應用RNA干擾抑制 EGFR 與 MRP2 之基因表現以降低口 腔癌的化療抗藥性

RNA Interference of MRP2 and EGFR Genes Reduces Chemo-Resistance of Oral Cancer Cells

古佾筑(Yi-Chu Ku)

指導教授 ： 戴建國

國立中正大學/理學院/生命科學系分子生物研究所/碩士(2014年)

摘要

口腔癌的發生率在台灣排行第五位，此外它還有較高的發病率和死亡率。如今在所有癌症藥物治療中都遇到了困境，因為腫瘤治療後有一部分的人會產生抗藥性，因此需要更進一步的輔助性治療。先前許多研究已經證實了MRP2的主要功能是將細胞內化療藥物排出細胞，此外許多文獻指出在具有抗藥性的細胞中，MRP2基因表現會增加。另外，有大量的研究也顯示，EGFR(表皮生長因子受體)在腫瘤發展過程中扮演一個非常重要的角色，而且EGFR過度活化也會導致細胞產生抗藥性。因此，我們利用慢病毒載體調控的RNAi機制，抑制OSCC細胞中MRP2和EGFR的表達，接著去檢測化療藥物的細胞毒性，以了解在口腔癌中是否可以增加藥物對癌細胞的毒殺。在我們先前的研究中，發現抑制MRP2的基因表現並不能降低OC2細胞對cisplatin 的IC50。而之後使用半定量的RT-PCR分析顯示與其他口腔癌細胞相比OC2 的MRP2表達量並不高。所以，我們培養了對cisplatin 有抗藥性的OC2 細胞株(OC2CisR)， 並且在實驗結果中也顯示抗藥性細胞內的MRP2表現量有增加。我們分別抑制了有抗藥性的OC2細胞株內MRP2和EGFR的基因表現，之後發現抑制基因表現後抗藥性細胞株對藥物敏感性有增加。而在裸鼠的皮下腫瘤模型結果顯示，在OC2CisR細胞中分別抑制 MRP2或EGFR的基因表現，並沒有增加cisplatin的治療功效。值得一提的是，實驗結果顯示合併抑制這兩基因的組合是最有效的。希望在未來，我們能夠提供一個改善的輔助療法去協助已產生抗藥性的癌症患者。

關鍵字

口腔癌 ； 抗藥性

並列摘要

Oral squamous cell carcinoma (OSCC) is the fifth most common cancer in Taiwan, and the tumor has high incidence and mortality rate. It would be in a predicament that a part of cancer patient suffered recurrence after chemotherapy. Therefore, we need to find some ways to improve chemotherapy efficacy. Many studies have confirmed that the main function of MRP2 is to export chemotherapy drug out of cells and it was also found that MRP2 is frequently up-regulated in drug resistant cancer cells. Plenty of researches also show that EGFR plays an important role in promoting cancer progression and its activation causes drug resistance. Thus, I knock down the expression of EGFR and MRP2 of OSCC cells by lentiviral vector-mediated RNAi and analyze whether the cytotoxicity of chemotherapy drugs to OSCC could be enhanced. In our previous study, I have found that knockdown of MRP2 cannot decrease the IC50 of cisplatin to OSCC cell line OC2, and I have also recently found that the MRP2 expression in OC2 was much lower than the other oral cancer cell lines by semi-quantitative RT-PCR. Recently, I have developed a cisplatin-resistant OC2 cell line (OC2CisR) and determine that OC2CisR has a higher MRP2 expression than parental OC2 cells. Next, I knocked down both the MRP2 and EGFR of OC2CisR by lentiviral-mediated RNAi and observed a higher sensitivity to cisplatin than single knockdown of MRP2 or EGFR. The subcutaneous tumor model of OC2CisR cells in nude mice also indicated that only dual knockdown showed an improved therapeutic efficacy. I proposed that our strategy could provide a better adjuvant therapy to patients who have developed cisplatin-resistant cancers.

並列關鍵字

drug resistant ； MRP2 ； EGFR ； oral cancer

參考文獻

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