Vascular mimicry in cultured head and neck tumour cell lines

Non-targeted Metabolomics Reveals the Potential Role of MFSD8 in Metabolism in Human Endothelial Cells

The major facilitator superfamily domain containing 8 (MFSD8) belongs to an orphan transporter protein expressed in a wide range of tissues. Nevertheless, the specific role of MFSD8 in human health and disease remains unknown. This study aimed to evaluate the role of MFSD8 protein on metabolic function using untargeted metabolomics analysis in human umbilical vein endothelial cells (HUVECs). HUVECs overexpressing MFSD8 were subjected to metabolomics analysis to evaluate changes in endogenous small molecules using LC-MS/MS analysis. In the positive scan mode, 634 metabolites from 1583 compounds were identified. In the negative scan mode, 169 metabolites from 405 compounds were identified. According to the established criteria for identifying differential metabolites, 96 metabolites exhibited significant differences between the MFSD8 and Vector groups. Among them, 62 metabolites were found to be up-regulated, whereas 34 metabolites were classified as down-regulated. Bioinformatics pipeline analysis revealed three common metabolic pathways, including arginine biosynthesis, beta-alanine metabolism, and pyrimidine metabolism, were found under the positive and negative scan modes. The semi-quantitative analysis was conducted on the differential metabolites, revealing that overexpression of MFSD8 resulted in increased levels of L-citrulline, L-aspartic acid, ornithine, N-acetyl-l-aspartic acid, L-histidine, beta-alanine metabolites and exhibited decreased levels of cytidine. The findings of our study indicated that MFSD8 had the most significant role in arginine biosynthesis, beta-alanine metabolism, and pyrimidine metabolism pathways within endothelial cells. The metabolomics data provide new insights into studying potential features of MFSD8 protein in the future.

PD-L1 knockdown suppresses vasculogenic mimicry of non-small cell lung cancer by modulating ZEB1-triggered EMT

BACKGROUND

PD-L1 overexpression is commonly observed in various malignancies and is strongly correlated with poor prognoses for cancer patients. Moreover, PD-L1 has been shown to play a significant role in promoting angiogenesis and epithelial-mesenchymal transition (EMT) processes across different cancer types.

METHODS

The relationship between PD-L1 and vasculogenic mimicry as well as epithelial-mesenchymal transition (EMT) was explored by bioinformatics approach and immunohistochemistry. The functions of PD-L1 in regulating the expression of ZEB1 and the EMT process were assessed by Western blotting and q-PCR assays. The impact of PD-L1 on the migratory and proliferative capabilities of A549 and H1299 cells was evaluated through wound healing, cell invasion, and CCK8 assays following siRNA-mediated PD-L1 knockdown. Tube formation assay was utilized to evaluate the presence of VM structures.

RESULTS

In this study, increased PD-L1 expression was observed in A549 and H1299 cells compared to normal lung epithelial cells. Immunohistochemical analysis revealed a higher prevalence of VM structures in the PD-L1-positive group compared to the PD-L1-negative group. Additionally, high PD-L1 expression was also found to be significantly associated with advanced TNM stage and increased metastasis. Following PD-L1 knockdown, NSCLC cells exhibited a notable reduction in their ability to form tube-like structures. Moreover, the levels of key EMT and VM-related markers, including N-cadherin, MMP9, VE-cadherin, and VEGFA, were significantly decreased, while E-cadherin expression was upregulated. In addition, the migration and proliferation capacities of both cell lines were significantly inhibited after PD-L1 or ZEB1 knockdown.

CONCLUSIONS

Knockdown PD-L1 can inhibit ZEB1-mediated EMT, thereby hindering the formation of VM in NSCLC.

Acidosis promotes the metastatic colonization of lung cancer via remodeling of the extracellular matrix and vasculogenic mimicry

Acidosis is a hallmark of the tumor microenvironment caused by the metabolic switch from glucose oxidative phosphorylation to glycolysis. It has been associated with tumor growth and progression; however, the precise mechanism governing how acidosis promotes metastatic dissemination has yet to be elucidated. In the present study, a long‑term acidosis model was established using patient‑derived lung cancer cells, to identify critical components of metastatic colonization via transcriptome profiling combined with both in vitro and in vivo functional assays, and association analysis using clinical samples. Xenograft inoculates of 1 or 10 acidotic cells mimicking circulating tumor cell clusters were shown to exhibit increased tumor incidence compared with their physiological pH counterparts. Transcriptomics revealed that profound remodeling of the extracellular matrix (ECM) occurred in the acidotic cells, including upregulation of the integrin subunit α‑4 (ITGA4) gene. In clinical lung cancer, ITGA4 expression was found to be upregulated in primary tumors with metastatic capability, and this trait was retained in the corresponding secondary tumors. Expression of ITGA4 was markedly upregulated around the vasculogenic mimicry structures of the acidotic tumors, while acidotic cells exhibited a higher ability of vasculogenic mimicry in vitro. Acidosis was also found to induce the enrichment of side population cells, suggesting an enhanced resistance to noxious attacks of the tumor microenvironment. Taken together, these results demonstrated that acidosis actively contributed to tumor metastatic colonization, and novel mechanistic insights into the therapeutic management and prognosis of lung cancer were discussed.

Vasculogenic Mimicry in Head and Neck Squamous Cell Carcinoma-Time to Take Notice

Head and neck squamous cell carcinoma (HNSCC) is a group of common cancers characterized by a swift growth pattern, early metastasis, and dismal 5-year survival rates. Despite the recent advances in cancer management, the multimodality approach is not effective in eradicating HNSCC. Moreover, the clinical response to the antiangiogenic therapy remains considerably limited in HNSCC patients, suggesting that tumor perfusion can take place through other non-angiogenic pathways. Tumor cell-induced angiogenesis is one of the main hallmarks of cancer. However, at the end of the previous millennium, a new paradigm of tumor cell-associated neovascularization has been reported in human melanoma cells. This new phenomenon, which was named "vasculogenic mimicry" or "vascular mimicry" (VM), describes the ability of aggressively growing tumor cells to form perfusable, matrix-rich, vessel-like networks in 3-dimensional matrices in vitro. Similar matrix-rich VM networks were also identified in tissue samples obtained from cancer patients. To date, myriad studies have reported intriguing features of VM in a wide variety of cancers including HNSCC. We aim in this mini-review to summarize the current evidence regarding the phenomenon of VM in HNSCC-from the available detection protocols and potentially involved mechanisms, to its prognostic value and the present limitations.

Vasculogenic Mimicry-An Overview

Vasculogenic mimicry (VM), a tumor microcirculation model found in melanoma in the last 20 years, is a vascular channel-like structure composed of tumor cells, but without endothelial cells, that stains positive for periodic acid-Schiff (PAS) and negative staining for CD31. VM provides, to the highly aggressive malignant tumor cells, adequate oxygen and nutrient supply for tumor growth and subsequent metastasis process and its presence are related to poor prognosis in patients. VM is independent of endothelial cells, which may partly explain why angiogenesis drug inhibitors have not achieved the expected success for cancer treatment.

The effect of interleukin-17F on vasculogenic mimicry in oral tongue squamous cell carcinoma

Oral tongue squamous cell carcinoma (OTSCC) is one of the most common cancers worldwide and is characterized by early metastasis and poor prognosis. Recently, we reported that extracellular interleukin-17F (IL-17F) correlates with better disease-specific survival in OTSCC patients and has promising anticancer effects in vitro. Vasculogenic mimicry (VM) is the formation of an alternative vasculogenic system by aggressive tumor cells, which is implicated in treatment failure and poor survival of cancer patients. We sought to confirm the formation of VM in OTSCC and to investigate the effect of IL-17F on VM formation. Here, we showed that highly invasive OTSCC cells (HSC-3 and SAS) form tube-like VM on Matrigel similar to those formed by human umbilical vein endothelial cells. Interestingly, the less invasive cells (SCC-25) did not form any VM structures. Droplet-digital PCR, FACS, and immunofluorescence staining revealed the presence of CD31 mRNA and protein in OTSCC cells. Additionally, in a mouse orthotopic model, HSC-3 cells expressed VE-cadherin (CD144) but lacked Von Willebrand Factor. We identified different patterns of VM structures in patient samples and in an orthotopic OTSCC mouse model. Similar to the effect produced by the antiangiogenic drug sorafenib, IL-17F inhibited the formation of VM structures in vitro by HSC-3 and reduced almost all VM-related parameters. In conclusion, our findings indicate the presence of VM in OTSCC and the antitumorigenic effect of IL-17F through its effect on the VM. Therefore, targeting IL-17F or its regulatory pathways may lead to promising therapeutic strategies in patients with OTSCC.

Tumor angiogenesis: causes, consequences, challenges and opportunities

Tumor vascularization occurs through several distinct biological processes, which not only vary between tumor type and anatomic location, but also occur simultaneously within the same cancer tissue. These processes are orchestrated by a range of secreted factors and signaling pathways and can involve participation of non-endothelial cells, such as progenitors or cancer stem cells. Anti-angiogenic therapies using either antibodies or tyrosine kinase inhibitors have been approved to treat several types of cancer. However, the benefit of treatment has so far been modest, some patients not responding at all and others acquiring resistance. It is becoming increasingly clear that blocking tumors from accessing the circulation is not an easy task to accomplish. Tumor vessel functionality and gene expression often differ vastly when comparing different cancer subtypes, and vessel phenotype can be markedly heterogeneous within a single tumor. Here, we summarize the current understanding of cellular and molecular mechanisms involved in tumor angiogenesis and discuss challenges and opportunities associated with vascular targeting.

Evaluation of the Expression of Matrix Metalloproteinase-1 of Laryngeal Squamous Cell Carcinoma by Ultrasound Molecular Imaging

Purpose: The aims of this study were to evaluate the expression of matrix metalloproteinase-1 (MMP-1) on laryngeal squamous cell carcinoma (LSCC) and improve the early diagnosis rate via ultrasound molecular imaging (USMI).

Methods: The microsized MMP-1-targeted microbubbles (MB_MMP-1) and the control MBs (MB_IgG) based on perfluorocarbon-filled lipid-shelled MBs were constructed and characterized. The in vitro binding experiment was performed with human epidermoid laryngeal cancer cells (HEp-2) and tested the binding efficiency of MB_MMP-1 and MB_IgG. In the in vivo study, the LSCC model was established in 10 mice. The MB_MMP-1 and MB_IgG were randomly injected into tumor-bearing mice via the tail vein at Day 7, Day 12, and Day 17 to dynamically evaluate the differential targeted enhancement (dTE) signals via USMI. Subsequent immunofluorescence analysis was used for confirmation of MMP-1 expression.

Result: The effective adhesion rate of MB_MMP-1 and MB_IgG to HEp-2 was 298.42 ± 16.57 versus 12.38 ± 3.26 bubbles/per field in vitro experiment, which shows a significant difference (P < 0.01). The in vivo ultrasound molecular imaging (USMI) results demonstrated that dTE signal intensity from MB_MMP-1 was significantly higher than that from the MB_IgG at Day 7, Day 12, and Day 17 (Day 7, 41.21 ± 15.00 versus 2.25 ± 0.6 a.u., P < 0.05; Day 12, 124.64 ± 5.19 versus 11.13 ± 1.13 a.u., P < 0. 05; Day 17, 332.01 ± 64.88 versus 42.99 ± 11.9 a.u., P < 0.01). Moreover, immunofluorescence analysis further confirmed the expression of MMP-1 in LSCC with a gradual increase with the tumor growth.

Conclusion: MB_MMP-1 could be a potential probe that can be used in the early diagnosis of LSCC by USMI.

Overview of advances in vasculogenic mimicry - a potential target for tumor therapy

Vasculogenic mimicry (VM) describes the process utilized by highly aggressive cancer cells to generate vascular-like structures without the presence of endothelial cells. VM has been vividly described in various tumors and participates in cancer progression dissemination and metastasis. Diverse molecular mechanisms and signaling pathways are involved in VM formation. Furthermore, the patterning characteristics of VM, detected with molecular imaging, are being investigated for use as a tool to aid clinical practice. This review explores the most recent studies investigating the role of VM in tumor induction. Indeed, the recognition of these advances will increasingly affect the development of novel therapeutic target strategies for VM in human cancer.

Phosphorylation of STAT3 Promotes Vasculogenic Mimicry by Inducing Epithelial-to-Mesenchymal Transition in Colorectal Cancer

Vasculogenic mimicry refers to the process by which highly invasive cancer cells mimic endothelial cells by forming blood channels. Vasculogenic mimicry is important for the invasion and metastasis of tumor cells in colorectal cancer. STAT3 was initially identified as a mediator of the inflammation-associated acute phase response. The phosphorylation of Signal Transducers and Activators of Transcription 3 (p-STAT3) is closely related to tumor invasion and migration. We analyzed the relationship between p-STAT3 and vasculogenic mimicry formation in 65 human colorectal cancer samples, and the results showed that the expression of p-STAT3 is significantly correlated with vasculogenic mimicry, tumor metastasis, Tumor, Lymph Node and Metastasis Stage (TNM Stage), and poor prognosis. It is known that interleukin 6 can induce the phosphorylation of STAT3. We found that using interleukin 6 to induce p-STAT3 activation in colorectal cancer cell lines can result in vasculogenic mimicry and using AG490 to suppress p-STAT3 activation restrained vasculogenic mimicry. Furthermore, the state of p-STAT3 activation can affect epithelial-to-mesenchymal transition. By immunofluorescence double staining, we discovered that p-STAT3 expression is more directly correlated with the epithelial-to-mesenchymal transition marker vimentin than with the vasculogenic mimicry-related protein VE-cadherin. These data show that activated p-STAT3 upregulates epithelial-to-mesenchymal transition–related proteins and promotes vasculogenic mimicry.

Loss of miR-449a-caused PrLZ overexpression promotes prostate cancer metastasis

Distant metastasis is the worst prognostic factor for PCa patients. It has been reported that miR-449a enhances radiosensitivity of prostate cancer cells, but the function of miR449a in metastasis of prostate cancer is mainly unknown. In the present study, we strove to investigate the function and diagnostic value of miR-449a in metastasis of prostate cancer. qRT-PCR was used to quantify the expression of miR449a and PrLZ in PCa cell lines and tissues. we found that miR449a expression was decreased in PCa cell lines. Moreover, miR‑449a was downregulated in PCa tissues, especially in primary lesion tissues of metastatic PCa patients. CCK8, FACS, transwell and tube formation assay were performed to assess growth and metastasis of PCa cells in vitro. Lentivirus mediated miR-449a overexpression suppressed proliferation of LNcap and PC-3, and miR-449a also significantly inhibited invasion and angiogenesis ability of LNcap and PC-3. IHC showed that PrLZ was upregulated in PCa tissues. Luciferase assay and western blotting verified that miR-449a targeted PrLZ expression. Moreover, PrLZ shRNA also significantly suppressed proliferation and metastasis of LNcap and PC-3. In addition, western blotting revealed that miR-449a overexpression and PrLZ shRNA all remarkably inhibited the stemness features in LNcap and PC-3. Furthermore, BALB/c nude mouse subcutaneous xenograft model was uesd to verify the function of miR-449a and PrLZ. Our results showed that miR-449a and PrLZ shRNA significantly suppressed PC-3 tumorigenesis and metastasis in vivo. Our studies suggested that miR-449a decreased in malignant process of PCa and was accompanied by excess expression of PrLZ. The loss of miR-449a caused PrLZ overexpression regulated prostate cancer progression and metastasis via regulating the stemness features of prostate cancer cells. The diagnostic value of miR-449a as a distant metastasis predictor of PCa needs further investigation.

The relationship between vasculogenic mimicry and epithelial-mesenchymal transitions

Vasculogenic mimicry (VM) is a vascular‐like structure which can mimic the embryonic vascular network pattern to nourish the tumour tissue. As a unique perfusion way, VM is correlated with tumour progression, invasion, metastasis and lower 5‐year survival rate. Notably, epithelial‐mesenchymal transition (EMT) regulators and EMT‐related transcription factors are highly up‐regulated in VM‐forming tumour cells, which demonstrated that EMT may play a crucial role in VM formation. Therefore, the up‐regulation of EMT‐associated adhesion molecules and other factors can also make a contribution in VM‐forming process. Depending on these discoveries, VM and EMT can be utilized as therapeutic target strategies for anticancer therapy. The purpose of this article is to explore the advance research in the relationship of EMT and VM and their corresponding mechanisms in tumorigenesis effect.

YAP1 Regulates OCT4 Activity and SOX2 Expression to Facilitate Self-Renewal and Vascular Mimicry of Stem-Like Cells

Non-small cell lung cancer (NSCLC) is highly correlated with smoking and has very low survival rates. Multiple studies have shown that stem-like cells contribute to the genesis and progression of NSCLC. Our results show that the transcriptional coactivator yes-associated protein 1 (YAP1), which is the oncogenic component of the Hippo signaling pathway, is elevated in the stem-like cells from NSCLC and contributes to their self-renewal and ability to form angiogenic tubules. Inhibition of YAP1 by a small molecule or depletion of YAP1 by siRNAs suppressed self-renewal and vascular mimicry of stem-like cells. These effects of YAP1 were mediated through the embryonic stem cell transcription factor, Sox2. YAP1 could transcriptionally induce Sox2 through a physical interaction with Oct4; Sox2 induction occurred independent of TEAD2 transcription factor, which is the predominant mediator of YAP1 functions. The binding of Oct4 to YAP1 could be detected in cell lines as well as tumor tissues; the interaction was elevated in NSCLC samples compared to normal tissue as seen by proximity ligation assays. YAP1 bound to Oct4 through the WW domain, and a peptide corresponding to this region could disrupt the interaction. Delivery of the WW domain peptide to stem-like cells disrupted the interaction and abrogated Sox2 expression, self-renewal, and vascular mimicry. Depleting YAP1 reduced the expression of multiple epithelial-mesenchymal transition genes and prevented the growth and metastasis of tumor xenografts in mice; overexpression of Sox2 in YAP1 null cells rescued these functions. These results demonstrate a novel regulation of stem-like functions by YAP1, through the modulation of Sox2 expression.

The NC11 domain of human collagen XVI induces vasculogenic mimicry in oral squamous cell carcinoma cells

Collagen XVI, a fibril-associated collagen with interrupted triple helix (FACIT) collagen, is involved in oral squamous cell carcinoma (OSCC) and glioblastoma progression. The NC11 domain of collagen XVI has been described previously with a strong implication in physiological processes. We detected the non-collagenous (NC) 11-domain in supernatants of OSCC cells after recombinant expression of full-length collagen XVI and in sera from OSCC patients and healthy individuals. Stable expression of NC11-green fluorescent protein (GFP) fusion protein in OSCC cells initiated proliferation control and block of anchorage-independent growth. Moreover, the NC11 domain triggered the generation of tubular-like net structures on laminin-rich matrix in contrast to mock-GFP control cells and cells expressing full-length collagen XVI. Taqman® quantitative PCR and diaminobenzidine staining in 2D- and 3D cell culture revealed a significantly increased gene and protein expression of VEGFR1, VEGFR2 and uPAR in recombinant NC11-GFP-expressing cells. Specific VEGF receptor inhibition with Axitinib or fetal calf serum heat inactivation prevented formation of tubular-like net structures. Accordantly, NC11-GFP coated culture slides led to an increase of focal adhesion contact formation and the upregulation of VEGFR1 and uPAR in three different non-transfected OSCC cell lines. In summary, we suggest that the NC11 domain of collagen XVI is a potential biomarker for OSCC and triggers vasculogenic mimicry via upregulation of endothelial receptors VEGFR1, VEGFR2 and uPAR in 2D- and 3D OSCC cell culture conditions.

Pivotal role of pervasive neoplastic and stromal cells reprogramming in circulating tumor cells dissemination and metastatic colonization

Reciprocal interactions between neoplastic cells and their microenvironment are crucial events in carcinogenesis and tumor progression. Pervasive stromal reprogramming and remodeling that transform a normal to a tumorigenic microenvironment modify numerous stromal cells functions, status redox, oxidative stress, pH, ECM stiffness and energy metabolism. These environmental factors allow selection of more aggressive cancer cells that develop important adaptive strategies. Subpopulations of cancer cells acquire new properties associating plasticity, stem-like phenotype, unfolded protein response, metabolic reprogramming and autophagy, production of exosomes, survival to anoikis, invasion, immunosuppression and therapeutic resistance. Moreover, by inducing vascular transdifferentiation of cancer cells and recruiting endothelial cells and pericytes, the tumorigenic microenvironment induces development of tumor-associated vessels that allow invasive cells to gain access to the tumor vessels and to intravasate. Circulating cancer cells can survive in the blood stream by interacting with the intravascular microenvironment, extravasate through the microvasculature and interact with the metastatic microenvironment of target organs. In this review, we will focus on many recent paradigms involved in the field of tumor progression.

A new perspective of vasculogenic mimicry: EMT and cancer stem cells (Review)

Vasculogenic mimicry (VM), a new pattern of tumor microcirculation, is important for the growth and progression of tumors. Epithelial-mesenchymal transition (EMT) is pivotal in malignant tumor progression and VM formation. With increasing knowledge of cancer stem cell (CSC) phenotypes and functions, increasing evidence suggests that CSCs are involved in VM formation. Recent studies have indicated that EMT is relevant to the acquisition and maintenance of stem cell-like characteristics. Thus, in this review we discuss the correlation between CSCs, EMT and VM formation.

Inherent phenotypic plasticity facilitates progression of head and neck cancer: endotheliod characteristics enable angiogenesis and invasion

The presence of the EMT (epithelial-mesenchymal transition), EndMT (endothelial-mesenchymal transition) and VM (vasculogenic mimicry) demonstrates the multidirectional extent of phenotypic plasticity in cancers. Previous findings demonstrating the crosstalk between head and neck squamous cell carcinoma (HNSCC) and vascular endothelial growth factor (VEGF) imply that HNSCC cells share some functional commonalities with endothelial cells. Our current results reveal that cultured HNSCC cells not only possess endothelial-specific markers, but also display endotheliod functional features including low density lipoprotein uptake, formation of tube-like structures on Matrigel and growth state responsiveness to VEGF and endostatin. HNSCC cell subpopulations are also highly responsive to transforming growth factor-β1 and express its auxiliary receptor, endoglin. Furthermore, the endotheliod characteristics observed in vitro recapitulate phenotypic features observed in human HNSCC tumors. Conversely, cultured normal human oral keratinocytes and intact or ulcerated human oral epithelia do not express comparable endotheliod characteristics, which imply that assumption of endotheliod features is restricted to transformed keratinocytes. In addition, this phenotypic state reciprocity facilitates HNSCC progression by increasing production of factors that are concurrently pro-proliferative and pro-angiogenic, conserving cell energy stores by LDL internalization and enhancing cell mobility. Finally, recognition of this endotheliod phenotypic transition provides a solid rationale to evaluate the antitumorigenic potential of therapeutic agents formerly regarded as exclusively angiostatic in scope.