生长抑素及其2型受体与胰腺癌

生长抑素在体内有着广泛的生物学活性。研究表明,生长抑索及其类似物可以和生长抑素2型受体（SSTR2）结合发挥直接抗肿瘤细胞增殖的作用。少部分胰腺癌组织中存在着SSTR2的表达,大多数不表达SSTR2的胰腺癌则通过在细胞表面的再表达也可发挥抑制肿瘤生长的作用。现就胰腺癌中生长抑素及SSTR2的研究进展作一综述。     

Anti-angiogenic effects of somatostatin receptor subtype 2 on human pancreatic cancer xenografts.

Somatostatin receptor subtypes, especially subtype 2 (SSTR2), exert their antitumor (cytostatic and/or cytotoxic) and anti-angiogenic effects. Here we aimed to investigate the anti-angiogenic effect of SSTR2 gene transfer into pancreatic cancer cell line PC-3, and the mechanisms involved in this effect. The full-length human SSTR2 complementary DNA was introduced into pancreatic cancer cell line PC-3 by lipofectamine-mediated transfection, and stable expression of SSTR2 was detected by immunohistochemistry and RT-PCR. Athymic mice were separately xenografted with SSTR2-expressing cells (experimental group), vector control and mock control cells. Intratumoral microvessel density (MVD) was assessed by immunohistochemistry. Immunohistochemistry and RT-PCR were used to determine the expression of angiogenic factors vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and matrix metalloproteinase (MMP)-2 in xenograft tumors. MVD was significantly lower in the experimental group (5.16 +/- 1.34) than that in the vector control (16.52 +/- 2.25) and mock control (15.32 +/- 2.53) (P < 0.05). The immunohistochemical assay showed a significant decrease in the expression of VEGF, bFGF and MMP-2 protein in the experimental group compared with the vector control and mock control, considering both the integral optical density and area of staining (P < 0.05). RT-PCR showed a significant reduction of VEGF, bFGF and MMP-2 mRNA expression in the experimental group compared with the vector control and mock control (P < 0.05). Thus, introduction of the SSTR2 gene, the expression of which is frequently lost in human pancreatic adenocarcinoma, exerts its anti-angiogenic effects by down-regulating the expression of the factors, which are involved in tumor angiogenesis and metastasis, suggesting SSTR2 gene transfer as a promising strategy of gene therapy for pancreatic cancer.     

Association between somatostatin receptor 5 gene polymorphisms and pancreatic cancer risk and survival

BACKGROUND:

Somatostatin (SST) inhibited cell proliferation and negatively regulated the release of growth hormones by means of specific receptors (SSTR). Genetic variation in SSTR had been associated with risk of human cancers but had never been investigated in pancreatic cancer.

METHODS:

In this retrospective study the SSTR5 gene in paired tumor and blood samples from 33 pancreatic adenocarcinoma patients using the Sanger method were sequenced. Three single nucleotide polymorphisms (SNPs) in samples from 863 patients with pancreatic ductal adenocarcinoma and 876 healthy controls using the TaqMan method were analyzed. The associations between gene polymorphisms and pancreatic cancer risk and survival were analyzed by multivariate logistic regression and Cox proportional hazard models, respectively.

RESULTS:

No somatic mutations were identified, but 3 nonsynonymous SSTR5 SNPs (P109S, L48M, and P335L) in pancreatic tumors were identified. The SSTR5 P109S variant allele was associated with a 1.62‐fold increased risk of pancreatic cancer (95% confidence interval [CI]: 1.08‐2.43, P = 0.019). Furthermore, the SSTR5 L48M AC variant and smoking had a joint effect on pancreatic cancer risk (p_interaction = 0.035). The odds ratios (95% confidence intervals) were 0.58 (0.34‐0.97), 1.49 (1.18‐1.89), and 2.27 (1.35‐3.83) for the variant genotype alone, smoking alone, and both factors, respectively, compared with no factors. Finally, SSTR5 P335L CC and P109S CC combined were associated with lower overall survival durations in patients with resectable disease.

CONCLUSIONS:

These data suggest that SSTR5 genetic variants play a role in pancreatic cancer development and progression. Cancer 2011. © 2011 American Cancer Society.     

Molecular imaging and treatment of malignant gliomas following adenoviral transfer of the herpes simplex virus-thymidine kinase gene and the somatostatin receptor subtype 2 gene

Patients suffering from malignant glioma have a very poor prognosis. New therapy approaches for gliomas are necessary; these tumors are attractive targets for gene therapy. Our research concentrated on evaluation of the use of the Herpes Simplex Virus-thymidine kinase (tk) enzyme and the somatostatin receptor subtype 2 (sst2). DOTA-Tyr3-octreotate is an analog of somatostatin with high affinity for sst2. It shows rapid internalization in sst2-positive tumor cells in vitro and in vivo. For gene therapy, we used the adenoviral vector Ad5.tk.sstr, which carries the tk gene and the sst2 gene. The aim of our study was to compare uptake of the tk substrate 1-(2-fluoro-2-deoxy-beta-D-ribofuranosyl)-5-[*I]iodouracil (FIRU) labeled with 125I and the somatostatin analog 111In-DOTA-Tyr3-octreotate in several glioma cell lines after infection with Ad5.tk.sstr. Uptake of 125I-FIRU was measured in rat 9L-tk glioma cells without infection with Ad5.tk.sstr. Results showed that the uptake of 125I-FIRU was concentration and time dependent. We also used several rat and human glioma cell lines for infection with Ad5.tk.sstr. Forty-eight hours after infection, uptake studies were performed using 125I-FIRU and 111In-DOTA-Tyr3-octreotate. In all cell lines, the uptake of 125I-FIRU and 111In-DOTA-Tyr3-octreotate increased with increasing multiplicity of infection of virus and showed that the uptake of 111In-DOTA-Tyr3-octreotate was higher than that of 125I-FIRU in all cell lines. We conclude that the sst2 imaging and therapy modality is most promising for glioma gene therapy, either alone or in combination with HSV-tk suicide gene therapy. Therapy can be performed using combinations of DOTA-Tyr3-octreotate radiolabeled with 177Lu or 90Y, 131I-FIRU and/or the prodrug ganciclovir.     

Heparanase expression in primary and metastatic pancreatic cancer.

The human endoglycosidase heparanase (hpa) degrades heparan-sulfate proteoglycans, which constitute prominent components of basement membranes and extracellular matrix. Due to the critical function of hpa in cancer cell invasion and metastasis, we have analyzed the expression of hpa in human primary and metastatic pancreatic cancer as well as in the normal pancreas and in chronic pancreatic inflammation. By real-time quantitative PCR, there was a 7.9- and 30.2-fold increase of hpa mRNA in chronic pancreatitis and pancreatic cancer tissue samples, respectively, in comparison with normal pancreatic tissues. There was a significant correlation between enhanced hpa mRNA expression and shorter postoperative patient survival. hpa mRNA and protein localized in the cancer cells of primary and metastatic pancreatic cancer, with a preferentially higher expression at the primary tumor site. Cultured pancreatic cancer cells transfected with a full-length hpa construct displayed enhanced invasiveness in an invasion chamber assay. These results suggest that hpa overexpression in human pancreatic cancers facilitates cancer cell invasion, thereby enhancing the metastatic potential of the tumors.     

Ad-KDR-CDglyTK双自杀基因系统对荷瘤鼠胃癌体内抑制实验

目的:探讨KDR启动子驱动双自杀基因体系对荷瘤鼠胃癌的体内抑瘤作用.方法:建立胃癌移植瘤动物模型,当肿瘤直径达0.5 cm时,随机分为A组:空白对照,不施加任何处理;B组:注射重组腺病毒AdKDR-CDglyTK与前药5-FC和GCV;C组:仅注射重组腺病毒AdKDR-CDglyTK;D组:仅注射前药5-FC和GCV.治疗过程中绘制肿瘤生长曲线,观察该治疗体系的体内抑瘤效应;通过RT-PCR检测肿瘤组织内融合基因的表达;采用免疫组化行微血管密度检查.结果:接种肿瘤细胞后13d,裸鼠出现右臀区皮下瘤结节.治疗结束后A、B、C、D组间瘤质量差异有统计学意义(F=12 727.42,P=0.000),B组明显缩小.重组腺病毒转基因荷瘤鼠胃癌组织内可检测到CDglyTK融合基因产物的表达.肿瘤组织的MVD值在A、B、C、D组之间差异有统计学意义,F=27.04,P=0.000.结论:KDR启动子驱动双自杀基因体系对裸鼠皮下移植瘤有明显的抑瘤作用,表现为肿瘤的生长抑制和瘤体微血管密度减少等.     

Immunohistochemical determination of five somatostatin receptors in meningioma reveals frequent overexpression of somatostatin receptor subtype sst2A.

Meningioma is one of a variety of human tumors that exhibit a very high density of somatostatin receptors and in many cases show a true positive somatostatin receptor scintigraphy. However, the level of expression of individual somatostatin receptor proteins in meningioma has not been investigated. We have recently developed a panel of somatostatin receptor subtype-specific antibodies that effectively stain formalin-fixed, paraffin-embedded tumor tissue (S. Schulz et al., Clin. Cancer Res., 4: 2047-2052, 1998). In the present study, we have used these antibodies to determine the somatostatin receptor status of 40 randomly selected meningiomas. Immunoreactive staining for all somatostatin receptors was clearly located at the plasma membrane of the tumor cells and completely blocked with antigenic peptide. The vast majority of tumors (29 cases; 70%) were positive for sst2A immunoreactivity; among these, 20 (69%) tumors showed high levels of sst2A immunoreactivity. In contrast, all other somatostatin receptors were only detected sporadically, and none of these cases revealed a particularly strong staining. However, it is uncertain to what extent somatostatin receptor-immunoreactive staining intensity may translate into somatostatin receptor protein expression on the tumor cells. Therefore, in a prospective study, 16 surgically removed meningiomas were collected, and the level of sst2A expression was determined using Western blot analysis. Whereas sst2A was readily detectable as a broad band migrating at Mr 70,000 in 12 (75%) of these tumors, 8 tumors (50%) showed particularly high levels of immunoreactive sst2A receptors. There was an excellent correlation (P < 0.001) between the level of sst2A protein expression detected in Western blots and the sst2A- immunoreactive staining seen in tissue sections. Thus, the frequent overexpression of the sst2A receptor may explain the high tracer uptake often observed in meningioma patients during somatostatin receptor scintigraphy. Moreover, this simple immunohistochemical method could prove useful in identifying those cases of recurrent disease that may possibly respond to therapy with sst2-selective agonists.     

RNA干扰技术抗非小细胞肺癌作用的体内实验研究

Objective  

Lung cancer has emerged as a leading cause of cancer death in the world. Current therapies are ineffective, thus new approaches are needed to improve the therapeutic ratio. RNA interference (RNAi) has shown promise in gene silencing in vitro, the potential of which in developing new methods for the therapy of non-small-cell lung cancer (NSCLC) needs to be further tested in vivo. In this study, chemically synthesized double-stranded RNA (dsRNA) targeting epidermal growth factor receptor (EGFR) was transfected into NSCLC cell line SPC-A1 cells and established the tumor burdened athymic nude mice model to investigate whether dsRNA could induce gene silencing in NSCLC cells in vivo.     

Antitumor effect of adenovirus-mediated Bax gene transfer on p53-sensitive and p53-resistant cancer lines

Antitumor effects of the proapoptotic Bax gene have been evaluated in vitro and in vivo by a binary adenovirus system expressing the human Bax gene. Overexpression of the Bax gene in cultured cell lines from human lung carcinoma results in caspase activation, apoptosis induction, and cell growth suppression. Intratumoral injection of adenovirus vector expressing the Bar gene suppressed growth of human lung cancer xenografts established in nude mice. Histological examination of tumors from mice treated with the Bax gene demonstrated high levels of Bax expression and extensive apoptosis in tumors. In comparison with the treatment by an adenoviral vector expressing human p53, the Bax gene can effectively suppress tumor growth in both p53-sensitive and p53-resistant human lung carcinoma cell lines. Toxicity was not detected in liver and other systems in animals treated intralesionally with the Bax gene. Therefore, our results suggest that the Bar gene may be useful in cancer treatment.     

腺病毒介导的胞嘧啶脱氨酶自杀基因联合IL—2基因疗法的肿瘤治 …

以腺病毒作为载体,将大肠杆菌胞嘧啶脱氨酶基因与小鼠ＩＬ－２基因联合转移,研究其体内抗肿瘤作用及免疫机理。方法小鼠皮下接种黑色素瘤Ｂ１６Ｆ１０细胞后３天,肿瘤局部 注射表达ＩＬ－２的重要腺病毒ＡｄＩＬ－２和表达的ＣＤ的重组腺病毒ＡｄＣＤ,然后连续０天给予５－氟胞嘧啶３００ｍｇ／ｋｇ进行治疗。     

Serum epidermal growth factor receptor and HER2 expression in primary and metastatic breast cancer patients

Background  

Breast tissue expression of the ERBB proto-oncogene family has been extensively studied. It was recently shown that expression of epidermal growth factor receptor (EGFR; c-erbB-1) and epidermal growth factor receptor (HER)2 (c-erbB-2) can be detected in the serum of breast cancer patients. The clinical relevance of this has not been fully established.     

Thymidylate synthase gene expression in primary colorectal cancer and metastatic sites

No Abstract     

Vascular targeting in pancreatic cancer: the novel tubulin-binding agent ZD6126 reveals antitumor activity in primary and metastatic tumor models

ZD6126 is a novel vascular-targeting agent that acts by disrupting the tubulin cytoskeleton of an immature tumor endothelium, leading to an occlusion of tumor blood vessels and a subsequent tumor necrosis. We wanted to evaluate ZD6126 in primary and metastatic tumor models of human pancreatic cancer. Nude mice were injected orthotopically with L3.6pl pancreatic cancer cells. In single and multiple dosing experiments, mice received ZD6126, gemcitabine, a combination of both agents, or no treatment. For the induction of metastatic diseases, additional groups of mice were injected with L3.6pl cells into the spleen. Twenty-four hours after a single-dose treatment, ZD6126 therapy led to an extensive central tumor necrosis, which was not seen after gemcitabine treatment. Multiple dosing of ZD6126 resulted in a significant growth inhibition of primary tumors and a marked reduction of spontaneous liver and lymph node metastases. Experimental metastatic diseases could be significantly controlled by a combination of ZD6126 and gemcitabine, as shown by a reduction of the number and size of established liver metastases. As shown by additional in vitro and in vivo experiments, possible mechanisms involve antivascular activities and subsequent antiproliferative and proapoptotic effects of ZD6126 on tumor cells, whereas direct activities against tumor cells seem unlikely. These data highlight the antitumor and antimetastatic effects of ZD6126 in human pancreatic cancer and reveal benefits of adding ZD6126 to standard gemcitabine therapy.     

Antitumor activity of erlotinib in combination with gemcitabine in in vitro and in vivo models of KRAS-mutated pancreatic cancers

Erlotinib treatment in combination with gemcitabine is a standard therapy for patients with locally advanced pancreatic cancer in many countries, including the US and the EU. Since mutations of the K-ras oncogene (KRAS) occur in approximately 90% of pancreatic cancers, we examined the antitumor activity of erlotinib in combination with gemcitabine in KRAS-mutated pancreatic cancer cell lines, HPAC and Capan-1, which have the KRAS mutation G12D and G12V, respectively. We analyzed the mode of inhibition of in vitro tumor cell proliferation by means of a combination index and found that a combination treatment of erlotinib plus gemcitabine had an additive effect in the two cell lines. We then examined the effect of erlotinib and gemcitabine on the phosphorylation of epidermal growth factor receptor (EGFR). Erlotinib strongly suppressed, while gemcitabine augmented the phosphorylation of EGFR, which was completely blocked by erlotinib in the two cell lines. An in vivo tumor growth inhibition test was then performed using the HPAC tumor xenograft model. The combination therapy of erlotinib and gemcitabine resulted in a significant inhibition of tumor growth compared with erlotinib or gemcitabine monotherapy. To the best of our knowledge, this is the first study to show the combination effect of erlotinib and gemcitabine in vivo using a xenograft model of a KRAS-mutated pancreatic cancer cell line.     

RNA干扰技术抗非小细胞肺癌作用的体内实验研究

目的 探讨体外化学合成表皮牛长因子受体(EGFR)基因序列特异性双链RNA(dsRNA)在体内诱导非小细胞肺癌(NSCLC)细胞出现序列特异性基因沉默的町行性.方法 体外化学合成EGFR序列特异性dsRNA(dsRNA-EGFR),结合脂质体Lipofectamine 2000转染肺腺癌细胞株SPC-A1后,将200 μl细胞悬液接种于裸鼠,建立荷瘤鼠模型,计箅肿瘤抑制率.采用免疫组织化学技术、Western blot技术和实时逆转录聚合酶链反应(real-time RT-PCR),检测肿瘤组织中EGFR蛋白和mRNA的表达水平.结果 dsRNA-EGFR可显著抑制体内肿瘤生长,肿瘤抑制率为75.0%,并可将EGFR蛋白表达水平降低53.6%、mRNA表达水平降低32.3%.结论 dsRNA-EGFR在体内可有效抑制NSCLC细胞中EGFR蛋白和mRNA的表达水平,抑制肿瘤生长.     

腺病毒介导的胞嘧啶脱氨酶自杀基因联合IL-2基因疗法的肿瘤治疗作用及免疫机理分析

目的以腺病毒作为载体，将大肠杆菌胞嘧啶脱氨酶（ＣＤ）基因与小鼠ＩＬ－２基因联合转移，研究其体内抗肿瘤作用及免疫机理。方法小鼠皮下接种黑色素瘤Ｂ１６Ｆ１０细胞后３天，肿瘤局部注射表达ＩＬ－２的重组腺病毒ＡｄＩＬ－２和表达ＣＤ的重组腺病毒ＡｄＣＤ，然后连续１０天给予５－氟胞嘧啶（５－Ｆｃ）３００ｍｇ／ｋｇ进行治疗。结果联合治疗组荷瘤小鼠皮下肿瘤结节的生长明显受到抑制，小鼠存活期明显长于ＡｄＩＬ－２、ＡｄＣＤ／５－Ｆｃ、ＡｄｌａｃＺ／５－Ｆｃ或ＰＢＳ组。经联合治疗后，小鼠脾细胞的ＮＫ活性和ＣＴＬ杀伤活性明显增强；肿瘤瘤体内ＣＤ４、ＣＤ８细胞浸润增加；肿瘤细胞表达Ｈ－２Ｋｂ和Ｂ７－１分子明显增加。结论联合应用自杀基因和ＩＬ－２基因治疗，一方面可以明显抑制荷瘤小鼠肿瘤生长，另一方面可以提高机体对肿瘤细胞免疫应答，增加机体的抗肿瘤作用，是肿瘤基因治疗中一条行之有效的途径。     

Roles for the calcium sensing receptor in primary and metastatic cancer.

AIM: To review the role of the calcium sensing receptor (CASR) in colorectal, breast and parathyroid cancers and related cell lines, and to discuss the effects of CASR in the setting of bone metastases from breast cancer. METHODS: We performed a literature search of the PubMed database of the National Library of Medicine (NLM) to identify articles concerning the CASR's involvement in different cancers. Further relevant papers were obtained from the references of those identified in the original search. RESULTS: Loss of CASR expression is understood to be associated with abnormal differentiation and progression of colorectal carcinoma. It is expressed in both normal and malignant breast tissues and has been implicated in the vicious cycle of bone metastases through its interactions with the parathyroid hormone related peptide (PTHrP). In parathyroid tissue, CASR expression has been linked to proliferation of both parathyroid adenomas and carcinomas. CONCLUSION: Apart from its role in calcium homeostasis, the CASR has many diverse functions in a variety of tissue types throughout the body, and is involved in various signalling pathways relating to cell proliferation and differentiation. CASR has been shown to be involved in the progression and spread of a variety of cancers such as colorectal, breast and parathyroid, and is likely to be the focus of much research to further elucidate its precise role.