Mechanism of Alcohol-induced RNA pol III dependent transcription

描述（由申请人提供）：一般认为饮酒会加重肝纤维化。酒精引起的肝纤维化会促进肝硬化的形成，从而增加患肝癌的风险。癌细胞具有一致的核仁肥大、核仁增大的细胞学特征，其中rrna由RNA pol I和pol III合成。这意味着原位转化与RNA pol -和iii依赖性转录的解除密切相关，因为核仁的大小反映了rRNA合成的水平。RNA pol III基因编码多种非翻译RNA，包括trna和5S RNAs。解除RNA pol iii依赖的转录，增强细胞trna和5S rrna的产生，导致翻译能力增加，促进细胞转化。尽管酒精已被广泛研究，但对于RNA pol iii依赖基因的转录是否会受到酒精的影响，目前还不清楚。由于RNA pol iii依赖性转录的调控与癌症密切相关，研究酒精如何影响这种转录将极大地提高我们对肝癌发展的理解。研究表明，酒精能够激活与人类癌症密切相关的MAP激酶。我们的假设是，酒精诱导应激，激活MAP激酶，特别是c-Jun n -末端激酶1 (JNK1)，并增加RNA pol III依赖性转录，导致肿瘤发展。首先，我们将在体内和体外测试酒精是否诱导RNA pol iii依赖转录的一类主要基因trna。其次，我们将确定酒精诱导的RNA pol III转录机制的变化。第三，我们将进一步研究介导酒精诱导的RNA pol iii依赖性转录失调的特定信号转导途径。此外，我们将利用长期酒精喂养的NS5A转基因小鼠和灌胃乙醇小鼠的肝组织进一步鉴定RNA pol iii依赖性转录在体内的变化。阐明这些由酒精引发的关键分子事件将为了解酒精性肝癌的发病机制提供新的见解，并为肝癌的康复提供新的治疗策略。

DESCRIPTION (provided by applicant): Alcohol consumption is generally thought to enhance liver fibrosis. Alcohol-induced liver fibrosis promotes formation of cirrhosis, which increases a risk of liver cancer. Cancer cells have a consistent cytological feature of nucleolar hypertrophy, enlarged nucleoli, where rRNAs are synthesized by RNA pol I and pol III. This implies that transformation in situ is closely linked to the deregulation of RNA pol I- and III-dependent transcription, because the size of the nucleolus reflects the levels of rRNA synthesis. RNA pol III genes encode a variety of untranslated RNAs, including tRNAs and 5S rRNAs. Deregulation of RNA pol III-dependent transcription, enhancing cellular tRNAs and 5S rRNAs production, leads to an increase in translational capacity to promote cell transformation. Although alcohol has been widely studied, nothing is yet known as to whether the transcription of RNA pol III-dependent genes might be affected by alcohol. Since deregulation of RNA pol III-dependent transcription is closely associated with cancers, addressing how alcohol affects this transcription will dramatically elevate our understanding of liver cancer development. Studies have shown that alcohol is able to activate MAP kinases, which are tightly linked to human cancers. Our hypothesis is that alcohol induces stress, activates MAP kinases, particularly the c-Jun N-terminal kinase-1 (JNK1), and increases RNA pol III- dependent transcription, leading to tumor development. First, we will test whether alcohol induces a major class of genes of RNA pol III-dependent transcription, tRNAs, in vivo and in vitro. Second, we will identify alcohol- induced changes in machinery of RNA pol III transcription. Third, we will further investigate the specific signal transduction pathways mediating the alcohol-induced deregulation of RNA pol III-dependent transcription. In addition, we will use liver tissues from chronically alcohol-fed NS5A transgenic mice and intragastric ethanol infusion mice to further identify the changes in RNA pol III-dependent transcription in vivo. Elucidating these key molecular events triggered by alcohol will provide new insights into the pathogenesis of alcohol-induced liver cancer to develop new therapeutic strategies for recovery from liver cancer. Public Health Relevance: The project seeks to elucidate the mechanism of alcohol-induced RNA pol III-dependent transcription in liver cancer and identify the specific pathway by determining MAP kinases, JNK1 and JNK2. Our new discovers of alcohol-induced changes in RNA pol III transcription machinery and our preliminary studies will provide valuable information to develop new drugs to therapy alcohol-associate liver diseases.