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 anti­tumor 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 hemangioma­derived 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 pingyangmycin­treated HemECs exhibited typical apoptotic characteristics, including chromatin condensation and the formation of apoptotic bodies. Annexin­V staining demonstrated that pingyangmycin caused a significant and dose­dependent induction of apoptosis in the HemECs. In the pingyangmycin­treated HemECs, 4,752 genes demonstrated at least 2­fold expression changes at the mRNA level. Quantitative polymerase chain reaction confirmed that pingyangmycin significantly upregulated the expression of p53, p53­induced 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 pro­apoptotic activity of pingyangmycin against infantile hemangiomas involves p53 pathway activation.

Induction of apoptosis in infantile hemangioma endothelial cells by propranolol.

Propranolol, a non-selective ß-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.

Proteomic analysis of mitochondria from infantile hemangioma endothelial cells treated with sodium morrhuate and its liposomal formulation.

Hemangioma is the most common benign tumor of infancy. The aim of this study is to evaluate the biological effects of sodium morrhuate (SM) and its liposomal formulation on infantile hemangioma endothelial cells (IHECs). Morphological analysis revealed that exposure to liposomal sodium morrhuate (LSM) preferentially caused apoptotic death in IHECs, manifested as shrunken configuration and formation of apoptotic bodies. In contrast, necrotic death was prominent in IHECs treated with an equal concentration of SM. By means of proteomic analysis and confirmation experiments, we revealed that the apoptosis-inducing effects of LSM were associated with an upregulation of a set of genes involved in mitochondrial death pathway, including apoptosis-inducing factor, cytochrome c1, caspase-8, and lamin B1. In conclusion, our data highlight the proapoptotic activity of LSM in IHECs through the mitochondrial apoptotic pathway and may provide a promising avenue to treat hemangiomas of infancy.