Christopherson Richard I, Mactier Swetlana, Almazi Juhura G, Kohnke Philippa L, Best O Giles, Mulligan Stephen P
a School of Molecular Bioscience , University of Sydney , Sydney , NSW , Australia.
Nucleosides Nucleotides Nucleic Acids. 2014;33(4-6):375-83. doi: 10.1080/15257770.2013.863334.
Fludarabine (2-FaraAMP) is a purine analog that is effective against chronic lymphocytic leukemia (CLL) and non-Hodgkins lymphoma (NHL). For some cases of CLL, 2-FaraAMP as a single agent can clear the blood of leukemia cells, but leukemia stem cells usually remain protected in sanctuary sites. It is clear that 2-FaraAMP has multiple mechanisms of action that may collectively result in strand breaks in DNA, accumulation of phosphorylated p53 and apoptosis. We have demonstrated using the human Burkitt's lymphoma B-cell line, Raji, that p53, p63 and p73 all accumulate in the nucleus, following treatment of cells with fludarabine nucleoside (2-FaraA). In addition, phosphorylated p53 accumulates in the cytosol and at mitochondria. Using sophisticated methods of proteomic analysis with mass spectrometry, proteins that become differentially abundant after treatment of cells with 2-FaraA have been identified, providing considerable additional information about the cellular responses of B-lymphoid cancers to this purine analog. The levels of proteins involved in the unfolded protein response increase, indicating that endoplasmic reticulum stress is likely to be one mechanism for induction of apoptosis. The levels of a number of proteins found on the outer plasma membrane change on cells treated with 2-FaraA, suggesting that signaling from the B-cell antigen receptor (BCR) is stimulated, resulting in induction of apoptosis through the intrinsic pathway. Increased levels of the cell surface proteins, CD50, CD100 and ECE-1, would promote survival of these cells; the balance between these survival and death responses would determine the fate of the cell.
氟达拉滨（2-氟阿拉伯糖基腺嘌呤）是一种嘌呤类似物，对慢性淋巴细胞白血病（CLL）和非霍奇金淋巴瘤（NHL）有效。对于某些CLL病例，2-氟阿拉伯糖基腺嘌呤作为单一药物可清除血液中的白血病细胞，但白血病干细胞通常仍受庇护所部位的保护。很明显，2-氟阿拉伯糖基腺嘌呤具有多种作用机制，可能共同导致DNA链断裂、磷酸化p53的积累和细胞凋亡。我们使用人类伯基特淋巴瘤B细胞系Raji证明，在用氟达拉滨核苷（2-氟阿拉伯糖基腺嘌呤）处理细胞后，p53、p63和p73均在细胞核中积累。此外，磷酸化p53在细胞质和线粒体中积累。使用先进的质谱蛋白质组学分析方法，已鉴定出用2-氟阿拉伯糖基腺嘌呤处理细胞后丰度有差异的蛋白质，这为B淋巴细胞癌对这种嘌呤类似物的细胞反应提供了大量额外信息。参与未折叠蛋白反应的蛋白质水平增加，表明内质网应激可能是诱导细胞凋亡的一种机制。在用2-氟阿拉伯糖基腺嘌呤处理的细胞上，一些位于质膜外表面的蛋白质水平发生变化，这表明B细胞抗原受体（BCR）的信号传导受到刺激，导致通过内在途径诱导细胞凋亡。细胞表面蛋白CD50、CD100和ECE-1水平的增加会促进这些细胞的存活；这些存活和死亡反应之间的平衡将决定细胞的命运。
