Wang Chunyou

Modulatory Effects of EPA and DHA on Proliferation and Apoptosis of Pancreatic Cancer Cells

In order to investigate the effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the proliferation, apoptosis of pancreatic cancer cell line SW1990 cells and the expression of cyclin E mRNA, the SW1990 cells were treated with different concentrations of EPA or DHA (20, 40, 60 μg/mL) for 0, 12, 24, 36 and 48 h respectively. By using MTT method, the inhibitory effects of EPA or DHA on the cell growth were assayed. Real time PCR was used to detect the expression changes of cyclin E mRNA after the SW1990 cells were treated with 40 μg/mL EPA or DHA for different time. Flow cytometry was used to test the changes of apoptostic rate in the SW1990 cells treated with different concentrations of EPA or DHA for 24 h. The results showed that EPA and DHA could inhibit the growth of SW1990 cells in a time-and concentration-dependent manner (P<0.01). EPA or DHA could also significantly inhibit the expression of cyclin E mRNA in a time-dependent manner (P<0.05). EPA or DHA could induce the apoptosis of SW1990 cells in a concentration-dependent manner (P<0.01). It was concluded that ω-3 fatty acid could inhibit the proliferation of pancreatic cancer cell line SW1990 cells and promote their apoptosis. The down-regulation of the cyclin E expression by ω-3 fatty acid might be one of the mechanisms for its anti-tumor effect on pancreatic cancer.

Expression of angiopoietin-2 gene and its receptor Tie2 in hepatocellular carcinoma.

SummaryTo explore the relationship of angiogenesis-related angiopoietin-2 gene and its receptor Tie2 with angiogenesis and the biology, of hepatocellular carcinoma (HOC), angiopoietin-2 gene, Tie2 and CD34 protein expression in 22 resected HOC, 8 cirrhotic and 8 control liver specimens were investigated byin situ hybridization and immunohistochemistry respectively, and the level of angiopoietin-2 and Tie2 expression in HCC were compared in terms of tumor biological parameters. It was found that CD34 was not expressed in control liver, expressed scarcely in cirrhotic liver (17. 8±13.5/HP), but intensively expressed in HCC (86. 3±34. 8/HP,P<0.01). Tie2 receptor was not expressed in controls, expressed at low level in cirrhotic liver (11. 3±8.7/HP), while strongly positive in the microvascular endothelia of HCC (52. 4±16. 7/HP,P<0.01). The level of Tie2 receptor expression in HCC was closely related with tumor diameter, angiogenesis and portal invasion. Angiopoietin-2 gene was not expressed in control liver, expressed mildly in cirrhotic liver (11.2±9. 7/HP), but extensively in tumor zone (36. 4±17. 5/HP), the level of angiopoietin-2 expression was closely related with angiogenesis, portal invasion and histological grading of HCC. It is concluded that angiogenesis is increased in HCC; angiopoietin-2/Tie2 expression in human hepatic carcinoma is closely related with angiogenesis, which are probably involved in the HCC angiogenesis regulation, promoting the development and metastasis of human hepatic cancer.

Diagnosis and management of severe acute pancreatitis complicated with abdominal compartment syndrome

SummaryPresented in this paper is our experience in the diagnosis and management of abdominal compartment syndrome during severe acute pancreatitis. On the basis of the history of severe acute pancreatitis, after effective fluid resuscitation, if patients developed renal, pulmonary and cardiac insufficiency after abdominal expansion and abdominal wall tension, ACS should be considered. Cystometry could be performed to confirm the diagnosis. Emergency decompressive celiotomy and temporary abdominal closure with a 3 liter sterile plastic bag must be performed. It is also critical to prevent reperfusion syndrome. In 23 cases of ACS, 18 cases received emergency decompressive celiotomy and 5 cases did not. In the former, 3 patients died (16.7%), while in the later, 4 (80%) died. Total mortality rate was 33.3% (7/21). In 7 death cases, 4 patients developed acute obstructive suppurative cholangitis (AOSC). All the patients who received emergency decompressive celiotomy 5 h after confirmation of ACS survived. The definitive abdominal closure took place mostly 3 to 5 days after emergency decompressive celiotomy, with longest time being 8 days. 6 cases of ACS at infection stage were all attributed to infected necrosis in abdominal cavity and retroperitoneum. ACS could occur in SIRS stage and infection stage during SAP, and has different pathophysiological basis. Early diagnosis, emergency decompressive celiotomy and temporary abdominal closure with a 3L sterile plastic bag are the keys to the management of the condition.

Correlation between protein expression of PTEN in human pancreatic cancer and the proliferation, infiltration, metastasis and prognosis

In order to investigate the correlation between protein expression of PTEN and the proliferation, infiltration, metastasis and prognosis in pancreatic cancer, immunohistochemical SP method was used to examine the protein expression of PTEN, PCNA, MVD, MMP-2, MMP-9 and TUNEL method to detect the levels of apoptosis of pancreatic cells in 41 pancreatic head cancers from regional pancreatectomy (RP) and 10 normal pancreatic tissues. The results showed that among 41 cases of pancreatic cancers, the positive staining of PTNE (39.02 %) was significantly weaker than that in normal pancreatic tissues (P<0.05). The levels of PCNA labeling index (LI), apoptotic index (AI), microvessel density (MVD), MMP-2 LI and MMP-9 LI were decreased gradually with the increase of the expression intensity of PTEN, and there was a significant difference in the above parameters among the patients having different expression levels of PTEN (P<0.01 or P<0.05). There was a negative correlation between the expression of PTEN and PCNA LI, MVD, MMP-2 LI, MMP-9 LI, and a positive correlation between AI and the expression of PTEN. The expression intensity of PTEN was correlated with the postoperative survival of the patients with pancreatic cancer (x 2 =22.3400, P<0.0001, RR=2.030). It was suggested that the expression levels of PTEN protein were closely related with proliferation, infiltration and metastasis in human pancreatic cancer, and the expression of PTEN protein was one of the prognostic factors for pancreatic cancer following RP.

PDX-1 expression in pancreatic ductal cells after partial pancreatectomy in adult rats

SummaryTo investigate the protein and mRNA expression of pancreas/duodenal homeobox-1 (PDX-1), a transcription factor as a marker for pancreatic stem cells, in pancreatic ductal cells of rats after partial (90%) pancreatectomy and evaluated the significance of the PDX-1 expression. Western blot and Reverse transcriptase-polymerase chain reaction (RT-PCR) were used to detect the expression of PDX-1 protein and mRNA respectively. PDX-1 protein was only faintly detected in pancreatic ductal cells on the day 1 after partial pancreatectomy. On the day 2 and 3 after operation in operation group, a 2–3 fold increased PDX-1 protein was observed, corresponding to the characteristic 42-kD protein in Western blot. There was significant difference between operation group and sham-operation group (P<0.05). PDX-1 protein expression on the day 5 and 7 after operation had already been no difference from control group (P>0.05). RT-PCR revealed the PDX-1 mRNA expression showed no significant difference between operation group at various time points and sham-operation group (P>0.05). These results indicate that there was overexpression of PDX-1 in the cells of pancreatic epithelium during the regeneration of remnant pancreas after partial pancreatectomy in adult rats, suggesting the pancreatic stem cells in pancreatic ductal epithelial cells are involved in the regeneration of remnant pancreas and the expression of PDX-1 in ductal cells was regulated posttranscription.

Experience in diagnosis and treatment of bleeding complications in severe acute pancreatitis by TAE

The experience in diagnosis and treatment of bleeding complications in severe acute pancreatitis (SAP) by transcatheter arterial embolization was summarized. The clinical data of 19 SAP patients complicated with intra-abdominal bleeding in our hospital from Jan. 2000 to Jan. 2003 were analyzed retrospectively and the therapeutic outcome of TAE was evaluated statistically. The results showed that the short-term successful rate of hemostasis by TAE was 89.5% (17/19), the incidence of re-bleeding after TAE was 36.8% (7/19) and the successful rate of hemostatis by second TAE was 71.4% (5/7). It was concluded that the intra-abdominal bleeding in SAP was mainly caused by the rupture of erosive/infected pseudoaneurysm. Mostly, the broken vessels were splenic artery and gastroduodenal artery; In terms of emergence hemostatis, TAE is the most effective method. Surgical hemostasis is necessary if hemostasis by TAE is failed or re-bleeding occurs after TAE.SummaryThe experience in diagnosis and treatment of bleeding complications in severe acute pancreatitis (SAP) by transcatheter arterial embolization was summarized. The clinical data of 19 SAP patients complicated with intra-abdominal bleeding in our hospital from Jan. 2000 to Jan. 2003 were analyzed retrospectively and the therapeutic outcome, of TAE was evaluated statistically. The results showed that the short-term successful rate of hemostasis by TAE was 89.5% (17/19), the incidence of re-bleeding after TAE was 36.8% (7/19) and the successful rate of hemostatis by second TAE was 71.4% (5/7). It was concluded that the intra-abdominal bleeding in SAP was mainly caused by the rupture of erosive/infected pseudoaneurysm. Mostly, the broken vessels were splenic artery and gastroduodenal artery. In terms of emergence hemostatis, TAE is the most effective method. Surgical hemostasis is necessary if hemostasis by TAE is failed or re-bleeding occurs after TAE.

Effect of early hemofiltration on pro- and anti-inflammatory responses and multiple organ failure in severe acute pancreatitis.

SummaryThe effects of early hemofiltration on the serum levels of cytokines, pro-and anti-inflammatory balance and organ function in pigs with severe acute pancreatits (SAP) were studied. SAP pig model was induced by retrograde injection of artificial bile into the pancreatic duct. The pigs were randomly divided into SAP hemofiltration treatment group (HF group,n=8) and SAP nonhemofiltration treatment group (NHF group,n=8). In the HF group, the animals were subjected to high-volume and zero-balance hemofiltration therapy. The results showed that as compared with NHF group, MAP, CVP and PaO2/FiO2 were significantly increased (P<0.01), while HR, urinary protein content, serum ALT level, pulmonary coefficient and lung wet/dry ratio obviously decreased (P<0.05) in HF group. Under a light microscope, the pulmonary histologic scoring was lower that in HF group (P<0.01) and the lesions of renal and liver tissues were milder. However, there was no significant difference in the pancreatic histologic scoring between the two groups. Six h after establishment of the model, the serum levels of TNF-α, IL-1β were lower, while the IL-10/TNF-α ratio was higher in HF group (allP<0.05). It was suggested that early hemofiltration could effectively remove the serum cytokines TNF-α and IL-1β in SAP pigs, elevate the ratio of IL-10/TNF-α, improve hemodynamics and alleviate the lesions of lung, kidney and liver tissues.

Preparation and preservation of hypoxia UW solution

In order to explore the method to prepare hypoxia UW solution and the stability and preservation of hypoxia UW solution, UW solution was purged by argon or air for 15 min or 60 at a flow rate of 0.8 or 2 L/min, and the oxygen partial pressure of UW solution was detected. The hypoxia UW solution was exposed to the air or sealed up to preserve by using different methods, and the changes of oxygen partial pressure was tested. The results showed that oxygen partial presure of 50 mL UW solution, purged by argon for 15 min at a flow rate of 2 L/min, was declined from 242±6 mmHg to 83±10 mmHg. After exposure to the air, oxygen partial pressure of hypoxia UW solution was gradually increased to 160±7 mmHg at 48 h. After sealed up by the centrifuge tube and plastic bad filled with argon, oxygen partial pressure of hypoxia UW solution was stable, about 88±13 mmHg at 72 h. It was concluded that oxygen of UW solution could be purged by argon efficiently. Sealed up by the centrifuge tube and plastic bag filled with argon, oxygen partial pressure of UW solution could be stabilized.

Construction and expression of human PTEN tumor suppressor gene recombinant adenovirus vector

SummaryThe recombinant defective adenovirus vector carrying human PTEN tumor suppressor gene was constructed by using AdEasy-1 system and its expression was detected in human breast cancer cell line MDA-MB-468. Human PTEN cDNA was cloned into adenovirus shuttle plasmid pAdTrack-CMV to generate a recombinant plasmid pAdTrack-CMV-PTEN, then homologeous recombination was carried out in the E. coli BJ5183 by contransforming linearized shuttle vector with adenovirus backbone plasmid pAdEasy-1. The newly recombined defective adenovirus vector Ad-PTEN containing green fluorescent protein (GFP) was packaged and propagated in 293 cells. After being purified by cesium chloride gradient centrifugation, the adenovirus was transfected into human breast cancer cell line MDA-MB-468 in vitro. The expression of PTEN mRNA and protein in infected human breast cancer cell line MDA-MB-468 was detected by RT-PCR and Western blot respectively. The recombinant defective adenovirus vector carrying PTEN gene was constructed successfully. The viral titer of purified adenovirus was 2.5×1010 pfu/mL, and about 70% breast cancer cells were infected with Ad-PTEN when multiplicity of infection (MOI) reached 50. The exogenous PTEN mRNA and protein were expressed in MDA-MB-468 cells infected with Ad-PTEN by RT-PCR and Western blot. The recombinant defective adenovirus vector of PTEN gene was constructed successfully using AdEasy-1 system rapidly, which paved a sound foundation for gene study of breast cancer.

INHIBITION OF ACTIVATED K-RAS GENE BY SIRNA EXPRESSION CASSETTES IN HUMAN PANCREATIC CARCINOMA CELL LINE MIAPACA-2

Objective: To construct the small interfering RNA(siRNA) expression cassettes (SECs) targeting activated K-ras gene sequence and investigate the effects of SECs on K-ras gene in human pancreatic cancer cell line MIAPaCa-2. Methods: Three different sites of SECs were constructed by PCR. The K1/siRNA, K2/siRNA and K3/siRNA were located at the site 194, 491 and 327, respectively. They were transfected into MiaPaCa-2 cells by liposome to inhibit the expression of activated K-ras. In the interfering groups of site 194, 491, we observed the cytopathic effect of confluent MiaPaCa-2 cells after they were incubated for 48 hours, and detected the apoptosis in cells by FACS, then we tested the alternation of K-ras gene in confluent MiaPaCa-2 cells by RT-PCR, immunofluorescence and western blot, respectively. Results: Introductions of the K1/siRNA and K2/siRNA against K-ras into MiaPaCa-2 cells led to cytopathic effect, slower proliferation and increased apoptosis, while the appearances of control MiaPaCa-2 cells remained well. The number of apoptotic cells increased compared with control cells. RT-PCR, immunofluorescence and western blot showed the effects of inhibited expression of activated K-ras gene by RNA interference in the K1/siRNA and K2/siRNA groups. We also found that the introduction of K3/siRNA had no effect on MiaPaCa-2 cells. Conclusion: K1/siRNA and K2/siRNA can inhibit the expression of activated K-ras and decrease the growth of MiaPaCa-2 cells, while K3/siRNA has no such effect, demonstrating that the suppression of tumor growth by siRNA is sequence-specific. We conclude that K-ras is involved in maintenance of tumor growth of human pancreatic cancer, and SECs against K-ras expression may be a powerful tool to be used therapeutically against human pancreatic cancer.