Expression of HES and HEY genes in infantile hemangiomas

Abstract

BackgroundInfantile hemangiomas (IHs) are the most common benign tumor of infancy, yet their pathogenesis is poorly understood. IHs are believed to originate from a progenitor cell, the hemangioma stem cell (HemSC). Recent studies by our group showed that NOTCH proteins and NOTCH ligands are expressed in hemangiomas, indicating Notch signaling may be active in IHs. We sought to investigate downstream activation of Notch signaling in hemangioma cells by evaluating the expression of the basic HLH family proteins, HES/HEY, in IHs.Materials and MethodsHemSCs and hemangioma endothelial cells (HemECs) are isolated from freshly resected hemangioma specimens. Quantitative RT-PCR was performed to probe for relative gene transcript levels (normalized to beta-actin). Immunofluorescence was performed to evaluate protein expression. Co-localization studies were performed with CD31 (endothelial cells) and NOTCH3 (peri-vascular, non-endothelial cells). HemSCs were treated with the gamma secretase inhibitor (GSI) Compound E, and gene transcript levels were quantified with real-time PCR.ResultsHEY1, HEYL, and HES1 are highly expressed in HemSCs, while HEY2 is highly expressed in HemECs. Protein expression evaluation by immunofluorescence confirms that HEY2 is expressed by HemECs (CD31+ cells), while HEY1, HEYL, and HES1 are more widely expressed and mostly expressed by perivascular cells of hemangiomas. Inhibition of Notch signaling by addition of GSI resulted in down-regulation of HES/HEY genes.ConclusionsHES/HEY genes are expressed in IHs in cell type specific patterns; HEY2 is expressed in HemECs and HEY1, HEYL, HES1 are expressed in HemSCs. This pattern suggests that HEY/HES genes act downstream of Notch receptors that function in distinct cell types of IHs. HES/HEY gene transcripts are decreased with the addition of a gamma-secretase inhibitor, Compound E, demonstrating that Notch signaling is active in infantile hemangioma cells.

Jagged1/Notch3 Signaling Modulates Hemangioma-Derived Pericyte Proliferation and Maturation

“…Jagged1 has been detected predominantly present in hemangioma ECs, whereas Notch3, Hes1 and HEYL are primarily expressed in hemangioma pericytes [15,17]. We examined the expression of Notch genes in Hem-pericytes in vitro (Fig.…”

“…Current data suggest that several Notch components are involved in the pathogenesis of IH [14][15][16][17]. Remarkably, recent studies have revealed that endothelial-derived Jagged1 can induce hemangioma-derived stem cells (HemSCs) to acquire a pericyte-like phenotype, which is a crucial step in the vasculogenesis of IH.…”

NOTCH3 regulates stem-to–mural cell differentiation in infantile hemangioma

“…Four mammalian NOTCH proteins (NOTCH1-4) are activated by 4 ligands (Delta-like ligands: DLL1 and -4 and JAG1 and -2) that have been extensively studied because of their essential roles in developmental (11) and pathological angiogenesis (12,13). We have previously published that NOTCH proteins are dynamically expressed and Notch signaling is activated in IH tissue and cells (9,14). NOTCH3 is expressed in perivascular cells in IH tissues, and HemSCs in vitro.…”

HEY2, a target of miR-137, indicates poor outcomes and promotes cell proliferation and migration in hepatocellular carcinoma

“…HEY2 was also involved in the postnatal retinal vascular remodeling [7], the differentiation of hair cell [8] and coronary vascular maturation [9]. Although the role of HEY2 in human cancer has not been identified, overexpression of HEY2 has been reported in prostate cancer [10], pancreatic ductal adenocarcinomas [11] and hemangioma [12]. Wittmann et al showed that HEY2 expression was deregulated in high-risk tumors and associated with tumor relapse in Wilms tumor [13].…”