An experimental study on the therapy of infantile hemangioma with recombinant interferon γ

β-elemene affects angiogenesis of infantile hemangioma by regulating angiotensin-converting enzyme 2 and hypoxia-inducible factor-1 alpha

Infantile hemangioma (IH) is the most common benign vascular tumor resulting from the hyper-proliferation of vascular endothelial cells. In treatment of various tumors including IH, β-elemene, a compound extracted from Rhizoma zedoariae, has been reported to have anti-tumor effect. However, the underlying mechanisms of β-elemene in hemangioma have remained uninvestigated. In this presented study, functional analysis showed that low concentrations of β-elemene promoted the proliferation, migration and tube formation of human hemangioma endothelial cells (HemECs), while high concentrations of β-elemene produced inhibitory effects. Further, we also found that angiotensin-converting enzyme 2 (ACE2) expression was down-regulated at both mRNA and protein levels, while hypoxia-inducible factor-1 alpha (HIF-1-α) was up-regulated in infantile hemangiomas tissues and HemECs at both mRNA and protein levels. This result suggested that ACE2 and HIF-1-α play roles in IH. ACE2 expression was down-regulated with the treatment of β-elemene at different dosage point. Interestingly, the expression of Vascular endothelial growth factor-A (VEGFA) increased with treatment of low concentrations of β-elemene in HemECs, in contrary, the expression of VEGFA expression decreased with treatment of high concentrations of β-elemene. Moreover, if the concentration of β-elemene reached 40 μg/ml or higher, the expression of HIF-1-α decreased. Taken together, our data indicated that the different effects of β-elemene on the proliferation, migration and angiogenesis of hemangioma at different concentrations: The ACE2 signaling pathway dominates with treatment of low concentrations of β-elemene, stimulating the expression of downstream VEGFA to promote the angiogenesis of hemangioma; under the condition of high concentrations of β-elemene, the HIF-1-α signaling pathway inhibits the expression of VEGFA and further inhibits the angiogenesis of hemangioma.

Pingyangmycin stimulates apoptosis in human hemangioma-derived endothelial cells through activation of the p53 pathway

Pingyangmycin (also known as Bleomycin A5) is produced by Streptomyces verticillus var. pingyangensis n.sp., and has anti‑tumor activities against a variety of tumor cells. The aim of the present study was to determine the molecular mechanism(s) underlying the therapeutic effects of pingyangmycin against infantile hemangiomas. Human hemangioma‑derived endothelial cells (HemECs) were treated with pingyangmycin at varying concentrations (100, 200 or 300 µg/ml), and the morphological changes and apoptosis levels were assessed. The gene expression changes were determined by cDNA microarray technology. Transmission electron microscopy examination revealed that the pingyangmycin‑treated HemECs exhibited typical apoptotic characteristics, including chromatin condensation and the formation of apoptotic bodies. Annexin‑V staining demonstrated that pingyangmycin caused a significant and dose‑dependent induction of apoptosis in the HemECs. In the pingyangmycin‑treated HemECs, 4,752 genes demonstrated at least 2‑fold expression changes at the mRNA level. Quantitative polymerase chain reaction confirmed that pingyangmycin significantly upregulated the expression of p53, p53‑induced protein with death domain, Bax, p53 upregulated modulator of apoptosis and p53 inducible gene 3, and downregulated the expression of murine double minute 2. The data demonstrated that the pro‑apoptotic activity of pingyangmycin against infantile hemangiomas involves p53 pathway activation.

Induction of apoptosis in infantile hemangioma endothelial cells by propranolol

Propranolol, a non-selective β-blocker, is emerging as an effective treatment for complicated hemangiomas. The aim of this study was to investigate the molecular mechanism(s) underlying the therapeutic effects of propranolol against hemangiomas, using primary infantile hemangioma endothelial cells (IHECs). IHECs were treated with various concentrations of propranolol and morphological changes and apoptosis were assessed. Changes in the expression levels of apoptosis-related genes were examined. Annexin-V staining revealed that propranolol at 40, 50 and 60 μg/ml caused a concentration-dependent increase in the apoptosis of IHECs. Morphological analyses revealed that exposure to 50 μg/ml propranolol resulted in typical apoptotic changes, including shrinkage, the formation of apoptotic bodies and retention of plasma membrane integrity. Gene expression analyses revealed that propranolol treatment led to a marked increase in the expression of caspase-8, cytochrome c, apoptosis-inducing factor, caspase-3 and poly (ADP-ribose) polymerase 1, as well as a concomitant reduction in lamin B1 expression. Our data collectively demonstrate that propranolol induces apoptosis of IHECs through activation of the intrinsic and extrinsic apoptotic pathways, which represents an important mechanism for its therapeutic effects against infantile hemangiomas.

Scl gene construction, expression and effect on hemangioma

Hemangioma is a tumor that causes vascular endothelial cell hyperplasia, which commonly occur in newborns. Angiogenesis inhibitor targets the processes of angiogenesis, including the proliferation of vascular endothelial cells. A DNA sequence named Scl was designed, recombined into Pichia Pastoris, expressed by fermenting the engineered strain in a bioreactor, and purified the recombinant Scl by SP-sepharose fast flow. Scl can inhibit CAM angiogenesis. Only 1 μg of Scl significantly suppressed the growth of CAM blood vessel, similar to that of 25 μg of angiostatin. Scl showed a strong cytotoxicity on hemangioma cell (ATCC CRL No. 2587). After the drug acted for 24 h, the OD 570 measured value of the PBS control group averaged 1.873, whereas that of the Sc1 drug group was 0.692 (P < 0.01). Using the DeadEndTM Fluorometric TUNEL System, the detection results showed that 92 % of hemangioma cell apoptosis was observed in the Scl protein group, but only 1.3 % in the PBS control group (P < 0.01). After 2 weeks of treatment with the hemangioma model (cock's wattle) of the PBS group, 151 blood vessels with 100 views (40×) were obtained, whereas 250 in the PBS group (P < 0.01). During the two-week medication, the hemangioma model of the PBS group increased by 1.18 cm, whereas only 0.58 cm in the Scl drug group (P < 0.01).

Effects of propranolol on the proliferation and apoptosis of hemangioma-derived endothelial cells

BACKGROUND/PURPOSE

Propranolol, a non-selective beta-blocker, has recently been introduced as a novel treatment modality for proliferating hemangiomas. However, the mechanism of action of this therapy is unknown. In this study, we investigated propranolol in the etiology of hemangiomas that are associated with the proliferation and apoptosis of hemangioma-derived endothelial cells (HemECs).

METHODS

HemECs were isolated from freshly resected hemangioma specimens. We studied propranolol-treated HemECs in vitro. We measured the effect of propranolol on HemEC viability using the Cell Counting Kit-8 (CCK-8) assay and proliferation and apoptosis using a BrdU labeling assay, annexin-V-fluorescein isothiocyanate/propidium iodide flow cytometry, and Hoechst 33342 fluorescent staining. We explored the potential mechanisms of propranolol-induced HemEC dysfunction using western blot analysis, a caspase assay kit, and real-time quantitative PCR.

RESULTS

We observed that propranolol had inhibitory effects on the viability and proliferation of HemECs. HemEC apoptosis significantly increased with 100 μM propranolol treatment. Vascular endothelial growth factor (VEGF) expression was down-regulated by propranolol in a dose-dependent manner. We also demonstrated activation of the caspase cascade, including caspase-9 and caspase-3 of the intrinsic pathway, and an increased p53 gene expression and Bax/Bcl-xL ratio in HemECs treated with 100 μM propranolol.

CONCLUSIONS

We obtained novel data that suggests propranolol could inhibit HemEC proliferation and induce apoptosis. The effects were likely mediated through the suppression of VEGF expression, activation of caspase-9 and caspase-3, up-regulation of the pro-apoptotic genes p53 and Bax and down-regulation of the anti-apoptotic gene Bcl-xL.