探討核醣核苷酸還原酶M2表現量在子宮頸癌的臨床意義

Ribonucleotide reductase（RR，核醣核苷酸還原酶）的作用是將核醣核苷酸（ribonucleotide）還原為去氧核醣核苷酸（deoxyribonucleotide）以做為DNA合成、修復的材料。人類細胞中RR由RRM1（Ribonucleotide reductase M1）及RRM2（Ribonucleotide reductase M2）或p53R2所組成。已知RRM2會影響到細胞的增生及分化，促進DNA修復，因此本研究為探討RRM2對於子宮頸癌細胞化療藥物抗藥性之影響及其與子宮頸癌癌化和病人存活預後之關係。在子宮頸癌細胞株CaSki、HeLa及SiHa處理化療藥物As2O3、cisplatin、gemcitabine，以MTT（3- (4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide）分析法及西方點墨法，發現不同子宮頸癌細胞RRM2表現量不同，對化療藥物的耐受性也不同，故推測RRM2與子宮頸癌細胞株對化療藥物的耐受性有關，接著將RRM2表現量高的SiHa，以VSV-G pseudotyped lentivirus-shRNA使RRM2蛋白的表現下降，結果顯示RRM2表現量多寡會影響子宮頸癌細胞SiHa對cisplatin的抗藥性，但不會影響對gemcitabine及taxol之抗藥性。以子宮頸組織晶片研究RRM2免疫組織化學染色之表現，以H score定義RRM2高度表現及低度表現，檢測RRM2蛋白表現與子宮頸癌病人癌化及臨床病理特徵、復發及預後存活之關係。於子宮頸癌組織，RRM2表現較HSILs、LSILs及正常子宮頸組織強。以Chi-square或Fisher’s exact作統計分析，發現RRM2的表現與子宮頸癌化與年齡（p = 0.004）、期別（p = 0.027）、子宮頸癌基質侵犯深度（p < 0.001）、腫瘤直徑（p = 0.001）、細胞分化程度（p < 0.001）、轉移子宮頸旁組織（p = 0.022）有關，且RRM2免疫組織化學染色強的子宮頸癌病人預後及存活較差，因此，RRM2可以視為癌症中不好的預後因子，且RRM2高對cisplatin有耐受性，未來將尋找其他更適合的化療藥物。

關鍵字

核醣核苷酸還原酶M2 ；子宮頸癌；化療藥物耐受性；組織晶片

並列摘要

Ribonucleotide reductase (RR) is the enzyme that catalyzes the formation of deoxyribonucleotides from ribonucleotides. Deoxyribonucleotides in turn are used in the synthesis of deoxynucleic acid (DNA) and DNA repair. The ribonucleotide reductase consists of RRM1 and RRM2 or p53R2 subunits which form an active heterodimeric tetramer in human cells. RRM2 correlates with cell proliferation, differentiation, and promotes DNA repair. The objectives of this study were to investigate the effect of RRM2 on chemotherapeutic resistance of cancer cells of uterine cervix and its relationship with cervical carcinogenesis and prognosis of cancer patients. Cervical cancer cell lines (CaSki, HeLa and SiHa) treated with chemotherapeutic drugs such as arsenic trioxide, cisplatin and gemcitabine, were analyzed by MTT [3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay and western blot, and found to have different RRM2 expression and different chemotherapeutic drugs resistance. RRM2 expression levels may be associated with the chemotherapeutic resistance of cervical cancer cell lines. Thereafter, we used VSV-G pseudotyped lentivirus-shRNA system for RRM2 silencing in SiHa, cervical cancer cells and found that RRM2 expression levels may affect chemotherapeutic resistance of cisplatin, but not gemcitabine and taxol. Immunoreactivity of RRM2 protein had been evaluated by immunohistochemical methods with cervical tissue microarrays. High and low expression of RRM2 protein were scored using H score. The purposes of this study were to define the association of RRM2 expression with carcinogenesis and variable clinicopathological characteristics of cervical cancer. RRM2 expression of cervical cancer tissues was higher than that in HSILs, LSILs and normal cervical tissues. RRM2 expression was significantly associated with age (p = 0.004), stage (p = 0.027), stromal invasion (p < 0.001), tumor diameter (p = 0.001), cell differentiation (p < 0.001) and paramemtrium invasion (p = 0.022). Furthermore, positive RRM2 expression was significantly associated with worse recurrence and poor survival of cervical cancer patients.

並列關鍵字

Ribonucleotide reductase M2 ； cervical cancer ； resistance ； tissue array

參考文獻

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探討核醣核苷酸還原酶M2表現量在子宮頸癌的臨床意義

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