Beck D, Gross N, Brognara C B, Perruisseau G
Research Laboratory, University Hospital, Lausanne, Switzerland.
Blood. 1995 Oct 15;86(8):3132-8.
Bone marrow (BM) is a frequent site of metastasis in children with neuroblastoma (NB). Nonhematopoietic cell lines of the same neuroectodermal origin produce both stem cell factor (SCF) and its receptor, the product of the c-kit protooncogene (c-kit). Because recombinant SCF is likely to be soon clinically tested to accelerate BM recovery after high-dose chemotherapy, a treatment administered to children with disseminated NB, we addressed the question of whether SCF/c-kit complex could play a role in the proliferation and metastasis of NB cells. Northern blot analysis showed SCF mRNA transcripts in 7 of 8 (88%) NB cell lines and c-kit in 1 (13%). Neither c-kit nor SCF could be detected by Western blotting in cell extracts or by surface immunofluorescence and flow cytometry. Soluble SCF protein was detected by enzyme immunoassay at low concentrations in the cell supernatants in the same 7 NB cell lines. Treatment of 4 NB cell lines by SCF +/- cytokines relevant to BM physiology did not induce c-kit antigenic expression or modulate 3H-thymidine uptake. Likewise, the latter was not changed by incubating the cells with anti-c-kit neutralizing antibodies. Immunohistochemical analysis showed weak diffuse or focal staining for SCF and c-kit in few primary or metastatic tumor samples, only once simultaneously. We conclude that NB cell lines usually produce low levels of soluble SCF but do not express c-kit and that both proteins are rarely detected in NB tumors. The SCF/c-kit complex appears to be unlikely to stimulate NB growth or metastasis; thus, recombinant SCF could be safely administered to children with NB.
骨髓（BM）是神经母细胞瘤（NB）患儿常见的转移部位。相同神经外胚层起源的非造血细胞系可产生干细胞因子（SCF）及其受体，即原癌基因c-kit的产物（c-kit）。由于重组SCF可能很快会进行临床试验，以加速大剂量化疗后骨髓的恢复，大剂量化疗是用于治疗播散性NB患儿的一种治疗方法，我们探讨了SCF/c-kit复合物是否可能在NB细胞的增殖和转移中发挥作用。Northern印迹分析显示，8个NB细胞系中有7个（88%）存在SCF mRNA转录本，1个（13%）存在c-kit。在细胞提取物中、通过表面免疫荧光和流式细胞术均未检测到c-kit或SCF的蛋白质印迹信号。在相同的7个NB细胞系的细胞上清液中，通过酶免疫测定法检测到低浓度的可溶性SCF蛋白。用与骨髓生理相关的SCF +/- 细胞因子处理4个NB细胞系，未诱导c-kit抗原表达或调节3H-胸腺嘧啶核苷摄取。同样，用抗c-kit中和抗体孵育细胞后，后者也未发生变化。免疫组织化学分析显示，在少数原发性或转移性肿瘤样本中，SCF和c-kit呈弱弥漫性或局灶性染色，仅在一次检测中同时出现。我们得出结论，NB细胞系通常产生低水平的可溶性SCF，但不表达c-kit，并且在NB肿瘤中很少同时检测到这两种蛋白。SCF/c-kit复合物似乎不太可能刺激NB生长或转移；因此，重组SCF可以安全地用于NB患儿。
