Inhibition of VEGF-dependent angiogenesis and tumor angiogenesis by an optimized antibody targeting CLEC14a

Group XIV C-type lectins: emerging targets in tumor angiogenesis

C-type lectins, distinguished by a C-type lectin binding domain (CTLD), are an evolutionarily conserved superfamily of glycoproteins that are implicated in a broad range of physiologic processes. The group XIV subfamily of CTLDs are comprised of CD93, CD248/endosialin, CLEC14a, and thrombomodulin/CD141, and have important roles in creating and maintaining blood vessels, organizing extracellular matrix, and balancing pro- and anti-coagulative processes. As such, dysregulation in the expression and downstream signaling pathways of these proteins often lead to clinically relevant pathology. Recently, group XIV CTLDs have been shown to play significant roles in cancer progression, namely tumor angiogenesis and metastatic dissemination. Interest in therapeutically targeting tumor vasculature is increasing and the search for novel angiogenic targets is ongoing. Group XIV CTLDs have emerged as key moderators of tumor angiogenesis and metastasis, thus offering substantial therapeutic promise for the clinic. Herein, we review our current knowledge of group XIV CTLDs, discuss each's role in malignancy and associated potential therapeutic avenues, briefly discuss group XIV CTLDs in the context of two other relevant lectin families, and offer future direction in further elucidating mechanisms by which these proteins function and facilitate tumor growth.

Pharmacokinetic evaluation of radiolabeled intraocular anti-CLEC14a antibody in preclinical animal species and application in humans

Anti-angiogenic antibodies are widely used in the treatment of neovascular macular degeneration. Human antibody targeting C-type lectin domain family 14 member A (CLEC14a) is potential therapeutic agents owing to its antiangiogenic activity. In the present study, we aimed to predict the human intraocular pharmacokinetic (PK) properties of an anti-CLEC14a antibody. I-125 labeled aflibercept and anti-CLEC14a antibody were intravitreally injected into mice, rats, and rabbits. Single photon emission computed tomography/computed tomography imaging was performed, and the intraocular radioactivity concentration (%ID/ml) was obtained. The PK parameters in those three animal species were obtained by compartmental analysis. The PK parameters in humans were estimated by allometric scaling of the animal PK parameters with consideration of the hydrodynamic radius of the antibody. The mean half-life values of intraocular I-125-labeled aflibercept in mice, rats, and rabbits were 1.13 days, 1.25 days, and 4.91 days, respectively, by analysis with a one-compartment model. The predicted human half-life of intraocular aflibercept was 5.75 days based on vitreal volume by allometric scaling. The half-life values of intraocular I-125-labeled anti-CLEC14a in mice, rats and rabbits were 1.05 days, 1.84 days, and 6.37 days, respectively, by analysis with a one-compartment model. The predicted human half-life of intraocular anti-CLEC14a was 10.29 days based on vitreal volume. According to the hydrodynamic volume of the anti-CLEC14a, the predicted human half-life of intraocular anti-CLEC14a was 9.81 days. The PK characteristics of the intraocular anti-CLEC14a antibody were evaluated noninvasively in animals using I-125 labeling, and the intraocular PK characteristics in humans were predicted using these animal data. This methodology can be applied for the development of new antiangiogenic antibodies to treat macular degeneration.

Effect of chemokine CXCL14 on in vitro angiogenesis of human hepatocellular carcinoma cells

The study was designed to investigate the effect of chemokine CXCL14 on in vitro angiogenesis of human hepatocellular carcinoma (HCC) cells. CXCL14 mRNA expression in HCC tissue samples and adjacent tissue samples was detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR). CXCL14 mRNA and protein expression in human normal hepatocyte HL-7702 and HCC cell line HepG2 were detected by qRT-PCR and western blot. In HepG2 cell line, the expression of vascular endothelial growth factor (VEGF) was detected by enzyme-linked immunosorbent assay method, cell viability was detected by CCK-8, cell proliferation was detected by colony formation assay, and cell migration as well as invasion ability was detected by Transwell assay. Moreover, human umbilical vein endothelial cell (HUVEC) tube formation assay was carried out to determine the cell ability of angiogenesis. Results showed that the overexpression of CXCL14 could inhibit angiogenesis, proliferation, migration, and invasion abilities of HCC cells.Highlights CXCL14 is lowly expressed in hepatocellular carcinoma tissues and cells. CXCL14 overexpression inhibits the angiogenesis of hepatocellular carcinoma cells. CXCL14 overexpression inhibits proliferation, invasion, and migration of hepatocellular carcinoma cells.

Structural and Functional Analysis of CEX Fractions Collected from a Novel Avastin® Biosimilar Candidate and Its Innovator: A Comparative Study

Avastin^® is a humanized recombinant monoclonal antibody used to treat cancer by targeting VEGF-A to inhibit angiogenesis. SIMAB054, an Avastin^® biosimilar candidate developed in this study, showed a different charge variant profile than its innovator. Thus, it is fractionated into acidic, main, and basic isoforms and collected physically by Cation Exchange Chromatography (CEX) for a comprehensive structural and functional analysis. The innovator product, fractionated into the same species and collected by the same method, is used as a reference for comparative analysis. Ultra-Performance Liquid Chromatography (UPLC) ESI-QToF was used to analyze the modifications leading to charge heterogeneities at intact protein and peptide levels. The C-terminal lysine clipping and glycosylation profiles of the samples were monitored by intact mAb analysis. The post-translational modifications, including oxidation, deamidation, and N-terminal pyroglutamic acid formation, were determined by peptide mapping analysis in the selected signal peptides. The relative binding affinities of the fractionated charge isoforms against the antigen, VEGF-A, and the neonatal receptor, FcRn, were revealed by Surface Plasmon Resonance (SPR) studies. The results show that all CEX fractions from the innovator product and the SIMAB054 shared the same structural variants, albeit in different ratios. Common glycoforms and post-translational modifications were the same, but at different percentages for some samples. The dissimilarities were mostly originating from the presence of extra C-term Lysin residues, which are prone to enzymatic degradation in the body, and thus they were previously assessed as clinically irrelevant. Another critical finding was the presence of different glyco proteoforms in different charge species, such as increased galactosylation in the acidic and afucosylation in the basic species. SPR characterization of the isolated charge variants further confirmed that basic species found in the CEX analyses of the biosimilar candidate were also present in the innovator product, although at lower amounts. The charge variants’ in vitro antigen- and neonatal receptor-binding activities varied amongst the samples, which could be further investigated in vivo with a larger sample set to reveal the impact on the pharmacokinetics of drug candidates. Minor structural differences may explain antigen-binding differences in the isolated charge variants, which is a key parameter in a comparability exercise. Consequently, such a biosimilar candidate may not comply with high regulatory standards unless the binding differences observed are justified and demonstrated not to have any clinical impact.

Classification of colon adenocarcinoma based on immunological characterizations: Implications for prognosis and immunotherapy

Accurate immune molecular typing is pivotal for screening out patients with colon adenocarcinoma (COAD) who may benefit from immunotherapy and whose tumor microenvironment (TME) was needed for reprogramming to beneficial immune-mediated responses. However, little is known about the immune characteristic of COAD. Here, by calculating the enrichment score of immune characteristics in three online COAD datasets (TCGA-COAD, GSE39582, and GSE17538), we identified 17 prognostic-related immune characteristics that overlapped in at least two datasets. We determined that COADs could be stratified into three immune subtypes (IS1–IS3), based on consensus clustering of these 17 immune characteristics. Each of the three ISs was associated with distinct clinicopathological characteristics, genetic aberrations, tumor-infiltrating immune cell composition, immunophenotyping (immune “hot” and immune “cold”), and cytokine profiles, as well as different clinical outcomes and immunotherapy/therapeutic response. Patients with the IS1 tumor had high immune infiltration but immunosuppressive phenotype, IS3 tumor is an immune “hot” phenotype, whereas those with the IS2 tumor had an immune “cold” phenotype. We further verified the distinct immune phenotype of IS1 and IS3 by an in-house COAD cohort. We propose that the immune subtyping can be utilized to identify COAD patients who will be affected by the tumor immune microenvironment. Furthermore, the ISs may provide a guide for personalized cancer immunotherapy and for tumor prognosis.

Interleukin-19 Promotes Retinal Neovascularization in a Mouse Model of Oxygen-Induced Retinopathy

Purpose

Retinal neovascularization is a major cause of blindness. This study aimed to investigate the effects of IL-19 and the underlying mechanisms in a mouse model of oxygen-induced retinopathy (OIR).

Methods

C57BL/6J wild-type mice and IL-19 knockout (KO) mice were used to establish an OIR mouse model. Bone marrow–derived macrophages (BMDMs) with or without recombinant IL-19 (rIL-19) stimulation were injected intravitreally. Reverse transcription-quantitative polymerase chain reaction was used to determine the mRNA expressions. ELISA and western blotting were performed to assess the protein levels. Immunofluorescence staining was applied to assess retinal neovascularization. Human retinal endothelial cells (HRECs) stimulated with rIL-19 were cultured to evaluate the effects on cell proliferation and migration.

Results

The level of IL-19 was significantly elevated at postnatal day 17 in OIR retinas. Both the avascular areas and pathological neovascular tufts were significantly increased in rIL-19–treated OIR retinas and suppressed in IL-19 KO retinas. IL-19 KO mice suppressed expression of ARG1, VEGFA, and pSTAT3. Moreover, BMDMs stimulated by rIL-19 enhanced that expression and suppressed the expression of inducible nitric oxide synthase (iNOS). The proliferation and migration of HRECs were significantly augmented by rIL-19. In addition, intravitreal injection of BMDMs stimulated by rIL-19 enhanced retinal neovascularization.

Conclusions

These findings suggest that IL-19 enhances pathological neovascularization through a direct effect on microvascular endothelial cells and the promotion of M2 macrophage polarization. The inhibition of IL-19 may be a potential treatment for retinal neovascularization.

Co-Targeting Tumor Angiogenesis and Immunosuppressive Tumor Microenvironment: A Perspective in Ethnopharmacology

Tumor angiogenesis is one of the most important processes of cancer deterioration via nurturing an immunosuppressive tumor environment (TME). Targeting tumor angiogenesis has been widely accepted as a cancer intervention approach, which is also synergistically associated with immune therapy. However, drug resistance is the biggest challenge of anti-angiogenesis therapy, which affects the outcomes of anti-angiogeneic agents, and even combined with immunotherapy. Here, emerging targets and representative candidate molecules from ethnopharmacology (including traditional Chinese medicine, TCM) have been focused, and they have been proved to regulate tumor angiogenesis. Further investigations on derivatives and delivery systems of these molecules will provide a comprehensive landscape in preclinical studies. More importantly, the molecule library of ethnopharmacology meets the viability for targeting angiogenesis and TME simultaneously, which is attributed to the pleiotropy of pro-angiogenic factors (such as VEGF) toward cancer cells, endothelial cells, and immune cells. We primarily shed light on the potentiality of ethnopharmacology against tumor angiogenesis, particularly TCM. More research studies concerning the crosstalk between angiogenesis and TME remodeling from the perspective of botanical medicine are awaited.

HIF-1alpha/VEGF pathway mediates 1,3,6,8-tetrabromo-9 H-carbazole-induced angiogenesis: a potential vascular toxicity of an emerging contaminant

The dioxin-like substances polyhalogenated carbazoles (PHCZs) may trigger the aryl hydrocarbon receptor (AhR) signaling pathway. Although the crosstalk between AhR and the hypoxia inducible factor-1 (HIF-1) pathways is generally believed to occur, the exact mechanisms of the HIF-1 pathway in PHCZ toxicity have not been determined. We aimed to elucidate the effect of PHCZs on the HIF-1 pathway and its involvement in the regulation of target genes of HIF-1. Herein, we employed human HepG2 cells transiently transfected with a hypoxia response element (HRE) luciferase reporter to identify PHCZs that could influence HIF-1 pathway. We found that exposure to one of the four selected PHCZs, specifically 1,3,6,8-tetrabromo-9 H-carbazole (1368-BCZ), induced a significant enhancement of the activity of HRE activity. In silico data supported 1368-BCZ-induced HIF-1α activity preferentially. Moreover, 1368-BCZ significantly upregulated the expression of HIF-1 target genes, including endothelial growth factor (VEGF) and erythropoietin. Importantly, the stimulated secretion of VEGF by 1368-BCZ promoted the angiogenesis in human umbilical vein endothelial cells. Therefore, the present experimental and computational studies provide new and direct evidence of 1368-BCZ - HIF-1 interaction, which sheds light on the HIF-mediated cardiovascular toxicity and allows a knowledge-based risk assessment of emerging pollutants.

An internalizing antibody targeting of cell surface GRP94 effectively suppresses tumor angiogenesis of colorectal cancer

Colorectal cancer (CRC) is one of the life-threatening malignancies worldwide. Thus, novel potential therapeutic targets and therapeutics for the treatment of CRC need to be identified to improve the clinical outcomes of patients with CRC. In this study, we found that glucose-regulated protein 94 (GRP94) is overexpressed in CRC tissues, and its high expression is correlated with increased microvessel density. Next, through phage display technology and consecutive in vitro functional isolations, we generated a novel human monoclonal antibody that specifically targets cell surface GRP94 and shows superior internalizing activity comparable to trastuzumab. We found that this antibody specifically inhibits endothelial cell tube formation and simultaneously promotes the downregulation of GRP94 expression on the endothelial cell surface. Finally, we demonstrated that this antibody effectively suppresses tumor growth and angiogenesis of HCT116 human CRC cells without causing severe toxicity in vivo. Collectively, these findings suggest that cell surface GRP94 is a novel potential anti-angiogenic target in CRC and that antibody targeting of GRP94 on the endothelial cell surface is an effective strategy to suppress CRC tumor angiogenesis.

Optimized Methods for Analytical and Functional Comparison of Biosimilar mAb Drugs: A Case Study for Avastin, Mvasi, and Zirabev

Bevacizumab is a humanized therapeutic monoclonal antibody used to reduce angiogenesis, a hallmark of cancer, by binding to VEGF-A. Many pharmaceutical companies have developed biosimilars of Bevacizumab in the last decade. The official reports provided by the FDA and EMA summarize the analytical performance of biosimilars as compared to the originators without giving detailed analytical procedures. In the current study, several key methods were optimized and reported for analytical and functional comparison of bevacizumab originators (Avastin, Altuzan) and approved commercial biosimilars (Zirabev and Mvasi). This case study presents a comparative analysis of a set of biosimilars under optimized analytical conditions for the first time in the literature. The chemical structure of all products was analyzed at intact protein and peptide levels by high-resolution mass spectrometry; the major glycoforms and posttranslational modifications, including oxidation, deamidation, N-terminal PyroGlu addition, and C-terminal Lys clipping, were compared. The SPR technique was used to reveal antigen and some receptor binding kinetics of all products, and the ELISA technique was used for C1q binding affinity analysis. Finally, the inhibition performance of the samples was evaluated by an MTS-based proliferation assay in vitro. Major glycoforms were similar, with minor differences among the samples. Posttranslational modifications, except C-terminal Lys, were determined similarly, while unclipped Lys percentage was higher in Zirabev. The binding kinetics for VEGF, FcRn, FcγRIa, and C1q were similar or in the value range of originators. The anti-proliferative effect of Zirabev was slightly higher than the originators and Mvasi. The analysis of biosimilars under the same conditions could provide a new aspect to the literature in terms of the applied analytical techniques. Further studies in this field would be helpful to better understand the inter-comparability of the biosimilars.

The prognostic value of baseline hematological parameters of peripheral blood in metastatic gastric cancer treated with apatinib

Background: There is strong evidence that apatinib is effective in the treatment of third- or later-line advanced metastatic gastric cancer (mGC). Hematology prediction index is a convenient and cheap method to predict the prognosis of disease. However, the prognosis of baseline hematological parameters of peripheral blood, such as neutrophil-to-lymphocyte ratio (NLR), carbohydrate antigen 125 (CA125) and albumin (ALB) on mGC treated with apatinib have not been identified.

Methods: We retrospectively analyzed mGC received apatinib between 1 January 2014 and 30 June 2021. Survival analyses were performed using the Kaplan-Meier method and Cox-proportional hazards model.

Results: A total of 117 patients were included in this study. The cutoff value of NLR, CA125 and ALB was 2.25, 19.24 U/ml and 37.60 g/L, respectively. The disease control rates (DCR) in the high and low NLR groups were 52.94% and 73.47% (P=0.024); 48.28% and 74.58% (P=0.003) in high and low CA125 groups; 72.97% and 41.86% (P=0.001) in high and low ALB groups. By survival analysis, increasing NLR (P=0.003), CA125 (P<0.001) and decreasing ALB (P<0.001) predicted a shorter PFS after apatinib. NLR (P=0.015), CA125 (P=0.004) and ALB (P=0.005) were significantly predictors for PFS in mGC treated with aptinib.

Conclusion: Increasing NLR, CA125 and decreasing ALB were associated with poorer clinical efficiency and prognosis after apatinib treatment.

CLEC14A was up-regulated in hepatocellular carcinoma and may function as a potential diagnostic biomarker

OBJECTIVE

The current work aimed to investigate the expression and potential clinical significance of C-type Lectin domain family 14 (CLEC14A) in hepatocellular carcinoma.

METHODS

The relative expressions of CLEC14A in the Hepatocellular Carcinoma (HCC) tissue and adjacent normal tissue of 105 HCC patients were examined using RT-qPCR methods. Furthermore, Receiver Operating Characteristic (ROC) curve was drawn for exploring the diagnostic value of CLEC14A. Next, the expressions of CLEC14A in HCC cell lines and normal liver epithelial cells were compared, and the effects of knockdown of CLEC14A on the growth and apoptosis of HCC cells were examined.

RESULTS

The authors found that the expression of CLEC14A was markedly increased in hepatocellular carcinoma tumors in comparison with the adjacent tissue, and the expression level of CLEC14A was positively correlated with the size and differentiation of the tumor. Moreover, results of ROC analysis showed CLEC14A might function as a sensitive diagnostic biomarker for HCC. Furthermore, CLEC14A was up-regulated in HCC cell lines, and transient over-expression of CLEC14A decreased the proliferation and increased the apoptosis of HCC cells in vitro.

CONCLUSIONS

Our results suggested that CLEC14A was up-regulated in HCC and might function as a potential diagnostic marker.

Application of vascular endothelial cells in stem cell medicine

Stem cell medicine is gaining momentum in the development of therapy for various end-stage diseases. The search for new seed cells and exploration of their application prospects are topics of interest in stem cell medicine. In recent years, vascular endothelial cells (VECs) have attracted wide attention from scholars. VECs, which form the inner lining of blood vessels, are critically involved in many physiological functions, including permeability, angiogenesis, blood pressure regulation, immunity, and pathological development, such as atherosclerosis and malignant tumors. VECs have significant therapeutic effects and broad application prospects in stem cell medicine for the treatment of various refractory diseases, including atherosclerosis, myocardial infarction, diabetic complications, hypertension, coronavirus disease 2019, and malignant tumors. On the one hand, VECs and their extracellular vesicles can be directly used for the treatment of these diseases. On the other hand, VECs can be used as therapeutic targets for some diseases. However, there are still some obstacles to the use of VECs in stem cell medicine. In this review, advances in the applications and challenges that come with the use of these cells are discussed.

LINC00337 promotes tumor angiogenesis in colorectal cancer by recruiting DNMT1, which suppresses the expression of CNN1

Colorectal cancer (CRC) is one of the most common human malignancies. An increasing body of evidence has revealed the important roles long noncoding RNA (lncRNA) plays in the growth dynamics of CRC cells. In this study, we aimed to define the role of LINC00337 in the malignant phenotypes, especially angiogenesis, of CRC and clarify the underlying molecular basis. Bioinformatic analyses identified promoter region methylation of CNN1 in CRC, which was further validated by BSP and MSP assays. Loss- and gain- of function approaches were used to determine the roles of CNN1 and LINC00337 in vitro and in vivo. MTT-based method, Transwell migration/invasion assays, and tube formation assay were adopted to evaluate the cancer cell proliferation, migration/invasion, and proangiogenetic potency respectively in vitro. The tumor growth, microvascular density (MVD) and markers of proliferation (Ki67) and angiogenesis (VEGF) were quantified in nude mice xenografted with CRC cells. It was found that CNN1 downregulation and LINC00337 overexpression occurred in CRC tissues and cells. Besides, the CNN1 promoter region was hypermethylated in CRC. CNN1 overexpression or LINC00337 knockdown restricted CRC cell proliferation, migration/invasion, and proangiogenetic potency in vitro, which was substantiated by the in vivo experiments evidenced by facilitated tumor growth and MVD as well as elevated Ki67 and VEGF. Furthermore, our mechanistic evidence revealed that LINC00337 recruited DNMT1 to the promoter region of CNN1 and restricted the transcription of CNN1. Taken together, this study indicates that LINC00337 facilitates the tumorigenesis and angiogenesis in CRC via recruiting DNMT1 to inhibit the expression of CNN1.

Expression and purification of a recombinant ELRL-MAP30 with dual-targeting anti-tumor bioactivity

MAP30 (Momordica antiviral protein 30kD) is a single-chain Ⅰ-type ribosome inactivating protein with a variety of biological activities, including anti-tumor ability. It was reported that MAP30 would serve as a novel and relatively safe agent for prophylaxis and treatment of liver cancer. To determine whether adding two tumor targeting peptides could improve the antitumor activities of MAP30, we genetically modified MAP30 with an RGD motif and a EGFRi motif, which is a ligand with high affinity for αvβ3 integrins and with high affinity for EGFR. The recombinant protein ELRL-MAP30 (rELRL-MAP30) containing a GST-tag was expressed in E. coli. The rELRL-MAP30 was highly expressed in the soluble fraction after induction with 0.15 mM IPTG for 20 h at 16 °C. The purified rELRL-MAP30 appeared as a band on SDS-PAGE. It was identified by western blotting. Cytotoxicity of recombinant protein to HepG2, MDA-MB-231, HUVEC and MCF-7 cells was detected by MTT analysis. Half maximal inhibitory concentration (IC₅₀) values were 54.64 μg/mL, 70.13 μg/mL, 146 μg/mL, 466.4 μg/mL, respectively. Proliferation inhibition assays indicated that rELRL-MAP30 could inhibit the growth of Human liver cancer cell HepG2 effectively. We found that rELRL-MAP30 significantly induced apoptosis in liver cancer cells, as evidenced by nuclear staining of DAPI. In addition, rELRL-MAP30 induced apoptosis in human liver cancer HepG2 cells by up-regulation of Bax as well as down-regulation of Bcl-2. Migration of cell line were markedly inhibited by rELRL-MAP30 in a dose-dependent manner compared to the recombinant MAP30 (rMAP30). In summary, the fusion protein displaying extremely potent cytotoxicity might be highly effective for tumor therapy.

3D Bioprinted cancer models: Revolutionizing personalized cancer therapy

After cardiovascular disease, cancer is the leading cause of death worldwide with devastating health and economic consequences, particularly in developing countries. Inter-patient variations in anti-cancer drug responses further limit the success of therapeutic interventions. Therefore, personalized medicines approach is key for this patient group involving molecular and genetic screening and appropriate stratification of patients to treatment regimen that they will respond to. However, the knowledge related to adequate risk stratification methods identifying patients who will respond to specific anti-cancer agents is still lacking in many cancer types. Recent advancements in three-dimensional (3D) bioprinting technology, have been extensively used to generate representative bioengineered tumor in vitro models, which recapitulate the human tumor tissues and microenvironment for high-throughput drug screening. Bioprinting process involves the precise deposition of multiple layers of different cell types in combination with biomaterials capable of generating 3D bioengineered tissues based on a computer-aided design. Bioprinted cancer models containing patient-derived cancer and stromal cells together with genetic material, extracellular matrix proteins and growth factors, represent a promising approach for personalized cancer therapy screening. Both natural and synthetic biopolymers have been utilized to support the proliferation of cells and biological material within the personalized tumor models/implants. These models can provide a physiologically pertinent cell-cell and cell-matrix interactions by mimicking the 3D heterogeneity of real tumors. Here, we reviewed the potential applications of 3D bioprinted tumor constructs as personalized in vitro models in anticancer drug screening and in the establishment of precision treatment regimens.

miR-181a, delivered by hypoxic PTC-secreted exosomes, inhibits DACT2 by downregulating MLL3, leading to YAP-VEGF-mediated angiogenesis

Papillary thyroid cancer (PTC) is the most common type of thyroid cancer, and angiogenesis plays critical roles in its recurrence and metastasis. In this study, we investigated the effects of hypoxia-induced exosomal microRNA-181 (miR-181a) from PTC on tumor growth and angiogenesis. Thyroid-cancer-related differentially expressed miR-181a was identified by microarray-based analysis in the Gene Expression Omnibus (GEO) database. We validated that miR-181a was highly expressed in PTC cells and even more so in cells cultured under hypoxic conditions, which also augmented exosome secretion from PTC cells. Exosomes extracted from PTC cells with manipulated miR-181a and mixed-lineage leukemia 3 (MLL3) were subjected to normoxic or hypoxic conditions. Human umbilical vein endothelial cells (HUVECs) were transfected with miR-181a inhibitor/mimic or small interfering RNA (siRNA)-MLL3 or treated with exosomes from hypoxic PTC cells. Hypoxic exosomal miR-181a delivery promoted proliferation and capillary-like network formation in HUVECs. Mechanistically, miR-181a targeted and inhibited MLL3. Furthermore, miR-181a downregulated DACT2 and upregulated YAP and vascular endothelial growth factor (VEGF). Further, hypoxic exosomal miR-181a induced angiogenesis and tumor growth in vivo, which was reversed by hypoxic exosomal miR-181a inhibitor. In conclusion, exosomal miR-181a from hypoxic PTC cells promotes tumor angiogenesis and growth through MLL3 and DACT2 downregulation, as well as VEGF upregulation.

Microbiota-Derived Metabolites, Indole-3-aldehyde and Indole-3-acetic Acid, Differentially Modulate Innate Cytokines and Stromal Remodeling Processes Associated with Autoimmune Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation of the synovial joints. Inflammation, new blood vessel formation (angiogenesis) and bone resorption (osteoclastogenesis) are three key processes involved in the joint damage and deformities of arthritis. Various gut microbiota-derived metabolites are implicated in RA pathogenesis. However, there is barely any information about the impact of two such metabolites, indole-3-aldehyde (IAld) and indole-3-acetic acid (I3AA), on arthritis-related processes. We conducted a comparative analysis of IAld and I3AA using established cell-based models to understand how they might influence RA pathogenesis. Although structurally similar, the bioactivities of these two metabolites were profoundly different. IAld but not I3AA, inhibited the expression of pro-inflammatory cytokines (IL-1β and IL-6) in RAW 264.7 (RAW) cells stimulated with heat-killed M. tuberculosis sonicate (Mtb) and lipopolysaccharide (LPS). IAld also exhibited pro-angiogenic activity and pro-osteoclastogenic activity. In contrast, I3AA exhibited anti-angiogenic activity on endothelial cell tube formation but had no effect on osteoclastogenesis. Both IAld and I3AA have been proposed as aryl hydrocarbon receptor (AhR) agonists. Use of CH-223191, an inhibitor of the AhR, suppressed the anti-angiogenic activity of I3AA but failed to mitigate the effects of IAld. Further investigation of the anti-inflammatory activities of IAld and I3AA in LPS-treated RAW cells indicated that inhibition of MyD88-dependent activation of NF-κB and MAPK pathways was not likely involved. Our results suggest that the relative bioavailability of these indole derivatives may differentially impact RA progression and possibly other diseases that share similar cellular processes.

Proteomics-based screening of the endothelial heparan sulfate interactome reveals that C-type lectin 14a (CLEC14A) is a heparin-binding protein

Animal cells express heparan sulfate proteoglycans that perform many important cellular functions by way of heparan sulfate-protein interactions. The identification of membrane heparan sulfate-binding proteins is challenging because of their low abundance and the need for extensive enrichment. Here, we report a proteomics workflow for the identification and characterization of membrane-anchored and extracellular proteins that bind heparan sulfate. The technique is based on limited proteolysis of live cells in the absence of denaturation and fixation, heparin-affinity chromatography, and high-resolution LC-MS/MS, and we designate it LPHAMS. Application of LPHAMS to U937 monocytic and primary murine and human endothelial cells identified 55 plasma membrane, extracellular matrix, and soluble secreted proteins, including many previously unidentified heparin-binding proteins. The method also facilitated the mapping of the heparin-binding domains, making it possible to predict the location of the heparin-binding site. To validate the discovery feature of LPHAMS, we characterized one of the newly-discovered heparin-binding proteins, C-type lectin 14a (CLEC14A), a member of the C-type lectin family that modulates angiogenesis. We found that the C-type lectin domain of CLEC14A binds one-to-one to heparin with nanomolar affinity, and using molecular modeling and mutagenesis, we mapped its heparin-binding site. CLEC14A physically interacted with other glycosaminoglycans, including endothelial heparan sulfate and chondroitin sulfate E, but not with neutral or sialylated oligosaccharides. The LPHAMS technique should be applicable to other cells and glycans and provides a way to expand the repertoire of glycan-binding proteins for further study.

A sequential targeting nanoplatform for anaplastic thyroid carcinoma theranostics

Effective accumulation of nanoparticles (NPs) in tumor regions is one of the major motivations in nanotechnology research and that the establishment of an efficient targeting nanoplatform for the treatment of malignant tumors is urgently needed for theranostic applications. In this study, we engineered multifunctional sequential targeting NPs for achieving synergistic antiangiogenic photothermal therapy (PTT) and multimodal imaging-guided diagnosis for anaplastic thyroid carcinoma (ATC) theranostics. Antibody bevacizumab with an affinity towards vascular endothelial growth factor (VEGF) on the tumor cell surface was conjugated onto the surface of polymer NPs for VEGF targeting and antiangiogenic therapy. Encapsulated IR825 was employed as a photothermal agent (PTA) with a mitochondrial targeting capability, which further cascades NPs into mitochondria to enhance hyperthermic efficiency in the ablation of tumor cells. Importantly, the combination of bevacizumab and IR825 in a single nanosystem achieved desirable accumulations of NPs and that sequential targeted PTT combined with antiangiogenesis significantly promoted the therapeutic efficiency in eradicating tumors by near-infrared (NIR) laser irradiation. Furthermore, these NPs are extraordinary contrast agents for photoacoustic, ultrasound and fluorescence imaging applications, providing multimodal imaging capabilities for therapeutic monitoring and a precise diagnosis. Therefore, this multifunctional nanoplatform provides a promising theranostic strategy for extremely malignant ATC. STATEMENT OF SIGNIFICANCE: Anaplastic thyroid carcinoma (ATC), with extremely aggressive behavior, lacks a satisfactory therapeutic method and a comprehensive early diagnostic strategy. Herein, we successfully synthesized a sequential targeting nanoplatform (IR825@Bev-PLGA-PFP NPs) with theranostic function, which specifically binds to VEGF on the tumor cell surface and further cascades into mitochondria to achieve effective accumulation of NPs in the tumor regions. As a result, it solves the urgent demand for ATC detection and therapy. By breaking the limitation of traditional target, such as low efficacy and frequent recurrence as the results of low accumulation, sequential targeting combined with synergistic antiangiogenic PTT completely eradicates tumors without any residual tissue and side effect. Therefore, this strategy paves a solid way for further investigation in the theranostic progressing of ATC.

C-type lectin family XIV members and angiogenesis

The growth and metastasis of tumors is dependent on angiogenesis. C-type lectins are carbohydrate-binding proteins with a diverse range of functions. The C-type lectin family XIV members are transmembrane glycoproteins, and all four members of this family have been reported to regulate angiogenesis, although the detailed mechanism of action has yet to be completely elucidated. They interact with extracellular matrix proteins and mediate cell-cell adhesion by their lectin-like domain. The aim of the present study was to summarize the available information on the function and mechanism of C-type lectin family XIV in angiogenesis and discuss their potential as targets for cancer therapy.

C-type lectin domain group 14 proteins in vascular biology, cancer and inflammation

The C‐type lectin domain (CTLD) group 14 family of transmembrane glycoproteins consist of thrombomodulin, CD93, CLEC14A and CD248 (endosialin or tumour endothelial marker‐1). These cell surface proteins exhibit similar ectodomain architecture and yet mediate a diverse range of cellular functions, including but not restricted to angiogenesis, inflammation and cell adhesion. Thrombomodulin, CD93 and CLEC14A can be expressed by endothelial cells, whereas CD248 is expressed by vasculature associated pericytes, activated fibroblasts and tumour cells among other cell types. In this article, we review the current literature of these family members including their expression profiles, interacting partners, as well as established and speculated functions. We focus primarily on their roles in the vasculature and inflammation as well as their contributions to tumour immunology. The CTLD group 14 family shares several characteristic features including their ability to be proteolytically cleaved and engagement of some shared extracellular matrix ligands. Each family member has strong links to tumour development and in particular CD93, CLEC14A and CD248 have been proposed as attractive candidate targets for cancer therapy.

Relative Contribution of Framework and CDR Regions in Antibody Variable Domains to Multimerisation of Fv- and scFv-Containing Bispecific Antibodies

Bispecific antibodies represent an emerging class of antibody drugs that are commonly generated by fusion of Fv or scFv antigen binding domains to IgG or Fab scaffolds. Fv- or scFv-mediated multimerisation of bispecific antibodies via promiscuous vH-vL pairing can result in sub-optimal monomer levels during expression, and hence, undesirable therapeutic protein yields. We investigate the contribution of disulphide stabilised Fv and scFv to Fab-Fv and Fab-scFv multimerisation. We show that monomer levels of isolated Fv/scFv cannot always be used to predict monomer levels of Fab-linked Fv/scFv, and that Fab-scFv monomer levels are greater than the equivalent Fab-Fv. Through grafting bispecifics with framework/CDR-‘swapped’ Fv and scFv, we show that monomer levels of disulphide stabilised Fab-Fv and Fab-scFv can be improved by Fv framework ‘swapping’. The Fab-Fv and Fab-scFv can be considered representative of the significant number of bispecific antibody formats containing appended Fv/scFv, as we also used Fv framework ‘swapping’ to increase the monomer level of an IgG-scFv bispecific antibody. This research may, therefore, be useful for maximising the monomeric yield of numerous pharmaceutically-relevant bispecific formats in pre-clinical development.

Overexpression of CLEC18B Associates With the Proliferation, Migration, and Prognosis of Glioblastoma

C-type lectin domain family 18 member B (CLEC18B), encoding a superfamily of CLEC, has been found to be expressed in some of cancer cells, which possibly indicates it associated with cancer. However, the defined functional characterizations of CLEC18B in glioblastoma multiforme (GBM) progression still remain unclear. To this end, clinical relevance of CLEC18B expression with GBM patients’ prognosis was analyzed both in The Cancer Genome Atlas dataset of 174 tissues and 40 GBM tumor tissues collected from our hospital by using the Kaplan–Meier survival and the Cox proportional hazard model. The role of CLEC18B in GBM was determined by loss-of-function assay using small interfering RNA approach in vitro. Functional and signaling analyses were also performed to understand how CLEC18B facilitated the aggressiveness of GBM at molecular and cellular levels using Cell Counting Kit-8 assay, wound-healing, transwell, and Western blot analyses. Results from our analyses showed that CLEC18B was markedly elevated in both GBM tissues and cells, and exhibited strong inverse correlation with overall survival in GBM patients. Moreover, CLEC18B was identified as an independent predictor of patient survival. Functionally, knockdown of CLEC18B inhibited the growth, migration, and invasion of GBM cells. Mechanistic studies revealed that silencing of CLEC18B resulted in downregulation of Wnt/β-catenin signaling activity. Collectively, our findings provide clinical, molecular, and cellular evidence of CLEC18B as a promising prognostic biomarker and therapeutic target for GBM.

A Review of Anti-Angiogenic Targets for Monoclonal Antibody Cancer Therapy. Int J Mol Sci. 2017;18. [PMID: 28817103 PMCID: PMC5578174 DOI: 10.3390/ijms18081786]

Tumor angiogenesis is a key event that governs tumor progression and metastasis. It is controlled by the complicated and coordinated actions of pro-angiogenic factors and their receptors that become upregulated during tumorigenesis. Over the past several decades, vascular endothelial growth factor (VEGF) signaling has been identified as a central axis in tumor angiogenesis. The remarkable advent of recombinant antibody technology has led to the development of bevacizumab, a humanized antibody that targets VEGF and is a leading clinical therapy to suppress tumor angiogenesis. However, despite the clinical efficacy of bevacizumab, its significant side effects and drug resistance have raised concerns necessitating the identification of novel drug targets and development of novel therapeutics to combat tumor angiogenesis. This review will highlight the role and relevance of VEGF and other potential therapeutic targets and their receptors in angiogenesis. Simultaneously, we will also cover the current status of monoclonal antibodies being developed to target these candidates for cancer therapy.