Dual targeting of the type 1 insulin-like growth factor receptor and its ligands as an effective antiangiogenic strategy.
ABSTRACT: In pediatric tumor xenograft models, tumor-derived insulin growth factor (IGF-2) results in intrinsic resistance to IGF-IR-targeted antibodies, maintaining continued tumor angiogenesis. We evaluated the antiangiogenic activity of a ligand-binding antibody (MEDI-573) alone or in combination with IGF-I receptor binding antibodies (MAB391, CP01-B02).IGF-stimulated signaling was monitored by increased Akt phosphorylation in sarcoma and human umbilical cord vascular endothelial cells (HUVEC). Angiogenesis was determined in vitro using capillary tube formation in HUVECs and in vivo using a VEGF-stimulated Matrigel assay. Tumor growth delay was examined in 4 sarcoma xenograft models.The IGF ligand-binding antibody MEDI-573 suppressed Akt phosphorylation induced by exogenous IGF-I and IGF-2 in sarcoma cells. Receptor-binding antibodies suppressed IGF-I stimulation of Akt phosphorylation, but IGF-2 circumvented this effect and maintained HUVEC tube formation. MEDI-573 inhibited HUVEC proliferation and tube formation in vitro, but did not inhibit angiogenesis in vivo, probably because MEDI-573 binds murine IGF-I with low affinity. However, in vitro antiangiogenic activity of MEDI-573 was also circumvented by human recombinant IGF-I. The combination of receptor- and ligand-binding antibodies completely suppressed VEGF-stimulated proliferation of HUVECs in the presence of IGF-I and IGF-2, prevented ligand-induced phosphorylation of IGF-IR/IR receptors, and suppressed VEGF/IGF-2-driven angiogenesis in vivo. The combination of CP1-BO2 plus MEDI-573 was significantly superior to therapy with either antibody alone against IGF-I and IGF-2 secreting pediatric sarcoma xenograft models.These results suggest that combination of antibodies targeting IGF receptor and ligands may be an effective therapeutic strategy to block angiogenesis for IGF-driven tumors.
Project description:AIM: To investigate the effects of dauricine (Dau) on insulin-like growth factor-I (IGF-I)-induced hypoxia inducible factor 1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) expression in human breast cancer cells (MCF-7). METHODS: Serum-starved MCF-7 cells were pretreated for 1 h with different concentrations of Dau, followed by incubation with IGF-I for 6 h. HIF-1alpha and VEGF protein expression levels were analyzed by Western blotting and ELISA, respectively. HIF-1alpha and VEGF mRNA levels were determined by real-time PCR. In vitro angiogenesis was observed via the human umbilical vein endothelial cell (HUVEC) tube formation assay. An in vitro invasion assay on HUVECs was performed. RESULTS: Dau significantly inhibited IGF-I-induced HIF-1alpha protein expression but had no effect on HIF-1alpha mRNA expression. However, Dau remarkably suppressed VEGF expression at both protein and mRNA levels in response to IGF-I. Mechanistically, Dau suppressed IGF-I-induced HIF-1alpha and VEGF protein expression mainly by blocking the activation of PI-3K/AKT/mTOR signaling pathway. In addition, Dau reduced IGF-I-induced HIF-1alpha protein accumulation by inhibiting its synthesis as well as by promoting its degradation. Functionally, Dau inhibited angiogenesis in vitro. Moreover, Dau had a direct effect on IGF-I-induced invasion of HUVECs. CONCLUSION: Dau inhibits human breast cancer angiogenesis by suppressing HIF-1alpha protein accumulation and VEGF expression, which may provide a novel potential mechanism for the anticancer activities of Dau in human breast cancer.
Project description:This phase I, multicenter, open-label, single-arm, dose-escalation, and dose-expansion study evaluated the safety, tolerability, and antitumor activity of MEDI-573 in adults with advanced solid tumors refractory to standard therapy or for which no standard therapy exists.Patients received MEDI-573 in 1 of 5 cohorts (0.5, 1.5, 5, 10, or 15 mg/kg) dosed weekly or 1 of 2 cohorts (30 or 45 mg/kg) dosed every 3 weeks. Primary end points included the MEDI-573 safety profile, maximum tolerated dose (MTD), and optimal biologic dose (OBD). Secondary end points included MEDI-573 pharmacokinetics (PK), pharmacodynamics, immunogenicity, and antitumor activity.In total, 43 patients (20 with urothelial cancer) received MEDI-573. No dose-limiting toxicities were identified, and only 1 patient experienced hyperglycemia related to treatment. Elevations in levels of insulin and/or growth hormone were not observed. Adverse events observed in >10% of patients included fatigue, anorexia, nausea, diarrhea, and anemia. PK evaluation demonstrated that levels of MEDI-573 increased with dose at all dose levels tested. At doses >5 mg/kg, circulating levels of insulin-like growth factor (IGF)-I and IGFII were fully suppressed. Of 39 patients evaluable for response, none experienced partial or complete response and 13 had stable disease as best response.The MTD of MEDI-573 was not reached. The OBD was 5 mg/kg weekly or 30 or 45 mg/kg every 3 weeks. MEDI-573 showed preliminary antitumor activity in a heavily pretreated population and had a favorable tolerability profile, with no notable perturbations in metabolic homeostasis.
Project description:Angiogenesis is an effective target in cancer control. The antiangiogenic efficacy and associated mechanisms of acacetin, a plant flavone, are poorly known. In the present study, acacetin inhibited growth and survival (up to 92%; P < 0.001), and capillary-like tube formation on Matrigel (up to 98%; P < 0.001) by human umbilical vein endothelial cells (HUVEC) in regular condition, as well as VEGF-induced and tumor cells conditioned medium-stimulated growth conditions. It caused retraction and disintegration of preformed capillary networks (up to 91%; P < 0.001). HUVEC migration and invasion were suppressed by 68% to 100% (P < 0.001). Acacetin inhibited Stat-1 (Tyr701) and Stat-3 (Tyr705) phosphorylation, and downregulated proangiogenic factors including VEGF, endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), matrix metalloproteinase-2 (MMP-2), and basic fibroblast growth factor (bFGF) in HUVEC. It also suppressed nuclear localization of pStat-3 (Tyr705). Acacetin strongly inhibited capillary sprouting and networking from rat aortic rings and fertilized chicken egg chorioallantoic membrane (CAM; ?71%; P < 0.001). Furthermore, it suppressed angiogenesis in Matrigel plugs implanted in Swiss albino mice. Acacetin also inhibited tyrosine phosphorylation of Stat-1 and -3, and expression of VEGF in cancer cells. Overall, acacetin inhibits Stat signaling and suppresses angiogenesis in vitro, ex vivo, and in vivo, and therefore, it could be a potential agent to inhibit tumor angiogenesis and growth.
Project description:Angiogenesis, the process by which new blood vessels are recruited to existing ones, is essential for tumor development. Insulin-like growth factor (IGF) binding protein-3 (IGFBP-3), which modulates bioavailability of IGF, has been studied for its potential role in angiogenesis during tissue regeneration and cancer development. In this study, we assessed the role of IGFBP-3 in tumor angiogenesis in head and neck squamous cell carcinoma (HNSCC) and human umbilical vein endothelial cells (HUVECs) using adenoviral (Ad-BP3) and recombinant (rBP3) IGFBP-3. Using an in vivo orthotopic tongue tumor model, we confirmed that both Ad-BP3 and rBP3 suppress the growth of UMSCC38 HNSCC cells in vivo. Ad-BP3 inhibited vascularization in tongue tumors and chorio-allantoic membrane, and suppressed angiogenesis-stimulating activities in UMSCC38 cells. In HUVECs, Ad-BP3 decreased migration, invasion, and tube formation. rBP3 also suppressed production of vascular endothelial growth factor (VEGF) in HUVECs and UMSCC38 cells. IGFBP-3-GGG, a mutant IGFBP-3 with loss of IGF binding capacity, suppressed VEGF production. In addition, we found that IGFBP-3 suppressed VEGF expression, even in mouse embryonic fibroblasts from an IGF-1R-null mouse. Finally, we demonstrated that IGFBP-3-GGG inhibits tumor angiogenesis and growth to the same degree as wild-type IGFBP-3. Taken together, these results support the hypothesis that IGFBP-3 has anti-angiogenic activity in HNSCC, at least in part due to IGF-independent suppression of VEGF production from vascular endothelial cells and cancer cells.
Project description:Angiogenesis contributes to coronary heart disease, immune disorders and numerous malignancies. VEGF-A and its receptors (VEGFRs) play a pivotal role in regulating angiogenesis. In an effort to discover more effective inhibitors of tumour angiogenesis, we have analysed the actions of a novel anthraquinone derivative, PPemd26, and explored its anti-angiogenic mechanisms.The effects of PPemd26 were evaluated in vitro using HUVEC cultures to assess proliferation, migration, invasion and tube formation. Immunoblotting was used to analyse phosphorylation of signalling kinases. Effects in vivo were assayed using Matrigel plug and xenograft mouse models.PPemd26 significantly inhibited VEGF-A-induced proliferation, migration, invasion and tube formation of HUVECs. PPemd26 also attenuated VEGF-A-induced microvessel sprouting from rat aortic rings ex vivo and suppressed formation of new blood vessels in implanted Matrigel plugs in models of angiogenesis in vivo. In addition, PPemd26 inhibited VEGF-A-induced phosphorylation of VEGFR2 and its downstream protein kinases including Akt, focal adhesion kinase, ERK and Src. Furthermore, systemic administration of PPemd26 suppressed the growth of s.c. xenografts of human colon carcinoma in vivo. Histochemical analysis of the xenografts revealed a marked reduction in stainingfor the vascular marker CD31 and proliferation marker Ki-67.This study provides evidence that PPemd26 suppressed tumour angiogenesis through inhibiting VEGFR2 signalling pathways, suggesting that PPemd26 is a potential drug candidate for developing anti-angiogenic agents for the treatment of cancer and angiogenesis-related diseases.
Project description:Corneal neovascularization is a sight-threatening condition caused by angiogenesis in the normally avascular cornea. Neovascularization of the cornea is often associated with an inflammatory response, thus targeting VEGF-A alone yields only a limited efficacy. The NF-?B signaling pathway plays important roles in inflammation and angiogenesis. Here, we study consequences of the inhibition of NF-?B activation through selective blockade of the IKK complex I?B kinase ? (IKK2) using the compound IMD0354, focusing on the effects of inflammation and pathological angiogenesis in the cornea. In vitro, IMD0354 treatment diminished HUVEC migration and tube formation without an increase in cell death and arrested rat aortic ring sprouting. In HUVEC, the IMD0354 treatment caused a dose-dependent reduction in VEGF-A expression, suppressed TNF?-stimulated expression of chemokines CCL2 and CXCL5, and diminished actin filament fibers and cell filopodia formation. In developing zebrafish embryos, IMD0354 treatment reduced expression of Vegf-a and disrupted retinal angiogenesis. In inflammation-induced angiogenesis in the rat cornea, systemic selective IKK2 inhibition decreased inflammatory cell invasion, suppressed CCL2, CXCL5, Cxcr2, and TNF-? expression and exhibited anti-angiogenic effects such as reduced limbal vessel dilation, reduced VEGF-A expression and reduced angiogenic sprouting, without noticeable toxic effect. In summary, targeting NF-?B by selective IKK2 inhibition dampened the inflammatory and angiogenic responses in vivo by modulating the endothelial cell expression profile and motility, thus indicating an important role of NF-?B signaling in the development of pathologic corneal neovascularization.
Project description:The IGF1R signaling pathway is a complex and tightly regulated network that is critical for cell proliferation, growth, and survival. IGF1R is a potential therapeutic target for patients with many different malignancies. This brief review summarizes the results of clinical trials targeting the IGF1R pathway in patients with breast cancer, sarcoma, and non-small cell lung cancer (NSCLC). Therapeutic agents discussed include both monoclonal antibodies to IGF1R (dalotuzumab, figitumumab, cixutumumab, ganitumab, R1507, AVE1642) and newer IGF1R pathway targeting strategies, including monoclonal antibodies to IGF1 and IGF2 (MEDI-573 and BI 836845) and a small-molecule tyrosine kinase inhibitor of IGF1R (linsitinib). The pullback of trials in patients with breast cancer and NSCLC based on several large negative trials is noted and contrasted with the sustained success of IGF1R inhibitor monotherapy in a subset of patients with sarcoma. Several different biomarkers have been examined in these trials with varying levels of success, including tumor expression of IGF1R and its pathway components, serum IGF ligand levels, alternate pathway activation, and specific molecular signatures of IGF1R pathway dependence. However, there remains a critical need to define predictive biomarkers in order to identify patients who may benefit from IGF1R-directed therapies. Ongoing research focuses on uncovering such biomarkers and elucidating mechanisms of resistance, as this therapeutic target is currently being analyzed from the bedside to bench.
Project description:Malignant gliomas are one of the most devastating and incurable tumors. Sustained excessive angiogenesis by glioma cells is the major reason for their uncontrolled growth and resistance toward conventional therapies resulting in high mortality. Therefore, targeting angiogenesis should be a logical strategy to prevent or control glioma cell growth. Earlier studies have shown that Asiatic Acid (AsA), a pentacyclic triterpenoid, is effective against glioma and other cancer cells; however, its efficacy against angiogenesis remains unknown. In the present study, we examined the anti-angiogenic efficacy of AsA using human umbilical vein endothelial cells (HUVEC) and human brain microvascular endothelial cells (HBMEC). Our results showed that AsA (5-20 µM) inhibits HUVEC growth and induces apoptotic cell death by activating caspases (3 and 9) and modulating the expression of apoptosis regulators Bad, survivin and pAkt-ser473. Further, AsA showed a dose-dependent inhibition of HUVEC migration, invasion and capillary tube formation, and disintegrated preformed capillary network. AsA also inhibited the VEGF-stimulated growth and capillary tube formation by HUVEC and HBMEC. Next, we analyzed the angiogenic potential of conditioned media collected from human glioma LN18 and U87-MG cells treated with either DMSO (control conditioned media, CCM) or AsA 20 µM (AsA20 conditioned media, AsA20CM). CCM from glioma cells significantly enhanced the capillary tube formation in both HUVEC and HBMEC, while capillary tube formation in both endothelial cell lines was greatly compromised in the presence of AsA20CM. Consistent with these results, VEGF expression was lesser in AsA20CM compared to CCM, and indeed AsA strongly inhibited VEGF level (both cellular and secreted) in glioma cells. AsA also showed dose-dependent anti-angiogenic efficacy in Matrigel plug assay, and inhibited the glioma cells potential to attract HUVEC/HBMEC. Overall, the present study clearly showed the strong anti-angiogenic potential of AsA and suggests its usefulness against malignant gliomas.
Project description:Hamacanthins, bis (indole) alkaloids, are found in a few marine sponges, including Spongosorites sp. Hamacanthins have been shown to possess cytotoxic, antibacterial and antifungal activities. However, the precise mechanism for the biological activities of hamacanthins has not yet been elucidated. In the present study, the anti-angiogenic effects of 6"-debromohamacanthin A (DBHA), an active component of isolated hamacanthins, were evaluated in cultured human umbilical vascular endothelial cells (HUVEC) and endothelial-like cells differentiated from mouse embryonic stem (mES) cells. DBHA significantly inhibited vascular endothelial growth factor (VEGF)-induced cell proliferation, migration and tube formation in the HUVEC. DBHA also suppressed the capillary-like structure formation and the expression of platelet endothelial cell adhesion molecule (PECAM), an endothelial biomarker, in mES cell-derived endothelial-like cells. To further understand the precise molecular mechanism of action, VEGF-mediated signaling pathways were analyzed in HUVEC cells and mES cell-derived endothelial-like cells. DBHA suppressed the VEGF-induced expression of MAPKs (p38, ERK and SAPK/JNK) and the PI3K/AKT/mTOR signaling pathway. In addition, DBHA inhibited microvessel sprouting in mES/EB-derived embryoid bodies. In an ex vivo model, DBHA also suppressed the microvessel sprouting of mouse aortic rings. The findings suggest for the first time that DBHA inhibits angiogenesis by targeting the vascular endothelial growth factor receptor 2 (VEGFR2)-mediated PI3K/AKT/mTOR signaling pathway in endothelial cells.
Project description:Disorders of angiogenesis are related to microangiopathies during the development of diabetic vascular complications, but the effect of advanced glycation end products (AGEs) on angiogenesis and the mechanism has not been completely unveiled. We previous demonstrated that moesin belonging to the ezrin-radixin-moesin (ERM) protein family protein played a critical role in AGE-induced hyper-permeability in human umbilical vein endothelial cells (HUVECs). Here, we investigated the impact of moesin on AGE-induced HUVEC proliferation, migration, and tubulogenesis. Silencing of moesin decreased cell motility and tube formation but not cell proliferation. It also attenuated cellular F-actin reassembly. Further, phosphorylation of threonine at the 558 amino acid residue (Thr 558) in moesin suppressed AGE-induced HUVEC proliferation, migration, and tube formation, while the activating mutation of moesin at Thr 558 enhanced HUVEC angiogenesis. Further, the inhibition of either RhoA activity by adenovirus or ROCK activation with inhibitor Y27632 decreased AGE-induced moesin phosphorylation and subsequently suppressed HUVEC angiogenesis. These results indicate that the Thr 558 phosphorylation in moesin mediates endothelial angiogenesis. AGEs promoted HUVEC angiogenesis by inducing moesin phosphorylation via RhoA/ROCK pathway.