成員簡介

賴亮全教授

賴亮全教授
  • 賴亮全

  • 職  稱:教授
  • 學  歷:美國伊利諾大學香檳校區 博士
  • 專  長:基因體與細胞調控
  • 聯絡電話:(02)23123456 ext. 288241
  • E-mail:llai@ntu.edu.tw

研究方向:

  本實驗室主要研究的方向是利用基因體微陣列(microarray)及次世代定序(next generation sequencing)的技術、輔以生物資訊(bioinformatics)的工具,來尋找與疾病相關的生物標記[例如:基因、單核苷酸多型性(single nucleotide polymorphism, SNP)、微小RNA (microRNA)、DNA甲基化 (DNA methylation)、長片段非轉譯RNA(long non-coding RNA)等],及利用分子生物學的技術探討與疾病形成與演變相關的分子機轉。盼本實驗室的研究成果可助於發展針對不同疾病的個人化醫療。

 

研究主題:

  過去10多年的研究主軸為於乳癌細胞中、研究缺氧基因NDRG1及長片段非編碼核糖核酸NDRG1-OT1在不同氧環境下的轉錄及表觀遺傳的調控機制。相關論文說明如下:

  首先,我們研究微小RNA (microRNAs)N-myc downstream-regulated gene 1 (NDRG1)之間的調控關係。利用Nanostring nCounter的生物晶片、生物資訊的預測分析及實驗驗證,我們發現覆氧時,miR-769-3可抑制NDRG1的基因與蛋白質表現。此外,miR-769-3p還可藉由誘發細胞凋亡來抑制細胞的生長。本研究是第一個證明NDRG1可受到miRNA的調控,也是第一個探討miR-769-3p功能的研究。此論文已發表於Scientific Reports, 4:5908, 2014 (IF, 排名及%: 4.609, 10/62=16% in Multidisciplinary Sciences)。

  另外,過去研究指出長片段非編碼核糖核酸(long non-coding RNA; lncRNA)會受到外在刺激活化來調控其目標基因的表現而造成癌細胞的惡化。目前在乳癌中、受氧調節之lncRNA的表現圖譜仍不清楚。因此,我們去鑑定乳癌細胞中影響的lncRNA,並探討lncRNA調控其目標基因的機制。本研究使用次世代定序技術檢查於常氧,缺氧和覆氧情況下,乳癌細胞中lncRNA的表現圖譜。找到了472個lncRNA的表現量受氧濃度影響,並選擇了反應最大的lncRNA NDRG1-OT1做進一步研究。在常氧的條件下,大量表現NDRG1-OT1並用微陣列分析找到受NDRG1-OT1調節的目標基因及其功能。在這些目標基因中,我們發現NDRG1的基因表現量和蛋白質含量皆能被NDRG1-OT1抑制。最後,免疫共沉澱實驗顯示NDRG1-OT1是通過促進泛素蛋白來降解NDRG1蛋白。本研究首先發現在乳癌細胞中NDRG1蛋白的調控可經由lncRNA NDRG1-OT1的表觀遺傳來達成。此論文已發表於Oncotarget, 2017。

  接著我們進一步探討NDRG1-OT1如何DNA轉錄調控目標基因NDRG1。我們利用螢光素酶報告基因檢測法(Luciferase reporter assays)、質譜儀、生物資訊工具、基因調控與西方點漬等方法去尋找與NDRG1-OT1共同作用的蛋白質。出乎意外地,不同片斷的NDRG1-OT1對相同的目標基因NDRG1竟有不同的功能。第一段NDRG1-OT1(1–149 bp)對NDRG1活性無任何作用;第二段NDRG1-OT1(150–263 bp)可藉由增加與hnRNPA1連結能力進而抑制NDRG1;第三段NDRG1-OT1(264–392 bp)藉由與缺氧促進因子(hypoxia induced factor-1 alpha)結合而促進NDRG1活性;第四段NDRG1-OT1(393–508 bp)藉由缺氧時降低KHSRP而抑制NDRG1的活性。本研究中,我們首度發現長鏈非編碼核糖核酸(lncRNA)新的調控方式,即不同片段的lncRNA對於相同的目標基因可藉由連結不同的蛋白質而有南轅北轍的功用。此論文已發表於RNA biology, 2018 (IF, 排名及%: 5.269, 50/290=17% in Biochemistry & Molecular Biology)。近年來,我們亦探討並發表數個lncRNA的作用機制。例如: MTORT1MALAT1Lnc-SLC15A1-1等。

前往學術著作

Liang-Chuan Lai, Ph.D.
Professor,
Graduate Institute of Physiology,
National Taiwan University College of Medicine
Taipei, Taiwan

TEL: 886-(02)23123456 ext. 88241
FAX: 886-(02)23938235
E-mail: llai@ntu.edu.tw

Academic Hub

ORCID ID: 0000-0002-3913-5338

ResearcherID: B-4768-2009

Scopus Author ID: 720261626


Lab topic
Our major research interests are using microarray or next generation sequencing to explore the cancer genomics. Approaches to understand the mechanism of cancer genome by investigating gene expression profiling, copy number variation, single nucleotide polymorphism, epigenetics and microRNA in several cancers, including lung cancer, breast cancer, and esophageal cancer.
Recently we identified that several semaphorin gene family members can be used as potential therapeutic targets, and that SEMA5A may be useful as a prognostic biomarker for non-smoking women with non-small cell lung carcinoma.


Research topic
Investigation of regulatory mechanism of NDRG1 upon reoxygenatio
Hypoxia has been intensively investigated over the past decades based on the observations that hypoxic tumors were more resistant to therapy and had a worse prognosis. However, the oxygen concentration within hypoxic tumors was highly variable, because tumor vasculature was both inefficient and unstable. The hypoxic regions could become rapidly re-perfused or re-oxygenated. Several studies have been reported that tumor cells displayed increases in drug resistance and metastatic potential after exposed to hypoxia/reoxygenation insults. Therefore, it is necessary to consider hypoxia and reoxygenation as two parts of the same stress response as they were inevitably associated with each other. Although cellular adaptation to hypoxia was well documented, little was known about adaptive mechanisms to reoxygenation.
In our previous genomic study on breast cancer cells upon reoxygenation, we identified 127 genes involved in this response. Pathway analysis revealed that these oxygen-responsive genes were enriched in HIF-1-alpha transcription factor network, and validated targets of C-MYC transcriptional activation. Among these differentially expressed genes upon reoxygenation, NDRG1 had the maximal response and was regulated by MYC signalling pathway. Therefore, we hypothesize that NDRG1 may play an important role in tumor adaptation to fluctuation of oxygen concentrations. Although several studies suggested that NDRG1 is induced by hypoxia and associated with metastasis, the regulatory mechanism of NDRG1 remains elusive and its function under reoxygenation is still unclear. Hence, we propose to comprehensively investigate the regulatory mechanism of NDRG1 upon changes in oxygen concentrations. In order to prove our hypothesis, we propose to conduct experiments with the following specific aims:

  1. Identification of transcription factors that directly regulate NDRG1 and their binding sites;
  2. Identification of microRNAs that directly regulate NDRG1 and their binding sites;
  3. Investigation of methylation status in the promoter of NDRG1 regulating its expression;
  4. Investigation of functional roles of NDRG1 using in vitro and in vivo assays.

Using genetic approaches, functional assays, and in silico analysis, this study will allow us to get a deep insight of the genetic mechanisms and functional roles of NDRG1 upon oxygen variation in transformed cells. By a better understanding of the molecular mechanism that cancer cells adapt to the tumor microenvironment, we hope to contribute in developing a more specific therapeutic regime to treat cancer.

Regulation of transcription and metastasis of semaphorin family in lung cancer
Lung cancer is the leading cause of cancer death in Taiwan. The increase of lung cancer mortality rate in Taiwan has become the highest in the world. Despite advances in early detection and standard treatment, lung cancer is still often diagnosed at an advanced stage and has a poor prognosis, with less than 15% of overall 5-year survival rate. Although smoking is the major risk factor for lung cancer, only < 20% smokers have lung cancer. Furthermore, transforming normal bronchial epithelial cells to lung cancer requires a number of genetic molecular lesions. Although several genes, such as EGFR, KRAS, PI3K, p53, etc., have been reported to be involved in lung tumorigenesis, the detail mechanisms still remain unclear. In our previous genomic study on non-smoking female lung cancer patients, we identified that several genes in semaphorin (SEMA) family (e.g. SEMA3B, SEMA3G, SEMA5A, SEMA6A, and SEMA6D) were very significantly down-regulated. Functional analysis also revealed that genes involved in axonal guidance signaling and Ephrin receptor signaling were in the top three enriched functional categories. However, little is known about the role of SEMA genes in the lung cancer. Because these guidance molecules act in general to regulate cell migration and adhesion, we hypothesize that they are involved in mechanisms of disease progression in lung carcinogenesis. In order to prove our hypothesis, we propose to conduct experiments with the following specific aims:

  1. To investigate the effect of semaphorin genes in lung carcinogenesis by over-expressing SEMA genes in human lung cancer cells;
  2. To understand the molecular mechanisms of semaphorin genes in lung carcinogenesis by microarray analysis;
  3. To further characterize the functional roles of semaphorin genes in athymus nude mouse model.

Using genetic approach, functional assays, and microarray analysis, this study will allow us to get an insight of the functional roles and genetic mechanisms of semaphorin gene family in lung cancer. By a better understanding of the molecular origins and evolution of the disease, we hope to contribute in developing a more specific therapeutic regime to treat lung cancer.

博士班學生

劉家銘
蘇麗宇

碩士班學生

朱庭汶
林俐妤
周凱軒
黃照穎