Syk Kinase ; Tyrosine/metabolism* ; Phosphorylation

Abstract　　Spleen tyrosine kinase (SYK) is not only a key kinase in the B-cell receptor (BCR) signaling pathway, but also a critical component of other signal transduction pathways such as Fc receptor, complement receptor and integrin. Abnormal activation of SYK closely related to the occurrence and development of hematological malignancies, thus targeting SYK has become a research hotspot. Several SYK inhibitors including Fostamatinib, Entospletinib and Cerdulatinib were being evaluated in clincal trials. As a second generation SYK inhibitor, Entospletinib has achieved good efficacy in lymphoid and myeloid hematologic tumors. Furthermore, Entospletinib can significantly relieve hematopoietic stem cell transplantation(HCT) related graft versus host disease (GVHD). In this review the role of SYK inhibitors in treatment of hematological malignancies is summarized brifely.
Graft vs Host Disease ; Hematologic Neoplasms ; Humans ; Protein Kinase Inhibitors ; Spleen ; Syk Kinase

The present paper was aimed to study the role of spleen tyrosine kinase (Syk) in angiogenesis in hepatopulmonary syndrome (HPS) and the underlying mechanism. Sprague Dawley (SD) rats were randomly divided into three groups: sham operation group (sham group), common bile duct ligation (CBDL) 5-week group (5W group) and R788 intervention group (R788 group). HPS model was established by CBDL. Rats in R788 group were intraperitoneally injected with R788 (20 mg/kg) once daily to week 5 after CBDL operation. The protein expression levels and distribution of Syk, p-Erk1/2, and p-Akt in lung tissue were detected by Western blot and immunohistochemistry. Immunofluorescence staining was used to observe the location of Syk expression and the number of angiogenesis in lung tissue. The results showed that, compared with sham group, 5W group exhibited up-regulated protein expression level of Syk, increased phosphorylation levels of Erk1/2 and Akt, and increased number of pulmonary microvessels. Compared with 5W group, R788 group exhibited down-regulated protein expression level of Syk, decreased phosphorylation levels of Erk1/2 and Akt, and decreased number of pulmonary microvessels. These results suggest that Syk may promote pulmonary angiogenesis in HPS model rats by activating downstream Erk1/2 and Akt signaling pathways, which provides a theoretical basis and potential drug therapeutic targets for the clinical treatment of HPS.
Animals ; Disease Models, Animal ; Hepatopulmonary Syndrome ; Lung ; Rats ; Rats, Sprague-Dawley ; Syk Kinase

OBJECTIVETo investigate the expression of full-length spleen tyrosine kinase [SYK (L)] mRNA and protein in human oral squamous cell carcinoma (OSCC) as well as its possible effects on the invasion and metastasis of OSCC.

METHODSThe expression of SYK (L) was detected in 27 cases of OSCC tissues and its matched adjacent non-cancerous tissues by real-time quantitative polymerase chain reaction (RT-qPCR), Western blot, and immunohistochemistry. Fourteen cases of normal oral gingival tissues were also analyzed as a normal control.

RESULTSReduced mRNA and protein expression of SYK (L) in OSCC tissues was observed compared with that in normal oral gingival tissues (P<0.01) and adjacent non-cancerous tissues (P<0.05). SYK(L) expression was significantly associated with lymph-node metastasis (P<0.05).

CONCLUSIONSYK(L) is a candidate tumor suppressor for OSCC tissues, and has an inhibitive effect on the initiation, proliferation, and lymph-node metastasis of human OSCC.

Blotting, Western ; Carcinoma, Squamous Cell ; metabolism ; Humans ; Immunohistochemistry ; Lymphatic Metastasis ; Mouth Neoplasms ; metabolism ; RNA, Messenger ; Syk Kinase ; metabolism

P-selectin engagement of P-selectin glycoprotein ligand-1 (PSGL-1) causes circulating leukocytes to roll on and adhere to the vascular surface, and mediates intracellular calcium flux, a key but unclear event for subsequent arresting firmly at and migrating into the infection or injured tissue. Using a parallel plate flow chamber technique and intracellular calcium ion detector (Fluo-4 AM), the intracellular calcium flux of firmly adhered neutrophils on immobilized P-selectin in the absence of chemokines at various wall shear stresses was investigated here in real time by fluorescence microscopy. The results demonstrated that P-selectin engagement of PSGL-1 induced the intracellular calcium flux of firmly adhered neutrophils in flow, increasing P-selectin concentration enhanced cellular calcium signaling, and, force triggered, enhanced and quickened the cytoplasmic calcium bursting of neutrophils on immobilized P-selectin. This P-selectin-induced calcium signaling should come from intracellular calcium release rather than extracellular calcium influx, and be along the mechano-chemical signal pathway involving the cytoskeleton, moesin and Spleen tyrosine kinase (Syk). These results provide a novel insight into the mechano-chemical regulation mechanism for P-selectin-induced calcium signaling of neutrophils in flow.
Calcium Signaling ; Female ; Humans ; Male ; Membrane Glycoproteins ; metabolism ; Neutrophils ; metabolism ; P-Selectin ; metabolism ; Stress, Mechanical ; Syk Kinase ; metabolism

OBJECTIVEThis study explores the mechanism of cyclooxygenase-2 (COX-2) upregulation in oral cancers associated with macrophage by using molecular biology techniques and primary culture of murine macrophage.

METHODSMurine macrophage was induced by macrophage colony-stimulating factor (M-CSF) and Cal27 conditional medium (CM). Purity of the macrophage was detected through CD68 immunofluorescence staining. Inhibitors of spleen tyrosine kinase (Syk) and nuclear factor κB (NFκB) were used to inhibit these pathways. In addition, real-time polymerase chain reaction and Western blot analysis were used to detect alterations in COX-2 and pathway-related proteins.

RESULTSAll of the induced cells specifically expressed CD68. Cal27 CM could significantly induce COX-2 expression (P<0.001). Moreover, inhibition of Syk pathway attenuated NFκB-P65 phosphorylation and reduced COX-2 expression (P<0.01), and inhibition of NFκB pathway exerted no effects on Syk phosphorylation but significantly inhibited COX-2 upregulation (P<0.01).

CONCLUSIONSSyk-NFκB is responsible for COX-2 overexpression in oral cancer associated with macrophages. Targeting this pathway is possibly a new approach to control oral cancer-related pain.
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Animals ; Cancer Pain ; Cyclooxygenase 2 ; Macrophage Colony-Stimulating Factor ; Macrophages ; Mice ; Mouth Neoplasms ; NF-kappa B ; Phosphorylation ; Signal Transduction ; Spleen ; Syk Kinase ; Up-Regulation

OBJECTIVE: To observe the effect of electroacupuncture (EA) preconditioning on the expressions of tyrosine kinase Lyn and spleen tyrosine kinase (Syk) in mast cells of subcutaneous loose connective tissue in the rats with urticaria and explore the potential biological mechanism of EA in the intervention of urticaria. METHODS: A total of 32 SD rats were randomized into a blank group, a model group, an EA group and a positive medication group, 8 rats in each one. Except of the blank group, the passive cutaneous anaphylaxis (PCA) was adopted to prepare the model of urticaria in the rats of the rest three groups. In the EA group, EA was applied to bilateral "Quchi" (LI 11), "Xuehai" (SP 10) and "Zusanli" (ST 36), with disperse-dense wave, 2 Hz/15 Hz in frequency and 1 mA in current intensity, once daily, for 20 min each time, consecutively for 7 days. In the positive medication group, loratadine (1 mg•kg•d) was for intragastric administration, once daily, consecutively for 7 days. The samples were collected for index detection 30 min after PCA antigen challenge in the rats of each group. Spectrophotometer was adopted to determine the effusion quantity of Evans blue in the allergized site of skin. HE staining was used to observe the morphological changes in the allergized site of skin. Toluidine blue staining was provided to observe mast cell degranulation in subcutaneous loose connective tissue in the allergized site of skin. Immunohistochemistry was applied to determine the protein expressions of Lyn and Syk during degranulation of mast cells. RESULTS: In the rats of the odel group, the eipdermis of allergized site was thickening, cells were disorganized in hierarchy and inflammatory cells were infiltrated largely in the dermis. In the positive medication group and the EA group, the epidermis was getting thin, cell arrangement was clear and the inflammatory cell infiltration was obviously alleviated as compared with the model group. Compared with the blank group, the OD value of skin dye effusion quantity, the degranulation rate of mast cells and the positive expressions of Lyn and Syk were all increased in the model group (<0.01). Compared with the model group, the OD value of skin dye effusion quantity, the degranulation rate of mast cells and the positive expressions of Lyn and Syk were all reduced in the EA group and the positive medication group (<0.01). Compared with the positive medication group, the degranulation rate of mast cells was increased significantly in the EA group (<0.01). CONCLUSION Electroacupuncture at "Quchi" (LI 11), "Xuehai" (SP 10) and "Zusanli" (ST 36) reduces vascular permeability and gives play to the role of anti-allergy by the way of regulating and controlling the degranulation of mast cells in the rats with urticaria and the effect mechanism of electroacupuncture may be related to the inhibition of protein expressions of Lyn and Syk in mast cells.
Acupuncture Points ; Animals ; Connective Tissue ; metabolism ; Electroacupuncture ; Mast Cells ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Syk Kinase ; metabolism ; Urticaria ; therapy ; src-Family Kinases ; metabolism

OBJECTIVES: To study the antitumor effect of piceatannol (PIC) on malignant melanoma METHODS: B16F10 cells were cultured RESULTS: The cell viability of B16F10 decreased with increasing PIC concentration. The results of the Transwell assay showed that invasion ability decreased with increasing PIC concentration, and healing time was prolonged at increased PIC concentration in the wound healing assay. Western blot results showed that PIC mainly inhibited the phosphorylation of Syk and inhibited the expression of MMP-2, MMP-9, and VEGF. RNA interference pointed out that blocking the expression of Syk can reveal the same inhibition effect on B16F10 cells as PIC. CONCLUSIONS PIC might block the progression of malignant melanoma by inhibiting spleen tyrosine kinase.
Animals ; Cell Line, Tumor ; Cell Movement ; Matrix Metalloproteinase 2 ; Matrix Metalloproteinase 9 ; Melanoma/drug therapy* ; Mice ; Neoplasm Invasiveness ; Stilbenes/pharmacology* ; Syk Kinase ; Vascular Endothelial Growth Factor A

Platelet is activated through signal transduction, that mainly includes phospholipase-beta (PLCbeta) pathway, protein tyrosine kinases (PTK) pathway, phosphatidylinositol3-kinase (PI3-K) pathway, mitogen-activated protein kinases (MAPK) pathway, cyclic adenosine monophosphate-protein kinase A (cAMP-PKA) pathway and phospholipase A2 (PLA2) pathway. This article focuses on the relationship between signal transduction and platelet activation.
Calcium ; metabolism ; Enzyme Precursors ; metabolism ; Guanosine Triphosphate ; metabolism ; Humans ; Intracellular Signaling Peptides and Proteins ; Phosphatidylinositol 3-Kinases ; physiology ; Platelet Activation ; Protein-Tyrosine Kinases ; metabolism ; Signal Transduction ; Syk Kinase ; von Willebrand Factor ; physiology

OBJECTIVETo investigate the role of spleen tyrosine kinase (syk) in the phenotypic modulation induced by platelet-derived growth factor (PDGF-BB) in rat pulmonary vascular smooth muscle cells (VSMC).

METHODSVascular smooth muscles were isolated from pulmonary media of SD rats, cultured, adopted, and divided into 3 groups: blank control group, control group and medicine intervention group. The changes of proliferation and ultrastructure of vascular smooth muscle cells by using [(3)H] thymidine incorporation and electron microscopy. The mRNA and protein expression level of syk, alpha-smooth muscle-actin (α-SM-actin) and smooth muscle protein 22alpha (SM22α) were detected by RT-PCR and Western blotting. The change of fluorescence intensity was detected by laser scanning confocal microscope.

RESULTSTreatment with PDGF-BB for 24 h resulted in a significant increase in [(3)H] thymidine incorporation (2429.25 ± 253.36 vs. 242.75 ± 14.33,P < 0.01) and marked change in phenotype and cytoskeleton, the level of average optical density decreased significantly (263.75 ± 19.21 vs.1146.23 ± 62.61, P < 0.01). Meanwhile, the mRNA (1.70 ± 0.25 vs. 1.01 ± 0.12, P < 0.05) and protein level of syk significantly increased, the mRNA and protein expression of α-SM-actin (0.10 ± 0.00 vs. 1.00 ± 0.00, P < 0.01) and SM22α (0.18 ± 0.00 vs. 1.00 ± 0.01, P < 0.01) significantly decreased in VSMC induced by PDGF-BB. Piceatannol could inhibit significantly these biological effects. Compared with control group, the level of [(3)H] thymidine incorporation (527.00 ± 27.76 vs. 2429.25 ± 253.36,P < 0.01) was significantly down-regulated and the VSMC presented an apoptotic status in medicine intervention group, the level of average optical density increased significantly (810.65 ± 37.94 vs. 263.75 ± 19.21,P < 0.01) in medicine intervention group. Meanwhile, the mRNA (0.36 ± 0.07 vs. 1.70 ± 0.25, P < 0.01) and protein level of syk significantly decreased. The mRNA and protein levels of α-SM-actin (0.22 ± 0.00 vs. 0.10 ± 0.00, P < 0.01) and SM22α (0.31 ± 0.00 vs. 0.18 ± 0.00, P < 0.01) were significantly higher in medicine intervention group than in control group. The level of average optical density increased significantly (810.65 ± 37.94 vs. 263.75 ± 19.21, P < 0.01).

CONCLUSIONSyk plays an important role in vascular remodeling by changing the phenotypes and cytoskeleton of VSMC stimulated by PDGF-BB.

Animals ; Cells, Cultured ; Intracellular Signaling Peptides and Proteins ; genetics ; Male ; Muscle, Smooth, Vascular ; cytology ; metabolism ; Myocytes, Smooth Muscle ; metabolism ; Phenotype ; Platelet-Derived Growth Factor ; genetics ; Protein-Tyrosine Kinases ; genetics ; Proto-Oncogene Proteins c-sis ; Rats ; Rats, Sprague-Dawley ; Syk Kinase