FHIT Gene Therapy in Cancer Prevention and Treatment

FHIT基因治疗在肿瘤防治中的应用我们已经研制出小鼠上消化道 口服N-亚硝基甲基苄胺（NMBA）或4-硝基喹啉1-氧化物（NQO）诱导的肿瘤模型 治疗野生型（WT）小鼠对这些致癌物不太敏感，但缺乏这两种致癌物的小鼠 Fhit或p53在暴露于NMBA或NQO时产生的肿瘤负荷比WT小鼠高10倍， 可预测的时间表。小鼠前胃肿瘤负荷通过FHIT治疗早期显著降低 （肿瘤预防）或晚期（肿瘤消退），以及肺癌和宫颈癌 研究正在进行中。对小鼠临床前模型的一个警告是， 表现出比人类更少的遗传复杂性和异质性，因此人类癌症可能是 对FHIT基因治疗的反应更低。拟议的研究旨在通过测试FHIT来解决这一问题 在重组小鼠杂交中，Fhit+/-xTrp 53 +/-与 诱导前胃和口腔癌，以表明Fhit作为一个守门基因产物，其丢失启动 肿瘤过程，可以预防或逆转AAVFHIT递送后的肿瘤 FHIT基因座在暴露于遗传毒性剂和FHIT时对复制损伤非常敏感 蛋白质在上呼吸消化道肿瘤的癌前病变发展的早期丢失或减少。 本项目的研究基于以下假设：在这些病变中替换FHIT可以：a） 根除这些器官的“癌区”中改变的细胞，从而防止复发; B）逆转 c）允许鉴定在癌症发生过程中Fhit损失改变的途径; FHIT基因治疗前后Fhit缺陷动物瘤前病变的发展，以及蛋白质 Fhit信号通路的药理学再激活的靶点。 因此，本研究项目的目的是：1）预防和逆转癌前病变和肿瘤 分别通过FHIT基因治疗Fhit+/-和Fhit+/-p53+/-小鼠的前胃病变; 2）优化 NQO在肿瘤抑制基因缺陷小鼠中诱导口腔癌并预防和逆转的方案 通过FHIT基因治疗在Fhit+/-和Fhit+/-p53+/-小鼠中的口腔肿瘤前病变和肿瘤; 3)通过多个FHIT基因“治愈”Fhit和Fhit/p53缺陷小鼠的NMBA和NQO诱导的病变 治疗剂量或FHIT基因治疗加Fhit途径靶向药物治疗。在每个特定目标中，Fhit-/- 将包括小鼠，并且将评估来自具有和不具有FHIT基因治疗的小鼠的组织， 细胞周期、DNA损伤反应和凋亡相关蛋白的表达，以及Fhit- 相互作用的蛋白质，以鉴定由Fhit缺失改变、由Fhit置换恢复的信号通路， 并且可能作为治疗上消化道和其它癌症的药物靶点。

FHIT Gene Therapy in Cancer Prevention and Treatment. We have developed murine upper digestive tract cancer models induced by oral /V-nitrosomethylbenzylamine(NMBA) or 4-nitroquinoline 1-oxide (NQO) treatment. Wild type (WT) mice are not very susceptible to these carcinogens but mice deficient for either Fhit or p53 develop a tumor burden up to 10 times greater than WT mice on exposure to NMBA or NQO, on predictable schedules. Mouse forestomach tumor burden is dramatically reduced by FHIT therapy early (tumor prevention) or late (tumor regression) after carcinogen exposure, and lung and cervical cancer studies are in progress. A caveat to mouse preclinical models is the prevailing notion that mouse tumors exhibit less genetic complexity and heterogeneity than human counterparts, so that human cancers may be less responsive to FHIT gene therapy. The proposed study aims to address this concern by testing FHIT gene therapy in genetically complex mouse tumors in the recombinant mouse cross, Fhit+/-xTrp53+/-, with induced forestomach and oral cancers, to show that Fhit, as a gatekeeper gene product whose loss initiates the neoplastic process, can prevent or reverse tumors after AAVFHIT delivery The FHIT locus is exquisitely susceptible to replication damage on exposure to genotoxic agents and Fhit protein is lost or reduced early in development of precancerous lesions of upper aerodigestive tract tumors. Research in this Project is based on the hypotheses that replacement of FHIT in these lesions could: a) eradicate the altered cells in the "cancer field" of these organs, thus preventing recurrences; b) reverse progression of established cancers; c) allow identification of pathways altered by Fhit loss during development of preneoplasia in Fhit deficient animals, before and after FHIT gene therapy, and of protein targets for pharmacological reactivation of Fhit signal pathways. Thus the aims of this research project are to: 1) prevent and reverse preneoplastic and neoplastic lesions, respectively, in forestomachs of Fhit+/- and Fhit+/-p53+/-mice by FHIT gene therapy; 2) optimize the protocol for NQO induction of oral cancers in the tumor suppressor deficient mice and prevent and reverse preneoplasias and neoplasias of the oral cavity in Fhit+/- and Fhit+/-p53+/-mice by FHIT gene therapy; 3) "cure" the Fhit and Fhit/p53 deficient mice of NMBA and NQO-induced lesions by multiple FHIT gene therapy doses or FHIT gene therapy plus Fhit pathway targeted drug treatment. In each specific aim Fhit-/- mice will be included and tissues from mice with and without FHIT gene therapy will be assessed for expression of cell cycle, DNA damage response and apoptosis-associated proteins, as well as Fhit- interacting proteins to identify the signal pathways altered by Fhit absence, restored by Fhit replacement, and likely to serve as drug targets for treatment of upper digestive tract and other cancers.