体外负载HSP70-K-ras突变多肽复合物树突细胞的抗胰腺癌作用

背景：K-ras突变多肽难以很好地被树突细胞（DC）捕获,诱导的抗肿瘤效应有限。目的：探讨热休克蛋白70（HSP70）-K-ras突变多肽复合物体外负载于DC的抗胰腺癌作用。方法：使HSP70与K-ras突变多肽在体外结合成复合物,负载于由人外周血单个核细胞体外诱导分化获得的DC。酶联免疫吸附测定（ELISA）检测DC的细胞因子分泌能力,流式细胞仪分析DC负载抗原前后的细胞表型变化,胆囊收缩素（CCK）-8法检测负载抗原后DC对同基因淋巴细胞的促增殖作用,以及激活的同基因淋巴细胞对人胰腺癌细胞株Patu8988、PANC-1和正常人肝细胞株L-02的细胞毒作用。结果：HSP70-K-ras突变多肽复合物可激活DC,最适浓度为0.75μg/ml,可使DC的白细胞介素（IL）-12、肿瘤坏死因子（TNF）-α分泌量和细胞表面CD80、CD83、CD86、HLA-DR表达率显著增高。0.75μg复合物可有效激活1×10^6个DC,刺激1×10^7个同基因淋巴细胞增殖,特异性杀伤具有相同12位点突变类型（GGT→GTT）的Patu8988细胞,杀伤率达52.9%±5.1%,对不同突变类型的PANC-1细胞（GGT→GAT）和正常人肝细胞杀伤作用不明显。结论：负载HSP70-K-ras突变多肽复合物的DC活性增强,可刺激同基因淋巴细胞产生高效而特异的抗胰腺癌效应。     

胰星状细胞对胰腺癌细胞株Patu8988侵袭和转移的影响

目的:探讨永生化人胰星状细胞(IPSC)对胰腺癌细胞株Patu8988侵袭和转移的影响.方法:制备IPSC上清,用IPSC上清和Patu8988共培养,以单独培养的Patu8988为对照,比较实验组与对照组细胞的增殖、黏附能力.侵袭、迁移能力,克隆形成以及抵抗H2O2诱导的Patu8988凋亡能力.结果:与单独培养的胰腺癌细胞株Patu8988相比,IPSC上清对胰腺癌细胞株Patu8988细胞的增殖、黏附、迁移、侵袭能力及克隆形成能力有促进作用(均p<0.05),并能抑制H2O2诱导的Patu8988的凋亡(P<0.05).结论:胰星状细胞可能通过增强胰腺癌细胞株Patu8988的增殖、黏附、迁移、侵袭能力及克隆形成能力,并抑制其的凋亡,在胰腺癌的发展和转移中起重要作用.     

全反式维甲酸诱导胰腺癌细胞凋亡机制研究

目的 维甲酸类药物调节肿瘤细胞生长、分化和凋亡是其防治肿瘤的基础。本研究观察全反式维甲酸(ATRA)诱导体外胰腺癌细胞凋亡的可能机制。方法 胰腺癌细胞Patu8988与ATRA共同孵育。通过DNA断裂分析、TUNEL标记证实凋亡存在，并用流式细胞仪检测凋亡细胞比例。用RT-PCR和Western blot方法检测凋亡诱导过程中p53、bcl-2和bax基因的水平及其表达变化。结果 ATRA处理组细胞凋亡比例明显增加。TUNEL标记和DNA断裂分析发现典型凋亡特征。ATRA处理组bax和phospho-p53(Ser 46)表达上调，但bcl-2表达下调。结论 ATRA能诱导胰腺癌细胞凋亡，其分子机制可能与bcl-2/bax和p53的表达相关。     

Detection of K-ras point mutation and telomerase activity during endoscopic retrograde cholangiopancreatography in diagnosis of pancreatic cancer

AIM: To study the value of monitoring K-ras point mutation at codon 12 and telomerase activity in exfoliated cells obtained from pancreatic duct brushings during endoscopic retrograde cholangiopancreatography (ERCP) in the diagnosis of pancreatic cancer. METHODS: Exfoliated cells obtained from pancreatic duct brushings during ERCP were examined in 27 patients: 23 with pancreatic cancers, 4 with chronic pancreatitis. K-ras point mutation was detected with the polymerase chain reaction and restriction fragment-length polymorphism (PCR-RFLP). Telomerase activity was detected by PCR and telomeric repeat amplification protocol assay (PCR-TRAP-ELISA). RESULTS: The telomerase activities in 27 patients were measured in 21 exfoliated cell samples obtained from pancreatic duct brushings. D450 value of telomerase activities in pancreatic cancer and chronic pancreatitis were 0.446+/-0.27 and 0.041+/-0.0111, respectively. Seventy-seven point eight percent (14/18) of patients with pancreatic cancer and none of the patients with chronic pancreatitis showed telomerase activity in cells collected from pancreatic duct brushings when cutoff value of telomerase activity was set at 2.0. The K-ras gene mutation rate (72.2%) in pancreatic cancer was higher than that in chronic pancreatitis (33.3%) (P<0.05). In considering of both telomerase activities and K-ras point mutation, the total positive rate was 83.3%(15/18), and the specificity was 100%. CONCLUSION: Changes of telomerase activities and K-ras point mutation at codon 12 may be an early event of malignant progression in pancreatic cancer. Detection of telomerase activity and K-ras point mutation at codon 12 may be complementary to each other, and is useful in diagnosis of pancreatic cancer.     

培美曲塞敏感与耐药胰腺癌细胞株生物学行为观察及机制探讨

目的观察胰腺癌培美曲塞敏感株Patu8988和耐药株Patu8988/P生物学行为的差异,并探讨其可能的机制。方法取对数生长期的Patu8988、Patu8988/P细胞,分别采用双层软琼脂实验检测细胞集落生成能力、流式细胞仪检测细胞周期分布、Transwell小室检测细胞侵袭及转移能力,采用RT-RCR法、流式细胞仪检测胰腺癌细胞中的CD44mRNA及其蛋白。结果与Patu8988细胞比较,Patu8988/P细胞的克隆形成能力增强,G1期的细胞比例增加,S期减少,而侵袭转移能力减弱,CD44mRNA及其蛋白均表达增高,P均〈0.05。结论 Patu8988/P、Patu8988细胞的生物学行为有不同程度的差异,主要表现在前者集落生成能力增强,侵袭、转移能力减弱等;CD44表达升高可能是造成这种差异的原因之一。     

Growth inhibition induced by short hairpin RNA to silence survivin gene in human pancreatic cancer cells

BACKGROUND:Survivin is known to be overexpressed in various human malignancies,including pancreatic cancer,and mediates cancer cell proliferation and tumor growth,so the regulation of this molecule could be a new strategy for treating pancreatic cancer.In this study,short hairpin RNAs (shRNAs) specific to survivin were introduced into human pancreatic cancer Patu8988 cells to investigate the inhibitory effects on survivin expression and cell proliferation in vitro and in vivo.METHODS:Three kinds of shRNA sp...     

顺序特异性引物法快速检测胰腺癌K—ras基因点突变

目的：研究简捷、特异、敏感的检测胰腺癌K－ras基因点突变的方法及其在胰腺疾病中定性诊断的价值。方法：采用针对K－ras基因点突变方式（CGT、GAT、GTT）设计的顺序特异性引物（SSP），先后对胰腺癌石蜡包埋组织、冰冻新鲜组织、细针穿刺组织及胰液进行多聚酶链反应（PCR），扩增产物借助常规电泳和染色检测有无K－ras基因突变及突变方式。结果：胰腺癌石蜡包埋组织、冰冻新鲜组织、细针穿刺组织及胰液中K－ras基因点突变率分别为74．2％、95．1％、91．4％及94．1％，而所有被检测的慢性胰腺炎、胰岛素瘤、壶腹癌、胆管癌、十二指肠乳头癌及外伤胰腺的组织标本和胰液标本均无K－ras基因突变发生。结论：该检测法简便、快速、特异、敏感，具有临床实用性，可以作为鉴别胰腺肿块良恶性和诊断胰腺癌的一种方法。     

K-ras基因点突变对胰腺癌的诊断价值

背景传统的放射或超声检查早期诊断胰腺癌非常困难.目的研究胰腺良、恶性病变中的K-ras基因12密码子点突变情况,探讨K-ras基因点突变对早期胰腺癌的诊断价值.方法取23例胰腺癌和12例胰腺良性病变标本,经DNA提取后,行半巢式聚合酶链反应(PCR),扩增产物借助聚丙烯酰胺凝胶电泳检测有无K-ras基因点突变.结果胰腺癌和胰腺良性病变石蜡包埋组织的K-ras基因12密码子点突变率分别为65.2%(15/23)和33.3%(4/12)(P＜0.05).结论K-ras基因12密码子点突变的检测可能有助于胰腺癌,尤其是早期胰腺癌的诊断.     

胰腺癌组织K-ras基因第12密码子突变的定量检测

目的 检测胰腺癌及相应癌旁组织K-ras基因第12密码子的突变量,分析其与胰腺癌临床病理参数的关系.方法 应用肽核酸(peptide nucleic acid,PNA)钳制双荧光标记探针的实时定量PCR法检测93例胰腺癌组织及其癌旁组织中K-ras基因第12密码子的突变拷贝数,以突变百分率表示突变量.K-ras基因突变百分率=K-ras突变型拷贝数/(K-ras野生型拷贝数+K-ras突变型拷贝数)×100%.结果 胰腺癌及其癌旁组织的K-ras基因第12密码子突变率分别为83.9%和65.6%,相差显著(P＜0.05);它们的突变量分别为(13.385±1.745)%和(2.246±0.728)%,相差亦显著(P＜0.05).K-ras基因第12密码子突变量与临床病理参数无关.结论 胰腺癌及相应癌旁组织不仅存在K-ras基因突变率的差异,亦存在K-ras基因突变量的差异.     

尼卡地平对胰腺癌Patu8988株培美曲塞耐药的逆转作用

目的:探讨ABCG2拮抗剂-尼卡地平在体外安全剂量下能否逆转耐药,为临床应用提供实验基础.方法:采用噻唑蓝法(MTT)测定尼卡地平对Patu8988亲本和耐药细胞的安全使用浓度,测定单用培美曲塞和联合安全剂量的尼卡地平分别对两株细胞的IC50变化;分别采用DAPI核染色和细胞流式分析在耐药细胞中单用培美曲塞组和联合尼卡地平组凋亡差异.结果:MTT结果显示尼卡地平在浓度<4.85μmol/L(2.5 mg/L)时对细胞基本无不良反应,单用培美曲塞和联合安全剂量的尼卡地平对Patu8988亲本株细胞IC50无明显差异,而对耐药株细胞IC50有差异(P<0.05).流式细胞分析在耐药细胞中联合尼卡地平组凋亡比例高于单用培美曲塞组(32.27%±2.8% vs 50.5%±4.2%,P<0.05).结论:安全剂量下尼卡地平能提高胰腺癌Patu8988耐药细胞株对培美曲塞的敏感性.而对其亲本株无作用.     

Effect of K‐ras antisense oligodeoxynucleotides on human pancreatic cancer cell line PaTu 8988s

OBJECTIVE : To study the effect of K‐ras antisense oligodeoxynucleotides (ASODN) on human pancreatic cancer cell line PaTu 8988s at different times after treatment. METHODS : Human pancreatic cancer cells (PaTu 8988s) in exponential growth stage were used at a cell concentration of 1 × 10⁵/mL; 0.5 mL of the cell suspension was placed in each well of replicate 24‐well culture plates in the presence of different concentrations (50 and 100 μg/mL) of ASODN and sense oligodeoxynucleotides (SODN). Cell counts and 3‐[4,5‐dimethylthiazolzyl]‐2,5‐diphenyl tetrazolium bromide (MTT) assays were carried out 24, 48 and 72 h after treatment. RESULTS : At 12, 24, 48 and 72 h after ASODN treatment, the following rates of inhibition were observed: for 50 μg/mL, 42.3, 66.6, 69.6 and 74.6%, respectively; for 100 μg/mL, 66.2, 91.4, 98.2 and 98.3%, respectively. CONCLUSION : The inhibitory effect of ASODN began at 12 h post‐treatment and became more marked at 48–72 h. The higher the concentration of ASODN, the earlier the peak of inhibitory rate appears.     

Early detection of pancreatic cancer in patients with chronic pancreatitis: diagnostic utility of a K-ras point mutation in the pancreatic juice

OBJECTIVE: Point mutations of the K-ras oncogene at codon 12 have been described several months before the onset of pancreatic cancer in isolated cases of chronic pancreatitis (CP). The aim of this study was to evaluate the interest of a prospective follow-up of patients with CP and K-ras mutations at codon 12 in the detection of early pancreatic cancer. METHODS: From February 1996 to March 1998, 36 patients (mean age 52.6 yr, 31 men, five women) with CP (alcoholic: 61.1%, pancreas divisum: 5.6%, autoimmune: 5.6%, unknown origin: 27.7%) were included and then prospectively monitored (median duration of 22 months) for detection of pancreatic carcinoma. K-ras point mutations were examined by two-step polymerase chain reaction combined with restriction enzyme digestion in pancreatic juice collected during endoscopic retrograde pancreatography. RESULTS: Ten patients (27.8%) were positive for K-ras mutation. Patients with and without the mutation were not different with respect to age and sex ratio. K-ras mutations were homogeneously distributed according to the etiology (alcoholic vs nonalcoholic) and morphological characteristics (ductal stricture or mass vs none) of CP. A pancreatic carcinoma was discovered at an invasive stage in two patients, respectively at 7 and 17 months after disclosure of a K-ras mutation, versus none in patients without the mutation (p < 0.02). CONCLUSIONS: Presence of a K-ras gene mutation is not rare in patients with CP and represents an increased risk of developing pancreatic cancer. However, its utility for the detection of early pancreatic cancer remains doubtful in clinical practice.     

Patterns of K-ras codon 12 and 13 mutations found in pancreatic adenocarcinoma of 30 Chinese patients by microdissection, PCR and direct sequencing

Background and Aim:  To our knowledge there are few reports on the K-ras mutation pattern of pancreatic adenocarcinoma from Chinese mainland patients. We examined surgically resected formalin-fixed, paraffin-embedded primary pancreatic adenocarcinoma tissue blocks for the presence of activating point mutations at codon 12 and 13 of the K-ras gene.
Methods:  Mutations were detected through the use of microdissection, polymerase chain reaction (PCR) and direct sequencing. The results were confirmed by reverse sequencing.
Results:  The combination of microdissection, PCR and direct sequencing techniques resulted in a rapid and sensitive detection of K-ras mutations at codon 12 and 13. Twenty-five (83%) of the 30 pancreatic adenocarcinomas examined harbored K-ras mutation. Among the 25 pancreatic adenocarcinomas, 24 showed K-ras mutation at codon 12 (11 with GGT-GTT, seven with GGT-GAT, four with GGT-CGT, and two with GGT-TGT), and only one showed a GGC-TGC mutation at codon 13. In this study most of K-ras mutations at codon 12 were at the second base (72%, 18/25) with a transition/transversion ratio of 1 : 1.57 (7/11).
Conclusions:  The mutation profiles of K-ras at codon 12 in our pancreatic adenocarcinoma samples were significantly different from those of European and Japanese samples.     

Patterns of K-ras codon 12 and 13 mutations found in pancreatic adenocarcinoma of 30 Chinese patients by microdissection, PCR and direct sequencing

BACKGROUND AND AIM: To our knowledge there are few reports on the K-ras mutation pattern of pancreatic adenocarcinoma from Chinese mainland patients. We examined surgically resected formalin-fixed, paraffin-embedded primary pancreatic adenocarcinoma tissue blocks for the presence of activating point mutations at codon 12 and 13 of the K-ras gene. METHODS: Mutations were detected through the use of microdissection, polymerase chain reaction (PCR) and direct sequencing. The results were confirmed by reverse sequencing. RESULTS: The combination of microdissection, PCR and direct sequencing techniques resulted in a rapid and sensitive detection of K-ras mutations at codon 12 and 13. Twenty-five (83%) of the 30 pancreatic adenocarcinomas examined harbored K-ras mutation. Among the 25 pancreatic adenocarcinomas, 24 showed K-ras mutation at codon 12 (11 with GGT-GTT, seven with GGT-GAT, four with GGT-CGT, and two with GGT-TGT), and only one showed a GGC-TGC mutation at codon 13. In this study most of K-ras mutations at codon 12 were at the second base (72%, 18/25) with a transition/transversion ratio of 1 : 1.57 (7/11). CONCLUSIONS: The mutation profiles of K-ras at codon 12 in our pancreatic adenocarcinoma samples were significantly different from those of European and Japanese samples.     

全反式维甲酸对多种胰腺癌细胞的诱导凋亡作用

目的观察全反式维甲酸(all-trans retinoic acid,ATRA)能否诱导人胰腺癌细胞的凋亡。方法分别将人胰腺癌细胞SW1990、PaTu8988、BxPC3和ATRA共同孵育后,用MTT法检测细胞活性,分别用流式细胞仪检测、TUNEL和透射电镜观察细胞的凋亡。结果MTT法显示,ATRA对3株人胰腺癌细胞株SW1990、PaTu8988和BxPC3的生长均有明显的抑制作用(P<0.05)。流式细胞仪的检测、TUNEL和电镜的观察结果均证实ATRA诱导后,3株胰腺癌细胞株凋亡率均高于对照(P<0.01),并随诱导时间延长而增加。结论ATRA在体外能显著抑制多株胰腺癌细胞株的生长,并促进其凋亡。     

Significance of K-ras codon 12 point mutation in pancreatic juice in the diagnosis of carcinoma of the pancreas

The significance of K-ras codon 12 point mutation in pancreatic juice in the diagnosis of carcinoma of the pancreas is still unclear. The aim of this study was to evaluate the significance of K-ras codon 12 point mutation in pancreatic juice in the diagnosis of carcinoma of the pancreas. All of the 78 reports written from 1988 to 1996 on K-ras point mutation of carcinoma, mucin-producing tumors, and hyperplastic epithelia of the pancreas in both surgical or autopsy specimens and pancreatic juice are reviewed. As results, in surgical or autopsy specimens, K-ras mutation was found in 81% of ordinary duct cell carcinoma and in 53% of mucin-producing tumor of the pancreas; this mutation was also found in hyperplastic epithelia in chronic pancreatitis (7%) and in autopsy cases without pancreatic diseases. In pancreatic juice, K-ras mutation was found in 72% of ordinary pancreatic carcinoma and in 53% of mucin-producing tumor, respectively. In conclusion, most previous reports have indicated that K-ras mutation in pancreatic juice is useful for a diagnosis of pancreatic carcinoma. However, since K-ras gene mutation was also detected in non-tumorous lesions, the diagnosis of pancreatic carcinomas is not necessarily correct if it is based solely on the detection of K-ras mutation in pancreatic juice. Future studies should focus on analyzing the amino acid sequence of K-ras mutation or the combination of this mutation with other parameters such as tumor markers in pancreatic juice, to enhance its specificity and accuracy.     

Diagnosis of pancreatic cancer by cytology and measurement of oncogene and tumor markers in pure pancreatic juice aspirated by endoscopy

BACKGROUND/AIMS: Cytological examination of pancreatic juice is useful in the diagnosis of an occult cancer of the pancreas. The early diagnosis of pancreatic carcinoma using traditional radiographic or ultrasonographic methods is extremely difficult. METHODOLOGY: In order to detect an early pancreatic cancer, cytological examination, measurement of tumor marker, and detection of K-ras point mutation were performed using the samples of pure pancreatic juice aspirated endoscopically in patients who had symptoms or findings that suggested pancreatic disease. RESULTS: By routine ERP-cytology, positive cytologic results were obtained in 15 (4%) out of 359 patients without a mass. With the aid of intra-operative cytodiagnosis, all 15 occult neoplasms of the pancreas were successfully resected. One patient died from another disease without evidence of recurrence. However, the other patients were alive with no evidence of recurrence for an average of 5.5 years following surgery. The patients who had negative ERP-cytology results were observed, but no further cases of pancreatic cancer were found. The CEA levels in the pure pancreatic juice were significantly higher in patients with pancreatic cancer than in those with pancreatitis. K-ras point mutation at codon 12 was detected not only in cases of pancreatic cancer, but also in cases of chronic pancreatitis as well as control subjects. CONCLUSIONS: Cytological examination of pancreatic juice is useful in the diagnosis of an early and potentially curable in situ cancer of the pancreas. The CEA levels in the pure pancreatic juice provided useful information for differentiating the pancreatic cancer from chronic pancreatitis. K-ras point mutation at codon 12 in pancreatic juice was considered to be useful in identifying patients at high risk for the development of pancreatic cancer.     

Analysis of K-ras codon 12 mutations and p53 overexpression in colorectal nodule-aggregating tumors

BACKGROUND AND AIMS: Morphologically, colorectal nodule-aggregating tumors are quite different from polypoid-type colorectal tumors that develop via the adenoma-carcinoma sequence. Although polypoid-type colorectal tumors are well known to have a high incidence of K-ras gene mutation and p53 overexpression, colorectal nodule-aggregating tumors have not been examined in terms of genetic changes and clinicopathological features. In the present study, therefore, we analysed the clinicopathological features, genetic changes in K-ras codon 12, and p53 overexpression in colorectal nodule-aggregating tumors. METHODS: A total of 18 colorectal nodule-aggregating tumors were surgically resected and then analysed clinicopathologically. Immunohistochemistry and polymerase chain reaction-single stranded conformational polymorphism were performed to analyse p53 abnormalities in the tumors. K-ras codon 12 mutations were screened out by the polymerase chain reaction-restriction fragment length polymorphism method and analysed by fluorescence direct sequencing. RESULTS: p53 overexpression was observed in six lesions (33%). p53-overexpressing cells were observed in parts of carcinoma or adenoma showing high-grade atypia. Four of the 10 (40%) samples had a p53 gene mutation. Nine of the 18 (50%) samples had a K-ras codon 12 point mutation. In eight cases (89%), the mutations of the K-ras codon 12 were of the same type: GGT (glycine) to GTT (valine). CONCLUSIONS: The colorectal nodule-aggregating tumor has distinctive characteristics showing a morphological phenotype of the superficial-type tumors and genotype of the polypoid tumors in terms of K-ras gene mutation and p53 overexpression.     

端粒酶逆转录酶基因反义寡核苷酸抑制肺癌细胞端粒酶活性和诱导细胞凋亡

目的 研究端粒酶逆转录酶（hTERT)基因反义寡核苷酸（ASODN）对肺癌细胞端粒酶活性和细胞凋亡的影响。方法 实验分为ASODN组、正义寡核苷酸（SODN）组和空白对照组,所用ASODN和SODN的浓度分别为10μmol/L,脂质体为16mg/L,采用端粒重复扩增法、逆转录－聚合酶链反应、Western Blot及流式细胞术分别观察各组端粒酶活性、hTERP mRNA和蛋白质表达以及细胞凋亡。结果 ASODN组显著下调或抑制肺癌细胞端粒酶活性和hTERT表达,但直到第21天才出现细胞凋亡增多。结论 端粒酶活性与hTERT表达密切相关。     

沙利度胺对人胰腺癌细胞细胞动力学和VEGF表达的影响

背景：研究显示沙利度胺及其类似物具有免疫调节、抗血管生成、抗炎等多方面的作用,其对多发性骨髓瘤和一些实体瘤的抗肿瘤作用与其免疫调节活性以及抗血管生成、抗增殖和促凋亡特性有关。目的：观察沙利度胺对人胰腺癌细胞细胞动力学和血管内皮生长因子（VEGF）表达的影响,探讨其用于胰腺癌临床辅助治疗的可能性。方法：以沙利度胺干预人胰腺癌细胞株Patu-898848h,MTT实验检测细胞增殖,流式细胞术检测细胞周期和细胞凋亡,RT—PCR检测VEGFmRNA表达。结果：经不同浓度沙利度胺干预的Patu-8988细胞,生长抑制率、G0／G1期细胞比例和细胞凋亡率均显著高于溶剂对照组（P〈0．05）,VEGF异构体VEGF121、VEGF165mRNA表达显著低于溶剂对照组（P〈0．05）。结论：沙利度胺能从多方面对胰腺癌生长产生抑制作用,包括直接抑制癌细胞增殖、诱导细胞周期G0／G1期阻滞和早期凋亡,以及通过抑制VEGF转录而抑制肿瘤血管发生。