AAV基因治療或可導致基因組整合
作者：
小柯機器人發布時間：2020/11/18 16:02:05
美國賓夕法尼亞大學Denise E. Sabatino研究組通過對A型血友病狗進行AAV基因治療的長期研究發現肝細胞的克隆擴增。2020年11月16日，國際知名學術期刊《自然—生物技術》在線發表了這一成果。
研究人員對九隻患有A型血友病的狗進行了腺相關病毒（AAV）基因治療，並隨訪了10年。使用表達犬因子VIII（AAV-cFVIII）的AAV8或AAV9載體可將FVIII缺乏症糾正至正常FVIII水平的1.9–11.3％。在其中兩隻狗中，FVIII活性水平在治療後約4年開始逐漸增加。沒有狗顯示出腫瘤或肝功能改變的跡象。
對來自六隻被治療狗的肝臟樣本中整合位點的分析確定了基因組DNA中1,741個獨特的AAV整合事件以及五隻狗中擴展的細胞克隆，其中近44％的整合涉及細胞生長。全部恢復的整合載體被部分刪除和/或重新排列。
這些數據表明，兩隻狗中FVIII蛋白表達的增加可能是由於攜帶整合載體的細胞克隆擴增。這些結果支持了針對血友病A的肝臟靶向AAV基因治療的臨床開發，同時強調了對潛在遺傳毒性進行長期監測的重要性。
附：英文原文
Title: A long-term study of AAV gene therapy in dogs with hemophilia A identifies clonal expansions of transduced liver cells
Author: Giang N. Nguyen, John K. Everett, Samita Kafle, Aoife M. Roche, Hayley E. Raymond, Jacob Leiby, Christian Wood, Charles-Antoine Assenmacher, Elizabeth P. Merricks, C. Tyler Long, Haig H. Kazazian, Timothy C. Nichols, Frederic D. Bushman, Denise E. Sabatino
Issue&Volume: 2020-11-16
Abstract: Nine dogs with hemophilia A were treated with adeno-associated viral (AAV) gene therapy and followed for up to 10 years. Administration of AAV8 or AAV9 vectors expressing canine factor VIII (AAV-cFVIII) corrected the FVIII deficiency to 1.9–11.3% of normal FVIII levels. In two of nine dogs, levels of FVIII activity increased gradually starting about 4 years after treatment. None of the dogs showed evidence of tumors or altered liver function. Analysis of integration sites in liver samples from six treated dogs identified 1,741 unique AAV integration events in genomic DNA and expanded cell clones in five dogs, with 44% of the integrations near genes involved in cell growth. All recovered integrated vectors were partially deleted and/or rearranged. Our data suggest that the increase in FVIII protein expression in two dogs may have been due to clonal expansion of cells harboring integrated vectors. These results support the clinical development of liver-directed AAV gene therapy for hemophilia A, while emphasizing the importance of long-term monitoring for potential genotoxicity.
DOI: 10.1038/s41587-020-0741-7
Source: https://www.nature.com/articles/s41587-020-0741-7