2015年4月10日訊 /生物谷BIOON/ --近日,國際學術期刊nature communication在線發表了美國科學家的一項最新研究進展,他們對109名胰腺導管腺癌(PDA)病人進行了全外顯子測序,發現了PDA中的基因突變多樣性,並且為發現PDA治療靶點提供了重要信息。
胰腺導管腺癌是一種預後效果非常差的惡性疾病,需要深入了解該疾病的病因並開發靶向治療策略。由於PDA腫瘤中存在大量基質細胞和炎症細胞,因此對來自於病人的腫瘤樣本進行腫瘤細胞測序存在很大障礙,難以獲得高質量數據。
在該項研究中,研究人員為方便檢測基因突變,同時移除非腫瘤性組織的汙染,他們利用顯微切割的方法將癌症患者的腫瘤組織進行了異種移植並建立了細胞系。隨後對109例進行過顯微切割的PDA病例進行了全外顯子測序,經過顯微切割操作後,腫瘤細胞得到富集並增強了對基因突變的檢測。
研究人員通過分析發現導致PDA發生的病因事件與腫瘤突變譜具有明顯相關性。拷貝數的改變會靶向多個腫瘤抑制/致癌基因位點,但是唯獨MYC基因的擴增與PDA惡性程度和腺體亞型相關。他們還發現了PDA疾病中的多個新的突變基因,並且部分基因對於該疾病的預後效果具有重要影響。同時,在超過90%的病例中都可觀察到KRAS突變但編碼Q61密碼子的基因與病人存活率增加具有特異性關聯。癌基因BRAF突變與KRAS互相排斥,並且與vemurafenib治療PDA模型的敏感性相關。研究人員還觀察到Wnt信號通路,染色質重塑,Hedgehog通路,DNA修復和細胞周期進程中的相關基因都會發生高頻率突變。
總的來說,這些結果描述了PDA疾病中新的基因多樣性,為確定影響該疾病預後的因素,開發治療方法提供了深入見解。(生物谷Bioon.com)
Whole-exome sequencing of pancreatic cancer defines genetic diversity and therapeutic targets
Agnieszka K. Witkiewicz,Elizabeth A. McMillan,Uthra Balaji,GuemHee Baek,Wan-Chi Lin,John Mansour,Mehri Mollaee,Kay-Uwe Wagner,Prasad Koduru,Adam Yopp,Michael A. Choti,Charles J. Yeo,Peter McCue,Michael A. White& Erik S. Knudsen
Pancreatic ductal adenocarcinoma (PDA) has a dismal prognosis and insights into both disease etiology and targeted intervention are needed. A total of 109 micro-dissected PDA cases were subjected to whole-exome sequencing. Microdissection enriches tumour cellularity and enhances mutation calling. Here we show that environmental stress and alterations in DNA repair genes associate with distinct mutation spectra. Copy number alterations target multiple tumour suppressive/oncogenic loci; however, amplification of MYC is uniquely associated with poor outcome and adenosquamous subtype. We identify multiple novel mutated genes in PDA, with select genes harbouring prognostic significance. RBM10 mutations associate with longer survival in spite of histological features of aggressive disease. KRAS mutations are observed in >90% of cases, but codon Q61 alleles are selectively associated with improved survival. Oncogenic BRAFmutations are mutually exclusive with KRAS and define sensitivity to vemurafenib in PDA models. High-frequency alterations in Wnt signalling, chromatin remodelling, Hedgehog signalling, DNA repair and cell cycle processes are observed. Together, these data delineate new genetic diversity of PDA and provide insights into prognostic determinants and therapeutic targets.