Division of Clinical Pathology, Department of General Pathology, School of Medicine, Second University of Naples, 80138 Naples, Italy.
Proc Natl Acad Sci U S A. 2010 Aug 10;107(32):14484-9. doi: 10.1073/pnas.1008256107. Epub 2010 Jul 26.
Tumor growth requires neoangiogenesis. VEGF is the most potent proangiogenic factor. Dysregulation of hypoxia-inducible factor (HIF) or cytokine stimuli such as those involving the chemokine receptor 4/stromal-derived cell factor 1 (CXCR4/SDF-1) axis are the major cause of ectopic overexpression of VEGF in tumors. Although the CXCR4/SDF-1 pathway is well characterized, the transcription factors executing the effector function of this signaling are poorly understood. The multifunctional Yin Yang 1 (YY1) protein is highly expressed in different types of cancers and may regulate some cancer-related genes. The network involving CXCR4/YY1 and neoangiogenesis could play a major role in cancer progression. In this study we have shown that YY1 forms an active complex with HIF-1alpha at VEGF gene promoters and increases VEGF transcription and expression observed by RT-PCR, ELISA, and Western blot using two different antibodies against VEGFB. Long-term treatment with T22 peptide (a CXCR4/SDF-1 inhibitor) and YY1 silencing can reduce in vivo systemic neoangiogenesis (P < 0.01 and P < 0.05 vs. control, respectively) during metastasis. Moreover, using an in vitro angiogenesis assay, we observed that YY1 silencing led to a 60% reduction in branches (P < 0.01) and tube length (P < 0.02) and a 75% reduction in tube area (P < 0.001) compared with control cells. A similar reduction was observed using T22 peptide. We demonstrated that T22 peptide determines YY1 cytoplasmic accumulation by reducing its phosphorylation via down-regulation of AKT, identifying a crosstalk mechanism involving CXCR4/YY1. Thus, YY1 may represent a crucial molecular target for antiangiogenic therapy during cancer progression.
肿瘤的生长需要新生血管生成。VEGF 是最有效的促血管生成因子。缺氧诱导因子（HIF）或细胞因子刺激（如涉及趋化因子受体 4/基质衍生细胞因子 1（CXCR4/SDF-1）轴的刺激）的失调是肿瘤中 VEGF 异位过表达的主要原因。虽然 CXCR4/SDF-1 途径已经得到很好的描述，但执行该信号转导效应功能的转录因子知之甚少。多功能 Yin Yang 1（YY1）蛋白在不同类型的癌症中高度表达，可能调节一些与癌症相关的基因。涉及 CXCR4/YY1 和新生血管形成的网络可能在癌症进展中起主要作用。在这项研究中，我们已经表明，YY1 在 VEGF 基因启动子上与 HIF-1alpha 形成一个活性复合物，并增加 VEGF 转录和表达，这可以通过使用两种针对 VEGFB 的不同抗体的 RT-PCR、ELISA 和 Western blot 观察到。使用 T22 肽（CXCR4/SDF-1 抑制剂）和 YY1 沉默的长期治疗可以减少体内系统性新生血管生成（分别与对照组相比，P < 0.01 和 P < 0.05）在转移过程中。此外，使用体外血管生成测定，我们观察到 YY1 沉默导致分支减少 60%（P < 0.01），管长减少 60%（P < 0.02），管面积减少 75%（P < 0.001）与对照细胞相比。使用 T22 肽观察到类似的减少。我们证明 T22 肽通过下调 AKT 来确定 YY1 的细胞质积累，从而确定了涉及 CXCR4/YY1 的串扰机制。因此，YY1 可能代表癌症进展期间抗血管生成治疗的关键分子靶标。
