Department of Dermatology, Hunan Provincial People's Hospital (The First Affiliated Hospital of Hunan Normal University), Changsha, China.
Neoplasma. 2019 Mar 5;66(2):187-196. doi: 10.4149/neo_2018_180310N167. Epub 2018 Sep 16.
Melanoma is the main cause of death in patients with skin cancer. While the pathogenesis of cutaneous melanoma is poorly understood, increasing evidence shows that epidermal growth factor (EGF) may be involved. Herein, we tested the hypothesis that down-regulation of EGFL7 inhibits development and progression of human cutaneous melanoma (CM). Initially, we performed immunohistochemical analysis of EGFL7 in 130 specimens and the findings indicated that EGFL7 was highly expressed in CM. The expressions of EGFL7 and Notch signaling pathway-related genes in CM were then measured by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot assay. In order to assess biological functions of EGFL7 in CM we up-regulated or down-regulated endogenous EGFL7 using EGFL7-OE or shRNA against EGFL7 in the A375 CM cell line. To better understand the pivotal role of Notch signaling pathway in CM, we blocked this pathway in A375 cells by inhibitor treatment. Finally, tumor xenograft in nude mice was performed to test the in vivo tumorigenesis of the transfected A375 cells. While EGFL7 activated the Notch signaling pathway in CM, gain- and loss-of-function studies established that decreased EGFL7 inhibited cell proliferation and promoted apoptosis in A375 cells. Moreover, down-regulated EGFL7 suppressed in vivo tumorigenesis. Most importantly, we determined that down-regulating EGFL7 inhibited CM development by suppressing the Notch signaling pathway. The combined findings define potential roles of decreased EGFL7 as inhibitors of CM development by suppressing the Notch signaling pathway, and EGFL7 may therefore be a novel therapeutic target in cutaneous melanoma patients.
黑色素瘤是皮肤癌患者死亡的主要原因。虽然皮肤黑色素瘤的发病机制尚不清楚，但越来越多的证据表明表皮生长因子（EGF）可能与之相关。在此，我们检验了下调 EGFL7 可抑制人类皮肤黑色素瘤（CM）发展和进展的假说。最初，我们对 130 个标本进行了 EGFL7 的免疫组织化学分析，结果表明 EGFL7 在 CM 中高表达。然后通过逆转录定量聚合酶链反应（RT-qPCR）和 Western blot 检测 CM 中 EGFL7 和 Notch 信号通路相关基因的表达。为了评估 EGFL7 在 CM 中的生物学功能，我们使用 EGFL7-OE 或针对 EGFL7 的 shRNA 在 A375 CM 细胞系中上调或下调内源性 EGFL7。为了更好地理解 Notch 信号通路在 CM 中的关键作用，我们通过抑制剂处理阻断 A375 细胞中的该通路。最后，在裸鼠中进行肿瘤异种移植以测试转染的 A375 细胞的体内致瘤性。虽然 EGFL7 在 CM 中激活了 Notch 信号通路，但获得和丧失功能研究表明，降低 EGFL7 抑制了 A375 细胞的增殖并促进了细胞凋亡。此外，下调 EGFL7 抑制了体内肿瘤发生。最重要的是，我们确定下调 EGFL7 通过抑制 Notch 信号通路抑制 CM 的发展。综合研究结果定义了下调 EGFL7 通过抑制 Notch 信号通路作为 CM 抑制剂的潜在作用，因此 EGFL7 可能是皮肤黑色素瘤患者的一种新的治疗靶点。
