and laminin on adhesion and proliferation of human hepatocellular carcinoma cell

AIM:To explore the effects of PMA(phorbol-12-myristate-13-acetate, a tumor promoter, mimicking the action of diacylglycerol on PKC)and laminin on the adhesion and the proliferation of human hepatocellular carcinoma cells, and provide a new clue to liver cancer treatment.METHODS:Human hepatocellular carcinoma cell line(BEL-7402)was used to identify the endogenous laminin and protein kinase C-α(PKC-α) expression, and the effects of laminin and PMA on the adhesion and the proliferation were also investigatedin vitro.RESULTS:By the effect of exogenous laminin, human hepatocellular carcinoma cell (BEL-7402) possessed endogenous laminin expression and increased the adhesion and the proliferation, which was showed the synergistic action by the effect of PMA in combination. By the action of PMA alone, the proliferation and the PKC-α expression increased by exogenous laminin were decreased, and the adhesion and the endogenous laminin expression were increased.CONCLUSIONS:The finding suggested that the adhesion and the proliferation of human hepatocellular carcinoma cell were closely related to the effects of endogenous or exogenous laminin, which were associated with cPKC-α activity. Therefore, the application of anti-laminin antibody in combination with PKC antagonist might be a new clue to find out the therapy for liver cancer.     

Study on integrin-mediated albumin microbubbles adherence to activated leukocytes

AIM:To investigate the mechanism responsible for albumin microbubbles adherence to activated leukocytes. METHODS: In vitro studies were performed in which activated or nonactivated leukocytes were incubated with albumin microbubbles and observed under microscopy. The suspensions of leukocytes and microbubbles which contained or absented of integrins were analyzed with flow cytometry.RESULTS: A minimum of 50cells were identified under transillumination. 5 min after microbubbles were incubated with leukocytes, the number of cells interacting with microbubbles was greater for activated cells than for nonactivated cells(20.30±2.67 vs 4.50±1.43, P <0.01).Microbubbles attached to the surface of activated leukocytes were phagocytosed and remained intact for up to 30min. Microbubble attachment was inhibited notably by blocking the leukocyte β₂-integrin Mac-1(P <0.01) and by VLA-4mAb slightly(P <0.05) CONCLUSION: The mechanism of albumin microbubbles attaching to and phagocytosed by leukocytes was due to β₂-integrin and VLA-4 mediation. Phagocytosed microbubbles can remain at the regions of inflammation for15 min, also responsible to ultrasound.     

Progresses on antitumor effect of snake venom active components

Many snake venoms contain complex mixtures of pharmacologically important molecules, some of which show potential therapeutic value in the treatment of cancer and other human disorders. In this review, we mainly reports the effects of snake venom active components, such as disintegrins and lectins in paralyzing cancer cells, blocking on cell migration, interaction with integrins, inhibition of tumor dissemination and angiogenesis. The advanced researches on the snake venom's apoptosis-inducing components on tumors are also introduced.     

Effects of rat tail collagen and C-erbB-2 antibody on the adhesion and proliferation in hepatocellular carcinoma cells

AIM: To explore the effect of collagen and C-erbB-2 protein on the adhesion and the proliferation in hepatocellular carcinoma cells. METHODS: Hepatocellular carcinoma cell line (HepG-2) identified to positive for C-erbB-2 gene was used to study the adhesion and the growth feature by the action of rat tail collagen and C-erbB-2 antibody.RESULTS: The action of rat tail collagen to potentiated the adhesion in HepG-2 cells was significantly but no proliferation effect was observed. C-erbB-2 antibody inhibited the adhesion and proliferation of HepG-2 cells and also abolished the potentiated effect of rat tail collagen on the adhesion in HepG- 2 cells. CONCLUSION: The signaling transduction mediated by C-erbB-2 protein was correlated to the adhesion and the proliferation of HepG-2. The blockage of C-erbB-2 gene signal transduction may be a strategic target to the treatment of liver cancer in the future.     

Effect of mininally modified low density lipoprotein on the adhesive function of vascular endothelial cell and its mechanism

AIM: To observe the effect of MM-LDL (minimally modified LDL) on the interaction between human umbilical vein endothelial cell (HUVEC) and U937 monocyte-like cell line and the exporession of vascular cell adhesion-1 (VCAM-1), intercellular adhesion molecule-1(ICAM-1), P-selectin.METHODS:The adhesive percentage between HUVEC treated with MM-LDL and U937 was determined by counting and the expression of VCAM-1, ICAM-1, P-selectin were examined by ELISA. RESULTS: Treatment of HUVEC with MM-LDL (75 mg/L) for 4 hours significantly increased adhesion of U937 to HUVEC ( P <0.01) and did not induce the surface expression of VCAM-1, ICAM-1, P-selectin . Recombination tumor necrosis factor-alpha (rTNF_α) 5.0 μg/L, as a positive control, induced the expression of these adhesion molecules ( P <0.05). Prolonged (18 h) exposure to MM-LDL resulted in the expression of P-selectin, but not VCAM-1.CONCLUSION: the adhesion of monocytes to endothelial cells induced by MM-LDL is not mediated by VCAM-1, ICAM-1. P-selectin induction may be partly involved in the process.     

Fibrinolytic Responses of the Equine Peritoneum to Abdominal Surgery,Surgical Trauma,and Intraperitoneal Sodium Hyaluronate

Postoperative abdominal adhesions are known to present clinical challenges to the surgeon. Adhesion formation is a balance modulated by the fibrinolytic system. The key components involved are the tissue plasminogen activators (tPAs) and plasminogen activator inhibitors (PAI-1 and PAI-2). Sodium hyaluronate (HA) has been shown to reduce the incidence and severity of adhesions in horses. The objectives of this study were to measure tPA and PAI-1 activity in equine peritoneum and evaluate the effect of 0.4% HA solution on local tPA and PAI-1 activity. An exploratory laparotomy was performed and local serosal trauma was induced by using an established abrasion model. Our study involved two groups: in the first group (n = 6) 0.4% HA was used in all intestinal manipulations, whereas in the second group (n = 6) sterile saline was used. Parietal peritoneum, jejunal seromuscular biopsies at abraded sites (AJ) and nonabraded sites, and peritoneal fluid samples were taken at time 0- and at 30-minute intervals up to 120 minutes. Peritoneum tPA activity was significantly decreased at 60 and 90 minutes. Interestingly, AJ contained significantly higher tPA activity than nonabraded sites at 30-, 60-, 90-, and 120-minute intervals in control horses. The increase in tPA activity with AJ in treated (HA) horses was significantly attenuated as compared with the control (saline). Detectable levels of PAI-1 activity could not be identified in our samples. The results of our study indicate that exploratory celiotomy in horses is associated with a significant decrease in peritoneal tPA activity, and HA significantly decreases the fibrinolytic response of the jejunum to surgical trauma. Further characterization of these responses will hopefully lead to new pharmacologic strategies for adhesion prevention.