胰臟癌在美國以及台灣分別為二零一九年預期之第四名及第八名癌症死亡原因，其五年存活率僅有百分之九，由於預後極差而促使許多科學家致力於研究胰臟癌的成因。轉譯後的修飾於編碼和非編碼RNA上在疾病發展中所造成的影響是有著必然的貢獻，而近年來有許多研究指出這些轉譯後的化學修飾帶有著潛在的調控角色，而其中可逆的mRNA甲基化修飾被認為是有可能具有細微調控的能力。有研究發現老鼠中NOP2/Sun RNA methyltransferase family member 2 (NSUN2) 轉甲基酶的突變會導致神經發展障礙；而在乳癌中則發現過表達的NSUN2轉甲基酶，並且與癌症的進程有關。然而，在胰臟癌中尚未清楚研究探討NSUN2轉甲基酶的作用特徵及角色，因此本研究使用亞硫酸鹽反應作用於RNA上並搭配次世代定序來分析胰臟癌細胞株中NSUN2轉甲基酶的修飾位點。目前初步測定的數據中，發現在分別表現shScramble 與shNSUN2的BxPC-3細胞株中，定位出的六個5-甲基胞嘧啶修飾位點，有四個都位在HAT1基因的mRNA上。在探測癌細胞的常規功能性測試中，卻發現單獨降低NSUN2轉甲基酶表現量在BxPC-3細胞株中，對於細胞生長、細胞型態及gemcitabine化療藥物敏感性沒有顯著影響，顯示NSUN2在BxPC-3細胞株的生長率、型態控制，與gemcitabine作用機制中，可能扮演次要調控角色。

Pancreatic cancer is the estimated fourth leading cause of cancer death in the U.S. and the eighth in Taiwan in 2019. The poor prognosis of a five-year survival rate of only 9% prompts scientists to investigate the mechanisms of tumorigenesis. The contributions of post-transcriptional modifications in coding and noncoding RNA to disease pathogenesis are an indispensable factor. Accumulated studies indicate that among these underlying chemical modifications, the reversible messenger RNA (mRNA) methylation by NOP2/Sun RNA methyltransferase family member 2 (NSUN2) has the potential to be a fine-tuning regulator. Although reported mutations of Nsun2 lead to neurodevelopmental disorders in mice; and the overexpression of NSUN2 associates with breast cancer and cancer progression, the dynamic feature of NSUN2 in pancreatic cancer is still unknown. In this pilot study, we utilized RNA bisulfite sequencing to analyze NSUN2 target sites in mRNA of pancreatic cancer cell lines. From the preliminary data, a total of 6 candidate m5C sites were identified in the BxPC-3 cells stably expressing the shNSUN2 and the scramble control. 4 out of all 6 m5C sites were all located in the HAT1 gene. The phenotypic response of NSUN2 knockdown showed that NSUN2 has little effect on cell growth, morphology and gemcitabine sensitivity. Our result suggested that NSUN2 has a subtle role in cell proliferation, morphology and gemcitabine sensitivity in BxPC-3.

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