- 學位論文
探討新型核糖核苷酸還原酶抑制劑於大腸直腸癌之機轉
The study for molecular mechanisms of a novel RNR inhibitor in colorectal cancer
摘要
大腸直腸癌為全球發生率位居前三的癌症，在台灣十大死因之中也高居第三。先前研究指出核糖核苷酸還原酶(ribonucleotide reductase)是DNA合成與修復重要的酵素，並在大腸直腸癌之中協助癌細胞的DNA合成與生長，因此核糖核苷酸還原酶抑制劑被視為重要的癌症治療藥物。目前一種新型的核糖核苷酸還原酶抑制劑COH29已進入臨床試驗，其功能為阻擋自由基在核糖核苷酸還原酶子單原RRM1與RRM2之間的傳遞，進而抑制癌細胞DNA之生成。為探討此藥物在大腸直腸癌中的機轉，本實驗研究COH29與大腸直腸癌生長與轉移息息相關的鈣離子之間的訊息傳遞機轉。結果顯示此藥物能夠經由阻擋鈣池調控鈣離子的流入 (store-operated calcium entry)，而影響鈣離子調控之粒線體功能與下游路徑，進而抑制大腸直腸癌細胞的發炎反應與侵襲能力。本研究使用微陣列資料與Connectivity Map和LINCS cloud資料庫比對，結果顯示此藥物與許多抗癌藥物具有相同的基因圖譜，更加證明COH29可望能成為有效的抗癌藥物。本研究亦納入418名台灣大腸直腸癌患者，並篩選出2個RRM2B的單一核苷酸基因多型性標地，探討RRM2B基因多型性與大腸直腸癌轉移之相關性。結果顯示當rs2607658帶有T基因型時，大腸直腸癌病人的CEA指數在手術後較容易下降，顯示其成為生物標記的發展性。本研究探討核糖核苷酸還原酶抑制劑COH29在大腸直腸癌細胞之中的抗腫瘤機轉可能是經由抑制鈣池調控鈣離子流入而達成的。經由資料庫分析也發現COH29之基因圖譜和諸多抗腫瘤藥物有相似之處，證實此藥物有開發成為抗腫瘤藥物之潛力，日後將對於大腸直腸癌病患提供更加有效的標靶治療。此外經由基因多型性與大腸直腸癌症的關聯性研究可提供臨床醫師未來能有更精確的診斷與治療。
並列摘要
Colorectal cancer is the leading cancer in incidence and mortality world-wide. Ribonucleotide reductase (RNR) plays indispensable roles in DNA synthesis, growth and metastasis of cancer cells. A promising new drug COH29 has been developed as a RNR inhibitor to inhibit tumor regression in several cancers, such as leukemia and colorectal cancer. COH29 inhibits the enzyme activity by ligand-radical interception and interferes with the RRM1-RRM2 subunits interaction, yet the anti-tumor mechanism has to be further clarified. In this study, we conducted serial translational experiments from clinical genomics to tumor biology. Results showed that COH29 may inhibited colorectal cancer cells progression through the inhibition of store-operated calcium influx and attenuation of mitochondrial calcium influx to influence the functions and signaling of mitochondria. Bioinformatics approaches were performed and results indicated that by querying the COH29 treated HT29 cells gene signature with Connectivity Map and LINCS cloud database, several antineoplastic agents presented similar gene signatures with COH29. In the clinical approach, 418 colorectal cancer patients were recruited. Two single nucleotide polymorphisms (SNPs) of RRM2B were chosen to conduct association study between colorectal cancer progression and RRM2B SNPs. Results indicated patients with T genotype of rs2607658 is associated with decreased of CEA levels after surgery. Our results suggested that RRM2B has association with CEA marker in CRC patients, and the RNR inhibitor COH29 can inhibit colorectal cancer cell metastasis possibly through the attenuation of cellular calcium signaling.