FHIT Gene Therapy in Cancer Prevention and Treatment

描述（申请人提供）：FHIT基因治疗在癌症防治中的应用。我们建立了口服/ v -亚硝基甲基苄胺（NMBA）或4-硝基喹啉- 1-氧化物（NQO）诱导的小鼠上消化道肿瘤模型。野生型（WT）小鼠对这些致癌物不太敏感，但缺乏Fhit或p53的小鼠在可预测的时间内暴露于NMBA或NQO时，肿瘤负荷比WT小鼠高10倍。致癌物暴露后，FHIT治疗早期（肿瘤预防）或晚期（肿瘤消退）显著减轻小鼠前胃肿瘤负担，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，普遍认为小鼠肿瘤比人类肿瘤表现出更少的遗传复杂性和异质性，因此人类癌症对FHIT基因治疗的反应可能更小。本研究旨在解决这一问题，通过FHIT基因治疗基因复杂的小鼠肿瘤，在重组小鼠杂交FhitxTrp53中，诱导前胃癌和口腔癌，表明FHIT作为一个gatekeeper基因产物，其缺失启动肿瘤过程，可以预防或逆转AAVFHIT传递后的肿瘤。FHIT基因座在暴露于基因毒性物质时非常容易受到复制损伤，并且FHIT蛋白在上消化道肿瘤癌前病变发展的早期丢失或减少。该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“癌区”中的改变细胞，从而防止复发；B)逆转既定癌症的进展；c)允许在Fhit基因治疗前后，在Fhit缺陷动物的瘤前病变发展过程中，识别Fhit缺失所改变的通路，以及Fhit信号通路药理再激活的蛋白靶点。因此，本研究项目的目的是：1)通过Fhit基因治疗Fhit和Fhitp53小鼠前胃分别预防和逆转肿瘤前病变和肿瘤前病变；2)优化抑癌基因缺陷小鼠NQO诱导口腔癌的方案，通过Fhit基因治疗Fhit和Fhitp53小鼠，预防和逆转Fhit和Fhitp53小鼠的口腔瘤前病变和肿瘤发生；3)通过多剂量Fhit基因治疗或Fhit基因治疗加Fhit通路靶向药物治疗，“治愈”NMBA和nqo诱导的Fhit和Fhit/p53缺陷小鼠病变。在每个特定的目标中，将包括Fhit-/-小鼠，并评估接受和未接受Fhit基因治疗的小鼠组织的细胞周期、DNA损伤反应和凋亡相关蛋白的表达，以及Fhit-相互作用蛋白，以确定Fhit缺失改变的信号通路，Fhit替代恢复的信号通路，并可能作为治疗上消化道和其他癌症的药物靶点。

DESCRIPTION (provided by applicant): 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, FhitxTrp53, 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 Fhitp53 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 Fhitp53 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.