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.     

VEGF antisense therapy inhibits tumor growth and improves survival in experimental pancreatic cancer

BACKGROUND: Vascular endothelial growth factor (VEGF), a key mediator of angiogenesis, is overexpressed in pancreatic cancer. This study evaluated VEGF production in pancreatic cancer cells and the effect of VEGF antisense on growth and angiogenesis of human pancreatic cancer in a nude mouse model. METHODS: In vitro: VEGF in cell culture supernatant of pancreatic cancer cells (AsPC-1, poorly differentiated; HPAF-2, moderately differentiated) was assessed by enzyme-linked immunosorbent assay. In vivo: A VEGF antisense oligonucleotide (AS-3) was synthesized. One-mm(3) fragments of subcutaneous pancreatic cancer donor tumors were implanted into the pancreas of nude mice also receiving AS-3 (10 mg/kg/day) or vehicle intraperitoneally for 14 weeks. Primary tumor volume, metastasis, and VEGF in plasma and ascites were determined at autopsy. Microvessel density was analyzed in CD31-stained tumors. RESULTS: In vitro: Both pancreatic cancer cell lines secreted VEGF protein (AsPC-1, 4200 +/- 40 pg/10(6) cells; HPAF-2, 8120 +/- 60 pg/10(6) cells). In vivo: AS-3 reduced tumor volume in the HPAF-2 group (860 +/- 140 vs 3830 +/- 590 mm(3)) and metastatic spread in both groups (AsPC-1, 6.5 +/- 0.8 vs 16.7 +/- 0.9 points; HPAF-2, 2.5 +/- 0.2 vs 8.3 +/- 1.5 points). Tumor volume was not different in the AsPC-1 group (1050 +/- 80 vs 1400 +/- 150 mm(3)). Survival was increased in the AsPC-1 group. Plasma levels of VEGF and microvessel density in tumors were significantly reduced in treated animals. Only control animals (50%) developed ascites with high VEGF concentrations. CONCLUSIONS: Human pancreatic cancer cells secrete VEGF at biologically relevant high levels. AS-3 therapy normalizes plasma VEGF and decreases neoangiogenesis, thereby reducing tumor growth and metastasis and improving survival. AS-3-treated animals developed no ascites, suggesting decreased vascular permeability by reducing VEGF expression in pancreatic cancer cells.     

血管内皮生长因子反义RNA对EC9706人食管癌细胞抑制的作用

目的 观察血管内皮生长因子(VEGF)反义RNA对EC9706人食管癌细胞的抑制作用.方法 用脂质体法将反义VEGFcDNA质粒转染至EC9706人食管癌细胞,用噻唑蓝还原法(MTT法)检测EC9706细胞增殖,免疫组化SABC和逆转录-聚合酶链反应(RT-PCR)技术检测VEGF蛋白和VEGF mRNA表达水平.流式细胞术检测细胞凋亡和周期分布.并将转基因EC9706细胞接种于BALB/C裸鼠后肢皮下,4周后观察皮下成瘤情况.结果 被反义VEGFcDNA质粒转染的EC9706食管癌细胞有外源性VEGF反义基因的整合及表达,该细胞VEGF mRNA及蛋白的表达水平降低,但细胞生长增殖能力和增殖周期无明显改变,未发生明显凋亡现象;接种裸鼠28 d后,EC9706-wt组、EC9706-A组及EC9706-E组皮下移植瘤的潜伏期分别为(5.8±2.4)、(12.4±3.6)、(5.3±2.2)d,瘤体重量分别为(2.83 ±0.32)、(0.87±0.14)、(2.62 ±0.68)g,EC9706-A组与其他两组比较差异均有统计学意义(P＜0.05).结论 VEGF反义RNA可抑制EC9706食管癌细胞VEGF表达和裸鼠体内肿瘤生长.     

Non-Angiogenic Functions of VEGF in Breast Cancer

This review advances the hypothesis that the function of vascular endothelial growth factor (VEGF) in breast cancer is not limited to angiogenesis, and that VEGF signaling in breast carcinoma cells is important for the ability of these cells to evade apoptosis and progress towards invasive and metastatic disease. In other terms, VEGF signaling provides a selective advantage for the survival and dissemination of breast carcinoma cells that may be independent of angiogenesis. The key component of this hypothesis is that breast carcinoma cells express specific VEGF receptors and that these receptors respond to autocrine VEGF, resulting in the activation of signaling pathways that impede apoptosis and promote cell migration. A related hypothesis, which is developed in this review, is that the α6β4 integrin, which has been implicated in the survival and motility of breast cancer cells, can stimulate the translation of VEGF mRNA and, consequently, autocrine VEGF signaling. These findings imply that VEGF and VEGF receptor-based therapeutics, in addition to targeting angiogenesis, may also target tumor cells directly.     

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。     

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.     

Expression of the VEGF-receptor Flt-1 in benign, premalignant and malignant prostate tissues

PURPOSE: Vascular endothelial growth factor (VEGF) is one of the most potent regulators of angiogenesis and has been shown to act upon two tyrosine kinase family receptors: c-fms-like tyrosine kinase (Flt-1) and fetal liver kinase. Preliminary reports have emphasized that expression of VEGF receptors is endothelial cell-specific. In this study we verified the localization and distribution of Flt-1 protein and mRNA expression in prostatic adenocarcinoma (CaP) as well as prostate intraepithelial neoplasia (PIN) and benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: 30 selected surgical specimens exhibiting areas with CaP, PIN and BPH histology were evaluated for Flt-1 protein expression by immunohistochemistry. Results were compared with tumor differentiation (Gleason-Score), serum-PSA and clinical followup. Flt-1 synthesis by prostatic carcinoma cell lines, freshly isolated BPH epithelial cells (BPH-EC) and stromal cells was investigated using RT-PCR and intron spanning primer. RESULTS: VEGF receptor Flt-1 specific anti-sera revealed significant staining of prostatic endothelial cells, but the reactivity was not restricted to endothelial cells. BPH-epithelial cells of all specimens reacted significantly with anti-Flt-1. In contrast, tumor cells failed to react with anti-Flt-1 in 56% of the specimens. BPH-EC revealed a uniform anti-Flt-1 reactivity, which was less pronounced and weaker in PIN. Loss of anti-Flt-1 reactivity of prostatic tumor cells did not correlate with preoperative PSA serum levels but increased with tumor dedifferentiation. Interestingly, tumor cells of all CaP specimens with a Gleason score of >8 exhibit no anti-Flt-1 immunoreactivity. Accordingly while PC3, DU145 and LNCaP cells were negative when tested using RT-PCR all BPH tissue derived BPH-EC revealed Flt-1 coding mRNA expression.CONCLUSIONS: Widespread distribution of VEGF receptor Flt-1 in BPH, PIN and prostate cancer specimens suggests that VEGF function in prostate is not restricted to endothelial cells and angiogenesis. However, since the receptor is lost in CaP cells and with tumor dedifferentiation, these yet unknown effects of VEGF on epithelial cells are obviously suppressed with malignant transformation.     

Antisense inhibition of vascular endothelial growth factor in human head and neck squamous cell carcinoma

BACKGROUND: Vascular endothelial growth factor (VEGF) is a potent paracrine angiogenic factor involved in angiogenesis. We determined whether antisense VEGF transfection can suppress angiogenic activity of a human squamous cell carcinoma of the head and neck (SCCHN) cell line. METHODS: Human SCCHN cell lines were screened for VEGF secretion by ELISA. The highest VEGF secreting cell line was transfected with an antisense VEGF vector. Endothelial cell migration assays were performed using the conditioned medium from the transfected clones. Tumorigenicity assays of the transfectants in nude mice were also performed. RESULTS: Antisense VEGF expression exhibited a 20-fold inhibition of VEGF secretion. The addition of conditioned medium from the antisense clones resulted in 50% reduction of endothelial migration. There was no effect on in vivo tumorigenicity. CONCLUSIONS: Antisense VEGF transfection effectively down-regulated VEGF secretion from SCCHN cells that had high VEGF secretion. Targeting VEGF expression may be useful for suppressing angiogenesis in head and neck cancer.     

VEGF反义核酸抑制人胰腺癌细胞的增殖

目的：探讨VEGF121反义核酸对体外培养胰腺癌细胞增殖的影响,以求证明VEGF反义核酸具有抑制肿瘤生长的作用。方法：将稳定转染有VEGF反义核酸pcDNA3-ASVEGF121的胰腺癌细胞系BxPC-3在体外条件下培养,采用ELISA法检测其培养上清液中的VEGF表达水平。检测肿瘤细胞生长曲线,通过克隆形成试验检测肿瘤细胞的体外增值能力。采用Annexin Ⅴ-FITC和PI双标记法以流式细胞仪检测肿瘤细胞凋亡情况。结果：VEGF反义核酸转染BxPC-3细胞后,肿瘤细胞培养液上清VEGF蛋白水平受到明显抑制。生长曲线显示肿瘤细胞生长明显受到抑制,并且肿瘤细胞克隆形成率降低。流式细胞仪检测显示VEGF反义核酸能促进细胞凋亡。结论：人反义VEGF121能显著抑制胰腺癌细胞的VEGF表达,并能抑制肿瘤细胞的生长,促进凋亡。     

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).     

Selective Blockade of Vascular Endothelial Growth Factor Receptor 2 With an Antibody Against Tumor-Derived Vascular Endothelial Growth Factor Controls the Growth of Human Pancreatic Adenocarcinoma Xenografts

Background Vascular endothelial growth factor (VEGF), a key regulator of angiogenesis, is critical for growth of human pancreatic adenocarcinoma. Preclinical studies demonstrate that blockade of VEGF activity can control the growth of pancreatic tumors in mice. In this study, we evaluated the efficacy of 2C3, an antibody that inhibits VEGF receptor 2 activation by human VEGF, to inhibit the growth of human pancreatic adenocarcinoma in mice. Methods Human pancreatic cancer cell lines (MiaPaca-2, Panc-1, and Capan-1) were used to establish xenografts in nu/nu mice. The expression of VEGF and its receptors was determined in each cell line. Proliferation of tumor cells in vitro and tumor growth in vivo in the presence of 2C3 or a control antibody was evaluated. The effect of 2C3 on tumor weight, total vessel density, number of pericyte-associated vessels, and tumor perfusion was determined, and the level of 2C3 in the serum of animals was measured by enzyme-linked immunosorbent assay. Results 2C3 did not affect the proliferation of cells in culture. 2C3 was present and active in the serum of tumor-bearing animals treated with 2C3, and these animals showed a decrease in tumor burden compared with control-treated mice. Therapy with 2C3 resulted in reduced vascular function, measured by a decrease in vessel density and in the percentage of vessels associated with pericytes. Furthermore, tumors derived from Capan-1 cells demonstrated decreased perfusion after treatment with 2C3. Conclusions Blockade of VEGF receptor 2 activation by tumor-derived VEGF decreases tumor vessel function and growth of some human pancreatic adenocarcinoma cell lines in mice. Presented at the 57th Annual Meeting of the Society of Surgical Oncology, New York, New York, March 2004. Dr. Brekken is a paid consultant for, receives research support through a sponsored research agreement with, and has an equity interest in Peregrine Pharmaceuticals Inc., a company that has licensed the exclusive rights to 2C3 from the University of Texas.     

Expression and significance of vascular endothelial growth factor receptor 2 in bladder cancer

PURPOSE: Vascular endothelial growth factor has a critical role in maintaining tumor microvasculature and, as such, is an attractive target for anti-angiogenic therapy. Aberrant expression of VEGF receptors, especially VEGFR2, on epithelial tumor cells allows VEGF to stimulate growth and migration of tumor cells in an autocrine and/or paracrine manner. Therefore, we studied the expression of VEGF and VEGFR2 in bladder cancer, and the relationship to disease characteristics. MATERIALS AND METHODS: Expression of VEGF and VEGFR2 was studied in a cohort of 72 patients with transitional cell cancer of the bladder. Tumor tissues from all patients were analyzed by immunohistochemistry and examined by a pathologist blinded to patient outcome. Patient demographics and disease outcome were correlated with expression of these markers. Bladder cancer cell lines that express VEGFR2 were studied in vitro and in vivo to establish the significance of VEGF/VEGFR2 signaling. RESULTS: Expression of VEGF and VEGFR2 was observed in 58% and 50% of urothelial tumor cells, respectively. VEGF expression failed to correlate with clinical variables. However, VEGFR2 expression correlated with disease stage (coefficient 0.23, p = 0.05). In addition, VEGFR2 expression increased with tumor invasion into the muscle (p <0.01). Experiments with VEGFR2 positive bladder cancer cell lines in vitro demonstrated increased invasion in response to VEGF. In addition, VEGF inhibition augmented the effect of docetaxel in a murine xenograft model of bladder cancer with a significant inhibition in proliferative index and microvascular density, and induction of apoptosis. CONCLUSIONS: Increased VEGFR2 expression correlates with several features that predict progression of urothelial cancer, including disease stage and invasive phenotype. VEGF targeted therapy may enhance the efficacy of standard therapy for bladder cancer.     

血管内皮生长因子C在人乳腺癌细胞株MCF-7及MCF-7/Adr中的表达

目的：检测血管内皮生长因子C（vascular endothelial growth factor C,VEGF-C)mRNA和蛋白在人乳腺癌细胞株MCF－7及其耐药株MCF－7／Adr中的定位，定性表达。方法：根据VEGF－C基因序列，设计合成地高辛标记的特异性寡核苷酸探针，运用原位杂交方法检测培养的细胞株MCF－7和MCF－7／Adr中VEGF－C mRNA的表达；并运用免疫组织化学方法检测了两种细胞中VEGF－C蛋白的表达。结果：原位杂交检测到MCF－7和MCF－7／Adr细胞的胞浆中有阳性蓝色颗粒，免疫组化检测发现两种细胞的胞浆中均有阳性棕黄色颗粒，而阴性对照细胞的胞浆中则均无阳性颗粒。结论：人乳腺癌细胞株MCF－7及其耐药株MCF－7／Adr细胞能够转录VEGF－C mRNA并在其细胞浆中翻译合成相应的蛋白。     

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.     

The Notch signaling pathway is related to neurovascular progression of pancreatic cancer

OBJECTIVE: To analyze the potential role of the Notch signaling pathway in pancreatic cancer angiogenesis and invasion. BACKGROUND: Angiogenesis, pain, and early neuroinvasion are clinical features of pancreatic cancer. Blood vessels and nerves develop together and use common routes through the organism. The Notch pathway (Notch-1/4, Jagged-1/2, Delta-1) appears crucial in this process. The current study analyzed the Notch pathway in pancreatic cancer and characterized its angiogenic and invasive effects. METHODS: Five PaCa cell lines were cultured for the in vitro experiments. Real-time quantitative RT-PCR was done to quantify mRNA expression in 31 human PaCa specimens, and immunohistochemistry was used to localize protein expression within tumor specimens. Activation of the Notch signaling was done by transfection of PaCa cells with a constitutive active Notch-1 mutant (Notch-IC). Overexpression of Jagged and Delta was achieved by transfection of full-length cDNA. Spheroid assays were used to study angiogenesis and ELISAs to measure VEGF, bFGF, and angiogenin expression. Matrigel invasion assays were used to analyze tumor cell invasion. RESULTS: Notch-3 and Notch-4 mRNA were significantly (P < 0.001) overexpressed in PaCa. Immunohistochemistry revealed protein accumulation of Notch-1 as well. All ligands were significantly up-regulated. A positive immunosignal of ligands was seen in nerves, blood vessels, and ductal tumor cells. Transfection of PaCa cells with the constitutive active Notch-IC mutant and with Jagged-1 revealed increased levels for VEGF. Concomitantly, recombinant Jagged-1 increased sprouting of endothelial cells in the spheroid assay. CONCLUSION: The Notch pathway most likely regulates neurovascular development in pancreatic cancer. Activation of this signaling pathway by constitutive Notch-1 mutants and by Jagged-1 causes an angiogenic and invasive tumor phenotype. Specific blockade of Notch signaling may therefore be beneficial for patients with pancreatic cancer.     

Survivin siRNA纳米载体的制备及其对胰腺癌细胞生物学特性的影响

目的：利用纳米技术和基因干扰技术设计并合成携载survivin siRNA的纳米载体,探讨survivins iRNA纳米微粒对人胰腺癌细胞BXPC-3增殖和凋亡的影响。方法：体外培养人胰腺癌BXPC-3细胞,将BXPC-3细胞随机分为4组：生理盐水组、不含基因的纳米微粒组、survivin siRNA组和s urvivins iRNA纳米微粒组。RT-PCR检测survivin mRNA的表达;Wes tern blot法检测s urvivin蛋白的表达;流式细胞仪检测细胞凋亡情况;MTT法检测细胞增殖情况。结果：细胞培养72 h后,survivin siRNA纳米微粒组细胞的survivin mRNA和蛋白表达均低于其他3组（P〈0.05）。survivin siRNA纳米微粒组细胞增殖明显受抑制,生长缓慢,而细胞凋亡率高于其他3组（P〈0.05）。结论：survivin siRNA纳米微粒能够有效减少胰腺癌BXPC-3细胞survivin mRNA和蛋白的表达,提高肿瘤细胞的凋亡,显著抑制BX-PC-3细胞的增殖。     

Interferon-alpha prevents selection of doxorubicin-resistant undifferentiated-androgen-insensitive metastatic human prostate cancer cells

BACKGROUND: We determined whether treatment of metastatic prostate cancer cells with doxorubicin (DOX) and interferon-alpha (IFN-alpha) prevented the emergence of highly undifferentiated tumor cells. METHODS: The state of cell differentiation was determined by analysis of prostate-specific antigen (PSA), E-cadherin, keratin, and vimentin. RESULTS: Human prostate cancer LNCaP-LN3 cells growing in culture as multicell spheroids expressed higher levels of E-cadherin and E-cadherin-associated beta-catenin than LNCaP-LN3 cells growing as monolayers. Treatment of cells with DOX downregulated PSA, E-cadherin, and keratin, and upregulated expression of vimentin and vascular endothelial growth factor (VEGF) mRNA. While treatment of cells with IFN-alpha did not alter gene expression, the addition of IFN-alpha to cultures treated with DOX produced synergistic toxicity and abrogated the changes in gene expression observed in cells treated with DOX alone. CONCLUSIONS: Treatment with IFN-alpha and DOX should be further explored as a therapeutic strategy for androgen-insensitive prostate cancer.     

Short interfering RNA-mediated gene silencing of vascular endothelial growth factor: effects on cellular proliferation in colon cancer cells

HYPOTHESIS: By using short interfering RNA (siRNA) to inhibit the in vitro expression of vascular endothelial growth factor (VEGF) A, we hope to further investigate the presence of an autocrine loop in colon cancer cells. We hypothesize that VEGF inhibition will result in decreased cellular proliferation. DESIGN: Human colon cancer cells were evaluated for the expression of VEGF and VEGF receptor 2 (VEGFR-2). In vitro assessments were then made of the ability of anti-VEGF siRNA to knock down expression of VEGF and the subsequent effect this decreased expression had on colon cancer cell proliferation. SETTING: Surgical oncology research laboratory. INTERVENTIONS: Human colon cancer cells from the RKO cell line were transfected with siRNA targeting the coding region of VEGF. MAIN OUTCOME MEASURES: Enzyme-linked immunosorbent assay, Northern blot analysis, and real-time quantitative polymerase chain reaction were performed to establish the ability of siRNA to decrease VEGF production. Proliferation assays were run on transfected and wild-type cells to establish concomitant decrease in VEGF expression and cellular proliferation. RESULTS: The RKO colon cancer cells expressed both VEGF and VEGFR-2. Those cells transfected with siRNA targeting VEGF showed a 94% knockdown in VEGF expression and a 67% decrease in cellular proliferation. CONCLUSION: Colon cancer cells expressing VEGF and VEGFR-2 may possess an autocrine growth pathway that can be effectively targeted using RNA interference as an antiangiogenic therapy.