ proliferation, migration, and invasion through targeting ERK2 and disrupting the Ras/Raf/ERK/MMP9 signaling pathway. These properties make DHCE a promising candidate drug for the further design and development of novel and effective Ras/Raf/ERK/MMP9 pathway inhibitors for treating gastric cancer.     

Triptolide inhibits ovarian cancer cell invasion by repression of matrix metalloproteinase 7 and 19 and upregulation of E-cadherin

Triptolide, a compound extracted from the traditional Chinese medicine preparation of Tripterygium wilfordii Hook F., has been reported to have anti-inflammatory and anti-cancer activities. However, its effect on ovarian cancer invasion is unknown. We observed that MMP7 and MMP19 expression increased in ovarian cancer tissue. Triptolide treatment inhibited the migration and invasion of ovarian cancer cells SKOV3 and A2780 at the concentration of 15 nM. We also observed that triptolide suppressed MMP7 and MMP19 promoter activity in a dose-dependent manner, down-regulating the expressions of these promoters on mRNA and protein level. Moreover, triptolide enhanced E-cadherin expression in ovarian cancer cells. In vivo, triptolide inhibited tumor formation and metastasis in nude mice, and suppressed MMP7 and MMP19 expression; it also enhanced E-cadherin expression in tumor in a dose-dependent manner. Over expression of MMP7 and MMP19, or suppression of E-cadherin expression partially abolished the inhibitory effect of triptolide on invasion of ovarian cancer cells. To summarize, triptolide significantly inhibited the migration and invasion of ovarian cancer cells by suppression of MMP7 and MMP19 and up-regulation of E-cadherin expression. This study shows that triptolide is a good candidate for the treatment of ovarian cancer and reduction of metastasis.     

Regulation of hepatocyte growth factor-mediated urokinase plasminogen activator secretion by MEK/ERK activation in human stomach cancer cell lines

The regulatory mechanisms for the proliferation and the particular invasive phenotypes of stomach cancers are not still fully understood. Up-regulations of hepatocytes growth factor (HGF), its receptor (c-Met), and urokinase-type plasminogen activator (uPA) are correlated with the development and metastasis of cancers. In order to investigate roles of HGF/c-Met signaling in tumor progression and metastasis in stomach cancers, we determined effects of a specific MEK1 inhibitor (PD098059) and a p38 kinase inhibitor (SB203580) on HGF-mediated cell proliferation and uPA expression in stomach cancer cell lines (NUGC-3 and MKN-28). HGF treatment induced the phosphorylations of ERK and p38 kinase in time- and dose- dependent manners. Pre-treatment with PD098059 reduced HGF-mediated cell proliferation and uPA secretion. In contrast, SB203580 pre-treatment enhanced cell proliferation and uPA secretion due to induction of ERK phosphorylation. Stable expression of dominant negative-MEK1 in NUGC-3 cells showed a decrease in HGF-mediated uPA secretion. These results suggest that interaction of a MEK/ERK and a p38 kinase might play an important role in proliferation and invasiveness of stomach cancer cells.     

Role of mTOR signaling in tumor cell motility, invasion and metastasis

Tumor cell migration and invasion play fundamental roles in cancer metastasis. The mammalian target of rapamycin (mTOR), a highly conserved and ubiquitously expressed serine/threonine (Ser/Thr) kinase, is a central regulator of cell growth, proliferation, differentiation and survival. Recent studies have shown that mTOR also plays a critical role in the regulation of tumor cell motility, invasion and cancer metastasis. Current knowledge indicates that mTOR functions as two distinct complexes, mTORC1 and mTORC2. mTORC1 phosphorylates p70 S6 kinase (S6K1) and eukaryotic initiation factor 4E (eIF4E) binding protein 1 (4E-BP1), and regulates cell growth, proliferation, survival and motility. mTORC2 phosphorylates Akt, protein kinase C α (PKCα) and the focal adhesion proteins, and controls the activities of the small GTPases (RhoA, Cdc42 and Rac1), and regulates cell survival and the actin cytoskeleton. Here we briefly review recent knowledge of mTOR complexes and the role of mTOR signaling in tumor cell migration and invasion. We also discuss recent efforts about the mechanism by which rapamycin, a specific inhibitor of mTOR, inhibits cell migration, invasion and cancer metastasis.     

Synergistic induction of cancer cell migration regulated by Gβγ and phosphatidylinositol 3-kinase

Phosphatidylinositol 3-kinase (PI3K) is essential for both G protein-coupled receptor (GPCR)- and receptor tyrosine kinase (RTK)-mediated cancer cell migration. Here, we have shown that maximum migration is achieved by full activation of phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger 1 (P-Rex1) in the presence of Gβγ and PI3K signaling pathways. Lysophosphatidic acid (LPA)- induced migration was higher than that of epidermal growth factor (EGF)-induced migration; however, LPA-induced activation of Akt was lower than that stimulated by EGF. LPA-induced migration was partially blocked by either Gβγ or RTK inhibitor and completely blocked by both inhibitors. LPA-induced migration was synergistically increased in the presence of EGF and vice versa. In correlation with these results, sphingosine-1-phosphate (S1P)-induced migration was also synergistically induced in the presence of insulin-like growth factor-1 (IGF-1). Finally, silencing of P-Rex1 abolished the synergism in migration as well as in Rac activation. Moreover, synergistic activation of MMP-2 and cancer cell invasion was attenuated by silencing of P-Rex1. Given these results, we suggest that P-Rex1 requires both Gβγ and PI3K signaling pathways for synergistic activation of Rac, thereby inducing maximum cancer cell migration and invasion.     

Cannabis-Derived Compounds Cannabichromene and Δ9-Tetrahydrocannabinol Interact and Exhibit Cytotoxic Activity against Urothelial Cell Carcinoma Correlated with Inhibition of Cell Migration and Cytoskeleton Organization

Cannabis sativa contains more than 500 constituents, yet the anticancer properties of the vast majority of cannabis compounds remains unknown. We aimed to identify cannabis compounds and their combinations presenting cytotoxicity against bladder urothelial carcinoma (UC), the most common urinary system cancer. An XTT assay was used to determine cytotoxic activity of C. sativa extracts on T24 and HBT-9 cell lines. Extract chemical content was identified by high-performance liquid chromatography (HPLC). Fluorescence-activated cell sorting (FACS) was used to determine apoptosis and cell cycle, using stained F-actin and nuclei. Scratch and transwell assays were used to determine cell migration and invasion, respectively. Gene expression was determined by quantitative Polymerase chain reaction (PCR). The most active decarboxylated extract fraction (F7) of high-cannabidiol (CBD) C. sativa was found to contain cannabichromene (CBC) and Δ9-tetrahydrocannabinol (THC). Synergistic interaction was demonstrated between CBC + THC whereas cannabinoid receptor (CB) type 1 and type 2 inverse agonists reduced cytotoxic activity. Treatments with CBC + THC or CBD led to cell cycle arrest and cell apoptosis. CBC + THC or CBD treatments inhibited cell migration and affected F-actin integrity. Identification of active plant ingredients (API) from cannabis that induce apoptosis and affect cell migration in UC cell lines forms a basis for pre-clinical trials for UC treatment.     

Cyclooxygenase-2 promotes cell proliferation, migration and invasion in U2OS human osteosarcoma cells

Osteosarcoma is the most common primary bone tumor, but the pathogenesis is not well understood. While cyclooxygeanse-2 (COX-2) is known to be closely associated with tumor growth and metastasis in several kinds of human tumors, the function of COX-2 in osteosarcoma is unclear. Therefore, to investigate the function of COX-2 in osteosarcoma, we established stable cell lines overexpressing COX-2 in U2OS human osteosarcoma cells. COX-2 overexpression as well as prostaglandin E2 treatment promoted proliferation of U2OS cells. In addition, COX-2 overexpression enhanced mobility and invasiveness of U2OS cells, which was accompanied by increases of matrix metalloproteinase-2 and -9 (MMP-2 and -9) activities. Selective COX-2 inhibitors, NS-398 and celecoxib, inhibited cell proliferation and abrogated the enhanced mobility, invasiveness and MMP activities induced by COX-2 overexpression. These results suggest that COX-2 is directly associated with cell proliferation, migration and invasion in human osteosarcoma cells, and the therapeutic value of COX-2 inhibitors should be evaluated continuously.     

Studying the Binding Modes of Novel 2-Aminopyridine Derivatives as Effective and Selective c-Met Kinase Type 1 Inhibitors Using Molecular Modeling Approaches

The mesenchymal epithelial cell transforming factor c-Met, encoded by c-Met proto-oncogene and known as a high-affinity receptor for Hepatocyte Growth Factor (HGF), is one of the receptor tyrosine kinases (RTKs) members. The HGF/c-Met signaling pathway has close correlation with tumor growth, invasion and metastasis. Thus, c-Met kinase has emerged as a prominent therapeutic target for cancer drug discovery. Recently a series of novel 2-aminopyridine derivatives targeting c-Met kinase with high biological activity were reported. In this study, 3D quantitative structure-activity relationship (QSAR), molecular docking and molecular dynamics simulations (MD) were employed to research the binding modes of these inhibitors.The results show that both the atom-based and docking-based CoMFA (Q² = 0.596, R² = 0.950 in atom-based model and Q² = 0.563, R² = 0.985 in docking-based model) and CoMSIA (Q² = 0.646, R² = 0.931 in atom-based model and Q² = 0.568, R² = 0.983 in docking-based model) models own satisfactory performance with good reliabilities and powerful external predictabilities. Molecular docking study suggests that Tyr1230 and Arg1208 might be the key residues, and electrostatic and hydrogen bond interactions were shown to be vital to the activity, concordance with QSAR analysis. Then MD simulation was performed to further explore the binding mode of the most potent inhibitor. The obtained results provide important references for further rational design of c-Met Kinase type I inhibitors.     

Epigallocatechin-3-gallate inhibits paracrine and autocrine hepatocyte growth factor/scatter factor-induced tumor cell migration and invasion

Aberrant activation of hepatocyte growth factor/scatter factor (HGF/SF) and its receptor, Met, is involved in the development and progression of many human cancers. In the cell-based screening assay, (-)epigallocatechin-3-gallate (EGCG) inhibited HGF/SF-Met signaling as indicated by its inhibitory activity on HGF/SF-induced cell scattering and uPA activation (IC50=15.8 microgram/ml). Further analysis revealed that EGCG at low doses specifically inhibited HGF/SF-induced tyrosine phosphorylation of Met but not epidermal growth factor (EGF)-induced phosphorylation of EGF receptor (EGFR). On the other hand, high-dose EGCG decreased both Met and EGFR proteins. We also found that EGCG did not act on the intracellular portion of Met receptor tyrosine kinase, i.e., it inhibited InlB-dependent activation of Met but not NGF-induced activation of Trk-Met hybrid receptor. This inhibition decreased HGF-induced migration and invasion by parental or HGF/SF-transfected B16F10 melanoma cells in vitro in either a paracrine or autocrine manner. Furthermore, EGCG inhibited the invasion/metastasis of HGF/SF-transfected B16F10 melanoma cells in mice. Our data suggest the possible use of EGCG in human cancers associated with dysregulated paracrine or autocrine HGF/SF-Met signaling.     

β-Carotene Inhibits Expression of Matrix Metalloproteinase-10 and Invasion in Helicobacter pylori-Infected Gastric Epithelial Cells

Matrix metalloproteinases (MMPs), key molecules of cancer invasion and metastasis, degrade the extracellular matrix and cell–cell adhesion molecules. MMP-10 plays a crucial role in Helicobacter pylori-induced cell-invasion. The mitogen-activated protein kinase (MAPK) signaling pathway, which activates activator protein-1 (AP-1), is known to mediate MMP expression. Infection with H. pylori, a Gram-negative bacterium, is associated with gastric cancer development. A toxic factor induced by H. pylori infection is reactive oxygen species (ROS), which activate MAPK signaling in gastric epithelial cells. Peroxisome proliferator-activated receptor γ (PPAR-γ) mediates the expression of antioxidant enzymes including catalase. β-Carotene, a red-orange pigment, exerts antioxidant and anti-inflammatory properties. We aimed to investigate whether β-carotene inhibits H. pylori-induced MMP expression and cell invasion in gastric epithelial AGS (gastric adenocarcinoma) cells. We found that H. pylori induced MMP-10 expression and increased cell invasion via the activation of MAPKs and AP-1 in gastric epithelial cells. Specific inhibitors of MAPKs suppressed H. pylori-induced MMP-10 expression, suggesting that H. pylori induces MMP-10 expression through MAPKs. β-Carotene inhibited the H. pylori-induced activation of MAPKs and AP-1, expression of MMP-10, and cell invasion. Additionally, it promoted the expression of PPAR-γ and catalase, which reduced ROS levels in H. pylori-infected cells. In conclusion, β-carotene exerts an inhibitory effect on MAPK-mediated MMP-10 expression and cell invasion by increasing PPAR-γ-mediated catalase expression and reducing ROS levels in H. pylori-infected gastric epithelial cells.     

Antimelanogenic and Antimigration Properties of the Ethyl Acetate Fraction of Calendula officinalis Flowers on Melanoma Cells

Calendula officinalis L., commonly known as marigold, is not only cultivated for ornamental purposes but is also used as a traditional medicinal herb. Its flowers have been used to treat various skin diseases, including rashes, burns, cuts and bruises, since ancient times. However, to our knowledge, the impact of C. officinalis L. on melanoma and its mechanism have not been clarified. The aim of this work was to investigate the chemical characterization and antimelanogenic and antimigration activities of the ethyl acetate fraction of C. officinalis flowers (EFC), as well as elucidate the potential mechanism. The obtained results showed that EFC markedly decreased α‐MSH‐induced melanin production and the cell migration ability of melanoma cells in a dose‐dependent manner. Additionally, EFC significantly inhibited the activity and expression of matrix metalloproteinase 2 (MMP‐2) via suppressing the mitogen‐activated protein kinase (MAPK) signaling pathway. Taken together, the present study demonstrated that C. officinalis flowers can be used as a natural source of antimelanogenisis and antimigration regent to treatment or prevent skin diseases.     

The HGF-met signaling axis: emerging themes and targets of inhibition

The Met tyrosine kinase receptor is the only known receptor for hepatocyte growth factor (HGF). Downstream Met signaling is essential for embryonic development; however, aberrant Met signaling promotes tumor progression by facilitating cell proliferation, survival, migration, invasion, and metastasis. Tumor cell invasion is considered an important step in distant metastatic foci formation. Several recent reviews have focused on the pleiotropic effects of Met signaling in both tumor cells and in the surrounding stromal cells. This review will summarize the currently described mechanisms driving Met induced tumor cell progression and invasion, the role played by cells in the tumor stroma, and therapeutic approaches to block receptor activity. In addition, this review will also highlight two new areas of development: 1) attenuation of Met signaling via multiple mechanisms of action targeting tumor cells and cells in the surrounding stroma using plant-derived polyphenols and 2) the induction by HGF of atypical lysosome trafficking, leading to increased protease secretion and tumor cell invasion. These new areas of research will help to uncover novel therapeutic targets to block the HGF/Met signaling axis to slow cancer progression.     

Anti-Cancer Effects of α-Cubebenoate Derived from Schisandra chinensis in CT26 Colon Cancer Cells

α-Cubebenoate derived from Schisandra chinensis has been reported to possess anti-allergic, anti-obesity, and anti-inflammatory effects and to exhibit anti-septic activity, but its anti-cancer effects have not been investigated. To examine the anti-cancer activity of α-cubebenoate, we investigated its effects on the proliferation, apoptosis, and metastasis of CT26 cells. The viabilities of CT26 cells (a murine colorectal carcinoma cell line) and HCT116 cells (a human colon cancer cell line) were remarkably and dose-dependently diminished by α-cubebenoate, whereas the viability of CCD-18Co cells (a normal human fibroblast cell line) were unaffected. Furthermore, α-cubebenoate treatment increased the number of apoptotic CT26 cells as compared with Vehicle-treated cells and increased Bax, Bcl-2, Cas-3, and Cleaved Cas-3 protein levels by activating the MAP kinase signaling pathway. α-Cubebenoate also suppressed CT26 migration by regulating the PI3K/AKT signaling pathway. Furthermore, similar reductions were observed in the expression levels of some migration-related proteins including VEGFA, MMP2, and MMP9. Furthermore, reduced VEGFA expression was found to be accompanied by the phosphorylations of FAK and MLC in the downstream signaling pathway of adhesion protein. The results of the present study provide novel evidence that α-cubebenoate can stimulate apoptosis and inhibit metastasis by regulating the MAPK, PI3K/AKT, and FAK/MLC signaling pathways.     

The Bioflavonoid Galangin Suppresses the Growth of Ehrlich Ascites Carcinoma in Swiss Albino Mice: A Molecular Insight

Bioflavonoids are plant compounds touted for their potential to treat or prevent several diseases including cancer caused by various stress conditions. Galangin (4H-1-Benzopyran-4-one, 3, 5, 7-trihydroxy-2-phenyl-), a flavonoid, is a polyphenolic compound found primarily in medicinal herb, Alpinia galanga. This study aims to demonstrate the galangin as a pharmacological lead compound using in vitro, in vivo, and in silico model targeting specific cancer condition and proteins. The proliferation of MCF-7 and Ehrlich ascites carcinoma (EAC) cells was significantly inhibited with an IC₅₀ of 34.11 and 22.29???g/ml, respectively. In an animal model system, galangin has inhibited the tumor growth by 73.51%?±?4.742 in EAC-induced Swiss Albino mice with no evidences of mortality as compared to standard drug, 5-fluorouracil. The effectiveness of galangin is proven in an animal system suggesting its pharmacokinetics behavior in an animal model which is also complemented by outcome of in silico analysis with more than 88?% of human intestinal absorption and significant Caco-2 cell, MDCK cell, and skin permeability as predicted by in silico methods. Galangin was docked against 19 different proteins involved in tumorogenesis and apoptosis; the energetic analysis indicates that it exhibits higher predicted binding free energy of ?12.7?kcal/mol with Bcl-xL protein.     

Zinc oxide nanoparticle synthesized from Euphorbia fischeriana root inhibits the cancer cell growth through modulation of apoptotic signaling pathways in lung cancer cells

Lung cancer is the widespread carcinogenesis in men and the third most familiar cancer in women. It is one of the mostly aggressive human cancers, which is responsible for around 1.4 million deaths per annum and has utmost mortality and incidence with 1.8 million new incidences and 1.6 million new deaths yearly. In this present study, we have evaluated the anticancer potential of zinc oxide nanopartices (ZnONPs) synthesized from a root extract of Euphorbia fischeriana (EF), through the apoptosis signaling markers in A549 lung cancer cells. The synthesized EF-ZnONPs were evaluated through the transmission electron microscope (TEM), Fourier transform infra red (FTIR), UV–visible spectroscopy and dynamic light scattering (DLS) techniques. The EF-ZnONPs were assessed for their cytotoxicity activity towards A549 cells by MTT test. The induction of apoptosis was analysed by the mitochondria membrane potential (MMP), reactive oxygen species (ROS), cell migration and dual staining. Furthermore, pro and anti-apoptotic signaling protein expression was evaluated by western blotting method. We found the bioformulated EF-ZnONPs has a spherical morphology and revealed the existence of diverse bioactive compounds. Also we found the cytotoxic effect of EF-ZnONPs. Apoptosis was activated by the EF-ZnONPs with improved ROS, decreased MMP, inhibited cell migration and altered dual staining was observed. Furthermore, the diminished expression of anti-apoptotic protein Bcl-2 was noted. In this study, we observed the formulation, characterization and anticancer potency of ZnONPs of EF plant extract (EF-ZnONPs) was useful for treatments of lung cancer.     

Angelica gigas NAKAI and Its Active Compound,Decursin, Inhibit Cellular Injury as an Antioxidant by the Regulation of AMP-Activated Protein Kinase and YAP Signaling

Natural products and medicinal herbs have been used to treat various human diseases by regulating cellular functions and metabolic pathways. Angelica gigas NAKAI (AG) helps regulate pathological processes in some medical fields, including gastroenterology, gynecology, and neuropsychiatry. Although some papers have reported its diverse indications, the effects of AG against arachidonic acid (AA)+ iron and carbon tetrachloride (CCl₄) have not been reported. In HepG2 cells, AA+ iron induced cellular apoptosis and mitochondrial damage, as assessed by mitochondrial membrane permeability (MMP) and the expression of apoptosis-related proteins. On the other hand, AG markedly inhibited these detrimental phenomena and reactive oxygen species (ROS) production induced by AA+ iron. AG activated the liver kinase B1 (LKB1)-dependent AMP-activated protein kinase (AMPK), which affected oxidative stress in the cells. Moreover, AG also regulated the expression of yes-associated protein (YAP) signaling as mediated by the AMPK pathways. In mice, an oral treatment of AG protected against liver toxicity induced by CCl₄, as indicated by the plasma and histochemical parameters. Among the compounds in AG, decursin had antioxidant activity and affected the AMPK pathway. In conclusion, AG has antioxidant effects in vivo and in vitro, indicating that natural products such as AG could be potential candidate for the nutraceuticals to treat various disorders by regulating mitochondrial dysfunction and cellular metabolic pathways.     

Betulinic Acid Restricts Human Bladder Cancer Cell Proliferation In Vitro by Inducing Caspase-Dependent Cell Death and Cell Cycle Arrest,and Decreasing Metastatic Potential

Betulinic acid (BA) is a naturally occurring pentacyclic triterpenoid and generally found in the bark of birch trees (Betula sp.). Although several studies have been reported that BA has diverse biological activities, including anti-tumor effects, the underlying anti-cancer mechanism in bladder cancer cells is still lacking. Therefore, this study aims to investigate the anti-proliferative effect of BA in human bladder cancer cell lines T-24, UMUC-3, and 5637, and identify the underlying mechanism. Our results showed that BA induced cell death in bladder cancer cells and that are accompanied by apoptosis, necrosis, and cell cycle arrest. Furthermore, BA decreased the expression of cell cycle regulators, such as cyclin B1, cyclin A, cyclin-dependent kinase (Cdk) 2, cell division cycle (Cdc) 2, and Cdc25c. In addition, BA-induced apoptosis was associated with mitochondrial dysfunction that is caused by loss of mitochondrial membrane potential, which led to the activation of mitochondrial-mediated intrinsic pathway. BA up-regulated the expression of Bcl-2-accociated X protein (Bax) and cleaved poly-ADP ribose polymerase (PARP), and subsequently activated caspase-3, -8, and -9. However, pre-treatment of pan-caspase inhibitor markedly suppressed BA-induced apoptosis. Meanwhile, BA did not affect the levels of intracellular reactive oxygen species (ROS), indicating BA-mediated apoptosis was ROS-independent. Furthermore, we found that BA suppressed the wound healing and invasion ability, and decreased the expression of Snail and Slug in T24 and 5637 cells, and matrix metalloproteinase (MMP)-9 in UMUC-3 cells. Taken together, this is the first study showing that BA suppresses the proliferation of human bladder cancer cells, which is due to induction of apoptosis, necrosis, and cell cycle arrest, and decrease of migration and invasion. Furthermore, BA-induced apoptosis is regulated by caspase-dependent and ROS-independent pathways, and these results provide the underlying anti-proliferative molecular mechanism of BA in human bladder cancer cells.     

Syntenin increases the invasiveness of small cell lung cancer cells by activating p38, AKT,focal adhesion kinase and SP1

Syntenin is a PDZ domain-containing adaptor protein that has been recently shown to regulate migration and invasion in several tumors. Small cell lung cancer (SCLC) is notorious for its invasiveness and strong potential for metastasis. We therefore studied the influence of syntenin on the invasiveness of SCLC. Immunohistochemistry in tumor tissues showed that syntenin was more frequently expressed in small cell carcinomas than other neuroendocrine tumors, such as carcinoids and neuroblastomas, suggesting that syntenin expression may be related to more aggressive forms of neuroendocrine tumors. In SCLC patients, syntenin overexpression in tumor cells was significantly associated with more extensive and advanced disease at the time of diagnosis (P=0.029). Overexpression of syntenin in SCLC cells that were intrinsically syntenin-low increased the invasiveness of cells and led to the induction of extracellular matrix (ECM)-degrading membrane type 1-matrix metalloproteinase (MT1-MMP) and matrix metalloproteinase 2 (MMP2). In contrast, suppression of syntenin in syntenin-high cells was associated with the downregulation of MT1-MMP. Contrary to the results of previous studies using malignant melanomas and breast carcinomas, signaling cascades were shown to be further transduced through p38 MAPK and PI3K/AKT, with activation of SP1 rather than NF-κB, under circumstances not involving ECM interaction. In addition, the upstream molecule focal adhesion kinase was induced by syntenin activation, in spite of the absence of ECM interaction. These results suggest that syntenin might contribute to the invasiveness of SCLC and could be utilized as a new therapeutic target for controlling invasion and metastasis in SCLC.