Brain-derived neurotrophic factor activation of TrkB induces vascular endothelial growth factor expression via hypoxia-inducible factor-1alpha in neuroblastoma cells

The extent of angiogenesis and/or vascular endothelial growth factor (VEGF) expression in neuroblastoma tumors correlates with metastases, N-myc amplification, and poor clinical outcome. Recently, we have shown that insulin-like growth factor-I and serum-derived growth factors stimulate VEGF expression in neuroblastoma cells via induction of hypoxia-inducible factor-1alpha (HIF-1alpha). Because another marker of poor prognosis in neuroblastoma tumors is high expression of brain-derived neurotrophic factor (BDNF) and its tyrosine kinase receptor, TrkB, we sought to evaluate the involvement of BDNF and TrkB in the regulation of VEGF expression. VEGF mRNA levels in neuroblastoma cells cultured in serum-free media increased after 8 to 16 hours in BDNF. BDNF induced increases in VEGF and HIF-1alpha protein, whereas HIF-1beta levels were unaffected. BDNF induced a 2- to 4-fold increase in VEGF promoter activity, which could be abrogated if the hypoxia response element in the VEGF promoter was mutated. Transfection of HIF-1alpha small interfering RNA blocked BDNF-stimulated increases in VEGF promoter activity and VEGF protein expression. The BDNF-stimulated increases in HIF-1alpha and VEGF expression required TrkB tyrosine kinase activity and were completely blocked by inhibitors of phosphatidylinositol 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) pathways. These data indicate that BDNF plays a role in regulating VEGF levels in neuroblastoma cells and that targeted therapies to BDNF/TrkB, PI3K, mTOR signal transduction pathways, and/or HIF-1alpha have the potential to inhibit VEGF expression and limit neuroblastoma tumor growth.     

trans-3,4,5'-Trihydroxystibene inhibits hypoxia-inducible factor 1alpha and vascular endothelial growth factor expression in human ovarian cancer cells.

trans-3,4,5'-Trihydroxystibene (resveratrol) is a natural product commonly found in the human diet and has been shown recently to have anticancer effects on various human cancer cells. However, the molecular basis for its anticancer action remains to be elucidated. In this study, we investigated the effect of resveratrol on hypoxia-inducible factor 1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) expression in human ovarian cancer cells A2780/CP70 and OVCAR-3. We found that although resveratrol did not affect HIF-1alpha mRNA levels, it did dramatically inhibit both basal-level and growth factor-induced HIF-1alpha protein expression in the cells. Resveratrol also greatly inhibited VEGF expression. Mechanistically, we demonstrated that resveratrol inhibited HIF-1alpha and VEGF expression through multiple mechanisms. First, resveratrol inhibited AKT and mitogen-activated protein kinase activation, which played a partial role in the down-regulation of HIF-1alpha expression. Second, resveratrol inhibited insulin-like growth factor 1-induced HIF-1alpha expression through the inhibition of protein translational regulators, including M(r) 70,000 ribosomal protein S6 kinase 1, S6 ribosomal protein, eukaryotic initiation factor 4E-binding protein 1, and eukaryotic initiation factor 4E. Finally, we showed that resveratrol substantially induced HIF-1alpha protein degradation through the proteasome pathway. Our data suggested that resveratrol may inhibit human ovarian cancer progression and angiogenesis by inhibiting HIF-1alpha and VEGF expression and thus provide a novel potential mechanism for the anticancer action of resveratrol.     

肾细胞癌血管内皮生长因子靶向治疗

肾细胞癌的生长、浸润和转移与血管生成密切相关。以血管内皮生长因子（VEGF）通路为靶点,抑制肾细胞癌血管生成,已成为肾细胞癌治疗的研究热点。目前沙利度胺已经进入Ⅱ期临床试验,单克隆抗体和小分子VEGF受体抑制剂进入了Ⅲ期临床试验。VEGF靶向治疗有可能成为肾细胞癌新的辅助治疗标准。     

Coexpression of hypoxia-inducible factors 1alpha and 2alpha, carbonic anhydrase IX, and vascular endothelial growth factor in nasopharyngeal carcinoma and relationship to survival.

PURPOSE: Tumor hypoxia is known to be associated with resistance to chemotherapy, radiotherapy, and poorer survival. Recently, it is shown that hypoxia induces the expression of hypoxia-inducible factor-1alpha and 2alpha (HIF-1alpha and HIF-2alpha), which then up-regulates the expression of downstream genes such as carbonic anhydrase IX (CA IX) and vascular endothelial growth factor (VEGF). EXPERIMENTAL DESIGN: We examined the expression of HIF-1alpha, HIF-2alpha, CA IX, and VEGF by immunohistochemistry in nasopharyngeal carcinoma (NPC) biopsies from 90 consecutive patients recruited between 1994 and 1997 in a randomized controlled trial of chemoradiation in locally advanced NPC and investigated their relationship with survival. RESULTS: HIF-1alpha was expressed in 52 of 90 (58%), HIF-2alpha in 6 of 89 (7%), CA IX in 51 of 90 (57%), and VEGF in 54 of 90 (60%) of tumors. Tumor HIF-1alpha expression correlated significantly with that of CA IX (P = 0.008) and VEGF (P = 0.003). High tumor HIF-1alpha expression was associated with a trend for poor overall survival (P = 0.06). Tumors with a positive hypoxic profile (defined as high expression of both HIF-1alpha and CA9) were associated with worse progression-free survival (P = 0.04). Tumors with both hypoxic and angiogenic profile (defined as high VEGF expression) were associated with a worse progression-free survival (P = 0.0095). CONCLUSION: Overexpression of HIF-1alpha, CA IX, and VEGF is common in NPC, which is probably related to hypoxia up-regulated expression involving a HIF-dependent pathway, and is associated with poor prognosis. Targeting the hypoxia pathway may be useful in the treatment of NPC.     

血管内皮生长因子表达与非小细胞肺癌侵袭、淋巴结转移的关系

 目的 探讨血管内皮生长因子（VEGF）表达与非小细胞肺癌（NSCLC）侵袭、淋巴结转移的相关关系。方法 选取NSCLC组织58例及正常肺支气管黏膜组织25例，采用免疫组化染色法检测VEGF 在各组织中的表达。结果 58例肺癌组织VEGF阳性表达率为43.1 %，明显高于正常肺支气管黏膜组织（14.3 %）（P＜0.01）。VEGF表达与NSCLC组织的分化程度、肿瘤组织类型无关，与淋巴结转移及生存期密切相关（P＜0.05或P＜0.01）。结论 VEGF表达可能是NSCLC发生的一种生物学标志，VEGF的表达检测是判断NSCLC侵袭转移及预后的一个重要参考指标。     

肿瘤细胞系血管内皮生长因子及其受体共表达的研究

背景与目的：血管内皮生长因子（vascular endothelial growth factor,VEGF)旁分泌在肿瘤血管新生中的作用已得到证实,但其自分泌作用尚不清楚。本研究的目的是分析VEGF及其受体（Flt-1和KDR）基因在恶性肿瘤细胞系中的共表达。方法：以看家基因为内标,采用半定量逆转录－聚合酶链反应分析VEGF及其受体基因在30种肿瘤细胞系和4种内皮细胞中的表达水平。结果：在29种肿瘤细胞系和3种内皮细胞系检测到中度以上的VEGF基因表达,而人脐静脉内皮细胞仅有低表达;Flt-1基因表达分别见于50％（6／12）的血液肿瘤,28％（5／18）的实体瘤细胞和2种内皮细胞;仅在16．7％（2／12）的血液肿瘤,33．3％（6／18）实体瘤细胞和2种内皮细胞检测到KDR基因表达;而ECV304细胞并无Flt-1或KDR基因的表达。结论：VEGF基因高表达是肿瘤细胞的重要特征,而VEGF及其受体共表达表明肿瘤细胞系中存在自分泌途径。     

非小细胞肺癌组织中VEGF-C和VEGFR-3的表达及其临床意义

背景与目的:血管内皮生长因子-C(vascularendothelialgrowthfactorC,VEGF-C)和VEGFR-3是促进恶性肿瘤淋巴管形成的重要因子,其表达与恶性肿瘤的淋巴结转移关系密切。本文旨在研究VEGF-C和VEGFR-3蛋白在非小细胞肺癌(non-smallcelllungcancer,NSCLC)组织中的表达及其临床意义。方法:应用免疫组化方法检测77例NSCLC组织中VEGF-C和VEGFR-3表达情况,分析其与肿瘤淋巴管密度(lymphaticvesseldensity,LVD)、肿瘤的大小、癌的组织类型、组织分化程度、淋巴结转移情况、临床复发和术后生存期的关系。结果:77例NSCLC组织中有45例(58%)VEGF-C阳性,32例(42%)VEGFR-3阳性。NSCLC组织中VEGF-C表达与肿瘤组织的分化程度有关(r=-0.32,P=0.018);VEGF-C及VEGFR-3表达与肿瘤的淋巴结转移、LVD、肿瘤大小及术后生存期有关。NSCLC组织中VEGF-C与VEGFR-3表达相关(r=0.23,P=0.045)。结论:VEGF-C和VEGFR-3表达与NSCLC的淋巴结转移、预后相关,它的高表达提示肺癌患者容易出现淋巴结转移和预后不良。     

Elf-1和VEGF在非小细胞肺癌组织中的表达及意义

背景与目的：血管内皮生长因子（vascular endothelial growth factor,VEGF）促进肿瘤血管生成的作用与Ets家族有关,Ets家族中对Elf-1的研究较少。本研究检测非小细胞肺癌（non—small cell lung cancer,NSCLC）组织中转录因子Elf-1和VEGF的表达,探讨其与NSCLC临床病理特征的关系。方法：制备含69例NSCLC组织和6例正常肺组织的组织芯片,采用免疫组化Power Vision-9000法检测Elf-1和VEGF蛋白的表达水平。结果：Elf-1和VEGF在正常肺组织中的表达均为阴性,在NSCLC组织中表达的阳性率分别为72．46％和63．77％,其表达水平与肿瘤细胞分化程度、淋巴结转移、临床分期和术后生存期有关（P〈0．01）。Kaplan—Meier生存分析表明二者的过表达均与患者的生存率有关,阳性表达的患者生存率明显低于阴性者（P〈0．01）。在NSCLC中,Elf-1的表达与VEGF的表达呈正相关（r=0．702,P〈0．01）。结论：Elf-1和VEGF在NSCLC组织中的过表达与肿瘤的分化程度、转移和预后均有关,联合检测二者的表达水平可作为判定NSCLC恶性生物学行为的参考指标。     

Clinical significance of vascular endothelial growth factor C and vascular endothelial growth factor receptor 3 in patients with nonsmall cell lung carcinoma

BACKGROUND: Vascular endothelial growth factor C (VEGF-C) plays an important role in lymphangiogenesis and activates VEGF receptor 3 (VEGFR-3). By contrast, lymphatic spread is an important prognostic factor in patients with nonsmall cell lung carcinoma (NSCLC). The objective of the current study was to determine whether the expression of VEGF-C and VEGFR-3 correlates with clinicopathologic factors and prognosis in patients with primary NSCLC. METHODS: The authors conducted a retrospective review of 180 consecutive patients who underwent complete resection for NSCLC and who did not receive any chemotherapy or radiotherapy prior to surgery. Immunohistochemical staining for VEGF-C and VEGFR-3 was performed. The clinicopathologic implications of VEGF-C and VEGFR-3 expression were analyzed statistically. RESULTS: Of 180 patients with NSCLC, 137 patients (76.1%) were positive for VEGF-C, and 40 patients (22.2%) were positive for VEGFR-3. VEGF-C expression was observed frequently in patients with adenocarcinoma (P = 0.026). For VEGFR-3 expression, significant correlations were demonstrated with age (P = 0.02), gender (P = 0.008), and histologic differentiation in patients with squamous cell carcinoma (P = 0.03). Patients who had positive staining for VEGF-C showed significantly less favorable survival rates compared with patients who had negative staining for VEGF-C (P = 0.003). The survival rates of patients who had positive staining for VEGFR-3 also were significantly lower compared with patients who had negative staining for VEGFR-3 (P < 0.001). Patients who had positive staining for both VEGF-C and VEGFR-3 exhibited the most unfavorable prognoses. Univariate analysis revealed the following prognostic factors: gender (P = 0.03), tumor status (T1,T2 vs. T3; P < 0.01), lymph node status (negative vs. positive; P < 0.01), tumor size (< or = 35 mm vs. > 35 mm; P < 0.01), disease stage (Stage I vs. Stages II and III; P < 0.01), VEGF-C expression (negative vs. positive; P < 0.01), VEGFR-3 expression (negative vs. positive; P < 0.01) and combined VEGF-C and/or VEGFR-3 expression (both positive vs. VEGF-C or VEGFR-3 positive; P < 0.01). Multivariate analysis demonstrated that VEGFR-3 expression was the only independent negative prognostic factor (P < 0.01). CONCLUSIONS: VEGF-C and VEGFR-3 expression may be indicative of survival rates for patients with NSCLC.     

青蒿琥酯对急性单核细胞白血病SHI-1细胞株血管内皮生长因子及其受体表达的影响

 目的　研究青蒿琥酯对急性单核细胞白血病SHI-1细胞株血管内皮生长因子（VEGF）及其受体（VEGFR）的影响。方法　酶联免疫吸附法检测非细胞毒性浓度（5、10、20 ng／ml）青蒿琥酯作用SHI-1细胞后培养上清液VEGF浓度,流式细胞术检测有或无青蒿琥酯作用时,SHI-1细胞表面VEGFR-1及VEGFR-2阳性表达率。结果　培养24、48 h后,无青蒿琥酯作用的 SHI-1细胞培养上清液VEGF质量浓度分别为（980.3±2.2）、（982.4±2.3）pg／ml,VEGFR-1表达率分别为（5.40±3.11）%和（4.45±2.85）%,VEGFR-2表达率分别为（13.90±2.26）%和（13.95±1.96）%。 5、10 、20 ng／ml青蒿琥酯作用24 h后,SHI-1细胞培养上清液VEGF质量浓度分别为（234.6±1.8）、（114.9±1.6）、（108.8±1.5）pg／ml,作用48 h后分别为（62.3±1.7）、（60.9±1.6）、（32.7±1.7）pg／ml,与培养相同时间无青蒿琥酯组相比,VEGF浓度明显下降（均P＜0.05）,且相同浓度青蒿琥酯作用24 h与48 h间差异亦有统计学意义（均P＜0.05）。5、10 、20 ng／ml青蒿琥酯作用24 h,VEGFR-1阳性率分别为（4.30±2.21）%、（4.20±1.37）%和（3.90±1.86）%,作用48 h后分别为（3.80±2.87）%、（3.60±1.73）%和（3.00±1.82）%,相同作用时间不同浓度青蒿琥酯组间及相同浓度作用不同时间组间VEGFR-1阳性率差异均无统计学意义（均P＞0.05）;作用24 h后,SHI-1细胞VEGFR-2阳性率分别为（4.40±1.15）%、（3.10±0.68）%和（1.10±0.72）%,作用48 h后分别为（3.00±1.68）%、（2.20±0.93）%和（0.60±0.92）%,3个不同浓度青蒿琥酯作用相同时间后VEGFR-2表达率降低（均P＜0.05）,相同浓度作用24与48 h间差异均无统计学意义（均P＞0.05）。结论　SHI-1细胞株高分泌VEGF,青蒿琥酯可下调VEGF分泌及VEGFR-2的表达,而对VEGFR-1表达的调节作用不显著。     

Interleukin-18 is a critical factor for vascular endothelial growth factor-enhanced migration in human gastric cancer cell lines

Cell migration and angiogenesis are key steps in tumor metastasis. However, the mechanism of migration regulated by vascular endothelial growth factor (VEGF), a potent regulator of angiogenesis, is not completely understood. This study examined the relationship between VEGF and migration, along with the mechanism involved in the VEGF-regulated migration of human gastric cancer cells. The level of cell migration was increased by recombinant human (rh)VEGF-165 in the VEGF receptor-2-expressing SNU-601 cells. Interleukin (IL)-18 is associated with the malignant progression of tumors. Accordingly, this study examined the effect of IL-18 on the migration of cancer cells in order to identify the factors involved in VEGF-enhanced migration. Inhibiting IL-18 markedly reduced the level of VEGF-enhanced migration, and IL-18 increased cell migration directly through filamentous-actin polymerization and tensin downregulation. It was confirmed that rhVEGF-165 increased IL-18 production significantly. An antioxidant and an extracellular signal-regulated kinase (ERK)1/2-specific inhibitor blocked rhVEGF-165-enhanced IL-18 production. Accordingly, rhVEGF-165 increased the generation of region of interest (ROI) and activated the ERK1/2 pathway. These results suggest that rhVEGF-165 enhances IL-18 production via the generation of ROI and ERK1/2 phosphorylation, which results in the increased migration of gastric cancer cells.