Targeting Vascular Endothelial Growth Factor Research Articles

Abstract PS13-12: Apatinib combined with taxanes and platinum neoadjuvant chemotherapy for patients with triple-negative and HER2-positive breast cancer: A multicenter, randomized, open-label, phase II trial

Abstract Background: Apatinib, a tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor 2 (VEGFR2), has demonstrated a promising efficacy in patients with metastatic breast cancer. For triple-negative and HER2-positive subtypes, increasing the pathological complete response (pCR) of neoadjuvant therapy may benefit their clinical outcomes. Here, we assessed whether the combination of Apatinib with neoadjuvant chemotherapy elevate the pCR rate in locally advanced breast cancer. Method: In this multicenter, open-label trial, we randomized 53 patients into TP neoadjuvant chemotherapy (docetaxel 75 mg/m2 or nab-paclitaxel 260 mg/m2 or paclitaxel liposome 175 mg/m2 day 1, and carboplatin AUC=6 or cisplatin 75 mg/m2 or lobaplatin 30 mg/m2 day 1), or combined with apatinib (500mg day 1-21) . Trastuzumab was added to neoadjuvant therapy in HER2-positive subtype. Six cycles were repeated every 3 weeks. Results: In total patients with stage IIb-IIIc triple-negative and HER2-positive breast cancer, the addition of apatinib to TP neoadjuvant chemotherapy (Apa+TP) significantly increased the pCR rate (70.8%, 17/24), compared with TP along (41.4%, 12/29), P=0.032. When separating patients into triple-negative (Apa+TP 66.7% (8/12) vs. TP 42.9% (3/7)) and HER2-positve (Apa+TP 75% (9/12) vs. TP 40.9% (9/22)) subtypes, the effect of apatinib on pCR was also improved though no significant differences were found (P=0.377; P=0.080 separately) compared with control group. The most common Grade 3-4 adverse events (AE) included hypertension (Apa+TP 12.5% vs. TP 0%, P=0.173), hand-foot syndrome (Apa+TP 8.3% vs. TP 0%, P=0.389) and erythra (Apa+TP 4.2% vs. TP 0%, P=0.924). No significant differences of toxic effects were found between Apa+TP and control group. Conclusion: Apatinib combined with TP neoadjuvant chemotherapy significantly increased the pCR rate in patients with locally advanced triple-negative and HER2-positive breast cancer, indicating an applicable strategy in the future. EfficacyTriple-negative breast cancer efficacyHer2-positive breast cancer efficacySafety Citation Format: Yunjiang Liu, Xiangmei Zhang, Li Wang, Miao Cao, Shuo Zhang, Hui Zhang, Yarong Zhou, Jintian Wang. Apatinib combined with taxanes and platinum neoadjuvant chemotherapy for patients with triple-negative and HER2-positive breast cancer: A multicenter, randomized, open-label, phase II trial [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS13-12.

CRISPR-dcas9 Optogenetic Nanosystem for the Blue Light-Mediated Treatment of Neovascular Lesions.

Vascular endothelial growth factor (VEGF) is the key regulator in neovascular lesions. The anti-VEGF injection is a major way to relieve retinal neovascularization and treat these diseases. However, current anti-VEGF therapeutics show significant drawbacks. The reason is the inability to effectively control its therapeutic effect. Therefore, how to controllably inhibit the VEGF target is a key point for preventing angiogenesis. Here, a CRISPR-dCas9 optogenetic nanosystem was designed for the precise regulation of pathologic neovascularization. This system is composed of a light-controlled regulatory component and transcription inhibition component. They work together to controllably and effectively inhibit the target gene's VEGF. The opto-CRISPR nanosystem achieved precise regulation according to individual differences, whereby the expression and interaction of gene was activated by light. The following representative model laser-induced choroid neovascularization and oxygen-induced retinopathy were taken as examples to verify the effect of this nanosystem. The results showed that the opto-CRISPR nanosystem was more efficacious in the light control group (NV area effectively reduced by 41.54%) than in the dark control group without light treatment. This strategy for the CRISPR-optogenetic gene nanosystem led to the development of approaches for treating severe eye diseases. Besides, any target gene of interest can be designed by merely replacing the guide RNA sequences in this system, which provided a method for light-controlled gene transcriptional repression.

Apatinib Plus Temozolomide: An Effective Salvage Treatment for Recurrent Glioblastoma.

BackgroundTreatment for recurrent glioblastoma is poor, and there is a need for better therapies. Here we retrospectively assessed the efficacy and toxicity of temozolomide plus apatinib, an oral small-molecule tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor 2 in recurrent glioblastoma.Materials and MethodsA retrospective analysis of patients with recurrent glioblastoma who underwent apatinib plus temozolomide treatment was performed. Apatinib was given at 500 mg once daily. Temozolomide was administered at 200 mg/m2/d on days 1–5 or 50 mg/m2/d continuous daily according to whether they had experienced temozolomide maintenance treatment before. The main clinical data collected included tumor characteristics, status of MGMT promoter, and IDH mutation, number of relapse, response, survival, adverse reactions, and salvage therapies.ResultsFrom April 2016 to August 2019, thirty-one patients were identified. The objective response rate was 26.3%, and the disease control rate was 84.2%. The progression-free survival (PFS) at 6 months and overall survival (OS) at 12 months were 44.6 and 30.2%. The median PFS and OS were 4.9 and 8.2 months, respectively. Two patients achieved long PFS of 30.9 and 38.7+ months. The median survival time after progression of the patients with or without salvage bevacizumab was 5.1 versus 1.2 months. The most common grade 3 or 4 toxicities were hypertension (5.8%), decreased appetite (5.8%), and thrombocytopenia (4.3%), most of which were resolved after symptomatic treatment or dose reduction.ConclusionApatinib plus temozolomide is an effective salvage regimen with manageable toxicities for recurrent glioblastoma and could not reduce the sensitivity to bevacizumab.

IMbrave 151: a randomized phase II trial of atezolizumab combined with bevacizumab and chemotherapy in patients with advanced biliary tract cancer.

Background:Biliary tract cancers (BTCs) are heterogenous, highly aggressive tumors that harbor a dismal prognosis for which more effective treatments are needed. The role of cancer immunotherapy in BTC remains to be characterized. The tumor microenvironment (TME) of BTC is highly immunosuppressed and combination treatments are needed to promote effective anticancer immunity. Vascular endothelial growth factor (VEGF) drives immunosuppression in the TME by disrupting antigen presentation, limiting T-cell infiltration, or potentiating immune-suppressive cells. Many VEGF-regulated mechanisms are thought to be relevant to repressed antitumor immunity in BTC, making dual targeting of VEGF and programmed cell death protein 1 (PD-1)/PD-L1 pathways a rational approach. Gemcitabine and Cisplatin (Gem/Cis) can also modulate anticancer immunity through overlapping and complementary mechanisms to those regulated by VEGF. Anti-PD-L1/VEGF inhibition, coupled with chemotherapy, may potentiate antitumor immunity leading to enhanced clinical benefit.Methods:IMbrave 151 is a randomized, double-blind, placebo-controlled, multicenter, international phase II study to evaluate atezolizumab (a PD-L1 inhibitor) in combination with chemotherapy (gemcitabine and cisplatin) and bevacizumab (an anti-VEGF monoclonal antibody) as a first-line treatment for advanced BTC. Approximately 150 patients with previously untreated, advanced BTC will be randomized to either Arm A (atezolizumab + bevacizumab + Gem/Cis) or Arm B (atezolizumab + placebo + Gem/Cis). Randomization is stratified by the presence of metastatic disease, primary tumor location, and geographic region. The primary efficacy endpoint is investigator-assessed progression-free survival (PFS) per RECIST 1.1. Secondary endpoints include objective response rate (ORR), duration of response (DoR), disease control rate (DCR), overall survival (OS), and safety and patient reported outcomes (PROs). Tissue, blood, and stool samples will be collected at baseline and on-treatment in order to perform correlative biomarker analyses.Discussion:IMbrave 151 represents the first randomized study to evaluate combined PD-L1/VEGF blockade on a chemotherapy backbone in BTC.Trial registration:NCT identifier: NCT04677504; EUDRACT number: 2020-003759-14

Molecular Targeting of VEGF with a Suramin Fragment-DOCA Conjugate by Mimicking the Action of Low Molecular Weight Heparins.

Molecular targeting of growth factors has shown great therapeutic potential in pharmaceutical research due to their roles in pathological conditions. In the present study, we developed a novel suramin fragment and deoxycholic acid conjugate (SFD) that exhibited the potential to bind to the heparin-binding site (HBD) of vascular endothelial growth factor (VEGF) and to inhibit its pathogenic action for the first time. Notably, SFD was optimally designed for binding to the HBD of VEGF using the naphthalenetrisulfonate group, allowing to observe its excellent binding efficacy in a surface plasmon resonance (SPR) study, showing remarkable binding affinity (KD = 3.8 nM) as a small molecule inhibitor. In the tubular formation assay, it was observed that SFD could bind to HBD and exhibit antiangiogenic efficacy by inhibiting VEGF, such as heparins. The cellular treatment of SFD resulted in VEGF-inhibitory effects in human umbilical vein endothelial cells (HUVECs). Therefore, we propose that SFD can be employed as a novel drug candidate to inhibit the pathophysiological action of VEGF in diseases. Consequently, SFD, which has a molecular structure optimized for binding to HBD, is put forward as a new chemical VEGF inhibitor.

Acute and chronic effects of intravitreal bevacizumab on lung biomarkers of angiogenesis in the rat exposed to neonatal intermittent hypoxia

Purpose/Aim Intravitreal bevacizumab (Avastin) is an irreversible vascular endothelial growth factor (VEGF) inhibitor used to treat severe retinopathy of prematurity (ROP) in extremely low gestational age neonates (ELGANs). ELGANs who are at the highest risk for developing severe ROP often experience brief intermittent hypoxia (IH) episodes which may cause oxidative damage. We tested the hypothesis that intravitreal Avastin leaks into the systemic circulation during exposure to IH and has adverse effects on biomarkers of pulmonary microvascular maturation, thus leading to pulmonary hemorrhage and long-term pulmonary sequelae. Methods Neonatal rats at postnatal day (PN) 0 (birth) were exposed to either: 1) hyperoxia (50% O2) or 2) neonatal IH (50% O2 with brief episodes of 12% O2) from PN0 to PN14. Room air (RA) littermates served as controls. At PN14, the time of eye opening in rats, a single dose of Avastin (0.125 mg in 5 µL) was injected into the vitreous cavity of the left eyes. A control group received equivalent volume saline. At PN23 and PN45, blood gases, lung-to-body weight ratios, histology, immunofluorescence, and lung biomarkers of angiogenesis were examined. Results At PN23, Avastin increased lung VEGF, nitric oxide derivatives (NOx), and hypoxia-inducible factor (HIF)1a in the hyperoxia-exposed groups, but decreased soluble VEGFR-1 (sVEGFR-1). At PN45, lungs from animals exposed to neonatal IH and treated with Avastin were severely hemorrhagic with morphologic changes in lung architecture consistent with chronic lung disease. This was associated with higher VEGF and NOx levels, and lower insulin-like growth factor (IGF)-I and sVEGFR-1. Conclusions These findings prove our hypothesis that intravitreal Avastin penetrates the blood–ocular barrier in IH and alters lung biomarkers of angiogenesis. Avastin targeting of VEGF could affect normal lung development which may be exaggerated under pathologic conditions such as IH, ultimately leading to vascular permeability, vessel rupture, and pulmonary hemorrhage.

MiR-628–5p Inhibits Cervical Carcinoma Proliferation and Promotes Apoptosis by Targeting VEGF

BackgroundIt has been reported that the dysregulation of microRNAs (miRNAs) is implicated in the biological processes of diverse diseases, including the tumorigenesis of human cancers. MicroRNA-628–5p (miR-628–5p) is differentially expressed and plays a critical role in several cancers, but the role of miR-628–5p in cervical cancer has not been well studied. MethodsThe TCGA database and RT-qPCR were used to evaluate the expression profile of miR-628–5p in cervical cancer tissues. Transfection efficiency of synthetic miRNAs was detected using RT-qPCR. The biological effects of miR-628–5p on cervical cancer cells were assessed by the CCK-8 assay, flow cytometry, western blot analysis, and the tube formation assay. The expression levels of key proteins involved in cell apoptosis, the cell cycle and the PI3K pathway were analyzed by western blot analysis. Bioinformatic analysis and the luciferase reporter assay were performed to investigate the targeted relationship between miR-628–5p and vascular endothelial growth factor (VEGF). ResultsMiR-628–5p was downregulated and negatively correlated with Ki-67 expression in cervical cancer tissues, and its low level predicted poor survival of patients. Functional assays indicated that miR-628–5p inhibited cell proliferation and promoted cell apoptosis. Mechanically, VEGF was verified to be a downstream target of miR-628–5p. Moreover, overexpression of VEGF could reverse the effects of miR-628–5p on VEGF/PI3K/AKT signaling, cell proliferation, apoptosis, the cell cycle and angiogenesis in cervical cancer. ConclusionsMiR-628–5p inhibited cervical cancer cell proliferation and promoted apoptosis by targeting VEGF.

Altered Regulation of HIF-1α in Naive- and Drug-Resistant EGFR-Mutant NSCLC: Implications for a Vascular Endothelial Growth Factor-Dependent Phenotype.

The treatment of patients with EGFR-mutant NSCLC with vascular endothelial growth factor (VEGF) inhibitors in combination with EGFR inhibitors provides a greater benefit than EGFR inhibition alone, suggesting that EGFR mutation status may define a patient subgroup with greater benefit from VEGF blockade. The mechanisms driving this potentially enhanced VEGF dependence are unknown. We analyzed the effect of EGFR inhibition on VEGF and HIF-1α in NSCLC models invitro and invivo. We determined the efficacy of VEGF inhibition in xenografts and analyzed the impact of acquired EGFR inhibitor resistance on VEGF and HIF-1α. NSCLC cells with EGFR-activating mutations exhibited altered regulation of VEGF compared with EGFR wild-type cells. In EGFR-mutant cells, EGFR, not hypoxia, was the dominant regulator of HIF-1α and VEGF. NSCLC tumor models bearing classical or exon 20 EGFR mutations were more sensitive to VEGF inhibition than EGFR wild-type tumors, and a combination of VEGF and EGFR inhibition delayed tumor progression. In models of acquired EGFR inhibitor resistance, whereas VEGF remained overexpressed, the hypoxia-independent expression of HIF-1α was delinked from EGFR signaling, and EGFR inhibition no longer diminished HIF-1α or VEGF expression. In EGFR-mutant NSCLC, EGFR signaling is the dominant regulator of HIF-1α and VEGF in a hypoxia-independent manner, hijacking an important cellular response regulating tumor aggressiveness. Cells with acquired EGFR inhibitor resistance retained elevated expression of HIF-1α and VEGF, and the pathways were no longer EGFR-regulated. This supports VEGF targeting in EGFR-mutant tumors in the EGFR inhibitor-naive and refractory settings.

Virus Mimetic Shell-Sheddable Chitosan Micelles for siVEGF Delivery and FRET-Traceable Acid-Triggered Release.

Targeting vascular endothelial growth factor (VEGF) using small interfering RNA (siVEGF) has shown great potential in inhibiting the growth, proliferation, and migration of tumors by reducing the proliferation of blood vessels. On the basis of bionic principles, a novel pH-responsive and virus mimetic shell-sheddable chitosan (CS) micelles (CMs) as siRNA delivery system was introduced in this study. The cyclo(Arg-Gly-Asp-d-Phe-Lys) (cRGD) modified poly(enthylene glycol) (PEG) was conjugated to the HA2 modified chitosan via a hydrazone linkage (cRGD-PEG-Hz-CS-HA2). The cRGD-PEG-Hz-CS-HA2 conjugate could form micelles by interacting with the complex of octanal, Boc-l-lysine, and 9-d-arginine (9R) (octyl-Lys-9R) as a hydrophodic core forming agent, termed as cRGD-PEG-Hz-CS-HA2/octyl-Lys-9R (abbreviated as cRGD/HA2/Hz-CMs).The CMs modified with cRGD can accurately target glioma cells (U87MG cells) with high expression of αvβ3. The payloads of siVEGF were packed into the core of cRGD/HA2/Hz-CMs via electrostatic interaction and hydrophobic interaction. The intracellular cargo release was achieved by the pH-responsive lysis of the hydrazone bond in acidic environment of endosome. Moreover, the exposed HA2, as a pH-sensitive membrane-disruptive peptide, assists the escape of the carriers from endosome into cytosol. In addition, cRGD/HA2/Hz-CMs can effectively deliver siVEGF and silence VEGF gene expression in U87MG cells, leading to the significant tumor growth inhibition. This study demonstrates that cRGD/HA2/Hz-CMs can deliver and release siVEGF in a controlled manner, which was traced by the fluorescence resonance energy transfer (FRET) system in order to achieve RNAi-based anti-angiogenic treatment of cancer in vivo.

Value of ultrasound-targeted vascular endothelial growth factor receptor-2 in non-invasive monitoring of anti-angiogenic response in nude mice with subcutaneous xenograft model

Objective: To investigate the value of contrast-enhanced ultrasound targeting vascular endothelial growth factor receptor-2 (VEGFR-2) in non-invasive monitoring of anti-angiogenesis response in subcutaneous transplantation tumor model of hepatocellular carcinoma in nude mice. Methods: Sixteen nude mice were randomly divided into control group and bevacizumab treatment group (treatment group). Two weeks later, the model of subcutaneous transplanted tumor was established. The mice in the treatment group were intratumorally injected with 0.2 mg bevacizumab, while the control group was given the same amount of saline, three times a week for 2 weeks. Ultrasound microbubbles targeting VEGFR-2 were prepared by biotin avidin method. Ultrasound examinations were performed before treatment, 7 days and 14 days after treatment, and the time intensity curve (TIC) was drawn to quantitatively analyze the differences of parameters with treatment time. The expression of CD31 in tumor tissues was detected by immunohistochemistry. Results: After 14 days of treatment, the volume of tumor tissue in the treatment group and the control group were (0.247±0.019) mm(3) and (0.307±0.031) mm(3,) respectively, the difference was statistically significant (P<0.01). After 7 days of treatment, the rise slope (K(1)), time to peak (TTP) and peak intensity (PI) of TIC curve in the treatment group were 3.77±0.62, (3.82±0.21) s and (24.35±3.34) dB, respectively, which were significantly different from 2.93±0.31, (4.47±0.50) s and (30.10±2.35) dB in the control group, respectively (P<0.05). Immunohistochemistry showed that the PI of contrast enhanced ultrasound was positively correlated with microvessel density (r(2)=0.898, P=0.017). Conclusions: The therapeutic effect of bevacizumab on tumor angiogenesis evaluated by contrast-enhanced ultrasound targeting VEGFR-2 is related to the differences of parameters such as K(1), TTP and PI of TIC index. Contrast enhanced ultrasound targeting VEGFR-2 is of great value in non-invasive monitoring of subcutaneous transplanted tumor model of hepatocellular carcinoma in nude mice.

Concurrent Apatinib and Brain Radiotherapy in Patients With Brain Metastases From Driver Mutation-negative Non–small-cell Lung Cancer: Study Protocol for an Open-label Randomized Controlled Trial

Brain radiotherapy (BR) is a well-recognized approach for multiple brain metastases (BMs) from non–small-cell lung cancer (NSCLC). However, the prognosis for these patients remains poor. Apatinib, an antiangiogenic agent targeting vascular endothelial growth factor receptor-2, has shown excellent efficacy in multiple solid tumors. This phase II (WWW. ClinicalTrials.gov Identifier: VEGFR-2 NCT03801200) randomized trial aims to evaluate the efficacy and safety of this combined modality paradigm in patients with BMs from driver mutation-negative NSCLC. This is a multicenter, open-label, randomized controlled clinical trial. A total of 90 eligible patients will be allocated in a 1:1 ratio, to either the experimental group (concurrent apatinib and BR) or the control group (BR alone). The primary endpoint is intracranial progression-free survival. The secondary endpoints include intracranial objective response rate, intracranial disease control rate, intracranial time to progression, overall survival, and occurrence of peritumoral brain edema using standardized measurement. Quality of life and adverse events will also be evaluated. Assessments will be carried out before enrollment (baseline) along with 4 and 12 weeks after radiotherapy, followed by every 12 weeks thereafter and up to 24 months. In summary, the aim of this trial is to demonstrate the clinical efficacy and safety of concurrent BR and apatinib in patients with driver mutation-negative NSCLC with multiple BMs, in efforts to expand management options for this population with poor prognosis.

Development of Human CBF1-Targeting Single-Stranded DNA Aptamers with Antiangiogenic Activity In Vitro.

C promoter binding factor 1 (CBF1) (alias RBPJ) is a critical transcription factor involved in Notch signaling. The activation of Notch signaling through CBF1 maintains the angiostatic state of endothelial cells suppressing angiogenesis, that is, the formation of new blood vessels. Vascular endothelial growth factor (VEGF) induces angiogenesis by promoting the proteasomal degradation of CBF1, in addition to endothelial cell proliferation. To date, angiogenic inhibitors targeting VEGF have been successfully used in clinics for cancer and age-related macular degeneration. Most antiangiogenic drugs, however, only target VEGF or VEGF receptors. In this study, to expand the repertoire of antiangiogenic therapeutics, we developed 15 single-stranded deoxyribonucleic acid (ssDNA) aptamers capable of binding to CBF1 with high affinity (Kd; 10-300 nM). To this end, systematic evolution of ligands by the exponential enrichment (SELEX) method was applied. One of the CBF1-binding ssDNA aptamers, Apt-3, inhibited angiogenesis through the activation of Notch signaling in vitro. We found that Apt-3 directly interacted with the LAG1 domain of CBF1. We suggest that the Apt-3 ssDNA aptamer may contribute to the development of a novel angiogenic inhibitor, which does not target VEGF.

Inactivation of endothelial cell phosphoinositide 3-kinase β inhibits tumor angiogenesis and tumor growth.

Angiogenesis inhibitors, such as the receptor tyrosine kinase (RTK) inhibitor sunitinib, target vascular endothelial growth factor (VEGF) signaling in cancers. However, only a fraction of patients respond, and most ultimately develop resistance to current angiogenesis inhibitor therapies. Activity of alternative pro-angiogenic growth factors, acting via RTK or G-protein coupled receptors (GPCR), may mediate VEGF inhibitor resistance. The phosphoinositide 3-kinase (PI3K)β isoform is uniquely coupled to both RTK and GPCRs. We investigated the role of endothelial cell (EC) PI3Kβ in tumor angiogenesis. Pro-angiogenic GPCR ligands were expressed by patient-derived renal cell carcinomas (PD-RCC), and selective inactivation of PI3Kβ reduced PD-RCC-stimulated EC spheroid sprouting. EC-specific PI3Kβ knockout (ΕC-βKO) in mice potentiated the sunitinib-induced reduction in subcutaneous growth of LLC1 and B16F10, and lung metastasis of B16F10 tumors. Compared to single-agent sunitinib treatment, tumors in sunitinib-treated ΕC-βKO mice showed a marked decrease in microvessel density, and reduced new vessel formation. The fraction of perfused mature tumor microvessels was increased in ΕC-βKO mice suggesting immature microvessels were most sensitive to combined sunitinib and PI3Kβ inactivation. Taken together, EC PI3Kβ inactivation with sunitinib inhibition reduces microvessel turnover and decreases heterogeneity of the tumor microenvironment, hence PI3Kβ inhibition may be a useful adjuvant antiangiogenesis therapy with sunitinib.

270P Apatinib added to taxanes and platinum neoadjuvant chemotherapy for patients with triple-negative and HER2-positive breast cancer: A multicenter, randomized, phase II, open-label trial

Triple-negative and epidermal growth factor receptor 2 (HER2)-positive breast cancer represent the aggressive molecular subtypes. Neoadjuvant therapy plays an important role in improving the disease prognosis. Apatinib, a tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor 2 (VEGFR2), combined with taxanes have demonstrated a promising anti-tumour activity in patients with metastatic breast cancer. Here, we performed a multicenter, randomized, phase II, open-label trial for patients with stage IIb-IIIc breast cancer, aiming determining whether the addition of apatinib to neoadjuvant chemotherapy increase the rate of pathological complete response (pCR).

Small extracellular vesicle-bound vascular endothelial growth factor secreted by carcinoma-associated fibroblasts promotes angiogenesis in a bevacizumab-resistant manner.

The blood vessel growth inhibitor bevacizumab targets vascular endothelial growth factor (VEGF), a crucial regulator of angiogenesis. Recently, small extracellular vesicles (sEVs) have been demonstrated to be important vehicles in the transport of growth factors to target cells. In this study, we isolated primary carcinoma-associated fibroblasts (CAFs) from four human oral squamous cell carcinoma (OSCC) specimens. Compared with other non-extracellular vesicle components, CAF-derived sEVs were found to be the main regulators of angiogenesis. The ability of CAF sEVs to activate VEGF receptor 2 (VEGFR2) signaling in human umbilical vein endothelial cells (HUVEC) was dependent on the association between sEVs and VEGF. In addition, sEV-bound VEGF secreted by CAFs further activated VEGFR2 signaling in HUVEC in a bevacizumab-resistant manner. VEGF was found to interact with heparan sulfate proteoglycans on the CAF sEV surface and could be released by heparinase I/III. The bioactivity of the dissociated VEGF was retained in vitro and in vivo and could be neutralized by bevacizumab. These findings suggest that the combined use of heparinase and bevacizumab might inhibit angiogenesis in patients with high levels of sEV-bound VEGF.

Vandetanib inhibits cell growth in EGFR-expressing cutaneous squamous cell carcinoma

Advanced cutaneous squamous cell carcinoma (SCC) responds poorly to chemotherapy, leading to significant morbidity or death. Overexpression of epidermal growth factor receptor (EGFR) is frequently observed in advanced cutaneous SCC. Vandetanib is a multiple tyrosine kinase targeting vascular endothelial growth factor receptor-2 (VEGFR2), EGFR, and the rearranged during transfection (RET) proto-oncogene. Vandetanib has been reported to inhibit tumor growth in head and neck SCC. However, the efficacy of vandetanib against cutaneous SCC has not been thoroughly investigated. The aim of this study is to evaluate the efficacy of vandetanib against cutaneous SCC in vitro and in vivo. Vandetanib is found to inhibit the proliferation of cutaneous SCC cells as assessed by cell viability and clonogenic assay. Cell death analysis indicates that vandetanib induces cell death in SCC cells but not in normal human keratinocytes or fibroblasts. The in vivo anti-tumor effect of vandetanib is shown in xenograft tumor models using A431 SCC cells. Mechanistically, vandetanib suppresses the phosphorylation of EGFR in SCC cells. Clinically, EGFR expression levels are elevated in cutaneous SCC specimens, relative to normal epidermis. In conclusion, we identified vandetanib as a novel therapeutic option for cutaneous SCC, especially in tumors with high EGFR expression.

Abstract CT142: A phase I trial of surufatinib plus toripalimab in patients with advanced solid tumor

Abstract Background: Surufatinib is a novel small-molecule inhibitor targeting vascular endothelial growth factor receptors 1, 2 and 3, fibroblast growth factor receptor 1 and colony stimulating factor 1 receptor. Toripalimab (JS001) is a monoclonal humanized IgG4 PD-1 antibody. The potential synergistic antitumor activity of surufatinib and anti-PD-L1 combination regimen had been demonstrated in preclinical study (presented at 2017 AACR). Here, we report the safety and preliminary efficacy results from a phase I trial of surufatinib plus toripalimab in patients with advanced solid tumor (NCT03879057). Methods: This study is an open-label, dose escalation and expansion study in solid tumor patients who had failed standard therapies or had no effective treatment. In dose escalation stage, 3 dose levels of surufatinib (200, 300 and 250 mg once daily) were evaluated in combination with a fixed dose of toripalimab 240 mg every 3 weeks until the maximum tolerated dose (MTD) or recommended phase II dose (RP2D) was reached, which ever occurred first. Additional patients were enrolled at dose expansion phase to further assess the efficacy, safety and pharmacokinetic (PK) profile. Results: As of 2020-1-20, a total of 30 patients were enrolled. Tumor types include neuroendocrine tumor (NET) Grade (G) 1/2 (4), NET G3 (4), neuroendocrine carcinoma (NEC) (13), colorectal carcinoma (CRC) (4), gastric adenocarcinoma (GC) (2), esophageal squamous cell carcinoma (ESCC) (2) and metastatic squamous cell carcinoma with unknown primary (1). The RP2D was determined at surufatinib 250 mg daily plus toripalimab. One patient at 300 mg experienced dose-limiting toxicity, grade 3 hyperthyroidism. The most common grade 3/4 treatment emergent adverse events (TEAE, ≥5%) were transaminase elevation, bilirubin elevation, fatigue, hyponatremia, and vomit, with higher frequencies in the 300 mg cohort compared with lower dose cohorts. There was no treatment-related fatal serious adverse event. Preliminary PK analysis showed surufatinib exposure at steady state increased dose-proportionally. Individual PK profiles was comparable to those of surufatinib or toripalimab from previous monotherapy trials. By 2020-1-10, 25/30 patients across 3 cohorts were evaluable for tumor response: 1 complete response, 6 partial response (ORR=28%); in NET G1/2 (3), NEC (2), ESCC (1), and CRC (1). Twelve patients experienced stable disease for at least 6 weeks (DCR=76%). Most patients with negative or low PD-L1 expression achieved PR or CR. Of 21 evaluable neuroendocrine neoplasms (NENs) patients, the ORR and DCR were 23.8% and 81.0%, respectively. Four of 8 evaluable patients at RP2D achieved PR, and the ORR and DCR were 50% and 100%, respectively. Conclusions: Surufatinib plus toripalimab were well tolerated with no unexpected safety signals observed, and showed encouraging antitumor activity in patients with advanced solid tumor, especially in NENs patients. The phase II trial (NCT04169672) has been initiated. Citation Format: Ming Lu, Yanshuo Cao, Jifang Gong, Yu Sun, Jie Li, Lin Shen. A phase I trial of surufatinib plus toripalimab in patients with advanced solid tumor [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT142.

Epitope Mapping for a Preclinical Bevacizumab (Avastin) Biosimilar on an Extended Construct of Vascular Endothelial Growth Factor A Using Millisecond Hydrogen-Deuterium Exchange Mass Spectrometry.

The success of bevacizumab (Avastin), a monoclonal antibody (mAb) anticancer drug targeting vascular endothelial growth factor A (VEGF-A), has motivated the development of biosimilars. Establishing target epitope similarity using epitope mapping is a critical step in preclinical mAb biosimilar development. Here we use time-resolved electrospray ionization hydrogen-deuterium exchange (HDX) mass spectrometry to rapidly compare the epitopes of commercial Avastin and a biosimilar in preclinical development (ApoBev) on an extended construct of VEGF-A. The Avastin and ApoBev epitopes determined in our experiments agree with each other and with the known epitope derived from the Avastin Fab domain/truncated VEGF co-crystal structure. However, subtly different allosteric effects observed exclusively at short (millisecond) HDX labeling times may reflect a slightly different binding mode for ApoBev.

P-128 A novel combination of GEMOX and apatinib in treatment of unresectable or metastatic cholangiocellular carcinoma

The treatment of unresectable/metastatic cholangiocellular carcinoma (CCC) is limited and the response rate of chemotherapy is unsatisfactory. Apatinib, a novel antiangiogenic agent targeting vascular endothelial growth factor receptor (VEGFR2), is currently being studied in different tumors. This study was performed to assess the response rate and safety of apatinib in patients with unresectable/metastatic CCC.

Nanoparticle Delivery of Proangiogenic Transcription Factors into the Neonatal Circulation Inhibits Alveolar Simplification Caused by Hyperoxia.

Rationale: Advances in neonatal critical care have greatly improved the survival of preterm infants, but the long-term complications of prematurity, including bronchopulmonary dysplasia (BPD), cause mortality and morbidity later in life. Although VEGF (vascular endothelial growth factor) improves lung structure and function in rodent BPD models, severe side effects of VEGF therapy prevent its use in patients with BPD.Objectives: To test whether nanoparticle delivery of proangiogenic transcription factor FOXM1 (forkhead box M1) or FOXF1 (forkhead box F1), both downstream targets of VEGF, can improve lung structure and function after neonatal hyperoxic injury.Methods: Newborn mice were exposed to 75% O2 for the first 7 days of life before being returned to a room air environment. On Postnatal Day 2, polyethylenimine-(5) myristic acid/polyethylene glycol-oleic acid/cholesterol nanoparticles containing nonintegrating expression plasmids with Foxm1 or Foxf1 cDNAs were injected intravenously. The effects of the nanoparticles on lung structure and function were evaluated using confocal microscopy, flow cytometry, and the flexiVent small-animal ventilator.Measurements and Main Results: The nanoparticles efficiently targeted endothelial cells and myofibroblasts in the alveolar region. Nanoparticle delivery of either FOXM1 or FOXF1 did not protect endothelial cells from apoptosis caused by hyperoxia but increased endothelial proliferation and lung angiogenesis after the injury. FOXM1 and FOXF1 improved elastin fiber organization, decreased alveolar simplification, and preserved lung function in mice reaching adulthood.Conclusions: Nanoparticle delivery of FOXM1 or FOXF1 stimulates lung angiogenesis and alveolarization during recovery from neonatal hyperoxic injury. Delivery of proangiogenic transcription factors has promise as a therapy for BPD in preterm infants.