2016年3月18日 訊 /生物谷BIOON/ - - TP53抑癌基因突變在人類癌症中廣泛存在,突變的p53會廢掉原本p53所具有的抑癌功能。突變型p53由兩步來在癌症中發生:首先是P53其中一個等位基因發生錯義突變,然後通過"雜合性缺失"造成另一個等位基因也被廢除從而成為突變型p53。
雖然,很多研究報導TP53的錯義突變促進腫瘤發生和進展,科學家開始普遍相信突變的p53獲得一系列新的促癌功能。但目前仍不清楚其它相關的抑癌基因的缺失是否同樣會促進腫瘤發生、進展產生類似的效果。
最近來自美國紀念斯隆凱特琳癌症中心的科研人員在Nature上發表了一篇文章。他們的研究工作表明,在小鼠模型上,對其染色體11B3(對應人染色體17p13.1)大約400萬鹼基區域進行雜合缺失後,科研人員發現將11B3這段區域缺失、並對小鼠Trp53缺失會對淋巴瘤和白血病的促進作用更顯著。
從結構上分析來看,對11B3的缺失,造成了對其它一些基因的聯合缺失,包括Eif5a和Alox15b(也稱為Alox8),這些基因的缺失與Trp53缺失協同產生了更嚴重的結果,增強Trp53促進腫瘤的生成。
他們的結果意味著,在人的染色體上高頻率出現17b區域缺失,體現了TP53基因缺失以及其它腫瘤相關的抑癌基因減少,共同造成一個更綜合性的促進腫瘤發生和進展的效果。(生物谷Bioon.com)
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doi:10.1038/nature17157
Deletions linked to TP53 loss drive cancer through p53-independent mechanisms
Yu Liu,Chong Chen,Zhengmin Xu,Claudio Scuoppo,Cory D. Rillahan, Jianjiong Gao,Barbara Spitzer,Benedikt Bosbach,Edward R. Kastenhuber,Timour Baslan,Sarah Ackermann,Lihua Cheng, Qingguo Wang,Ting Niu,Nikolaus Schultz,Ross L. Levine,Alea A. Mills & Scott W. Lowe
Mutations disabling the TP53 tumour suppressor gene represent the most frequent events in human cancer and typically occur through a two-hit mechanism involving a missense mutation in one allele and a 『loss of heterozygosity』 deletion encompassing the other. While TP53 missense mutations can also contribute gain-of-function activities that impact tumour progression, it remains unclear whether the deletion event, which frequently includes many genes, impacts tumorigenesis beyond TP53 loss alone. Here we show that somatic heterozygous deletion of mouse chromosome 11B3, a 4-megabase region syntenic to human 17p13.1, produces a greater effect on lymphoma and leukaemia development than Trp53 deletion. Mechanistically, the effect of 11B3 loss on tumorigenesis involves co-deleted genes such as Eif5a and Alox15b (also known as Alox8), the suppression of which cooperates with Trp53 loss to produce more aggressive disease. Our results imply that the selective advantage produced by human chromosome 17p deletion reflects the combined impact of TP53 loss and the reduced dosage of linked tumour suppressor genes.