胰腺癌相关基因寡核苷酸芯片的制备和初步应用(英文)

目的:研究胰腺癌相关基因寡核苷酸芯片的构建及其在检测胰腺癌基因表达谱方面的应用。方法:有目的地筛选胰腺癌相关基因,采用合成后点样的方法将合成的寡核苷酸探针点于同型双功能偶联剂(APS-PDC)包被的基片上,制成寡核苷酸基因芯片。Trizol法抽提组织总RNA,并用Qiagen Rneasy kit进一步纯化。在cDNA第1链合成过程中,通过反转录酶将CyDye标记核苷酸直接渗入到cDNA中制备荧光探针,其中用Cy3-dCTP标记胰腺癌组织,Cy5-dCTP标记正常胰腺组织。将荧光标记探针定量后与芯片杂交16-18 h。用Agilent扫描仪进行扫描,Imagene3.0软件(Biodiscovery,Inc.)图像分析,计算2种荧光Cy3与Cy5信号强度的比值。挑选差异基因CDC25B和TUSC3进行荧光定量PUR(Sybrgreen方法)验证,以B-actin基因为内参照基因,PCR产物的定量方法采用比较Ct法。结果:芯片杂交扫描图像信号清晰,具有较低的整体背景和较高的信噪比,各阳性质控点信号均匀一致,阴性质控点和空白点信号低。与正常组织相比,胰腺癌组织中差异表达基因24条,占全部基因的25.5%,其中上调基因17条(占18.1%),下调基因7条(占7.4%)。荧光定量PCR验证,CDC25B和TUSC3基因在胰腺癌中的表达分别为上调和下调,其表达趋势与芯片实验的结果一致。结论:制备的胰腺癌相关基因芯片,可同时、并行检测多种胰腺癌相关基因的表达改变,具有一定的特异性和灵敏性。胰腺癌组织与正常胰腺组织相比,基因表达谱具有明显的差异,为进一步研究胰腺癌的发病机理和早期诊断提供了有用的信息。

胰腺导管内乳头状黏液性肿瘤与胰腺导管腺癌的差异分析

目的 探讨胰腺导管内乳头状黏液性肿瘤（IPMN）与胰腺导管腺癌的差异.方法 回顾性收集2003年3月至2006年6月收治的资料完整的29例IPMN病例和46例胰腺导管腺癌的临床、生化、病理和随访资料,利用单因素及生存分析方法探讨两者的差异.结果 IPMN中无症状就诊比例明显高于胰腺导管腺癌（P＜0.05）.29例IPMN中21例为恶性,其病理分期明显早于胰腺导管腺癌（P=0.017）;肿瘤对胰腺内神经的侵犯较胰腺癌少见（P=0.005）.IPMN 患者术后的生存时间长于胰腺导管腺癌,而ⅡB期及以上的恶性IPMN患者术后生存时间与胰腺导管腺癌比较无明显差异.结论 IPMN与胰腺导管腺癌相比更易被早期诊断,其预后明显好于胰腺导管腺癌.尽管病理分期在ⅡB期及以上的恶性IPMN预后类似于胰腺导管腺癌,但仍有待进一步证实.

胰管支架治疗伴有胰管扩张的中晚期胰腺癌疼痛的临床对照研究

目的探讨胰管内引流术缓解伴有胰管扩张的中晚期胰腺癌患者腹痛的疗效。方法伴有胰管扩张的中晚期胰腺癌患者61例分为2组，支架组30例（支架植入失败而剔除2例），采用内镜逆行胰胆管造影术、胆管支架内引流和胰管支架内引流术；对照组31例，采用内镜逆行胰胆管造影术和单纯胆管支架内引流术。观察术前后血淀粉酶，记录疼痛视觉模拟评分法（VAS）评分、疼痛缓解率、生存时间和并发症情况。组间率的比较采用卡方检验，组间计量资料比较采用t检验，组内VAS评分的比较采用单因素方差分析。结果支架组和对照组术后1d血淀粉酶分别为（62．65±27．31）U／L和（76．17±21．64）U／L，两组差异无统计学意义（t=0．07，P〉0．05）。支架组术后3个月VAS评分（3．99±1．13）较术前（6．53±1．87）明显降低（F=0．535，P〈0．05），支架组术后疼痛缓解率（59．09％）明显高于对照组（26．09％），差异有统计学意义（x2=19．06，P〈0．05）。支架组和对照组的中位生存期分别为8．66个月和8．40个月，差异无统计学意义（t=0．11，P〉0．05）。两组均未观察到严重并发症的发生。结论胰管支架可以减轻伴有胰管扩张的中晚期胰腺癌患者疼痛，但不延长生存期。

Aberrant Methylation in CpG Islands of pl5 and pl6 Tumor Suppressor Genes in Pancreatic Cancer Tissue

Objective： To detect the aberrant methylation patterns in the CpG islands of p16 and p15 tumor suppressor genes, and to analyze its correlation with pancreatic carcinogenesis and with clinicopathological characteristics of patients with pancreatic cancer （PC）. Methods： The methylation-specific polymerase chain reaction （MSP） method was used to monitor methylation patterns in the CpG islands of p15 and p16 genes from 29 cases of PC and 3 cases of chronic pancreatitis （CP） paraffin-embedded tissue, as well as 2 cases of normal liver tissues and 12 cases of normal blood samples. Results： p15 and p16 genes were detected to show unmethylation patterns and no amplification using methylation-specific primers in control group. The aberrant methylation rates of p16 in carcinoma tissue and adjacent noncarcinoma tissue were 37.9% （11 of 29 cases） and 34.5% （10 of 29 cases） respectively. Of the 11 aberrant methylated samples, 5 showed complete methylation and 6 hemimethylation. The methylation rates of p15 gene in carcinoma tissue and adjacent noncarcinoma tissue were 27.5% （8/29） and 24.4% （7/29） respectively. Of the 8 aberrant methylated samples, 3 showed complete methylation and 5 hemimethylation. In 6 PC samples, aberrant methylation in CpG islands of both p15 and p16 genes existed simultaneously. The aberrant methylation patterns in CpG islands of p15 and p16 genes had no close correlation with the clinicopathological characteristics （age, sex, smoking, volume of primary tumor, differentiation, clinical stage and histological classification） of the patients with PC （P〉0.05）. Conclusion： The aberrant methylation in CpG islands of p15 and p16 genes could be regarded as an early molecular event in PC and had no close correlation with the clinicopathological characteristics of the patients with PC.

Treatment of Unresectable Carcinoma of Pancreas with ^(125)I Implantation and ^(125)I Plus Gemcitabine

Objective: To study the role of 125 I and 125 I plus gemcitabine (GEM) in treatment of unresectable carcinoma of pancreas. Methods: From April 2000 to April 2003, 38 untreated patients with locally advanced pancreatic cancer (LAPC) were collected and randomized into two groups: Arm A 125 I (18 patients) and Arm B 125 I+GEM (20 patients). Eligibility criteria were: cytologically and pathologically proven pancreatic carcinoma, Karnofsky performance status (kps) 60 80, age 18 75 years, adequate hematological, renal and liver function, and controllable pain. Arm A patients were treated with 125 I implants. Arm B patients started chemotherapy within 10 14 d post operatively following the implant procedure. Chemotherapy doses were as follows: GEM 1 000 mg/m 2 weekly × 3 followed by 1 week of rest for 3 cycles. In addition, all patients underwent laparotomy and surgical staging. The surgical procedures performed were biopsy, gastric bypass and biliary bypass. The total activity and number of seeds used were as recommended by Anderson. The mean activity, minimal peripheral dose (MPD), and volume of implants were 20 mCi, 14 000 cGy, and 53 cm 3, respectively. Results: Overall response rate (CR+PR) in Arm A was 37.6% and in Arm B it was 44.5% ( P >0.05). PR median duration in Arm A was 6.7 months and in Arm B it was 4.8 months ( P <0.05). Clinical benefit response was experienced by 11.7 % of Arm A compared with 42.1% of Arm B ( P <0.05). The incidences of hematological toxicity (such as neutropenia) between Arm A and Arm B were 5.8% and 21.1%, respectively ( P >0.05). The survival rates of 12 and 24 month were 32.5%, 16.3% for Arm A and 61%, 38.7% for Arm B ( P =0.04). The rate of complication of Arm A was lower than that of Arm B without statistical significance. Conclusion: To some extent, 125 I or 125 I plus GEM is able to lead to a moderate objective response for LAPC with obstructive jaundice on the base of biliary bypass or/and gastric bypass, but 125 I plus GEM is more effective than 125 I in improvement of the quality of life and survival rate in patients with LAPC.

Strategy to differentiate autoimmune pancreatitis from pancreas cancer

Autoimmune pancreatitis (AIP) is a newly described entity of pancreatitis in which the pathogenesis appears to involve autoimmune mechanisms. Based on histological and immunohistochemical examinations of various organs of AIP patients, AIP appears to be a pancreatic lesion reflecting a systemic "IgG4-related sclerosing disease". Clinically, AIP patients and patients with pancreatic cancer share many features, such as preponderance of elderly males, frequent initial symptom of painless jaundice, development of new-onset diabetes mellitus, and elevated levels of serum tumor markers. It is of uppermost importance not to misdiagnose AIP as pancreatic cancer. Since there is currently no diagnostic serological marker for AIP, and approach to the pancreas for histological examination is generally difficult, AIP is diagnosed using a combination of clinical, serological, morphological, and histopathological features. Findings suggesting AIP rather than pancreatic cancer include:fluctuating obstructive jaundice; elevated serum IgG4 levels; diffuse enlargement of the pancreas; delayed en- hancement of the enlarged pancreas and presence of a capsule-like rim on dynamic computed tomography; low apparent diffusion coefficient values on diffusion-weighted magnetic resonance image; irregular narrowing of the main pancreatic duct on endoscopic retrograde cholangiopancreatography; less upstream dilatation of the main pancreatic duct on magnetic resonance cholangiopancreatography, presence of other organ involvement such as bilateral salivary gland swelling, retroperitoneal fibrosis and hilar or intrahepatic sclerosing cholangitis; negative work-up for malignancy including endoscopic ultrasound-guided fine needle aspiration; and steroid responsiveness. Since AIP responds dramatically to steroid therapy, accurate diagnosis of AIP can avoid unnecessary laparotomy or pancreatic resection.

β-catenin up-regulates the expression of cyclinD1, c-myc and MMP-7 in human pancreatic cancer: Relationships with carcinogenesis and metastasis

AIM:To investigate whether abnormal expression of β-catenin in conjunction with overexpression of cyclinD1, c-myc and matrix metalloproteinase-7 (MMP-7) correlated with the carcinogenesis, metastasis and prognosis of pancreatic cancer, and to analyze the relationship of β-catenin expression with cyclinDl, c-myc and MMP-7 expression. METHODS: Using immunohistochemistry,we examined the expression of β-catenin, cyclinD1,c-myc and MMP-7 in 47 pancreatic adenocarcinoma tissues, 12 pancreatic intraepithelial neoplasia (PanIN) and 10 normal pancreases, respectively. Proliferation cell nuclear antigen was also tested as the index of proliferative activity of pancreatic cancer cells. RESULTS: In 10 cases of normal pancreatic tissues, epithelial cells showed equally strong membranous expression of β-catenin protein at the cell-cell boundaries, but the expression of cyclinDl, c-myc and MMP-7 was negative. The expression of β-catenin, cyclinD1, c-myc and MMP-7 in PanIN and pancreatic adenocarcinoma tissues had no significant difference [6/12 and 32/47 (68.1%), 6/12 and 35/47 (74.5%), 5/12 and 33/47 (70.2%), 7/12 and 30/47 (63.8%), respectively]. The abnormal expression of β-catenin was significantly correlated to metastasis and one-year survival rate of pancreatic cancer, but had no relation with size, differentiation and cell proliferation. The expression of cyclinD1 was correlated with cell proliferation and extent of differentiation, but not with size, metastasis and one-year survival rate of the pancreatic cancer. The expression of c-myc was not correlated with size, extent of differentiation, metastasis and 1-year survival rate, but closely with cell proliferation of pancreatic cancer. The overexpression of MMP-7 was significantly associated with metastasis and 1-year survival rate of pancreatic cancer,but not with size, extent of differentiation and cell proliferation.There was a highly significant positive association between abnormal expression of β-catenin and overexpression of cyclinD1, c-myc and MMP-7 not only in PanIN (r= 1.000, 0.845, 0.845), but also in pancreatic cancer (r= 0.437, 0.452, 0.435). CONCLUSION: The abnormal expression of β-catenin plays a key role in the carcinogenesis and progression of human pancreatic carcinoma by up-regulating the expression of cyclinDl, c-myc and MMP-7, resulting in the degradation of extracellular matrix and uncontrolled cell proliferation and differentiation,β-catenin abnormal expression and MMP-7 overexpression may be considered as two useful markers for determining metastasis and prognosis of human pancreatic cancer.

Pancreatic ductal adenocarcinoma screening:New perspectives

Pancreatic ductal adenocarcinoma accounts for more than 90% of all pancreatic cancers and its incidence has increased significantly worldwide.Patients with pancreatic ductal adenocarcinoma have a poor outcome and more than 95% of the people affected die from the disease within 12 mo after diagnosis.Surgery is the first-line treatment in the case of resectable neoplasm,but only 20% of patients are candidates for this approach.One of the reasons there are few candidates for surgery is that,during the early phases of the disease,the symptoms are poor or non-specific.Early diagnosis is of crucial importance to improve patient outcome;therefore,we are looking for a good screening test.The screening test must identify the disease in an early stage in order to be effective;having said this,a need exists to introduce the concept of "early" ductal adenocarcinoma.It has been reported that at least five additional years after the occurrence of the initiating mutation are required for the acquisition of metastatic ability of pancreatic adenocarcinoma and patients die an average of two years thereafter.We have reviewed the most recent literature in order to evaluate the present and future perspectives of screening programs of this deadly disease.

KNOCKDOWN OF SURVIVIN EXPRESSION BY SMALL INTERFERING RNA SUPPRESSES PROLIFERATION OF TWO HUMAN CANCER CELL LINES

Objective To construct an expression vector of small interfering RNA （siRNA） against survivin and observe its effects on survivin expression and proliferation of human pancreatic cancer cell line PC-2 and breast cancer cell line MCF-7. Methods Constructed an expression vector of siRNA against survivin and transfected it into PC-2 and MCF-7 cells using lipofectamine^TM 2000. The expression of survivin was detected by semi-quanfifive RT-PCR and immunohistochemistry, and its effects on proliferation of PC-2 and MCF-7 cells were detected by MTT assay. Results The introduction of sequence-specific siRNA could efficiently suppress survivin expression at both mRNA and protein levels in the two cancer cell lines. In PC-2 cells, the expression inhibition rates were 81.25% at mRNA level and 74.24% at protein level In MCF-7 cells, the expression inhibition rates were 64.91% at mRNA level and 79. 72% at protein level The proliferation of PC-2 and MCF-7 cells was also suppressed, and24 and 48 hours after the cells were reseeded, the proliferation inhibition rates of PC-2 cells were 28. 00% and 33. 38%, and that of MCF-7 cells were 31.58% and 33.02%, respectively. Conclusions The expression vector of siRNA against survivin can block survivin expression in PC-2 and MCF-7 cells efficiently and specifically. Down regulation of survivin expression can suppress proliferation of PC-2 and MCF-7 cells. Survivin RNAi may have potential value in gene therapy of human cancers.

Diagnostic role of secretin-enhanced MRCP in patients with unsuccessful ERCP

AIM:To evaluate the value of MR cholangiopancreatography (MRCP)in patients in whom endoscopic retrograde cholangiopancreatography(ERCP)was unsuccessfully performed by experts in a tertiary center. METHODS:From January 2000 to June 2003,22 patients fulfilled the inclusion criteria.The indications for ERCP were obstructive jaundice(n=9),abnormal liver enzymes(n=8), suspected chronic pancreatitis(n=2),recurrent acute pancreatitis(n=2),or suspected pancreatic cancer(n=1). The reasons for the ERCP failure were the postsurgical anatomy(n=7),duodenal stenosis(n=3),duodenal diverticulum(n=2),and technical failure(n=10).MRCP images were evaluated before and 5 and 10 rain after i.v. administration of 0.5 IU/kg secretin. RESULTS:The MRCP images were diagnosed in all 21 patients.Five patients gave normal MR findings and required no further intervention.MRCP revealed abnormalities(primary sclerosing cholangitis,chronic pancreatitis,cholangitis,cholecystolithiasis or common bile duct dilation)in 20 patients,who were followed up clinically.Four patients subsequently underwent laparotomy(hepaticojejunostomy in consequence of common bile duct stenosis caused by unresectable pancreatic cancer;hepaticotomy+Kehr drainage because of insufficient biliary-enteric anastomosis;choledochoj- ejunostomy,gastrojejunostomy and cysto-Wirsungo gastrostomy because of chronic pancreatitis,or choledochojejunostomy because of common bile duct stenosis caused by chronic pancreatitis).Three patients participated in therapeutic percutaneous transhepatic drainage.The indications were choledocholithiasis with choledochojejunostomy,insufficient biliary-enteric anastomosis,or cholangiocarcinoma. CONCLUSION:MRCP can assist the diagnosis and management of patients in whom ERCP is not possible.

Antiangiogenic therapy for human pancreatic carcinoma xenografts in nude mice

AIM: To investigate the anti-tumor effects of antiangiogenic therapy (a combination of TNP-470, an antiangiogenic compound, with gemcitabine, an antimetabolite) on human pancreatic carcinoma xenografts and its mechanism. METHODS: A surgical orthotopic implantation (SOI) model was established by suturing small pieces of SW1990 pancreatic carcinoma into the tail of pancreas in nude male mice. Mice then received either single therapy (n = 24) or combined therapy (n = 32). Mice receiving single therapy were randomly divided into control group, G100 group receiving 100 mg/kg gemcitabine IP on d O, 3, 6 and 9 after transplantation, and T30 group receiving 30 mg/kg TNP-470 s.c on alternate days for 8 wk. Mice receiving combined therapy were randomly divided into control group, T15 group, G50 group and combination group (TNP-470 30 mg/kg and gemcitabine 50 mg/kg). Animals were killed 8 wk after transplantation. Transplanted tumors, liver, lymph node and peritoneum were removed. Weight of transplanted tumors, the T/C rate (the rate of mean treated tumor weight to mean control tumor weight), change of body weight, metastasis rate, and 9-wk survival rate were investigated. Tumor samples were taken from the control group, T30 group, G100 group and combination group. PCNA index (PI) and microvessel density (MVD) were investigated by immunohistochemical staining for PCNA and factor VIII, respectively. RESULTS: There was a significant inhibitory effect on primary tumor growth of pancreatic carcinoma in G100 group, compared to T30 group, whereas tumor metastasis was significantly inhibited in T30 group compared to G100 group. There was no significant improvement in survival rate in these two groups. No significant inhibitory effect on tumor growth and metastasis in T15 group and G50 group. However, significant anti-tumor and anti-metastatic effects were observed in the combination group with a significant improvement in survival rate. The inhibitory effect on tumor growth in combination group enhanced 2 times in comparison with G50 group and 5 times in comparison with T15 group. Moreover, 25% of the animals hearing tumors were cured by the combination therapy. The levels of MVD and PI were 14.50±5.93 and 0.41±0.02,12.38±1.60 and 0.30±0.07, 7.13±2.99 and 0.37±0.03, and 5.21±1.23 and 0.23±0.02 respectively in the control group, G100 group, T30 group and combination group. A significant inhibitory effect on PI level and MVD level was observed in G100 group and T30 group respectively whereas both MVD and PI levels were significantly inhibited in the combination group (P<0.05). CONCLUSION: Antiangiogenic therapy shows significant anti-tumor and anti-metastatic effects, and is helpful to reduce the dosage of cytotoxic drugs and the side effects. These effects are related to the antiangiogenic effect of TNP-470 and cytotoxic effect of gemcitabine.

Adjuvant and neoadjuvant treatment in pancreatic cancer

Pancreatic adenocarcinoma is one of the most aggressive human malignancies,ranking 4th among causes for cancer-related death in the Western world including the United States.Surgical resection offers the only chance of cure,but only 15 to 20 percent of cases are potentially resectable at presentation.Different studies demonstrate and confirm that advanced pancreatic cancer is among the most complex cancers to treat and that these tumors are relatively resistant to chemotherapy and radiotherapy.Currently there is no consensus around the world on what constitutes"standard"adjuvant therapy for pancreatic cancer.This controversy derives from several studies,each fraught with its own limitations.Standards of care also vary somewhat with regard to geography and economy,for instance chemo-radiotherapy followed by chemotherapy or vice versa is considered the optimal therapy in North America while chemotherapy alone is the current standard in Europe.Regardless of the efforts in adjuvant and neoadjuvant improved therapy,the major goal to combat pancreatic cancer is to find diagnostic markers,identifying the disease in a pre-metastatic stage and making a curative treatment accessible to more patients.In this review,authors examined the different therapy options for advanced pancreatic patients in recent years and the future directions in adjuvant and neoadjuvant treatments for these patients.

Presence of CCK-A, B receptors and effect of gastrin and cholecystokinin on growth of pancreatobiliary cancer cell lines

AIM: To investigate the effects of gastrin and cholecystokinin (CCK) and their specific antagonists on the growth of pancreatic and biliary tract cancer cell lines. METHODS: Five pancreatic and 6 biliary cancer cell lines with 2 conrtol cells were used in this study. Cell proliferation study was done using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) test and direct cell count method. Reverse transcription-polymerase chain reaction (RT-PCR) and slot blot hybridization were performed to examine and quantify the expression of hormonal receptors in these cell lines. RESULTS: SNU-308 showed a growth stimulating effect by gastrin-17, as did SNU-478 by both gastrin-17 and CCK-8. The trophic effect of these two hormones was completely blocked by specific antagonists (L-365, 260 for gastrin and L-364, 718 for CCK). Other cell lines did not respond to gastrin or CCK. In RT-PCR, the presence of CCK-A receptor and CCK-B/gastrin receptor mRNA was detected in all biliary and pancreatic cancer cell lines. In slot blot hybridization, compared to the cell lines which did not respond to hormones, those that responded to hormones showed high expression of receptor mRNA. CONCLUSION: Gastrin and CCK exert a trophic action on some of the biliary tract cancers.

Clinical value of serum CA19-9 levels in evaluating resectability of pancreatic carcinoma

AIM:To evaluate the clinical value of serum CA19-9 levels in predicting the respectability of pancreatic carcinoma according to receiver operating characteristic(ROC) curve analysis. METHODS:Serum CA19-9 levels were measured in 104 patients with pancreatic cancer which were possible to be resected according to the imaging. ROC curve was plotted for the CA19-9 levels. The point closest to the upper left-hand corner of the graph were chosen as the cut-off point. The sensitivity,specificity,positive and negative predictive values of CA19-9 at this cut-off point were calculated. RESULTS:Resectable pancreatic cancer was detected in 58(55.77%) patients and unresectable pancreatic cancer was detected in 46(44.23%) patients. The area under the ROC curve was 0.918 and 95% CI was 0.843-0.992. The CA19-9 level was 353.15 U/mL,and the sensitivity and specificity of CA19-9 at this cut-off point were 93.1% and 78.3%,respectively. The positive and negative predictive value was 84.38% and 90%,respectively. CONCLUSION:Preoperative serum CA19-9 level is a useful marker for further evaluating the resectability of pancreatic cancer. Obviously increased serum levels of CA19-9(> 353.15 U/mL) can be regarded as an ancillary parameter for unresectable pancreatic cancer.

KAI1 is a potential target for anti-metastasis in pancreatic cancer cells

AIM: To investigate whether KAI1, as a metastasis suppressor gene, is associated with invasive and metastatic ability of pancreatic cancer cells.METHODS: KAI1 gene was transfected into pancreatic cancer cell line MiaPaCa Ⅱ by liposomes selected with G418. Expression of transfected cells was measured by Western blotting, immunofluorescence and immunocytochemistry. Tumor cell invasion and metastatic ability were detected through gelatinase activity and reconstituted basement membrane (Matrigel) assay. pCMV-KAI1 was directly injected into the heterotopic human pancreatic adenocarcinoma successfully established in the groin of BALB/C nude mice, by subcutaneous injection of MiaPaCa Ⅱ pancreatic cancer cells. The statistical analysis between groups was determined by Student's two tailed t test.RESULTS: By Western blotting, MiaPaCa Ⅱ cells transfected by KAI1 gene indicated KAI1 expression at approximately 29.1 kDa. Cytoplasm staining was positive and uniformly spread in transfected cancer cells, using immunohistochemistry and immunofluorescence. The most obvious difference was present after 30 h (MiaPaca Ⅱ 43.6 ± 9.42, pCMV-MiaPaca Ⅱ 44.8 ± 8.56, pCMV-KAI1-MiaPaca Ⅱ 22.0 ± 4.69, P < 0.05). Gelatinolysis revealed a wider and clearer band of gelatinolytic activity in non-transfected than in transfected cells (MiaPaCa Ⅱ cells 30.8 ± 0.57, transfected cells 28.1 ± 0.65, P < 0.05). In vivo tumor growth rates of KAI1 transfectants with KAI1-Lipofectamine 1.22 ± 0.31 in A group were lower than control 4.61 ± 1.98 and pCMV-KAI 11.67 ± 0.81. Analyses of metastases with and without KAI1 transfection in mice were different in liver and lung between controls 1.62 ± 0.39, 0.45 ± 0.09, pCMV-KAI 1.01 ± 0.27, 0.33 ± 0.09 and KAI1-Lipofectamine 0.99 ± 0.21, 0.30 ± 0.09 respectively (P < 0.05).CONCLUSION: High expression of KAI1 gene was found in transfected MiaPaCa Ⅱ human pancreatic cancer cells with lower metastatic ability. KAI1 gene plays an important role in inhibiting metastasis of pancreatic cancer after direct injection into pancreatic adenocarcinoma. These results show that the suppressed invasion and motor function of pancreatic cancer cells may be a key reason why the KAI1 gene controls pancreatic cancer cell metastasis.

Reversal of the phenotype by K-ras^(val12) silencing mediated by adenovirus-delivered siRNA in human pancreatic cancer cell line Panc-1

AIM: To investigate the in vitro antitumor effect of adenovirus-mediated small interfering RNAs (siRNAs) on pancreatic cancer and the associated mechanism. METHODS: A 63-nucleotide (nt) oligonucleotide encoding K-rasval12 and specific siRNA were introduced into pSilencer 3.1-H1, then the H1-RNA promoter and siRNA coding insert were subcloned into pAdTrack to get plasmid pAdTrackH1-Avasval12. After homologous recombination in bacteria and transfections of such plasmids into a mammalian packaging cell line 293, siRNA expressing adenovirus Adh1-K-rasval12 was obtained. Stable suppression of K-rasval12 was detected by Northern blot and Western blot. Apoptosis in Panc-1 cells was detected by flow cytometry. RESULTS: We obtained adenovirus AdHl-K-rasval12 carrying the pSilencer 3.1-H1 cassette, which could mediate gene silencing. Through siRNA targeted K-rasval12, the oncogenic phenotype of cancer cells was reversed. Flow cytometry showed that apoptotic index of Panc-1 cells was significantly higher in the AdH1-K-rasval12-treatment group (18.70% at 72 h post-infection, 49.55% at 96 h post-infection) compared to the control groups (3.47%, 3.98% at 72 and 96 h post-infection of AdH1-empty, respectively; 4.21%, 3.78% at 72 and 96 h post-infection of AdHl-p53, respectively) (P<0.05). CONCLUSION: These results demonstrate that adenoviral vectors can be used to mediate RNA interference (RNAi) to induce persistent loss of functional phenotypes. In gene therapy, the selective down-regulation of only the mutant version of a gene allows for highly specific effects on tumor cells, while leaving the normal cells untouched. In addition, the apoptosis of pancreatic cancer cell line Panc-1 can be induced after AdH1-K-rasval12 infection. This kind of adenovirus based on RNAi might be a promising vector for cancer therapy.

Expression of inducible nitric oxide synthase and cyclooxygenase-2 in pancreatic adenocarcinoma:Correlation with microvessel density

AIM:Cydooxygenases (COX) are key enzymes for conversion of arachidonic acid to prostaglandins.Nitric oxide synthase (NOS) is the enzyme responsible for formation of nitric oxide. Both have constitutive and inducible isoforms.The inducible isoforms (iNOS and COX-2) are of great interest as regulators of tumor angiogenesis,tumorigenesis and inflammatory processes.This study was to clarify their role in pancreatic adenocarcinomas. METHODS:We investigated the immunohistochemical iNOS and COX-2 expression in 40 pancreatic ductal adenocardnomas of different grade and stage.The results were compared with microvessel density and dinicopathological data. RESULTS:Twenty-one (52.5%) of the cases showed iNOS expression,15 (37.5%) of the cases were positive for COX-2. The immunoreaction was heterogeneously distributed within the tumors.Staining intensity was different between the tumors.No correlation between iNOS and COX-2 expression was seen.There was no relationship with microvessel density. However,iNOS positive tumors developed more often distant metastases and the more malignant tumors showed a higher COX-2 expression.There was no correlation with other clinicopathological data. CONCLUSION:Approximately half of the cases expressed iNOS and COX-2.These two enzymes do not seem to be the key step in angiogenesis or carcinogenesis of pancreatic adenocarcinomas.Due to a low prevalence of COX-2 expression,chemoprevention of pancreatic carcinomas by COX-2 inhibitors can only achieve a limited success.

Effect of deleted pancreatic cancer locus 4 gene transfection on biological behaviors of human colorectal carcinoma cells

AIM: To investigate the effect of deleted pancreatic cancer locus 4 (DPC4) gene transfection on biological behaviors of human colorectal carcinoma cells and the role of DPC4 gene in colorectal carcinogenesis. METHODS: PcDNA3.1-DPC4 plasmid was re-constructed by gene-recombination technology. SW620 cells, a human colorectal carcinoma cell line, were transfected with PcDNA3.1-DPC4 plasmid using lipofectamine transfecting technique. Transfected cells were selected with G418. Expression of Smad4 protein was detected in cells transfected with DPC4 gene by immunohistochemistry and Western blot. Biological characterristics of transfected cells were evaluated by population-doubling time and cloning efficiency. Alterations of percentage of S phage cells (S%) and apoptosis rate were determined by flow-cytometry. RESULTS: PcDNA3.1-DPC4 plasmid was constructed successfully. SW620 cells transfected with PcDNA3.1-DPC4 plasmid (DPC4+-SW620 cells) showed a strong intracellular expression of Smad4 protein, and the positive signal was localized in cytoplasm and nuclei, mainly in cytoplasm, where the expressions of Smad4 protein in SW620 cells transfected with PcDNA3.1 plasmid (PcDNA3.1-SW620 cells) and non-transfected SW620 cells (SW620 cells) were weaker than those in DPC4+-SW620 cells. The population-doubling time in DPC4+-SW620 cells (116 h) was significantly longer than that in SW620 cells (31 h) and PcDNA3.1-Sw620 cells (29 h) (P<0.01). The cloning efficiencies of DPC4+-SW620 cells (12%) were markedly lower than those of SW620 cells (69%) and PcDNA3.1-Sw620 cells (67%) (P<0.01). Compared with SW620 cells and PcDNA3.1-Sw620 cells, the Go-G1% of DPC4+-SW620 cells was obviously higher and the S% was markedly lower (P<0.05). Apoptosis rate of DPC4+-SW620 cells was significantly higher than that of SW620 cells and PcDNA3.1-SW620 cells. CONCLUSION: PcDNA3.1-DPC4 plasmid can be successfully re-constructed and stably transfected into human SW620cells, thereby the cells can steadily express Smad4. DPC4 protein may regulate proliferation of colorectal carcinoma cells by inhibiting cell growth and inducing cell apoptosis.

Effect of gemcitabine on the expression of apoptosis-related genes in human pancreatic cancer cells

AIM： TO investigate the expression of genes involved in the gemcitabine-induced cytotoxicity in human pancreatic cancer cells. METHODS： A human pancreatic cancer cell line, PANC-1, was cultured. 1 × 10^4 PANG-1 cells were plated in 96-well microtiter plates. After being incubated for 24 h, gemcitabine was added to the medium at concentrations ranging 2.5 -1 000 mg/L. The AlamarBlue dye method was used for cell growth analysis. DNA fragmentation was quantitatively assayed using a DNA fragmentation enzyme-linked immunosorbent assay （ELISA） kit. PAP and TP53INP1 mRNA expression was determined using the reverse transcription-polymerase chain reaction with semi-quantitative analysis. The expression of GSK-3β and phospho-GSK-3β proteins was examined with Western blot analysis. RESULTS： The IC50 for the drug after a 48-h exposure to gemcitabine was 16 mg/L. The growth of PANC-1 cells was inhibited by gemcitabine in a concentration-dependent manner （P〈 0.0001） and the cell growth was also inhibited throughout the time course （P〈0.0001）. The DNA fragmentation rate in the gemcitabine-treated group at 48 h was 44.7 %, whereas it was 25.3 % in the untreated group. The PAP mRNA expression was decreased after being treal^l with gemcitabine, whereas the TP53INP1 mRNA was increased by the gemcitabine treatment. Western blot analysis showed that phospho- GSK-3βZ^ser9 was induced by the gemcitabine treatment. CONCLUSION： Gemcitabine suppresses PANC-1 cell proliferation and induces apoptosis. Apoptosis is considered to be associated with the inhibition of PAPand GSK-3β, and the activation of TP53INP1 and pospho- GSK-3β^ser9 .

Small invasive ductal carcinoma of the pancreas distinct from branch duct intraductal papillary mucinous neoplasm

Endoscopic ultrasonography （EUS） is a highly sensitive diagnostic method for the detection of small pancreatic carcinomas. Recently, there have been some reports describing the utility of contrast-enhanced harmonic EUS （CEH-EUS） which uses sonographic contrast agent for differentiation of a pancreatic mass. This report describes a case of small adenocarcinoma of the pancreas distinct from branch duct intraductal papillary mucinous neoplasm （IPMN） in which investigation by EUS took place every 6 mo and diagnosis was made accurately by additional CEH-EUS during the follow-up of the branch duct IPMN. A 68-year-old female was admitted to our hospital because of a branch duct IPMN in the pancreatic body. She had been followed-up by EUS every 6 too. However, after 2 years EUS demonstrated a low echoic area distinct from the branch duct IPMN which was vaguely discernible by EUS, and accurate sizing and differential diagnosis were considered difficult on the EUS imaging. CHEUS with Sonazoid revealed a hypovascular tumor and we suspected small pancreatic carcinoma. The histopathological diagnosis was adenocarcinoma （10 mm） in the pancreatic tail, distinct from the branch duct IPMN of the pancreatic body. EUS and CEH-EUS may play an important role in the correct diagnosis of small pancreatic tumors, including synchronous and metachronous occurrence of IPMN and ductal adenocarcinoma of the pancreas.