Cellular Microenvironment ; Humans ; Myocardial Infarction ; metabolism ; rho-Associated Kinases ; metabolism ; rhoA GTP-Binding Protein ; metabolism

PURPOSE: The Rho family of GTPases are involved in actin cytoskeleton organization and are associated with carcinogenesis and progression of human cancers. The clinicopathological significance of RhoA is not yet well known in the case of colorectal cancer. To investigate the expression of RhoA protein in colorectal carcinoma and to evaluate the relationship between RhoA protein expression and invasion and metastasis of colorectal cancer, we examined the expression of RhoA protein by using Western blotting and immunohistochemistry. METHODS: The protein levels of RhoA in colorectal carcinomas of surgical specimens were analyzed in 71 consecutive patients with colorectal cancers by using immunohistochemistry and Western blotting. The relationships between the protein levels of RhoA in tumor tissues and the clinicopathological features of the patients were also assessed. RESULTS: RhoA was highly expressed in 48 colorectal carcinomas (67.6%). There was a significant association between RhoA expression and lymph nodal status. The expression of RhoA protein was related to lymph-node metastasis (P=0.032) and advanced TNM tumor staging (P=0.020). RhoA expression had a significant prognostic value for overall survival. Kaplan-Meier plots of survival in patients with high RhoA showed that high RhoA expression was associated with a shorter overall survival. However, no association was found between RhoA and other pathologic or clinical variables, including age, gender, degree of differentiation, and presence of perineural spread. CONCLUSIONS: The RhoA protein may be related to malignant transformation and development of colorectal caricinomas and may play an important role in the invasion and the metastasis of colorectal carcinomas.
Actin Cytoskeleton ; Blotting, Western ; Colorectal Neoplasms ; GTP Phosphohydrolases ; Humans ; Immunohistochemistry ; Neoplasm Metastasis ; Neoplasm Staging ; rhoA GTP-Binding Protein

OBJECTIVETo investigate the mechanisms of lysophosphatidic acid (LPA) in stimulating invasion and metastatic colonization of ovarian cancer cells.

METHODSThe metastatic ability in vivo of ovarian cancer SK-OV3, HEY, OVCAR3, and IGROV1 cells was determined in tumor-bearing nude mouse models. Matrigel assay was used to detect the changes of response in vitro of ovarian cancer cells to LPA after Rac(-) or Rac(+) adenovirus treatment. LPA-induced Rho GTPase activation was detected by GST-fusion protein binding assay.

RESULTSThe peritoneal metastatic colonization assay showed overt metastatic colonization in mice receiving SK-OV3 and HEY cell inoculation, indicating that they are invasive cells. Metastatic colonization was not detected in animals receiving OVCAR3 and IGROV1 cells, indicating that these cells are non-invasive cells. In the matrigel invasion assay, exposure to LPA led to a notably greater migratory response in metastatic SK-OV3 and HEY cells (Optical density: SK-OV3 cells: 0.594±0.023 vs. 1.697±0.049, P<0.01; HEY cells: 0.804±0.070 vs. 1.851±0.095, P<0.01). But LPA did little in the non-metastatic OVCAR3 and IGROV1 cells (Optical density A: OVCAR3 cells: 0.336±0.017 vs. 0.374±0.007, P>0.05; IGROV1 cells: 0.491±0.036 vs. 0.479±0.061, P>0.05). LPA migratory responses of ovarian cancer cells were closely related to their metastatic colonization capabilities (r = 0.983, P<0.05). Rac(-) blocked the LPA response of invasive SK-OV3 and HEY cells (LPA-induced fold increase of cell migration: SK-OV3 cells: 2.988±0.095 vs. 0.997±0.100,P=0.01; HEY cells: 2.404±0.059 vs. 0.901±0.072, P=0.01). But Rac(+) confered the non-invasive cells with LPA response and invasion capability (LPA-induced fold increase of cell migration: OVCAR3 cells: 1.072±0.080 vs. 1.898±0.078, P<0.01; IGROV1 cells: 1.002±0.044 vs. 2.141±0.057, P<0.05). Among Rho GTPases, only Rac activation was different between ovarian cancer cell lines with different metastatic capability after LPA stimulation: Cdc42 could not be activated in both the invasive and non-invasive cell lines. RhoA could be activated in both the invasive and non-invasive cell lines. Rac could be activated by LPA in the invasive ovarian cancer cell lines. However, Rac could not be activated in the non-invasive cell lines.

CONCLUSIONLysophosphatidic acid stimulates invasion and metastasis of ovarian cancer cells through Rac activation.

Animals ; Cell Movement ; Female ; Humans ; Lysophospholipids ; metabolism ; Mice ; Ovarian Neoplasms ; metabolism ; Tumor Cells, Cultured ; rho GTP-Binding Proteins ; rhoA GTP-Binding Protein

Erectile dysfunction (ED) has been plaguing men for a long time and the incidence of this disease is as high as 52% among males aged between 40 and 70. Recent discovery has shown a connection between the RhoA/Rho-kinase signaling system and ED. This paper reviews the progress in the study of RhoA/Rho-kinase signaling pathway, expounds its mechanism in penile erection and provides a base for further research on the role of RhoA/Rho-kinase signaling pathway in penile erection.
Animals ; Humans ; Male ; Penile Erection ; physiology ; Rabbits ; Signal Transduction ; physiology ; rho-Associated Kinases ; metabolism ; rhoA GTP-Binding Protein ; metabolism

OBJECTIVE: To observe the effects of electroacupuncture (EA) at "Jiaji" (EX-B 2) points combined with nerve mobilization on protein and mRNA expression of RhoA in rabbits with sciatic nerve injury, and to provide theoretical basis for the treatment of peripheral nerve injury by EA at "Jiaji" (EX-B 2) points combined with nerve mobilization. METHODS: A total of 180 New Zealand rabbits were randomly divided into a normal control group, a model control group, a nerve mobilization group, an EA group, an EA plus nerve mobilization group, 36 rabbits in each group. Each group was further divided into a 1-week subgroup, 2-week subgroup and 4-week subgroup, 12 rabbits in each subgroup. The sciatic nerve injury model was made by clamping method. The rabbits in the normal control group did not receive any intervention. The rabbits in the model control group was normally fed after operation. The rabbits in the nerve mobilization group were treated with nerve mobilization; the manipulation lasted for 1 s and relaxed for 5 s, 10 times per day, 6 days per week. The rabbits in the EA group were treated with EA at "Jiaji" (EX-B 2) points (L-L), once a day, 30 min each time, 6 times per week. The rabbits in the EA plus nerve mobilization group were treated with EA at "Jiaji" (EX-B 2) points, followed by nerve mobilization. The function of sciatic nerve on the injured side was evaluated by toe tension reflex and modified Tarlov score; the tissues of corresponding segments of spinal cord L-L and sciatic nerve were taken; the expression of RhoA gene was detected by real-time PCR and the expression of RhoA protein was detected by Western Blot. RESULTS: ① Toe tension reflex and modified Tarlov score: at 1, 2 and 4 weeks, the scores in the model control group were lower than those in the normal control group (all <0.01). The scores in the subgroup of nerve mobilization group, EA group and EA plus nerve mobilization group were higher than those in the model control group (all <0.01), and the scores in the subgroup of EA plus nerve mobilization group were higher than those in the nerve mobilization group and the EA group (all <0.01); the recovery was the best at 4 weeks. ② The mRNA and protein expression of RhoA: in segment of spinal cord, at 1, 2 and 4 weeks, the expression in the model control group was higher than that in the normal control group (all <0.01). The expression in the subgroup of nerve mobilization group, EA group and EA plus nerve mobilization group was lower than that in the model control group (all <0.01), and the expression in the subgroup of EA plus nerve mobilization group was lower than that in the nerve mobilization group and the EA group (all <0.01); at 1 week and 4 weeks, the expression in the nerve mobilization group was lower than that in the EA group (all <0.01); at 2 weeks, the expression in the nerve mobilization group was higher than that in the EA group (all <0.01). In the sciatic nerve, at 1, 2 and 4 weeks, the expression in the model control group was higher than that in the normal control group (all <0.01). The expression in the subgroup of nerve mobilization group, EA group and EA plus nerve mobilization group was lower than that in the model control group (all <0.01); at 2 weeks and 4 weeks, the expression in the EA plus nerve mobilization group was lower than that in the nerve mobilization group and EA group (all <0.01); at 1 week, the expression in the nerve mobilization group was lower than that in the EA group and EA plus nerve mobilization group (all <0.01), but the differences between the EA group and the EA plus nerve mobilization group were not significant (>0.05); at 2 weeks, the expression in the nerve mobilization group was higher than that in the EA group (all <0.01); at 4 weeks, the expression in the nerve mobilization group was lower than that in the EA group (all <0.01). CONCLUSION The nerve mobilization and EA at "Jiaji" (EX-B 2) points could both promote the repair of injured sciatic nerve, which may be related to the down-regulation of RhoA expression, and the combination of the two methods has better effects.
Acupuncture Points ; Animals ; Chlorophenols ; Electroacupuncture ; Peripheral Nerve Injuries ; RNA, Messenger ; metabolism ; Rabbits ; Sciatic Nerve ; injuries ; rhoA GTP-Binding Protein

Low molecular weight GTP-binding proteins are molecular switches that are believed to play pivotal roles in cell growth, differentiation, cytoskeletal organization, and vesicular trafficking. Rab proteins are key players in the regulation of vesicular transport, while Rho family members control actin-dependent cell functions, i.e. the regulation of cytoskeletal organization in response to extracelluar growth factors and in dendritic neuron development. In this study, we have examined the regulation of small GTP-binding proteins that are implicated in neurosecretion and differentiation of neuron during ageing processes. Comparison of small GTP-binding proteins from the synaptosome and crude synaptic vesicles (LP2 membranes) of 2 months and 20 months old rat brain respectively showed no difference in the level of Rab family proteins (Rab3A and Rab5A). However, Rho family proteins such as RhoA and Cdc42 were elevated in LP2 membranes of the aged brain. The dissociation of Rab3A by Ca2+/calmodulin (CaM) from SV membranes was not changed during aging. Ca2+/CaM stimulated phosphorylation of the 22 and 55-kDa proteins in SV membranes from the aged rat brain, and inhibited phosporylation of 30-kDa proteins. GTPgammaS inhibited phosphorylation of the 100-kDa proteins and stimulated phosphorylation of the 70 kDa in LP2 membranes from both the young and aged rat brains, whereas GDPbetaS caused just the opposite reaction. These results suggest that protein phosphorylation and regulation of Rho family GTPases in rat brain appears to be altered during ageing processes.
*Aging ; Animal ; Brain/metabolism ; Calcium/pharmacology ; Cattle ; Comparative Study ; GTP-Binding Proteins/*metabolism ; Guanosine 5'-O-(3-Thiotriphosphate)/metabolism ; Molecular Weight ; Phosphorylation/drug effects ; Rats ; Rats, Sprague-Dawley ; Synaptic Membranes/*metabolism ; Synaptosomes/*metabolism ; cdc42 GTP-Binding Protein/biosynthesis/metabolism ; rab3A GTP-Binding Protein/metabolism ; rab5 GTP-Binding Proteins/metabolism ; rhoA GTP-Binding Protein/biosynthesis/metabolism

Low molecular weight GTP-binding proteins are molecular switches that are believed to play pivotal roles in cell growth, differentiation, cytoskeletal organization, and vesicular trafficking. Rab proteins are key players in the regulation of vesicular transport, while Rho family members control actin-dependent cell functions, i.e. the regulation of cytoskeletal organization in response to extracelluar growth factors and in dendritic neuron development. In this study, we have examined the regulation of small GTP-binding proteins that are implicated in neurosecretion and differentiation of neuron during ageing processes. Comparison of small GTP-binding proteins from the synaptosome and crude synaptic vesicles (LP2 membranes) of 2 months and 20 months old rat brain respectively showed no difference in the level of Rab family proteins (Rab3A and Rab5A). However, Rho family proteins such as RhoA and Cdc42 were elevated in LP2 membranes of the aged brain. The dissociation of Rab3A by Ca2+/calmodulin (CaM) from SV membranes was not changed during aging. Ca2+/CaM stimulated phosphorylation of the 22 and 55-kDa proteins in SV membranes from the aged rat brain, and inhibited phosporylation of 30-kDa proteins. GTPgammaS inhibited phosphorylation of the 100-kDa proteins and stimulated phosphorylation of the 70 kDa in LP2 membranes from both the young and aged rat brains, whereas GDPbetaS caused just the opposite reaction. These results suggest that protein phosphorylation and regulation of Rho family GTPases in rat brain appears to be altered during ageing processes.
*Aging ; Animal ; Brain/metabolism ; Calcium/pharmacology ; Cattle ; Comparative Study ; GTP-Binding Proteins/*metabolism ; Guanosine 5'-O-(3-Thiotriphosphate)/metabolism ; Molecular Weight ; Phosphorylation/drug effects ; Rats ; Rats, Sprague-Dawley ; Synaptic Membranes/*metabolism ; Synaptosomes/*metabolism ; cdc42 GTP-Binding Protein/biosynthesis/metabolism ; rab3A GTP-Binding Protein/metabolism ; rab5 GTP-Binding Proteins/metabolism ; rhoA GTP-Binding Protein/biosynthesis/metabolism

The aim of this study was to investigate the role of RhoA/mDia1 pathway in the process of thrombin-induced platelet aggregation and regulatory effect of PI3K inhibitor on this process. The human platelets were isolated from peripheral blood, the activation of RhoA, Rac1 and Cdc42 in the platelet aggregation was detected by GST pull-down assay and immune co-precipitation, the interaction of RhoA, Rac1 and Cdc42 with mDia1 and the formation of complex in the process of platelet aggregation were determined by immune coprecipitation, and the effect of PI3K inhibitor (wortmannin) on above-mentioned process was assayed. The results showed that thrombin elevated the activity of RhoA and the binding capability of RhoA with mDia1 during thrombin-induced platelet aggregation and spreading on Fg coated coverslips. Wortmannin inhibited the rising of RhoA activity and the binding level of RhoA with mDia1 induced by thrombin. Thrombin elevated the activity of Rac1 and Cdc42 during thrombin-induced platelet aggregation, but could not induce binding of Rac1 or Cdc42 with mDia1. Wortmannin could not inhibit the rising of Rac1 and Cdc42 activity induced by thrombin. It is concluded that the PI3-kinase regulates the thrombin-induced actin cytoskeleton reconstitution in platelets by RhoA-mDia1 pathway.
Actins ; metabolism ; pharmacology ; Adaptor Proteins, Signal Transducing ; immunology ; metabolism ; Blood Platelets ; metabolism ; Cells, Cultured ; Humans ; Phosphatidylinositol 3-Kinases ; pharmacology ; Platelet Aggregation ; drug effects ; Thrombin ; pharmacology ; rac1 GTP-Binding Protein ; metabolism ; rhoA GTP-Binding Protein ; metabolism ; pharmacology

Brain ; Cholesterol ; chemistry ; Cytoskeleton ; drug effects ; Endothelial Cells ; cytology ; metabolism ; Hemolysin Proteins ; chemistry ; pharmacology ; Humans ; Phalloidine ; pharmacology ; Pseudopodia ; drug effects ; Stress Fibers ; drug effects ; rac1 GTP-Binding Protein ; metabolism ; rhoA GTP-Binding Protein ; metabolism

We have shown that myosin light chain kinase (MLCK) was required for the off-contraction in response to the electrical field stimulation (EFS) of feline esophageal smooth muscle. In this study, we investigated whether protein kinase C (PKC) may require the on-contraction in response to EFS using feline esophageal smooth muscle. The contractions were recorded using an isometric force transducer. On-contraction occurred in the presence of NG-nitro-L-arginine methyl ester (L-NAME), suggesting that nitric oxide acts as an inhibitory mediator in smooth muscle. The excitatory composition of both contractions was cholinergic dependent which was blocked by tetrodotoxin or atropine. The on-contraction was abolished in Ca2+-free buffer but reappeared in normal Ca2+-containing buffer indicating that the contraction was Ca2+ dependent. 4-aminopyridine (4-AP), voltage-dependent K+ channel blocker, significantly enhanced on-contraction. Aluminum fluoride (a G-protein activator) increased on-contraction. Pertussis toxin (a Gi inactivator) and C3 exoenzyme (a rhoA inactivator) significantly decreased on-contraction suggesting that Gi or rhoA protein may be related with Ca2+ and K+ channel. ML-9, a MLCK inhibitor, significantly inhibited on-contraction, and chelerythrine (PKC inhibitor) affected on the contraction. These results suggest that endogenous cholinergic contractions activated directly by low-frequency EFS may be mediated by Ca2+, and G proteins, such as Gi and rhoA, which resulted in the activation of MLCK, and PKC to produce the contraction in feline distal esophageal smooth muscle.
4-Aminopyridine ; Aluminum ; Aluminum Compounds ; Atropine ; Azepines ; Benzophenanthridines ; Contracts ; Esophagus ; Fluorides ; GTP-Binding Proteins ; Muscle, Smooth ; Myosin-Light-Chain Kinase ; NG-Nitroarginine Methyl Ester ; Nitric Oxide ; Pertussis Toxin ; Protein Kinase C ; rhoA GTP-Binding Protein ; Tetrodotoxin ; Transducers