Cohen P S, Chan J P, Lipkunskaya M, Biedler J L, Seeger R C
Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, CA.
Blood. 1994 Nov 15;84(10):3465-72.
During development, mice with mutations of stem cell factor (SCF) or its receptor c-kit exhibit defects in melanogenesis, as well as hematopoiesis and gonadogenesis. Because melanocytes derive from neural crest cells, the role of SCF and c-kit was investigated in the neural crest-derived childhood tumor neuroblastoma. Using reverse transcription-polymerase chain reaction analysis, simultaneous expression of steady-state mRNA for the SCF ligand and its receptor c-kit was found in 14 of 14 (100%) human neuroblastoma cell lines and clones and in 8 of 18 (45%) human neuroblastoma tumor samples. Functional blockade of c-kit receptors in the cell lines SK-N-BE(2) and SH-SY5Y using the mouse monoclonal anti-c-kit antibody SR-1 resulted in a significant decrease in cellular growth rate when measured by either 3H-thymidine incorporation or clonogenicity. In addition, higher levels of c-kit mRNA expression were associated with parental neuroblastoma cell lines and subclones with a neuronal (N) differentiation phenotype, whereas lower levels of c-kit mRNA were associated with neuroblastoma cell line subclones having a schwannian/glial/melanocytic pattern of differentiation. However, the differentiation phenotype of neuroblastoma cell lines was not directly altered when c-kit expression was blocked using the SR-1 antibody. In summary, these data indicate that c-kit receptor expression may play a significant role in the growth regulation of the two neuroblastoma cell lines examined and suggest that c-kit may also play a similar role in neuroblastoma growth regulation in vivo. Simultaneous expression of SCF and c-kit mRNA in both neuroblastoma cell lines and tumors implies that c-kit may act as part of an autocrine growth loop in conjunction with endogenous production of SCF in this disease.
在发育过程中，干细胞因子（SCF）或其受体c-kit发生突变的小鼠在黑色素生成、造血和性腺发育方面表现出缺陷。由于黑素细胞起源于神经嵴细胞，因此对SCF和c-kit在神经嵴衍生的儿童肿瘤神经母细胞瘤中的作用进行了研究。通过逆转录-聚合酶链反应分析发现，在14个（100%）人神经母细胞瘤细胞系和克隆以及18个（45%）人神经母细胞瘤肿瘤样本中的14个中，SCF配体及其受体c-kit的稳态mRNA同时表达。使用小鼠单克隆抗c-kit抗体SR-1对细胞系SK-N-BE(2)和SH-SY5Y中的c-kit受体进行功能阻断，通过3H-胸腺嘧啶核苷掺入或克隆形成能力测量，细胞生长速率显著降低。此外，较高水平的c-kit mRNA表达与具有神经元（N）分化表型的亲代神经母细胞瘤细胞系和亚克隆相关，而较低水平的c-kit mRNA与具有雪旺氏/神经胶质/黑素细胞分化模式的神经母细胞瘤细胞系亚克隆相关。然而，当使用SR-1抗体阻断c-kit表达时，神经母细胞瘤细胞系的分化表型并未直接改变。总之，这些数据表明c-kit受体表达可能在两种检测的神经母细胞瘤细胞系的生长调节中起重要作用，并提示c-kit在体内神经母细胞瘤生长调节中可能也起类似作用。神经母细胞瘤细胞系和肿瘤中SCF和c-kit mRNA的同时表达意味着c-kit可能与该疾病中SCF的内源性产生一起作为自分泌生长环的一部分发挥作用。
