2015年3月17日訊 /生物谷BIOON/——美國史丹福大學醫學院的研究人員最近表示,當白血病細胞在體內肆虐攻擊,解決方案可能是就讓它們發育成長。研究人員通過實驗室觀察發現了使危險白血病細胞成熟並轉身為無害的巨噬細胞的方法。研究結果在線發表在最新的PNAS上。
含有一個名為費城染色體(the Philadelphia chromosome)的突變的B細胞急性淋巴細胞白血病是一種極具侵略性的癌症,往往預後不良。研究人員一直試圖尋找潛在的治療方法。
Majeti博士和他的同事們從病人身上收集的白血病細胞,並試圖保持細胞在培養皿上存活下去。「我們給他們餵了各種可能的東西,來幫助他們生存下去。」Majeti博士表示。隨後他們發現有些白血病細胞在改變形狀和大小,變成巨噬細胞類似的樣子。他們確定了這一發現,卻不知原因,直到他們想起了一個古老的研究論文曾表明早期的小鼠B細胞祖細胞如果暴露於某些轉錄因子,可能被迫轉為巨噬細胞。研究人員隨即確認了骨髓分化促進細胞因子(myeloid differentiation-promoting cytokines)就是這個關鍵分子。轉化後的白血病細胞,在外觀上,基因表達上以及功能上都類似於正常的巨噬細胞。更重要的是,這些轉化的B細胞移植到免疫缺陷小鼠體內後,不會引起白血病!這直接證實了白血病細胞重新編程後,已經失去了它的致癌性,這無疑提示了白血病治療的一種新策略。
研究人員下一步將看看是否能找到一種藥物,可以誘發同樣的反應,並以此為基礎,用於治療白血病。其實曾有一些類似治療的先例:視黃酸是通常用於另一種稱為急性早幼粒細胞性白血病,它能把白血病細胞轉變為成熟的粒細胞。這種治療是之前唯一使癌細胞「成熟」的癌症治療方法。或許不久將來,我們能發現更多。(生物谷Bioon.com)
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doi: 10.1073/pnas.1413383112
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Reprogramming of primary human Philadelphia chromosome-positive B cell acute lymphoblastic leukemia cells into nonleukemic macrophages
James Scott McClellan, Christopher Dove, Andrew J. Gentles, Christine E. Ryan,and Ravindra Majeti
Abstract
BCR–ABL1+ precursor B-cell acute lymphoblastic leukemia (BCR–ABL1+ B-ALL) is an aggressive hematopoietic neoplasm characterized by a block in differentiation due in part to the somatic loss of transcription factors required for B-cell development. We hypothesized that overcoming this differentiation block by forcing cells to reprogram to the myeloid lineage would reduce the leukemogenicity of these cells. We found that primary human BCR–ABL1+ B-ALL cells could be induced to reprogram into macrophage-like cells by exposure to myeloid differentiation-promoting cytokines in vitro or by transient expression of the myeloid transcription factor C/EBPα or PU.1. The resultant cells were clonally related to the primary leukemic blasts but resembled normal macrophages in appearance, immunophenotype, gene expression, and function. Most importantly, these macrophage-like cells were unable to establish disease in xenograft hosts, indicating that lineage reprogramming eliminates the leukemogenicity of BCR–ABL1+ B-ALL cells, and suggesting a previously unidentified therapeutic strategy for this disease. Finally, we determined that myeloid reprogramming may occur to some degree in human patients by identifying primary CD14+ monocytes/macrophages in BCR–ABL1+ B-ALL patient samples that possess the BCR–ABL1+ translocation and clonally recombined VDJ regions.