發炎反應下Musashi-1所引導之大腸癌幹細胞之可塑性的鑑定與描述

Abstract

大腸癌消耗了大量的花費與醫療資源。此外大腸癌為台灣癌症中好發率最高的癌症。雖然如此， 大腸癌的發生卻是最可被控制的癌症，藉由早期的診斷能夠大幅的減少大腸癌的發生。除了遺傳因 素之外，大腸癌的危險因子主要為環境因子與年齡。西方化的生活習慣有關之長期腸道發炎與腸道 菌生態系之不平衡，配合上一連串的基因變異最後導致大腸癌的形成。在此計晝當中，基於幹細胞 基因與化學誘導動物發炎模式來探討大腸癌形成之過程與探索新穎之生物標把作為早期診斷、預後 與具有用以大腸癌之治療相關之因子之可能性。外來之刺激例如發炎作用，而使核醣核酸(RNA)與核 醣核酸結合蛋白(RNA binding protein)形成核醣核酸粒(RNA granules)。Musashi-1是大腸幹細胞與大 腸癌幹細胞之幹細胞基因。Musashi-1同時亦為核醣核酸之結合蛋白並且也能形成核醣核酸粒。微小 非編碼核醣核酸包含於此核醣核酸粒當中，此核醣核酸粒可能具有影響微核醣核酸(microRNA)的標 的作用與新穎微核醣核酸之生和成，進而與大腸癌之生成有關。此外，被Musashi-1核醣核酸粒所活 化之酵素激酶亦可能與非典型之訊息傳遞途徑、轉錄因子(transcription factor)之活化與轉錄體 (transcriptome)皆與大腸癌或大腸癌幹細胞有關。因此，為了探索這些可能性，將建立透過IRES-eGFP 進行Musashi-1表現追蹤之基因轉殖鼠(transgenic mice)。再利用AOM/DSS化學誘導小鼠大腸癌生成 之模式於此基因轉殖鼠，用以模擬發炎反應誘導之大腸癌形成模式以探討Musashi-1核醣核酸粒與大 腸癌形成之相關性。本計晝之研究目標主要是以幹細胞為主體，藉由以Musashi-1為主之幹細胞追蹤 技術用以發掘新穎表面抗原之研究，並且研究以新穎表面抗原與微核醣核酸表現之分子特徵作為大 腸癌診斷與預後之可能性。此外，藉由此研究探索之非典型訊息傳遞途徑，或能為複合治療(combined therapy)提供大腸癌之藥物治療標靶用以治療大腸癌或是預防大腸癌之發生。綜觀此計晝，藉由匯集 幹細胞基因，Musashi-1，與抗逆境之核醣核酸粒的形成與化學誘導發炎形成大腸癌之動物模式，去 探討細胞命運(cell fate)與細胞可塑性(cell plasticity)於大腸癌形成的過程與其可能映射出之新穎表面 抗原，微核醣核酸表現之分子特徵與非典型之訊息傳遞鍊與傳遞網絡。這些研究成果希望能夠提供 大量有用之資訊以對抗大腸癌之發生，並且增進人類之健康與生活品質。

Colorectal cancer (CRC) consumes huge amount of healthcare spending and medical resources. Besides, CRC is the leading incidence of cancer in Taiwan. Albeit the high incidence, CRC is controllable by early diagnosis and prevent the neoplasia of CRC. Not only genetic background, risk factors for CRC is also largely environmental and age related. Chronic intestinal inflammations associating with Western life style or imbalance of intestinal microbial ecosystem, combine with a serial of genetic hits causes the neoplasia of CRC. In this proposal, a study model system based on colon stemness genes and inflammation animal models are deployed to explore the CRC formation and search for the factors for early diagnosis, prognosis or potential therapeutic target of CRC. Cytosolic RNA protein aggregation forms RNA granules upon extracellular stress stimulations including inflammations. Musashi-1 is a stemness gene and also the marker for colon stem cells and CRC stem cells. Musashi-1 is also a RNA-binding protein and forms RNA granules as a ribonuclear protein complex. Small non-coding RNAs are associated with Musashi-1 RNA granules and the interactions of Musashi-1 and those non-coding small RNAs might be critical for CRC neoplasia by gene targeting and biogenesis of novel small non-coding RNAs. Furthermore, protein kinases activations by Musashi-1 granules might contribute to non-canonical signal transduction pathways, transcription factor networks, and global transcriptome changes of CRC or colorectal cancer stem cell. To explore those possibilities, animal model systems of Musashi-1 expression tracking by IRES-eGFP knockin transgenic mice are expected to establish. AOM/DSS is deployed to in those two transgenic mice to mimic chronic inflammation induced CRC formation. The aim of this project is to identify cancer stem cell orientated novel surface markers by cancer stem cell lineage tracking method based on Musashi-1 expression and non-coding small RNAs as molecular signatures for CRC diagnosis and prognosis. Furthermore, the non-canonical signaling pathways identified by those approaches might also provide clues for developing more efficient combined therapies for CRC treatments or preventions. In summary, the project is based on the converging the current knowledge of stemness genes, Musashi-1, stress resistance RNA granules, and established a representative animal model system and apply it to a chemical induced and inflammation-driven CRC formation system to unlock the cell fate and cell plasticity determination processes of CRC neoplasia. By those experiment design and approaches, uncovered novel surface markers, molecular signatures, and non-canonical signaling transduction networks should wealthy information or potential applications for fighting with CRCs and improve human health and life qualities.