Fhit modulation of cell cycle progression and DNA damage response

FHIT对细胞周期进程和DMA损伤反应的调控 最近有人提出，在早期癌前病变中，DNA复制应激导致DNA 损伤反应(DDR)，导致生长停滞和细胞死亡。因此，在出现O-‘基因组之前 不稳定和转化，细胞激活DNA损伤反应网络，延缓或预防癌症； 损害检查点的突变，如ATM或ATR途径蛋白缺陷，ALCW逃逸 从检查站阻断，导致肿瘤进展。重要的是，对于这里提出的研究， 早期增生症在常见的脆性部位表现为等位基因失衡，尤其是FRA3B/FH1T基因座。 脆性位点LOH是在最大DDR期间的目标，可以被认为是 停滞不前的复制分叉“(Gorgoulis et at，Nature 434：907-913,2005)。 提出的这项研究是基于这样一种假设，即FHIT肿瘤抑制基因的丢失在 癌前过程，与DNA损伤反应(DDR)检查点的激活一致，影响 关键的细胞过程、细胞增殖、DNA损伤反应和凋亡，这些都可以改变tBalance 导致基因组不稳定和肿瘤进展。这一假设是基于初步数据证明的 FHIT缺陷细胞表现出细胞表达、细胞周期、DNA损伤反应和细胞凋亡的改变 相关蛋白和FHIT过表达调控Cyclin D1、Hus1、Chk1 Jind的表达 AKT/mTOR/Survivin。；； 这个项目的目标是了解这些通路FHIT调制的潜在机制 目标如下： 1)检测FHIT阴性细胞感染后FHIT下调Cyclin D1水平的机制 与AdenoFHIT和AdenoFHIT突变病毒。？ 2)确定FHIT调节Hus1、pChk1和CNA水平的机制 FHIT基因缺陷细胞中FHIT基因表达的损伤反应途径 3)检测FHIT在AdenoFHIT和AdenoFHIT突变体viius诱导细胞凋亡中的作用 FHIT缺陷细胞的感染和暴露在氧化应激条件下。 4)明确细胞周期、DDR和细胞凋亡相关蛋白表达的调控顺序 FHIT前后FHIT基因缺陷小鼠口腔和上消化道早期病变的变化 取而代之的是AdenoFHIT口服基因疗法。，

Fhit modulation of cell cycle progression and DMA damage response It has recently been proposedthat in early preneoplastic lesions, DNA replication stress leads tc the DNA Damage Response (DDR), which elicits growth arrest and cell death. Thus, before occurrence o-' genomic instability and transformation, cells activate DNA damage response networks that delay or prevent cancer; mutations that compromise the checkpoints, such as defects in Atm or Atr pathway proteins, allcw escape from the checkpoint block, leading to tumor progression. Importantly, for the research proposed here, the early hyperplasias showed allelic imbalance at common fragile sites, particularly the FRA3B/FH1T locus. "Fragile site LOH was targeted during the period of maximal DDR and may be considered a "signature" of stalled replicationforks" (Gorgoulis et at, Nature 434:907-913, 2005). The researchproposed is based on the hypothesis that loss of the Fhit tumor suppressorvery early in the preneoplastic process, coincident with activation of the DNA damage response (DDR) checkpoint, effects critical cellular processes, cell proliferation, DNA damage response and apoptosis, that can tip the tBalance toward genome instability and tumor progression. The hypothesis is based on preliminary data demonstrating that Fhit-deficient cells show altered expression of cell,cycle, DNA damage response andapoptosis associated proteins and that Fhit over-expression modulates expression of Cyclin D1, Hus1, Chk1 jind Akt/mTor/Survivin. ¿; ¿ The goals of this project are to understand the mechanisms underlying Fhit modulation of these pathways by the following aims: 1) Examine the mechanism of Fhit down-modulation of Cyclin D1 level after infection of Fhit negsitive cells with AdenoFHIT and AdenoFHIT mutant viruses. ¿ 2) Determine the mechanisms through which Fhit modulates" the level of Hus1, pChkl and the CNA damage response pathway by manipulation of Fhit .expression in Fhit-deficient cells. 3) Examine the role of Fhit in induction of apoptosis after AdenoFHIT and AdenoFHIT mutant viius infection of Fhit-deficient cells and exposure to oxidative stress conditions. 4) Define the sequenceof modulation of expression of cell.cycle, DDR and apoptosis associated proteins in early oral and upper gastrointestinal tract lesions of Fhit-deficient mice before and after FHIT replacement by AdenoFHIT oral gene therapy. ,