Antiangiogenic Cancer Therapy Research Articles

Alantolactone, a sesquiterpene lactone, inhibits breast cancer growth by antiangiogenic activity via blocking VEGFR2 signaling.

Alantolactone (ALA), a sesquiterpene lactone isolated from several medicinal plants such as Inula helenium, has been identified to have attractive anticancer activity. However, its role in the inhibition of angiogenesis during tumor development remains unclear. In this study, we found ALA can inhibit the proliferation, motility, migration, and tube formation of human umbilical vein endothelial cells. ALA also restrained angiogenesis in chick embryo chorioallantoic membrane and delayed the growth of human MDA-MB-231 breast cancer xenograft in mice through angiogenesis inhibition. Furthermore, ALA suppressed the phosphorylation of vascular endothelial growth factor receptor 2 and its downstream protein kinase including PLCγ1, FAK, Src, and Akt in endothelial cells. Taken together, the antiangiogenic activity of ALA and its molecular mechanism are identified for the first time, indicating that ALA may be a potential drug candidate or lead compound for antiangiogenic cancer therapy.

Dynamic Biomarkers of Response to Antiangiogenic Therapies in Colorectal Cancer: A Review.

Background: Identification of clinical and molecular biomarkers to predict dynamic response or monitor in real-time the efficacy of antiangiogenic therapy represents a major point in the treatment of patients with advanced colorectal cancer. Several stu-dies have been conduced to identify some predictive biomarkers to select patients who will benefit from bevacizumab, the most widely used antiangiogenic monoclonal anti-body.Conclusion: After a decade since the introduction of bevacizumab, no effective predictive biomarkers are available in routine clinical practice. In this review, we summarized the potential candidate dynamic biomarkers that may play a role in this setting.

Isoprenaline/\u03b22-AR activates Plexin-A1/VEGFR2 signals via VEGF secretion in gastric cancer cells to promote tumor angiogenesis

BackgroundThe role of stress signals in regulating gastric cancer initiation and progression is not quite clear. It is known that stress signals modulate multiple processes such as immune function, cell migration and angiogenesis. However, few studies have investigated the mechanisms of how stress signals contribute to gastric cancer angiogenesis.MethodsHere, we used β2-adrenergic receptor (β2-AR) agonist isoprenaline to imitate a stress signal and demonstrated the molecular mechanism underlying stress’s influence on tumor angiogenesis.ResultsWe found that isoprenaline stimulated vascular endothelial growth factor (VEGF) secretion in gastric cancer cells and plexin-A1 expression was induced by human recombinant VEGF165 in both gastric cancer cells and vascular endothelial cells. Furthermore, interfere with plexin-A1 expression in gastric cancer cells influence HUVEC tube formation, migration and tumor growth in vivo.ConclusionsThese findings suggest that isoprenaline stimulate VGEF secretion and subsequently up-regulate the expression of plexin-A1 and VEGFR2 in gastric cancer cells, which form a positive impetus to promote tumor angiogenesis. This study reveals a novel molecular mechanism that a stress signal like isoprenaline may enhance angiogenesis via activating plexin-A1/VEGFR2 signaling pathway in gastric cancer, which may be a potential target in development of an anti-angiogenic therapy for gastric cancer.

Revival of anti-angiogenic therapies in cancer—news on an old therapeutic concept

Revival of anti-angiogenic therapies in cancer—news on an old therapeutic concept

Antiangiogenic therapy in breast cancer.

SummaryBased on a strong rationale for anti-VEGF (vascular endothelial growth factor) treatment in breast cancer and promising preclinical data, great hopes have been placed on the anti-VEGF antibody bevacizumab. Clinical trials, however, reported conflicting results. In metastatic human epidermal growth factor receptor 2(HER2)-negative breast cancer, the addition of bevacizumab to standard chemotherapy improved consistently progression-free survival (PFS), however, without effect on overall survival (OS). In early breast cancer bevacizumab increased the pathologic complete response rate (pCR) after neoadjuvant therapy, but adjuvant trials did not demonstrate an effect on long-term survival. Unfortunately, despite extensive research, there is still no biomarker for bevacizumab efficacy available, making patient selection difficult. This review summarizes all phase III trials investigating efficacy and toxicity of bevacizumab in early, locally advanced and metastatic breast cancer. It recapitulates the main toxicities, gives an overview on biomarker studies and discusses the role and future aspects of antiangiogenic therapy in breast cancer.

Antiangiogenic therapies in colorectal cancer

Angiogenesis is a very important step in the development of cancer. Several antiangiogenic biological agents have been studied during the past two decades for the treatment of colorectal cancer, both in adjuvant and metastatic settings. The first and most intensively studied is bevacizumab, a humanized monoclonal antibody against the vascular endothelial growth factor. Since its approval in 2004, other antiangiogenic agents have been evaluated in clinical trials and some subsequently approved for the treatment of metastatic colorectal cancer such as aflibercept, ramucirumab, and regorafenib. In general, antiangiogenic agents show a modest efficacy in patients with metastatic colorectal cancer but not in the adjuvant setting. Also, there are no predictive biomarkers that could aid in selecting responsive patients. In this review we summarize the results of the completed large clinical trials investigating the efficacy of antiangiogenic therapies in colorectal cancer.

Pharmacodynamic and Pharmacokinetic Markers For Anti-angiogenic Cancer Therapy: Implications for Dosing and Selection of Patients.

Angiogenesis is integral to tumour growth and invasion, and is a key target for cancer therapeutics. However, for many of the licensed indications, only a modest clinical benefit has been observed for both monoclonal antibody and small-molecule tyrosine kinase inhibitor anti-angiogenic therapy. Pre-clinical and clinical studies have attempted to evaluate circulating, imaging, genomic, pharmacokinetic, and pharmacodynamic markers that may aid both the selection of patients for treatment and define dosing. Correct dosing is likely to be critical in the context of vascular normalization to allow better delivery of concomitant anti-cancer therapy and novel imaging techniques hold much promise in the early evaluation of pharmacodynamic response to improve efficacy.

Antisense Oligonucleotides Targeting Y-Box Binding Protein-1 Inhibit Tumor Angiogenesis by Downregulating Bcl-xL-VEGFR2/-Tie Axes.

Y-box binding protein-1 (YB-1), involved in cancer progression and chemoradiation resistance, is overexpressed in not only cancer cells but also tumor blood vessels. In this study, we investigated the potential value of amido-bridged nucleic acid (AmNA)-modified antisense oligonucleotides (ASOs) targeting YB-1 (YB-1 ASOA) as an antiangiogenic cancer therapy. YB-1 ASOA was superior to natural DNA-based ASO or locked nucleic acid (LNA)-modified YB-1 ASO in both knockdown efficiency and safety, the latter assessed by liver function. YB-1 ASOA administered i.v. significantly inhibited YB-1 expression in CD31-positive angiogenic endothelial cells, but not in cancer cells, in the tumors. With regard to the mechanism of its antiangiogenic effects, YB-1 ASOA downregulated both Bcl-xL/VEGFR2 and Bcl-xL/Tie signal axes, which are key regulators of angiogenesis, and induced apoptosis in vascular endothelial cells. In the xenograft tumor model that had low sensitivity to anti-VEGF antibody, YB-1 ASOA significantly suppressed tumor growth; not only VEGFR2 but also Tie2 expression was decreased in tumor vessels. In conclusion, YB-1/Bcl-xL/VEGFR2 and YB-1/Bcl-xL/Tie signal axes play pivotal roles in tumor angiogenesis, and YB-1 ASOA may be feasible as an antiangiogenic therapy for solid tumors.

Targeting CXCR4-dependent immunosuppressive Ly6Clow monocytes improves antiangiogenic therapy in colorectal cancer

Antiangiogenic therapy with antibodies against VEGF (bevacizumab) or VEGFR2 (ramucirumab) has been proven efficacious in colorectal cancer (CRC) patients. However, the improvement in overall survival is modest and only in combination with chemotherapy. Thus, there is an urgent need to identify potential underlying mechanisms of resistance specific to antiangiogenic therapy and develop strategies to overcome them. Here we found that anti-VEGFR2 therapy up-regulates both C-X-C chemokine ligand 12 (CXCL12) and C-X-C chemokine receptor 4 (CXCR4) in orthotopic murine CRC models, including SL4 and CT26. Blockade of CXCR4 signaling significantly enhanced treatment efficacy of anti-VEGFR2 treatment in both CRC models. CXCR4 was predominantly expressed in immunosuppressive innate immune cells, which are recruited to CRCs upon anti-VEGFR2 treatment. Blockade of CXCR4 abrogated the recruitment of these innate immune cells. Importantly, these myeloid cells were mostly Ly6Clow monocytes and not Ly6Chigh monocytes. To selectively deplete individual innate immune cell populations, we targeted key pathways in Ly6Clow monocytes (Cx3cr1-/- mice), Ly6Chigh monocytes (CCR2-/- mice), and neutrophils (anti-Ly6G antibody) in combination with CXCR4 blockade in SL4 CRCs. Depletion of Ly6Clow monocytes or neutrophils improved anti-VEGFR2-induced SL4 tumor growth delay similar to the CXCR4 blockade. In CT26 CRCs, highly resistant to anti-VEGFR2 therapy, CXCR4 blockade enhanced anti-VEGFR2-induced tumor growth delay but specific depletion of Ly6G+ neutrophils did not. The discovery of CXCR4-dependent recruitment of Ly6Clow monocytes in tumors unveiled a heretofore unknown mechanism of resistance to anti-VEGF therapies. Our findings also provide a rapidly translatable strategy to enhance the outcome of anti-VEGF cancer therapies.

Role of Densitometric Criteria in Evaluation of Effectiveness of Antiangiogenic Therapies in Metastatic Colorectal Cancer: An Italian Clinical Experience.

To evaluate the role of densitometric criterion using the Choi Criteria in the assessment of the response to antiangiogenic treatments of metastatic colorectal cancer (mCRC) compared to the RECIST criteria. Fifty-four patients (mean age=50.6 years) affected by advanced colorectal cancer and with hepatic and possibly peritoneal and pulmonary metastases, that can be treated with bevacizumab, were prospectively evaluated by computerized tomography (CT) scan. Metastases were also evaluated by CT in one-dimensional form according to RECIST. Results show that in 58% of analyzed cases, stable disease according to RECIST coincided with stable disease according to the CHOI criteria, whereas in 42% of analyzed cases disease progression according to RECIST corresponded to stable disease or even partial response according to CHOI criteria. By using the densitometric criterion with CHOI criteria, the evaluation of the response to antiangiogenic treatment of mCRC is partially different compared to RECIST criteria.

Novel concepts of antiangiogenic therapies in metastatic renal cell cancer.

SummaryThe era of antiangiogenic drugs targeting the vascular endothelial growth factor (VEGF) signaling pathway has become a mainstay in the treatment of metastatic renal cell carcinoma (mRCC), showing primary responses in 65–70% of patients. Nevertheless, most of those patients progress to angiogenesis inhibitors over time due to different modes of resistance (adaptive and intrinsic). Both in vitro and in vivo analyses provided evidence that PD-L1 upregulation in hypoxia conditions is dependent on hypoxia-inducible factor (HIF)-2alpha and is associated with an overexpression of VEGF. Thus, additional blockade of PD-L1 along with inhibition of angiogenesis pathways seems to represent a novel and innovative treatment concept in mRCC. In this short review, we provide an overview on ongoing phase III trials combining antiangiogenic therapies with checkpoint inhibitors in the first-line setting. Moreover, we critically analyze the impact of recently approved therapeutic antiangiogenic agents and checkpoint inhibitors after progression to first-generation tyrosine kinase inhibitors and their mode of action. In addition, response and resistance hypotheses and biomarkers to antiangiogenic therapy in clinical practice are critically discussed.

Classical VEGF, Notch and Ang signalling in cancer angiogenesis, alternative approaches and future directions (Review).

Angiogenesis is the formation of new vessels starting from pre-existing vasculature. Tumour environment is characterized by ‘aberrant angiogenesis’, whose main features are tortuous and permeable blood vessels, heterogeneous both in their structure and in efficiency of perfusion and very different from normal vessels. Therapeutic strategies targeting the three pathways chiefly involved in tumour angiogenesis, VEGF, Notch and Ang signalling, have been identified to block the vascular supply to the tumour. However, phenomena of toxicity, development of primary and secondary resistance and hypoxia significantly blunted the effects of anti-angiogenic drugs in several tumour types. Thus, different strategies aimed to overcome these problems are imperative. The focus of the present review was some principal ‘alternative’ approaches to classic antiangiogenic therapies, including the cyclooxygenase-2 (COX-2) blockade, the use of oligonucleotide complementary to the miRNA to compete with the mRNA target (antimiRs) and the inhibition of matrix metalloproteinases (MMPs). The role of blood soluble VEGFA as a predictive biomarker during antiangiogenic therapy in gastric, ovarian and colorectal cancer was also examined.

Microenvironmental regulation of tumour angiogenesis

Tumours display considerable variation in the patterning and properties of angiogenic blood vessels, as well as in their responses to anti-angiogenic therapy. Angiogenic programming of neoplastic tissue is a multidimensional process regulated by cancer cells in concert with a variety of tumour-associated stromal cells and their bioactive products, which encompass cytokines and growth factors, the extracellular matrix and secreted microvesicles. In this Review, we discuss the extrinsic regulation of angiogenesis by the tumour microenvironment, highlighting potential vulnerabilities that could be targeted to improve the applicability and reach of anti-angiogenic cancer therapies.

Tumor-targeting templated silica nanoparticles as a dual-drug delivery system for anti-angiogenic ovarian cancer therapy.

The present study indicated the successful construction of a silica nanoparticle (SLN)-based drug delivery system (DDS) for the tumor-targeted co-delivery of two anti-angiogenic drugs, candesartan (CD) and trastuzumab (Tra), for ovarian cancer therapy via different anti-angiogenic mechanisms using hyaluronic acid (HA)/Tra/CD/SLNs. In vitro and in vivo anti-angiogenic assays indicated that CD and Tra exert beneficial functions on suppressing cancer angiogenesis, and exhibited significantly enhanced effects compared with the angiotensin stimulated group (P<0.01). CD and Tra co-delivery also significantly increased the anti-angiogenic effect compared with applying either drug alone (P<0.01). Furthermore, HA on the surface of the DDS was demonstrated to reduce the cytotoxicity of the DDS and also endowed the particles with an advanced tumor-homing property in vitro and in vivo. The present results revealed that HA/Tra/CD/SLNs may be a preferable formulation for anti-angiogenic ovarian cancer therapy.

Morphological analysis of human umbilical vein endothelial cells co-cultured with ovarian cancer cells in 3D: An oncogenic angiogenesis assay.

Antiangiogenic therapy for cancer is a strategy targeted at tumour vasculature, often in combination with conventional cytotoxicity treatments. Animal testing is still the most common method used for evaluating the efficacy of new drugs but tissue-engineered in vitro models are becoming more acceptable for replacing and reducing the use of animals in anti-cancer drug screening. In this study, a 3D co-culture model of human endothelial cells and ovarian cancer cells was developed. This model has the potential to mimic the interactions between endothelial cells and ovarian cancer cells. The feasibility of applying this model in drug testing was explored here. The complex morphology of the co-culture system, which features development of both endothelial tubule-like structures and tumour structures, was analysed quantitatively by an image analysis method. The co-culture morphology integrity was maintained for 10 days and the potential of the model for anti-cancer drug testing was evaluated using Paclitaxel and Cisplatin, two common anti-tumour drugs with different mechanisms of action. Both traditional cell viability assays and quantitative morphological analyses were applied in the drug testing. Cisplatin proved a good example showing the advantages of morphological analysis of the co-culture model when compared with mono-culture of endothelial cells, which did not reveal an inhibitory effect of Cisplatin on the tubule-like endothelial structures. Thus, the tubule areas of the co-culture reflected the anti-angiogenesis potential of Cisplatin. In summary, in vitro cancer models can be developed using a tissue engineering approach to more closely mimic the characteristics of tumours in vivo. Combined with the image analysis technique, this developed 3D co-culture angiogenesis model will provide more reproducible and reliably quantified results and reveal further information of the drug’s effects on both tumour cell growth and tumour angiogenesis.

Cervical cancer cell-derived angiopoietins promote tumor progression.

Metastatic or recurrent cervical cancer has limited treatment options and a high rate of mortality. Although anti-vascular endothelial growth factor drugs have shown great promise as a therapeutic target for treatment of advanced cervical cancer, drug resistance and class-specific side effects negate long-term benefits. The identification of alternative anti-angiogenic factors will be critical for future drug development for advanced or recurrent cervical cancer. In this study, we found that angiopoietins and Tie receptors were highly expressed in cervical cancer cells. Tie-2 expression in tumor cells predicted poorer prognosis. Wound closure assay and Transwell assay showed that upregulated or downregulated Ang-1 and Ang-2 expression promoted or reduced cervical cancer cell lines migration and invasion, respectively. In subcutaneous xenograft models of cervical cancer, downregulation of Ang-1 and Ang-2 attenuated tumor growth. The expression of vimentin and endomucin and microvessel density were all significantly decreased in the siAng-1 group and siAng-2 group relative to the infection control group. Our data support that dual inhibition of Ang-1 and Ang-2 may be an alternative target for anti-angiogenic adjuvant therapy in advanced or recurrent cervical squamous cell cancer.

PROPHYLAXIS AND TREATMENT OF SIDE EFFECTS OF ANTIANGIOGENIC THERAPY IN PATIENTS WITH METASTATIC COLORECTAL CARCINOMA

The review analyzed data from the literature and personal experience of the application of anti-angiogenic therapy in metastatic colorectal cancer. There are presented practical advices on prevention and treatment of the most common side effects of anti-angiogenic therapy.

Malignant pericytes expressing GT198 give rise to tumor cells through angiogenesis.

Angiogenesis promotes tumor development. Understanding the crucial factors regulating tumor angiogenesis may reveal new therapeutic targets. Human GT198 (PSMC3IP or Hop2) is an oncoprotein encoded by a DNA repair gene that is overexpressed in tumor stromal vasculature to stimulate the expression of angiogenic factors. Here we show that pericytes expressing GT198 give rise to tumor cells through angiogenesis. GT198+ pericytes and perivascular cells are commonly present in the stromal compartment of various human solid tumors and rodent xenograft tumor models. In human oral cancer, GT198+ pericytes proliferate into GT198+ tumor cells, which migrate into lymph nodes. Increased GT198 expression is associated with increased lymph node metastasis and decreased progression-free survival in oral cancer patients. In rat brain U-251 glioblastoma xenografts, GT198+ pericytes of human tumor origin encase endothelial cells of rat origin to form mosaic angiogenic blood vessels, and differentiate into pericyte-derived tumor cells. The net effect is continued production of glioblastoma tumor cells from malignant pericytes via angiogenesis. In addition, activation of GT198 induces the expression of VEGF and promotes tube formation in cultured U251 cells. Furthermore, vaccination using GT198 protein as an antigen in mouse xenograft of GL261 glioma delayed tumor growth and prolonged mouse survival. Together, these findings suggest that GT198-expressing malignant pericytes can give rise to tumor cells through angiogenesis, and serve as a potential source of cells for distant metastasis. Hence, the oncoprotein GT198 has the potential to be a new target in anti-angiogenic therapies in human cancer.

Therapeutic targeting of the angiopoietin-TIE pathway.

The endothelial angiopoietin (ANG)-TIE growth factor receptor pathway regulates vascular permeability and pathological vascular remodelling during inflammation, tumour angiogenesis and metastasis. Drugs that target the ANG-TIE pathway are in clinical development for oncological and ophthalmological applications. The aim is to complement current vascular endothelial growth factor (VEGF)-based anti-angiogenic therapies in cancer, wet age-related macular degeneration and macular oedema. The unique function of the ANG-TIE pathway in vascular stabilization also renders this pathway an attractive target in sepsis, organ transplantation, atherosclerosis and vascular complications of diabetes. This Review covers key aspects of the function of the ANG-TIE pathway in vascular disease and describes the recent development of novel therapeutics that target this pathway.

MiRNA-29b suppresses tumor growth through simultaneously inhibiting angiogenesis and tumorigenesis by targeting Akt3

The traditional anti-angiogenic cancer therapy could trigger hypoxia induced factor (HIF) response, leading to “reactive resistance” to chemotherapy. Simultaneously inhibiting both angiogenesis and tumorigenesis would be ideal to overcome this limitation. MicroRNAs (miRNAs) are increasingly explored as new agents for cancer therapy. In the present study, we identified a microRNA (miR-29b) with the ability of simultaneously inhibiting angiogenesis and tumorigenesis. Ectopic expression of miR-29b inhibits HUVECs formed three-dimensional capillary-like tubular structures, tumor cell proliferation, migration and tumor formation. Systemic administration of miR-29b potently suppressed tumor vascularization and cancer cell activity in vivo, resulting in dramatic suppression of tumor growth without toxicity. Moreover, we demonstrated the role of miR-29b in anti-angiogenesis and anti-tumorigenesis is through targeting Akt3 and inducing VEGF and C-myc arrest in breast cancer cells. These findings indicate that this single miRNA could be used as an efficient anti-cancer therapeutic agent to address a critical challenge in cancer therapy.