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Objective: To establish the human colorectal cancer cell model SW620/PAR4D with inducible suppression of proteinase activated receptor 4 (PAR4) expression, and investigate the role PAR4 plays in the proliferation and migration of cancer cells., Methods: A human colorectal cancer cell line with tetracycline-inducible expression regulatory system, namely SW620/Tet-on, was established; inducible expression lentiviral vector with artificial microRNA targeting PAR4, pLVX-Tight-Puro-PAR4-miR, was constructed and transfected into SW620/Tet-on to make an inducible PAR4-suppressed cell model SW620/PAR4D. Western blotting was used to confirm the suppression of PAR4 expression after the doxycycline (DOX) treatment. CCK-8 assay was used to evaluate the impact of suppressed PAR4 expression on cell proliferation, and wound-healing assay was used to analyze the migration of the cells., Results: The SW620/PAR4D cell model was established successfully. Suppression of PAR4 expression by DOX treatment had no significant impact on the growth/proliferation of SW620/PAR4D cells, but markedly inhibited the cell migration., Conclusion: Suppression of PAR4 expression has no significant effect on the proliferation of SW620 cells, but can inhibit the migration of the cells.

Aim: To construct artificial microRNA expression vector targeting PAR4 and suppress the expression of PAR4 in human colorectal cancer SW620 cells with the artificial microRNA., Methods: Artificial microRNA was designed and amplified by two rounds of PCR and cloned into pMD-19T vector. The sequence of the cloned artificial microRNA was verified by DNA sequencing. Eight tandemly-repeated artificial microRNAs were subcloned into mammalian expression vector pcDNA3.1(+) to make the artificial microRNA- expressing vector pcDNA3.1(+)-8xPAR4-microRNA. The vector was transfected into human colorectal cancer SW620 cells, and stable transfectants were selected by G418. The expression of PAR4 was examined by Western blot., Results: DNA sequencing showed that the sequence of the cloned artificial microRNA targeting PAR4 was correct. Western blot result showed that the expression of PAR4 in SW620 cells stably transfected with pcDNA3.1(+)-8xPAR4-microRNA was markedly downregulated when compared to SW620 parental cells., Conclusion: Artificial microRNA expression vector targeting PAR4 is successfully constructed with significant suppression effect on PAR4 expression in SW620 cells. This provides the basis for future studies on the function of PAR4 and potential cancer gene therapy targeting PAR4.

Objective: To observe the effect of Xiaoyu Zhixue Tablet (XYZXT) on expression of platelet membrane glycoproteins (GP) Ib/IX/V complex and its component GP Ibalpha in patients with hemorrhagic thrombopathy, so as to explore its possible mechanism., Methods: Ninety-eight patients with hemorrhagic thrombopathy were randomly assigned to two groups, the TCM group (68 cases) treated with XYZXT and the Western medicine group (30 cases) treated with adrenosin, vitamins C, K and P, for 6 months totally. The hemostatic effect and the platelet aggregation recovery rate in the two groups were observed. And expressions of GPIb/IX/V complex and GP Ibalpha were analyzed by flow cytometry in both groups before and after treatment as well as in 34 healthy persons for control., Results: The hemostatic effective rate was 89.7% in the TCM group and 46.7% in the Western medicine group (u= 5.68, P < 0.01); the platelet aggregation recovery rate in the two groups was 67.6% and 3.3% respectively (chi2 = 34. 49, P < 0.01). The fluorescence intensity of GPIb/IX/V complex and GPIbalpha were lower in both groups before treatment than those of the healthy control (P < 0.05), but after treatment the two markers elevated in the TCM group, approaching the control (P > 0.05), and significantly higher than those in the Western medicine group (P < 0.05)., Conclusion: The partial mechanism of XYZXT in treating hemorrhagic thrombopathy might be its regulation on the expression of thrombin receptor at the receptor protein level.

Objective: To investigate the effects of puerarin on the proliferation of vascular smooth muscle cells (VSMC) induced by thrombin and the mechanism thereof., Methods: VSMCs were isolated from the thoracic aorta of a SD rat and cultured, then co-cultured with thrombin of the concentration 0.1, 0.3, 1.0, 3.0, and 10 U/L for 24 h, thrombin of the concentration of 1 U/L for 0, 6, 12, 24, 36, and 48 h respectively, or thrombin of the concentration of 1 U/L combined with puerarin of the concentrations of 1.5 x 10(-5), 1.5 x 10(-4), or 1.5 x 10(-3) mol/L for 24 h. Flow cytometry was used to detect the cell number and cell cycle. Western blotting was used to indicate the protein expression of the oncogenes c-fos and bcl-2 RT-PCR was used to evaluate the thrombin receptor (TR) mRNA expression., Results: he numbers of the groups of VSMCs stimulated by 0.1, 0.3, 1.0, 3.0, and 10 U/L thrombin for 24 hours were 4.82 x 10(4)/ml +/- 0.11 x 10(4)/ml, 6.37 x 10(4)/ml +/- 0.09 x 10(4)/ml, 8.78 x 10(4)/ml +/- 0.08 x 10(4)/ml, 7.37 x 10(4)/ml +/- 0.07 x 10(4)/ml, and 5.28 x 10(4)/ml +/- 0.12 x 10(4)/ml respectively, all significantly higher than that of the control group (4.08 +/- 0.054 x 10(4)/ml, all P < 0.05). The effect of thrombin was in a dose-dependent manner within a concentration range of 0.1 - 1.0 U/L. The suppression rates of VSMC proliferation in the combination groups with puerarin of the concentrations of 1.5 x 10(-5), 1.5 x 10(-4), and 1.5 x 10(-3) mol/L were 10.9% +/- 1.6%, 32.1% +/- 3.3%, and 42.6% +/- 5.2% respectively in comparison with the thrombin group (all P < 0.05). The c-fos protein expression of the VSMCs after thrombin stimulation for 24 h increased by 156.0% +/- 11.3% (P < 0.05), and the bcl-2 protein expression of the VSMCs pretreated with puerarin of the concentrations of 1.5 x 10(-5), 1.5 x 10(-4), and 1.5 x 10(-3) mol/L, and then stimulated by thrombin was significantly lower than that of the VSMCs only stimulated by thrombin with the suppression rates of 20.7% +/- 2.1%, 31.6% +/- 5.2%, and 44.5% +/- 7.5% respectively (all P < 0.05). The bcl-2 protein expression of the VSMCs after thrombin stimulation for 24 h increased by 96.7% +/- 8.3% (P < 0.05), and the bcl-2 protein expression of the VSMCs pretreated with puerarin of the concentrations of 1.5 x 10(-5), 1.5 x 10(-4), and 1.5 x 10(-3) mol/L, and then stimulated by thrombin was significantly lower than that of the VSMCs only stimulated by thrombin with the suppression rates of 7.1% +/- 0.8%, 18.8% +/- 1.2%, and 39.6% +/- 6.4% respectively (all P < 0.05). The stimulation of thrombin increased the TR mRNA expression by 183.9% +/- 9.4%. The puerarin of the concentrations of 1.5 x 10(-5) mol/L and 1.5 x 10(-4) mol/L decreased the increase of TR mRNA expression induced by thrombin, however, without significant differences (both P > 0.05), and puerarin of the concentration of 1.5 x 10(-3) mol/L significantly suppressed the increase of TR mRNA expression induced by thrombin by 17.6% +/- 1.7% (P < 0.05)., Conclusion: Puerarin suppresses the proliferation and DNA synthesis of VSMC induced by thrombin. The inhibitory effect of puerarin is closely related with the suppression of the protein expression of c-fos and bcl-2n, and partly related with the suppression of the TR mRNA expression.

Objective: To focus on the study of the effect on proliferation and apoptosis of human aortic smooth muscle cells (ASMC) by adeno-associated virus (AAV) vector carrying antisense thrombin receptor (ATR) and p21 double gene co-expression system., Methods: Cultured human AMSC was infected with recombinant AAV containing ATR, p21 single gene and AP double gene respectively. The integration and expression of genes were confirmed by semi-quantitative RT-PCR. The anti-proliferation effect was determined by MTT assay. Cell cycle and apoptotic cell counts were measured through Flow Cytometry. The rate of apoptotic cells was examined with acridine orange/ethidium bromide(AO/EB) stain., Results: RT-PCR indicated that the exogenous genes had been integrated into ASMC. The rates of cell survival were decreased by 16.67%, 21.60%, and 29.4% and the cell counts of G0/G1 phase were (61.8 +/- 2.9)%, (82.5 +/- 4.0)%, (80.4 +/- 6.1)% in ATR, p21 and AP group respectively after rAAV infected 4 days. The level and area of apoptotic peak were greater in AP double gene than ATR and p21 single gene. Cell stain indicated that apoptotic cells were (7.2 +/- 3.3)%, (10.7 +/- 5.6)%, and (18.3 +/- 2.7)% in each transgene group compared with (1.5 +/- 0.8)% in control group., Conclusion: AP double gene co-expression system has powerful effect for inhibiting proliferation and inducing apoptosis ASMC than ATR and p21 single gene and that is a superior way for gene therapy to restenosis.

Objective: To search for an effective approach to prevent the formation of restenosis after angioplasty., Methods: A recombinant eukaryotic expression plasmid vector containing partial antisense thrombin receptor (ATR) gene named pcDNA3/ATR was constructed using recombinant DNA technique. Mini-pig aorta injury model was established by over-sized balloon catheter combined with high cholesterol diet feeding and its aortic smooth muscle cells(ASMC) were cultured. The effect of ATR gene expression in mini pig ASMC proliferation and growth factor gene expression were studied by 3H-TdR incorporation and Northern blot., Results: The DNA synthesis in pig ASMC could be inhibited by ATR gene expression (The DNA synthesis in normal ASMC was lowered by 41.8%, and that in ASMC from injured artery was lowered by (50.3%). The mRNA and protein synthesis of TR could be down regulated by ATR gene expression. The mRNA expression of PDGF-A chain and bFGF stimulated by fetal calf serum (FCS) with thrombin were both downregulated in pig ASMC with expressed ATR gene., Conclusion: ATR gene expression can inhibit the proliferation of pig ASMC, and this is induced by its inhibiting effect on TR and finaly the signal transduction in ASMC.