Identification of ATAD3A as a key regulator in non-small cell lung cancer by promoting STAT3-induced cell proliferation and tumor angiogenesis

Malignant proliferation and abundant angiogenesis are major causes of lung adenocarcinoma (LUAD) with high morbidity and mortality. Therefore, the exploration of the key regulatory mechanisms of malignant proliferation and angiogenesis in LUAD provides an opportunity for the development of targeted precision therapy. In this study, we found that the high expression of ATPase family AAA domain-containing protein 3A (ATAD3A) in LUAD was positively associated with the poor survival of patients, while its high expression was positively associated with the angiogenesis of LUAD. Further knockdown of ATAD3A in LUAD significantly inhibited cell proliferation and suppressed expression of vascular endothelial growth factor A, FGF-2, ANG-1, and TGF-β. The opposite effect was observed with ATAD3A overexpression. Furthermore, ATAD3A knockdown significantly inhibited tumor growth and angiogenesis in an in vivo subcutaneous xenograft tumor model. Mechanistic studies suggest that ATAD3A may promote signal transducer and activator of transcription 3 activation, a key signal regulating lung cancer cell proliferation and transcriptional secretion of proangiogenic factors. Therefore, targeted inhibition of ATAD3A may be an effective strategy for LUAD therapy, and ATAD3A may be a potential biomarker for predicting malignant progression.

Roles of endothelial cell specific molecule‑1 in tumor angiogenesis (Review)

Angiogenesis plays a crucial role in tumor growth and metastasis, and is heavily influenced by the tumor microenvironment (TME). Endothelial cell dysfunction is a key factor in tumor angiogenesis and is characterized by the aberrant expression of pro-angiogenic factors. Endothelial cell specific molecule-1 (ESM1), also known as endocan, is a marker of endothelial cell dysfunction. Although ESM1 is primarily expressed in normal endothelial cells, dysregulated ESM1 expression has been observed in human tumors and animal tumor models, and implicated in tumor growth, metastasis and angiogenesis. The precise role of ESM1 in tumor angiogenesis and its potential regulatory mechanisms are not yet conclusively defined. However, the aim of the present review was to explore the involvement of ESM1 in the process of tumor angiogenesis in the TME and the characteristics of neovascularization. In addition, the present review discusses the interaction between ESM1 and angiogenic factors, as well as the mechanisms through which ESM1 contributes to tumor angiogenesis. Furthermore, the reciprocal regulation between ESM1 and the TME is explored. Finally, the potential of targeting ESM1 as a therapeutic strategy for tumor angiogenesis is presented.

Super-Resolution Ultrasound Imaging for Monitoring the Therapeutic Efficacy of a Vascular Disrupting Agent in an Animal Model of Breast Cancer

OBJECTIVE

Evaluate the use of super-resolution ultrasound (SRUS) imaging for the early detection of tumor response to treatment using a vascular-disrupting agent (VDA).

METHODS

A population of 28 female nude athymic mice (Charles River Laboratories) were implanted with human breast cancer cells (MDA-MB-231, ATCC) in the mammary fat pad and allowed to grow. Ultrasound imaging was performed using a Vevo 3100 scanner (FUJIFILM VisualSonics Inc) equipped with the MX250 linear array transducer immediately before and after receiving bolus injections of a microbubble (MB) contrast agent (Definity, Lantheus Medical Imaging) via the tail vein. Following baseline ultrasound imaging, VDA drug (combretastatin A4 phosphate, CA4P, Sigma Aldrich) or control saline was injected via the placed catheter. After 4 or 24 hours, repeat ultrasound imaging along the same tumor cross-section occurred. Direct intratumoral pressure measurements were obtained using a calibrated sensor. All raw ultrasound data were saved for offline processing and SRUS image reconstruction using custom MATLAB software (MathWorks Inc). From a region encompassing the tumor space and the entire postprocessed ultrasound image sequence, time MB count (TMC) curves were generated in addition to traditional SRUS maps reflecting MB enumeration at each pixel location. Peak enhancement (PE) and wash-in rate (WIR) were extracted from these TMC curves. At termination, intratumoral microvessel density (MVD) was quantified using tomato lectin labeling of patent blood vessels.

RESULTS

SRUS images exhibited a clear difference between control and treated tumors. While there was no difference in any group parameters at baseline (0 hour, P > .09), both SRUS-derived PE and WIR measurements in tumors treated with VDA exhibited significant decreases by 4 (P = .03 and P = .05, respectively) and 24 hours (P = .02 and P = .01, respectively), but not in control group tumors (P > .22). Similarly, SRUS derived microvascular maps were not different at baseline (P = .81), but measures of vessel density were lower in treated tumors at both 4 and 24 hours (P < .04). An inverse relationship between intratumoral pressure and both PE and WIR parameters were found in control tumors (R2  > .09, P < .03).

CONCLUSION

SRUS imaging is a new modality for assessing tumor response to treatment using a VDA.

Glucagon Enhances Chemotherapy Efficacy By Inhibition of Tumor Vessels in Colorectal Cancer

Chemotherapy is widely used to treat colorectal cancer (CRC). Despite its substantial benefits, the development of drug resistance and adverse effects remain challenging. This study aimed to elucidate a novel role of glucagon in anti-cancer therapy. In a series of in vitro experiments, glucagon inhibited cell migration and tube formation in both endothelial and tumor cells. In vivo studies demonstrated decreased tumor blood vessels and fewer pseudo-vessels in mice treated with glucagon. The combination of glucagon and chemotherapy exhibited enhanced tumor inhibition. Mechanistic studies demonstrated that glucagon increased the permeability of blood vessels, leading to a pronounced disruption of vessel morphology. Signaling pathway analysis identified a VEGF/VEGFR-dependent mechanism whereby glucagon attenuated angiogenesis through its receptor. Clinical data analysis revealed a positive correlation between elevated glucagon expression and chemotherapy response. This is the first study to reveal a role for glucagon in inhibiting angiogenesis and vascular mimicry. Additionally, the delivery of glucagon-encapsulated PEGylated liposomes to tumor-bearing mice amplified the inhibition of angiogenesis and vascular mimicry, consequently reinforcing chemotherapy efficacy. Collectively, the findings demonstrate the role of glucagon in inhibiting tumor vessel network and suggest the potential utility of glucagon as a promising predictive marker for patients with CRC receiving chemotherapy.

Suppression of Sleeping Beauty-induced Gliomagenicity in Ts1Cje Mice, a Model of Down Syndrome

BACKGROUND/AIM

Individuals with Down syndrome (DS), attributed to triplication of human chromosome 21 (Hsa21), exhibit a reduced incidence of solid tumors. However, the prevalence of glioblastoma among individuals with DS remains a contentious issue in epidemiological studies. Therefore, this study examined the gliomagenicity in Ts1Cje mice, a murine model of DS.

MATERIALS AND METHODS

We employed the Sleeping Beauty transposon system for the integration of human oncogenes into cells of the subventricular zone of neonatal mice.

RESULTS

Notably, Sleeping Beauty-mediated de novo murine gliomagenesis was significantly suppressed in Ts1Cje mice compared to wild-type mice. In glioblastomas of Ts1je mice, we observed an augmented presence of M1-polarized tumor-associated macrophages and microglia, known for their anti-tumor efficacy in the early stage of tumor development.

CONCLUSION

Our findings in a mouse model of DS offer novel perspectives on the diminished gliomagenicity observed in individuals with DS.

Regulation of Angiogenesis by Non-Coding RNAs in Cancer

Non-coding RNAs, including microRNAs, long non-coding RNAs, and circular RNAs, have been identified as crucial regulators of various biological processes through epigenetic regulation, transcriptional regulation, and post-transcriptional regulation. Growing evidence suggests that dysregulation and activation of non-coding RNAs are closely associated with tumor angiogenesis, a process essential for tumor growth and metastasis and a major contributor to cancer-related mortality. Therefore, understanding the molecular mechanisms underlying tumor angiogenesis is of utmost importance. Numerous studies have documented the involvement of different types of non-coding RNAs in the regulation of angiogenesis. This review provides an overview of how non-coding RNAs regulate tumor angiogenesis. Additionally, we discuss emerging strategies that exploit non-coding RNAs for anti-angiogenic therapy in cancer treatment. Ultimately, this review underscores the crucial role played by non-coding RNAs in tumor angiogenesis and highlights their potential as therapeutic targets for anti-angiogenic interventions against cancer.

Tumor vaccines: Toward multidimensional anti-tumor therapies

For decades, immunotherapies have offered hope for patients with advanced cancer. However, they show distinct benefits and limited clinical effects. Tumor vaccines have the potential to prime tumor-antigen-specific T cells and induce broad subsets of immune responses, ultimately eradicating tumor cells. Here, we classify tumor vaccines by their anti-tumor mechanisms, which include boosting the immune system, overcoming tumor immunosuppression, and modulating tumor angiogenesis. We focus on multidimensional tumor vaccine strategies using combinations of two or three of the above mechanisms, as these are superior to single-dimensional treatments. This review offers a perspective on tumor vaccine strategies and the future role of vaccine therapies in cancer treatment.

Cabozantinib in neuroendocrine tumors: tackling drug activity and resistance mechanisms

Neuroendocrine tumors (NETs) are highly vascularized malignancies in which angiogenesis may entail cell proliferation and survival. Among the emerging compounds with antivascular properties, cabozantinib (CAB) appeared promising. We analyzed the antitumor activity of CAB against NETs utilizing in vitro and in vivo models. For cell cultures, we used BON-1, NCI-H727 and NCI-H720 cell lines. Cell viability was assessed by manual count coupled with quantification of cell death, performed through fluorescence-activated cell sorting analysis as propidium iodide exclusion assay. In addition, we investigated the modulation of the antiapoptotic myeloid cell leukemia 1 protein under CAB exposure, as a putative adaptive pro-survival mechanism, and compared the responses with sunitinib. The activity of CAB was also tested in mouse and zebrafish xenograft tumor models. Cabozantinib showed a dose-dependent and time-dependent effect on cell viability and proliferation in human NET cultures, besides a halting of cell cycle progression for endoduplication, never reported for other tyrosine kinase inhibitors. In a transplantable zebrafish model, CAB drastically inhibited NET-induced angiogenesis and migration of implanted cells through the embryo body. CAB showed encouraging activity in NETs, both in vitro and in vivo models. On this basis, we envisage future research to further investigate along these promising lines.

[Corrigendum] Fully human VEGFR2 monoclonal antibody BC001 attenuates tumor angiogenesis and inhibits tumor growth

Subsequently to the publication of the above paper, an interested reader drew to the authors' attention that, for the scratch wound assay experiments shown in Fig. 1 on p. 2413, the panels showing the '0 h' experiments for the respective incubations with VEGF or BC001 were apparently identical. The authors were able to re‑examine their original data files, and realized that this figure had been inadverently assembled incorrectly. The revised version of Fig. 1, containing the correct data for the '0 h / BC001' panel, is shown below. Note that the revisions made to this figure do not affect the overall conclusions reported in the paper. The authors are grateful to the Editor of International Journal of Oncology for allowing them the opportunity to publish this Corrigendum, and apologize to the readership for any inconvenience caused. [International Journal of Oncology 45: 2411‑2420, 2014; DOI: 10.3892/ijo.2014.2690].

Radiosynthesis of Stable 198Au-Nanoparticles by Neutron Activation of αvβ3-Specific AuNPs for Therapy of Tumor Angiogenesis

This paper reports on the development of stable tumor-specific gold nanoparticles (AuNPs) activated by neutron irradiation as a therapeutic option for the treatment of cancer with high tumor angiogenesis. The AuNPs were designed with different mono- or dithiol-ligands and decorated with different amounts of Arg-Gly-Asp (RGD) peptides as a tumor-targeting vector for αvβ3 integrin, which is overexpressed in tissues with high tumor angiogenesis. The AuNPs were evaluated for avidity in vitro and showed favorable properties with respect to tumor cell accumulation. Furthermore, the therapeutic properties of the [198Au]AuNPs were evaluated in vitro on U87MG cells in terms of cell survival, suggesting that these [198Au]AuNPs are a useful basis for future therapeutic concepts.

The Antitumor Impact of Combining Hepatic Artery Ligation With Copper Chelators for Liver Cancer

Background

Hepatocellular carcinoma (HCC) is one of the main cancer-related mortality worldwide. Thus, there is a constant search for improvement in treatment strategies to enhance the prognosis of this malignancy. The study aims to investigate the combined antitumor activity of ammonium tetrathiomolybdate (TM, copper chelator) combined with hepatic artery ligation (HAL) for liver cancer.

Methods

A total of 40 Sprague-Dawley (SD) rats bearing hepatic tumors were randomly divided into four groups: the control group without any treatment (control), HAL only (HAL), given TM by gavage (TM), and given TM combined with HAL (HAL + TM). The concentrations of serum copper were measured at the predetermined time points. Tumor growth rate, overall survival (OS), expression of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), and microvessel density (MVD), as determined by immunohistochemical examination, were compared.

Results

HAL treatment transiently could elevate alanine transaminase (ALT) and aspartate transaminase (AST) but resumed to baseline within 1 week. Serum copper was significantly increased in tumor-bearing animals over time. The values of serum copper in the three treatment groups were significantly lower than those in the control group at different time points, with the lowest values observed in the TM group (P < .05). The average tumor size was 30.33 ± 2.58, 20.83 ± 2.93, 16.80 ± 3.84, and 10.88 ± 1.08 mm in the control, HAL, TM, and HAL + TM groups, respectively (HAL + TM vs other groups, all P < .05). In addition, the expression levels of HIF-1α, VEGF, and MVD were significantly lower in the HAL + TM group than those in the other groups (P < .05). The OS of rats in the combined groups was significantly prolonged combined to the other groups (P < .05), with survival time of 19.1 ± 0.64, 25.4 ± 1.24, 25.3 ± 1.78, and 29.9 ± 2.22 days in the control, HAL, TM, and HAL + TM groups, respectively.

Conclusion

These findings suggest that combined treatment with TM and HAL holds great potential for liver cancer treatment by reducing tumor hypoxia and angiogenesis. The observed results indicate that these combinations may offer a novel target and strategy for interventional therapy of liver cancer.

SEMA3B-AS1 suppresses colorectal carcinoma progression by inhibiting Semaphorin 3B-dependent VEGF signaling pathway activation

Mounting evidence has demonstrated the considerable regulatory effects of long noncoding RNAs (lncRNAs) in the tumorigenesis and progression of various carcinomas. LncRNA Semaphorin 3B (SEMA3B) antisense RNA 1 (SEMA3B-AS1) has been found to be dysregulated in a few carcinomas recently. However, its potential function and mechanism in colorectal carcinoma (CRC) have not yet been examined. Here we show that SEMA3B-AS1 acts as a crucial regulator of CRC progression. We found that SEMA3B-AS1 expression was downregulated in CRC cell lines and tissues. Downregulation of SEMA3B-AS1 was significantly associated with poor survival in CRC patients. Overexpression of SEMA3B-AS1 reduced the cell growth and metastasis of CRC in vivo and in vitro. In addition, SEMA3B-AS1 promoted the expression of its sense-cognate gene SEMA3B, a member of the Semaphorin family (SEMAs), by recruiting EP300 to induce H3K9 acetylation at the SEMA3B promoter. Furthermore, we proved that SEMA3B-AS1 suppressed CRC angiogenesis by affecting the vascular endothelial growth factor signaling pathway activation which was regulated by the SEMA3B-NRP1 axis. Our work unravels a novel mechanism of SEMA3B-AS1 in the inhibition of CRC malignant progression and highlights its probability as a new promising diagnostic marker and therapeutic target for CRC interventions.

Systemic Delivery of a STING Agonist-Loaded Positively Charged Liposome Selectively Targets Tumor Immune Microenvironment and Suppresses Tumor Angiogenesis

Although stimulator of interferon genes (STING) agonists has shown great promise in preclinical studies, the clinical development of STING agonist therapy is challenged by its limited systemic delivery. Here, positively charged fusogenic liposomes loaded with a STING agonist (PoSTING) are designed for systemic delivery and to preferentially target the tumor microenvironment. When PoSTING is administered intravenously, it selectively targets not only tumor cells but also immune and tumor endothelial cells (ECs). In particular, delivery of STING agonists to tumor ECs normalizes abnormal tumor vasculatures, induces intratumoral STING activation, and elicits robust anti-tumor T cell immunity within the tumor microenvironment. Therefore, PoSTING can be used as a systemic delivery platform to overcome the limitations of using STING agonists in clinical trials.

The circadian protein BMAL1 supports endothelial cell cycle during angiogenesis

AIMS

The circadian clock is an internal biological timer that co-ordinates physiology and gene expression with the 24-h solar day. Circadian clock perturbations have been associated to vascular dysfunctions in mammals, and a function of the circadian clock in angiogenesis has been suggested. However, the functional role of the circadian clock in endothelial cells (ECs) and in the regulation of angiogenesis is widely unexplored.

METHODS AND RESULTS

Here, we used both in vivo and in vitro approaches to demonstrate that ECs possess an endogenous molecular clock and show robust circadian oscillations of core clock genes. By impairing the EC-specific function of the circadian clock transcriptional activator basic helix-loop-helix ARNT like 1 (BMAL1) in vivo, we detect angiogenesis defects in mouse neonatal vascular tissues, as well as in adult tumour angiogenic settings. We then investigate the function of circadian clock machinery in cultured EC and show evidence that BMAL and circadian locomotor output cycles protein kaput knock-down impair EC cell cycle progression. By using an RNA- and chromatin immunoprecipitation sequencing genome-wide approaches, we identified that BMAL1 binds the promoters of CCNA1 and CDK1 genes and controls their expression in ECs.

CONCLUSION(S)

Our findings show that EC display a robust circadian clock and that BMAL1 regulates EC physiology in both developmental and pathological contexts. Genetic alteration of BMAL1 can affect angiogenesis in vivo and in vitro settings.

Bulk RNA-Seq Combined with Single-Cell Transcriptome Sequencing Reveals the Possible Mechanisms by Which HDGFL3 Involves in Prostate Cancer Growth and Metastasis

BACKGROUND

Based on publicly available transcriptome and single-cell sequencing data, the current study aimed to explore the molecular mechanisms underlying the involvement of hepatocellular carcinoma-derived growth factor-like 3 (HDGFL3) in prostate cancer (PCA) growth and metastasis.

METHODS

The Gene Expression Omnibus database was used to download the single cell transcriptome of PCA (GSE193337). Single-cell RNA sequencing (scRNA-seq) data were examined to identify which genes are essential for endothelial cell function. The Cancer Genome Atlas Prostate Adenocarcinoma database provided the RNA sequencing data, and univariate COX regression analysis was introduced to identify the genes that were associated with the prognosis of patients with PCA. Human PCA cell lines PC-3 and DU145 were used in in vitro cellular studies to test the effect of silencing HDGFL3. The results were validated using Transwell® assay, scratch assay, and cell counting kit-8 assay. To support the role of HDGFL3 in PCA, an in vivo animal model of PCA transplantation tumor in nude mice was established. Quantitative reverse transcription polymerase chain reaction was introduced to measure HDGFL3 messenger ribonucleic acid (mRNA) expression levels in tumor tissues from nude mice, and Hematoxylin and Eosin staining was used to identify lung metastasis. Immunohistochemical staining was employed to identify the expression levels of HDGFL3 and hematopoietic progenitor cell antigen CD34+.

RESULTS

It was discovered through analysis of the scRNA-seq dataset that HDGFL3, a gene specific to endothelial cells, is linked to a poor prognosis in men with PCA. In addition, HDGFL3 and the expression of genes linked to angiogenesis have a substantial association. Studies on cells in vitro revealed that silencing HDGFL3 prevented PC-3 and DU145 cells from proliferation, migrating and invading. Silencing HDGFL3 decreased the weight of prostate tumors, the number of lung metastases, and the area occupied by CD34+ vascular endothelial cells, according to in vivo investigations.

CONCLUSIONS

This study identified HDGFL3 as a key gene in endothelial cells that may stimulate tumor angiogenesis to increase the growth and spread of PCA. These results imply that HDGFL3 may represent a possible target for antiangiogenic therapy in the management of PCA.

Vascular endothelial profilin-1 drives a protumorigenic tumor microenvironment and tumor progression in renal cancer

Overexpression of actin-binding protein profilin-1 (Pfn1) correlates with advanced disease features and adverse clinical outcome of patients with clear cell renal carcinoma, the most prevalent form of renal cancer. We previously reported that Pfn1 is predominantly overexpressed in tumor-associated vascular endothelial cells in human clear cell renal carcinoma. In this study, we combined in vivo strategies involving endothelial cell-specific depletion and overexpression of Pfn1 to demonstrate a role of vascular endothelial Pfn1 in promoting tumorigenicity and enabling progressive growth and metastasis of renal carcinoma cells in a syngeneic orthotopic mouse model of kidney cancer. We established an important role of endothelial Pfn1 in tumor angiogenesis and further identified endothelial Pfn1-dependent regulation of several pro- (VEGF, SERPINE1, CCL2) and anti-angiogenic factors (platelet factor 4) in vivo. Endothelial Pfn1 overexpression increases tumor infiltration by macrophages and concomitantly diminishes tumor infiltration by T cells including CD8+ T cells in vivo, correlating with the pattern of endothelial Pfn1-dependent changes in tumor abundance of several prominent immunomodulatory cytokines. These data were also corroborated by multiplexed quantitative immunohistochemistry and immune deconvolution analyses of RNA-seq data of clinical samples. Guided by Upstream Regulator Analysis of tumor transcriptome data, we further established endothelial Pfn1-induced Hif1α elevation and suppression of STAT1 activation. In conclusion, this study demonstrates for the first time a direct causal relationship between vascular endothelial Pfn1 dysregulation, immunosuppressive tumor microenvironment, and disease progression with mechanistic insights in kidney cancer. Our study also provides a conceptual basis for targeting Pfn1 for therapeutic benefit in kidney cancer.

Usefulness of Contrast-Enhanced Endoscopic Ultrasound (CH-EUS) to Guide the Treatment Choice in Superficial Rectal Lesions: A Case Series

INTRODUCTION

Large rectal lesions can conceal submucosal invasion and cancer nodules. Despite the increasing diffusion of high-definition endoscopes and the importance of an accurate morphological evaluation, a complete assessment in this setting can be challenging. Endoscopic ultrasound (EUS) plays an established role in the locoregional staging of rectal cancer, although this technique has a tendency toward the over-estimation of the loco-regional (T) staging. However, there are still few data on contrast-enhanced endoscopic ultrasound (CH-EUS), especially if this ancillary technique may increase the accuracy for predicting invasive nodules among large rectal lesions.

MATERIAL AND METHODS

Consecutive large (≥20 mm) superficial rectal lesions with high-definition endoscopy, characterized by focal areas suggestive for invasive cancer/2B type according to JNET classification, were considered for additional standardized evaluation via CH-EUS with Sonovue ©.

RESULTS

From 2020 to 2023, we evaluated 12 consecutive superficial rectal lesions with sizes ranging from 20 to 180 mm. This evaluation provided additional elements to support the therapeutic decision made. Lesions were treated with surgical (3/12) or endoscopic treatment (9/12) according to their morphology and CH-EUS evaluation.

CONCLUSION

Contrast-enhanced endoscopic ultrasound can provide an additional evaluation for large and difficult-to-classify rectal lesions. In our experience, CH-EUS staging corresponded to the final pathological stages in 9/12 (75%) lesions, improving the distinction between T1 and T2 lesions. Larger prospective studies and randomized trials should be conducted to support and standardize this approach.

PBRM1 and KDM5C cooperate to define high-angiogenesis tumors and increased antiangiogenic response in renal cancer

Vascular endothelial growth factor receptor tyrosine kinase inhibitors (VEGFR-TKIs) are key antiangiogenic drugs for renal cancer treatment. While Von Hippel-Lindau dysfunction constitutes the base for VEGFR-TKIs sensitivity, the role for individual and concurrent mutations in the genes encoding for the chromatin remodelers Polybromo-1 (PBRM1) and Lysine Demethylase 5C (KDM5C) is poorly understood. Here, we analyzed the tumor mutational and expression profiles of 155 unselected clear cell RCC (ccRCC) cases treated with first-line VEGFR-TKIs and the ccRCC cases of IMmotion151 trial were used for validation. We found that concurrent PBRM1 and KDM5C (PBRM1&KDM5C) mutations occurred in 4-9% of cases and were enriched in Memorial Sloan Kettering Cancer Center favorable-risk patients. In our cohort, tumors only mutated in PBRM1 or concurrently mutated in PBRM1 and KDM5C had increased angiogenesis (P=0.0068 and 0.039; respectively), and tumors only mutated in KDM5C showed a similar trend. Best response to VEGFR-TKIs corresponded to PBRM1&KDM5C mutated cases, followed by those mutated only in KDM5C or only in PBRM1 (P=0.050, 0.040 and 0.027 versus non-mutated cases, respectively), with a trend for longer progression free survival (PFS) in the group with only PBRM1 mutated (HR=0.64; P=0.059). Validation in the IMmotion151 trial revealed a similar correlation with increased angiogenesis and the PFS of patients in the VEGFR-TKI-arm was the longest in PBRM1&KDM5C mutated cases, intermediate for only PBRM1 or only KDM5C mutated patients and the shortest in non-mutated cases (P=0.009 and 0.025, for PBRM1&KDM5C and PBRM1 versus non-mutated cases). In conclusion, somatic PBRM1 and KDM5C mutations are common in patients with metastatic ccRCC and likely cooperate increasing tumor angiogenesis and VEGFR-TKI-based antiangiogenic therapy benefit.

ARL13B promotes angiogenesis and glioma growth by activating VEGFA-VEGFR2 signaling

BACKGROUND

Tumor angiogenesis is essential for solid tumor progression, invasion and metastasis. The aim of this study was to identify potential signaling pathways involved in tumor angiogenesis.

METHODS

Genetically engineered mouse models were used to investigate the effects of endothelial ARL13B(ADP-ribosylation factor-like GTPase 13B) over-expression and deficiency on retinal and cerebral vasculature. An intracranially transplanted glioma model and a subcutaneously implanted melanoma model were employed to examine the effects of ARL13B on tumor growth and angiogenesis. Immunohistochemistry was used to measure ARL13B in glioma tissues, and scRNA-seq was used to analyze glioma and endothelial ARL13B expression. GST-fusion protein-protein interaction and co-immunoprecipitation assays were used to determine the ARL13B-VEGFR2 interaction. Immunobloting, qPCR, dual-luciferase reporter assay and functional experiments were performed to evaluate the effects of ARL13B on VEGFR2 activation.

RESULTS

Endothelial ARL13B regulated vascular development of both the retina and brain in mice. Also, ARL13B in endothelial cells regulated the growth of intracranially transplanted glioma cells and subcutaneously implanted melanoma cells by controlling tumor angiogenesis. Interestingly, this effect was attributed to ARL13B interaction with VEGFR2, through which ARL13B regulated the membrane and ciliary localization of VEGFR2 and consequently activated its downstream signaling in endothelial cells. Consistent with its oncogenic role, ARL13B was highly expressed in human gliomas, which was well correlated with the poor prognosis of glioma patients. Remarkably, ARL13B, transcriptionally regulated by ZEB1, enhanced the expression of VEGFA by activating Hedgehog signaling in glioma cells.

CONCLUSIONS

ARL13B promotes angiogenesis and tumor growth by activating VEGFA-VEGFR2 signaling. Thus, targeting ARL13B might serve as a potential approach for developing an anti-glioma or anti-melanoma therapy.

Cooperation between Prostaglandin E2 and Epidermal Growth Factor Receptor in Cancer Progression: A Dual Target for Cancer Therapy

It is recognized that prostaglandin E2 (PGE2) is one key lipid mediator involved in chronic inflammation, and it is directly implicated in tumor development by regulating cancer cell growth and migration, apoptosis, epithelial-mesenchymal transition, angiogenesis, and immune escape. In addition, the expression of the enzymes involved in PGE2 synthesis, cyclooxygenase 2 (COX-2) and microsomal prostaglandin E synthase 1 (mPGES1), positively correlates with tumor progression and aggressiveness, clearly indicating the crucial role of the entire pathway in cancer. Moreover, several lines of evidence suggest that the COX2/mPGES1/PGE2 inflammatory axis is involved in the modulation of epidermal growth factor receptor (EGFR) signaling to reinforce the oncogenic drive of EGFR activation. Similarly, EGFR activation promotes the induction of COX2/mPGES1 expression and PGE2 production. In this review, we describe the interplay between COX2/mPGES1/PGE2 and EGFR in cancer, and new therapeutic strategies that target this signaling pathway, to outline the importance of the modulation of the inflammatory process in cancer fighting.

Roles of TGF-β signals in tumor microenvironment via regulation of the formation and plasticity of vascular system

Tumor cells evolve in tumor microenvironment composed of multiple cell types. Among these, endothelial cells (ECs) are the major players in tumor angiogenesis, which is a driver of tumor progression and metastasis. Increasing evidence suggests that ECs also contribute to tumor progression and metastasis as they modify their phenotypes to differentiate into mesenchymal cells through a process known as endothelial-mesenchymal transition (EndoMT). This plasticity of ECs is mediated by various cytokines, including transforming growth factor-β (TGF-β), and modulated by other stimuli depending on the cellular contexts. Recent lines of evidence have shown that EndoMT is involved in various steps of tumor progression, including tumor angiogenesis, intravasation and extravasation of cancer cells, formation of cancer-associated fibroblasts, and cancer therapy resistance. In this review, we summarize current updates on EndoMT, highlight the roles of EndoMT in tumor progression and metastasis, and underline targeting EndoMT as a potential therapeutic strategy.

Tumor Vasculature as an Emerging Pharmacological Target to Promote Anti-Tumor Immunity

Tumor vasculature abnormality creates a microenvironment that is not suitable for anti-tumor immune response and thereby induces resistance to immunotherapy. Remodeling of dysfunctional tumor blood vessels by anti-angiogenic approaches, known as vascular normalization, reshapes the tumor microenvironment toward an immune-favorable one and improves the effectiveness of immunotherapy. The tumor vasculature serves as a potential pharmacological target with the capacity of promoting an anti-tumor immune response. In this review, the molecular mechanisms involved in tumor vascular microenvironment-modulated immune reactions are summarized. In addition, the evidence of pre-clinical and clinical studies for the combined targeting of pro-angiogenic signaling and immune checkpoint molecules with therapeutic potential are highlighted. The heterogeneity of endothelial cells in tumors that regulate tissue-specific immune responses is also discussed. The crosstalk between tumor endothelial cells and immune cells in individual tissues is postulated to have a unique molecular signature and may be considered as a potential target for the development of new immunotherapeutic approaches.

Optical imaging technology realizes early tumor diagnosis by detecting angiogenesis

The occurrence and development of blood vessels play a key role in different stages of tumor growth, while current imaging techniques are difficult to detect early tumor angiogenesis because of their low sensitivity. Therefore, this article introduces high-sensitivity optical imaging technology to achieve early tumor diagnosis by detecting tumor angiogenesis. Liver and pancreatic tumor models in nude mice were respectively established to represent tumors with a rich or poor blood supply. The two optical imaging methods, in vivo confocal fluorescence imaging and photoacoustic imaging, were used to detect tumor angiogenesis at different stages. Finally, the changes in blood vessels were verified by immunostaining. Both autoluminescence imaging and pathological staining confirmed that these two tumor models were successfully established. In vivo confocal fluorescence imaging found that the early tumor blood vessel structure had obvious characteristics: disorder, tortuous deformation, thin diameter, which were significantly different from the normal tissues. Photoacoustic imaging could effectively identify blood vessels inside early tumors, which were small and disordered and might be used as one of the predictors of early tumor development. CD31 immunostaining was used to evaluate the vascular status of tumors at different stages and under different blood supply conditions. The vascular structures observed under the microscope in the two tumor models were consistent with the results observed by optical imaging methods. The optical imaging methods could monitor the characteristics of angiogenesis in the rich or poor blood supply tumors, especially the early diagnosis of tumors.

Conserved angio-immune subtypes of the tumor microenvironment predict response to immune checkpoint blockade therapy

Immune checkpoint blockade (ICB) therapy has revolutionized cancer treatment. However, only a fraction of patients respond to ICB therapy. Accurate prediction of patients to likely respond to ICB would maximize the efficacy of ICB therapy. The tumor microenvironment (TME) dictates tumor progression and therapy outcome. Here, we classify the TME by analyzing the transcriptome from 11,069 cancer patients based on angiogenesis and T cell activity. We find three distinct angio-immune TME subtypes conserved across 30 non-hematological cancers. There is a clear inverse relationship between angiogenesis and anti-tumor immunity in TME. Remarkably, patients displaying TME with low angiogenesis with strong anti-tumor immunity show the most significant responses to ICB therapy in four cancer types. Re-evaluation of the renal cell carcinoma clinical trials provides compelling evidence that the baseline angio-immune state is robustly predictive of ICB responses. This study offers a rationale for incorporating baseline angio-immune scores for future ICB treatment strategies.

Bovine Lactoferrin Suppresses Tumor Angiogenesis through NF-κB Pathway Inhibition by Binding to TRAF6

Tumor angiogenesis is essential for tumor progression. The inhibition of tumor angiogenesis is a promising therapy for tumors. Bovine lactoferrin (bLF) has been reported as an anti-tumor agent. However, bLF effects on tumor angiogenesis are not well demonstrated. This study evaluated the inhibitory effects of bLF on tumor angiogenesis in vivo and in vitro. Herein, tumor endothelial cells (TECs) and normal endothelial cells (NECs) were used. Proliferation, migration, tube formation assays, RT-PCR, flow cytometry, Western blotting, siRNA experiments and immunoprecipitation were conducted to clarify the mechanisms of bLF-induced effects. CD-31 immunoexpression was examined in tumor tissues of oral squamous cell carcinoma mouse models with or without Liposomal bLF (LbLF)-administration. We confirmed that bLF inhibited proliferation/migration/tube formation and increased apoptosis in TECs but not NECs. TNF receptor-associated factor 6 (TRAF6), p-p65, hypoxia inducible factor-α (HIF-1α) and vascular endothelial growth factor (VEGF) were highly expressed in TECs. In TECs, bLF markedly downregulated VEGF-A, VEGF receptor (VEGFR) and HIF-1α via the inhibition of p-p65 through binding with TRAF6. Since NECs slightly expressed p-p65, bLF-TRAF-6 binding could not induce detectable changes. Moreover, orally administrated LbLF decreased CD31-positive microvascular density only in TECs. Hence, bLF specifically suppressed tumor angiogenesis through p-p65 inhibition by binding to TRAF6 and suppressing HIF-1α activation followed by VEGF/VEGFR down-regulation. Collectively, bLF can be an anti-angiogenic agent for tumors.

Investigating changes in the post-transcriptional pattern of VEGF and CD146 genes carrying miR-573 in breast cancer cells treated with tamoxifen

BACKGROUND

Recent developments regarding the contribution of microRNAs (miRNAs) to tumor angiogenesis and the oncogenic effects of miRNAs point to their potential role in breast cancer angiogenesis. Tumor-derived exosomes are considered a rich source of miRNAs that can regulate the function of other cells in the tumor microenvironment, including vascular endothelial cells. This study analyzes the effect of tamoxifen chemotherapy on the expression of a key miRNA, miR-573, involved in the angiogenesis of the tumor exosomes and introduces a regulatory link between this miRNA and the CD146 gene associated with the vascular endothelial growth factor (VEGF) messaging pathway.

MATERIALS AND METHODS

MCF-7 breast cancer cells were purchased and cultured in a complete culture medium. These cells were treated with tamoxifen and then their exosomes were extracted from the culture medium. The RNAs of the exosomes were isolated and the expression of miR-573, VEGF, and CD146 genes in the exosomes was investigated using the real-time polymerase chain reaction (PCR) method.

RESULTS

The results of this study showed that tamoxifen treatment increased the expression of miR-573 in exosomes derived from MCF-7 cancer cells. The expression of CD146 and VEGF genes in drug-treated cell exosomes had a downward pattern.

CONCLUSION

The results of this experiment demonstrated that the treatment of breast cancer cells with tamoxifen reduces the expression of VEGF and CD146 by increasing miR-573. Thus, angiogenesis is reduced and, therefore, its anti-tumor effects are applied.

Mechanism of Exosomal LncRNA PART1 in Esophageal Cancer Angiogenesis by Targeting miR-302a-3p/CDC25A Axis

OBJECTIVE

LncRNA PART1 has been confirmed related to multiple cancer bioactivities mediated with vascular endothelial growth factor signaling. Nevertheless, the role of LncRNA PART1 in esophageal cancer induced angiogenesis remains unclear. The present work focused on assessing LncRNA PART1 effects on esophageal cancer-induced angiogenesis and exploring possible mechanisms.

METHODS

Western blot and immunofluorescence were conducted for identifying EC9706 exosomes. MiR-302a-3p and LncRNA PART1 levels were assessed by real-time quantitative polymerase chain reaction. Cell Counting Kit-8, EdU, wound healing, transwell, and tubule information were adopted for detecting human umbilical vein endothelial cell viability, proliferation, migration, invasion, and tubule information, respectively. Starbase software and dual-luciferase reporter were conducted for predicting and judging the expression interrelation of LncRNA PART1 and its potential target-miR-302a-3p. The same methods were carried out for verifying the inhibiting influences of miR-302a-3p upregulation and its potential target-cell division cycle 25 A.

RESULTS

LncRNA PART1 levels were upregulated and related to the overall survival of patients in esophageal cancer. EC9706-Exos accelerated human umbilical vein endothelial cell proliferation, migration, invasion, and tubule formation via LncRNA PART1. LncRNA PART1 served as a sponge of miR-302a-3p, then miR-302a-3p targeted cell division cycle 25 A, and EC9706-Exos accelerated human umbilical vein endothelial cell angiogenesis via LncRNA PART1/ miR-302a-3p/cell division cycle 25 A axis.

CONCLUSION

EC9706-Exos accelerates human umbilical vein endothelial cell angiogenesis via LncRNA PART1/miR-302a-3p/ cell division cycle 25 A axis, indicating EC9706-Exos may act as a promoter of angiogenesis. Our research will contribute to clarify the mechanism of tumor angiogenesis.

Targeting OPA1-Mediated Mitochondrial Fusion Contributed to Celastrol's Anti-Tumor Angiogenesis Effect

Celastrol, an active triterpenoid extracted from one of the most famous traditional Chinese medicines (TCMs), Tripterygium wilfordii Hook.f., is a novel anti-cancer drug with significant anti-angiogenesis activity. However, the exact molecular mechanisms underlying its anti-tumor angiogenesis effect remain unclear. The process of angiogenesis needs lots of energy supply, which mostly derives from mitochondria, the "energy factory" in our body. This study shows that celastrol exerts visible suppression on tumor growth and angiogenesis in a cell-derived xenograft (CDX). Likewise, it reduced the tube formation and migration of human umbilical vein endothelial cells (HUVECs), suppressed the energy metabolism of mitochondria in the Seahorse XF Mito Stress Test, and triggered mitochondrial fragmentation and NF-κB activation. Mechanically, celastrol downregulated the expression of mitochondrial-sharping protein optic atrophy protein 1 (OPA1), which was further estimated by the OPA1 knockdown model of HUVECs. Specifically, celastrol directly suppressed OPA1 at the mRNA level by inhibiting the phosphorylation of STAT3, and stattic (STAT3 inhibitor) showed the same effects on OPA1 suppression and anti-angiogenesis activity. Overall, this study indicates that celastrol inhibits tumor angiogenesis by suppressing mitochondrial function and morphology via the STAT3/OPA1/P65 pathway and provides new insight for mitochondrion-targeted cancer therapy.

The Mutually Mediated Chloride Intracellular Channel Protein 1 (CLIC1) Relationship between Malignant Cells and Tumor Blood Vessel Endothelium Exhibits a Significant Impact on Tumor Angiogenesis, Progression, and Metastasis in Clear Cell Renal Cell Carcinoma (ccRCC)

Background: Overexpression of chloride intracellular channel protein 1 (CLIC1) in tumor cells has been confirmed, but it has received less attention in the tumor blood vessel endothelium. Aim: The assessment of CLIC1 expression in ccRCC tumor blood vessels and its relationship with TNM parameters and tumor cell CLIC1 expression. Methods: CLIC1 immunostaining in ccRCC was evaluated in 50 cases in both malignant cells and tumor blood vessels (CLIC1 microvessel density-CLIC1-MVD) and was correlated with TNM staging parameters. Results: CLIC1-MVD was observed in approximately 65% of cases, and CLIC1 co-localization in both tumor and endothelial cells was observed in 59% of cases. ccRCC was classified into four groups (Classes 0−3) based on the percentage of positive tumor cells, with each group including sub-groups defined by CLIC1 expression in the endothelium. Class 3 (60−100% positive tumor cells) had the highest CLIC1-MVD, with an impact on T and M parameters (p value = 0.007 for T, and p value = 0.006 for M). For cases with CLIC1 intracellular translocation, there was a strong correlation between CLIC1-MVD and M (p value < 0.001). Conclusions: Co-expression of ccRCC tumor and endothelial cells promotes tumor progression and metastasis and should be investigated further as a potential therapeutic target for ccRCC and other human malignancies.

Endothelial-Specific Molecule 1 Inhibition Lessens Productive Angiogenesis and Tumor Metastasis to Overcome Bevacizumab Resistance

The development of drug resistance in malignant tumors leads to disease progression, creating a bottleneck in treatment. Bevacizumab is widely used clinically, and acts by inhibiting angiogenesis to "starve" tumors. Continuous treatment can readily induce rebound proliferation of tumor blood vessels, leading to drug resistance. Previously, we found that the fragment crystallizable (Fc) region of bevacizumab cooperates with the Toll-like receptor-4 (TLR4) ligand to induce M2b polarization in macrophages and secrete tumor necrosis factor-α (TNFα), which promotes immunosuppression, tumor metastasis, and angiogenesis. However, the downstream mechanism underlying TNFα-mediated bevacizumab resistance requires further investigation. Our RNA-Seq analysis results revealed that the expression of endothelial cell specific molecule-1 (ESM1) increased significantly in drug-resistant tumors and promoted metastasis and angiogenesis in vitro and in vivo. Furthermore, TNFα induced the upregulation of ESM1, which promotes metastasis and angiogenesis and regulates matrix metalloprotease-9 (MMP9), vascular endothelial growth factor (VEGF), and delta-like ligand-4 molecules (DLL4). Accordingly, the curative effect of bevacizumab improved by neutralizing ESM1 with high-affinity anti-ESM1 monoclonal antibody 1-2B7 in bevacizumab-resistant mice. This study provides important insights regarding the molecular mechanism by which TNFα-induced ESM1 expression promotes angiogenesis, which is significant for elucidating the mechanism of bevacizumab drug resistance and possibly identifying appropriate biosimilar molecules.

Scoping Review on Platelets and Tumor Angiogenesis: Do We Need More Evidence or Better Analysis?

Platelets are an active component of the tumor microenvironment (TME), involved in the regulation of multiple tumor processes, including angiogenesis. They are generated rich in angiogenic factors in their granules to actively participate in the hemostatic process by megakaryocytes and further enriched in angiogenic factors by all components of the tumor microenvironment to control the angiogenic process because of their preferential relationship with the endothelial component of vessels. In recent decades, the literature has reported a great deal of evidence on the role of platelets in tumor angiogenesis; however, it is unclear whether the number or mean volume of platelets and/or their content and localization in TME may have clinical relevance in the choice and management of therapy for the cancer patient. In this scoping review, we collected and critically reviewed the scientific evidence supporting a close relationship between platelets, cancer, and angiogenesis. The aim of this work was to define the landscape of platelet-activated angiogenesis in cancer progression and analyze what and how much evidence is present in the last 20 years in the literature at both the preclinical and clinical levels, to answer whether platelets could be a useful determinant for analyzing tumor angiogenesis. In conclusion, this scoping review indicates that there is much evidence, both preclinical and clinical, but in the preclinical context, studies demonstrate the direct involvement of platelets in tumor angiogenesis; in the clinical context the evidence is indirect, though strong, and the indication of how and to what extent platelet content contributes to tumor angiogenesis is lacking. So, do we need more evidence or better analysis? More molecular and quali-quantitative data is needed to translate the results obtained in preclinical studies into the clinical setting. This information about platelets, if correlated with tumor type and its biology, including tumor vasculature, type of angiogenesis, and patient characteristics (age, sex, comorbidities, drug treatments for chronic diseases) could be an important pa- rameter for correlating platelet biology to angiogenesis, for personalizing cancer therapy, and for clinical prognosis.

Pentapeptide AYP from Isochrysis Zhanjiangensis Exhibits Antiangiogenic Activity in HT1080 Cells and HUVECs by Suppressing Migration and Invasion In Vitro

Microalgae are important biological sources of marine active peptides and renewable biological resources. Isochrysis zhanjiangensis has been widely used in biological ultrafiltration membranes and aquaculture. However, there are relatively few studies on its component structure and diverse activities. In this study, the mechanism of action of previously isolated pentapeptides (AYP, Ala-Tyr-Ala-Pro-Glu) on inflammation and tumor angiogenesis was evaluated. The results showed that AYP could effectively inhibit the invasion and migration of human umbilical vein endothelial cells (HUVECs) and HT1080 cells by downregulating the expression of MMP-2/-9, independent of cytotoxicity. Especially after 100 μM AYP treatment, the ability to inhibit migration was about 67.7% ± 1.9 for HT1080 cells and 63.6% ± 1.3 for HUVECs, respectively. In addition, the activity of iNOS and COX-2 was decreased by inhibiting the oversecretion of VEGF in HT1080 cells induced by CoCl₂ and the activation of VEGFR-2 in HUVECs and by regulating PI3K/AKT and Ras/MAPK signaling pathways. It can prevent inflammation and block tumor angiogenesis. Therefore, AYP is expected to become a drug or functional food to prevent and treat tumor angiogenesis.

STAT6 Upregulates NRP1 Expression in Endothelial Cells and Promotes Angiogenesis

The role of signal transducer and activator of transcription 6 (STAT6) in tumor growth has been widely recognized. However, its effects on the regulation of angiogenesis remain unclear. In this study, we found that STAT6 promoted angiogenesis, possibly by increasing the expression of neuropilin-1 (NRP1) in endothelial cells (ECs). Both STAT6 inhibitor (AS1517499) and STAT6 siRNA reduced EC proliferation, migration, and tube-formation, accompanied by downregulation of NRP1, an angiogenesis regulator. Furthermore, IL-13 induced activation of STAT6 and then increased NRP1 expression in ECs. IL-13-induced EC migration and tube formation were inhibited by NRP1 siRNA. Luciferase assay and chromatin immunoprecipitation assay demonstrated that STAT6 could directly bind to human NRP1 promoter and increase the promoter activity. In tumor xenograft models, inhibition of STAT6 reduced xenograft growth, tumor angiogenesis, and NRP1 expression in vivo. Overall, these results clarified the novel mechanism by which STAT6 regulates angiogenesis, and suggested that STAT6 may be a potential target for anti-angiogenesis therapy.

Aspartate metabolism in endothelial cells activates the mTORC1 pathway to initiate translation during angiogenesis

Angiogenesis, the active formation of new blood vessels from pre-existing ones, is a complex and demanding biological process that plays an important role in physiological as well as pathological settings. Recent evidence supports cell metabolism as a critical regulator of angiogenesis. However, whether and how cell metabolism regulates endothelial growth factor receptor levels and nucleotide synthesis remains elusive. We here shown in both human cell lines and mouse models that during developmental and pathological angiogenesis, endothelial cells (ECs) use glutaminolysis-derived glutamate to produce aspartate (Asp) via aspartate aminotransferase (AST/GOT). Asp leads to mTORC1 activation which, in turn, regulates endothelial translation machinery for VEGFR2 and FGFR1 synthesis. Asp-dependent mTORC1 pathway activation also regulates de novo pyrimidine synthesis in angiogenic ECs. These findings identify glutaminolysis-derived Asp as a regulator of mTORC1-dependent endothelial translation and pyrimidine synthesis. Our studies may help overcome anti-VEGF therapy resistance by targeting endothelial growth factor receptor translation.

Noncoding RNAs of Extracellular Vesicles in Tumor Angiogenesis: From Biological Functions to Clinical Significance

Extracellular vesicles (EVs) act as multifunctional regulators of intercellular communication and are involved in diverse tumor phenotypes, including tumor angiogenesis, which is a highly regulated multi-step process for the formation of new blood vessels that contribute to tumor proliferation. EVs induce malignant transformation of distinct cells by transferring DNAs, proteins, lipids, and RNAs, including noncoding RNAs (ncRNAs). However, the functional relevance of EV-derived ncRNAs in tumor angiogenesis remains to be elucidated. In this review, we summarized current research progress on the biological functions and underlying mechanisms of EV-derived ncRNAs in tumor angiogenesis in various cancers. In addition, we comprehensively discussed the potential applications of EV-derived ncRNAs as cancer biomarkers and novel therapeutic targets to tailor anti-angiogenic therapy.

Strategies for Remodeling the Tumor Microenvironment Using Active Ingredients of Ginseng-A Promising Approach for Cancer Therapy

The tumor microenvironment (TME) plays a key role in promoting the initiation and progression of tumors, leading to chemoradiotherapy resistance and immunotherapy failure. Targeting of the TME is a novel anti-tumor therapeutic approach and is currently a focus of anti-tumor research. Panax ginseng C. A. Meyer (ginseng), an ingredient of well-known traditional Asia medicines, exerts beneficial anti-tumor effects and can regulate the TME. Here, we present a systematic review that describes the current status of research efforts to elucidate the functions and mechanisms of ginseng active components (including ginsenosides and ginseng polysaccharides) for achieving TME regulation. Ginsenosides have variety effects on TME, such as Rg3, Rd and Rk3 can inhibit tumor angiogenesis; Rg3, Rh2 and M4 can regulate the function of immune cells; Rg3, Rd and Rg5 can restrain the stemness of cancer stem cells. Ginseng polysaccharides (such as red ginseng acidic polysaccharides and polysaccharides extracted from ginseng berry and ginseng leaves) can regulate TME mainly by stimulating immune cells. In addition, we propose a potential mechanistic link between ginseng-associated restoration of gut microbiota and the tumor immune microenvironment. Finally, we describe recent advances for improving ginseng efficacy, including the development of a nano-drug delivery system. Taken together, this review provides novel perspectives on potential applications for ginseng active ingredients as anti-cancer adjuvants that achieve anti-cancer effects by reshaping the tumor microenvironment.

Tumor-Derived Extracellular Vesicles Induce Abnormal Angiogenesis via TRPV4 Downregulation and Subsequent Activation of YAP and VEGFR2

Tumor angiogenesis is initiated and maintained by the tumor microenvironment through secretion of autocrine and paracrine factors, including extracellular vesicles (EVs). Although tumor-derived EVs (t-EVs) have been implicated in tumor angiogenesis, growth and metastasis, most studies on t-EVs are focused on proangiogenic miRNAs and growth factors. We have recently demonstrated that conditioned media from human lung tumor cells (A549) downregulate TRPV4 channels and transform normal endothelial cells to a tumor endothelial cell-like phenotype and induce abnormal angiogenesis in vitro, via t-EVs. However, the underlying molecular mechanism of t-EVs on endothelial cell phenotypic transition and abnormal angiogenesis in vivo remains unknown. Here, we demonstrate that t-EVs downregulate TRPV4 expression post-translationally and induce abnormal angiogenesis by activating Rho/Rho kinase/YAP/VEGFR2 pathways. Further, we demonstrate that t-EVs induce abnormal vessel formation in subcutaneously implanted Matrigel plugs in vivo (independent of tumors), which are characterized by increased VEGFR2 expression and reduced pericyte coverage. Taken together, our findings demonstrate that t-EVs induce abnormal angiogenesis via TRPV4 downregulation-mediated activation of Rho/Rho kinase/YAP/VEGFR2 pathways and suggest t-EVs and TRPV4 as novel targets for vascular normalization and cancer therapy.

Potential Anti-Metastatic Role of the Novel miR-CT3 in Tumor Angiogenesis and Osteosarcoma Invasion

Osteosarcoma (OS) is the most common primary bone tumor mainly occurring in young adults and derived from primitive bone-forming mesenchyme. OS develops in an intricate tumor microenvironment (TME) where cellular function regulated by microRNAs (miRNAs) may affect communication between OS cells and the surrounding TME. Therefore, miRNAs are considered potential therapeutic targets in cancer and one of the goals of research is to accurately define a specific signature of a miRNAs, which could reflect the phenotype of a particular tumor, such as OS. Through NGS approach, we previously found a specific molecular profile of miRNAs in OS and discovered 8 novel miRNAs. Among these, we deepen our knowledge on the fifth candidate renamed now miR-CT3. MiR-CT3 expression was low in OS cells when compared with human primary osteoblasts and healthy bone. Through TargetScan, VEGF-A was predicted as a potential biological target of miR-CT3 and luciferase assay confirmed it. We showed that enforced expression of miR-CT3 in two OS cell lines, SAOS-2 and MG-63, reduced expression of VEGF-A mRNA and protein, inhibiting tumor angiogenesis. Enforced expression of miR-CT3 also reduced OS cell migration and invasion as confirmed by soft agar colony formation assay. Interestingly, we found that miR-CT3 behaves inducing the activation of p38 MAP kinase pathway and modulating the epithelial-mesenchymal transition (EMT) proteins, in particular reducing Vimentin expression. Overall, our study highlights the novel role of miR-CT3 in regulating tumor angiogenesis and progression in OS cells, linking also to the modulation of EMT proteins.

Rosa hybrida Petal Extract Exhibits Antitumor Effects by Abrogating Tumor Progression and Angiogenesis in Bladder Cancer Both In Vivo and In Vitro

The edible Rosa hybrida (RH) petal is utilized in functional foods and cosmetics. Although the biological function of RH petal extract is known, mechanism of action studies involving tumor-associated angiogenesis have not yet been reported. Herein, we investigated the regulatory effect of the ethanol extract of RH petal (EERH) on tumor growth and tumor angiogenesis against bladder cancer. EERH treatment inhibited the bladder carcinoma T24 cell and 5637 cell proliferation because of G₁-phase cell cycle arrest by inducing p21WAF1 expression and reducing cyclins/CDKs level. EERH regulated signaling pathways differently in both cells. EERH-stimulated suppression of T24 and 5637 cell migration and invasion was associated with the decline in transcription factor-mediated MMP-9 expression. EERH oral administration to xenograft mice reduced tumor growth. Furthermore, no obvious toxicity was observed in acute toxicity test. Decreased CD31 levels in EERH-treated tumor tissues led to examine the angiogenic response. EERH alleviated VEGF-stimulated tube formation and proliferation by downregulating the VEGFR2/eNOS/AKT/ERK1/2 cascade in HUVECs. EERH impeded migration and invasion of VEGF-induced HUVECs, which is attributed to the repressed MMP-2 expression. Suppression of neo-microvessel sprouting, induced by VEGF, was verified by treatment with EERH using the ex vivo aortic ring assay. Finally, kaempferol was identified as the main active compound of EERH. The present study demonstrated that EERH may aid the development of antitumor agents against bladder cancer.

New Insights Into the Regulatory Roles of Extracellular Vesicles in Tumor Angiogenesis and Their Clinical Implications

Angiogenesis is required for tumor growth and development. Extracellular vesicles (EVs) are important signaling entities that mediate communication between diverse types of cells and regulate various cell biological processes, including angiogenesis. Recently, emerging evidence has suggested that tumor-derived EVs play essential roles in tumor progression by regulating angiogenesis. Thousands of molecules are carried by EVs, and the two major types of biomolecules, noncoding RNAs (ncRNAs) and proteins, are transported between cells and regulate physiological and pathological functions in recipient cells. Understanding the regulation of EVs and their cargoes in tumor angiogenesis has become increasingly important. In this review, we summarize the effects of tumor-derived EVs and their cargoes, especially ncRNAs and proteins, on tumor angiogenesis and their mechanisms, and we highlight the clinical implications of EVs in bodily fluids as biomarkers and as diagnostic, prognostic, and therapeutic targets in cancer patients.

A New Antitumor Direction: Tumor-Specific Endothelial Cells

Targeting tumor blood vessels is an important strategy for tumor therapies. At present, antiangiogenic drugs are known to have significant clinical effects, but severe drug resistance and side effects also occur. Therefore, new specific targets for tumor and new treatment methods must be developed. Tumor-specific endothelial cells (TECs) are the main targets of antiangiogenic therapy. This review summarizes the differences between TECs and normal endothelial cells, assesses the heterogeneity of TECs, compares tumorigenesis and development between TECs and normal endothelial cells, and explains the interaction between TECs and the tumor microenvironment. A full and in-depth understanding of TECs may provide new insights for specific antitumor angiogenesis therapies.

Neutrophil and Natural Killer Cell Interactions in Cancers: Dangerous Liaisons Instructing Immunosuppression and Angiogenesis

The tumor immune microenvironment (TIME) has largely been reported to cooperate on tumor onset and progression, as a consequence of the phenotype/functional plasticity and adaptation capabilities of tumor-infiltrating and tumor-associated immune cells. Immune cells within the tumor micro (tissue-local) and macro (peripheral blood) environment closely interact by cell-to-cell contact and/or via soluble factors, also generating a tumor-permissive soil. These dangerous liaisons have been investigated for pillars of tumor immunology, such as tumor associated macrophages and T cell subsets. Here, we reviewed and discussed the contribution of selected innate immunity effector cells, namely neutrophils and natural killer cells, as "soloists" or by their "dangerous liaisons", in favoring tumor progression by dissecting the cellular and molecular mechanisms involved.

Donafenib-Loaded Callispheres Beads Embolization in a VX2 Liver Tumor: Investigating Efficacy, Safety, and Improvement of Tumor Angiogenesis After Embolization

Objective

To investigate the efficiency and safety of callispheres beads loaded with donafenib (DCBs) for embolization in a VX2 liver tumor, as well as the improvement of tumor angiogenesis following embolization.

Methods

Forty New Zealand white rabbit VX2 liver tumors were treated with four different drugs via the hepatic artery: NS (normal saline), CB (blank callispheres beads), ACB (adriamycin-loaded callispheres beads) and DCB (DCBs). Hematoxylin-eosin staining was performed to assess tumor necrosis, while MRI was employed to detect the changes in tumor size. The safety was evaluated by the liver and kidney function parameters, and the immunofluorescence and immunohistochemical staining were performed to reflect the tumor hypoxia and tumor angiogenesis following embolization.

Results

The DCB group had the smallest tumor growth rate, but the tumor necrosis rate was the highest of the four groups. Compared to the CB and ACB groups, the DCB group did not aggravate the liver damage and had no influence on kidney function. The staining results showed that, although the tumor hypoxia deteriorated after DCBs embolization, the expression of VEGF (vascular endothelial growth factor) reduced, thus inhibiting tumor angiogenesis.

Conclusion

DCB administration via hepatic artery is an effective and safe treatment for a preclinical liver cancer model, with the unique benefit of suppressing tumor angiogenesis following embolization.

Propensity for Early Metastatic Spread in Breast Cancer: Role of Tumor Vascularization Features and Tumor Immune Infiltrate

Breast cancer is a complex and highly heterogeneous disease consisting of various subtypes. It is classified into human epidermal growth receptor 2 (HER-2)-enriched, luminal A, luminal B and basal-like/triple negative (TNBC) breast cancer, based on histological and molecular features. At present, clinical decision-making in breast cancer is focused only on the assessment of tumor cells; nevertheless, it has been recognized that the tumor microenvironment (TME) plays a critical biologic role in breast cancer. This is constituted by a large group of immune and non-immune cells, but also by non-cellular components, such as several cytokines. TME is deeply involved in angiogenesis, immune-evasion strategies, and propensity for early metastatic spread, impacting on prognosis and prediction of response to specific treatments. In this review, we focused our attention on the early morphological changes of tumor microenvironment (tumor vasculature features, presence of immune and non-immune cells infiltrating the stroma, levels of cytokines) during breast cancer development. At the same time, we correlate these characteristics with early metastatic propensity (defined as synchronous metastasis or early recurrence) with particular attention to breast cancer subtypes.

Real-Time Longitudinal Evaluation of Tumor Blood Vessels Using a Compact Preclinical Fluorescence Imaging System

Tumor angiogenesis is enhanced in all types of tumors to supply oxygen and nutrients for their growth and metastasis. With the development of anti-angiogenic drugs, the importance of technology that closely monitors tumor angiogenesis has also been emerging. However, to date, the technology for observing blood vessels requires specialized skills with expensive equipment, thereby limiting its applicability only to the laboratory setting. Here, we used a preclinical optical imaging system for small animals and, for the first time, observed, in real time, the entire process of blood vessel development in tumor-bearing mice injected with indocyanine green. Time-lapse sequential imaging revealed blood vessel volume and blood flow dynamics on a microscopic scale. Upon analyzing fluorescence dynamics at each stage of tumor progression, vessel volume and blood flow were found to increase as the tumor developed. Conversely, these vascular parameters decreased when the mice were treated with angiogenesis inhibitors, which suggests that the effects of drugs targeting angiogenesis can be rapidly and easily screened. The results of this study may help evaluate the efficacy of angiogenesis-targeting drugs by facilitating the observation of tumor blood vessels easily in a laboratory unit without large and complex equipment.

Natural Products: A Promising Therapeutics for Targeting Tumor Angiogenesis

Tumor-associated angiogenesis is a key target for anti-cancer therapy. The imbalance between pro-angiogenic and anti-angiogenic signals elicited by tumor cells or tumor microenvironment always results in activating "angiogenic switch". Tumor angiogenesis functions in multi-aspects of tumor biology, including endothelial cell apoptosis, tumor metastasis, and cancer stem cell proliferation. Numerous studies have indicated the important roles of inexpensive and less toxic natural products in targeting tumor angiogenesis-associated cytokines and apoptotic signaling pathways. Our current knowledge of tumor angiogenesis is based mainly on experiments performed on cells and animals, so we summarized the well-established models for angiogenesis both in vitro and in vivo. In this review, we classified and summarized the anti-angiogenic natural agents (Polyphenols, Polysaccharides, Alkaloids, Terpenoids, Saponins) in targeting various tumor types according to their chemical structures at present, and discussed the mechanistic principles of these natural products on regulating angiogenesis-associated cytokines and apoptotic signaling pathways. This review is to help understanding the recent progress of natural product research for drug development on anti-tumor angiogenesis.

SIRT1-mediated deacetylation of FOXO3a transcription factor supports pro-angiogenic activity of interferon-deficient tumor-associated neutrophils

Angiogenesis plays an important role during tumor growth and metastasis. We could previously show that Type I interferon (IFN)-deficient tumor-associated neutrophils (TANs) show strong pro-angiogenic activity, and stimulate tumor angiogenesis and growth. However, the exact mechanism responsible for their pro-angiogenic shift is not clear. Here, we set out to delineate the molecular mechanism and factors regulating pro-angiogenic properties of neutrophils in the context of Type I IFN availability. We demonstrate that neutrophils from IFN-deficient (Ifnar1^-/- ) mice efficiently release pro-angiogenic factors, such as VEGF, MMP9 or BV8, and thus significantly support the vascular normalization of tumors by increasing the maturation of perivascular cells. Mechanistically, we could show here that the expression of pro-angiogenic factors in neutrophils is controlled by the transcription factor forkhead box protein O3a (FOXO3a), which activity depends on its post-translational modifications, such as deacetylation or phosphorylation. In TANs isolated from Ifnar1^-/- mice, we observe significantly elevated SIRT1, resulting in SIRT1-mediated deacetylation of FOXO3a, its nuclear retention and activation. Activated FOXO3a supports in turn the transcription of pro-angiogenic genes in TANs. In the absence of SIRT1, or after its inhibition in neutrophils, elevated kinase MEK/ERK and PI3K/AKT activity is observed, leading to FOXO3a phosphorylation, cytoplasmic transfer and inactivation. In summary, we have found that FOXO3a is a key transcription factor controlling the angiogenic switch of neutrophils. Post-translational FOXO3a modifications regulate its transcriptional activity and, as a result, the expression of pro-angiogenic factors supporting development of vascular network in growing tumors. Therefore, targeting FOXO3a activity could provide a novel strategy of antiangiogenic targeted therapy for cancer.

The Dual Effect of the BMP9-ALK1 Pathway in Blood Vessels: An Opportunity for Cancer Therapy Improvement?

Simple Summary

The modulation of tumor blood vessels is a great opportunity for improving cancer therapies. Understanding the cellular and molecular players that regulate the biology of tumor blood vessels and tumor angiogenesis is necessary for the development of new anti-tumor strategies. Bone morphogenetic protein 9 (BMP9) is a circulating factor with multiple effects in vascular biology through its receptor activin receptor-like kinase 1 (ALK1). In this review, we give an overview of the possible benefits of modulating BMP9–ALK1 functions for cancer therapy improvement.

Abstract

The improvement of cancer therapy efficacy, the extension of patient survival and the reduction of adverse side effects are major challenges in cancer research. Targeting blood vessels has been considered a promising strategy in cancer therapy. Since the tumor vasculature is disorganized, leaky and triggers immunosuppression and tumor hypoxia, several strategies have been studied to modify tumor vasculature for cancer therapy improvement. Anti-angiogenesis was first described as a mechanism to prevent the formation of new blood vessels and prevent the oxygen supply to tumor cells, showing numerous limitations. Vascular normalization using low doses of anti-angiogenic drugs was purposed to overcome the limitations of anti-angiogenic therapies. Other strategies such as vascular promotion or the induction of high endothelial venules are being studied now to improve cancer therapy. Bone morphogenetic protein 9 (BMP9) exerts a dual effect through the activin receptor-like kinase 1 (ALK1) receptor in blood vessel maturation or activation phase of angiogenesis. Thus, it is an interesting pathway to target in combination with chemotherapies or immunotherapies. This review manuscript explores the effect of the BMP9–ALK1 pathway in tumor angiogenesis and the possible usefulness of targeting this pathway in anti-angiogenesis, vascular normalization or vascular promotion therapies.

Non-coding RNAs in Regulating Tumor Angiogenesis

Non-coding RNAs (ncRNAs) are RNAs that do not encode proteins, but perform biological functions in various physiological and pathological processes, including cancer formation, inflammation, and neurological diseases. Tumor blood vessels are a key target for cancer management. A number of factors regulate the angiogenesis of malignant tumors. NcRNAs participate in the regulation of tumor angiogenesis. Abnormal expression of ncRNAs act as tumor suppressors or oncogenes to affect the development of tumors. In this review we summarized the biological functions of ncRNAs, and discussed its regulatory mechanisms in tumor angiogenesis. This article will provide new insights for the research of ncRNAs in tumor angiogenesis.