Investigation of Long Noncoding Rna in Dicer-Mediated Micro-Rna Reprogramming and Sorafenib Resistance in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common liver malignancy worldwide. In Taiwan, according to the report of Ministry of Health and Welfare, it is the second leading cause of cancer-related mortality and remains high prevalence now. In patients with HCC, the prediction of prognosis is complex compared with most solid tumors and the therapies are mainly limited to surgical resection of tumor, radiotherapy or targeted cancer therapies. Sorafenib is a first-line systemic drug for advanced HCC, but it is only displayed partial survival benefits and acquired drug resistance in HCC patients during long-term treatment. Hence, to investigate the molecular mechanisms of sorafenib resistance in liver cancer is an urgent and important issue worldwide. Recent evidence reveals that dysregulated miRNA and lncRNA expression of tumor cells may interfere with drug response, resulting in tumor progression. The miRNA-producing enzyme, Dicer, is crucial for the maturation of miRNAs and transcription of lncRNAs. This process involves in tumor progression and associates to clinical aggressiveness, prognosis and patient survival in various cancers. Our preliminary data showed that sorafenib sensitivity in liver cancer cells are mediated by Dicer expression. Hence, in this proposal, our goal is to clarify the regulatory mechanisms of Dicer and its downstream miRNAs and lncRNAs on liver cancer with acquired sorafenib resistance. The specific aims as following will help us to achieve the goal.SPECIFIC AIM 1: To investigate the regulatory mechanisms of Dicer in sorafenib sensitivity of liver cancer cells. 1-1. To examine whether the regulatory mechanisms of Dicer in sorafenib resistant liver cancer cells through transcriptional, post-transcriptional, translational, post-translational regulations or others.1-2. To identify the candidates or possible signaling pathway involve in regulation of Dicer.1-3. To confirm the linkage between candidates, Dicer and subsequent biological functions (sorafenib sensitivity and the cancer stem cell properties) in liver cancer cells.SPECIFIC AIM 2: To explore the roles of miRNAs and lncRNAs on sorafenib sensitivity of liver cancer cells. 2-1. To identify potential miRNAs and lncRNAs between sorafenib sensitive and resistant liver cancer cells.2-2. To elucidate the roles of miRNAs and lncRNAs in sorafenib sensitivity and cancer stemness in liver cancer cells.2-3. To clarify the regulatory axis between miRNAs and lncRNAs and Dicer in liver cancer cells.SPECIFIC AIM 3: To evaluate the physiological significance of Dicer, candidate molecules, miRNAs and lncRNAs in animal model and liver cancer patients with sorafenib resistance. 3-1. To investigate the physiological effects of Dicer, candidate molecules, miRNAs and lncRNAs in xenograft tumor formation assay. 3-2. To analyze the correlation between Dicer, candidate molecules, miRNAs and lncRNAs and sorafenib sensitivity in liver cancer patients.To accomplish these specific aims, it will help us to understand better about functions and molecular mechanisms of Dicer and its downstream miRNAs and lncRNAs in liver cancer progression and sorafenib resistance. Furthermore, the findings from this project may provide more information for precision medicine in developing anti-liver cancer pharmaceuticals.