Cell Adhesion ; drug effects ; Cell Movement ; drug effects ; Focal Adhesion Kinase 1 ; genetics ; metabolism ; Focal Adhesion Protein-Tyrosine Kinases ; Neoplasms ; Phosphorylation

Animals ; Colonic Neoplasms ; metabolism ; pathology ; Focal Adhesion Kinase 1 ; Focal Adhesion Protein-Tyrosine Kinases ; Humans ; Integrins ; metabolism ; Neoplasm Invasiveness ; Neoplasm Metastasis ; Protein-Tyrosine Kinases ; metabolism ; Rectal Neoplasms ; metabolism ; pathology ; Signal Transduction

Cell migration plays an important role in repair of injury, angiogenesis, cancer metastasis and so on. In this paper the effects of basic fibroblast growth factor (bFGF) of different concentrations on ECV-304 cell migration, and the dynamic changes in focal adhesion kinase (FAK) were observed. The relationship between FAK and cell migration induced by bFGF was studied. A ECV-304 cell scratch wound model was established and the images of cell migration were quantitatively measured using a computer-assisted videomicroscopic system. The dynamic changes in FAK content (Western blot), FAK activity (immunoprecipitation plus Western blot) and FAK mRNA (RT-PCR) were measured in vitro. The expression of integrin alpha3 was investigated using immunocytochemical staining (ABC method). The results showed that bFGF produced a dual-phase regulatory effect on ECV-304 migration when the cell confluent areas reached 90%-95% in culture. It was found that compared with the control group (0 ng/ml bFGF), the cell migration was stimulated (P<0.05), inhibited (P<0.05) and unchanged when the cultured cells were treated with bFGF at the concentrations of 5, 10 and 15 ng/ml, respectively. The content and activity of FAK protein were markedly up-regulated in 5 ng/ml bFGF group and down-regulated in 15 ng/ml bFGF group, respectively. FAK mRNA expression came to the peak in 5 ng/ml bFGF group after 6 h culture and there was a significant difference compared with the control group. In various experimental groups there were no significant differences in the expression of integrin alpha3 compared with the control group according to the immunocytochemical staining. The results mentioned above suggest that different concentrations of bFGF have a dual-phase effect on the migration of cultured ECV-304 cells, which correlates positively with FAK content, activity and mRNA in cultured ECV-304 cell scratch wound model. The FAK plays an important role in the signal transduction pathway of cell migration induced by bFGF, while bFGF can regulate the content of FAK in ECV-304 cells at gene transcription level.
Cell Movement ; physiology ; Cells, Cultured ; Endothelium, Vascular ; cytology ; Fibroblast Growth Factor 2 ; physiology ; Focal Adhesion Kinase 1 ; Focal Adhesion Protein-Tyrosine Kinases ; Humans ; Integrin alpha3 ; metabolism ; Protein-Tyrosine Kinases ; metabolism ; RNA, Messenger ; metabolism ; Umbilical Veins ; cytology

OBJECTIVESTo investigate the effects of Arg-Gly-Asp-Ser (RGDS) tetrapeptide on integrin signaling and apoptosis in fibronectin (FN) -stimulated hepatic stellate cells (HSCs).

METHODS3H-thymidine incorporation, annexin-V/propidium iodide double-labeled flow cytometry (FCM) and transmission electron microscopy were employed to estimate the influence of RGDS on the proliferation and apoptosis of HSCs. And the adhesion rates were observed by toluidine blue colorimetric assay. The expression of focal adhesion kinase (FAK) mRNA and protein in HSCs was detected using RT-PCR and western blotting analysis, respectively.

RESULTSRGDS tetrapeptide at the concentrations of 25 microg/ml, 50 microg/ml and 100 microg/ml inhibited the proliferation of HSCs and induced HSCs apoptosis in dose-dependent and time-dependent manners, with the apoptotic rates of 9.49%, 27.67%, 31.59%, and the necrotic rates of 3.47%, 5.38%, 9.10%, respectively. Both the rates were higher than those in FN group (apoptotic rate: 3.44%; necrotic rate: 2.39%), F=8.02, P<0.05. After adding RGDS tetrapeptide to HSCs for 2 hours, the adhesive inhibition rates were 8.82%, 29.41% and 45.59%, respectively, which were higher than that in FN group (F=20.58, P<0.01). After exposure of HSCs to RGDS tetrapeptide for 24 hours, FAK protein decreased, and FAK mRNA was down-regulated earlier, about 2 hours after exposure to RGDS tetrapeptide.

CONCLUSIONThese results suggest that RGDS tetrapeptide may induce apoptosis of HSC in both dose-dependent and time-dependent manners in vitro, which may be related to the disruption of cell matrix adhesion and down-regulation of FAK expression.

Apoptosis ; drug effects ; Fibronectins ; pharmacology ; Focal Adhesion Kinase 1 ; Focal Adhesion Protein-Tyrosine Kinases ; Hepatocytes ; cytology ; physiology ; Humans ; Integrins ; metabolism ; physiology ; Liver ; cytology ; physiology ; Oligopeptides ; pharmacology ; Platelet Aggregation Inhibitors ; pharmacology ; Protein-Tyrosine Kinases ; biosynthesis ; genetics ; metabolism ; Signal Transduction

Angiotensin II ; pharmacology ; Cells, Cultured ; Focal Adhesion Protein-Tyrosine Kinases ; metabolism ; Humans ; Myocytes, Smooth Muscle ; cytology ; Pulmonary Artery ; cytology

OBJECTIVETo investigate the effect of gastrin on invasiveness of human colon cancer cells and the role of gastrin receptor-focal adhesion kinase (FAK) signal transduction pathway in this proess.

METHODSpCR3.1/GR vector expressing gastrin receptor was transfected into a colorectal cancer cell line Colo320 with lipofectamine 2000, and screened by G418. The expression levels of gastrin receptor of the parental cell line Colo320 and the transfected cell line Colo320/GR were assayed by RT-PCR. On the other hand, antisense oligonucleotide of FAK was used to block its expression. The mock transfected Colo320 and sense oligonucleotide Colo320 cells were used as controls. Colo320 and Colo320/GR cells were treated with increasing doses (0 approximately 100 nmol/L) of gastrin. Invasiveness of Colo320 and Colo320/GR cells was determined by Boyden chamber. Phosphorylation of focal adhesion kinase (FAK) tyr-397 was examined by immunoprecipitation and Western-blot.

RESULTSRT-PCR results showed that the Colo320/GR cells had an mRNA level four times as high as that of Colo320 cells. Western blot showed that FAK tyr397 phosphorylation of Colo320 cells was apparently decreased. Colo320 and Colo320/GR cells showed a dose-dependent response to gastrin on invasiveness and phosphorylation of FAK tyr-397. Invasiveness of Colo320 cells reached its climax when concentration of gastrin was 100 nmol/L, and FAK tyr-397 phosphorylation was marked when concentration of gastrin was 10 nmol/L, but the latter decreased when gastrin concentration was increased to 100 nmol/L. Colo320/GR cells had the same tendency as Colo320 cells, but showed an even stronger invasiveness and a higher level of FAK tyr-397 phosphorylation than Colo320 cells. Before gastrin stimulation, the invasiveness of Colo320 cells transfected with antisense oligonucleotides and the controls showed no difference. After gastrin stimulation, the increase in invasiveness was much less than that in the controls.

CONCLUSIONGastrin can evidently promote invasiveness of Colo320 cells via gastrin-gastrin receptor-FAK signal transduction pathway.

Cell Line, Tumor ; Colorectal Neoplasms ; pathology ; Focal Adhesion Protein-Tyrosine Kinases ; metabolism ; Gastrins ; pharmacology ; Humans ; Neoplasm Invasiveness ; Signal Transduction

OBJECTIVETo investigate the role of cytoplasmic domain of integrin alpha IIb in platelet signal transduction.

METHODSBinding capacity of integrin alpha IIb(R995A) to antibody platelet activation complex-1 (PAC-1) and pp125 focal adhesion kinase (FAK) phosphorylation of cells were detected by flow cytometry, immune precipitation, and Western blotting.

RESULTSWithout activation, wild-type alpha IIb beta3 Chinese hamster ovary (CHO) cells failed to bind to PAC-1, but mutant chimera alpha IIb(R995A)beta3 CHO cells were able to bind with PAC-1. Furthermore, phosphorylation of pp125 (FAK) in wild-type alpha IIb beta3 CHO cells occured only when cells were adhered to fibrinogen, but could not be detected in bovine serum albumin suspension. However in the mutant chimera group, it could be detected in both conditions.

CONCLUSIONThe mutation in integrin alpha IIb(R995A) alters its affinity state as a receptor, thus also mediating cytoplasmic signal transduction leading to the phosphorylation of pp125 (FAK) without ligand binding.

Animals ; Blood Platelets ; metabolism ; CHO Cells ; Cell Adhesion ; Cricetinae ; Cricetulus ; Cytoplasm ; metabolism ; Dual Specificity Phosphatase 2 ; Focal Adhesion Kinase 1 ; Focal Adhesion Protein-Tyrosine Kinases ; Humans ; Phosphorylation ; Platelet Glycoprotein GPIIb-IIIa Complex ; genetics ; metabolism ; physiology ; Point Mutation ; Protein Phosphatase 2 ; Protein Tyrosine Phosphatases ; metabolism ; Protein-Tyrosine Kinases ; metabolism ; Signal Transduction ; Transfection

Focal adhesion kinase (FAK) plays a critical role in the process of cell adhesion and migration by regulating the expression of downstream small G proteins. A kind of focal adhesion kinase (FAK) inhibitor was used to inhibit the phosphorylation of Y397 site of FAK, and scratch wound migration assay was used to examine the effect of FAK inhibitor with different concentrations (0-250 nmol/mL) on the migration of hepatomal cells (Hep G2 cells) at 0, 2, 4, 8 and 24h. Immunofluorescence analysis and Western blot analysis were performed to detect the expression of F-actin and small G proteins Rac1, RhoA and Cdc42 in Hep G2 cells treated with FAK inhibitor for 120 min. The results indicated that the FAK inhibitor can inhibit the migration of Hep G2 cells with a dose- and time-dependent manner. F-actin was down-regulated in Hep G2 cells treated with FAK inhibitor for 120 min, and expression of small G proteins were inhibited at different durations. The inhibition of FAK phosphorylation could inhibit cell adhesion and migration by down-regulating small G proteins. These results suggested that FAK inhibitor can inhibit the migration of tumor cells by blocking FAK phosphorylation. This means that FAK inhibitor can block the metastasis of tumor cells to surrounding tissues. It may be a potential application in the prevention and treatment of cancer.
Cell Adhesion ; drug effects ; Cell Movement ; drug effects ; Focal Adhesion Protein-Tyrosine Kinases ; antagonists & inhibitors ; metabolism ; physiology ; Hep G2 Cells ; Humans ; Liver Neoplasms ; pathology ; Neoplasm Metastasis ; prevention & control

Tumor angiogenesis induced by vascular endothelial cells (VECs) migration is a necessary condition for tumor growth and metastasis. The purpose of this study is to investigate the effect of focal adhesion kinase (FAK) inhibitor (50nmol/mL) on the adhesion and migration of endothelial cells(ECs) and the expression of focal adhesion proteins vinculin, talin and paxillin. Scratch wound migration assay was performed to examine the effect of FAK inhibitor with 50nmol/mL on ECs migration at 0, 5, 10, 30, 60 and 120min, respectively. And immunofluorescence analysis was performed to detect the expression of F-actin in ECs treated with FAK inhibitor within 2h. Western blot was carried out to determine the effect of FAK inhibitor on expression of vinculin, talin and paxillin proteins. The results showed that the migration distance and the expression of F-actin in ECs treated with FAK inhibitor decreased significantly compared with that of the controls, and the level of vinculin showed no significant difference with increasing of treated time of FAK inhibitor. However, the talin and paxillin showed an identical decreasing tendency in 5-10min, but slowly going up in 30min and then after subsequently decreasing. The results of this study proved that blocking phosphorylation of FAK could inhibit VECs adhesion and migration by downregulating focal adhesion proteins so that it may inhibit tumor angiogenesis. This may provide a new approach for tumor therapy.
Cell Adhesion ; Cell Movement ; physiology ; Cells, Cultured ; Endothelial Cells ; cytology ; metabolism ; Focal Adhesion Protein-Tyrosine Kinases ; antagonists & inhibitors ; metabolism ; Focal Adhesions ; metabolism ; physiology ; Humans ; Neoplasms ; blood supply ; Neovascularization, Pathologic ; Paxillin ; metabolism ; Talin ; metabolism ; Vinculin ; metabolism

OBJECTIVETo study the role of focal adhesion kinase (FAK) in the pathogenesis of human hypertrophic scar.

METHODSHuman hypertrophic scar fibroblasts (HSFB) were isolated from human hypertrophic scar and cultured in vitro. The cells were then divided into 3 groups as AT group (phosphorothioate FAK ASODN was transfected into the HSFB by liposome), LPC group (liposome only), and LC group (control group, without liposome or ASODN). The FAKmRNA index of HSFB was assessed by polymerase chain reaction method (FQ-PCR). The collagen synthesis of HSFB was assessed by 3H-proline incorporation method.

RESULTSThe FAK mRNA index of HSFB in AT group 48 hours after transfection was significantly lower than that in LPC and LC groups (0.043 +/- 0.030, 0.124 +/- 0.070, 0.127 +/- 0.0195, P < 0.05). The 3H-proline incorporation rate in AT group was lower than that in LPC and LC groups (257.0 +/- 15.14, 962.2 +/- 300.5, 930.8 +/- 28.97, P < 0.01).

CONCLUSIONThe expression of FAK gene and collagen synthesis of the cultured HSFB could be inhibited by FAK ASODN, indicating that FAK played a role in the development of excessive fibrosis of human hypertrophic scar.

Cells, Cultured ; Cicatrix, Hypertrophic ; genetics ; metabolism ; pathology ; Collagen ; biosynthesis ; Fibroblasts ; drug effects ; metabolism ; Focal Adhesion Protein-Tyrosine Kinases ; genetics ; metabolism ; Humans ; Oligonucleotides, Antisense ; genetics ; pharmacology ; Transfection