血管生态位和 VEGF-Nrp1 环路调节皮肤肿瘤的起始和干性。
A vascular niche and a VEGF-Nrp1 loop regulate the initiation and stemness of skin tumours.
机构信息
IRIBHM, Université Libre de Bruxelles, 808 route de Lennik, 1070 Brussels, Belgium.
出版信息
Nature. 2011 Oct 19;478(7369):399-403. doi: 10.1038/nature10525.
Angiogenesis is critical during tumour initiation and malignant progression. Different strategies aimed at blocking vascular endothelial growth factor (VEGF) and its receptors have been developed to inhibit angiogenesis in cancer patients. It has become increasingly clear that in addition to its effect on angiogenesis, other mechanisms including a direct effect of VEGF on tumour cells may account for the efficiency of VEGF-blockade therapies. Cancer stem cells (CSCs) have been described in various cancers including squamous tumours of the skin. Here we use a mouse model of skin tumours to investigate the impact of the vascular niche and VEGF signalling on controlling the stemness (the ability to self renew and differentiate) of squamous skin tumours during the early stages of tumour progression. We show that CSCs of skin papillomas are localized in a perivascular niche, in the immediate vicinity of endothelial cells. Furthermore, blocking VEGFR2 caused tumour regression not only by decreasing the microvascular density, but also by reducing CSC pool size and impairing CSC renewal properties. Conditional deletion of Vegfa in tumour epithelial cells caused tumours to regress, whereas VEGF overexpression by tumour epithelial cells accelerated tumour growth. In addition to its well-known effect on angiogenesis, VEGF affected skin tumour growth by promoting cancer stemness and symmetric CSC division, leading to CSC expansion. Moreover, deletion of neuropilin-1 (Nrp1), a VEGF co-receptor expressed in cutaneous CSCs, blocked VEGF's ability to promote cancer stemness and renewal. Our results identify a dual role for tumour-cell-derived VEGF in promoting cancer stemness: by stimulating angiogenesis in a paracrine manner, VEGF creates a perivascular niche for CSCs, and by directly affecting CSCs through Nrp1 in an autocrine loop, VEGF stimulates cancer stemness and renewal. Finally, deletion of Nrp1 in normal epidermis prevents skin tumour initiation. These results may have important implications for the prevention and treatment of skin cancers.
血管生成在肿瘤起始和恶性进展中至关重要。已经开发出了不同的策略来靶向血管内皮生长因子 (VEGF)及其受体,以抑制癌症患者的血管生成。越来越明显的是,除了对血管生成的影响外,VEGF 对肿瘤细胞的直接作用等其他机制也可能解释了 VEGF 阻断疗法的效率。癌症干细胞 (CSC) 已在包括皮肤鳞状肿瘤在内的各种癌症中得到描述。在这里,我们使用皮肤肿瘤的小鼠模型来研究血管生态位和 VEGF 信号对控制鳞状皮肤肿瘤在肿瘤进展早期的干性(自我更新和分化的能力)的影响。我们表明,皮肤乳头状瘤的 CSC 位于血管周围生态位中,紧邻内皮细胞。此外,阻断 VEGFR2 不仅通过降低微血管密度,而且通过减少 CSC 池大小和损害 CSC 更新特性来导致肿瘤消退。肿瘤上皮细胞中 Vegfa 的条件性缺失导致肿瘤消退,而肿瘤上皮细胞中 VEGF 的过表达则加速了肿瘤生长。除了对血管生成的已知影响外,VEGF 通过促进癌症干性和对称的 CSC 分裂来影响皮肤肿瘤的生长,从而导致 CSC 扩增。此外,表达于皮肤 CSC 中的 VEGF 共受体神经纤毛蛋白-1 (Nrp1) 的缺失阻断了 VEGF 促进癌症干性和更新的能力。我们的结果确定了肿瘤细胞衍生的 VEGF 在促进癌症干性方面的双重作用:通过旁分泌方式刺激血管生成,VEGF 为 CSC 创建了一个血管周围生态位,并且通过 Nrp1 在内分泌环中直接影响 CSC,VEGF 刺激癌症干性和更新。最后,正常表皮中 Nrp1 的缺失可防止皮肤肿瘤的发生。这些结果可能对皮肤癌的预防和治疗具有重要意义。