抗VEGF/VEGFR靶向肿瘤血管药物的研究进展

研究表明,肿瘤的生长转移和新血管的生成有密切关系,其中血管内皮细胞生长因子(vascular endothelial growth factor,VEGF)及其信号途径在肿瘤血管生成中起关键作用。阻断该途径的任何环节均可有效抑制肿瘤血管的生成,进而抑制肿瘤的生长和转移。近年来,已有多种以VEGF/VEGFR为靶点的抗肿瘤血管生成药物投入临床应用,其中bevacizumab为第一个获批上市的抗肿瘤血管生成药物。继bevacizumab后,一种以基因工程手段获得的人Fc融合蛋白Zaltrap也成功在美国上市,这种杂交分子的药代动力学明显优于单克隆抗体,能更好的遏制肿瘤血管的发生并消退已形成的肿瘤血管。在肿瘤的临床治疗中,Zaltrap比bevacizumab显示出更大的优势。此外,VEGFC/D Trap及小分子酪氨酸激酶抑制剂也能有效抑制肿瘤血管的生成。在此对以VEGF/VEGFR为靶点的抗肿瘤血管生成药物进行综述。     

以VEGF及VEGFR为靶点的抗肿瘤血管生成治疗研究进展

VEGF和VEGFR因其在肿瘤血管生成中的重要作用,已成为肿瘤生物治疗的又一个重要靶点。通过基因治疗,单克隆抗体,小分子抑制物,可溶性受体及导向治疗,或使VEGF和VEGFR表达减少,或阻断其信号转导通路,或耗竭肿瘤细胞产生的VEGF,达到抑制血管新生,切断肿瘤血供,抑制肿瘤生长,发展及转移的目的。     

抗肿瘤血管生成治疗的研究进展及应对策略

抗血管生成疗法作为癌症治疗的重要方法之一,能够显著抑制肿瘤的生长与转移。然而,在临床应用中仍无法避免抗血管生成药物耐药性的产生,且目前对其耐药机制的研究尚不完善,严重阻碍了临床治疗进程。因此,基于抗血管生成药物耐药机制的研究,寻找新的靶点,以及整合新的治疗方案,对于改善肿瘤的临床治疗效果意义重大。基于此,本文主要从血管生成在肿瘤发展中的作用机制、抗血管生成治疗药物的应用现状及其介导的耐药机制、未来的研究策略等方面综述了抗肿瘤血管生成治疗的最新研究进展。     

以VEGF及VEGFR2为靶位的抗肿瘤血管生成主动免疫治疗的研究进展

肿瘤细胞通过刺激新生血管生成来满足对营养及供氧的不断增长的需求,因此,肿瘤组织生长对于新生血管形成的依赖性使得抗血肿瘤管生成已经成为肿瘤学基础研究与临床治疗领域中最吸引人的策略之一.在众多的促血管生成因子中,血管内皮生长因子(VEGF)及其受体VEGFR2(鼠和人中也分别称为Flk-1和KDR)对于与肿瘤生长、转移及复发相关的血管生成是至关重要的.此外,通过打破肿瘤组织自身介导的免疫耐受与逃避,主动免疫治疗已成为一种崭新的抗肿瘤治疗方法.通过将这两种策略联合应用,抗血管生成主动免疫治疗使得更加有效地抑制肿瘤血管生成成为可能.这种免疫治疗与抗血管生成的联合应用有望成为一种有良好前景的研究方案.本文总结了通过打破VEGF/VEGFR2信号通路实现的抗肿瘤血管生成主动免疫治疗方面最新研究进展.本文讨论了旨在抑制血管生成的三种不同形式的抗肿瘤疫苗-细胞疫苗、蛋白质/多肽疫苗及基因/DNA疫苗,以及这一领域未来的研究方向.     

VEGF-C与肿瘤细胞转移

血管内皮生长因子C(VEGF—C)通过与其受体VEGFR2／VEGFR3结合,影响到肿瘤生长、肿瘤外周血管生成、淋巴血管形成、肿瘤表面积,促进肿瘤细胞从原发部位通过血液以及淋巴系统转移到其他器官,是引起肿瘤治疗失败的主要原因之一。阻碍VEGF—C与受体的结合可以降低肿瘤细胞的转移性,为肿瘤治疗提供了1个新的靶点。     

血管内皮生长因子在乳腺癌淋巴道转移中作用的研究进展

血管内皮生长因子(VSGF)是一种重要的血管生成刺激因子,是特异作用于血管内皮细胞、上调血管生成的重要因子,能刺激血管内皮细胞增殖、迁移和诱导血管生成,其家族中VEGF-C、VEGF-D和VEGFR-3在乳腺癌淋巴道转移中起重要作用,可以作为乳腺癌患者的独立预后判断因素.以VEGF为靶点的抗血管化治疗成为治疗乳腺癌的新方法,通过对VEGF信号通路的抑制是目前抗癌治疗研究热点之一.     

VEGF 家族及其在肿瘤生长中作用的研究

血管内皮生长因子(Vascular Endothelial Growth Factor,VEGF)家族是一类多功能的细胞因子,在血管生成和淋巴管生成中具有直接和间接的调控作用,可促进内皮细胞增殖、促进血管生成以及增加血管的通透性。VEGF/VEGFR轴由多重配基和受体质量叠加交错组成,并且受体与配基结合具有专一性,在不同的细胞中具有不同的细胞类型表达和功能.启动VEGF信号通路,触发了一个网状的信号过程,从而促进血管内皮细胞生长、转移和存活。进来研究发现,VEGF的一个重要作用表现为可动员内皮祖细胞从骨髓向远处转移从而形成新生血管,因而有必要设计和发展针对这一途径的抑制因子。随着研究的深入,VEGF促进肿瘤血管生成的作用和与人类癌症的发病机制的关系是确定的,因此,抑制VEGF途径被确认为是一种重要的有效的抗癌模式     

血管内皮生长因子-C与肿瘤细胞转移

血管内皮生长因子(vascular endothelial growth factor,VEGF)C通过与其受体VEGFR2／VEGFR3结合,影响到肿瘤生长、肿瘤外周血管生成、淋巴血管形成、肿瘤表面积,促进肿瘤细胞从原发部位通过血液以及淋巴系统转移到其他器官,是引起肿瘤治疗失败的主要原因之一。阻碍VEGF-C与受体的结合可以降低肿瘤细胞的转移性,为肿瘤治疗提供了一个新的靶点。     

肺癌分子靶向药物研究进展

本文就表皮生长因子受体(EGFR)酪氨酸激酶抑制剂、EGFR单克隆抗体、肿瘤血管生成因子(VEGF)受体抑制荆、内皮抑素以及一些多靶点药物等靶向药物在肺癌中的临床研究和应用进行综述。     

Cell Rep:有效杀伤癌细胞需要两类药物"双剑合璧"

正近日,来自西班牙的科学家们在国际学术期刊CellReports上发表了一项最新研究进展,他们经过深入研究揭示了抗血管生成药物如何发挥抗肿瘤作用以及肿瘤细胞如何抵抗该类药物作用继续存活,同时该研究也为抗血管生成药物的临床应用提供了新的策略。抗血管生成药物能够有效治疗上皮恶性肿瘤,但是这种癌症治疗方法面临的主要问题在于肿瘤会产生获得性抵抗。之前研究发现上皮肿瘤经常在MAPK/PI3K-AKT信号途径上发生基因突变,而该途径常会导致肿瘤细胞走向高耗氧量的糖酵解过程。在这项最新研究中,研究人员发现     

Quantitative Characterization of Cellular Membrane-Receptor Heterogeneity through Statistical and Computational Modeling

Cell population heterogeneity can affect cellular response and is a major factor in drug resistance. However, there are few techniques available to represent and explore how heterogeneity is linked to population response. Recent high-throughput genomic, proteomic, and cellomic approaches offer opportunities for profiling heterogeneity on several scales. We have recently examined heterogeneity in vascular endothelial growth factor receptor (VEGFR) membrane localization in endothelial cells. We and others processed the heterogeneous data through ensemble averaging and integrated the data into computational models of anti-angiogenic drug effects in breast cancer. Here we show that additional modeling insight can be gained when cellular heterogeneity is considered. We present comprehensive statistical and computational methods for analyzing cellomic data sets and integrating them into deterministic models. We present a novel method for optimizing the fit of statistical distributions to heterogeneous data sets to preserve important data and exclude outliers. We compare methods of representing heterogeneous data and show methodology can affect model predictions up to 3.9-fold. We find that VEGF levels, a target for tuning angiogenesis, are more sensitive to VEGFR1 cell surface levels than VEGFR2; updating VEGFR1 levels in the tumor model gave a 64% change in free VEGF levels in the blood compartment, whereas updating VEGFR2 levels gave a 17% change. Furthermore, we find that subpopulations of tumor cells and tumor endothelial cells (tEC) expressing high levels of VEGFR (>35,000 VEGFR/cell) negate anti-VEGF treatments. We show that lowering the VEGFR membrane insertion rate for these subpopulations recovers the anti-angiogenic effect of anti-VEGF treatment, revealing new treatment targets for specific tumor cell subpopulations. This novel method of characterizing heterogeneous distributions shows for the first time how different representations of the same data set lead to different predictions of drug efficacy.     

靶向抑制VEGF在肺癌治疗中的应用前景

血管内皮生长因子（vascular endothelial growth factor,VEGF）是介导肿瘤血管生成最重要因子,与肺癌细胞增殖、转移及预后密切相关。靶向沉默VEGF基因及抑制其受体表达在肺癌治疗中具有光明的应用前景。本文就此进行综述。     

Opposite angiogenic outcome of curcumin against ischemia and Lewis lung cancer models: in silico,in vitro and in vivo studies

The aim of this study was to investigate the angiogenic effects of curcumin on an ischemia and lung cancer model. To induce ischemia combined with lung cancer models, unilateral femoral arteries of C57BL/6 mice were disconnected on one side of the mouse and Lewis lung carcinoma (LLC) cells were xenografted on the opposite side. Angiogenic effects and underlying mechanisms associated with curcumin were investigated. Molecular target(s), signaling cascades and binding affinities were detected by Western blot, two-dimensional gel electrophoresis (2-DE), computer simulations and surface plasmon resonance (SPR) techniques. Curcumin promoted post-ischemic blood recirculation and suppressed lung cancer progression in inbred C57BL/6 mice via regulation of the HIF1α/mTOR/VEGF/VEGFR cascade oppositely. Inflammatory stimulation induced by neutrophil elastase (NE) promoted angiogenesis in lung cancer tissues, but these changes were reversed by curcumin through directly reducing NE secretion and stimulating α1-antitrypsin (α1-AT) and insulin receptor substrate-1 (IRS-1) production. Meanwhile, curcumin dose-dependently influenced endothelial cells (EC) tube formation and chicken embryo chorioallantoic membrane (CAM) neovascularization. Curcumin had opposite effects on blood vessel regeneration under physiological and pathological angiogenesis, which was effected through negative or positive regulation of the HIF1α/mTOR/VEGF/VEGFR cascade. Curcumin had the promise as a new treatment modality for both ischemic conditions and lung cancer simultaneously in the clinic.     

Inhibition of vascular endothelial growth factor expression by TRUE gene silencing

Pathogenic angiogenesis in various diseases including cancer, autoimmune diseases, and age-related macular degeneration is thought to be regressed with anti-angiogenic drugs. TRUE gene silencing is a new technology to eliminate a specific mRNA using synthetic sgRNA and cellular tRNase Z^L. To discover anti-angiogenic sgRNAs, we applied TRUE silencing to the VEGF gene. We examined eight sgRNAs for efficacy in targeting exogenous human VEGF mRNA. Many of them worked efficiently in 293 and HeLa cells. Two of them downregulated the endogenous VEGF gene expression in HeLa cells very efficiently, and the efficacy of these two sgRNAs surpassed that of siRNA extremely.     

Blocking αvβ3 integrin by a recombinant RGD disintegrin impairs VEGF signaling in endothelial cells

Vascular endothelial growth factor (VEGF) and αvβ3 integrin are key molecules that actively participate in tumor angiogenesis and metastasis. Some integrin-blocking molecules are currently under clinical trials for cancer and metastasis treatment. However, the mechanism of action of such inhibitors is not completely understood. We have previously demonstrated the anti-angiogenic and anti-metastatic properties of DisBa-01, a recombinant His-tag RGD-disintegrin from Bothrops alternatus snake venom in some experimental models. DisBa-01 blocks αvβ3 integrin binding to vitronectin and inhibits integrin-mediated downstream signaling cascades and cell migration. Here we add some new information on the mechanism of action of DisBa-01 in the tumor microenvironment. DisBa-01 supports the adhesion of fibroblasts and MDA-MB-231 breast cancer cells but it inhibits the adhesion of these cells to type I collagen under flow in high shear conditions, as a simulation of the blood stream. DisBa-01 does not affect the release of VEGF by fibroblasts or breast cancer cells but it strongly decreases the expression of VEGF mRNA and of its receptors, vascular endothelial growth factor receptors 1 and 2 (VEGFR1 and VEGFR2) in endothelial cells. DisBa-01 at nanomolar concentrations also modulates metalloprotease 2 (MMP-2) and 9 (MMP-9) activity, the latter being decreased in fibroblasts and increased in MDA-MB-231 cells. In conclusion, these results demonstrate that αvβ3 integrin inhibitors may induce distinct effects in the cells of the tumor microenvironment, resulting in blockade of angiogenesis by impairing of VEGF signaling and in inhibition of tumor cell motility.     

An autocrine VEGF/VEGFR2 and p38 signaling loop confers resistance to 4-hydroxytamoxifen in MCF-7 breast cancer cells

Tamoxifen, a partial estrogen receptor antagonist, is part of the standard treatment of both primary and advanced breast cancers. However, significant proportions of breast cancers are either de novo resistant or develop tamoxifen resistance during the course of treatment through mechanisms which have been only partly characterized. We have previously found that high vascular endothelial growth factor (VEGF) or VEGF receptor 2 (VEGFR2) expression and concomitant high p38 mitogen-activated protein kinase activity within breast cancers predict a poor outcome for tamoxifen-treated patients. Here, we have molecularly dissected how VEGF/VEGFR2 and p38 are linked, and contribute to tamoxifen resistance within breast cancer using a MCF-7 BC cell model with different 4-hydroxytamoxifen (4-OHT) responsiveness. We report that MCF-7 breast cancer cell lines with tamoxifen resistance have increased secretion of VEGF and increased signaling through VEGFR2 compared with parental MCF-7 cells. 4-OHT treatment caused the ablation of VEGF secretion in parental MCF-7 cells, whereas in the tamoxifen-resistant subline, a VEGF/VEGFR2 signaling loop was still evident upon treatment. Increased basal levels of total and phosphorylated p38 were observed in tamoxifen-resistant cells. Pharmacologic inhibition of p38 reduced the proliferation of both tamoxifen-responsive and tamoxifen-resistant cells and showed an additive growth-inhibitory effect in combination with 4-OHT. A connection between VEGF/VEGFR2 and p38 signaling was identified by VEGF and VEGFR2 knockdown, which equally reduced both the total and the active forms of p38 in tamoxifen-resistant cells. Taken together, our results suggest that decreased sensitivity to 4-OHT is caused by a death-protecting VEGF/VEGFR2 and p38 growth factor loop in breast cancer cells. Inhibition of these signaling pathways may be beneficial to overcome tamoxifen resistance.     

A systems biology perspective on sVEGFR1: its biological function,pathogenic role and therapeutic use

Angiogenesis is the growth of new capillaries from pre-existent microvasculature. A wide range of pathological conditions, from atherosclerosis to cancer, can be attributed to either excessive or deficient angiogenesis. Central to the physiological regulation of angiogenesis is the vascular endothelial growth factor (VEGF) system – its ligands and receptors (VEGFRs) are thus prime molecular targets of pro-angiogenic and anti-angiogenic therapies. Of growing interest as a prognostic marker and therapeutic target in angiogenesis-dependent diseases is soluble VEGF receptor-1 (sVEGFR1, also known as sFlt-1) – a truncated version of the cell membrane-spanning VEGFR1. For instance, it is known that sVEGFR1 is involved in the endothelial dysfunction characterizing the pregnancy disorder of pre-eclampsia, and sVEGFR1’s therapeutic potential as an anti-angiogenic agent is being evaluated in pre-clinical models of cancer. This mini review begins with an examination of the protein domain structure and biomolecular interactions of sVEGFR1 in relation to the full-length VEGFR1. A synopsis of known and inferred physiological and pathological roles of sVEGFR1 is then given, with emphasis on the utility of computational systems biology models in deciphering the molecular mechanisms by which sVEGFR1’s purported biological functions occur. Finally, we present the need for a systems biology perspective in interpreting circulating VEGF and sVEGFR1 concentrations as surrogate markers of angiogenic status in angiogenesis-dependent diseases.     

Cyperenoic acid,a sesquiterpene derivative from Croton crassifolius,inhibits tumor growth through anti-angiogenesis by attenuating VEGFR2 signal pathway in breast cancer

BackgroundCyperenoic acid, one of the main chemical constituents of the root of Croton crassifolius, exhibited potent anti-angiogenic property on the zebrafish embryo model with little cytotoxicity. Nevertheless, its anti-angiogenic mechanism and anti-tumor effect have not been investigated.PurposeTo investigate the anti-angiogenic mechanisms of cyperenoic acid and evaluate it whether could exert anti-tumor effect by inhibiting angiogenesis.Study designTargeting vascular endothelial growth factor receptor-2 (VEGFR2) pathway to inhibit tumor angiogenesis is a significant strategy for cancer treatment. Initially, the anti-angiogenic effect of cyperenoic acid as well as the mechanisms of the action was studied using both in-vitro and in-vivo methodologies. Then, its anti-tumor effect through anti-angiogenesis by attenuating VEGFR2 signaling pathway was evaluated.MethodsThe in-vitro inhibitory effect of cyperenoic acid on the vascular endothelial growth factor (VEGF)-induced angiogenesis was evaluated using human umbilical vein endothelial cells (HUVECs) model. Moreover, its ex-vivo and in-vivo effects were evaluated using the aortic ring assay and the matrigel plug assay. The influence of the cyperenoic acid on tyrosine phosphorylation of VEGFR2 was studied by western blotting assay and the influence on downstream signaling pathway of VEGFR2 also be detected. Computer-docking simulations were carried out to study the interaction between cyperenoic acid and VEGFR2. Finally, its inhibitory effect on tumor growth was studied using breast cancer xenograft model.ResultsCyperenoic acid possessed little toxicity to HUVECs, but it significantly inhibited VEGF-induced proliferation, invasion, migration and tube formation of HUVECs. Moreover, it inhibited VEGF-induced sprout formation ex vivo and vessel formation in vivo. Further mechanistic study showed that cyperenoic acid could suppress VEGFR2 tyrosine kinase activity and alter its downstream signaling pathways in VEGF-induced HUVECs. In addition, it could form two hydrogen bonds with the ATP binding pocket of the VEGFR2 kinase domain by docking. For breast cancer xenograft model, cyperenoic acid suppressed tumor growth, but no obvious toxic pathologic changes were observed in mice. Besides, it suppressed the phosphorylation of VEGFR2 in tumor, demonstrating its anti-angiogenic ability in vivo partly targeting the VEGFR2.ConlusionCyperenoic acid could exert anti-tumor effect in breast cancer by inhibiting angiogenesis via VEGFR2 signaling pathway.     

VEGF/VEGFR-Targeted Therapy and Immunotherapy in Non-small Cell Lung Cancer: Targeting the Tumor Microenvironment

Non-small cell lung cancer (NSCLC) is the leading cause of death by cancer worldwide. Despite developments in therapeutic approaches for the past few decades, the 5-year survival rate of patients with NSCLC remains low. NSCLC tumor is a complex, heterogeneous microenvironment, comprising blood vessels, cancer cells, immune cells, and stroma cells. Vascular endothelial growth factors (VEGFs) are a major mediator to induce tumor microvasculature and are associated with the progression, recurrence, and metastasis of NSCLC. Current treatment medicines targeting VEGF/VEGF receptor (VEGFR) pathway, including neutralizing antibodies to VEGF or VEGFR and receptor tyrosine kinase inhibitors, have shown good treatment efficacy in patients with NSCLC. VEGF is not only an important angiogenic factor but also an immunomodulator of tumor microenvironment (TME). VEGFs can suppress antigen presentation, stimulate activity of regulatory T (Treg) cells, and tumor-associated macrophages, which in turn promote an immune suppressive microenvironment in NSCLC. The present review focuses on the angiogenic and non-angiogenic functions of VEGF in NSCLC, especially the interaction between VEGF and the cellular components of the TME. Additionally, we discuss recent preclinical and clinical studies to explore VEGF/VEGFR-targeted compounds and immunotherapy as novel approaches targeting the TME for the treatment of NSCLC.