Tomeczkowski J, Beilken A, Frick D, Wieland B, König A, Falk M H, Reiter A, Welte K, Sykora K W
Department of Pediatric Hematology and Oncology, Medical School Hannover, Germany.
Blood. 1995 Aug 15;86(4):1469-80.
The cytokine stem cell factor (SCF) synergizes with interleukin-7 (IL-7) to enhance the proliferation of pre-B cells. To examine the role of SCF and its receptor, c-kit, in the pathogenesis of pediatric Burkitt's lymphomas (BL), we investigated the expression of SCF and c-kit in BL cells and the mitogenic activity of SCF on BL cells. A panel of 13 BL cell lines and 7 fresh biopsy tumors was investigated. BL cells were stimulated either by Epstein-Barr virus (EBV) infection or by different reagents and cytokines, and expression of SCF and c-kit was studied on the mRNA level by Northern blot analysis and reverse-transcriptase polymerase chain reaction (RT-PCR), followed by Southern blotting. c-kit expression was also studied by fluorescence-activated cell sorting and by crosslinking of digoxigenin-labeled recombinant human SCF to the cell surface. Proliferation of BL cell lines was measured by 3H-thymidine incorporation. Low-level expression of c-kit mRNA was detected in 2 of 13 unstimulated BL cell lines and in 1 fresh BL tumor. One cell line showed upregulation of c-kit mRNA with A23187 and downregulation with phorbol myristate acetate. Neither c-kit nor SCF could be detected in any other cell line under any condition of stimulation as analyzed by Northern blot analysis, RT-PCR followed by Southern blot analysis, crosslinking, and immunofluorescence. No response to SCF was seen in 3H-thymidine incorporation assays. We conclude that most BL cells express neither SCF nor c-kit and that the low-level expression of c-kit in some BL cells most likely has no biologic significance.
细胞因子干细胞因子（SCF）与白细胞介素-7（IL-7）协同作用，增强前B细胞的增殖。为了研究SCF及其受体c-kit在儿童伯基特淋巴瘤（BL）发病机制中的作用，我们调查了BL细胞中SCF和c-kit的表达以及SCF对BL细胞的促有丝分裂活性。研究了一组13个BL细胞系和7个新鲜活检肿瘤。通过爱泼斯坦-巴尔病毒（EBV）感染或不同试剂及细胞因子刺激BL细胞，采用Northern印迹分析和逆转录聚合酶链反应（RT-PCR），随后进行Southern印迹，在mRNA水平研究SCF和c-kit的表达。还通过荧光激活细胞分选以及将地高辛标记的重组人SCF交联到细胞表面来研究c-kit的表达。通过3H-胸苷掺入法测量BL细胞系的增殖。在13个未刺激的BL细胞系中的2个以及1个新鲜BL肿瘤中检测到c-kit mRNA的低水平表达。一个细胞系在A23187作用下c-kit mRNA上调，在佛波酯肉豆蔻酸酯作用下下调。通过Northern印迹分析、RT-PCR随后进行Southern印迹分析、交联和免疫荧光分析，在任何刺激条件下的任何其他细胞系中均未检测到c-kit或SCF。在3H-胸苷掺入试验中未观察到对SCF的反应。我们得出结论，大多数BL细胞既不表达SCF也不表达c-kit，并且某些BL细胞中c-kit的低水平表达很可能没有生物学意义。
