Evaluation of vascular endothelial growth factor blockade and matrix metalloproteinase inhibition as a combination therapy for experimental human pancreatic cancer

Blockade of vascular endothelial growth factor (VEGF) and inhibition of matrix metalloproteinases (MMP) are promising therapies for cancer. This study assessed the effects of a neutralizing anti-VEGF antibody (A4.6.1) and an MMP inhibitor (BB-94) on pancreatic cancer (PaCa) in vivo. Five million cells of two human PaCa cell lines (AsPC-1 and HPAF-2) were injected subcutaneously into nude mice; 1 mm³ fragments of the resulting tumors were implanted into the pancreas of other mice. Animals were randomized into a control group and three treatment groups: A4.6.1 (100 Μg intraperitoneally twice weekly); BB-94 (50 mg/kg every other day); and combination (A4.6.1 plus BB-94). Treatment was started after 3 days and continued for 14 weeks. Tumor volume, local and distant spread (score), and ascites were determined at autopsy. Microvessel density as a parameter of neoangiogenesis was analyzed in CD31-stained tumor sections. Both monotherapies reduced tumor volume (HPAF-2: −89% by A4.6.1 and −75% by BB-94; AsPC-1: −48% by A4.6.1 and −72% by BB-94), spread (HPAF-2: -−76% by A4.6.1 and -58% by BB-94; AsPC-1: −32% by A4.6.1 and −54% by BB-94), and microvessel density (HPAF-2: −75% by A4.6.1 and −30% by BB-94; AsPC-1: −59% by A4.6.1 and −30% by BB-94), resulting in a tendency toward increased survival (HPAF-2: 8 of 8 animals by A4.6.1 or BB-94 vs. 4 of 8; AsPC-1: 3 of 8 by A4.6.1, 4 of 8 by BB-94 vs. 1 of 8). Combination therapy yielded additional effects in the HPAF-2 group with regard to tumor volume (−95%) and development of ascites (0 of 8 vs. 2 of 8 by A4.6.1 or BB-94 vs. 5 of 8 control mice). Both VEGF blockade and MMP inhibition reduce primary tumor size, metastasis, and angiogenesis, thereby increasing survival in experimental pancreatic cancer. Combination treatment results in additive effects in moderately differentiated HPAF-2 tumors. Presented at the Forty-Third Annual Meeting of The Society for Surgery of the Alimentary Tract, San Francisco, California, May 19–22, 2002 (oral presentation). Supported by the R.S. Hirshberg Foundation and the Deutsche Forschungsgemeinschaft (grant HO 1843-1).     

Specific targeting of tumor vasculature by diphtheria toxin-vascular endothelial growth factor fusion protein reduces angiogenesis and growth of pancreatic cancer

Tumor vessels abundantly express receptors for vascular endothelial growth factor (VEGF), a mediator of neoangiogenesis. The aim of this study was to specifically target and damage the vasculature of pancreatic cancer (PaCa) by fusing VEGF to diphtheria toxin (DT), which inhibits protein synthesis of target cells. DT-VEGF fusion protein was produced in vector pGEX-KG and expressed in E. coli SG12036. Human PaCa cell lines (HPAF-2 and AsPC-1) and human endothelial cells (HUVEC) were exposed to DT-VEGF (10 ng/ml – 10,000 ng/ml). Proliferation was assessed after 3 days. One mm3 fragments of subcutaneous PaCa donor tumors were implanted into the pancreas of nude mice that received either DT-VEGF (200 ώg/kg) every other day) or phosphate-buffered saline intraperitoneally for 14 weeks. Tumor volume, metastatic spread, and animal weight were determined at autopsy. Microvessel density was analyzed in CD31 -stained tumor sections. Proliferation of PaCa cells was inhibited at high concentrations of DT-VEGF (≥1000 ng/ml). DT-VEGF decreased the growth of HUVEC at 10 ng/ml. In vivo, DT-VEGF reduced tumor volume (HPAF-2, 76%; AsPC-1, 53%), microvessel density (HPAF-2, 54%; AsPC-1, 62%), and tumor spread (HPAF-2, 89%; AsPC-1, 50%). Survival was increased (HPAF-2, 7/8 vs. 4/8 animals; AsPC-1, 6/8 vs. 1/8 animals). Weight was not influenced by DT-VEGF. The DT-VEGF effect is due to its toxic action on the tumor vasculature rather than to direct inhibition of PaCa cell growth. DT-VEGF therapy was not associated with systemic side effects. Presented at the Forty-Second Annual Meeting of The Society for Surgery of the Alimentary Tract, Atlanta, Georgia, May 20–23, 2001. Supported by the R.S. Hirshberg Foundation and the Deutsche Forschungsgemeinschaft (grant HO 1843–1).     

Suramin Inhibits Not Only Tumor Growth and Metastasis but Also Angiogenesis in Experimental Pancreatic Cancer

Suramin inhibits the proliferation of several human tumors in vivo and in vitro. In this study, the effects of Suramin on proliferation and angiogenesis were investigated in human pancreatic cancer cell lines and in an orthotopic nude mouse model of human pancreatic cancer. The effects of Suramin on proliferation, viability, cell cycle, and apoptosis were studied in five human pancreatic cancer cell lines. Suramin inhibited the proliferation of pancreatic cancer cells in a dose-dependent manner and reduced viability at high concentrations. Cell cycle analysis revealed a decreased S-phase fraction in most cell lines, whereas the apoptotic fraction was not notably different. In vivo treatment with Suramin significantly reduced pancreatic tumor size (MiaPaCa-2, −74%; AsPC-1, −41%; and Capan-1, −49%) and metastatic spread (MiaPaCa-2, −79%; AsPC-1, −34%; and Capan, −38%). As a parameter for angiogenic activity, vascular endothelial growth factor (VEGF) secretion was measured, revealing reduced VEGF concentrations under Suramin treatment in both cell culture medium and ascites. Also, microvessel density quantified in primary tumors was reduced in animals treated with Suramin. Therefore, Suramin inhibits the proliferation of human pancreatic cancer in vitro and in vivo. The therapeutic effects seem to involve cell cycle kinetics and may be in part related to the antiangiogenic action of the drug. Supported by the R.S. Hirshberg Foundation and the Deutsche Forschungsgemeinschaft (Grant HO 1843/2-1 & 1843/3-1).     

Angiogenesis inhibitor TNP-470 reduces human pancreatic cancer growth

In this study we investigated the effects of the angiogenesis inhibitor TNP-470 on human pancreatic cancer cells in vitro and in vivo. The action of TNP-470 on vascular endothelial growth factor (VEGF) was also assessed. In vitro human pancreatic cancer cells (MIAPaCa-2, AsPC-1, and Capan-1), and human umbilical vein endothelial cells (HUVEC) were exposed to increasing concentrations (1 pg/ml to 100 (μg/ml) of TNP-470. Cell proliferation was assessed after 3 days by cell count and MTT assay. In vivo, 5 Χ 10⁶ pancreatic cancer cells were injected subcutaneously into nude mice. Four weeks later, 1 mm³ fragments of the resulting tumors were implanted into the pancreas of other mice. Animals received either TNP-470 (30 mg/kg every other day) or vehicle subcutaneously for 14 weeks. The volume of the primary tumor and metastatic spread were determined at autopsy. Concentrations of VEGF were determined in serum (VEGF_S) and ascites (VEGF_A) by enzyme-linked immunosorbent assay. Microvessel density was analyzed by immunohistochemistry in CD31 -stained tumor sections. In vitro, proliferation and viability of the human pancreatic cancer cell lines were significantly inhibited at high concentrations of TNP-470 (>1 μg/ml). In contrast, TNP-470 effectively decreased the growth of HUVEC at 100 pg/ml. In vivo, tumor volume and dissemination scores were significantly lower in all three pancreatic cancer cell lines. VEGF_S and VEGF_A were not different between treated groups. Treatment with TNP-470 significantly reduced neoangiogenesis in tumors of all three human pancreatic cancer cell lines: MIAPaCa-2 = 74.8 ±7.8/0.74 mm² vs. 24.8 ±3.7/0.74 mm²; AsPC-1 = 65.3 ±5.0/0.74 mm² vs. 26.0 ±3.4/0.74 mm²; and Capan-1 = 82.2 ±5.8/0.74 mm² vs. 26.9 ±2.5/0.74 mm² (P <0.001). However, survival was not statistically different between groups. TNP-470 reduced tumor growth and metastatic spread of pancreatic cancer in vivo. This was probably due to the antiproliferative effect of the agent on endothelial cells rather than to the direct inhibition of pancreatic cancer cell growth. TNP-470 activity was not associated with alteration of VEGF secretion. Supported by the R.S. Hirshberg Foundation and the Deutsche Forschungsgemeinschaft (grant HO 1843-1). Presented at the Forty-First Annual Meeting of The Society for Surgery of the Alimentary Tract, San Diego, Calif., May 21–24, 2000.     

Selective inhibition of endothelin receptor A as an anti-angiogenic and anti-proliferative strategy for human pancreatic cancer

Endothelin-1 (ET-1) plays a major role in tumor proliferation and angiogenesis of various types of cancer acting through endothelin receptors A and B (ETRA and ETRB). The aim of this study was to analyze theET-1/ETRsystem inhumanpancreatic cancer cell linesandto evaluate the effect of a selective endothelin A inhibitor in vitro and in vivo in an orthotopic mouse model. Three different human pancreatic cancer cell lines, MiaPaCa-2, AsPC-1, and Panc-1, were studied. We found that proliferation of human pancreatic carcinoma cells expressing ETRA was significantly reduced with a selective antagonist. Hypoxic conditions led to improved results compared to a normoxic environment (MiaPaCa-2: -53% vs. -18%; AsPC-1: -54% vs. -46%). Proliferation of ETRA negative Panc-1 cells was not decreased. In vivo, the selective ETRA inhibition resulted in reduced angiogenesis as measured by lower microvessel densities (MiaPaCa-2: -47%; AsPC-1: -55%). The blockade of ETRA decreased the volume (MiaPaCa-2: -87%; AsPC-1: -28%) and metastatic spread (MiaPaCa-2: -95.5%; AsPC-1: -27%) of receptorpositive tumors, thereby increasing survival in experimental pancreatic cancer. ETRA blockade did not show an effect on ETRA negative Panc-1 tumors. Therefore, targeting ETRA with a selective antagonist might provide a new approach to reducing proliferation and angiogenesis in human pancreatic cancer. Presented in part at the Forty-Fourth Annual Meeting of The Society for Surgery of the Alimentary Tract, Orlando, Florida, May 18–21, 2003. This work was supported by the R.S. Hirshberg Foundation and the Deutsche Forschungsgemeinschaft (Grant HO 1843/2-1).     

TIMP-1 antisense gene transfection attenuates the invasive potential of pancreatic cancer cells in vitro and inhibits tumor growth in vivo

BACKGROUND: TIMP-1 overexpression decreases the invasive potential of pancreatic cancer cells. By tissue inhibitors of metalloproteinase (TIMP)-1 antisense gene transfection, we expected to produce aggressive pancreatic cancer cells with increased in vitro and in vivo invasive potential. METHODS: PANC-1 cells were transfected with either TIMP-1 gene (CD-1), antisense TIMP-1 gene (AS-3), or empty vector (MB-3). The in vitro cell growth kinetics and invasive potential of each cell line were compared. Total and active matrix metalloproteinase (MMP)-2 levels were determined. Each cell line was then implanted in athymic mice and the resultant tumors were compared for size, weight, MMP activity, and TIMP-1 expression. RESULTS: TIMP-1 modulation did not affect cell proliferation in vitro, but its underexpression and, to a lesser extent, overexpression resulted in attenuated tumor growth in vivo. AS-3 cells showed marked decreases in cell invasion and MMP-2 activity in vitro and in vivo. CONCLUSION: TIMP-1 manipulation, particularly underexpression, greatly reduces the invasive potential of pancreatic cancer by limiting MMP-2 activity without affecting in vitro cell growth. TIMP-1 is a reasonable molecular target in pancreatic cancer therapy.     

Competency-based student self-assessment on a surgery rotation

INTRODUCTION: Vascular endothelial growth factor (VEGF) is an angiogenic factor that increases vascular permeability. VEGF stimulates capillary formation and has mitogenic effects on vascular endothelial cells. The development of malignant ascites causes significant morbidity. We hypothesized that increased levels of VEGF play a role in the development of malignant ascites in patients with pancreatic cancer. METHODS: Athymic mice underwent orthotopic implantation of human pancreatic ductal adenocarcinoma tumors (250,000 cells) into the body of the pancreas. Tumors were allowed to grow for 12 weeks, at which time ascites develops in 50% of mice. Paracentesis was performed on mice with noticeable ascites. Saline lavage was performed in mice with equivalent pancreatic tumor masses without ascites and served as control. Both ascites and tumor masses were harvested for VEGF protein quantitation by ELISA. RESULTS: VEGF protein levels were elevated in malignant ascites by 15-fold compared to control mice with equivalent tumors (N = 6, P < 0.001, t test). VEGF levels were slightly higher in the primary tumor masses harvested from mice without ascites. Mice with ascites also had metastatic nodules throughout the abdominal cavity. CONCLUSIONS: We are reporting for the first time that VEGF levels are increased in the ascites of nude mice with orthotopically transplanted human pancreatic cancers. VEGF increases vascular permeability and allows for extrapancreatic seeding of tumors. Irrespective of primary tumor size, intraperitoneal VEGF levels are increased when ascites and extrapancreatic nodules are present, while a paradoxical decrease is observed in VEGF levels of primary tumors.     

CaSm/gemcitabine chemo-gene therapy leads to prolonged survival in a murine model of pancreatic cancer

BACKGROUND: CaSm, the cancer-associated Sm-like oncogene, is overexpressed in greater than 80% of pancreatic tumors. We previously reported that an adenovirus expressing antisense RNA to CaSm (Ad-alpha CaSm) can decrease pancreatic tumor growth in vivo but is not curative. In the current study we investigated the mechanism of Ad-alpha CaSm's antitumor effect to rationally approach combinatorial therapy for improved efficacy. METHODS: AsPC-1 and Panc-1 human pancreatic cancer cells were treated with Ad-alpha CaSm and examined by MTT assay for in vitro proliferation changes. Flow cytometry determined the effect of CaSm down-regulation on the cell cycle, and then cells treated with Ad-alpha CaSm in combination with cisplatin, etoposide, or gemcitabine chemotherapies were reexamined by MTT assay. SCID-Bg mice bearing subcutaneous AsPC-1 tumors were treated with Ad-alpha CaSm, gemcitabine, or the combination and monitored for tumor growth and survival. RESULTS: Treatment with Ad-alpha CaSm reduced the proliferation of AsPC-1 and Panc-1 cells (59% and 44%, respectively; P <.05). The cell cycle revealed a cytostatic block with decreased G(1) phase and increased DNA content in treated cells. The combination of Ad-alpha CaSm with gemcitabine significantly reduced in vitro proliferation (66% vs 39% and 48% for controls), decreased in vivo AsPC-1 tumor growth by 71% (n = 10), and extended survival time from 57 to 100 days. CONCLUSIONS: Down-regulation of CaSm reduces the growth of pancreatic cancer cells by altering the cell cycle in a cytostatic manner. The combination of Ad-alpha CaSm with gemcitabine is more effective than either agent used separately.     

TIMP-1 overexpression in pancreatic cancer attenuates tumor growth, decreases implantation and metastasis, and inhibits angiogenesis.

BACKGROUND: Matrix metalloproteinases (MMPs) are involved in pancreatic cancer progression. This study was undertaken to determine the effects of overexpression of a natural tissue inhibitor of MMP (TIMP-1) on pancreatic cancer cell growth, metastasis, and angiogenesis. METHODS: A poorly differentiated human pancreatic cancer cell line (PANC-1) underwent gene transfection to overexpress TIMP-1 (CD-1 cells). One million PANC-1 or CD-1 cells were injected into 40 nude mice subcutaneously (N = 20) or orthotopically (N = 20). Mice were sacrificed at 120 days. TIMP-1 overexpression by CD-1 cells was confirmed prior to injection and after necropsy. Immunohistochemical staining was undertaken after necropsy to evaluate tumors for TIMP-1, MMP-2, apoptosis (TUNEL), and angiogenesis (CD-31). RESULTS: Tumors of CD-1 cells were less likely to implant (35% vs 70%, P = 0.05) and grew to smaller size (0.5 g +/- 0.03 vs 1.5 g +/- 0.20, P < 0.001) than tumors of PANC-1 cells. As well, subcutaneous CD-1 tumors appeared later than PANC-1 tumors (45 days +/- 2.0 vs 27 days +/- 2.2, P < 0.001). Orthotopic CD-1 tumors metastasized less often than PANC-1 tumors (20% vs 60%, P < 0.05). MMP-2 expression was similar in PANC-1 and CD-1 tumors, while CD-1 tumors showed increased TIMP-1 expression, increased apoptosis, and decreased angiogenesis relative to PANC-1 tumors. CONCLUSIONS: TIMP-1 overexpression reduces pancreatic cancer cell implantation, growth, metastasis, and angiogenesis, while increasing tumor apoptosis, all without altering MMP-2 production. This study demonstrates the potential role of TIMP-1 as a target in gene therapy for pancreatic cancer.     

VEGF_(121)反义核酸抑制裸鼠胰腺癌移植瘤的增殖及血管生成

目的:探讨VEGF121反义核酸对裸鼠胰腺癌移植瘤的增殖及血管生成的影响,探索通过VEGF反义核酸抑制肿瘤生长.方法:将稳定转染有VEGF反义核酸pcDNA3-ASVEGF121的胰腺癌细胞系Bx-PC-3接种于裸鼠背部皮下.将实验鼠分为实验组、对照组和空白组.定期测定裸鼠移植瘤体积,免疫组织化学法检测裸鼠移植瘤VEGF、Flk-1表达水平.测定裸鼠移植瘤微血管密度.结果:VEGF反义核酸转染BxPC-3细胞后,裸鼠胰腺癌移植瘤生长明显减缓.移植瘤VEGF表达明显受到抑制,Flk-1表达水平上调.裸鼠胰腺癌移植瘤微血管密度明显降低.结论:人反义核酸VEGF121能显著抑制裸鼠胰腺癌移植瘤的增殖,并能抑制裸鼠胰腺癌移植瘤的血管生成.     

VEGF-RII influences the prognosis of pancreatic cancer

OBJECTIVE: To evaluate whether the vascular endothelial growth factor (VEGF) pathway can be used as a target for effective treatment of pancreatic cancer. SUMMARY BACKGROUND DATA: VEGF and its receptors (VEGF-RI and -RII) are the predominant regulators of tumor neoangiogenesis, a key element for tumor growth and progression. However, VEGF receptor expression has been thought to be limited to endothelial cells, limiting the possibility of targeting it for therapy of pancreatic cancer. METHODS: Protein localization and mRNA were studied in pancreatic cancer specimens, normal pancreas, human pancreatic cancer cell lines, and an endothelial cell line. Cell proliferation was determined by [ H] thymidine uptake. Both VEGF receptors were genetically eliminated by antisense technology. The same approach was used in a murine model of pancreatic cancer in a therapeutic approach. RESULTS: VEGF-RI mRNA and VEGF-RII mRNA were expressed in 17 and 15 of 24 pancreatic cancer samples, respectively. VEGF receptors were found not only in blood vessels but also in pancreatic cancer cells. VEGF-RII expression correlated with poor tumor differentiation and was associated with poorer survival, while VEGF-RI expression did not correlate. VEGF treatment led to extensive growth stimulation in six of seven pancreatic cancer cell lines, which was completely inhibited by antisense treatment against VEGF-RII. Liposome-mediated gene transfer in nude mice with pancreatic tumors markedly reduced local tumor growth and decreased metastatic tumor spread. CONCLUSIONS: The VEGF/VEGF-RII pathway regulates angiogenesis and local tumor growth and spread in pancreatic cancer. Genetic targeting of VEGF-RII blocks local growth and metastatic spread of pancreatic cancer cells in vivo and therefore offers a potential new therapeutic option for patients with this disease.     

The cancer-associated Sm-like oncogene: a novel target for the gene therapy of pancreatic cancer

BACKGROUND: The prognosis for pancreatic cancer (PC) remains dismal, providing a clear need for the development of novel therapies. We have previously shown that the cancer-associated Sm-like (CaSm) oncogene is overexpressed in the great majority of pancreatic tumors and is required to maintain the transformed phenotype. The purpose of this study was to determine whether the application of CaSm antisense gene therapy would generate a significant antitumor effect against PC. METHODS: An adenoviral vector (Ad-alphaCaSm) expressing a 900-base pair antisense RNA to CaSm was created. The PC cell lines AsPC-1 and Capan-1 were infected with this vector and examined for changes in in vitro proliferation by using methyl thiazol tetrazolium and soft agar assays. SCID-Bg mice bearing subcutaneous AsPC-1 tumors were treated with Ad-alphaCaSm (1 x 10(9) plaque-forming units) as a single intratumor injection with tumor growth and survival monitored. RESULTS: AsPC-1 and Capan-1 cells showed decreased in vitro proliferation (93%, P =.0041, and 70%, P =. 0038, respectively) and anchorage independent growth (55%, P =.02, and 45%, P =.03, respectively) after treatment. Ad-alphaCaSm reduced in vivo AsPC-1 tumor growth by 40% (n = 10), extending median survival time from 35 to 60 days. CONCLUSIONS: Ad-alphaCaSm demonstrates a significant antitumor effect against pancreatic cancer both in vitro and in vivo. These results support the role of CaSm as a significant gene involved in the neoplastic transformation of pancreatic tumors. Thus CaSm represents a novel gene target in PC and holds potential as a new treatment approach either alone or in combination with existing therapies.     

Effect of the XIAP inhibitor Embelin on TRAIL-induced apoptosis of pancreatic cancer cells

BACKGROUND: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potent inducer of apoptosis in a wide variety of tumor cells, while it has no toxicity for the majority of normal cells.Therefore, TRAIL may be a suitable agent for anticancer therapy. We previously reported that a number of pancreatic cancer cell lines show resistance to TRAIL-induced apoptosis via overexpression of XIAP and FLIP. The present study was conducted to further examine TRAIL-based therapeutic strategies by aiming to restore functional apoptotic pathways in resistant pancreatic cancer cells. METHODS: In various pancreatic cancer cell lines, TRAIL-induced apoptosis was evaluated in the presence or absence of an XIAP-inhibitor (Smac peptide). Second, TRAIL-induced apoptosis was evaluated in TRAIL-resistant AsPC-1 cells with or without FLIP antisense. Third, the combined effect of Smac peptide and FLIP antisense was tested, and the activation of apoptosis-related caspases and poly (ADP-ribose) polymerase was evaluated. Finally, TRAIL-induced apoptosis was evaluated in the presence or absence of FLIP antisense and an XIAP inhibitor (embelin). RESULTS: Smac peptide enhanced TRAIL-induced apoptosis in a dose-dependent manner for several pancreatic cancer cell lines, but showed no effect on TRAIL-resistant AsPC-1 cells. Smac peptide alone had no influence on cell viability. TRAIL-induced apoptosis was restored in TRAIL-resistant AsPC-1 cells by exposure to FLIP antisense, which suppressed the expression of FLIP. The effect of TRAIL was augmented by the combination of FLIP antisense and Smac peptide. Similarly, TRAIL-induced apoptosis was restored by the combination of FLIP antisense and embelin. Activation of apoptotic caspases and cleavage of poly (ADP-ribose) polymerase was observed after sensitization of TRAIL-resistant pancreatic cancer cells. CONCLUSIONS: Pancreatic cancer cells gain resistance to TRAIL-induced apoptosis via expression of the antiapoptotic proteins XIAP and FLIP. Smac peptide and FLIP antisense could restore the apoptotic effect of TRAIL. An XIAP inhibitor, embelin, enhanced the effect of TRAIL in the presence of FLIP antisense. These findings may provide useful information for the development of TRAIL-based therapeutic strategies by restoring functional apoptotic pathways in resistant pancreatic cancer cells. In addition, a low molecular weight XIAP inhibitor like embelin could be a lead compound for the development of effective XIAP inhibitors.     

外周血γδT细胞在胰腺癌裸鼠过继免疫治疗中的作用

目的探讨外周血γδT细胞在胰腺癌裸鼠种植瘤体内过继免疫治疗中的作用。方法用胰腺癌细胞株Cap1注入BALB/c裸鼠皮下建立胰腺癌裸鼠种植瘤模型。裸鼠随机分为3组,每组10只。A组为γδT细胞治疗,B组为αβT细胞治疗,C组给以无血清RPMI1640作为对照。从胰腺癌患者外周血中提取淋巴细胞,体外特异性扩增γδT细胞后注入裸鼠腹腔内,观察种植瘤裸鼠生存时间、肿瘤体积和肿瘤病灶坏死程度。结果A组成瘤率9/10,B、C组均为8/10(P>0.05)。当肿瘤生长到16、37和52d时,A组与B、C组肿瘤体积差别具有统计学意义(P值分别为0.019和0.022)。120d时C组8只种植瘤裸鼠全部死亡,B组有5只死亡,A组有3只死亡,3组之间死亡率差异具有统计学意义(P=0.023);KruskalWallis检验生存时间存在统计学差异(P=0.036)。γδT细胞治疗组中有4只肿瘤病灶出现坏死脱落,B和C组中各有1只肿瘤出现坏死;肿瘤生长到1个月后,B组和C组中裸鼠发生头部、眼眶、尾部、会阴部和对侧腹股沟区转移,A组仅1例发生对侧腹股沟部转移;A组中有1例裸鼠种植瘤脱落消失,而B组和C组均无肿瘤脱落、坏死消失发生。结论外周血γδT细胞对胰腺癌裸鼠种植瘤具有显著的抑瘤作用。     

COX-2特异性抑制剂NS-398对胰腺癌生长及肿瘤血管 生成影响

目的:探讨COX-2特异性抑制剂NS-398对胰腺癌生长的影响及其机制。方法:分别用q RT-PCR与Western blot检测不同人胰腺癌细胞株(Bx PC-3、SWl990、Capan-2、Aspc-1、PANC-1)中COX-2及VEGF表达,并用MTT法检测NS-398在体外对人胰腺癌细胞增殖抑制作用;用体外实验最敏感细胞株建立裸鼠胰腺癌原位移植瘤模型,并随机将荷瘤鼠分为实验组和对照组,分别用NS-398与生理盐水处理,比较两组移植瘤的生长情况,并检测肿瘤组织中COX-2、VEGF蛋白表达及肿瘤微血管密度(MVD)。结果:各胰腺癌细胞中均有COX-2及VEGF表达,NS-398呈时间与浓度依赖性抑制各胰腺癌细胞的体外增殖,其中Bxpc-3细胞COX-2与VEGF表达量最高,且对NS-398最敏感。用Bxpc-3细胞建立原位移植瘤的实验组与对照组裸鼠比较,平均肿瘤体积明显减小(20.215 2 mm~3 vs.204.444 4 mm~3),瘤组织中COX-2与VEGF表达及MVD均明显降低(均P0.05)。结论:NS-398对胰腺癌的生长有抑制作用,其机制可能是通过COX-2途径降低VEGF基因表达从而抑制肿瘤血管生成有关。     

二氢青蒿素对胰腺癌生长的抑制作用

目的 探讨二氢青蒿素在体外、体内对胰腺癌的生长抑制作用.方法 通过MTT法检测二氢青蒿素对胰腺癌细胞株生长的抑制作用,Annexin V-FITC/PI染色流式细胞术检测细胞凋亡;Western blot检测BxPC-3细胞中增殖、凋亡相关蛋白的表达.监测给药后胰腺癌裸鼠移植瘤体积的变化,并通过对肿瘤组织标本Ki-67染色和TUNEL染色检测肿瘤细胞增殖和凋亡情况.结果 MTT结果显示,二氢青蒿素可抑制体外培养的胰腺癌细胞BxPC-3和AsPC-1的增殖,诱导细胞凋亡,且呈剂量依赖性.二氢青蒿素亦可通过抑制增殖和诱导凋亡而抑制胰腺癌的体内生长.Western blot检测BxPC-3细胞中蛋白的表达水平,结果显示二氢青蒿素上调增殖相关蛋白p21WAF1、下调PCNA的表达;上调凋亡相关蛋白Bax、下调Bcl-2的表达,且可增加caspase-9的活化水平.结论 二氢青蒿素在体内外对胰腺癌均有抗肿瘤作用,是胰腺癌治疗的潜在药物.     

The in vivo distribution of human peripheral blood lymphocytes and lymphokine-activated killer cells adoptively transferred in human pancreatic cancer-bearing nude mice

In this study we evaluated human pancreatic cancer xenotransplanted into nude mice as a model suitable for adoptive immunotherapy studies. A pancreatic cancer cell line (MIA PaCa-2) was chosen and its growth in nude mice and sensitivity to lysis by human lymphokine-activated killer (LAK) cells were characterized. This line grew in 96% of the cases when young (4- to 6-week-old) Swiss/NIH nude mice were used. The line was highly sensitive to lysis by LAK cells in a standard chromium-51 release assay (67.8%), similarly to other cell lines known to be highly sensitive, such as K562 (75.6%) and the melanoma cell line SU.102 (53.1%). To assess their in vivo distribution, human peripheral blood lymphocytes (PBLs) and LAK cells were adoptively transferred into nude mice after labeling with indium-111 oxine. The results of this study show that adoptively transferred PBLs and LAK cells localize in this heterologous system as they do in autologous systems. PBLs are taken up mostly by the liver and spleen. The percentage of the administered dose of radioactivity taken up corrected by weight (percent dose per gram tissue) is 64.3 +/- 15.6%d/gm (liver) and 43.5 +/- 9.5%d/gm (spleen). LAK cells are taken up by liver (43.2 +/- 5.3%d/gm) and spleen (28.0 +/- 4.9%d/gm) but also localize significantly more than PBLs in other organs such as lungs (12.9 +/- 3.5%d/gm vs 1.4 +/- 0.3%d/gm, p less than 0.01), kidneys (19.1 +/- 2.1%d/gm vs 6.3 +/- 1.5%d/gm, p less than 0.001), and pancreatic tumors growing in orthotopic position (1.93 +/- 0.36%d/gm vs 0.56 +/- 0.06%d/gm, p less than 0.05). When the nude mice are pretreated with human recombinant tumor necrosis factor, localization of LAK cells compared with PBLs is even further enhanced both in tumors implanted in the pancreas (3.1 +/- 0.5%d/gm vs 0.56 +/- 0.06%d/gm, p less than 0.01) and in the subcutis (12.5 +/- 8.3%d/gm vs 0.95 +/- 0.29%d/gm, p less than 0.001).     

Pancreatic cancer growth is inhibited by blockade of VEGF-RII

BACKGROUND: Angiogenesis is important in the development and progression of pancreatic cancer. Therefore antiangiogenic therapy targeting endothelial cells may represent a promising therapeutic option. The aim of the study was to evaluate antiangiogenic therapy as a potential therapeutic option in pancreatic cancer. METHODS: Replication-deficient retroviruses encoding truncated VEGF-RII were used to block vascular endothelial growth factor (VEGF) signaling. Tumor growth of 3 pancreatic cancer cell lines was assayed in a nude mouse model in which each pancreatic cancer cell line was subcutaneously inoculated together with retrovirus-producing cells. Expression of VEGF was assayed by RT-PCR and by enzyme-linked immunosorbent assay. Oxygen tension in tumors was determined polarographically. RESULTS: All 3 pancreatic cancer cell lines expressed VEGF mRNA, with the highest VEGF secretion seen in MIA PaCa-2 cells. In vivo therapeutic intervention through dominant negative inhibition of VEGF-RII significantly reduced the growth rate of subcutaneous tumors and inhibited tumor neoangiogenesis. Tumor oxygenation, however, was not altered in xenograft tumors treated with dominant negative retroviruses. CONCLUSION: The ligand/receptor system consisting of VEGF and VEGF-RII seems to be of biologic significance in the pathogenesis of pancreatic cancer growth. Therefore therapeutic intervention in this angiogenic system by a retroviral-based gene transfer technology represents a rational and feasible new technique to inhibit tumor growth.     

Efficacy of p120 antisense—Mediated therapy for pancreatic cancer

p120 Antisense oligodeoxynucleotides were used to determine whether they inhibited cell growth of MIA PaCa-2, a highly tumorigenic human pancreatic carcinoma cell line. Growth inhibition assays were determined in vitro by the ability of these oligomers to inhibit DNA synthesis and cell growth. For in vivo studies, nude mice were injected with cells and palpable tumors were found in 16 of 20 animals by day 14. Sixteen animals (8 in each group) were then treated daily (25 mg/kg intraperitoneally) for up to 40 days with nonsense control oligomers or p120 antisense oligomers. p120 Antisense oligomers inhibited the in vitro proliferation of MIA PaCa-2 cells in a dose-dependent manner, and optimal growth inhibition of greater than 90% was achieved at an antisense oligomer concentration of 100 μmol/L. The tumor volume was calculated for antisense- and nonsense-treated animals. Fifteen days after the beginning of treatment, control animals had a significantly greater (P=0.0035) tumor volume (425±244 mm³ above baseline) as compared to p120 antisense-treated animals (166±116 mm³). Seven of the eight control animals formed tumors that had a volume greater than 1200 mm³ 45 days after treatment was begun, whereas only three of eight p120 antisense-treated animals had tumors that were this large. Two of the latter three animals had relatively large, palpable tumors (>150 mm³) prior to treatment. Twenty days after treatment was stopped (day 60), all animals had tumors larger than 1200 mm³. p120 Antisense oligomers were effective for inhibiting in vitro growth of the pancreatic cancer cell line MIA PaCa-2. In preliminary studies, p120 antisense oligomers appeared to inhibit the rate of growth in nude mice; however, no cures were achieved. The most effective response was seen in animals with initial low tumor burden. Supported by grants from the Elsa U. Pardee Foundation and the McDowell Cancer Research Foundation. Presented at the Thirty-Seventh Annual Meeting of The Society for Surgery of the Alimentary Tract, San Francisco, Calif., May 19–22, 1996 (poster presentation).