Hemangioma-derived Stem Cells Research Articles

Inhibiting Interleukin-6/Signal Transducers and Activators of Transduction-3/Hypoxia-Inducible Factor-1α Signaling Pathway Suppressed the Growth of Infantile Hemangioma.

This study aims to evaluate the expression of interleukin 6 (IL-6) in patients with infantile hemangioma (IH) and investigate the role of the IL-6/signal transducers and activators of transduction-3 (STAT3)/hypoxia-inducible factor-1α (HIF-1α) pathways in the progression of IH. Serum samples were obtained from the patients with IH and normal infants to measure IL-6 expression. Hemangioma-derived stem cells (HemSCs) were transfected with small interfering RNA (siRNA) targeting IL-6, HIF-1α, or STAT3. Then, cell viability and wound healing assays were conducted. After that, the HemSC tumor mouse model was established. The in vivo anticancer effect of the IL-6 inhibitor was investigated. The patients with IH had much higher IL-6 levels compared with the healthy controls (p = 0.005). HemSCs transfected with IL-6 siRNA had significantly lower viability and migration rates than normal HemSCs. HemSCs transfected with STAT3 siRNA or HIF-1α siRNA had similar tendencies. On tumor-bearing mice, the IL-6 inhibitor treatment significantly delayed tumor growth. Compared with the control group, caspase-3 was significantly increased in the IL-6 inhibitor group (p < 0.05), whereas Ki-67 was decreased in the IL-6 inhibitor group (p < 0.05). In the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, the IL-6 inhibitor group had much higher apoptosis rates than the controls (p < 0.05). Our findings indicate that inhibiting the IL-6/STAT3/HIF-1α signaling pathways could suppress IH growth.

Hypoxia-Induced Cyr61/CCN1 Production in Infantile Hemangioma.

Hypoxia may play a role in the pathogenesis of infantile hemangioma. Cysteine-rich angiogenic inducer 61 (Cyr61), or CCN1, can be induced under hypoxic conditions in several types of cells. However, whether CCN1 has any impact on infantile hemangioma remains unknown. This study aims to explore the expression of CCN1 in infantile hemangioma and to investigate the effect of hypoxia on CCN1 and vascular endothelial growth factor-A (VEGF-A) production. Hemangioma-derived endothelial cells and hemangioma-derived stem cells were isolated from surgical specimens of proliferative infantile hemangioma. RNA extracted from infantile hemangioma tissue, hemangioma-derived endothelial cells, and hemangioma-derived stem cells was used to analyze gene expression by real-time polymerase chain reaction. The effects of CCN1 blockade were examined in hemangioma-derived stem cells. Immunostaining, immunoblotting, and enzyme-linked immunosorbent assays were used to assess protein expression. By double-label immunofluorescence staining, the authors first identified that CCN1 was abundant in proliferative infantile hemangioma lesions and colocalized well with immature microvessels. The authors found that the mRNA level of CCN1 in proliferative infantile hemangioma was significantly higher than in healthy controls, as was involuting infantile hemangioma. Treatment with the hypoxia inducer cobalt chloride dramatically increased CCN1 production in hemangioma-derived endothelial cells in a time-dependent manner. Furthermore, blocking or knockdown of CCN1 expression reduced the expression of VEGF-A in hemangioma-derived stem cells. Lastly, the signaling pathway study showed that CCN1 up-regulation of VEGF-A synthesis in hemangioma-derived stem cells depends on nuclear factor-κB and JNK activation. These findings provide new evidence that CCN1 participates in the crosstalk between hemangioma-derived endothelial cells and hemangioma-derived stem cells through promoting VEGF-A expression in the hypoxic environment of infantile hemangioma angiogenesis and vasculogenesis. Targeting of CCN1 might be a novel therapeutic strategy for infantile hemangioma.

Exosome-derived miR-196b-5p facilitates intercellular interaction in infantile hemangioma via down-regulating CDKN1B.

BackgroundThough infantile hemangioma (IH) is a common benign vascular tumor, its pathogenesis remains unclear. This study explored the function of hemangioma-derived stem cells (HemSCs) derived exosomes, which exerted an intercellular effect on hemangioma-derived endothelial cells (HemECs).MethodsFirst, HemSCs and HemECs were extracted and cultured. HemSCs derived exosomes (HemSCs-exos) were harvested. miRNA sequencing and target prediction were used to explore differentially expressed miRNAs and potential binding targets. After HemECs were co-cultured with HemSCs-exos, a series of in vitro assays were then performed including cell counting kit-8 (CCK-8) assay, cell apoptosis assay, cell cycle assay and tube formation assay to evaluate proliferation, angiogenesis abilities, etc. qRT-PCR and Western blot were conducted to detect the expression level of target genes and proteins.ResultsAfter co-culturing with HemSCs-exos, proliferation, and angiogenesis abilities of HemECs were enhanced, while apoptosis and cell cycle arrest rate were decreased. MiR-196b-5p was observed to be significantly highly expressed in HemSCs-exos. CDKN1B was identified as the binding target of miR-196b-5p. HemECs’ proliferation and angiogenesis abilities were elevated when co-cultured with exosomes from HemSCs transfected with miR-196b-5p mimic. In addition, apoptosis rate declined, and lower cells were arrested in G0/G1 phases. Cyclin E, bcl-2 were significantly highly expressed, whereas p27, Bax expression were significantly down-regulated. The positive effect of miR-196b-5p in HemSCs-exos was dramatically reversed when HemECs were transfected with oe-CDKN1B.ConclusionsThe current study found a novel intercellular interaction between IH cells. Briefly, exosome-derived miRNA-196b-5p in HemSCs could facilitate proliferation and angiogenesis abilities, and attenuate apoptosis and cell cycle repression rate of HemECs by directly binding with CDKN1B.

The flavonoid luteolin suppresses infantile hemangioma by targeting FZD6 in the Wnt pathway.

Infantile hemangioma is the most common vascular tumor of childhood. It is characterized by clinical expansion of endothelial cells and promoted by angiogenic factors. Luteolin is a flavonoid compound that carries anti-cancer and anti-angiogenesis properties. The study aimed to investigate the effect of luteolin in treating infantile hemangioma. We first tested the effect of luteolin on cell proliferative potential and VEGFA expression in hemangioma-derived stem cells (HemSCs). We then examined the efficacy of systemic application of luteolin in a murine hemangioma model. We then identified the downstream factor regulated by luteolin in HemSCs and validated its causative relationship with knock-down method in both in vitro and in vivo models. We also investigated the protein expression change of this targeting factor in proliferating hemangiomas. Luteolin inhibited HemSC growth and suppressed VEGF-A expression in a dose-dependent manner. Luteolin inhibited microvessel formation and de novo vasculogenesis in the murine model. FZD6 was induced by luteolin and exerted the anti-angiogenesis effect in our tumor models. Lastly, FZD6 level was repressed in the clinical tissues of human proliferating hemangiomas. Luteolin is a promising new agent to treat infantile hemangioma. Targeting the Wnt pathway may represent a potential therapeutic strategic to inhibit angiogenesis in proliferating hemangiomas.

Increased Angiopietin-2 expression, enhanced proliferation, migration and formation of blood vessels in hemangioma-derived stem cells

Objective To investigate the effect of Angiopoietin-2 (Ang2) up-regulation on the biological function of hemangioma stem cells (HemSCs). Methods HemSCs was isolated and purified by enzyme digestion and immunomagnetic beads sorting. HemSCs was stably up-regulated by Ang2 by lentiviral transfection. The expression level of secreted Ang2 and vascular endothelial growth factor (VEGF) in HemSCs up-regulated by Ang2 was detected by enzyme linked immunosorbent assay (ELISA) method. EDU method The Trangswell method was used to observe the proliferation and migration ability of HemSCs cells up-regulated by Ang2. The tumor formation of nude mice was observed by single cell suspension. The tumorigenic ability of HemSCs was up-regulated by Ang2. The expression of key target proteins in phosphatidylinositol 3 kinase (PI3K)/serine-threonine protein kinase (Akt) cell signaling pathway was detected by Western blotting. Results The proliferation of HemSCs cells up-regulated by Ang2 was enhanced (blank group: 117.000±3.786, control group: 126.000±3.464, experimental group: 179.667±2.603, P<0.01), and migration ability was enhanced (blank group: 102.667±2.028, control group: 108.000±2.646, experimental group: 308.667±2.603, P<0.01); Ang2 in HemSCs Ang2↑ group (blank group: 60.103±0.361, control group: 69.343±0.526, experimental group: 1 962.440±43.205, P<0.01), VEGF (The blank group: 92.667±3.480, the control group: 91.000±1.523, the experimental group: 455.000±15.100, P<0.01) the expression of secreted protein was up-regulated; PI3K-Akt signaling pathway-related protein: Akt1 (blank group: 0.612±0.163, control group: 0.624±0.163, experiment Group: 0. 907±0.162, P<0.01), PI3K (blank group: 0.624±0.163, control group: 0.474±0.163, experimental group: 0.766±0.162, P<0.01), PI3KR5 (blank group: 0.505±0.163, control group: 0.405±0.163, Experimental group: 0.890±0.162, P<0.01), PAkt (blank group: 0.549±0.163, control group: 0.644±0.163, experimental group: 0.684±0.162, P<0.01), p38 (blank group: 0.618±0.163, control Group: 0.759±0.163, experimental group: 0. 947±0.162, P<0.01) Enhanced expression in HemSCs Ang2↑ group. Conclusion Upregulation of Ang2 can enhanced HemSCs proliferation, migration, in vivo angiogenesis; through PI3K-Akt signaling pathway Development has an impact. Key words: Hemangioma; Stem cell; Ang-Tie2 lentivirus; Signaling pathway

The sustained and targeted treatment of hemangiomas by propranolol-loaded CD133 aptamers conjugated liposomes-in-microspheres

We previously developed propranolol-encapsulated liposomes-in-microspheres (PLIM) to realize the sustained propranolol release for the treatment of hemangiomas. However, the liposomes released from the microspheres still lacked specificity for CD133-positive hemangioma-derived stem cells (HemSCs) which are considered to be the seeds of hemangiomas. Therefore, we hereby encapsulated propranolol-loaded CD133 aptamers conjugated liposomes in poly(lactic-co-glycolic acid (PLGA) microspheres to develop propranolol-loaded CD133 aptamers conjugated liposomes-in-microspheres (PCLIM), to realize the aim of the sustained and targeted therapy of hemangiomas. The evaluation of the release of propranolol from PCLIM was carried out, and the cytotoxic effect and angiogenic growth factor expression inhibitory ability of PCLIM were performed in HemSCs. The in vivo hemangioma inhibitory ability of PCLIM was also investigated in nude mice with subcutaneous human hemangiomas. PCLIM possessed a desired size of 29.2 μm, drug encapsulation efficiency (25.3%), and a prolonged drug release for 40 days. Importantly, PCLIM could inhibit HemSCs proliferation and the protein expression of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor-A (VEGF) in HemSCs to a greater extent compared with PLIM. In nude mice bearing hemangioma xenograft, PCLIM showed the best therapeutic efficacy towards hemangiomas, as reflected by remarkably decreased hemangioma volume, weight and microvessel density (MVD). Thus, our results demonstrated that PCLIM realized the sustained and targeted treatment of hemangiomas, resulting in remarkable inhibition of hemangiomas.

Insulin-like growth factor 2 promotes the adipogenesis of hemangioma-derived stem cells.

Infantile hemangioma (IH), which is the most common tumor in infants, is characterized by rapid proliferation followed by spontaneous regression into fibro-fatty tissue in childhood. However, its specific mechanism has not been clarified. Our previous studies showed that insulin-like growth factor 2 (IGF-2) is increased in the proliferative phase of IH, which is deemed to form from hemangioma-derived stem cells (HemSC). However, it remains unclear whether IGF-2 can promote the adipogenic differentiation of HemSCs and the signaling mechanisms involved require further elucidation. In the present study, CCK-8 assay was used to detect the effect of different concentrations of IGF-2 on the proliferation of HemSCs. Immunohistochemistry was applied to observe the expression of IGF-2 and its receptors in cells. Oil red o-staining of adipogenesis was conducted after cells recevied no treatment or were induced with IGF-2 or IGF-2 plus OSI-906 for 10 days. Cells were cultured in EGM-2/FBS-10% alone or containing IGF-2, IGF-2 plus OSI-906 or IGF-2 plus LY294002 and the protein expression of C/EBPα, C/EBPβ, PPARγ, adiponectin, p-AKT and total AKT was determined using western blot analysis. In another experiment, cells were treated with 25, 50 or 100 μM propranolol, or vehicle. C/EBPα, C/EBPβ, PPARγ and IGF-2 were analyzed using western blot analysis or reverse transcription-quantitative polymerase chain reaction. Results indicated that IGF-2 significantly promoted the cell proliferation and lipid accumulation of HemSCs. The expression of phosphorylated AKT (p-AKT), C/EBPα, C/EBPβ, PPARγ and adiponectin was increased in IGF-2-treated HemSCs culture, whereas these changes were repressed by the inhibition of either the IGF-1 receptor (IGF-1R) or phosphoinositide 3-kinase (PI3K). Our previous research showed that propranolol accelerated adipogenesis in HemSCs and induced the upregulation of IGF-2. The results of the present study indicate that IGF-2 is able to accelerate adipogenesis, and the propranolol-induced promotion of dysregulated adipogenesis may be mediated by the IGF-2 via IGF-1R and PI3K pathways.

Estrogen-mediated hemangioma-derived stem cells through estrogen receptor-α for infantile hemangioma.

BackgroundInfantile hemangiomas (IHs) are the most common benign vascular tumor of infancy. They occur more frequently in female infants. The cause of hemangioma is currently unknown; however, current studies suggested the importance of estrogen (E2) signaling in hemangioma proliferation.MethodsHemangioma-derived stem cells (HemSCs) were cultured with estrogen for 48–72 h; the cell viability and proliferation were evaluated with the messenger RNA (mRNA) and protein expression levels of fibroblast growth factor 2 (FGF2), vascular endothelial growth factor-A (VEGF-A) and estrogen receptor-α (ER-α), by application of several in vitro assays, such as methyl thiazolyl tetrazolium (MTT), reverse transcriptase–polymerase chain reaction (RT-PCR), real-time PCR, enzyme-linked immunosorbent assay (ELISA) and Western blotting. Also, the cell population’s response to external estrogen was investigated by in vivo experiments. HemSCs and human umbilical vein endothelial cells (HUVECs) were mixed and injected subcutaneously into 20 flank of BALB/c-nu mice, which were randomly divided into 5 groups based on different E2 treatment doses (0, 0.01, 0.1 and 1 mg, respectively), 0.1 mg dimethyl sulfoxide (DMSO) as control. Each group of mice were treated intramuscularly every week, then 2 and 4 weeks later, the subcutaneous implants were harvested and evaluated the tumor tissues with microvessel density (MVD) assay and immunohistochemistry.ResultsThe study demonstrated that application of E2 increased the expression of FGF2, VEGF-A, and ER-α in HemSCs with the optimal concentration from 10−9 to 10−5 M. Two-week treatment of E2 promoted expression of VEGF-A and FGF2 in HemSCs culture. Morphological, histological and immunohistological improvements were observed in vivo using murine IH model in which HemSCs and HUVECs were implanted into BALB/c-nu mice that were post-injected with E2. In the grafts, mean MVD was markedly increased.ConclusionThe results suggested that E2 promotes angiogenesis via combination with ER-α to up-regulate the expression of VEGF-A in HemSCs, promoting proliferation of IHs. These findings provide critical insight into the potential mechanisms of E2 action on IHs.

Infantile hemangioma-derived stem cells and endothelial cells are inhibited by class 3 semaphorins

Class 3 semaphorins were discovered as a family of axon guidance molecules, but are now known to be involved in diverse biologic processes. In this study, we investigated the anti-angiogenic potential of SEMA3E and SEMA3F (SEMA3E&F) in infantile hemangioma (IH). IH is a common vascular tumor that involves both vasculogenesis and angiogenesis. Our lab has identified and isolated hemangioma stem cells (HemSC), glucose transporter 1 positive (GLUT1+) endothelial cells (designated as GLUT1sel cells) based on anti-GLUT1 magnetic beads selection and GLUT1-negative endothelial cells (named HemEC). We have shown that these types of cells play important roles in hemangiogenesis. We report here that SEMA3E inhibited HemEC migration and proliferation while SEMA3F was able to suppress the migration and proliferation in all three types of cells. Confocal microscopy showed that stress fibers in HemEC were reduced by SEMA3E&F and that stress fibers in HemSC were decreased by SEMA3F, which led to cytoskeletal collapse and loss of cell motility in both cell types. Additionally, SEMA3E&F were able to inhibit vascular endothelial growth factor (VEGF)-induced sprouts in all three types of cells. Further, SEMA3E&F reduced the level of p-VEGFR2 and its downstream p-ERK in HemEC. These results demonstrate that SEMA3E&F inhibit IH cell proliferation and suppress the angiogenic activities of migration and sprout formation. SEMA3E&F may have therapeutic potential to treat or prevent growth of highly proliferative IH.

β1-Adrenoceptor mRNA level reveals distinctions between infantile hemangioma and vascular malformations

Infantile hemangioma (IH) is the most frequent vascular tumor of early childhood. Recently, propranolol, a nonselective β1- and β2-adrenoceptor inhibitor, was introduced into the therapy of severe proliferating IH with excellent results. However, the underlying mechanism of action of propranolol is still unclear. We performed immunohistochemistry for cluster of differentiation 31 (CD31), D2-40, glucose transporter-1 (GLUT-1), and Ki67 in order to characterize 21 vascular anomalies (nine IH, seven venous malformations (VMs), and five lymphatic malformations (LMs)). Furthermore, we analyzed the expression of β1-, β2-, and β3-adrenoceptor mRNA in these specimens as well as in hemangioma-derived stem cells by quantitative real-time PCR (qPCR). We show that the expression of β1-adrenoceptor mRNA is 10.7-fold higher in IH independent of the proliferative or regressive phase as well as 2.5-fold higher in hemangioma-derived stem cells as compared with β2-adrenoceptor mRNA. In LM, the expression of β2-adrenoceptor mRNA was ninefold higher than that of β1-adrenoceptor mRNA. VM showed low expression levels of all β-adrenoceptor mRNAs, and β3-adrenoceptor mRNA was hardly detectable in any specimens examined. These results provide the first evidence of distinctions between IH and vascular malformations with regard to β-adrenoceptor subtype mRNA levels.

Intrinsic regulation of hemangioma involution by platelet-derived growth factor

Infantile hemangioma is a vascular tumor that exhibits a unique natural cycle of rapid growth followed by involution. Previously, we have shown that hemangiomas arise from CD133+ stem cells that differentiate into endothelial cells when implanted in immunodeficient mice. The same clonally expanded stem cells also produced adipocytes, thus recapitulating the involuting phase of hemangioma. In the present study, we have elucidated the intrinsic mechanisms of adipocyte differentiation using hemangioma-derived stem cells (hemSCs). We found that platelet-derived growth factor (PDGF) is elevated during the proliferating phase and may inhibit adipocyte differentiation. hemSCs expressed high levels of PDGF-B and showed sustained tyrosine phosphorylation of PDGF receptors under basal (unstimulated) conditions. Inhibition of PDGF receptor signaling caused enhanced adipogenesis in hemSCs. Furthermore, exposure of hemSCs to exogenous PDGF-BB reduced the fat content and the expression of adipocyte-specific transcription factors. We also show that these autogenous inhibitory effects are mediated by PDGF receptor-β signaling. In summary, this study identifies PDGF signaling as an intrinsic negative regulator of hemangioma involution and highlights the therapeutic potential of disrupting PDGF signaling for the treatment of hemangiomas.

Unusual Case of Hypothyroidism in an Infant With Hepatic Hemangioma

Unusual Case of Hypothyroidism in an Infant With Hepatic Hemangioma

Corticosteroid Suppression of Vascular Endothelial Growth Factor and Recurrence of Chronic Subdural Hematoma

We read with interest the article by Berghauser et al1 in which the authors described that in surgical treatment of chronic subdural hematoma (CSDH) with burr hole craniostomy, a longer period of preoperative dexamethasone administration is associated with a lower recurrence rate of CSDH and that dexamethasone administration seems to be unrelated to the higher incidence of complications and treatment-related deaths compared with the current literature. However, the authors mentioned that the mechanism of action of dexamethasone in CSDH has not been fully clarified. We wish to provide further comments on the issue of the effect of preoperative dexamethasone administration on CSDH recurrence. The involvement of vascular endothelial growth factor (VEGF), a potent inducer of angiogenesis and vascular permeability, in the pathogenesis of CSDH and the mechanism of recurrent CSDH has been reported.2-4 Weigel et al2 reported that 5% (4 of 81) of the patients with angiotensin-converting enzyme (ACE) inhibition experienced recurrence as opposed to 18% (42 of 229) of patients without ACE inhibition (P = .00345) and that VEGF content was significantly lower in the hematomas of patients with ACE inhibition than in those without. Greenberger et al5 reported that systemic treatment with dexamethasone led to dose-dependent inhibition of vasculogenesis in an in vivo model of infantile hemangioma and that dexamethasone suppressed VEGF production in hemangioma-derived stem cells in vitro. On the basis of these reports, we consider that the effect of preoperative dexamethasone administration on the recurrence of CSDH might be dependent on the corticosteroid suppression of VEGF. Additionally, Funai et al3 recently reported that phosphatidylinositol 3-kinase/Akt signaling is activated in CSDH outer membranes and that the phosphatidylinositol 3-kinase/Akt pathway might be activated by VEGF in outer membranes. A previous study by Nanko et al4 also revealed that VEGF expression in the outer membrane of 30 patients with CSDH was significantly correlated with VEGF concentration in the hematoma (r[s] = .654, P = .0013) and that VEGF concentration in layered hematomas, which have an intrahematoma membranous structure, was significantly higher than in nonlayered hematomas (P < .01), suggesting that the high concentration of VEGF in the hematoma can originate from the hematoma membrane. We previously reported recurrence rates in 64 consecutive patients after CSDH evacuation.6 Recurrence was noted in 7 of the 64 patients (10.9%) after burr-hole craniostomy with drainage, and layered hematoma was seen in 3 of the 7 recurrent cases (42.9%). Therefore, we consider that preoperative dexamethasone administration might be effective in the prevention of recurrent CSDH, especially in the case of layered-type CSDH. Further investigations on the relationship between preoperative dexamethasone administration and VEGF concentration in the hematoma and the correlation of preoperative dexamethasone administration and preoperative radiological findings of hematomas with CSDH recurrence will provide additional insights into the recurrence of CSDH after preoperative dexamethasone administration. Disclosure The authors have no personal financial or institutional interest in any of the drugs, materials, or devices described in this article.

Targeting NF-κB in infantile hemangioma-derived stem cells reduces VEGF-A expression

infantile hemangioma (IH) is a most common tumor of infancy. Using infantile hemangioma-derived stem cells (HemSCs), we recently demonstrated that corticosteroids suppress the expression of VEGF-A, monocyte chemoattractant protein-1 (MCP-1), urokinase plasminogen activator receptor (uPAR), and interleukin-6 (IL-6); each of these are known targets of the transcription factor nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB). In the present study, we examined the expression of these NF-κB target genes in IH tissue specimens and the effect of NF-κB regulation on the expression of pro-angiogenic cytokines, and in particular VEGF-A, in HemSCs. RNA extracted from IH tissue and hemangioma-derived stem cells (HemSCs) was used to analyze NF-κB target gene expression by reverse transcription-quantitative PCR (RT-qPCR). The effects of NF-κB blockade were examined in HemSCs. Immunostaining, immunoblotting and ELISA were used to assess protein expression. MCP-1, uPAR, and IL-6 were found to be differentially expressed in proliferating versus involuting IH. Corticosteroids suppressed NF-κB activity of HemSCs. Velcade (Bortezomib), a proteosome inhibitor that can indirectly inhibit NF-κB, impaired HemSCs viability and expression of pro-angiogenic factors. Furthermore, specific inhibition of NF-κB resulted in suppression of VEGF-A. we demonstrate expression of NF-κB target genes in proliferating IH. In addition, we show that the expression of several pro-angiogenic factors in HemSCs, and in particular VEGF-A, is regulated by NF-B activity.

Corticosteroid Suppression of VEGF-A in Infantile Hemangioma-Derived Stem Cells

Corticosteroids are commonly used to treat infantile hemangioma, but the mechanism of action of this therapy is unknown. We investigated the effect of corticosteroids in a previously described in vivo model of infantile hemangioma and in cultured hemangioma-derived cells. We tested hemangioma-derived stem cells for vasculogenic activity in vivo after implantation into immune-deficient (nude) mice. We studied dexamethasone treatment of both the cells before implantation and the mice after implantation. We also tested hemangioma-derived stem cells for expression of vascular endothelial growth factor A (VEGF-A) in vitro and studied the inhibition of VEGF-A expression, using short hairpin RNA (shRNA) in vivo and in vitro. Systemic treatment with dexamethasone led to dose-dependent inhibition of tumor vasculogenesis in the murine model. Pretreatment of hemangioma-derived stem cells in vitro before implantation also inhibited vasculogenesis. Dexamethasone suppressed VEGF-A production by hemangioma-derived stem cells in vitro but not by hemangioma-derived endothelial cells or human umbilical-vein endothelial cells. Silencing VEGF-A in hemangioma-derived stem cells reduced vasculogenesis in vivo. VEGF-A was detected in hemangioma specimens in the proliferating phase but not in the involuting phase and was shown by immunostaining to reside outside of vessels. Corticosteroid treatment suppressed other proangiogenic factors in hemangioma-derived stem cells, including urokinase plasminogen activator receptor, interleukin-6, monocyte chemoattractant protein 1, and matrix metalloproteinase 1. In a murine model, dexamethasone inhibited the vasculogenic potential of stem cells derived from human infantile hemangioma. The corticosteroid also inhibited the expression of VEGF-A by hemangioma-derived stem cells, and silencing of VEGF-A expression in these cells inhibited vasculogenesis in vivo.

A switch in Notch gene expression parallels stem cell to endothelial transition in infantile hemangioma

Infantile hemangioma (IH) is the most common benign tumor of infancy, yet its pathogenesis is poorly understood. Notch family members are known to play a role in vascular development during embryogenesis and postnatal tumor angiogenesis, yet the role of Notch signaling in the pathogenesis of IH has not been investigated. This study aims to survey Notch expression in IH. RNA from resected hemangioma tissue and hemangioma-derived stem cells (HemSCs) and endothelial cells (HemECs) was used for gene expression analyses by real-time PCR. Results were confirmed with immunofluorescence for protein expression in tissue. Real-time PCR showed that Notch family gene expression in IH is distinct from placenta and skin. Notch3 is expressed in HemSCs, but not in HemECs, indicating Notch3 is downregulated as HemSCs differentiate into HemECs. Moreover, expression of endothelial-associated Notch proteins, Notch1, Notch4, and Jagged-1 are increased in involuting hemangiomas and HemECs, suggesting that as hemangioma progresses toward involution, it acquires more differentiated endothelium. A subset of cells stained double positive for Notch3 and CD31, pointing to a potential intermediate between the HemSC cellular differentiation into HemEC. HemSCs have distinct Notch expression patterns from differentiated HemECs and from normal human endothelial cells. Notch3 is expressed in HemSCs, while Notch1, Notch4, and Jagged-1 have higher expression levels in HemECs. Notch3 was localized to the interstitial cells outside of the nascent vascular channels in proliferating IH tissue sections, but became more apparent in the perivascular cells in involuting IH. In summary, the pattern of Notch gene expression mirrors the progression from immature cells to endothelial-lined vascular channels (i.e., endothelial differentiation) that characterizes the growth and involution of IH.

Corticosteroid Suppression in Infant Hemangioma-Derived Stem Cells

Infantile hemangioma is the most common tumor of infancy. Although most can be observed for spontaneous involution, approximately 10% require intervention because of ulceration, disfigurement, or obstructed vision, airway, or other vital function. Corticosteroids (systemic or intralesional) have been the standard therapy for problematic hemangiomas since the 1960s, but how they stabilize proliferation and accelerate regression is not known. When injected into nude mice, …

A possible mechanism of spontaneous involution of infantile hemangioma

Infantile hemangiomas are common vascular tumours which exhibit a rapid proliferating phase followed by spontaneously involuting for a long time. The formation and development mechanisms are not clear yet. Recent studies show that hemangioma-derived stem cells have multipotential differentiation abilities, including endothelial and mesenchymal differentiation. In addition, mesenchymal stem cell has the capability of inducing endothelial cell apoptosis, differentiating into adipocytes and triggering the involution of hemangiomas. Thus we hypothesize that mesenchymal stem cell may be the source of spontaneously regression of hemangiomas. Further investigations may be needed to develop potential therapeutic implications of mesenchymal stem cell in treating hemangiomas.