Vascular mimicry: changing the therapeutic paradigms in cancer

Functional roles of microRnas in vasculogenic mimicry and resistance to therapy in human cancers: an update

INTRODUCTION

Vasculogenic mimicry (VM) alludes to the ability of cancer cells to organize on three-dimensional channels-like structures to obtain nutrients and oxygen. This mechanism confers an aggressive phenotype, metastatic potential, and resistance to chemotherapy resulting in a poor prognosis. Recent studies have been focused on the identification of microRNAs (miRNAs) that regulate the VM representing potential therapeutic targets in cancer.

AREAS COVERED

A overview of the roles of miRNAs on VM development, and their functional relationships with tumor microenvironment. The functions of cancer stem-like cells in VM, and resistance to therapy are also discussed. Moreover, the modulation of VM by natural compounds is explored. The clinical significance of deregulated miRNAs as potential therapeutic targets in tumors showing VM is further highlighted.

EXPERT OPINION

The miRNAs are regulators of protein-encoding genes involved in VM; however, their specific expression signatures with clinical value in large cohorts of patients have not been established yet. We considered that genomic profiling of miRNAs could be useful to define some hallmarks of tumors such as stemness, drug resistance and VM in cancer patients. However, additional studies are needed to establish the relevant role of miRNAs as effective therapeutic targets in tumors that have developed VM.

LIFU/MMP-2 dual-responsive release of repurposed drug disulfiram from nanodroplets for inhibiting vasculogenic mimicry and lung metastasis in triple-negative breast cancer

BACKGROUND

Vasculogenic mimicry (VM), when microvascular channels are formed by cancer cells independent of endothelial cells, often occurs in deep hypoxic areas of tumors and contributes to the aggressiveness and metastasis of triple-negative breast cancer (TNBC) cells. However, well-developed VM inhibitors exhibit inadequate efficacy due to their low drug utilization rate and limited deep penetration. Thus, a cost-effective VM inhibition strategy needs to be designed for TNBC treatment.

RESULTS

Herein, we designed a low-intensity focused ultrasound (LIFU) and matrix metalloproteinase-2 (MMP-2) dual-responsive nanoplatform termed PFP@PDM-PEG for the cost-effective and efficient utilization of the drug disulfiram (DSF) as a VM inhibitor. The PFP@PDM-PEG nanodroplets effectively penetrated tumors and exhibited substantial accumulation facilitated by PEG deshielding in a LIFU-mediated and MMP-2-sensitive manner. Furthermore, upon exposure to LIFU irradiation, DSF was released controllably under ultrasound imaging guidance. This secure and controllable dual-response DSF delivery platform reduced VM formation by inhibiting COL1/pro-MMP-2 activity, thereby significantly inhibiting tumor progression and metastasis.

CONCLUSIONS

Considering the safety of the raw materials, controlled treatment process, and reliable repurposing of DSF, this dual-responsive nanoplatform represents a novel and effective VM-based therapeutic strategy for TNBC in clinical settings.

Pan-cancer dissection of vasculogenic mimicry characteristic to provide potential therapeutic targets

Introduction

Vasculogenic mimicry (VM) represents a novel form of tumor angiogenesis that is associated with tumor invasiveness and drug resistance. However, the VM landscape across cancer types remains poorly understood. In this study, we elucidate the characterizations of VM across cancers based on multi-omics data and provide potential targeted therapeutic strategies.

Methods

Multi-omics data from The Cancer Genome Atlas was used to conduct comprehensive analyses of the characteristics of VM related genes (VRGs) across cancer types. Pan-cancer vasculogenic mimicry score was established to provide a depiction of the VM landscape across cancer types. The correlation between VM and cancer phenotypes was conducted to explore potential regulatory mechanisms of VM. We further systematically examined the relationship between VM and both tumor immunity and tumor microenvironment (TME). In addition, cell communication analysis based on single-cell transcriptome data was used to investigate the interactions between VM cells and TME. Finally, transcriptional and drug response data from the Genomics of Drug Sensitivity in Cancer database were utilized to identify potential therapeutic targets and drugs. The impact of VM on immunotherapy was also further clarified.

Results

Our study revealed that VRGs were dysregulated in tumor and regulated by multiple mechanisms. Then, VM level was found to be heterogeneous among different tumors and correlated with tumor invasiveness, metastatic potential, malignancy, and prognosis. VM was found to be strongly associated with epithelial-mesenchymal transition (EMT). Further analyses revealed cancer-associated fibroblasts can promote EMT and VM formation. Furthermore, the immune-suppressive state is associated with a microenvironment characterized by high levels of VM. VM score can be used as an indicator to predict the effect of immunotherapy. Finally, seven potential drugs targeting VM were identified.

Conclusion

In conclusion, we elucidate the characteristics and key regulatory mechanisms of VM across various cancer types, underscoring the pivotal role of CAFs in VM. VM was further found to be associated with the immunosuppressive TME. We also provide clues for the research of drugs targeting VM. Our study provides an initial overview and reference point for future research on VM, opening up new avenues for therapeutic intervention.

Rationale design and synthesis of new apoptotic thiadiazole derivatives targeting VEGFR-2: computational and in vitro studies

This work presents the synthesis and in vitro, and in silico analyses of new thiadiazole derivatives that are designed to mimic the pharmacophoric characteristics of vascular endothelial growth factor receptor-2 (VEGFR-2) inhibitors. A comprehensive evaluation of the inhibitory properties of the synthesized thiadiazole derivatives against the cancer cell lines MCF-7 and HepG2 identified several auspicious candidates. Among them, compound 14 showed remarkably low IC50 values of 0.04 μM and 0.18 μM against MCF-7 and HepG2, respectively. VEGFR-2 inhibitory evaluation of compound 14 revealed a promising IC50 value in the nanomolar range (103 nM). Further examination of the cell cycle revealed that compound 14 has the ability to stop the progression of the cell cycle in MCF-7 cells via G0-G1 phase arrest. Interestingly, compound 14 also demonstrated a noteworthy pro-apoptotic effect in MCF-7 cells, with notable increases in early apoptosis (16.53%) and late apoptosis (29.57%), along with a slight increase in the population of necrotic cells (5.95%). Furthermore, compound 14 showed a significant drop in MCF-7 cells' ability to migrate and heal wounds. Additionally, compound 14 promoted apoptosis by boosting BAX (6-fold) while lowering Bcl-2 (6.2-fold). The binding affinities of the synthesized candidates to their target (VEGFR-2) were confirmed by computational investigations, including molecular docking, principal component analysis of trajectories (PCAT), and molecular dynamics (MD) simulations. Additionally, compound 14's stability and reactivity were investigated using density functional theory (DFT). These thorough results highlight compound 14's potential as a lead contender for additional research in the creation of anticancer drugs that target VEGFR-2. This work establishes a foundation for promising thiadiazole derivatives for future therapeutic developments in anticancer- and angiogenesis-related scientific fields.

Computer-assisted drug discovery (CADD) of an anti-cancer derivative of the theobromine alkaloid inhibiting VEGFR-2

VEGFR-2 is a significant target in cancer treatment, inhibiting angiogenesis and impeding tumor growth. Utilizing the essential pharmacophoric structural properties, a new semi-synthetic theobromine analogue (T-1-MBHEPA) was designed as VEGFR-2 inhibitor. Firstly, T-1-MBHEPA's stability and reactivity were indicated through several DFT computations. Additionally, molecular docking, MD simulations, MM-GPSA, PLIP, and essential dynamics (ED) experiments suggested T-1-MBHEPA's strong binding capabilities to VEGFR-2. Its computational ADMET profiles were also studied before the semi-synthesis and indicated a good degree of drug-likeness. T-1-MBHEPA was then semi-synthesized to evaluate the design and the in silico findings. It was found that, T-1-MBHEPA inhibited VEGFR-2 with an IC50 value of 0.121 ± 0.051 µM, as compared to sorafenib which had an IC50 value of 0.056 µM. Similarly, T-1-MBHEPA inhibited the proliferation of HepG2 and MCF7 cell lines with IC50 values of 4.61 and 4.85 µg/mL respectively - comparing sorafenib's IC50 values which were 2.24 µg/mL and 3.17 µg/mL respectively. Interestingly, T-1-MBHEPA revealed a noteworthy IC50 value of 80.0 µM against the normal cell lines exhibiting exceptionally high selectivity indexes (SI) of 17.4 and 16. 5 against the examined cell lines, respectively. T-1-MBHEPA increased the percentage of apoptotic MCF7 cells in early and late stages, respectively, from 0.71 % to 7.22 % and from 0.13 % to 2.72 %, while the necrosis percentage was increased to 11.41 %, in comparison to 2.22 % in control cells. Furthermore, T-1-MBHEPA reduced the production of pro-inflammatory cytokines TNF-α and IL-2 in the treated MCF7 cells by 33 % and 58 %, respectively indicating an additional anti-angiogenic mechanism. Also, T-1-MBHEPA decreased significantly the potentialities of MCF7 cells to heal and migrate from 65.9 % to 7.4 %. Finally, T-1-MBHEPA's oral treatment didn't show toxicity on the liver function (ALT and AST) and the kidney function (creatinine and urea) levels of mice.

Roles of circRNAs in regulating the tumor microenvironment

CircRNAs, a type of non-coding RNA widely present in eukaryotic cells, have emerged as a prominent focus in tumor research. However, the functions of most circRNAs remain largely unexplored. Known circRNAs exert their regulatory roles through various mechanisms, including acting as microRNA sponges, binding to RNA-binding proteins, and functioning as transcription factors to modulate protein translation and coding. Tumor growth is not solely driven by gene mutations but also influenced by diverse constituent cells and growth factors within the tumor microenvironment (TME). As crucial regulators within the TME, circRNAs are involved in governing tumor growth and metastasis. This review highlights the role of circRNAs in regulating angiogenesis, matrix remodeling, and immunosuppression within the TME. Additionally, we discuss current research on hypoxia-induced circRNAs production and commensal microorganisms' impact on the TME to elucidate how circRNAs influence tumor growth while emphasizing the significance of modulating the TME.

Vascular Progenitor Cells: From Cancer to Tissue Repair

Vascular progenitor cells are activated to repair and form a neointima following vascular damage such as hypertension, atherosclerosis, diabetes, trauma, hypoxia, primary cancerous lesions and metastases as well as catheter interventions. They play a key role not only in the resolution of the vascular lesion but also in the adult neovascularization and angiogenesis sprouting (i.e., the growth of new capillaries from pre-existing ones), often associated with carcinogenesis, favoring the formation of metastases, survival and progression of tumors. In this review, we discuss the biology, cellular plasticity and pathophysiology of different vascular progenitor cells, including their origins (sources), stimuli and activated pathways that induce differentiation, isolation and characterization. We focus on their role in tumor-induced vascular injury and discuss their implications in promoting tumor angiogenesis during cancer proliferation and migration.

The Antiangiogenic and Antitumor Effects of Scoparasin B in Non-Small-Cell Lung Cancer

Angiogenesis and vasculogenic mimicry (VM) are crucial for the growth and metastasis of non-small-cell lung cancer (NSCLC). Most tumor angiogenesis inhibitors mainly target endothelial cell-mediated angiogenesis, ignoring tumor-cell-mediated VM and frequently leading to tumor recurrence and metastasis. Thus, development of bioactive molecules interfering with both tumor angiogenesis and VM is necessary. Identifying novel angiogenesis inhibitors from natural products is a promising strategy. Scoparasin B, a pimarane diterpene extracted from a marine-derived fungus, Eutypella sp. F0219, has an antibacterial effect. However, its effect on angiogenesis and VM remains unexplored. In this study, we first certified that scoparasin B showed a strong inhibition effect on angiogenesis and the VM process in vitro and ex vivo. Moreover, scoparasin B prominently impeded tumor growth, angiogenesis, and VM in an NCI-H1299 xenograft model. Further study revealed that scoparasin B restrained tumor angiogenesis and VM by reducing the VEGF-A level and suppressing the VEGF-A/VEGFR2 signaling pathway. This study first demonstrated scoparasin B inhibited tumor angiogenesis, VM, and tumor growth of NSCLC and revealed its underlying mechanism. These new findings further support the potential of scoparasin B as a novel angiogenesis inhibitor and give a hint for further exploring potential angiogenesis inhibitors from natural products.

Xanthomicrol: Effective therapy for cancer treatment

Cancer treatment is one of the main challenges of global health. For decades, researchers have been trying to find anti-cancer compounds with minimal side effects. In recent years, flavonoids, as a group of polyphenolic compounds, have attracted the attention of researchers due to their beneficial effects on health. Xanthomicrol is one of the flavonoids that has the ability to inhibit growth, proliferation, survival and cell invasion and ultimately tumor progression. Xanthomicrol, as active anti-cancer compounds, can be effective in the prevention and treatment of cancer. Therefore, the use of flavonoids can be suggested as a treatment along with other medicinal agents. It is obvious that additional investigations in cellular levels and animal models are still needed. In this review article, the effects of xanthomicrol on various cancers have been reviewed.

Targeting cancer drug resistance utilizing organoid technology

Cancer organoids generated from 3D in vitro cell cultures have contributed to the study of drug resistance. Maintenance of genomic and transcriptomic similarity between organoids and parental cancer allows organoids to have the ability of accurate prediction in drug resistance testing. Protocols of establishing therapy-sensitive and therapy-resistant organoids are concluded in two aspects, which are generated directly from respective patients' cancer and by induction of anti-cancer drug. Genomic and transcriptomic analyses and gene editing have been applied to organoid studies to identify key targets in drug resistance and FGFR3, KHDRBS3, lnc-RP11-536 K7.3 and FBN1 were found to be key targets. Furthermore, mechanisms contributing to resistance have been identified, including metabolic adaptation, activation of DNA damage response, defects in apoptosis, reduced cellular senescence, cellular plasticity, subpopulation interactions and gene fusions. Additionally, cancer stem cells (CSCs) have been verified to be involved in drug resistance utilizing organoid technology. Reversal of drug resistance can be achieved by targeting key genes and CSCs in cancer organoids. In this review, we summarize applications of organoids to cancer drug resistance research, indicating prospects and limitations.

Nano-composite hydrogels of Cu-Apa micelles for anti-vasculogenic mimicry

Vasculogenic mimicry (VM) describes the phenomenon whereby fluid-conducting vessels are formed by highly invasive tumour cells, which supply blood to tumours during their early growth stages. Single antiangiogenic agents have limited inhibitory effects on VM, therefore, a multi-pathway anti-VM strategy is required. In this study, Apatinib (Apa) was coordinated with Cu²⁺ to form a Cu-Apa copper complex. The latter was loaded into oligo-hyaluronic acid (HA) polymeric micelles (HA-Chol) and subsequently embedded in Astragalus polysaccharide-based in situ hydrogels (APsGels) to generate Cu-Apa/HA-Chol@APsGels. In this system, Cu-Apa exerts the combined effects of Cu²⁺ and Apa to inhibit VM; HA-Chol micelles achieve targeted drug delivery and enhance endocytosis efficiency; APsGels realise sustained release of the drugs to ensure an anti-VM effect. This system demonstrated improved VM inhibition with low cytotoxicity and high biocompatibility, wound healing, and transwell invasion in three-dimensional cell cultured VM. Moreover, this system significantly inhibited VM formation and melanoma growth in a mouse tumour transplantation model. This study provides an effective strategy for inhibiting VM.

Increased expression of androgen receptor and PSA genes in LNCaP (prostate cancer) cell line due to high concentrations of EGCG, an active ingredient in green tea

OBJECTIVES

Androgen receptor (AR) play a key role in the onset and progression of prostate cancer. Epigallocatechin-3-gallate (EGCG) is a polyphenolic compound and the active ingredient in green tea, which is involved in modulating gene expression through epigenetic alterations. Previous studies have shown that EGCG at low concentrations reduces the expression of AR and prostate-specific antigen (PSA) in the LNCaP cell line of prostate cancer. In this study, the effect of higher EGCG concentrations on AR and PSA expression in LNCaP prostate cancer cell line was investigated.

METHODS

In this study, LNCaP prostate cancer cell line was used and after MTT test, concentrations of 40, 60 and 80 μg/mL EGCG were used for treatment. Then, the expression of AR and PSA genes was evaluated by RT-PCR. AR protein expression was also assessed by Western blotting.

RESULTS

The present study showed that treatment of LNCaPs cells by EGCG reduces cell proliferation. The IC50 value was 42.7 μg/mL under experimental conditions. It was also observed that EGCG at concentrations of 40 and 80 μg/mL increased the expression of AR and PSA (p<0.05).

CONCLUSIONS

The present study showed that the effect of EGCG on AR expression was different at different concentrations, so that unlike previous studies, higher concentrations of EGCG (80 and 40 μg/mL) increased AR and PSA expression. It seems that due to the toxic effects of EGCG in high concentrations on cancer cells and the possibility of its effect on normal cells, more caution should be exercised in its use.

Potential tumor marker for hepatocellular carcinoma identification: PI3K and pro-inflammatory cytokines (TGF-β, IL-1, and IL-6)

OBJECTIVES

Hepatocellular carcinoma (HCC), the most common form of liver cancer, is a leading cause of tumor-associated mortality worldwide. Diagnosis based upon non-invasive criteria is currently challenged by the need for molecular information that requires tissue or liquid biopsies. The progression of HCC is often associated with chronic inflammation, expression levels of inflammatory mediators, chemokine, and cytokines. In this study, we try to evaluate the PI3K and pro-inflammatory cytokines, TGF-β, IL-1, and IL-6 expression level in patients with liver cancer.

MATERIALS AND METHODS

The kupffer cells were isolated from patient's specimens. Real-time PCR was applied to evaluate the expression level of PI3K in cell lines or tumors. The concentrations of TGF-β, IL-1, and IL-6 were measured by the quantitative ELISA kit.

RESULTS

PI3K mRNA expression in cancer cells was increased markedly vs. normal cells. The ELISA results demonstrated over expression of TGF-β, IL-1, and IL-6 in patients and positive correlation between tumor size and stage.

DISCUSSION

This study suggests that targeting the expression level of PI3K and pro-inflammatory chemokine and cytokines, TGF-β, IL-1, and IL-6, may be a potential diagnostic strategy in HCC patients.

A concise review of VEGF, PDGF, FGF, Notch, angiopoietin, and HGF signalling in tumor angiogenesis with a focus on alternative approaches and future directions

Angiogenesis forms new vessels from existing ones. Abnormal angiogenesis, which is what gives tumor microenvironments their distinctive features, is characterised by convoluted, permeable blood vessels with a variety of shapes and high perfusion efficiency. Tumor angiogenesis controls cancer growth by allowing invasion and metastasis and is highly controlled by signalling networks. Therapeutic techniques targeting VEGF, PDGF, FGF Notch, Angiopoietin, and HGF signalling restrict the tumor's vascular supply. Numerous pathways regulate angiogenesis, and when one of those processes is blocked, the other pathways may step in to help. VEGF signalling inhibition alone has limits as an antiangiogenic therapy, and additional angiogenic pathways such as FGF, PDGF, Notch, angiopoietin, and HGF are important. For the treatment of advanced solid tumors, there are also new, emerging medicines that target multiple angiogenic pathways. Recent therapies block numerous signalling channels concurrently. This study focuses on 'alternative' methods to standard antiangiogenic medicines, such as cyclooxygenase-2 blocking, oligonucleotide binding complementary sites to noncoding RNAs to regulate mRNA target, matrix metalloproteinase inhibition and CRISPR/Cas9 based gene edition and dissecting alternative angiogenesis mechanism in tumor microenvironment.

Harmaline downregulates angiogenesis markers and suppresses the growth of 4T1 breast cancer cells in vivo and in vitro

The anti-angiogenic effects of harmaline, an alkaloid with emerging anti-tumor properties, are under investigation. In the present study, the effects of different doses of harmaline, either alone or in combination with doxorubicin (DOX), were assessed in mice models of breast tumor. Breast tumors were created by the subcutaneous injection of 4T1 cells into Balb/c mice. The mice received either normal saline, harmaline alone (10, 20, or 30 mg/kg), or harmaline (20 mg/kg) + DOX (10 mg/kg). Immunohistochemistry, ELISA, and real-time PCR were conducted to measure target parameters. Harmaline significantly increased tumor cells' sensitivity to DOX as confirmed by a significantly reduced tumor volume in the harmaline + DOX group after 24 days (P < 0.05). Also, the levels of Ki-67 (P < 0.001), MMP-2 (P < 0.001), and VEGF (P < 0.001) significantly decreased while the level of E-cadherin increased (P < 0.001) in the tumor tissues of the mice treated with 20 or 30 mg/kg harmaline or harmaline (20 mg/kg) + DOX (10 mg/kg) compared to the control group. There was a significant reduction in the serum level of IL-4 in tumor-bearing mice treated with harmaline (P < 0.05), and IFN-γ serum level was significantly augmented in all experimental groups compared to the control group (P < 0.05). The genes encoding VEGF, VEGF receptor 2, CD105, and COX2 were significantly down-regulated (P < 0.05 for all) in harmaline-treated (either alone or in combination with DOX) mice. In conclusion, harmaline seems to have the potential to be used as an anticancer agent for treating breast cancer.

Reassessing vascular endothelial growth factor (VEGF) in anti-angiogenic cancer therapy

Vascularization is fundamental to the growth and spread of tumor cells to distant sites. As a consequence, angiogenesis, the sprouting of new blood vessels from existing ones, is a characteristic trait of cancer. In 1971, Judah Folkman postulated that tumour growth is angiogenesis dependent and that by cutting off blood supply, a neoplastic lesion could be potentially starved into remission. Decades of research have been devoted to understanding the role that vascular endothelial growth factor (VEGF) plays in tumor angiogenesis, and it has been identified as a significant pro-angiogenic factor that is frequently overexpressed within a tumor mass. Today, anti-VEGF drugs such as Sunitinib, Sorafenib, Axitinib, Tanibirumab, and Ramucirumab have been approved for the treatment of advanced and metastatic cancers. However, anti-angiogenic therapy has turned out to be more complex than originally thought. The failure of this therapeutic option calls for a reevaluation of VEGF as the major target in anti-angiogenic cancer therapy. The call for reassessment is based on two rationales: first, tumour blood vessels are abnormal, disorganized, and leaky; this not only prevents optimal drug delivery but it also promotes hypoxia and metastasis; secondly, tumour growth or regrowth might be blood vessel dependent and not angiogenesis dependent as tumour cells can acquire blood vessels via non-angiogenic mechanisms. Therefore, a critical assessment of VEGF, VEGFRs, and their inhibitors could glean newer options such as repurposing anti-VEGF drugs as vascular normalizing agents to enhance drug delivery of immune checkpoint inhibitors.

WISP2/CCN5 Suppresses Vasculogenic Mimicry through Inhibition of YAP/TAZ Signaling in Breast Cancer Cells

Simple Summary

Breast cancer is the most frequent malignancy in women worldwide. Advanced breast cancer with distant organ metastases is considered incurable with currently available therapies. The vasculogenic mimicry (VM) process is associated with an invasive and metastatic cancer phenotype and a poor prognosis for human breast cancer patients. Our aim was to study the effect of WISP2, a matricellular protein, on VM. We found that WISP2 inhibits VM through inhibition of CYR61 protein expression and YAP-TAZ signaling. Our finding may open promising candidates for blocking VM in breast cancer.

Abstract

Vasculogenic mimicry (VM) formed by aggressive tumor cells to create vascular networks connected with the endothelial cells, plays an important role in breast cancer progression. WISP2 has been considered as a tumor suppressor protein; however, the relationship between WISP2 and VM formation remains unclear. We used the in vitro tube formation assay and in vivo immunohistochemical analysis in a mouse model, and human breast tumors were used to evaluate the effect of WISP2 on VM formation. Here we report that WISP2 acts as a potent inhibitor of VM formation in breast cancer. Enforced expression of WISP2 decreased network formation while knockdown of WISP2 increased VM. Mechanistically, WISP2 increased retention of oncogenic activators YAP/TAZ in cytoplasm, leading to decreased expression of the angiogenic factor CYR61. Studies using an in vivo mouse model and human breast tumors confirmed the in vitro cell lines data. In conclusion, our results indicate that WISP2 may play a critical role in VM and highlight the critical role of WISP2 as a tumor suppressor.

Angiogenesis in patient-derived xenografts of odontogenic myxoma

Previously, by employing 3D organotypic tissue culture and patient-derived xenograft (PDX) model, oral myxoma response to a MAPK/MEK inhibitor was observed. Gross examination of the tumour fragments obtained after 55 days of PDX grafting revealed increased capsule vascularization. Microscopic analyses showed blood capillaries intermixed with myxoma cells, but the origin of these capillaries, from mice or humans, was not established. This study aimed to investigate whether the endothelial cells observed in the myxoma PDX model are derived from the mouse or from the primary human tumour. Immunohistochemistry was performed on five tumour fragments from the PDX of myxoma after 55 days of implantation in mice. Immunopositivity for antibodies against human (HLA-ABC) and mouse (H2 Db/H2-D1) major histocompatibility complex class I (MHCI) was assessed in the endothelial cells. The endothelial cells in the PDX fragments revealed a membrane staining for the human MHCI protein in the PDX tumour and adjacent connective tissue capsule, indicating that capillaries were derived from the human tumour fragment. Considering the probable human origin of the endothelial cells from capillary blood vessels in the myxoma PDX, we conclude that this PDX model is an interesting model to study myxoma angiogenesis.

Transmembrane Protein TMEM230, a Target of Glioblastoma Therapy

Glioblastomas (GBM) are the most aggressive tumors originating in the brain. Histopathologic features include circuitous, disorganized, and highly permeable blood vessels with intermittent blood flow. These features contribute to the inability to direct therapeutic agents to tumor cells. Known targets for anti-angiogenic therapies provide minimal or no effect in overall survival of 12–15 months following diagnosis. Identification of novel targets therefore remains an important goal for effective treatment of highly vascularized tumors such as GBM. We previously demonstrated in zebrafish that a balanced level of expression of the transmembrane protein TMEM230/C20ORF30 was required to maintain normal blood vessel structural integrity and promote proper vessel network formation. To investigate whether TMEM230 has a role in the pathogenesis of GBM, we analyzed its prognostic value in patient tumor gene expression datasets and performed cell functional analysis. TMEM230 was found necessary for growth of U87-MG cells, a model of human GBM. Downregulation of TMEM230 resulted in loss of U87 migration, substratum adhesion, and re-passaging capacity. Conditioned media from U87 expressing endogenous TMEM230 induced sprouting and tubule-like structure formation of HUVECs. Moreover, TMEM230 promoted vascular mimicry-like behavior of U87 cells. Gene expression analysis of 702 patients identified that TMEM230 expression levels distinguished high from low grade gliomas. Transcriptomic analysis of patients with gliomas revealed molecular pathways consistent with properties observed in U87 cell assays. Within low grade gliomas, elevated TMEM230 expression levels correlated with reduced overall survival independent from tumor subtype. Highest level of TMEM230 correlated with glioblastoma and ATP-dependent microtubule kinesin motor activity, providing a direction for future therapeutic intervention. Our studies support that TMEM230 has both glial tumor and endothelial cell intracellular and extracellular functions. Elevated levels of TMEM230 promote glial tumor cell migration, extracellular scaffold remodeling, and hypervascularization and abnormal formation of blood vessels. Downregulation of TMEM230 expression may inhibit both low grade glioma and glioblastoma tumor progression and promote normalization of abnormally formed blood vessels. TMEM230 therefore is both a promising anticancer and antiangiogenic therapeutic target for inhibiting GBM tumor cells and tumor-driven angiogenesis.

Effect of Auraptene on angiogenesis in Xenograft model of breast cancer

OBJECTIVES

Angiogenesis is the most important challenge in breast cancer treatment. Recently, scientists become interesting in rare natural products and intensive researches was performed to identify their pharmacological profile. Auraptene shows helpful effects such as cancer chemo-preventive, anti-inflammatory, anti-oxidant, immuno-modulatory. In this regard, we investigated the anti-angiogenesis effect of Auraptene in in-vitro and in-vivo model of breast cancer.

METHODS

In this study, 4T, MDA-MB-231 and HUVEC cell lines were used. The proliferation study was done by MTT assay. For tube formation assay, 250 matrigel, 1 × 10⁴ HUVEC treated with Auraptene, 20 ng/mL EGF, 20 ng/mL bFGF and 20 ng/mL VEGF were used. Gene expression of important gene related to angiogenesis in animal model of breast cancer was investigated by Real-time PCR. Protein expression of VCAM-1 and TNFR-1 gene related to angiogenesis in animal model of breast cancer was investigated by western-blot.

RESULTS

Auraptene treatment led to reduction in cell viability of MDA-MB-231 in a concentration-dependent manner. Also, we observed change in the number of tubes or branches formed by cells incubated with 40 and 80 μM Auraptene. Auraptene effect the gene expression of important gene related to angiogenesis (VEGF, VEGFR2, COX2, IFNɣ). Moreover, the western blot data exhibited that Auraptene effect the protein expression of VCAM-1 and TNFR-1.

CONCLUSIONS

Overall, this study shows that Auraptene significantly suppressed angiogenesis via down-regulation of VEGF, VEGFR2, VCAM-1, TNFR-1, COX-2 and up-regulation of IFNγ.

Recapitulating the Angiogenic Switch in a Hydrogel-Based 3D In Vitro Tumor-Stroma Model

To ensure nutrient and oxygen supply, tumors beyond a size of 1–2 mm³ need a connection to the vascular system. Thus, tumor cells modify physiological tissue homeostasis by secreting inflammatory and angiogenic cytokines. This leads to the activation of the tumor microenvironment and the turning of the angiogenic switch, resulting in tumor vascularization and growth. To inhibit tumor growth by developing efficient anti-angiogenic therapies, an in depth understanding of the molecular mechanism initiating angiogenesis is essential. Yet so far, predominantly 2D cell cultures or animal models have been used to clarify the interactions within the tumor stroma, resulting in poor transferability of the data obtained to the in vivo situation. Consequently, there is an abundant need for complex, humanized, 3D models in vitro. We established a dextran-hydrogel-based 3D organotypic in vitro model containing microtumor spheroids, macrophages, neutrophils, fibroblasts and endothelial cells, allowing for the analysis of tumor–stroma interactions in a controlled and modifiable environment. During the cultivation period of 21 days, the microtumor spheroids in the model grew in size and endothelial cells formed elongated tubular structures resembling capillary vessels, that appeared to extend towards the tumor spheroids. The tubular structures exhibited complex bifurcations and expanded without adding external angiogenic factors such as VEGF to the culture. To allow high-throughput screening of therapeutic candidates, the 3D cell culture model was successfully miniaturized to a 96-well format, while still maintaining the same level of tumor spheroid growth and vascular sprouting. The quantification of VEGF in the conditioned medium of these cultures showed a continuous increase during the cultivation period, suggesting the contribution of endogenous VEGF to the induction of the angiogenic switch and vascular sprouting. Thus, this model is highly suitable as a testing platform for novel anticancer therapeutics targeting the tumor as well as the vascular compartment.

Target-Based Radiosensitization Strategies: Concepts and Companion Animal Model Outlook

External beam radiotherapy is indicated in approximately 50-60% of human cancer patients. The prescribed dose of ionizing radiation that can be delivered to a tumor is determined by the sensitivity of the normal surrounding tissues. Despite dose intensification provided by highly conformal radiotherapy, durable locoregional tumor control remains a clinical barrier for recalcitrant tumor histologies, and contributes to cancer morbidity and mortality. Development of target-based radiosensitization strategies that selectively sensitizes tumor tissue to ionizing radiation is expected to improve radiotherapy efficacy. While exploration of radiosensitization strategies has vastly expanded with technological advances permitting the precise and conformal delivery of radiation, maximal clinical benefit derived from radiotherapy will require complementary discoveries that exploit molecularly-based vulnerabilities of tumor cells, as well as the assessment of investigational radiotherapy strategies in animal models that faithfully recapitulate radiobiologic responses of human cancers. To address these requirements, the purpose of this review is to underscore current and emerging concepts of molecularly targeted radiosensitizing strategies and highlight the utility of companion animal models for improving the predictive value of radiotherapy investigations.

Effect of Apatinib plus melatonin on vasculogenic mimicry formation by cancer stem cells from breast cancer cell line

BACKGROUND AND AIM

Vasculogenic mimicry (VM) is one of the most important causes of breast cancer metastasis and resistance against drugs. The cancer stem cells (CSCs) are known as essential factors for VM formation. In this study, the effects of melatonin, Apatinib, and a combination of Apatinib/melatonin on VM formation were investigated by breast CSCs from breast cancer cell line.

MATERIALS AND METHODS

The percentage of CSCs was determined in two breast cancer cell lines (MCF-7 and MDA-MB-231) by flow cytometry. The effects of Apatinib, melatonin, and a combination of Apatinib/melatonin were evaluated on proliferation and viability, migration and invasion, apoptosis, and VM formation in MDA-MB-231 cells. Moreover, expression levels of the involved proteins in cancer cell proliferation and viability, CSCs, migration and invasion, and VM formation were evaluated by real-time polymerase chain reaction (RT-PCR) and western blotting methods.

RESULTS

Results of the present study showed that melatonin and Apatinib reduced survival rate of CSCs in a dose- and time-dependent manner. Apatinib, melatonin, and a combination of Apatinib/melatonin inhibited proliferation of breast CSCs (P ≤ 0.001). Formation of VM was decreased in the MDA-MB-231 cancer cell line treated with Apatinib and combination of Apatinib/melatonin. Apatinib and combination of Apatinib/melatonin reduced invasion of breast CSCs (P ≤ 0.0001). Expression of vascular endothelial VE-cadherin, ephrinA2 receptor (EPHA2), p-PI3K/phosphoinositide-3 kinase (PI3K) and phospho-AKT (p-AKT)/AKT ratios was decreased under the influence of Apatinib and a combination of Apatinib/melatonin (P ≤ 0.01).

CONCLUSION

Apatinib or a combination of Apatinib/melatonin may be used to manage patients with breast cancer. However, further studies are needed to identify anti-cancer mechanisms of melatonin and Apatinib for better management of the patients with breast cancer.

The emerging roles of circular RNAs in vessel co-option and vasculogenic mimicry: clinical insights for anti-angiogenic therapy in cancers

Unexpected resistance to anti-angiogenic treatment prompted the investigation of non-angiogenic tumor processes. Vessel co-option (VC) and vasculogenic mimicry (VM) are recognized as primary non-angiogenic mechanisms. In VC, cancer cells utilize pre-existing blood vessels for support, whereas in VM, cancer cells channel and provide blood flow to rapidly growing tumors. Both processes have been implicated in the development of tumor and resistance to anti-angiogenic drugs in many tumor types. The morphology, but rare molecular alterations have been investigated in VC and VM. There is a pressing need to better understand the underlying cellular and molecular mechanisms. Here, we review the emerging circular RNA (circRNA)-mediated regulation of non-angiogenic processes, VC and VM.

Psoralidin exerts anti-tumor, anti-angiogenic, and immunostimulatory activities in 4T1 tumor-bearing balb/c mice

BACKGROUND

Psoralidin as a compound of the Psoralea corylifolia seeds exhibited several anti-cancer potentials in various cancers.

MATERIALS AND METHODS

In this study, 4T1 tumor-bearing Balb/c mice were treated by intraperitoneal administration of Psoralidin, and Paraffin, as a control group to investigate anti-tumor, anti-angiogenic, and immunostimulatory activities in breast cancer. Body weight and tumor volume measurement were performed. Hematoxylin and Eosin (H&E) staining as well as immunohistochemistry for Ki-67, CD31 and VEGF markers were conducted. In addition, ELISA assay was performed for evaluating the serum level of IFN-γ and IL-4. Moreover, real time assay was performed to evaluate the expression of angiogenesis and immunostimulatory related genes.

RESULTS

There were no significant changes in the body weight of all animal groups. The anti-cancer effects of Psoralidin were significantly observed after 24 days of the last treatment, confirmed by smaller tumor volume and also H&E staining. The expression level of Ki-67, CD31 and VEGF were significantly decreased in tumor tissues of the Psoralidin-treated group in comparison with Paraffin-treated group. Moreover, there was a significant reduction in the serum level of IL-4 in tumor-bearing mice after Psoralidin treatment while the serum level of IFN-γ was significantly augmented in all groups. Moreover, the reduction in expression of VEGF-a and IL-1β was observed. Interestingly Psoralidin treatment led to expression increase of FOXp3.

CONCLUSIONS

Psoralidin shows the anti-cancer potential in an animal model of breast cancer; however, further studies are recommended to elucidate its mechanisms of action.

Cooperation Between Cancer and Fibroblasts in Vascular Mimicry and N2-Type Neutrophil Recruitment via Notch2-Jagged1 Interaction in Lung Cancer

Background

Angiogenesis is required for tumor development and metastasis, which is a major part in a pro-tumor microenvironment. Vascular mimicry (VM) is a process in which cancer cells, rather than endothelia, create an alternative perfusion system to support the tumor progression.

Objectives

To validate the role of VM and to develop a strategy to inhibit angiogenesis in lung cancer.

Methods

In this study, we utilized lung cancer samples to verify the existence of VM and conducted several experimental methods to elucidate the molecular pathways.

Results

H1299 and CL1-0 lung cancer cells were unable to form capillary-like structures. VM formation was induced by cancer-associated fibroblast (CAFs) in both in vitro and in vivo experiments. Notch2–Jagged1 cell–cell contact between cancer cells and CAFs contributes to the formation of VM networks, supported by Notch intracellular domain (NICD) 2 nuclear translocation and N2ICD target gene upregulated in lung cancer cells mixed with CAFs. The polarization of tumor-promoting N2-type neutrophil was increased by VM networks consisting of CAF and cancer cells. The intravasation of cancer cells and N2-type neutrophils were increased because of the loose junctions of VM. Disruption of cancer cell–CAF connections by a γ‐secretase inhibitor enforced the anticancer effect of anti‐vascular endothelial growth factor antibodies in a mouse model.

Conclusion

This study provides the first evidence that CAFs induce lung cancer to create vascular-like networks. These findings suggest a therapeutic opportunity for improving antiangiogenesis therapy in lung cancer.

Potential Therapeutic Effects of Melatonin Mediate via miRNAs in Cancer

miRNAs are evolutionarily conserved non-coding ribonucleic acids with a length of between 19 and 25 nucleotides. Because of their ability to regulate gene expression, miRNAs have an important function in the controlling of various biological processes, such as cell cycle, differentiation, proliferation, and apoptosis. Owing to the long-standing regulative potential of miRNAs in tumor-suppressive pathways, scholars have recently paid closer attention to the expression profile of miRNAs in various types of cancer. Melatonin, an indolic compound secreted from pineal gland and some peripheral tissues, has been considered as an effective anti-tumor hormone in a wide spectrum of cancers. Furthermore, it induces apoptosis, inhibits tumor metastasis and invasion, and also angiogenesis. A growing body of evidence indicates the effects of melatonin on miRNAs expression in broad spectrum of diseases, including cancer. Due to the long-term effects of the regulation of miRNAs expression, melatonin could be a promising therapeutic factor in the treatment of cancers via the regulation of miRNAs. Therefore, in this review, we will discuss the effects of melatonin on miRNAs expression in various types of cancers.

Antitumor effects of Auraptene in 4T1 tumor-bearing Balb/c mice

OBJECTIVES

Breast cancer is a common malignant tumor in women with limited treatment options and multiple side effects. Today, the anti-cancer properties of natural compounds have attracted widespread attention from researchers worldwide.

METHODS

In this study, we treated 4T1 tumor-bearing Balb/c mice with intraperitoneal injection of Auraptene, paraffin oil, and saline as two control groups. Body weight and tumor volume were measured before and after treatment. Hematoxylin and eosin (H & E) staining and immunohistochemistry of Ki-67 were used as markers of proliferation. In addition, ELISA assays were performed to assess serum IFN-γ and IL-4 levels.

RESULTS

There was no significant change in body weight in all animal groups before and after treatment. 10 days after the last treatment, Auraptene showed its anti-cancer effect, which was confirmed by the smaller tumor volume and H & E staining. In addition, Ki-67 expression levels were significantly reduced in tumor samples from the Auraptene-treated group compared to the paraffin oil and saline-treated groups. In addition, in tumor-bearing and normal mice receiving Auraptene treatment, IL-4 serum production levels were reduced, while serum levels of IFN-γ were significantly up-regulated in tumor-bearing mice after Auraptene treatment.

CONCLUSIONS

In the case of inhibition of tumor volume and Ki-67 proliferation markers, Auraptene can effectively inhibit tumor growth in breast cancer animal models. In addition, it might increases Th1 and CD8 + T cell responses after reducing IL-4 serum levels and IFN-γ upregulation, respectively. However, further research is needed to clarify its mechanism of action.

Decoding Melanoma Development and Progression: Identification of Therapeutic Vulnerabilities

Melanoma, a cancer of the skin, arises from transformed melanocytes. Melanoma has the highest mutational burden of any cancer partially attributed to UV induced DNA damage. Localized melanoma is “curable” by surgical resection and is followed by radiation therapy to eliminate any remaining cancer cells. Targeted therapies against components of the MAPK signaling cascade and immunotherapies which block immune checkpoints have shown remarkable clinical responses, however with the onset of resistance in most patients, and, disease relapse, these patients eventually become refractory to treatments. Although great advances have been made in our understanding of the metastatic process in cancers including melanoma, therapy failure suggests that much remains to be learned and understood about the multi-step process of tumor metastasis. In this review we provide an overview of melanocytic transformation into malignant melanoma and key molecular events that occur during this evolution. A better understanding of the complex processes entailing cancer cell dissemination will improve the mechanistic driven design of therapies that target specific steps involved in cancer metastasis to improve clinical response rates and overall survival in all cancer patients.

The potential therapeutic effects of melatonin on breast cancer: An invasion and metastasis inhibitor

Breast cancer is the most common cancer among women and its metastasis which generally observed at the last stage is the major cause of breast cancer-related death. Therefore, the agents that have the potential to prevent metastatic and invasive nature of breast cancer can open up new therapeutic strategies. Melatonin, a major hormone of pineal gland, is a powerful anti-cancer agent. There are growing evidence regarding the protective effect of melatonin against cancer invasion and metastasis. The anti-metastatic feature of melatonin accompanies with suppression of tumor proliferation, induction of tumor apoptosis, regulation of the cell cycle, modulating angiogenesis, impediment of invasion, and induction of cancer cells sensitivity to the chemotherapy agents. More recently, anti-metastatic effect of melatonin through affecting cancer stem cells and vascular mimicry has been identified. Thus, the aim of this review is to discuss the potential therapeutic effect of melatonin on breast cancer via modulating the cells invasion and metastasis.

Inhibitory effect of melatonin on hypoxia-induced vasculogenic mimicry via suppressing epithelial-mesenchymal transition (EMT) in breast cancer stem cells

Vasculogenic mimicry (VM) play an important role in breast cancer metastasis and anti- angiogenic drugs resistance. Hypoxia, the epithelial-mesenchymal transition (EMT), and cancer stem cells (CSCs) are known as essential factors for VM formation. Also, melatonin is an amino acid-derived hormone with many anti-tumor effects. Despite the antitumor effects of melatonin, its effect on VM formation in breast cancer has not been considered yet, so we investigated the effect of melatonin on VM formation through EMT process under hypoxia conditions in breast CSCs. The CSCs percentage and VM formation were determined in MCF-7 and MDA-MB-231, respectively. Also, analysis of HIF-1α expression under hypoxia in MDA-MB-231 and MCF-7 cell lines was performed using Western blot. The effect of melatonin on the VM formation, invasion, and migration was also investigated. Moreover, the effect of melatonin on the expression EMT markers was evaluated. CD44⁺ CD24^-phenotype as CSCs marker in MDA-MB-231 cell line, was 80.8%, while it was 11.1% in MCF-7 cell line. HIF-1α expression was up-regulated in the VM-positive breast cancer cell line MDA-MB-231, and consequently, affected the expression of the EMT markers E-cadherin, vimentin, snail, and MMP9. Melatonin had significant effect on EMT and formations of VM in breast CSCs. Melatonin could prevent the formation of VM by affecting the important molecules involved in the formation of VM structures and the EMT. Moreover, our data clearly showed that, melatonin represents molecule with significant anti-cancer activities that may potentially optimize the management of breast cancer through the overcoming drug resistance in anti-angiogenic drugs.