Lovatt Charlotte, Williams Megan, Gibbs Alex, Mukhtar Abdullahi, Morgan Huw J, Lanfredini Simone, Olivero Carlotta, Spurlock Gill, Davies Sally, Philpott Charlotte, Tovell Hannah, Turnpenny Peter, Baban Dilair, Knight Sam, Brems Hilde, Sampson Julian R, Legius Eric, Upadhyaya Meena, Patel Girish K
European Cancer Stem Cell Research Institute Cardiff University Cardiff UK.
Division of Cancer and Genetics Institute of Medical Genetics Cardiff University Cardiff UK.
Skin Health Dis. 2024 Jun 24;4(5):e394. doi: 10.1002/ski2.394. eCollection 2024 Oct.
RASopathies, which include neurofibromatosis type 1 (NF1), are defined by Ras/mitogen-activated protein kinase (Ras/MAPK) pathway activation. They represent a group of clinically related disorders often characterised by multiple Café au Lait Macules (CALMs).
To determine, using in depth transcriptomic analysis of NF1 melanocytes from CALM and unaffected skin, (1) the gene(s) responsible for melanocyte proliferation and migration, and (2) the activated signalling pathway(s) in NF1 melanoma.
Classical NF1 ( = 2, who develop tumours) and 3bp deletion NF1 (p. Met992del, who do not develop tumours) ( = 3) patients underwent skin biopsies from CALM and unaffected skin. Melanocytes were isolated and propagated, with five replicates from each tissue sample. DNA and RNA were extracted for mutational analysis and transcriptomic profiling with six replicates per sample. Mechanistic determination was undertaken using melanocyte and melanoma cell lines.
All CALMs in NF1 were associated with biallelic loss, resulting in amplification of Ras/MAPK and Wnt pathway signalling. CALMs were also associated with reduced gene expression (and pigment epithelium-derived factor (PEDF) levels, the reciprocal protein), a known downstream target of the master regulator of melanocyte differentiation microphthalmia-associated transcription factor (MITF), leading to increased melanocyte proliferation, migration and invasion. In classical NF1 and melanoma, but not 3bp deletion NF1, there was also activation of the PI3K/AKT pathway. Pigment epithelium-derived factor was found to reduce cell proliferation and invasion of NF1 melanoma.
Melanocyte proliferation and migration leading to CALMs in NF1 arises from biallelic loss, resulting in RAS/MAPK pathway activation, and reduced expression of the tumour suppressor PEDF. Activation of the PI3K/AKT pathway in classical NF1 and NF1 melanoma may facilitate tumour growth.
包括1型神经纤维瘤病（NF1）在内的RAS病由Ras/丝裂原活化蛋白激酶（Ras/MAPK）信号通路激活所定义。它们代表了一组临床相关疾病，通常以多发咖啡牛奶斑（CALMs）为特征。
通过对来自CALM和未受影响皮肤的NF1黑素细胞进行深度转录组分析，确定（1）负责黑素细胞增殖和迁移的基因，以及（2）NF1黑色素瘤中激活的信号通路。
经典NF1患者（n = 2，发生肿瘤）和3bp缺失NF1患者（p.Met992del，未发生肿瘤）（n = 3）接受了来自CALM和未受影响皮肤的皮肤活检。分离并培养黑素细胞，每个组织样本进行五次重复。提取DNA和RNA用于突变分析和转录组分析，每个样本进行六次重复。使用黑素细胞和黑色素瘤细胞系进行机制研究。
NF1中的所有CALMs均与双等位基因NF1缺失相关，导致Ras/MAPK和Wnt信号通路扩增。CALMs还与小眼相关转录因子（MITF）（黑素细胞分化主调节因子的已知下游靶点）基因表达降低以及色素上皮衍生因子（PEDF）水平降低（相互作用蛋白）相关，导致黑素细胞增殖、迁移和侵袭增加。在经典NF1和黑色素瘤中，但在3bp缺失NF1中未发现PI3K/AKT信号通路激活。发现色素上皮衍生因子可减少NF1黑色素瘤的细胞增殖和侵袭。
NF1中导致CALMs的黑素细胞增殖和迁移源于双等位基因NF1缺失，导致RAS/MAPK信号通路激活以及肿瘤抑制因子PEDF表达降低。经典NF1和NF1黑色素瘤中PI3K/AKT信号通路的激活可能促进肿瘤生长。
