Targeting tumor micro-environment for design and development of novel anti-angiogenic agents arresting tumor growth. Prog Biophys Mol Biol. 2013;113:333-354. [PMID: 24139944 DOI: 10.1016/j.pbiomolbio.2013.10.001]

The application of nanoparticles-based ferroptosis, pyroptosis and autophagy in cancer immunotherapy

Immune checkpoint blockers (ICBs) have been applied for cancer therapy and achieved great success in the field of cancer immunotherapy. Nevertheless, the broad application of ICBs is limited by the low response rate. To address this issue, increasing studies have found that the induction of immunogenic cell death (ICD) in tumor cells is becoming an emerging therapeutic strategy in cancer treatment, not only straightly killing tumor cells but also enhancing dying cells immunogenicity and activating antitumor immunity. ICD is a generic term representing different cell death modes containing ferroptosis, pyroptosis, autophagy and apoptosis. Traditional chemotherapeutic agents usually inhibit tumor growth based on the apoptotic ICD, but most tumor cells are resistant to the apoptosis. Thus, the induction of non-apoptotic ICD is considered to be a more efficient approach for cancer therapy. In addition, due to the ineffective localization of ICD inducers, various types of nanomaterials have been being developed to achieve targeted delivery of therapeutic agents and improved immunotherapeutic efficiency. In this review, we briefly outline molecular mechanisms of ferroptosis, pyroptosis and autophagy, as well as their reciprocal interactions with antitumor immunity, and then summarize the current progress of ICD-induced nanoparticles based on different strategies and illustrate their applications in the cancer therapy.

Expression of PTGS2 along with genes regulating VEGF signalling pathway and association with high-risk factors in locally advanced oral squamous cell carcinoma

BACKGROUND

PTGS2 encodes cyclooxygenase-2 (COX-2), which catalyses the committed step in prostaglandin synthesis. Various in vivo and in vitro data suggest that COX-2 mediates the VEGF signalling pathway. In silico analysis performed in TCGA, PanCancer Atlas for head and neck cancers, demonstrated significant expression and co-expression of PTGS2 and genes that regulate VEGF signalling. This study was designed to elucidate the expression pattern of PTGS2 and genes regulating VEGF signalling in patients with locally advanced oral squamous cell carcinoma (OSCC).

METHODOLOGY

Tumour and normal tissue samples were collected from patients with locally advanced OSCC. RNA was isolated from tissue samples, followed by cDNA synthesis. The cDNA was used for gene expression analysis (RT-PCR) using target-specific primers. The results obtained were compared with the in silico gene expression of the target genes in the TCGA datasets. Co-expression analysis was performed to establish an association between PTGS2 and VEGF signalling genes.

RESULTS

Tumour and normal tissue samples were collected from 24 OSCC patients. Significant upregulation of PTGS2 expression was observed. Furthermore, VEGFA, KDR, CXCR1 and CXCR2 were significantly upregulated in tumour samples compared with paired normal samples, except for VEGFB, whose expression was not statistically significant. A similar expression pattern was observed in silico, except for CXCR2 which was highly expressed in the normal samples. Co-expression analysis showed a significant positive correlation between PTGS2 and VEGF signalling genes, except for VEGFB which showed a negative correlation.

CONCLUSION

PTGS2 and VEGF signalling genes are upregulated in OSCC, which has a profound impact on clinical outcomes.

Changing landscape of anti-angiogenic therapy: Novel approaches and clinical perspectives

Targeting angiogenesis has remained one of the important aspects in disease biology in general and cancer in particular. Currently (June 2023), over 593 clinical trials have been registered at ClinicalTrials.gov having inference of term 'angiogenesis'. A panel of 14 anti-angiogenic drugs have been approved by FDA for the treatment of variety of cancers and other human ailments. Although the anti-angiogenic therapy (AAT) has gained significant clinical attention as a promising approach in the treatment of various diseases, particularly cancer, however, sizable literature has accumulated in the recent past describing the aggressive nature of tumours after the drug holidays, evolving drug resistance and off-target toxicities. Nevertheless, the emergence of inscrutable compensatory or alternative angiogenic mechanisms is limiting the efficacy of anti-angiogenic drugs and focussing the therapeutic regime as a puzzle of 'Lernaean hydra'. This review offers an overview of recent updates on the efficacy of antiangiogenic therapy and the current clinical performance of aaRTK inhibitors. Additionally, it also explores the changing application landscape of AAT, focusing on its role in diabetic nephropathy, age-related macular degeneration and other neovascular ocular disorders. Combination therapy with antiangiogenic drugs and immune check point inhibitors (ICIs) has emerged as a potential strategy to enhance the therapeutic index of cancer immunotherapy. While clinical studies have demonstrated the clinical efficacy of this approach, they also highlight the complex and sometimes unpredictable adverse events associated with it. Normalizing tumour vasculature has been identified as a key factor in unlocking the full potential of ICIs, thereby providing hope for improved treatment outcomes. The future prospects and challenges of AAT have been described with special reference to integration of technological advances for enhancing its efficacy and applications beyond its discovery.

Sequential-delivery nanocomplex for combined anti-angiogenesis and gene therapy against colorectal cancer

Neovascularization can provide tumors with essential nutrients and oxygen, as well as maintain a microenvironment for tumor cell growth. In this study, we combined anti-angiogenic therapy and gene therapy for synergistic anti-tumor therapy. We co-delivered the vascular endothelial growth factor receptor inhibitor fruquintinib (Fru) and small interfering RNA CCAT1 (siCCAT1) inhibiting epithelial-mesenchymal transition using 1,2-distearoyl-snglycero-3-phosphoethanolamine-N- [methoxy (polyethylene glycol)] with a pH-responsive benzoic imine linker bond (DSPE-Hyd-mPEG) and polyethyleneimine-poly (d, l-lactide) (PEI-PDLLA) nanocomplex (Fru and siCCAT1 co-delivery NP, FCNP). Due to the characteristics of pH-response, DSPE-Hyd-mPEG removed from FCNP after enrichment at the tumor site, which had a protective effect in the body. Meanwhile, Fru acting on the peritumor blood vessels was rapidly released, and then the nanoparticles loaded with siCCAT1 (CNP) was engulfed by cancer cells and facilitate the successful lysosomal escape of siCCAT1 in, playing the role of silencing CCAT1. Efficient silencing of CCAT1 by FCNP was observed, and simultaneously, the expression of VEGFR-1 was also down-regulated. Furthermore, FCNP elicited significant synergistic antitumor efficacy via anti-angiogenesis and gene therapy in the SW480 subcutaneous xenograft model with favorable biosafety and biocompatibility during the treatment. Overall, FCNP was considered a promising strategy for the combined anti-angiogenesis-gene treatment against colorectal cancer.

Chaperone-mediated autophagy promotes breast cancer angiogenesis via regulation of aerobic glycolysis

Evidence shows that chaperone-mediated autophagy (CMA) is involved in cancer cell pathogenesis and progression. However, the potential role of CMA in breast cancer angiogenesis remains unknown. We first manipulated CMA activity by knockdown and overexpressing of lysosome-associated membrane protein type 2A (LAMP2A) in MDA-MB-231, MDA-MB-436, T47D and MCF7 cells. We found that the tube formation, migration and proliferation abilities of human umbilical vein endothelial cells (HUVECs) were inhibited after cocultured with tumor-conditioned medium from breast cancer cells of LAMP2A knockdown. While the above changes were promoted after cocultured with tumor-conditioned medium from breast cancer cells of LAMP2A overexpression. Moreover, we found that CMA could promote VEGFA expression in breast cancer cells and in xenograft model through upregulating lactate production. Finally, we found that lactate regulation in breast cancer cells is hexokinase 2 (HK2) dependent, and knockdown of HK2 can significantly reduce the ability of CMA-mediated tube formation capacity of HUVECs. Collectively, these results indicate that CMA could promote breast cancer angiogenesis via regulation of HK2-dependent aerobic glycolysis, which may serve as an attractive target for breast cancer therapies.

Telocytes and endometriosis

Endometriosis involving the presence and growth of glands and stroma outside the uterine cavity is a common, inflammatory, benign gynecologic disease. Nevertheless, no single theory can exactly account for the pathogenesis of endometriosis. Telocytes, a kind of novel mesenchymal cells, have been suggested to be crucial in promoting angiogenesis and increasing the activity of endometrial interstitial cells and inflammatory cells. Given above roles, telocytes may be considered as the possible pathogenesis of endometriosis. We reviewed the current literature on telocytes. The following aspects were considered: (A) the telocytes' typical characteristics, function, and morphological changes in endometriosis; (B) the potential role of telocytes in endometriosis by impacting the inflammation, invasion, and angiogenesis; (C) telocytes as the potential treatment options for endometriosis.

An overview of kinin mediated events in cancer progression and therapeutic applications

Kinins are bioactive peptides generated in the inflammatory milieu of the tissue microenvironment, which is involved in cancer progression and inflammatory response. Kinins signals through activation of two G-protein coupled receptors; inducible Bradykinin Receptor B1 (B1R) and constitutive receptor B2 (B2R). Activation of kinin receptors and its cross-talk with receptor tyrosine kinases activates multiple signaling pathways, including ERK/MAPK, PI3K, PKC, and p38 pathways regulating cancer hallmarks. Perturbations of the kinin-mediated events are implicated in various aspects of cancer invasion, matrix remodeling, and metastasis. In the tumor microenvironment, kinins initiate fibroblast activation, mesenchymal stem cell interactions, and recruitment of immune cells. Albeit the precise nature of kinin function in the metastasis and tumor microenvironment are not completely clear yet, several kinin receptor antagonists show anti-metastatic potential. Here, we showcase an overview of the complex biology of kinins and their role in cancer pathogenesis and therapeutic aspects.

Effects of Maternal Nutrient Restriction and Melatonin Supplementation on Cardiomyocyte Cell Development Parameters Using Machine Learning Techniques

The objective of the current study was to examine the effects of maternal feed restriction and melatonin supplementation on fetal cardiomyocyte cell development parameters and predict binucleation and hypertrophy using machine learning techniques using pregnant beef heifers. Brangus heifers (n = 29) were assigned to one of four treatment groups in a 2 × 2 factorial design at day 160 of gestation: (1) 100% of nutrient requirements (adequately fed; ADQ) with no dietary melatonin (CON); (2) 100% of nutrient requirements (ADQ) with 20 mg/d of dietary melatonin (MEL); (3) 60% of nutrient requirements (nutrient-restricted; RES) with no dietary melatonin (CON); (4) 60% of nutrient requirements (RES) with 20 mg/d of dietary melatonin (MEL). On day 240 of gestation, fetuses were removed, and fetal heart weight and thickness were determined. The large blood vessel perimeter was increased in fetuses from RES compared with ADQ (p = 0.05). The total number of capillaries per tissue area exhibited a nutrition by treatment interaction (p = 0.01) where RES-MEL increased capillary number compared (p = 0.03) with ADQ-MEL. The binucleated cell number per tissue area showed a nutrition by treatment interaction (p = 0.010), where it was decreased in RES-CON vs. ADQ-CON fetuses. Hypertrophy was estimated by dividing ventricle thickness by heart weight. Based on machine learning results, for the binucleation and hypertrophy target variables, the Bagging model with 5 Decision Tree estimators and 3 Decision Tree estimators produced the best results without overfitting. In the prediction of binucleation, left heart ventricular thickness feature had the highest Gin importance weight followed by fetal body weight. In the case of hypertrophy, heart weight was the most important feature. This study provides evidence that restricted maternal nutrition leads to a reduction in the number of cardiomyocytes while melatonin treatment can mitigate some of these disturbances.

Adapt to Persist: Glioblastoma Microenvironment and Epigenetic Regulation on Cell Plasticity

Glioblastoma (GBM) is the most frequent and aggressive brain tumor, characterized by great resistance to treatments, as well as inter- and intra-tumoral heterogeneity. GBM exhibits infiltration, vascularization and hypoxia-associated necrosis, characteristics that shape a unique microenvironment in which diverse cell types are integrated. A subpopulation of cells denominated GBM stem-like cells (GSCs) exhibits multipotency and self-renewal capacity. GSCs are considered the conductors of tumor progression due to their high tumorigenic capacity, enhanced proliferation, invasion and therapeutic resistance compared to non-GSCs cells. GSCs have been classified into two molecular subtypes: proneural and mesenchymal, the latter showing a more aggressive phenotype. Tumor microenvironment and therapy can induce a proneural-to-mesenchymal transition, as a mechanism of adaptation and resistance to treatments. In addition, GSCs can transition between quiescent and proliferative substates, allowing them to persist in different niches and adapt to different stages of tumor progression. Three niches have been described for GSCs: hypoxic/necrotic, invasive and perivascular, enhancing metabolic changes and cellular interactions shaping GSCs phenotype through metabolic changes and cellular interactions that favor their stemness. The phenotypic flexibility of GSCs to adapt to each niche is modulated by dynamic epigenetic modifications. Methylases, demethylases and histone deacetylase are deregulated in GSCs, allowing them to unlock transcriptional programs that are necessary for cell survival and plasticity. In this review, we described the effects of GSCs plasticity on GBM progression, discussing the role of GSCs niches on modulating their phenotype. Finally, we described epigenetic alterations in GSCs that are important for stemness, cell fate and therapeutic resistance.

The potential role of exosomal circRNAs in the tumor microenvironment: insights into cancer diagnosis and therapy

Exosomes are multifunctional regulators of intercellular communication by carrying various messages under both physiological and pathological status of cancer patients. Accumulating studies have identified the presence of circular RNAs (circRNAs) in exosomes with crucial regulatory roles in diverse pathophysiological processes. Exosomal circRNAs derived from donor cells can modulate crosstalk with recipient cells locally or remotely to enhance cancer development and propagation, and play crucial roles in the tumor microenvironment (TME), leading to significant enhancement of tumor immunity, metabolism, angiogenesis, drug resistance, epithelial mesenchymal transition (EMT), invasion and metastasis. In this review, we describe the advances of exosomal circRNAs and their roles in modulating cancer hallmarks, especially those in the TME. Moreover, clinical application potential of exosomal circRNAs in cancer diagnosis and therapy are highlighted, bridging the gap between basic knowledge and clinical practice.

Design, synthesis and anti-tumor evaluation of 1,2,4-triazol-3-one derivatives and pyridazinone derivatives as novel CXCR2 antagonists

Chemokine receptor 2 (CXCR2) is the receptor of glutamic acid-leucine-arginine sequence-contained chemokines CXCs (ELR⁺ CXCs). In recent years, CXCR2-target treatment strategy has come a long way in cancer therapy. CXCR2 antagonists could block CXCLs/CXCR2 axis, and are widely used in regulating immune cell migration, tumor metastasis, apoptosis and angiogenesis. Herein, two series of new CXCR2 small-molecule inhibitors, including 1,2,4-triazol-3-one derivatives 1-11 and pyridazinone derivatives 12-22 were designed and synthesized based on the proof-to-concept. The pyridazinone derivative 18 exhibited good CXCR2 antagonistic activity (69.4 ± 10.5 %Inh at 10 μM) and demonstrated its significant anticancer metastasis activity in MDA-MB-231 cells and remarkable anti-angiogenesis activity in HUVECs. Furthermore, noteworthy was that 18 exhibited an obvious synergistic effect with Sorafenib in anti-proliferation assay in MDA-MB-231 cells. Moreover, 18 showed a distinct reduction of the phosphorylation levels of both PI3K and AKT proteins in MDA-MB-231 cells, and also affected the expression levels of other PI3K/AKT signaling pathway-associated proteins. The molecular docking studies of 18 with CXCR2 also verified the rationality of our design strategy. All of these results revealed pyridazinone derivative 18 as a promising CXCR2 antagonist for future cancer therapy.

The Heparan Sulfate Binding Peptide in Tumor Progression of Triple-Negative Breast Cancer

Angiogenesis is the formation of new vessels from pre-existing vasculature. The heparan sulfate chains from endothelial cell proteoglycans interact with the major angiogenic factors, regulating blood vessels´ formation. Since the FDA´s first approval, anti-angiogenic therapy has shown tumor progression inhibition and increased patient survival. Previous work in our group has selected an HS-binding peptide using a phage display system. Therefore, we investigated the effect of the selected peptide in angiogenesis and tumor progression. The HS-binding peptide showed a higher affinity for heparin N-sulfated. The HS-binding peptide was able to inhibit the proliferation of human endothelial umbilical cord cells (HUVEC) by modulation of FGF-2. It was verified a significant decrease in the tube formation of human endothelial cells and capillary formation of mice aorta treated with HS-binding peptide. HS-binding peptide also inhibited the formation of sub-intestinal blood vessels in zebrafish embryos. Additionally, in zebrafish embryos, the tumor size decreased after treatment with HS-binding peptide.

Synthesis and evaluation of N-(4-(substituted)-3-(trifluoromethyl) phenyl) isobutyramides and their N-ethyl analogous as anticancer, anti-angiogenic & antioxidant agents: In vitro and in silico analysis

N-(4-(substituted)-3-(trifluoromethyl) phenyl) isobutyramides and their N-ethyl analogues (flutamides) are versatile scaffolds with a wide spectrum of biological activities. A series of new N-(4-(substituted)-3-(trifluoromethyl) phenyl) isobutyramides (8a-t) and their N-ethyl analogous (9a-t) were synthesized and characterized. The inhibitory potential of the synthesized compounds on the viability of three human cancer cell lines HEP3BPN 11 (liver), MDA-MB 453 (breast), and HL 60 (leukemia) were assessed. Among all the compounds 8 L, 8q, 9n and 9p showed higher inhibitory activity on the viability of HL 60 than the standard methotrexate. These lead molecules were then tested for their potential to inhibit the activity of proangiogenic cytokines. The compound 9n showed significantly better inhibition against two cytokines viz. TNFα and Leptin as compared to the standard suramin, while 9p has activity comparable to suramin against IGF1, VEGF, FGFb, and Leptin. The 8q is found to be strong antiangiogenic agent against IGF1, VEGF and TGFβ; while 8 L has showed activity against TNFα, VEGF, and Leptin inhibition. Furthermore antioxidant potential of 8a-t and 9a-t compounds was screened using DPPH, OH and SOR radical scavenging activities. The OH radical scavenging activity of 8c and DPPH activities of 9n as well as 9o are significant as compared to respective standards ascorbic acid and α-tocopherol. The 8c, 9p and 9 h have also exhibited potential antioxidant activity. Additionally, we present in silico molecular docking data to provide the structural rationale of observed TNFα inhibition against newly synthesized compounds. Overall, the synthesized flutamide derivatives have not only anticancer activity, but also possess dual inhibitory effect (anti-angiogenesis and antioxidant) and hence can act as a promising avenue to develop further anticancer agents.

Controlled Delivery of Slit3 Proteins from Alginate Microbeads Inhibits In Vitro Angiogenesis

BACKGROUND

The Slit-Robo pathway is a key regulator of angiogenesis and cellular function in experimental models. Slit3 proteins exhibit both proangiogenic and antiangiogenic properties, but the exact mechanism remains unclear. It is theorized that Slit3 may be a potential treatment for vascular diseases and cancer.

METHODS

Slit3 labeled with I-125 was encapsulated in microbeads composed of low-viscosity alginate of high-glucuronic acid content, first coated with poly-L-ornithine for various durations and finally with low-viscosity high mannuronic acid. Gamma counter was used to measure microbead encapsulation efficiency and Slit3 release. Markers of angiogenesis were assessed with Boyden chamber, scratch wound, and Matrigel tube formation assays using human umbilical vein and mouse endothelial cells.

RESULTS

On incubation of Slit3-loaded microbeads, there was an initial burst phase release of Slit3 for the first 24 h followed by sustained release for 6 to 12 d. Microbead composition determined encapsulation efficiency and rate of release; Slit3 encapsulation was most efficient in microbeads with lower low-viscosity alginate of high-glucuronic acid content concentrations (1.5%) and no poly-L-ornithine coating. Compared with controls (media alone), Slit3 microbeads significantly inhibited in vitro cellular migration, endothelial cell migration for wound closure at 24 and 48 h and endothelial tube formation (P < 0.001, respectively).

CONCLUSIONS

Slit3 can be effectively encapsulated and delivered via a controlled release pattern using alginate microbeads. Microbead encapsulation reduces in vitro endothelial tube formation and inhibits cellular migration to impair angiogenesis. Thus, Slit3 microparticles may be explored as a therapeutic option to mitigate tumor proliferation.

Glycosaminoglycans: Carriers and Targets for Tailored Anti-Cancer Therapy

The tumor microenvironment (TME) is composed of cancerous, non-cancerous, stromal, and immune cells that are surrounded by the components of the extracellular matrix (ECM). Glycosaminoglycans (GAGs), natural biomacromolecules, essential ECM, and cell membrane components are extensively altered in cancer tissues. During disease progression, the GAG fine structure changes in a manner associated with disease evolution. Thus, changes in the GAG sulfation pattern are immediately correlated to malignant transformation. Their molecular weight, distribution, composition, and fine modifications, including sulfation, exhibit distinct alterations during cancer development. GAGs and GAG-based molecules, due to their unique properties, are suggested as promising effectors for anticancer therapy. Considering their participation in tumorigenesis, their utilization in drug development has been the focus of both industry and academic research efforts. These efforts have been developing in two main directions; (i) utilizing GAGs as targets of therapeutic strategies and (ii) employing GAGs specificity and excellent physicochemical properties for targeted delivery of cancer therapeutics. This review will comprehensively discuss recent developments and the broad potential of GAG utilization for cancer therapy.

A Review of Bioactive Peptides: Chemical Modification, Structural Characterization and Therapeutic Applications

In recent years, the development and applications of protein drugs have attracted extensive attention from researchers. However, the shortcomings of protein drugs also limit their further development. Therefore, bioactive peptides isolated or simulated from protein polymers have broad application prospects in food, medicine, biotechnology, and other industries. Such peptides have a molecular weight distribution between 180 and 1000 Da. As a small molecule substance, bioactive peptide is usually degraded by various enzymes in the organism and have a short half-life. At the same time, such substances have poor stability and are difficult to produce and store. Therefore, these active peptides may be modified through phosphorylation, glycosylation, and acylation. Compared with other protein drugs, the modified active peptides are more easily absorbed by the body, have longer half-life, stronger targeting, and fewer side effects in addition to higher bioavailability. In the light of their functions, bioactive peptide can be divided into antimicrobial, anti-tumour, anti-angiogenic, antioxidant, anti-fatigue, and anti-hypertensive peptides. This article mainly focuses on the introduction of several promising biologically active peptides functioning as antimicrobial, anti-tumour, antiangiogenic, and antioxidant peptides from the three aspects modification, structural characteristics and mechanism of action.

Reversine suppresses osteosarcoma cell growth through targeting BMP-Smad1/5/8-mediated angiogenesis

Reversine, or 2-(4-morpholinoanilino)-6cyclohexylaminopurine, is a 2,6-disubstituted purine derivative. This small molecule exhibits tumor-suppressive activities through different molecular mechanisms. In this study, in vitro and in vivo angiogenic models were used to elucidate the effect of Reversine on angiogenesis in the tumor suppression. Firstly, we grafted osteosarcoma-derived MNNG/HOS cell aggregates onto chick embryonic chorioallantoic membrane (CAM) to examine the vascularization of these grafts following Reversine treatment. Following culture, it was determined that Reversine inhibited MNNG/HOS grafts growth, and decreased the density of blood vessels in the chick CAM. We then used CAM and chick embryonic yolk-sac membrane (YSM) to investigate the effects of Reversine on angiogenesis. The results revealed Reversine inhibited the proliferation of endothelial cells, where cells were mainly arrested at G₁/S phase of the cell cycle. Scratch-wound assay with HUVECs revealed that Reversine suppressed cell migration in vitro. Furthermore, endothelial cells tube formation assay and chick aortic arch sprouting assay demonstrated Reversine inhibited the sprouting, migration of endothelial cells. Lastly, qPCR and western blot analyses showed BMP-associated Smad1/5/8 signaling expressions were up-regulated by Reversine treatment. Our results showed that Reversine could suppress tumor growth by inhibiting angiogenesis through BMP signaling, and suggests a potential use of Reversine as an anti-tumor therapy.

Role of platelets and breast cancer stem cells in metastasis

The high mortality rate of breast cancer is mainly caused by the metastatic ability of cancer cells, resistance to chemotherapy and radiotherapy, and tumor regression capacity. In recent years, it has been shown that the presence of breast cancer stem cells is closely associated with the migration and metastatic ability of cancer cells, as well as with their resistance to chemotherapy and radiotherapy. The tumor microenvironment is one of the main molecular factors involved in cancer and metastatic processes development, in this sense it is interesting to study the role of platelets, one of the main communicator cells in the human body which are activated by the signals they receive from the microenvironment and can generate more than one response. Platelets can ingest and release RNA, proteins, cytokines and growth factors. After the platelets interact with the tumor microenvironment, they are called "tumor-educated platelets." Tumor-educated platelets transport material from the tumor microenvironment to sites adjacent to the tumor, thus helping to create microenvironments conducive for the development of primary and metastatic tumors. It has been observed that the clone capable of carrying out the metastatic process is a cancer cell with stem cell characteristics. Cancer stem cells go through a series of processes, including epithelial-mesenchymal transition, intravasation into blood vessels, movement through blood vessels, extravasation at the site of the establishment of a metastatic focus, and site colonization. Tumor-educated platelets support all these processes. 

Targeting neuropilin-1 interactions is a promising anti-tumor strategy

ABSTRACT

Neuropilins (NRP1 and NRP2) are multifunctional receptor proteins that are involved in nerve, blood vessel, and tumor development. NRP1 was first found to be expressed in neurons, but subsequent studies have demonstrated its surface expression in cells from the endothelium and lymph nodes. NRP1 has been demonstrated to be involved in the occurrence and development of a variety of cancers. NRP1 interacts with various cytokines, such as vascular endothelial growth factor family and its receptor and transforming growth factor β1 and its receptor, to affect tumor angiogenesis, tumor proliferation, and migration. In addition, NRP1+ regulatory T cells (Tregs) play an inhibitory role in tumor immunity. High numbers of NRP1+ Tregs were associated with cancer prognosis. Targeting NRP1 has shown promise, and antagonists against NRP1 have had therapeutic efficacy in preliminary clinical studies. NRP1 treatment modalities using nanomaterials, targeted drugs, oncolytic viruses, and radio-chemotherapy have gradually been developed. Hence, we reviewed the use of NRP1 in the context of tumorigenesis, progression, and treatment.

Down syndrome iPSC model: endothelial perspective on tumor development

Trisomy 21 (T21), known as Down syndrome (DS), is a widely studied chromosomal abnormality. Previous studies have shown that DS individuals have a unique cancer profile. While exhibiting low solid tumor prevalence, DS patients are at risk for hematologic cancers, such as acute megakaryocytic leukemia and acute lymphoblastic leukemia. We speculated that endothelial cells are active players in this clinical background. To this end, we hypothesized that impaired DS endothelial development and functionality, impacted by genome-wide T21 alterations, potentially results in a suboptimal endothelial microenvironment with the capability to prevent solid tumor growth.

To test this hypothesis, we assessed molecular and phenotypic differences of endothelial cells differentiated from Down syndrome and euploid iPS cells. Microarray, RNA-Seq, and bioinformatic analyses revealed that most significantly expressed genes belong to angiogenic, cytoskeletal rearrangement, extracellular matrix remodeling, and inflammatory pathways. Interestingly, the majority of these genes are not located on Chromosome 21. To substantiate these findings, we carried out functional assays. The obtained phenotypic results correlated with the molecular data and showed that Down syndrome endothelial cells exhibit decreased proliferation, reduced migration, and a weak TNF-α inflammatory response. Based on this data, we provide a set of genes potentially associated with Down syndrome’s elevated leukemic incidence and its unfavorable solid tumor microenvironment—highlighting the potential use of these genes as therapeutic targets in translational cancer research.

Effects of NRP1 on angiogenesis and vascular maturity in endothelial cells are dependent on the expression of SEMA4D

Angiogenesis and vascular maturation play important roles in tumorigenesis and tumor development. The expression of neuropilin 1 (NRP1) is closely associated with angiogenesis in tumors; however, the molecular mechanisms of action in angiogenesis and tumor maturation, as well as the potential clinical value of NRP1 remain unclear. The importance of NRP1 expression in tumor progression was determined using The Cancer Genome Atlas (TCGA) database analysis. Gain- and loss-of-function experiments of NRP1 were performed in vascular endothelial cells (ECs) to investigate the functions in angiogenesis. CCK-8, flow cytometry, Transwell experiments and a series of in vitro experiments were used to detect cell functions. A combination of angiogenesis antibody arrays and RNA-Seq analyses were performed to reveal the proangiogenic mechanisms of action. The function of semaphorin 4D (SEMA4D) was also investigated separately. NRP1 mRNA levels were significantly increased in primary tumors compared with normal tissues based on TCGA data (P<0.01) and were associated with tumor development in patients. Gain- and loss-of-function experiments highlighted the function of NRP1 in promoting EC proliferation, motility and capillary-like tube formation and in reducing apoptosis. NRP1 overexpression led to significantly decreased EC markers (PECAM-1, angiogenin, PIGF and MMP-9) expression levels and reduced the vascular maturity. MAPK7, TPM1, RRBP1, PTPRK, HSP90A, PRKD2, PFKFB3, RGS4 and SPARC were revealed to play important roles in this process. SEMA4D was revealed to be a key protein associated with NRP1 in ECs. These data indicated that NRP1-promoted angiogenesis may be induced at the cost of reducing maturity of the ECs. NRP1 may also be a therapeutic target for antiangiogenic strategies and a candidate prognostic marker for tumors.

Decreased miR-200b-3p in cancer cells leads to angiogenesis in HCC by enhancing endothelial ERG expression

Transcription factor ERG (erythroblast transformation-specific (ETS)-related gene) is essential in endothelial differentiation and angiogenesis, in which microRNA (miR)-200b-3p targeting site is expected by miRNA target prediction database. miR-200b is known decreased in hepatocellular carcinoma (HCC), however, the functional relation between ERG and miR-200b-3p, originating from pre-miR-200b, in HCC angiogenesis remains unclear. We investigated whether hepatocyte-derived miR-200b-3p governs angiogenesis in HCC by targeting endothelial ERG. Levels of miR-200b-3p in HCC tissues were significantly lower than those in adjacent non-HCC tissues. Poorly differentiated HCC cell line expressed lower level of miR-200b-3p compared to well-differentiated HCC cell lines. The numbers of ERG-positive endothelial cells were higher in HCC tissues than in adjacent non-HCC tissues. There was a negative correlation between the number of ERG-positive cells and miR-200b-3p expression in HCC tissues. Culture supernatants of HCC cell lines with miR-200b-3p-overexpression reduced cell migration, proliferation and tube forming capacity in endothelial cells relative to the control, while those with miR-200b-3p-inhibition augmented the responses. Exosomes isolated from HCC culture supernatants with miR-200b-3p overexpression suppressed endothelial ERG expression. These results suggest that exosomal miR-200b-3p from hepatocytes suppresses endothelial ERG expression, and decreased miR-200b-3p in cancer cells promotes angiogenesis in HCC tissues by enhancing endothelial ERG expression.

Circular RNAs in the tumour microenvironment

BACKGROUND

Circular RNAs (circRNAs) are a new class of endogenous non-coding RNAs (ncRNAs) widely expressed in eukaryotic cells. Mounting evidence has highlighted circRNAs as critical regulators of various tumours. More importantly, circRNAs have been revealed to recruit and reprogram key components involved in the tumour microenvironment (TME), and mediate various signaling pathways, thus affecting tumourigenesis, angiogenesis, immune response, and metastatic progression. In this review, we briefly introduce the biogenesis, characteristics and classification of circRNAs, and describe various mechanistic models of circRNAs. Further, we provide the first systematic overview of the interplay between circRNAs and cellular/non-cellular counterparts of the TME and highlight the potential of circRNAs as prospective biomarkers or targets in cancer clinics. Finally, we discuss the biological mechanisms through which the circRNAs drive development of resistance, revealing the mystery of circRNAs in drug resistance of tumours.

SHORT CONCLUSION

Deep understanding the emerging role of circRNAs and their involvements in the TME may provide potential biomarkers and therapeutic targets for cancer patients. The combined targeting of circRNAs and co-activated components in the TME may achieve higher therapeutic efficiency and become a new mode of tumour therapy in the future.

A 2,3-diphenylpyrido[1,2-a] pyrimidin-4-one derivative inhibits specific angiogenic factors induced by TNF-α

Low-grade chronic inflammation is a key process of angiogenesis in tumour progression. We investigated whether a synthetic analogue of apigenin, the 2-(3,4-dimethoxyphenyl)-3-phenyl-4H-pyrido[1,2-a] pyrimidin-4-one (called DB103), interfered with the mechanisms involved in the angiogenic process induced by the inflammatory cytokine tumour necrosis factor (TNFα). In endothelial cells, DB103 but not apigenin reduced the TNFα-induced oxidative stress. DB103 inhibited the activation of ERK1/2 but not JNK, p38 and Akt kinases, while apigenin was not so selective because it inhibited essentially all examined kinases. Similarly, apigenin inhibited the TNFα-induced transcription factors CREB, STAT3, STAT5 and NF-κB, while DB103 acted only on NF-κB. DB103 inhibited the induced-release of angiogenic factors such as monocyte chemotactic protein-1, interleukin-6 (IL-6) and angiopoietin-2 but not IL-8, while apigenin reduced the IL-6 and IL-8 release. DB103 revealed a better ability than apigenin to modulate proangiogenic responses induced by an inflammatory microenvironment.

Effect of laminin environments and tumor factors on the biology of myeloid dendritic cells

Dendritic cells (DCs) are immune cells that surveil the organism for infections or malignancies and activate specific T lymphocytes initiating specific immune responses. Contrariwise, DCs have been show to participate in the development of diseases, among them some types of cancer by inducing angiogenesis or immunosuppression. The ultimate fate of DC functions regarding their role in disease or health is prompted by signals from the microenvironment. We have previously shown that the interaction of DCs with various extracellular matrix components modifies the immune properties and angiogenic potential of these cells. The objective of the current studies was to investigate the angiogenic and immune profile of murine myeloid DCs upon interaction with laminin environments, with a particular emphasis on ovarian cancer. Our results show that murine ovarian tumors produce several types of laminins, as determined by PCR analysis, and also that tumor-associated DCs, both from ascites or solid tumors express adhesion molecules capable of interacting with these molecules as determined by flow cytometry and PCR analysis. Further, we established that DCs cultured on laminin upregulate both AKT and MEK signaling pathways, and that long-term culture on laminin surfaces decreases the immunological capacities of these cells when compared to the same cells cultured on synthetic substrates. In addition, we observed that tumor conditioned media was able to modify the metabolic status of these cells, and also reprogram the development of DCs from bone marrow precursors towards the generation of myeloid-derived suppressor cells. Overall, these studies demonstrate that the interaction between soluble factors and extracellular matrix components of the ovarian cancer microenvironment shape the biology of DCs and thus help them become co-conspirators of tumor growth.

Therapeutic Opportunities in Colorectal Cancer: Focus on Melatonin Antioncogenic Action

Colorectal cancer (CRC) influences individual health worldwide with high morbidity and mortality. Melatonin, which shows multiple physiological functions (e.g., circadian rhythm, immune modulation, and antioncogenic action), can be present in almost all organisms and found in various tissues including gastrointestinal tract. Notably, melatonin disruption is closely associated with the elevation of CRC incidence, indicating that melatonin is effective in suppressing CRC development and progression. Mechanistically, melatonin favors in activating apoptosis and colon cancer immunity, while reducing proliferation, autophagy, metastasis, and angiogenesis, thereby exerting its anticarcinogenic effects. This review highlights that melatonin can be an adjuvant therapy and be beneficial in treating patients suffering from CRC.

Adipose derived stem cells promote tumor metastasis in breast Cancer cells by stem cell factor inhibition of miR20b

Breast cancer (BC) metastasis after surgery is associated with the tumor microenvironment and especially with adipose tissue-derived mesenchymal stem cells (ASCs) that have been shown to promote the BC progression. To better understand the role of ASCs in tumor metastasis, our study explored a novel mechanism that mediates the negative regulation of miR20b during ASC-induced tumor metastasis of BC cells. In this study, we found that the migration and invasion abilities of BC cells are markedly increased coculture with ASCs. By studying the regulatory mechanism, we found that miR20b biogenesis in BC cells can be attenuated by ASC-released stem cell factor (SCF) through the downstream c-Kit/MAPK-p38/E2F1 signaling cascade and that miR-20b acts as a tumor suppressor miRNA in the inhibition of BC migration and invasion. HIF-1α and VEGFA are the target genes of miR20b and miR20b downregulation activated HIF-1α-mediated VEGFA transcription and ASC-induced BC migration and invasion. The upregulation of miR20b abrogated the activation of EMT and lung metastasis of breast cancer cells cocultured with ASCs by the inhibition of N-cadherin, vimentin and Twist expression in vitro and in vivo. Collectively, our findings indicate that downregulation of miR20b by ASCs/SCF activates HIF-1α/VEGFA and induces BC cell EMT and metastasis, suggesting that this process is activated by the p-c-Kit/MAPK-p38/E2F1 pathway.

Flaxseed Lignans as Important Dietary Polyphenols for Cancer Prevention and Treatment: Chemistry, Pharmacokinetics, and Molecular Targets

Cancer causes considerable morbidity and mortality across the world. Socioeconomic, environmental, and lifestyle factors contribute to the increasing cancer prevalence, bespeaking a need for effective prevention and treatment strategies. Phytochemicals like plant polyphenols are generally considered to have anticancer, anti-inflammatory, antiviral, antimicrobial, and immunomodulatory effects, which explain their promotion for human health. The past several decades have contributed to a growing evidence base in the literature that demonstrate ability of polyphenols to modulate multiple targets of carcinogenesis linking models of cancer characteristics (i.e., hallmarks and nutraceutical-based targeting of cancer) via direct or indirect interaction or modulation of cellular and molecular targets. This evidence is particularly relevant for the lignans, an ubiquitous, important class of dietary polyphenols present in high levels in food sources such as flaxseed. Literature evidence on lignans suggests potential benefit in cancer prevention and treatment. This review summarizes the relevant chemical and pharmacokinetic properties of dietary polyphenols and specifically focuses on the biological targets of flaxseed lignans. The consolidation of the considerable body of data on the diverse targets of the lignans will aid continued research into their potential for use in combination with other cancer chemotherapies, utilizing flaxseed lignan-enriched natural products.

The use of crevicular fluid to assess markers of inflammation and angiogenesis, IL-17 and VEGF, in patients with solid tumors receiving zoledronic acid and/or bevacizumab

PURPOSE

Crevicular fluid was used to assess interleukin-17 (IL-17) and vascular endothelial growth factor (VEGF) in cancer patients receiving zoledronic acid and/or bevacizumab. The markers were also assessed in the serum.

METHODS

Twenty-five patients were included and comprised three groups: patients who received zoledronic acid (n = 9), patients who received bevacizumab (n = 9), and patients who received zoledronic acid combined with bevacizumab (n = 5). One patient received zoledronic acid and everolimus and another received zoledronic acid, bevacizumab, and temsirolimus. IL-17 and VEGF were measured by standard quantitative ELISA kits and assessed in two study points.

RESULTS

Twenty-four patients maintained good periodontal health; one had asymptomatic osteonecrosis of the jaw. First assessment: 44 samples were collected; 21 from serum and 23 from crevicular fluid. Second assessment, 6 months later: 11 samples were collected; 6 from serum and 5 from crevicular fluid. IL-17 was detected in all samples, in serum and crevicular fluid, and remained unchanged at both time points. Serum VEGF in patients with bevacizumab alone or combined with zoledronic acid was significantly lower compared with that of patients who received zoledronic acid alone. VEGF was not detected in the crevicular fluid.

CONCLUSIONS

Crevicular fluid might be an easy, non-invasive means to assess IL-17. The stable values of IL-17 in crevicular fluid and serum and the lack of VEGF in the crevicular fluid could be related to the good periodontal health of our patients. Further studies are needed to assess IL-17 and VEGF in the crevicular fluid in patients with and without periodontal disease.

Melatonin Enhances the Usefulness of Ionizing Radiation: Involving the Regulation of Different Steps of the Angiogenic Process

Radiotherapy is a part of cancer treatment. To improve its efficacy has been combined with radiosensitizers such as antiangiogenic agents. Among the mechanisms of the antitumor action of melatonin are antiangiogenic effects. Our goal was to investigate whether melatonin may modulate the sensitivity of endothelial cells (HUVECs) to ionizing radiation. Melatonin (1 mM) enhanced the inhibition induced by radiation on different steps of the angiogenic process, cell proliferation, migration, and tubular network formation. In relation with the activity and expression of enzymes implicated in estrogen synthesis, in co-cultures HUVECs/MCF-7, radiation down-regulated aromatase mRNA expression, aromatase endothelial-specific promoter I.7, sulfatase activity and expression and 17β-HSD1 activity and expression and melatonin enhanced these effects. Radiation and melatonin induced a significant decrease in VEGF, ANG-1, and ANG-2 mRNA expression. In ANG-2 and VEGF mRNA expression melatonin potentiated the inhibitory effect induced by radiation. In addition, melatonin counteracted the stimulatory effect of radiation on FGFR3, TGFα, JAG1, IGF-1, and KDR mRNA expression and reduced ANPEP expression. In relation with extracellular matrix molecules, radiation increased MMP14 mRNA expression and melatonin counteracted the stimulatory effect of radiation on MMP14 mRNA expression and increased TIMP1 expression, an angiogenesis inhibitor. Melatonin also counteracted the stimulatory effect of radiation on CXCL6, CCL2, ERK1, ERK2, and AKT1 mRNA expression and increased the inhibitory effect of radiation on NOS3 expression. In CAM assay, melatonin enhanced the reduction of the vascular area induced by radiation. Melatonin potentiated the inhibitory effect on the activation of p-AKT and p-ERK exerted by radiation. Antiangiogenic effect of melatonin could be mediated through AKT and ERK pathways, proteins involved in vascular endothelial (VE) cell growth, cell proliferation, survival, migration, and angiogenesis. In addition, radiation increased endothelial cell permeability and melatonin counteracted it by regulating the internalization of VE-cadherin. Radiation has some side effects on angiogenesis that may reduce its effectiveness against tumor growth and melatonin is able to neutralize these negative actions of radiation. Additionally, melatonin potentiated radiation-induced antiangiogenic actions on several steps of the angiogenic process and enhanced its antitumor action. Our findings point to melatonin as a useful molecule as adjuvant to radiotherapy in cancer treatment.

Tspan8 and Tspan8/CD151 knockout mice unravel the contribution of tumor and host exosomes to tumor progression

BACKGROUND

The tetraspanins Tspan8 and CD151 promote metastasis, exosomes (Exo) being suggested to be important in the crosstalk between tumor and host. The contribution of Tspan8 and CD151 to host versus tumor-derived exosome (TEX) activities being not defined, we approached the questions using 3-methylcholanthrene-induced (MCA) tumors from wt, Tspan8ko, CD151ko and Tspan8/CD151 (db)ko mice, implanted into tetraspanin-competent and deficient hosts.

METHODS

Tumor growth and dissemination, hematopoiesis and angiogenesis were surveyed in wild type (wt), Tspan8ko, CD151ko and dbko mice bearing tetraspanin-competent and -deficient MCA tumors. In vitro studies using tumor cells, bone marrow cells (BMC) and endothelial cells (EC) elaborated the mechanism of serum (s)Exo- and TEX-induced target modulation.

RESULTS

Tumors grew in autochthonous and syngeneic hosts differing in Tspan8- and/or CD151-competence. However, Tspan8ko- and/or CD151ko-tumor cell dissemination and settlement in metastatic organs was significantly reduced in the autochthonous host, and less severely in the wt-host. Impaired wt-MCA tumor dissemination in the ko-host confirmed a contribution of host- and tumor-Tspan8/-CD151 to tumor cell dissemination, delivery of sExo and TEX being severely impaired by a Tspan8ko/CD151ko. Coculturing tumor cells, BMC and EC with sExo and TEX revealed minor defects in epithelial mesenchymal transition and apoptosis resistance of ko tumors. Strongly reduced migratory and invasive capacity of Tspan8ko/CD151ko-MCA relies on distorted associations with integrins and CAM and missing Tspan8/CD151-promoted recruitment of proteases. The defects, differing between Tspan8ko- and CD151ko-MCA, were rescued by wt-TEX and, less efficiently Tspan8ko- and CD151ko-TEX. Minor defects in hematopoietic progenitor maturation were based on the missing association of hematopoietic growth factors /- receptors with CD151 and, less pronounced, Tspan8. Rescue of impaired angiogenesis in ko mice by wt-sExo and promotion of angiogenesis by TEX depended on the association of Tspan8 and CD151 with GPCR and RTK in EC and tumor cells.

CONCLUSIONS

Tspan8-/CD151-TEX play central roles in tumor progression. Tspan8-/CD151-sExo and TEX contribute by stimulating angiogenesis. Tspan8 and CD151 fulfill these tasks by associating with function-relevant proteins, the additive impact of Tspan8 and CD151 relying on differences in preferred associations. The distinct Tspan8 and CD151 contributions suggest a blockade of TEX-Tspan8 and -CD151 promising for therapeutic intervention.

Melatonin restricts the viability and angiogenesis of vascular endothelial cells by suppressing HIF-1α/ROS/VEGF

Angiogenesis is an essential process involved in various physiological, including placentation, and pathological, including cancer and endometriosis, processes. Melatonin (MLT), a well-known natural hormone secreted primarily in the pineal gland, is involved in regulating neoangiogenesis and inhibiting the development of a variety of cancer types, including lung and breast cancer. However, the specific mechanism of its anti-angiogenesis activity has not been systematically elucidated. In the present study, the effect of MLT on viability and angiogenesis of human umbilical vein endothelial cells (HUVECs), and the production of vascular endothelial growth factor (VEGF) and reactive oxygen species (ROS), under normoxia or hypoxia was analyzed using Cell Counting kit 8, tube formation, flow cytometry, ELISA and western blot assays. It was determined that the secretion of VEGF by HUVECs was significantly increased under hypoxia, while MLT selectively obstructed VEGF release as well as the production of ROS under hypoxia. Furthermore, MLT inhibited the viability of HUVECs in a dose-dependent manner and reversed the increase in cell viability and tube formation that was induced by hypoxia/VEGF/H₂O₂. Additionally, treatment with an inhibitor of hypoxia inducible factor (HIF)-1α (KC7F2) and MLT synergistically reduced the release of ROS and VEGF, and inhibited cell viability and tube formation of HUVECs. These observations demonstrate that MLT may serve dual roles in the inhibition of angiogenesis, as an antioxidant and a free radical scavenging agent. MLT suppresses the viability and angiogenesis of HUVECs through the downregulation of HIF-1α/ROS/VEGF. In summary, the present data indicate that MLT may be a potential anticancer agent in solid tumors with abundant blood vessels, particularly combined with KC7F2.

Tumor Microenvironment Targeted Nanotherapy

Recent developments in nanotechnology have brought new approaches to cancer diagnosis and therapy. While enhanced permeability and retention effect promotes nano-chemotherapeutics extravasation, the abnormal tumor vasculature, high interstitial pressure and dense stroma structure limit homogeneous intratumoral distribution of nano-chemotherapeutics and compromise their imaging and therapeutic effect. Moreover, heterogeneous distribution of nano-chemotherapeutics in non-tumor-stroma cells damages the non-tumor cells, and interferes with tumor-stroma crosstalk. This can lead not only to inhibition of tumor progression, but can also paradoxically induce acquired resistance and facilitate tumor cell proliferation and metastasis. Overall, the tumor microenvironment plays a vital role in regulating nano-chemotherapeutics distribution and their biological effects. In this review, the barriers in tumor microenvironment, its consequential effects on nano-chemotherapeutics, considerations to improve nano-chemotherapeutics delivery and combinatory strategies to overcome acquired resistance induced by tumor microenvironment have been summarized. The various strategies viz., nanotechnology based approach as well as ligand-mediated, redox-responsive, and enzyme-mediated based combinatorial nanoapproaches have been discussed in this review.

Does metronomic chemotherapy induce tumor angiogenic dormancy? A review of available preclinical and clinical data

Tumor dormancy is the ability of cancer cells to survive in a non-proliferating state. This condition can depend on three main mechanisms: cell cycle arrest (quiescence or cell dormancy), immunosurveillance (immunologic dormancy), or lack of functional blood vessels (angiogenic dormancy). In particular, under angiogenic dormancy, cancer cell proliferation is counterbalanced by apoptosis owing to poor vascularization, impeding tumor mass expansion beyond a microscopic size, with an asymptomatic and non-metastatic state. Tumor vasculogenic or non-angiogenic switch is essential to promote escape from tumor dormancy, leading to tumor mass proliferation and metastasis. In avascular lesions angiogenesis process results blocked from the equilibrium between pro- and anti-angiogenic factors, such as vascular endothelial growth factor (VEGF) and thrombospondin-1 (TSP-1), respectively. The angiogenic switch mainly depends on the disruption of this balance, in favor of pro-angiogenic factors, and on the recruitment of circulating endothelial progenitors (CEPs) that promote the formation of new blood vessels. Metronomic chemotherapy, the regular intake of doses able to sustain low but active concentrations of chemotherapeutic drugs during protracted time periods, is an encouraging therapeutic approach that has shown to upregulate anti-angiogenic factors such as TSP-1 and decline pro-angiogenic factors such as VEGF, suppressing the proangiogenic cells such as CEPs. In this perspective, metronomic chemotherapy may be one of the available therapeutic approaches capable to modulate favorably the angiogenic tumor dormancy, but further research is essential to better define this particular characteristic.

Heterogeneous effects of M-CSF isoforms on the progression of MLL-AF9 leukemia

Macrophage colony-stimulating factor (M-CSF) regulates both malignant cells and microenvironmental cells. Its splicing isoforms show functional heterogeneity. However, their roles on leukemia have not been well established. Here, the expression of total M-CSF in patients with hematopoietic malignancies was analyzed. The roles of M-CSF isoforms on the progression of acute myeloid leukemia (AML) were studied by establishing MLL-AF9-induced mouse AML models with high level membrane-bound M-CSF (mM-CSF) or soluble M-CSF (sM-CSF). Total M-CSF was highly expressed in myeloid leukemia patients. Furthermore, mM-CSF but not sM-CSF prolonged the survival of leukemia mice. While sM-CSF was more potent to promote proliferation and self-renew, mM-CSF was more potent to promote differentiation. Moreover, isoforms had different effects on leukemia-associated macrophages (LAMs) though they both increase monocytes/macrophages by growth-promoting and recruitment effects. In addition, mM-CSF promoted specific phagocytosis of leukemia cells by LAMs. RNA-seq analysis revealed that mM-CSF enhanced phagocytosis-associated genes and activated oxidative phosphorylation and metabolism pathway. These results highlight heterogeneous effects of M-CSF isoforms on AML progression and the mechanisms of mM-CSF, that is, intrinsically promoting AML cell differentiation and extrinsically enhancing infiltration of macrophages and phagocytosis by macrophages, which may provide potential clues for clinical diagnosis and therapy.

G Protein-Coupled Receptors at the Crossroad between Physiologic and Pathologic Angiogenesis: Old Paradigms and Emerging Concepts

G protein-coupled receptors (GPCRs) have been implicated in transmitting signals across the extra- and intra-cellular compartments, thus allowing environmental stimuli to elicit critical biological responses. As GPCRs can be activated by an extensive range of factors including hormones, neurotransmitters, phospholipids and other stimuli, their involvement in a plethora of physiological functions is not surprising. Aberrant GPCR signaling has been regarded as a major contributor to diverse pathologic conditions, such as inflammatory, cardiovascular and neoplastic diseases. In this regard, solid tumors have been demonstrated to activate an angiogenic program that relies on GPCR action to support cancer growth and metastatic dissemination. Therefore, the manipulation of aberrant GPCR signaling could represent a promising target in anticancer therapy. Here, we highlight the GPCR-mediated angiogenic function focusing on the molecular mechanisms and transduction effectors driving the patho-physiological vasculogenesis. Specifically, we describe evidence for the role of heptahelic receptors and associated G proteins in promoting angiogenic responses in pathologic conditions, especially tumor angiogenesis and progression. Likewise, we discuss opportunities to manipulate aberrant GPCR-mediated angiogenic signaling for therapeutic benefit using innovative GPCR-targeted and patient-tailored pharmacological strategies.

IL-3R-alpha blockade inhibits tumor endothelial cell-derived extracellular vesicle (EV)-mediated vessel formation by targeting the β-catenin pathway

The proangiogenic cytokine Interleukin-3 (IL-3) is released by inflammatory cells in breast and ovarian cancer tissue microenvironments and also acts as an autocrine factor for human breast and kidney tumor-derived endothelial cells (TECs). We have previously shown that IL-3-treated endothelial cells (ECs) release extracellular vesicles (EVs), which serve as a paracrine mechanism for neighboring ECs, by transferring active molecules. The impact of an anti-IL-3R-alpha blocking antibody on the proangiogenic effect of EVs released from TECs (anti-IL-3R-EVs) has therefore been investigated in this study. We have found that anti-IL-3R-EV treatment prevented neovessel formation and, more importantly, also induced the regression of in vivo TEC-derived neovessels. Two miRs that target the canonical wingless (Wnt)/β-catenin pathway, at different levels, were found to be differentially regulated when comparing the miR-cargo of naive TEC-derived EVs (EVs) and anti-IL-3R-EVs. miR-214-3p, which directly targets β-catenin, was found to be upregulated, whereas miR-24-3p, which targets adenomatous polyposis coli (APC) and glycogen synthase kinase-3β (GSK3β), was found to be downregulated. In fact, upon their transfer into the cell, low β-catenin content and high levels of the two members of the “β-catenin destruction complex” were detected. Moreover, c-myc downregulation was found in TECs treated with anti-IL-3R-EVs, pre-miR-214-3p-EVs and antago-miR-24-3p-EVs, which is consistent with network analyses of miR-214-3p and miR-24-3p gene targeting. Finally, in vivo studies have demonstrated the impaired growth of vessels in pre-miR-214-3p-EV- and antago-miR-24-3p-EV-treated animals. These effects became much more evident when combo treatment was applied. The results of the present study identify the canonical Wnt/β-catenin pathway as a relevant mechanism of TEC-derived EV proangiogenic action. Furthermore, we herein provide evidence that IL-3R blockade may yield some significant advantages, than miR targeting, in inhibiting the proangiogenic effects of naive TEC-derived EVs by changing TEC-EV-miR cargo.

The Potential Roles of MELF-Pattern, Microvessel Density, and VEGF Expression in Survival of Patients with Endometrioid Endometrial Carcinoma: A Morphometrical and Immunohistochemical Analysis of 100 Cases

Background

In this study, we hypothesized that microcystic, elongated, fragmented (MELF)-pattern, vascular endothelial growth factor (VEGF) expression by cancer cells and microvessel density of cancer stroma may be associated with progression of endometrioid adenocarcinoma.

Methods

The study used data from the Belarus Cancer Registry and archival histological material of 100 patients with retrospectively known good (survival) and poor (disease progression and death) outcomes. All cases were immunohistochemically stained for CD34 and VEGF. Two independent samples were compared for the characteristics of signs, and obtained results were analyzed by receiver operating characteristic analysis, Mann-Whitney U test, χ² test (Yates correction), and Mantel-Cox test. Multivariate Cox hazard analysis and Spearman correlation test were used. A p-value of less than .05 was considered statistically significant.

Results

The observed survival rate of patients with endometrioid adenocarcinoma was significantly lower (p = .002) in MELF-pattern positive patients when compared with MELF-pattern negative patients. The overall survival rate of patients whose tumors had more than 114 vessels/mm² of tissue was significantly low (p < .001). Interestingly, a similar observation was found in patients with increased vessel area, evidenced by VEGF expression in the glandular tumor component.

Conclusions

Our study suggests, for the first time, that these criteria may be used as risk factors of endometrioid adenocarcinoma progression during 5 years after radical surgical treatment. However, a large independent cohort of samples should be considered in the future to validate our findings.

c-Kit-Positive Adipose Tissue-Derived Mesenchymal Stem Cells Promote the Growth and Angiogenesis of Breast Cancer

Background

Adipose tissue-derived mesenchymal stem cells (ASCs) improve the regenerative ability and retention of fat grafts for breast reconstruction in cancer patients following mastectomy. However, ASCs have also been shown to promote breast cancer cell growth and metastasis. For the safety of ASC application, we aimed to identify specific markers for the subpopulation of ASCs that enhance the growth of breast cancer.

Methods

ASCs and bone marrow-derived vascular endothelial progenitor cells (EPCs) were isolated from Balb/c mice. c-Kit-positive (c-Kit⁺) or c-Kit-negative (c-Kit⁻) ASCs were cocultured with 4T1 breast cancer cells. Orthotropic murine models of 4T1, EPCs + 4T1, and c-Kit^+/-ASCs + 4T1/EPCs were established in Balb/c mice.

Results

In coculture, c-Kit⁺ ASCs enhanced the viability and proliferation of 4T1 cells and stimulated c-Kit expression and interleukin-3 (IL-3) release. In mouse models, c-Kit⁺ASCs + 4T1/EPCs coinjection increased the tumor volume and vessel formation. Moreover, IL-3, stromal cell-derived factor-1, and vascular endothelial growth factor A in the c-Kit⁺ASCs + 4T1/EPCs coinjection group were higher than those in the 4T1, EPCs + 4T1, and c-Kit⁻ASCs + 4T1/EPCs groups.

Conclusions

c-Kit⁺ ASCs may promote breast cancer growth and angiogenesis by a synergistic effect of c-Kit and IL-3. Our findings suggest that c-Kit⁺ subpopulations of ASCs should be eliminated in fat grafts for breast reconstruction of cancer patients following mastectomy.

Ramucirumab in the treatment of non-small cell lung cancer

INTRODUCTION

Therapeutic options for treating Non-Small Cell Lung Cancer (NSCLC) have recently increased. Ramucirumab (Cyramza), an anti-angionenic agent was approved in 2014 for treatment of several malignancies, including second-line treatment of patients with NSCLC with disease progression on or after platinum-based chemotherapy. Areas covered: We performed a comprehensive search of the literature focused on clinical trials with use of ramucirumab, targeting its evolution in the treatment of NSCLC. This review summarizes the results regarding its safety and efficacy. Expert opinion: Angiogenesis has been widely recognized as a quintessential feature in cancer, intrinsically mediating tumor survival and progression. Ramucirumab, an anti-VEGFR2 agent, combined with docetaxel, was FDA-approved for NSCLC patients. Results from a phase III trial have demonstrated the usefulness of this combination, with benefits in progression free survival and overall survival for NSCLC patients. A greater magnitude of benefit is seen in patients with aggressive tumor behavior. Treatment with ramucirumab is generally tolerable, however, there is potential for severe toxicity. Adverse events reported with this combination include neutropenia, febrile neutropenia and hypertension. Also, there is the intrinsic risk of bleeding resulting from the mechanism of action. As such, adverse events should be identified timely, so drug-related complications can be prevented.

Differential effects of recombinant human endostatin treatment on differentiated and undifferentiated blood vessels in Lewis lung cancer

In the present study, we evaluated the effects of recombinant human (rh-)endostatin treatment on differentiated and undifferentiated tumor vasculature in Lewis lung cancer for the first time. Lewis lung carcinoma models were established. The animals were treated daily with varying doses of rh-endostatin or physiological saline for 14 days. Intravital microscopy was performed following treatment. The expression of CD31 and CD34 was determined by immunohistochemical staining, and microvessel density (MVD) was determined. Rh-endostatin treatment significantly decreased the tumor volume compared with the control group. Rh-endostatin treatment normalized the architecture of the vascular network. CD31⁺ cells decreased following rh-endostatin treatment, whereas CD34⁺ cells were unaffected by the treatment. Accordingly, the MVD value of CD31⁺ cells in rh-endostatin treatment groups significantly decreased (P<0.01), and the MVD value of CD34⁺ cells in the rh-endostatin treatment groups did not decrease. Undifferentiated tumor blood vessels were significantly inhibited by rh-endostatin treatment. In conclusion, the normalization of the tumor vasculature by endostatin may be related to the differential effects of endostatin on differentiated and undifferentiated blood vessels.

Evaluation of Curcumin Capped Copper Nanoparticles as Possible Inhibitors of Human Breast Cancer Cells and Angiogenesis: a Comparative Study with Native Curcumin

Synthesis of metal nanoparticles for improving therapeutic index and drug delivery is coming up as an attractive strategy in the mainstream of cancer therapeutic research. In the present study, curcumin-capped copper nanoparticles (CU-NPs) were evaluated as possible inhibitors of in vivo angiogenesis, pro-angiogenic cytokines involved in promoting tumor angiogenesis along with inhibition of cell proliferation and migration of breast cancer cell line MDA-MB-231. The antiangiogenic potential was assessed using in vivo chorioallantoic membrane (CAM) model. 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT)-based cytotoxicity assay was used to assess the effect of CU-NPs against proliferation of breast cancer cell line. The wound healing migration assay was used to evaluate the effects of CU-NPs on the migration ability of breast cancer cell line. Native curcumin (CU) was used as a reference compound for comparison purpose. The result of the present investigation indicates that CU-NPs could not demonstrate impressive antiangiogenic or anticancer activities significantly as compared to native CU. The possible mechanisms of experimental outcomes are discussed in the light of the methods of nanoparticle synthesis in concert with the current state of the art literature.