Isolation and characterization of vasohibin-2 as a homologue of VEGF-inducible endothelium-derived angiogenesis inhibitor vasohibin

Development of a Novel and Simple Anti-Metastatic Cancer Treatment Targeting Vasohibin-2

Vasohibin-2 (VASH2), a homologue of vasohibin-1 (VASH1), is overexpressed in various cancer cells and promotes tumor progression. We therefore regard VASH2 as a molecular target for cancer treatment. Here we applied vaccine technology to develop a therapy against VASH2. We selected two amino acid sequences of VASH2 protein; the MTG and RRR peptides, which contain possible B cell epitopes. These sequences are identical between the human and murine VASH2 proteins and distinct from those of the VASH1 protein. We conjugated these peptides with the carrier protein keyhole limpet hemocyanin, mixed with an adjuvant, and injected subcutaneously twice at a 2-week interval in mice. Both vaccines increased antibodies against the antigen peptide; however, only the MTG peptide vaccine increased antibodies that recognized the recombinant VASH2 protein. When Lewis lung cancer (LLC) cells were subcutaneously inoculated, tumors isolated from mice immunized with the MTG peptide vaccine showed a significant decrease in the expression of epithelial-to-mesenchymal transition (EMT) markers. EMT is responsible for cancer cell invasion and metastasis. When the LLC cells were injected into the tail vein, the MTG peptide vaccine inhibited lung metastasis. Moreover, the MTG peptide vaccine inhibited the metastasis of pancreatic cancer cells to the liver in an orthotopic mouse model, and there was a significant inverse correlation between the ELISA titer and metastasis inhibition. Therefore, we propose that the MTG peptide vaccine is a novel anti-metastatic cancer treatment that targets VASH2 and can be applied even in the most malignant and highly metastatic pancreatic cancer.

Novel strategy of liver cancer treatment with modified antisense oligonucleotides targeting human vasohibin-2

Vasohihibin-2 (VASH2) is a homolog of vasohibin-1 (VASH1) and is overexpressed in various cancers. Vasohihibin-2 acts on both cancer cells and cancer microenvironmental cells. Previous analyses have shown that VASH2 promotes cancer progression and abrogation of VASH2 results in significant anticancer effects. We therefore propose VASH2 to be a practical molecular target for cancer treatment. Modifications of antisense oligonucleotide (ASO) such as bridged nucleic acids (BNA)-based modification increases the specificity and stability of ASO, and are now applied to the development of a number of oligonucleotide-based drugs. Here we designed human VASH2-ASOs, selected an optimal one, and developed 2',4'-BNA-based VASH2-ASO. When systemically administered, naked 2',4'-BNA-based VASH2-ASO accumulated in the liver and showed its gene-silencing activity. We then examined the effect of 2',4'-BNA-based VASH2-ASO in liver cancers. Intraperitoneal injection of naked 2',4'-BNA-based VASH2-ASO exerted a potent antitumor effect on orthotopically inoculated human hepatocellular carcinoma cells. The same manipulation also showed potent antitumor activity on the splenic inoculation of human colon cancer cells for liver metastasis. These results provide a novel strategy for the treatment of primary as well as metastatic liver cancers by using modified ASOs targeting VASH2.

Selected commensals educate the intestinal vascular and immune system for immunocompetence

BACKGROUND

The intestinal microbiota fundamentally guides the development of a normal intestinal physiology, the education, and functioning of the mucosal immune system. The Citrobacter rodentium-carrier model in germ-free (GF) mice is suitable to study the influence of selected microbes on an otherwise blunted immune response in the absence of intestinal commensals.

RESULTS

Here, we describe that colonization of adult carrier mice with 14 selected commensal microbes (OMM¹² + MC²) was sufficient to reestablish the host immune response to enteric pathogens; this conversion was facilitated by maturation and activation of the intestinal blood vessel system and the step- and timewise stimulation of innate and adaptive immunity. While the immature colon of C. rodentium-infected GF mice did not allow sufficient extravasation of neutrophils into the gut lumen, colonization with OMM¹² + MC² commensals initiated the expansion and activation of the visceral vascular system enabling granulocyte transmigration into the gut lumen for effective pathogen elimination.

CONCLUSIONS

Consortium modeling revealed that the addition of two facultative anaerobes to the OMM¹² community was essential to further progress the intestinal development. Moreover, this study demonstrates the therapeutic value of a defined consortium to promote intestinal maturation and immunity even in adult organisms. Video Abstract.

Vasohibin-1 and -2 in pulmonary lymphangioleiomyomatosis (LAM) cells associated with angiogenic and prognostic factors

Lymphangioleiomyomatosis (LAM) is a rare pulmonary neoplasm, clinically associated with dyspnea and respiratory failure. Current therapeutic modalities do not necessarily reach satisfactory outcome and novel therapeutic approaches are currently warranted. Therefore, in this study, we focused on vasohibin-1 (VASH1) and -2 (VASH2); VASH1 terminated and VASH2 promoted angiogenesis. In addition, both VASH1/2 were reported to influence the progression of various human malignancies. We first performed hierarchical clustering analysis to attempt to classify 36 LAM cases into three different clusters according to immunoreactivity of VASH1/2 and other angiogenic and prognostic factors of LAM; VEGFR1/2/3, p-mTOR, p-S6, p-4EBP, ERα, PgR, MMP2, and MMP9. The cluster harboring higher angiogenic factors had higher VASH1/2 status. VASH1 was significantly positively correlated with VEGFR2, MMP9, and p-mTOR (p-value <0.05), and VASH2 with both angiogenic and prognostic factors including VEGFR1, PgR, MMP9, p-mTOR, p-S6, and p-4EBP (p-value <0.05). Subsequent PCR array of angiogenic genes demonstrated that high VASH1 mRNA was significantly positively associated with the status of SPHK1 and TYPM, lower EGF and EFNB2 (p-value <0.05), and high VASH2 mRNA negatively with MMP2 (p-value <0.05). VASH1 was considered to be up-regulated by activation of angiogenesis, whereas VASH2 could influence the angiogenesis and progression of LAM.

The detyrosination/re-tyrosination cycle of tubulin and its role and dysfunction in neurons and cardiomyocytes

Among the variety of post-translational modifications to which microtubules are subjected, the detyrosination/re-tyrosination cycle is specific to tubulin. It is conserved by evolution and characterized by the enzymatic removal and re-addition of a gene-encoded tyrosine residue at the C-terminus of α-tubulin. Detyrosinated tubulin can be further converted to Δ2-tubulin by the removal of an additional C-terminal glutamate residue. Detyrosinated and Δ2-tubulin are carried by stable microtubules whereas tyrosinated microtubules are present on dynamic polymers. The cycle regulates trafficking of many cargo transporting molecular motors and is linked to the microtubule dynamics via regulation of microtubule interactions with specific cellular effectors such as kinesin-13. Here, we give an historical overview of the general features discovered for the cycle. We highlight the recent progress toward structure and functioning of the enzymes that keep the levels of tyrosinated and detyrosinated tubulin in cells, the long-known tubulin tyrosine ligase and the recently discovered vasohibin-SVBP complexes. We further describe how the cycle controls microtubule functions in healthy neurons and cardiomyocytes and how deregulations of the cycle are involved in dysfunctions of these highly differentiated cells, leading to neurodegeneration and heart failure in humans.

Knockout of vasohibin-2 reduces tubulin carboxypeptidase activity and increases paclitaxel sensitivity in ovarian cancer

Vasohibin-1 (VASH1) is a VEGF-inducible endothelium-derived angiogenesis inhibitor, and vasohibin-2 (VASH2), its homolog, exhibits proangiogenic activity. VASH2 is expressed by various cancer cells and accelerates tumor angiogenesis and progression. VASH2 was recently shown to exhibit tubulin carboxypeptidase (TCP) activity related to microtubule functions. Paclitaxel (PTX), an effective chemotherapeutic agent that is widely used to treat ovarian cancer, inhibits microtubule depolymerization and may interact with VASH2. We herein established several VASH2 knockout ovarian cancer cell lines using the CRISPR/Cas9 genome editing system to examine the intracellular tubulin detyrosination status and PTX chemosensitivity. The knockout of VASH2 did not affect the proliferation or sphere-forming activity of ovarian cancer cells in vitro. A Western blot analysis of VASH2 knockout cells revealed the weak expression of detyrosinated tubulin and upregulated expression of cyclin B1. The knockout of VASH2 significantly increased chemosensitivity to PTX, but not to cisplatin in ovarian cancer cell lines. The knockout of VASH2 reduced TCP activity and increased cyclin B1 expression, resulting in increased PTX chemosensitivity in ovarian cancer cells. The inhibition of angiogenesis and regulation of microtubule activity may be achieved in ovarian cancer treatment strategies targeting VASH2.

Vasohibin 1 selectively regulates secondary sprouting and lymphangiogenesis in the zebrafish trunk

Previous studies have shown that Vasohibin 1 (Vash1) is stimulated by VEGFs in endothelial cells and that its overexpression interferes with angiogenesis in vivo Recently, Vash1 was found to mediate tubulin detyrosination, a post-translational modification that is implicated in many cell functions, such as cell division. Here, we used the zebrafish embryo to investigate the cellular and subcellular mechanisms of Vash1 on endothelial microtubules during formation of the trunk vasculature. We show that microtubules within venous-derived secondary sprouts are strongly and selectively detyrosinated in comparison with other endothelial cells, and that this difference is lost upon vash1 knockdown. Vash1 depletion in zebrafish specifically affected secondary sprouting from the posterior cardinal vein, increasing endothelial cell divisions and cell number in the sprouts. We show that altering secondary sprout numbers and structure upon Vash1 depletion leads to defective lymphatic vessel formation and ectopic lymphatic progenitor specification in the zebrafish trunk.

Peritubular Capillary Rarefaction: An Underappreciated Regulator of CKD Progression

Peritubular capillary (PTC) rarefaction is commonly detected in chronic kidney disease (CKD) such as hypertensive nephrosclerosis and diabetic nephropathy. Moreover, PTC rarefaction prominently correlates with impaired kidney function and predicts the future development of end-stage renal disease in patients with CKD. However, it is still underappreciated that PTC rarefaction is a pivotal regulator of CKD progression, primarily because the molecular mechanisms of PTC rarefaction have not been well-elucidated. In addition to the established mechanisms (reduced proangiogenic factors and increased anti-angiogenic factors), recent studies discovered significant contribution of the following elements to PTC loss: (1) prompt susceptibility of PTC to injury, (2) impaired proliferation of PTC, (3) apoptosis/senescence of PTC, and (4) pericyte detachment from PTC. Mainly based on the recent and novel findings in basic research and clinical study, this review describes the roles of the above-mentioned elements in PTC loss and focuses on the major factors regulating PTC angiogenesis, the assessment of PTC rarefaction and its surrogate markers, and an overview of the possible therapeutic agents to mitigate PTC rarefaction during CKD progression. PTC rarefaction is not only a prominent histological characteristic of CKD but also a central driving force of CKD progression.

An expanded mouse testis transcriptome and mass spectrometry defines novel proteins

The testis transcriptome is exceptionally complex. Despite its complexity, previous testis transcriptome analyses relied on a reductive method for transcript identification, thus underestimating transcriptome complexity. We describe here a more complete testis transcriptome generated by combining Tuxedo, a reductive method, and spliced-RUM, a combinatorial transcript-building approach. Forty-two percent of the expanded testis transcriptome is composed of unannotated RNAs with novel isoforms of known genes and novel genes constituting 78 and 9.8% of the newly discovered transcripts, respectively. Across tissues, novel transcripts were predominantly expressed in the testis with the exception of novel isoforms which were also highly expressed in the adult ovary. Within the testis, novel isoform expression was distributed equally across all cell types while novel genes were predominantly expressed in meiotic and post-meiotic germ cells. The majority of novel isoforms retained their protein-coding potential while most novel genes had low protein-coding potential. However, a subset of novel genes had protein-coding potentials equivalent to known protein-coding genes. Shotgun mass spectrometry of round spermatid total protein identified unique peptides from four novel genes along with seven annotated non-coding RNAs. These analyses demonstrate the testis expresses a wide range of novel transcripts that give rise to novel proteins.

Plasma vasohibin-1 and vasohibin-2 are useful biomarkers in patients with esophageal squamous cell carcinoma

BACKGROUND

Vasohibins (VASH), which are angiogenesis regulators, consist of Vasohibin-1 (VASH1) and Vasohibin-2 (VASH2). VASH1 is an angiogenesis inhibitor, while VASH2 is a proangiogenic factor. Patients with esophageal squamous cell carcinoma (ESCC) with high tumor expression levels of VASH1 and VASH2 have been reported to show a poor prognosis. The clinical significance of VASH concentrations in the blood of patients with ESCC has not yet been investigated.

METHODS

Plasma samples from 89 patients with ESCC were analyzed, and the relationships between the plasma VASH concentrations and the clinicopathological factors of the patients were evaluated. Immunohistochemical examination (IHC) of the resected tumor specimens for VASH was performed in 56 patients, and the correlation between the plasma VASH concentrations and tumor expression levels of VASH was analyzed.

RESULTS

The patient group with high plasma concentrations of VASH1 showed a higher frequency of lymph node metastasis (P = 0.01) and an invasive growth pattern (P = 0.05). Furthermore, poorly differentiated cancer occurred at a higher frequency in the patient group with high plasma concentrations of VASH2 (P < 0.01). High tumor expression levels of VASH1 were encountered more frequently in the patient group with high plasma concentrations of VASH1 (P = 0.03), and high tumor expression levels of VASH2 were encountered more frequently in the patient group with high plasma concentrations of VASH2 (P = 0.04).

CONCLUSIONS

In patients with ESCC, high plasma concentrations were associated with poor clinical outcomes for both VASH1 and VASH2. We propose that results indicate that plasma VASH1 and VASH2 are useful biomarkers in patients with ESCC.

Genetic Deletion of Vasohibin-2 Exacerbates Ischemia-Reperfusion-Induced Acute Kidney Injury

Acute kidney injury (AKI) has been increasingly recognized as a risk factor for transition to chronic kidney disease. Recent evidence suggests that endothelial damage in peritubular capillaries can accelerate the progression of renal injury. Vasohibin-2 (VASH2) is a novel proangiogenic factor that promotes tumor angiogenesis. However, the pathophysiological roles of VASH2 in kidney diseases remain unknown. In the present study, we examined the effects of VASH2 deficiency on the progression of ischemia–reperfusion (I/R) injury-induced AKI. I/R injury was induced by bilaterally clamping renal pedicles for 25 min in male wild-type (WT) and Vash2 homozygous knockout mice. Twenty-four hours later, I/R injury-induced renal dysfunction and tubular damage were more severe in VASH2-deficient mice than in WT mice, with more prominent neutrophil infiltration and peritubular capillary loss. After induction of I/R injury, VASH2 expression was markedly increased in injured renal tubules. These results suggest that VASH2 expression in renal tubular epithelial cells might be essential for alleviating I/R injury-induced AKI, probably through protecting peritubular capillaries and preventing inflammatory infiltration.

A review on vasohibin and ocular neovascularization

Ischemic and neovascular disease is one of the most difficult ocular diseases to deal with nowadays. Redundancy, poor visual acuity and decreased life quality are bothering patients and ophthalmologists for decades. After vascular endothelial growth factor (VEGF) was found to be a primary factor in promoting retinal angiogenesis, intravitreal injection of anti-VEGF drugs has been the first-line treatment. Whereas, some patients are refractory to this therapy and problems of economic burden, local complications and adverse effects promote researches into other possible targets. The vasohibin (VASH) family is a newly-investigated factor in modulating ocular angiogenesis. The family includes VASH1 and VASH2, which show opposite effects of inhibiting and accelerating angiogenesis respectively. Positive results have been reported in cellular and animal experiments. With further researches, it can be a promising future target of treating ocular neovascular diseases.

Prognostic significance of vasohibin-1 and vasohibin-2 immunohistochemical expression in gastric cancer

PURPOSE

It was recently identified that the vasohibin family may regulate angiogenesis through suppression by the vasohibin-1 gene and promotion by the vasohibin-2 gene. We assessed vasohibin expression in gastric cancer patients and its effect on their prognosis.

METHODS

We evaluated vasohibin immunohistochemical expression in 210 patients with gastric cancer, who underwent radical surgery. The patients were divided first into a vasohibin-1-positive group and a vasohibin-1-negative group, and then into groups with high or low vasohibin-2 expression, to allow us to investigate the clinicopathological factors of prognosis retrospectively.

RESULTS

There were 139 patients in the vasohibin-1-positive group and 71 patients in the vasohibin-1-negative group, among which there were and 108 with high vasohibin-2 expression and 102 with low vasohibin-2 expression. Vasohibin-1 was associated with Ly (P = 0.003) and pT (P = 0.037), whereas vasohibin-2 was associated with Ly (P < 0.001), V (P < 0.001) and pStage (P < 0.001). Overall, cancer-specific and relapse-free survival rates were lower in the vasohibin-1-positive (P = 0.034, P < 0.001, P = 0.002, respectively) and high vasohibin-2 expression (P = 0.004, P = 0.003, P < 0.001, respectively) groups. Multivariate analysis revealed that vasohibin-1 expression was associated with cancer-specific (P = 0.014, hazard ratio [HR] 4.454) and relapse-free (P = 0.035, HR 2.557) survival and vasohibin-2 expression tended to influence relapse-free survival (P = 0.051, HR 2.061). Grouping patients by vasohibin expression status combinations showed correlation among their expressions (P = 0.005). Overall, cancer-specific and relapse-free survival rates were lowest in the vasohibin-1-positive and high vasohibin-2 expression group.

CONCLUSION

Our findings demonstrate that vasohibin-1 and vasohibin-2 could be novel biomarkers for predicting gastric cancer prognosis.

Vasohibin-2 plays an essential role in metastasis of pancreatic ductal adenocarcinoma

Vasohibin-2 (VASH2) is expressed in various cancers and promotes their progression. We recently reported that pancreatic cancer patients with higher VASH2 expression show poorer prognosis. Herein, we sought to characterize the role of VASH2 in pancreatic cancer. We used LSL-Kras^G12D ; LSL-Trp53^R172H ; Pdx-1-Cre (KPC) mice, a mouse model of pancreatic ductal adenocarcinoma (PDAC), and cells isolated from them (KPC cells). Knockdown of Vash2 from PDAC cells did not affect their proliferation, but decreased their migration. When Vash2-knockdown PDAC cells were orthotopically inoculated, liver metastasis and peritoneal dissemination were reduced, and the survival period was significantly prolonged. When KPC mice were crossed with Vash2-deficient mice, metastasis was significantly decreased in Vash2-deficient KPC mice. VASH2 was recently identified to have tubulin carboxypeptidase activity. VASH2 knockdown decreased, whereas VASH2 overexpression increased tubulin detyrosination of PDAC cells, and tubulin carboxypeptidase (TCP) inhibitor parthenolide inhibited VASH2-induced cell migration. We next clarified its role in the tumor microenvironment. Tumor angiogenesis was significantly abrogated in vivo when VASH2 was knocked down or deleted. We further examined genes downregulated by Vash2 knockdown in KPC cells, and found chemokines and cytokines that were responsible for the recruitment of myeloid derived suppressor cells (MDSC). Indeed, MDSC were accumulated in PDAC of KPC mice, and they were significantly decreased in Vash2-deficient KPC mice. These findings suggest that VASH2 plays an essential role in the metastasis of PDAC with multiple effects on both cancer cells and the tumor microenvironment, including tubulin detyrosination, tumor angiogenesis and evasion of tumor immunity.

VASH2 Promotes Cell Proliferation and Resistance to Doxorubicin in Non-Small Cell Lung Cancer via AKT Signaling

Vasohibin2 (VASH2), a proangiogenic factor, has been demonstrated to play an oncogenic role in some common human cancers. However, the detailed function of VASH2 in non-small cell lung cancer (NSCLC) has not previously been studied. In this study, we found that VASH2 was significantly upregulated in NSCLC tissues and cell lines, and its increased expression was associated with NSCLC progression and poor prognosis of patients. Knockdown of VASH2 markedly inhibited cell proliferation and P-glycoprotein expression in NSCLC cells. Overexpression of VASH2 enhanced cell proliferation, P-glycoprotein expression, as well as doxorubicin resistance in NSCLC cells. Moreover, the expression levels of VASH2 were significantly increased in newly established doxorubicin-resistant NSCLC cells. Molecular mechanism investigation revealed that inhibition of VASH2 expression in NSCLC cells suppressed the activity of AKT signaling, and overexpression of VASH2 enhanced the activity of AKT signaling. We further showed that downregulation of AKT signaling activity using AKT inhibitor LY294002 markedly inhibited NSCLC cell proliferation and resistance to doxorubicin induced by VASH2. In conclusion, the findings in the present study indicate that VASH2 promotes NSCLC cell proliferation and resistance to doxorubicin via modulation of AKT signaling. Thus, we suggest that VASH2 may become a potential therapeutic target for the treatment of NSCLC.

Vasohibin 2 promotes malignant behaviors of pancreatic cancer cells by inducing epithelial-mesenchymal transition via Hedgehog signaling pathway

Background

Based on previous findings, we hypothesized that Vasohibin 2 (VASH2) protein may induce epithelial‐mesenchymal transition (EMT) of pancreatic cancer (PC) cells by promoting the malignant behaviors of these cells. The present study aimed to test this hypothesis and explore the possible mechanisms involved.

Methods

The expression of VASH2 in PC tissues and cell lines was detected by quantitative real‐time PCR and Western blot. PC cells with overexpression or knockdown of VASH2 were used to examine the involvement of VASH2 in EMT by detecting the expression of epithelial (E‐cadherin) and mesenchymal (vimentin) markers and EMT‐related transcription factor ZEB1/2, in gemcitabine resistance and tumor cell invasion by apoptosis and invasion assays, and in cancer stem cell‐like phenotypes by detecting the proportion of CD24⁺CD44⁺ and side population (SP) cells in PC cells with flow cytometry. The impact of VASH2 overexpression and knockdown on components of the Hedgehog signaling pathway was also assessed.

Results

We found that VASH2 was highly expressed in PC tissues and cells. It promoted the EMT of PC cells by altering ZEB1/2 expression. VASH2 also stimulated invasion and chemotherapeutic resistance of PC cells and increased the proportion of cancer stem‐like cells in PC cells. VASH2 did so by upregulating the expression of multiple molecules in the Hedgehog signaling pathway of PC cells.

Conclusion

VASH2 promotes malignant behaviors of PC cells by inducing EMT via activation of the Hedgehog signaling pathway.

Endogenous Antiangiogenic Factors in Chronic Kidney Disease: Potential Biomarkers of Progression

Chronic kidney disease (CKD) is a major global health problem. Unless intensive intervention is initiated, some patients can rapidly progress to end-stage kidney disease. However, it is often difficult to predict renal outcomes using conventional laboratory tests in individuals with CKD. Therefore, many researchers have been searching for novel biomarkers to predict the progression of CKD. Angiogenesis is involved in physiological and pathological processes in the kidney and is regulated by the balance between a proangiogenic factor, vascular endothelial growth factor (VEGF)-A, and various endogenous antiangiogenic factors. In recent reports using genetically engineered mice, the roles of these antiangiogenic factors in the pathogenesis of kidney disease have become increasingly clear. In addition, recent clinical studies have demonstrated associations between circulating levels of antiangiogenic factors and renal dysfunction in CKD patients. In this review, we summarize recent advances in the study of representative endogenous antiangiogenic factors, including soluble fms-related tyrosine kinase 1, soluble endoglin, pigment epithelium-derived factor, VEGF-A₁₆₅b, endostatin, and vasohibin-1, in associations with kidney diseases and discuss their predictive potentials as biomarkers of progression of CKD.

Double-Face of Vasohibin-1 for the Maintenance of Vascular Homeostasis and Healthy Longevity

The structural and functional integrity of endothelium is essential for the maintenance of vascular health. Vasohibin-1 (VASH1), originally isolated as an endothelium-derived angiogenesis inhibitor, has another function to promote stress tolerance of endothelial cells (ECs), and these functions are critical for the maintenance of vascular homeostasis preventing both pathological angiogenesis and stress-induced vascular diseases. The expression of VASH1 is downregulated during replicative senescence of ECs by the alteration of microRNA expression, and this age-associated downregulation of VASH1 might be a risk of deterioration of vascular homeostasis and age-related vascular diseases. Contrary to this expectation, the lack of Vash1 gene in mice exhibited healthy longevity. Thus, VASH1 has double-face for the maintenance of vascular homeostasis and healthy longevity. This feature of VASH1 and its mechanism will be described in this mini review.

Deletion of pro-angiogenic factor vasohibin-2 ameliorates glomerular alterations in a mouse diabetic nephropathy model

Angiogenesis has been implicated in glomerular alterations in the early stage of diabetic nephropathy. We previously reported the renoprotective effects of vasohibin-1 (VASH1), which is a novel angiogenesis inhibitor derived from endothelial cells, on diabetic nephropathy progression. Vasohibin-2 (VASH2) was originally identified as a VASH1 homolog and possesses pro-angiogenic activity in contrast to VASH1. In addition, VASH2 was recently shown to promote epithelial-to-mesenchymal transition via enhanced transforming growth factor (TGF)-β signaling in cancer cells. Herein, we investigated the pathogenic roles of VASH2 in diabetic nephropathy using VAHS2-deficient mice. The type 1 diabetes model was induced by intraperitoneal injections of streptozotocin in VASH2 homozygous knockout (VASH2^LacZ/LacZ) or wild-type mice. These mice were euthanized 16 weeks after inducing hyperglycemia. Increased urine albumin excretion and creatinine clearance observed in diabetic wild-type mice were significantly prevented in diabetic VASH2-deficient mice. Accordingly, diabetes-induced increase in glomerular volume and reduction in glomerular slit-diaphragm density were significantly improved in VASH2 knockout mice. Increased glomerular endothelial area was also suppressed in VASH2-deficient mice, in association with inhibition of enhanced vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2), but not VEGF level. Furthermore, glomerular accumulation of mesangial matrix, including type IV collagen, and increased expression of TGF-β were improved in diabetic VASH2 knockout mice compared with diabetic wild-type mice. Based on the immunofluorescence findings, endogenous VASH2 localization in glomeruli was consistent with mesangial cells. Human mesangial cells (HMCs) were cultured under high glucose condition in in vitro experiments. Transfection of VASH2 small interfering RNA (siRNA) into the HMCs resulted in the suppression of type IV collagen production induced by high glucose compared with control siRNA. These results indicate that VASH2 may be involved in diabetes-induced glomerular alterations, particularly impaired filtration barrier and mesangial expansion. Therefore, VASH2 is likely to represent a promising therapeutic target for diabetic nephropathy.

Vasohibin-1 as a novel microenvironmental biomarker for patient risk reclassification in low-risk prostate cancer

Background

We previously reported high expression of vasohibin-1 (VASH1), which is specifically expressed in activated vascular endothelial cells, was a prognostic indicator of disease progression in prostate cancer. The aim of this study was to assess whether VASH1 expression at the area of normal prostatic tissue as well as that of intratumoral tissue could reflect the grade of malignancy of prostate cancer.

Results

Pathological upgrade of Gleason Score ≥7 by radical prostatectomy was observed in 48 patients (upgraded group). The median VASH1 densities of the intratumoral and normal areas were 9.7 ± 9.5 and 13.3 ± 11.8, respectively, and the median MVDs were 58.6 ± 20.3 and 64.1 ± 23.5, respectively. We detected a strong positive correlation with each other for both VASH1 density (ρ = 0.589, p < 0.001) and MVD (ρ = 0.342, p < 0.001). VASH1 density was significantly higher in the upgreaded group than in the non-upgraded group regardless of prostatic location (intratumoral area: p < 0.001, normal area: p < 0.001).

Conclusions

Even if the tumor volume was low in biopsy samples, VASH1 density reflected the grade of malignancy throughout the prostate. These results suggested that VASH1 expression could be a novel microenvironmental biomarker for patient risk reclassification in low-risk prostate cancer.

Materials and Methods

Among the 1177 patients who underwent radical prostatectomy, 104 patients diagnosed with Gleason Score ≤6 and positive cores ≤3 were included. We immunohistochemically examined the microvessels positive for anti-CD34 as microvessel density (MVD), and those with activated endothelial cells as VASH1 density using prostatic biopsy samples, and evaluated the association between their expressions and clinicopathological findings.

Vasohibins/SVBP are tubulin carboxypeptidases (TCPs) that regulate neuron differentiation

Reversible detyrosination of α-tubulin is crucial to microtubule dynamics and functions, and defects have been implicated in cancer, brain disorganization, and cardiomyopathies. The identity of the tubulin tyrosine carboxypeptidase (TCP) responsible for detyrosination has remained unclear. We used chemical proteomics with a potent irreversible inhibitor to show that the major brain TCP is a complex of vasohibin-1 (VASH1) with the small vasohibin binding protein (SVBP). VASH1 and its homolog VASH2, when complexed with SVBP, exhibited robust and specific Tyr/Phe carboxypeptidase activity on microtubules. Knockdown of vasohibins or SVBP and/or inhibitor addition in cultured neurons reduced detyrosinated α-tubulin levels and caused severe differentiation defects. Furthermore, knockdown of vasohibins disrupted neuronal migration in developing mouse neocortex. Thus, vasohibin/SVBP complexes represent long-sought TCP enzymes.

Requisite role of vasohibin-2 in spontaneous gastric cancer formation and accumulation of cancer-associated fibroblasts

The vasohibin (VASH) family consists of two genes, VASH1 and VASH2. VASH1 is mainly expressed in vascular endothelial cells and suppresses angiogenesis in an autocrine manner, whereas VASH2 is mainly expressed in cancer cells and exhibits pro‐angiogenic activity. Employing adenomatous polyposis coli gene mutant mice, we recently reported on the role of Vash2 in the spontaneous formation of intestinal tumors. In this study, we used K19‐Wnt1/C2mE (Gan) mice and examined the role of Vash2 in spontaneous gastric cancer formation. Gan mice spontaneously develop gastric tumors by activation of Wnt and prostaglandin E2 signaling pathways in gastric mucosa after 30 weeks of age. Expression of Vash2 mRNA was significantly increased in gastric tumor tissues compared with normal stomach tissues. When Gan mice were crossed with the Vash2‐deficient (Vash2^LacZ/LacZ) strain, gastric cancer formation was significantly suppressed in Vash2^LacZ/LacZGan mice. Normal composition of gastric mucosa was partially maintained in Vash2^LacZ/LacZGan mice. Knockout of Vash2 caused minimal reduction of tumor angiogenesis but a significant decrease in cancer‐associated fibroblasts (CAF) in tumor stroma. DNA microarray analysis and real‐time RT‐PCR showed that mRNA levels of epiregulin (Ereg) and interleukin‐11 (Il11) were significantly downregulated in gastric tumors of Vash2^LacZ/LacZGan mice. Furthermore, conditioned medium of gastric cancer cells stimulated migration of and α‐smooth muscle actin expression in fibroblasts, whereas conditioned medium of VASH2 knockdown cells attenuated these effects in vitro. These results suggest that VASH2 plays an important role in gastric tumor progression via the accumulation of CAF accompanying upregulation of EREG and IL‐11 expression.

The roles of vasohibin and its family members: Beyond angiogenesis modulators

Vasohibin-1 is an intrinsic angiogenesis inhibitor, and is expressed in endothelial cells via induction by pro-angiogenesis factors. It is known to inhibit several processes of angiogenesis, with different mechanisms from extrinsic angiogenesis inhibitors. Vasohibin-2 is mainly expressed by mononuclear cells which have been mobilized from bone marrow. It not only promotes angiogenesis, but also modulates the releases of FGF-2 and VEGF, which are the two major inducers for vasohibin1. Hypoxic environment induces the expression of hypoxia-inducible Factor 1α with a result of VEGF release nearly in all tumor cell lines and tissues. However, it has been observed that hypoxia reduces the inducible effects of VEGF on vasohibin, which indicates that a complicated mechanism exists in the angiogenesis. Vasohibin and its family members play important roles in both the physiological and pathological procedures, in contrary but complementary patterns. Furthermore, human aortic smooth muscle cells and fibroblast have also been detected to express vasohibin on a moderate to weak scale range. Recently, the results of an increasing number of studies in vivo have shown that vasohibin can also be detected in several cancers, and is associated with micro-vessel densities, histology grades, invasions, poor clinical features, metastasis, and dissemination in abdominal cavities, as well as EMT. In more recent reports, it has been confirmed that, along with being angiogenesis regulators, a variety of other roles have been associated with this family. The focus of this study was the upstream regulatory mechanisms of vasohibin expressions, and their role in regard to the downstream target proteins of vasohibin, especially in carcinoma. Vasohibin is considered to be an original angiogenesis inhibitor, and has a much broader significance in pathological processes. It can be taken as an independent prognostic factor, as well as a potential strategy for cancer therapy programs.

The expression of vasohibin-1 and its prognostic significance in bladder cancer

Angiogenesis is important in the development of solid tumors. Vasohibin-1 (VASH-1) is an endothelium-derived protein that acts as an inhibitor of angiogenesis in many different types of cancer. However, the expression of VASH-1 and its clinical value in bladder cancer remain unknown. The current study analyzed the expression of VASH-1, as well as the expression of the angiogenesis-related factors vascular endothelial growth factor-A, hypoxia inducible factor-1α and cluster of differentiation 34 in bladder cancer tissues from 50 patients using immunohistochemistry. The associations between the expression of these factors and the clinicopathological characteristics of the patients were assessed. The current study demonstrated that VASH-1 is primarily expressed in the cytoplasm of bladder cancer cells and in a fraction of vascular endothelial cells. Furthermore, the expression of VASH-1 was positively associated with the tumor stage (P<0.01), pathological grade (P<0.01) and distant metastasis (P<0.05) but not with patient age or sex (P>0.05). Spearman rank correlation tests indicated that levels of those four factors were positively correlated with each other. Kaplan-Meier analysis indicated that high expression of these four factors was significantly associated with lower 5-year overall survival and progression-free survival rates. Collectively, the results of the current study suggest that VASH-1 is clinically significant in bladder cancer and its high expression may predict the progression and prognosis of patients with bladder cancer. The present study also implies that VASH-1 may be a novel target for vascular targeting therapy.

Targeting human vasohibin-2 by a neutralizing monoclonal antibody for anti-cancer treatment

There are two members of the vasohibin (VASH) family, VASH1 and VASH2. VASH1 is expressed mainly in endothelial cells to inhibit angiogenesis, whereas VASH2 is expressed mainly in cancer cells to stimulate tumor growth. The aim of the present study was to establish neutralizing monoclonal antibody (mAb) against human VASH2 and apply it as an anti‐cancer treatment. We previously raised mAb against several synthetic peptides of hVASH1, and found that one of them exhibited neutralizing activity against hVASH1. Because of the similarity in the amino acid sequences between VASH1 and VASH2, we hypothesized that they shared the bioactive center. When we mutated four amino acids within the region, the mutant VASH2 lost its pro‐angiogenic activity. Therefore, we raised mAb against a synthetic peptide overlapping the mutated amino acids of hVASH2, and isolated one clone (1760) that almost completely inhibited the stimulatory effect of hVASH2 on the migration of and tube formation by endothelial cells. When we used this clone 1760 antibody for cancer treatment, the peritoneal injection of it inhibited both tumor growth and angiogenesis in a mouse xenograft model of human cancer cells. In terms of anti‐tumor activity, 25 mg/kg of clone 1760 was equivalent to 5 mg/kg of bevacizmab. From these results, we propose the targeting of human VASH2 with neutralizing mAb as a new strategy for cancer treatment.

Vasohibin-2 is required for epithelial-mesenchymal transition of ovarian cancer cells by modulating transforming growth factor-β signaling

Vasohibin‐2 (VASH2) is a homolog of VASH1, an endothelium‐derived angiogenesis inhibitor. Vasohibin‐2 is mainly expressed in cancer cells, and has been implicated in the progression of cancer by inducing angiogenesis and tumor growth. Although VASH2 has been recently reported to be involved in epithelial–mesenchymal transition (EMT), its precise roles are obscure. The aim of the present study was to clarify the role of VASH2 in the EMT of cancer cells in relation to transforming growth factor‐β (TGF‐β) signaling, which is a major stimulator of EMT. Decreased expression of VASH2 in ovarian cancer cells significantly repressed the expression of TGF‐β type I receptor, namely activin receptor‐like kinase 5. Transforming growth factor‐β1‐induced phosphorylation of Smad2 and Smad3 was markedly decreased in VASH2 knockdown cells while the expression of Smad2 and Smad3 was unchanged. Accordingly, the responses to TGF‐β1 shown by promoter assay and plasminogen activator inhibitor type 1 expression were significantly attenuated in VASH2 knockdown cells. Furthermore, knockdown of VASH2 in cancer cells abrogated the TGF‐β1‐induced reduced expression of epithelial markers including E‐cadherin, and the elevated expression of mesenchymal markers including fibronectin, ZEB2, and Snail2, suggesting that endogenous VASH2 is required for TGF‐β1‐induced EMT. In accordance with these results, the effects of TGF‐β1 on cell morphology, migration, invasion, and MMP2 expression were also abrogated when VASH2 was knocked down. These results indicate that VASH2 played a significant role in the EMT by modulating the TGF‐β signaling. We propose that VASH2 would be a novel molecular target for the prevention of EMT in cancers.

Vasohibin 2 reduces chemosensitivity to gemcitabine in pancreatic cancer cells via Jun proto-oncogene dependent transactivation of ribonucleotide reductase regulatory subunit M2

Background

Vasohibin 2 (VASH2) has previously been identified as an agiogenenic factor and a cancer related protein. Here we investigated the association of VASH2 expression and chemoresistance in pancreatic cancer.

Methods

Immunohistochemical staining for VASH2 was performed on 102 human pancreatic cancer samples. Pancreatic cancer cell line models exhibiting overexpression or knockdown of VASH2 were generated. Gene expression analyses were carried out to determine genes differentially regulated by VASH2. Putative transcription factors that are downstream mediators of gene expression regulated by VASH2 were queried bioinformatically. Dual-luciferase reporter assays and ChIP assays were performed to confirm transactivation of target genes following VASH2 overexpression or knockdown.

Results

VASH2 protein expression was higher in human pancreatic cancer than in paired adjacent tissues and elevated VASH2 levels were associated with gemcitabine chemoresistance. In cell line models of pancreatic cancer, VASH2 expression induced gemcitabine chemoresistance in vitro and in vivo. It was discovered that expression of ribonucleotide reductase regulatory subunit M2 (RRM2) is regulated by VASH2; immunohistochemical analysis demonstrated a positive association of VASH2 expression and RRM2 expression in human pancreatic cancer tissues. Bioinformatics analyses revealed that induction of the Jun proto-oncogene (JUN) by VASH2 is responsible for upregulation of RRM2 expression; this JUN-dependent regulation of RRM2 by VASH2 was confirmed by chromatin immunoprecipitation and dual luciferase reporter assays, which demonstrated that JUN directly binds with the RRM2 promoter to activate transcription.

Conclusions

These data suggest that VASH2 reduces the chemosensitivity to gemcitabine in pancreatic cancer cells via JUN-dependent transactivation of RRM2.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-017-0619-6) contains supplementary material, which is available to authorized users.

Domain architecture of vasohibins required for their chaperone-dependent unconventional extracellular release

Vasohibins (VASH1 and VASH2) are recently identified regulators of angiogenesis and cancer cell functions. They are secreted proteins without any classical secretion signal sequences, and are thought to be secreted instead via an unconventional protein secretion (UPS) pathway in a small vasohibin-binding protein (SVBP)-dependent manner. However, the precise mechanism of SVBP-dependent UPS is poorly understood. In this study, we identified a novel UPS regulatory system in which essential domain architecture (VASH-PS) of VASHs, comprising regions VASH1_91-180 and VASH2_80-169 , regulate the cytosolic punctate structure formation in the absence of SVBP. We also demonstrate that SVBP form a complex with VASH1 through the VASH1_274-282 (SIa), VASH1_139-144 (SIb), and VASH1_133-137 (SIc), leading to the dispersion in the cytosol and extracellular release of VASH1. The amino acid sequences of VASH-SIa and VASH-PS, containing SIb and SIc, are highly conserved among VASH family members in vertebrates, suggesting that SVBP-dependent UPS may be common within the VASH family. This novel UPS regulatory system may open up new avenues for understanding fundamental protein secretion in vertebrates.

Vasohibin 2 promotes epithelial-mesenchymal transition in human breast cancer via activation of transforming growth factor β 1 and hypoxia dependent repression of GATA-binding factor 3

Vasohibin 2 (VASH2) is identified as an angiogenic factor, and has been implicated in tumor angiogenesis, proliferation and epithelial-mesenchymal transition (EMT). To investigate the EMT role of VASH2 in breast cancer, we overexpressed or knocked down expression of VASH2 in human breast cancer cell lines. We observed that VASH2 induced EMT in vitro and in vivo. The transforming growth factor β1 (TGFβ1) pathway was activated by VASH2, and expression of a dominant negative TGFβ type II receptor could block VASH2-mediated EMT. In clinical breast cancer tissues VASH2 positively correlated with TGFβ1 expression, but negatively correlated with E-cadherin (a marker of EMT) expression. Under hypoxic conditions in vitro or in vivo, we found that down-regulation of estrogen receptor 1 (ESR1) in VASH2 overexpressing ESR1 positive cells suppressed E-cadherin. Correlation coefficient analysis indicated that VASH2 and ESR1 expression were negatively correlated in clinical human breast cancer tissues. Further study revealed that a transcription factor of ESR1, GATA-binding factor 3 (GATA3), was down-regulated by VASH2 under hypoxia or in vivo. These findings suggest that VASH2 drives breast cancer cells to undergo EMT by activation of the TGFβ1 pathway and hypoxia dependent repression GATA3-ESR1 pathway, leading to cancer metastasis.

Expression pattern of HIF1alpha and vasohibins during follicle maturation and corpus luteum function in the bovine ovary

The aim of this study was to characterize expression patterns of hypoxia-inducible factor-1alpha (HIF1A) and vasohibin family members (VASH1 and VASH2) during different stages of ovarian function in cow. Experiment 1: Antral follicle classification occurred by follicle size and estradiol-17beta (E2) concentration in the follicular fluid into 5 groups (<0.5, 0.5-5, 5-40, 40-180 and >180 E2 ng/ml). Experiment 2: Corpora lutea (CL) were assigned to the following stages: days 1-2, 3-4, 5-7, 8-12, 13-16 and >18 (after regression) of oestrous cycle and of pregnancy (months 1-2, 3-4, 6-7, >8). Experiment 3: Cows on days 8-12 were injected with a prostaglandin F2alpha (PGF) analogue and CL were collected before and 0.5, 2, 4, 12, 24, 48 and 64 hr after PGF injection. Expression of mRNA was measured by qPCR, steroid hormone concentration by EIA and localization by immunohistochemistry. HIF1A mRNA expression in our study increases significantly in follicles during final maturation. The highest HIF1A mRNA expression was detected during the early luteal phase, followed by a significant decrease afterwards. In contrast, the mRNA of vasohibins in small follicle was high, followed by a continuous and significant downregulation in preovulatory follicles. The obtained results show a remarkable inverse expression and localization pattern of HIF1A and vasohibins during different stages of ovarian function in cow. These results lead to the assumption that the examined factors are involved in the local mechanisms regulating angiogenesis and that the interactions between proangiogenic (HIF1A) and antiangiogenic (vasohibins) factors impact all stages of bovine ovary function.

Vasohibins: new transglutaminase-like cysteine proteases possessing a non-canonical Cys-His-Ser catalytic triad

Vasohibin-1 and Vasohibin-2 regulate angiogenesis, tumour growth and metastasis. Their molecular functions, however, were previously unknown, in large part owing to their perceived lack of homology to proteins of known structure and function. To identify their functional amino acids and domains, their molecular activity and their evolutionary history, we undertook an in-depth analysis of Vasohibin sequences. We find that Vasohibin proteins are previously undetected members of the transglutaminase-like cysteine protease superfamily, and all possess a non-canonical Cys-His-Ser catalytic triad. We further propose a calcium-dependent activation mechanism for Vasohibin proteins. These findings can now be used to design constructs for protein structure determination and to develop enzyme inhibitors as angiogenic regulators to treat metastasis and tumour growth.

CONTACT

luis.sanchezpulido@dpag.ox.ac.uk

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Inhibition of IGF-1-Mediated Cellular Migration and Invasion by Migracin A in Ovarian Clear Cell Carcinoma Cells

Previously we isolated migracin A from a Streptomyces culture filtrate as an inhibitor of cancer cell migration. In the present research, we found that migracin A inhibited migration and invasion of ovarian clear cell carcinoma ES-2 cells. In the course of our mechanistic study, migracin A was shown to enhance vasohibin-1 expression in an angiogenesis array. We also confirmed that it increased the mRNA expression of this protein. Moreover, overexpression of vasohibin-1 lowered the migration but not the invasion of ES-2 cells. Then, we looked for another target protein employing a motility array, and found that migracin A lowered the IGF-1 expression. Knockdown of IGF-1 by siRNA decreased the migration and invasion of ES-2 cells. Migracin A also decreased Akt phosphorylation involved in the downstream signaling. Crosstalk analysis indicated that overexpression of vasohibin-1 decreased the IGF-1 expression. On the other hand, it showed no direct anticancer activity in terms of the ES-2 growth in agar. Migracin A inhibited the migration and IGF-1 expression in not only ES-2 but also another ovarian clear cell carcinoma JHOC-5 cells. In addition, it also inhibited capillary tube formation of human umbilical vein endothelial cells. Since its cytotoxicity is very low, migracin A may be a candidate for an anti-metastasis agent not exhibiting prominent toxicity.

Novel Link between Inhibition of Angiogenesis and Tolerance to Vascular Stress

The functional integrity of the vascular endothelium is an essential component required for the maintenance of vascular health, thus counteracting the onset of vascular diseases, including atherosclerosis and vascular complications of diabetes. In light of this important role, the vascular endothelium is expected to have a self-defense system. One candidate factor of such a system is vasohibin-1 (VASH1), a protein that is preferentially expressed in vascular endothelial cells (ECs). The unique features of VASH1 are its anti-angiogenic activity and ability to promote the stress tolerance and survival of ECs. This review summarizes current knowledge regarding VASH1 in terms of its roles in maintaining vascular integrity and protecting the vasculature against various forms of stress.

MiR200-upregulated Vasohibin 2 promotes the malignant transformation of tumors by inducing epithelial-mesenchymal transition in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) typically relies on tumor transformation and angiogenesis for its malignant behavior, including growth and metastasis. Previously, we reported that Vasohibin2 (VASH2) is preferentially expressed in hepatocellular carcinoma (HCC) tumor tissues and promotes angiogenesis. Here, we further investigated the role of VASH2 in HCC tumor progression.

Results

Bioinformatics analyses and luciferase reporter gene assays confirmed the post-transcriptional regulation of VASH2 by miR-200a/b/c. We then used HepG2 and Hep3B cells, two representative hepatic cancer cell lines, to examine the role of VASH2 in tumors. VASH2 knockdown in HepG2 cells inhibited epithelial-mesenchymal transition (EMT), but VASH2 overexpression in Hep3B cells promoted EMT. Western blot analyses showed that VASH2 promoted EMT through the ZEB1/2 pathway.

Conclusion

VASH2 promoted invasion, reduced apoptosis and increased the proportion of stem cells in vitro and in vivo. These results indicated that VASH2 expression in HCC cells promotes the malignant transformation of tumors by inducing EMT.

Electronic supplementary material

The online version of this article (doi:10.1186/s12964-014-0062-x) contains supplementary material, which is available to authorized users.

Correlation of tumor-infiltrative lymphocyte subtypes alteration with neoangiogenesis before and after neoadjuvant chemotherapy treatment in breast cancer patients

The two most important factors in tumor-stromal interactions are tumor-infiltrating lymphocytes (TIL) and neoangiogenesis (NAng). While changes of these parameters in responders of neoadjuvant chemotherapy (NCTx) have been reported, their correlation with pathological response in breast cancer (BC) patients treated with NCTx have not been described. We therefore evaluated alterations of the TIL subtypes ratio and alterations of NAng using the vasohibin-1-positive ratio (VPR) in BC patients during the course of NCTx. To this aim we used: (i) double immunohistochemistry of CD8 cytotoxic T cells and T regulatory cells (Treg) with Foxp3, determining the CD8+/Foxp3 ratio; (ii) immunostaining of CD31 and vasohibin-1, yielding the VPR, which reflects the NAng status. Changes between the CD8+/Foxp3 ratio and VPR before and after therapy were then correlated with the pathological response of the patients. A concomitant significant decrement of Foxp3 and NAng, represented by VPR, were detected only in NCTx pathological responders (p<0.001 and p=0.044, respectively). The CD8+/Foxp3 ratio increased in both responders and non-responders, but to greater extent in responders (p=0.02). The changes of VPR in the NCTx-treated group differed from those recorded for the patients treated with aromatase inhibitors and shown in our earlier study; this indicates that the reactions of the tumor-stromal interaction to therapy were different among different treatments in BC patients. Changes in Foxp3 and VPR in responders may reflect the dynamic activity of tumor stroma and host immune response to tumor antigens in the tumor microenvironment in response to the NCTx. VPR can be a potential surrogate marker in BC specimens for predicting the response to NCTx, incorporating both features of carcinoma and stromal cells.

Role of the vasohibin family in the regulation of fetoplacental vascularization and syncytiotrophoblast formation

Vasohibin-1 (VASH1) and vasohibin-2 (VASH2), the 2 members of the vasohibin family, have been identified as novel regulators of angiogenesis. VASH1 ceases angiogenesis, whereas VASH2 stimulates sprouting. Here we characterized their functional role in the placenta. Immunohistochemical analysis of human placental tissue clarified their distinctive localization; VASH1 in endothelial cells and VASH2 in trophoblasts. We then used a mouse model to explore their function. Wild-type, Vash1^(−/−), and Vash2^(−/−) mice on a C57BL6 background were used in their first pregnancy. As expected, the fetal vascular area was increased in the Vash1^(−/−) mice, whereas it was decreased in the Vash2^(−/−) mice relative to wild-type. In addition, we noticed that the Vash2^(−/−) mice at 18.5dpc displayed thinner villi of the labyrinth and larger maternal lacunae. Careful observation by an electron microscopy revealed that the syncytiotrophoblast formation was defective in the Vash2^(−/−) mice. To test the possible involvement of VASH2 in the syncytiotrophoblast formation, we examined the fusion of BeWo cells, a human trophoblastoid choriocarcinoma cell line. The forskolin treatment induced the fusion of BeWo cells, and the knockdown of VASH2 expression significantly inhibited this cell fusion. Conversely, the overexpression of VASH2 by the infection with adenovirus vector encoding human VASH2 gene significantly increased the fusion of BeWo cells. Glial cell missing-1 and endogenous retrovirus envelope glycoprotein Syncytin 1 and Syncytin 2 are known to be involved in the fusion of trophoblasts. However, VASH2 did not alter their expression in BeWo cells. These results indicate that VASH1 and VASH2 showed distinctive localization and opposing function on the fetoplacental vascularization. Moreover, our study shows for the first time that VASH2 expressed in trophoblasts is involved in the regulation of cell fusion for syncytiotrophoblast formation.

Vasohibin‑2 promotes proliferation in human breast cancer cells via upregulation of fibroblast growth factor‑2 and growth/differentiation factor‑15 expression

Vasohibin‑2 (VASH2) is an angiogenic factor, and has been previously reported to be a cancer‑related gene, with cytoplasmic and karyotypic forms. In the current study VASH2 expression in human breast cancer tissue and adjacent non‑cancerous tissue was investigated with immunohistochemistry. MCF‑7 and BT474 human breast cancer cells were transfected with lentiviral constructs to generate in vitro VASH2 overexpression and knockdown models. In addition, BALB/cA nude mice were inoculated subcutaneously with transfected cells to generate in vivo models of VASH2 overexpression and knockdown. The effect of VASH2 on cell proliferation was investigated using a bromodeoxyuridine assay in vitro and immunohistochemistry of Ki67 in xenograft tumors. Growth factors were investigated using a human growth factor array, and certain factors were further confirmed by an immunoblot. The results indicated that the expression level of cytoplasmic VASH2 was higher in breast cancer tissues with a Ki67 (a proliferation marker) level of ≥14%, compared with tissues with a Ki67 level of <14%. VASH2 induced proliferation in vitro and in vivo. Four growth factors activated by VASH2 were identified as follows: Fibroblast growth factor 2 (FGF2), growth/differentiation factor‑15 (GDF15), insulin‑like growth factor‑binding protein (IGFBP)3 and IGFBP6. FGF2 and GDF15 may contribute to VASH2‑induced proliferation. The current study identified a novel role for VASH2 in human breast cancer, and this knowledge suggests that VASH2 may be a novel target in breast cancer treatment.

Vasohibin 2 decreases the cisplatin sensitivity of hepatocarcinoma cell line by downregulating p53

Hepatocellular carcinoma (HCC) is a prevalent problem worldwide. Chemotherapy, especially cisplatin (CDDP)-based systemic chemotherapy, is the best option for advanced liver cancer. However, CDDP resistance is becoming common and hindering the clinical application of CDDP. Meanwhile, no consensus has been reached regarding the chemotherapeutic use of vasohibin 2 (VASH2), which promotes the angiogenesis and proliferation of cancer cells. In this work, a tissue microarray was used to observe VASH2 and its possible role in cancer treatment. Results showed that VASH2 was highly expressed in HCC tissues and was significantly correlated with cancer differentiation. To further investigate the efficacy and mechanism of the combination of VASH2 with anti-cancer drugs in liver cancer cells, we stably built VASH2 overexpression and knockdown cell lines. We found that VASH2 can influence the CDDP sensitivity and that the cell overexpression of VASH2 had a higher cell viability and lower apoptosis rate after CDDP exposure. We also observed that VASH2 overexpression downregulated wild-type p53, as well as suppressed the expression of the pro-apoptotic protein BCL2-associated X protein (Bax) and cleaved caspase-3 (CC-3) after treatment by CDDP. Conversely, the knockdown of VASH2 significantly inhibited these effects. In an in vivo chemosensitivity study, nude mice were subcutaneously injected with tumor cells and received CDDP treatment through intraperitoneal administration every 3 days. We found that VASH2 knockdown markedly limited the tumor growth and enhanced the CDDP toxicity and apoptosis of tumor cells. Western blot analysis revealed that tumor cells with downregulated VASH2 had a higher expression of wild-type p53, Bax, and CC-3 than control cells. Overall, our results indicated the novel roles of VASH2 in the chemoresistance of hepatocarcinoma cells to CDDP and suggested that VASH2 may be a promising anticancer target.

Generation and characterization of rabbit polyclonal antibodies against Vasohibin-2 for determination of its intracellular localization

Vasohibin-2 was recently identified as an important pro-angiogenesis factor in solid tumor and intracellular localization of its variants is important for elucidating the downstream mechanism(s) of its effects. Currently there are no reported antibodies affordable for intracellular localization. The aim of this study was to generate and characterize polyclonal antibodies against Vasohibin-2 and to determine the intracellular localization of Vasohibin-2. In this study, two polypeptides were synthesized and one prokaryotic Vasohibin-2 recombinant protein was custom-made. New Zealand rabbits were immunized with the polypeptide mixture and prokaryotic recombinant protein, respectively. The purified antibodies from the antiserum were validated by ELISA, western blotting (WB), immunofluorescence (IF), immunohistochemistry (IHC) and immunoprecipitation (IP). In order to determine intracellular localization, the cytoplasmic and nuclear proteins of the human liver cancer cell line HepG2 were isolated for the detection of Vasohibin-2 by western blotting. Vasohibin-2 cDNA, coding for 311 and 355 amino acid residues, fused with or without a DDK/V5 tag at the c-terminus, respectively, was cloned into the Lv-CMV-EGFP vector. Lentiviruses were successfully packaged. Vasohibin-2-overexpressing HepG2-VASH2 (355 amino acid residues) and HepG2-VASH2-V5 (311 amino acid residues fused with V5 tag at the c-terminus) human liver cancer cell lines were established. Approximately 1-2x106 HepG2, HepG2-VASH2 and HepG2-VASH2-V5 cells were injected subcutaneously into the flanks of BALB/c nude mice. Xenograft tumors were harvested for immunohistochemistry. HepG2 cells were transiently transfected with the Lv-CMV-EGFP vectors containing Vasohibin-2 cDNA (coding for 311/355 amino acid residues with a DDK tag at the c-terminal), followed by anti-DDK immunofluorescence. The antibodies obtained were able to detect human VASH2 successfully as applied in western blotting, IF, IHC and IP. Results from IF, IHC and WB (post cytoplasmic/nuclear protein isolation) showed a quite different intracellular localization of VASH2 protein. The VASH2 (with 355 amino acid residues) was located in the cytoplasm while VASH2 (with 311 amino acid residues) was located in the nucleus. The former was found to be a relatively low abundance protein. We successfully generated three rabbit anti-human Vasohibin-2 polyclonal antibodies which can be used for western blotting, IF, IP and IHC. These antibodies will provide a convenient tool for further studies on Vasohibin-2. This is the first study to report differences in the intracellular localization of the VASH2 protein and, hence, a new research direction on the study of VASH2.

The vasohibin family: a novel family for angiogenesis regulation

Angiogenesis, a formation of neovessels, is regulated by the local balance between angiogenesis stimulators and inhibitors. A number of such endogenous regulators of angiogenesis have been found in the body. Recently, vasohibin-1 (VASH1) was isolated as a negative feedback regulator of angiogenesis produced by endothelial cells (ECs) and subsequently vasohibin-2 (VASH2) as a homologue of VASH1. It was then explored that VASH1 is expressed in ECs to terminate angiogenesis, whereas VASH2 is expressed in cells other than ECs to promote angiogenesis in the mouse model of angiogenesis. This review will focus on the vasohibin family members, which are novel regulators of angiogenesis.

Angiogenesis inhibitor vasohibin-1 enhances stress resistance of endothelial cells via induction of SOD2 and SIRT1

Vasohibin-1 (VASH1) is isolated as an endothelial cell (EC)-produced angiogenesis inhibitor. We questioned whether VASH1 plays any role besides angiogenesis inhibition, knocked-down or overexpressed VASH1 in ECs, and examined the changes of EC property. Knock-down of VASH1 induced premature senescence of ECs, and those ECs were easily killed by cellular stresses. In contrast, overexpression of VASH1 made ECs resistant to premature senescence and cell death caused by cellular stresses. The synthesis of VASH1 was regulated by HuR-mediated post-transcriptional regulation. We sought to define the underlying mechanism. VASH1 increased the expression of (superoxide dismutase 2) SOD2, an enzyme known to quench reactive oxygen species (ROS). Simultaneously, VASH1 augmented the synthesis of sirtuin 1 (SIRT1), an anti-aging protein, which improved stress tolerance. Paraquat generates ROS and causes organ damage when administered in vivo. More VASH1 (+/-) mice died due to acute lung injury caused by paraquat. Intratracheal administration of an adenovirus vector encoding human VASH1 augmented SOD2 and SIRT1 expression in the lungs and prevented acute lung injury caused by paraquat. Thus, VASH1 is a critical factor that improves the stress tolerance of ECs via the induction of SOD2 and SIRT1.