STAT3-independent inhibition of lysophosphatidic acid-mediated upregulation of connective tissue growth factor (CTGF) by cucurbitacin I

Cucurbitacins are recognised as anti-tumour agents because of their interference with STAT3 signalling, but may also affect the integrity of the actin cytoskeleton. In the present study the effect of cucurbitacin I was investigated in fibroblasts. In these cells, cucurbitacin I interfered with lysophosphatidic acid (LPA) signalling. It inhibited tyrosine phosphorylation of focal adhesion proteins and induction of connective tissue growth factor (CTGF), a potent profibrotic protein. Inhibition of Src family kinases with PP2, but not the inactive analogue PP3, also interfered with LPA-mediated tyrosine phosphorylation and induction of CTGF. Jak2-STAT3 signalling seemed to be the connecting link, because CTGF induction was sensitive to AG490, an inhibitor of Jak2, and cucurbitacin I, an inhibitor of Jak2 and STAT3. However, LPA did not activate tyrosine phosphorylation of STAT3. Furthermore, cucurbitacin I was as effective in STAT3 knock out cells as in control cells. Therefore, the inhibitory effect of cucurbitacin I was not related to inhibition of STAT3. Immunocytochemical analysis of cucurbitacin I-treated cells revealed disassembly of F-actin fibres, reorganisation into F-actin patches and resolution of focal adhesions. The phenotypic changes resembled changes observed after treatment of the cells with cytochalasin D, which has been shown to interfere with CTGF induction. Concentrations of cucurbitacin I, which have been shown to target Jak2-STAT3 signalling, thus, profoundly affect the actin cytoskeleton and may therefore modulate cell morphology, migration, adherence and gene expression also in non-tumour cells.     

Targeting vascular cell migration as a strategy for blocking angiogenesis: the central role of focal adhesion protein tyrosine kinase family

The formation of capillary-like structures during angiogenesis requires a series of well-orchestrated cellular events allowing endothelial cells and pericytes to migrate into the perivascular space. The proper activation of the migratory machinery in these cells is fine controlled by the presence of angiogenic challenges and by the interactions with extracellular matrix. The two members of the focal adhesion protein tyrosine kinases (FA-PTKs), FAK and PYK2, play a central role in modulating endothelial and vascular smooth muscle cells migration confirming the well consolidated observations in other migrating cell types. However accumulating data reveal that FAK and PYK2 are involved in several cell processes including cell proliferation and survival. FAK, once localized to focal adhesions, is thought to be one of the principal effectors in linking signals initiated by integrins and growth factor receptors to cytoskeleton, thus controlling migration. Although more obscure, and differently regulated, the function of PYK2 seems to be similar to that of FAK, but restricted to few cell types, including vasculature forming cells. FAK and PYK2 exert a primary role as adaptor proteins able to recruit, with high turnover, several proteins which in turn, through their docking domains and tyrosine kinase activity, determine both the turnover in focal adhesion assembly and the specificity of downstream signaling. The characterization of functional interactions of FA-PTKs may provide new potential therapeutic targets in order to control vascular pathological processes including angiogenesis.     

Bisphenol A induces focal adhesions assembly and activation of FAK,Src and ERK2 via GPER in MDA-MB-231 breast cancer cells

Bisphenol A (BPA) is an industrial synthetic chemical used in the production of polycarbonate plastics and epoxy resins. Human exposition to BPA is primarily through eating food, and drinking liquids, because BPA can leach from polycarbonate plastic containers, beverage cans and epoxy resins. BPA induces proliferation and migration in human breast cancer cells. The G protein-coupled estrogen receptor (GPER) is a G protein-coupled receptor coupled with Gs proteins that is activated by estrogen and estrogenic compounds and it is the receptor for BPA. However, the signal transduction pathways that mediate migration via BPA/GPER in triple negative breast cancer (TNBC) cells has not been studied in detail. Here, we demonstrate that BPA induces an increase of GPER expression and activation of FAK, Src and ERK2, and an increase of focal adhesion assembly via GPER in TNBC MDA-MB-231 cells. Moreover, BPA induces FAK and ERK2 activation, focal adhesion assembly and migration via epidermal growth factor receptor (EGFR) transactivation. Collectively our data showed that BPA via GPER and/or EGFR transactivation induces activation of signal transduction pathways that mediate migration in TNBC MDA-MB-231 cells.     

Focal adhesion kinase: a promising target for anticancer therapy

Focal adhesion kinase (FAK) is a protein tyrosine kinase acting as an early modulator of the integrin signalling cascade, thus regulating various basic cellular functions. In transformed cells, upregulation of FAK protein expression and uncontroled signalling were held responsible for the promotion of malignant phenotypic characteristics, as well as resistance to chemotherapy and radiotherapy. Direct FAK targeting resulted in the inhibition of the malignant phenotype of cancer cells, whereas increased apoptotic rates of cancer cells, either used alone or in combination with conventional chemotherapeutic agents, radiotherapy or hormonal therapy. Furthermore, drugs used in cancer chemotherapy, besides their basic mode of action, were also shown to act through altering FAK signalling. Finally, positive results were noted by the transfection of cancer cells with fak mutants or genes that suppress FAK expression or activity, such as phosphatase and tensin homolog deleted on chromosome Ten (PTEN), ribonucleotide reductase M1 polypeptide (RRM1) and melanoma differentiation-associated gene-7 (mda-7). The purpose of this article is a comprehensive review of the existing data on the possible use of FAK targeting in anticancer therapy.     

Focal adhesion kinase: a promising target for anticancer therapy

Focal adhesion kinase (FAK) is a protein tyrosine kinase acting as an early modulator of the integrin signalling cascade, thus regulating various basic cellular functions. In transformed cells, upregulation of FAK protein expression and uncontroled signalling were held responsible for the promotion of malignant phenotypic characteristics, as well as resistance to chemotherapy and radiotherapy. Direct FAK targeting resulted in the inhibition of the malignant phenotype of cancer cells, whereas increased apoptotic rates of cancer cells, either used alone or in combination with conventional chemotherapeutic agents, radiotherapy or hormonal therapy. Furthermore, drugs used in cancer chemotherapy, besides their basic mode of action, were also shown to act through altering FAK signalling. Finally, positive results were noted by the transfection of cancer cells with fak mutants or genes that suppress FAK expression or activity, such as phosphatase and tensin homolog deleted on chromosome Ten (PTEN), ribonucleotide reductase M1 polypeptide (RRM1) and melanoma differentiation-associated gene-7 (mda-7). The purpose of this article is a comprehensive review of the existing data on the possible use of FAK targeting in anticancer therapy.     

Protein kinase signaling in the modulation of microvascular permeability

The permeability of exchange microvessels is regulated through complex interactions between signaling molecules and structural proteins in the endothelium. Endothelial barrier integrity is maintained by adhesive interactions occurring at the cell-cell and cell-matrix contacts via junctional proteins and focal adhesion complexes that are anchored to the cytoskeleton. Cyclic AMP (cAMP) and cAMP-dependent kinase counteract with the nitric oxide (NO)-cyclic GMP (cGMP) pathway to protect the basal barrier function. Upon stimulation by physical stress, growth factors, or inflammatory agents, endothelial cells undergo a series of intracellular signaling reactions involving activation of protein kinase C (PKC), protein kinase G (PKG), mitogen-activated protein kinases (MAPK), and/or protein tyrosine kinases. The phosphorylation cascades trigger biochemical and conformational changes in the barrier structure and ultimately lead to an opening of the paracellular pathway. In particular, myosin light chain kinase (MLCK) activation and subsequent myosin light chain (MLC) phosphorylation in endothelial cells directly result in cell contraction and shape changes. The phosphorylation of beta-catenin may cause disorganization of adherens junctions or dissociation of vascular endothelial (VE)-cadherin-catenin complex from its cytoskeletal anchor, leading to loose or opened intercellular junctions. Additionally, focal adhesion kinase (FAK) phosphorylation-coupled focal adhesion assembly and redistribution provide an anchorage support for the conformational changes occurring in the cells and at the cell junctions. The Src family tyrosine kinases may serve as common signals that coordinate these molecular events to facilitate the paracellular transport of macromolecules. The critical roles of protein kinases in endothelial hyperpermeability implicate the therapeutic significance of protein kinase inhibitors in the prevention and treatment of diseases and injuries that are associated with microvascular barrier dysfunction.     

Effects of monocrotaline pyrrole and thrombin on pulmonary endothelial cell junction and matrix adhesion proteins

Previous work in our laboratory has shown that monocrotaline pyrrole (MCTP) interacts with actin and potentiates thrombin-mediated endothelial barrier permeability through increasing the overall surface area of intercellular gaps. To better characterize endothelial barrier leak in this model, we examined the effects of MCTP and thrombin on the localization and structure of three adhesion associated proteins that directly or indirectly interact with actin in regulating barrier function: cell-cell occludens junction molecule (ZO-1), the cell-cell adherens junction linker, ss-catenin, and the cell-matrix intermediary signaling protein, focal adhesion kinase (FAK). Immunohistochemistry demonstrated that thrombin treatment resulted in radial reorganization of focal adhesions and broader distribution of adherens and occludins junctions at the cell border suggestive of membrane stretching in contracture. MCTP pretreatment resulted in fewer and more disorganized focal adhesions and marked thinning of occludins and adherens junctions. MCTP pretreatment also interfered with thrombin stimulated junctional reorganization. Western blot analysis showed thrombin stimulated catalysis of ZO-1 and FAK while MCTP pretreatment resulted in FAK fragmentation similar to previous reports for apoptosis. We conclude that both MCTP and thrombin alter critical endothelial cell adhesion molecules and this may be an underlying mechanism for the potentiating effect MCTP has on thrombin induced vascular permeability in vitro.     

2,3,7,8-tetrachlorodibenzo-p-dioxin and epidermal growth factor cooperatively suppress peroxisome proliferator-activated receptor-gamma1 stimulation and restore focal adhesion complexes during adipogenesis: selective contributions of Src, Rho, and Erk distinguish these overlapping processes in C3H10T1/2 cells

Stimulation of PPARgamma1 and adipogenesis in multipotential C3H10T1/2 cells by the combination of dexamethasone and 3-isobutyl-1-methylxanthine (DM) is suppressed by 2,3,7,8 tetrachlorodibenzodioxin (TCDD) (10 nM). This suppression requires sustained activation of extracellular signal-regulated kinase (Erk)1/2. We show that it arises from an effect of TCDD on epidermal growth factor (EGF) signaling. DM initiates an early loss of cell adhesion that is reversed by this TCDD/EGF synergy. Src kinase activity was completely essential for adhesion restoration, sustained Erk activation, and suppression of peroxisome proliferator-activated receptor (PPAR)gamma1. MEK/Erk activity did not contribute, however, to TCDD-induced adhesion. Stimulation of adhesion may therefore precede elevation of Erk. Adhesion is produced by interaction of alphabeta integrins with extracellular matrix proteins and subsequent Src-mediated phosphorylation of focal adhesion kinase (FAK, Tyr576/577) and paxillin (Tyr118). TCDD enhanced the steady state Src-mediated phosphorylation of FAK but not of paxillin. Protein tyrosine phosphatase (PTPase) inhibition by orthovanadate (OVA) showed that this Src activity is highly restricted by PTPases. Partial inhibition of PTPases by OVA mimicked TCDD in producing EGF- and Src-dependent effects on cell adhesion and PPARgamma1 suppression. TCDD may therefore induce a protein that enhances Src effectiveness at adhesion sites. Rho kinase (ROCK) inhibition blocked TCDD/EGF stimulation of clustered focal adhesion complexes without affecting either sustained Erk activation or suppression of PPARgamma1. Thus, this ROCK-mediated clustering of integrin complexes is not needed for the effects of TCDD on Erk and PPARgamma1. A minimal cholesterol depletion with beta-methylcyclodextrin attenuated TCDD effects on PPARgamma1 and Erk activation. TCDD intervention is therefore linked to extracellular proteins. It indicates that TCDD-enhanced stimulation of EGF signaling to Erk may derive from the initial alphabeta integrin complexes.     

Focal adhesion kinase as a cancer therapy target

Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase that resides at the sites of focal adhesions. The 125 kDa FAK protein is encoded by the FAK gene located on human chromosome 8q24. Structurally, FAK consists of an amino-terminal regulatory FERM domain, a central catalytic kinase domain, and a carboxy-terminal focal adhesion targeting domain. FAK has been shown to be an important mediator of cell adhesion, growth, proliferation, survival, angiogenesis and migration, all of which are often disrupted in cancer cells. Normal tissues have low expression of FAK, while primary and metastatic tumors significantly overexpress this protein. This review summarizes expression of FAK by immunohistochemical staining in different tumor types and presents several FAK inhibition therapy approaches.     

Focal adhesion kinase and protein kinase B cooperate to suppress doxorubicin-induced apoptosis of breast tumor cells

Focal adhesion kinase (FAK) is up-regulated in a variety of cancers, including breast cancer, in association with poor disease prognosis. In the present study, we examined the role of FAK in the control of anticancer drug-induced apoptosis of mammary adenocarcinoma MTLn3 cells. Doxorubicin caused the formation of well defined focal adhesions and stress fibers early after treatment, which was later followed by their loss in association with the onset of apoptosis. Phosphorylation of FAK on tyrosine 397 decreased only during the onset of doxorubicin-induced apoptosis in a Bcl-2 and caspase-independent manner. Doxorubicin also caused an early activation of protein kinase B (PKB). Expression of the dominant-negative acting focal adhesion kinase-related nonkinase (FRNK) sensitized MTLn3 cells to apoptosis caused by doxorubicin. FRNK inhibited the doxorubicin-induced activation of PKB. In addition, inhibition of phosphatidylinositide-3 (PI-3) kinase with wortmannin inhibited the activation of PKB by doxorubicin. Both wortmannin and transient overexpression of the dual lipid/protein phosphatase and tensin homolog deleted on chromosome 10 enhanced doxorubicin-induced cell death. Altogether, these data fit with a model wherein FAK is involved in the doxorubicin-induced activation of the PI-3 kinase/PKB signaling route, thereby suppressing the onset of apoptosis caused by doxorubicin.     

Focal adhesion kinase and its signaling pathways in cell migration and angiogenesis

Focal adhesion kinase (FAK) is a cytoplasmic tyrosine kinase that plays critical roles in integrin-mediated signal transductions and also participates in signaling by other cell surface receptors. In integrin-mediated cell adhesion, FAK is activated via disruption of an auto-inhibitory intra-molecular interaction between its amino terminal FERM domain and the central kinase domain. The activated FAK forms a complex with Src family kinases, which initiates multiple downstream signaling pathways through phosphorylation of other proteins to regulate different cellular functions. Multiple downstream signaling pathways are identified to mediate FAK regulation of migration of various normal and cancer cells. Extensive studies in cultured cells as well as conditional FAK knockout mouse models indicated a critical role of FAK in angiogenesis during embryonic development and cancer progression. More recent studies also revealed kinase-independent functions for FAK in endothelial cells and fibroblasts. Consistent with its roles in cell migration and angiogenesis, increased expression and/or activation of FAK are found in a variety of human cancers. Therefore, small molecular inhibitors for FAK kinase activity as well as future development of novel therapies targeting the potentially kinase-independent functions of FAK are promising treatments for metastatic cancer as well as other diseases.     

FAK/Src family of kinases: protective or aggravating factor for ischemia reperfusion injury in nervous system?

Introduction: The focal adhesion kinase (FAK) and the Src families of kinases are subfamilies of the non-receptor protein tyrosine kinases. FAK activity is regulated by gene amplification, alternative splicing and phosporylation/dephosphorylation. FAK/Src complex has been found to participate through various pathways in neuronal models of ischemia-reperfusion injury (IRI) with conflicting results. The aim of the present review is to summarize the currently available data on this subject.

Areas covered: The MEDLINE/PubMed database was searched for publications with the medical subject heading IRI and FAK and/or Src, nervous system. We restricted our search till 2014. We identified 93 articles that were available in English as abstracts or/and full-text articles that were deemed appropriate for our review.

Expert opinion: FAK has been found to have a beneficial preconditioning effect on IRI through activation via the protein kinase C (PKC) pathway by anesthetic agents. Of great importance are the interactions between FAK/Src and VEGF that has been already detected as a protective mean for IRI. The effect of VEGF administration might depend on dose as well as on time of administration. A Ca²⁺/calmodulin-dependent protein kinase II or PKC inhibitors seem to have protective effects on IRI by inhibiting ion channels activation.     

Amelioration of neutrophil membrane function underlies granulocyte-colony stimulating factor action in glycogen storage disease 1b

Glycogen storage disease (GSD) 1b is a metabolic disorder characterized by a deficiency of glucose 6-phosphate transporter and neutrophil alterations, which are reduced in number and functionally impaired. The present study aimed at investigating neutrophil dysfunction correlating submembrane and cytoskeletal changes at different ages with or without granulocyte-colony stimulating factor (G-CSF) treatment. GSD1b neutrophils showed reduced expression and diffused localization of focal adhesion kinase (FAK) and actin. No abnormalities were observed in GSD1a patient neutrophils. Gelsolin was also slightly reduced in neutrophils of GSD1b patients. When patients were treated for at least 3 months with G-CSF, the neutrophil number and the expression of FAK and actin were significantly increased. Granulocyte colony-stimulating factor treatment was similarly effective when performed in 1 year old patients. FAK auto- and IL-8-mediated phosphorylations were already affected as early as 1 year of age. G-CSF treatment also improved this alteration. Our data suggest that neutrophil dysfunction in GSD1b patients might be related to functional impairment and disorganization of proteins of the sub-membrane apparatus, and that G-CSF treatment counteracts neutropenia and prevents the progressive alterations of neutrophil sub-membrane proteins.     

Involvement of Rho signaling in PAR2-mediated regulation of neutrophil adhesion to lung epithelial cells

Protease-activated receptor 2 (PAR2) has been implicated in the pathogenesis of airway inflammation. We report that epithelial PAR2 stimulation with trypsin (0.05-1 U/ml) or an agonist peptide (SLIGKV-NH2, 1-100 microM) for 0.5-3 h dose- and time-dependently enhanced neutrophil adhesion to alveolar type II epithelial cells (A549 cells) and that this stimulation also induced the formation of epithelial actin filaments. Both responses in neutrophil adhesion and epithelial actin reorganization were reduced by a Rho inhibitor, mevastatin and by a Rho-associated kinase (ROCK) inhibitor, Y-27632 ((R)-(+)-trans-N-(4-Pyridyl)-4-(1-aminoethyl)-cyclohexanecarboxamide). Neutrophil adherence was also inhibited by an inhibitor of actin polymerization, cytochalasin D and a tyrosine kinase inhibitor, genistein. Further, the PAR2-mediated tyrosine phosphorylation of focal adhesion kinase (FAK), a major cytoskeleton protein, was detected, and this response was inhibited by mevastatin or Y-27632. These results suggest that PAR2 stimulation of alveolar epithelial cells enhances neutrophil adhesion presumably at least in part through Rho/ROCK signal-mediated actin cytoskeleton reorganization associated with the tyrosine phosphorylation of FAK.     

Targeting Pyk2 for therapeutic intervention

Importance of the field: The focal adhesion tyrosine kinases FAK and Pyk2 are uniquely situated to act as critical mediators for the activation of signaling pathways that regulate cell migration, proliferation and survival. By coordinating adhesion and cytoskeletal dynamics with survival and growth signaling, FAK and Pyk2 represent molecular therapeutic targets in cancer as malignant cells often exhibit defects in these processes.

Areas covered in this review: This review examines the structure and function of the focal adhesion kinase Pyk2 and intends to provide a rationale for the employment of modulating strategies that include both catalytic and extra-catalytic approaches that have been developed in the last 3 – 5 years.

What the reader will gain: Targeting tyrosine kinases in oncology has focused on the ATP binding pocket as means to inhibit catalytic activity and downregulate pathways involved in tumor invasion. This review discusses the available catalytic inhibitors and compares them to the alternative approach of targeting protein–protein interactions that regulate kinase activity.

Take home message: Development of specific catalytic inhibitors of the focal adhesion kinases has improved but significant challenges remain. Thus, approaches that inhibit the effector function of Pyk2 by targeting regulatory modules can increase specificity and will be a welcome asset to the therapeutic arena.     

Suppressive effect and mechanism of saxatilin, a disintegrin from Korean snake (Gloydius saxatilis), in vascular smooth muscle cells

RGD-peptides can inhibit the binding of ligands to certain β3 integrins, αIIbβ3 and αvβ3, both of which are involved in neointimal hyperplasia that contributes to atherosclerosis and restenosis of arterial walls. Saxatilin, a disintegrin from a Korean snake (Gloydius saxatilis), interacts with integrins αIIbβ3 and αvβ3. It suppressed the adhesion of human coronary artery smooth muscle cells (HCASMCs) to vitronectin with an IC₅₀ of 2.5 μM, and growth factor (PDGF-BB or bFGF)-induced proliferation was inhibited at an IC₅₀ of 25 μM. Saxatilin disassembled the actin cytoskeleton of focal adhesion and induced cell detachment. This disassembly of focal adhesion in saxatilin-treated HCASMCs involved caspase-induced paxillin degradation. Saxatilin temporally phosphorylated FAK and ERKs and affected the cell cycle of HCASMCs by increasing CDK inhibitors (p21 and p27) and reducing cyclins (D1/2 and E). These results may have significant implications for integrin antagonistic therapy used for the treatment of atherosclerosis and restenosis.     

Low-dose exposure of intestinal epithelial cells to formaldehyde results in MAP kinase activation and molecular alteration of the focal adhesion protein paxillin

We investigated the potential pathophysiological role of non-lethal formaldehyde concentrations on human intestinal epithelial HT-29 cells. Expression levels of actin, tubulin and detectable cytokeratin isoforms 5, 13, 18, 19 and 20 were not affected after 24h of exposure to 1mM formaldehyde. By contrast, cellular organization of cytoskeletal constituents was already changed after 60 min. Within 15 min, formaldehyde induced profound tyrosine phosphorylation of the focal adhesion protein paxillin and of proteins at about 120-130 kDa. Concomitantly, phosphorylation of ERK-1/2 and p38 MAP kinase occurred. Paxillin was not only tyrosine phosphorylated but underwent a sustained molecular weight shift representing serine/threonine phosphorylation that was independent of MAP kinase activity and EGF-R-mediated signalling. Our data show that exposure of intestinal epithelial cells to low-dose formaldehyde is followed by rapid and profound signalling events. The data suggest a modifier role of environmental or endogenous formaldehyde for epithelial cell functions.     

Multiplexed high content screening reveals that cigarette smoke condensate-altered cell signaling pathways are accentuated through FAK inhibition in human bronchial cells

The mechanisms by which cigarette smoke condensate (CSC) disrupts F-actin and decreases cell motility in human bronchial (BEAS-2B) cells were assessed. The hypothesis that CSC activated focal adhesion kinase (FAK), mitogen-activated protein kinases (MAPKs), and paxillin in BEAS-2B cells was tested. When BEAS-2B cells were treated with 20 to 100 μg/mL CSC for 1 hour, FAK increased. The CSC caused F-actin disruption, while FAK inhibition alone caused actin aggregates to collapse to the cell periphery, but FAK inhibition combined with CSC caused actin aggregates to distribute throughout the cells. The CSC treatment of BEAS-2B cells showed a dose-dependent increase in the activation of the MAPKs, c-Jun, JNK, ERK, p38, and heat shock protein 27 (Hsp27) and paxillin. Focal adhesion kinase phosphorylation inhibition combined with CSC treatment increased p38 and ERK at 1 hour and 24 hours along with decreased cell number and motility compared with CSC treatment alone. CSC exerts changes in BEAS-2B cells by altering morphology and activating MAPK pathways.     

Litebamine, a phenanthrene alkaloid from the wood of Litsea cubeba, inhibits rat smooth muscle cell adhesion and migration on collagen

Smooth muscle cells (SMCs) play an important role in the development of atherosclerosis and restenosis after angioplasty and coronary bypass grafting. The pathogenesis of these vascular diseases includes the abnormal production of extracellular matrix (ECM) proteins by SMCs and their interactions with this newly synthesized and preexisting ECM. Litebamine, a natural phenanthrene alkaloid from the wood of Litsea cubeba, has been shown to inhibit platelet aggregation and thromboxane B(2) formation, suggesting its antithrombotic activity. In the present study we examined litebamine effects on vascular SMC adhesion and migration. Our results indicated that litebamine inhibited rat aortic SMCs (RASMCs) and A10 thoracic SMCs adhesion to collagen but not to other matrix proteins, suggesting its specificity on collagen. This inhibition was possibly resulted from that litebamine attenuated immobilized collagen-induced focal adhesion kinase (FAK) phosphorylation and actin cytoskeleton reorganization in RASMCs, as determined by Western blotting and immunofluorescence microscopy. In a functional study, litebamine also inhibited platelet-derived growth factor (PDGF)-induced RASMC migration but did not affect PDGF-induced matrix metalloproteinases (MMPs) secretion. Strikingly, among the tested kinases involved in PDGF-induced migration, only PDGF-induced phosphatidylinositol-3 kinase (PI-3K) activation was inhibited by litebamine. Taken together, we demonstrated here that litebamine can functionally inhibit vascular SMC adhesion and migration and elucidated its possible mechanisms of action. As SMC adhesion and migration are critical events in disease-related vascular remodeling, this compound may have beneficial effects in preventing cardiovascular diseases.