AZ20增强吉西他滨杀伤胰腺癌细胞活性的研究
发布时间：2018-07-21 12:41
【摘要】：胰腺癌(pancreatic cancer)是一种死亡率极高的恶性肿瘤,因为早期诊断困难,所以多数患者发病时已处于癌症晚期,并往往伴随着癌症的转移。目前,以吉西他滨(gemcitabine)为主的化疗是治疗胰腺癌最主要的手段,但疗效甚微。因此,通过引入新药或药物组合来提高化疗效果是一种合理的选择。DNA损伤应答(DNA damage response,DDR)是细胞内一套精细且复杂的信号网络,为时刻受到内外源DNA损伤压力的细胞提供保护。DDR通路涉及DNA复制、DNA损伤修复和细胞周期检验点等通路,通过协调这些信号通路的运行,维持基因组的稳定性,促进细胞的存活。ATR(ataxia telangiectasia and Rad 3 related)是DDR通路中的关键蛋白,它参与DNA损伤的识别,并通过激活CHK1等下游蛋白修复DNA损伤、缓解DNA复制压力和活化细胞周期检验点等功能。相比正常细胞,癌细胞往往更依赖于ATR活性,因此ATR被认为是很有前景的癌症治疗靶点。本论文选用新开发的高效ATR选择性抑制剂AZ20,考察其单独以及与吉西他滨联合使用对胰腺癌细胞的抗肿瘤活性。在胰腺癌细胞中的结果显示,AZ20能够抑制细胞生长,但对细胞死亡的影响较小。AZ20能够抑制ATR下游CHK1-CDC25C-CDK1信号通路的活性,同时上调DNA损伤。这些结果暗示,AZ20对细胞周期检验点有两个方面的影响:抑制ATR所产生的抑制作用和因诱导DNA损伤而产生的激活作用。依据AZ20能够诱导S期和G2/M期阻滞的结果推知,AZ20对细胞周期检验点的净影响是上调DNA损伤所导致的激活作用。AZ20对DNA损伤的诱导将为其与DNA损伤类药物联用提供分子基础。吉西他滨作为胰腺癌的一线化疗药物已经被使用了接近20年,但单独使用治疗效果非常有限。因为吉西他滨的主要作用机制是诱导细胞发生DNA损伤,所以我们尝试将AZ20与吉西他滨联用。结果表明,AZ20能增加吉西他滨的细胞毒性作用、削弱吉西他滨诱导的细胞周期阻滞和增强吉西他滨诱导的细胞死亡。同时,AZ20能增加吉西他滨诱导的DNA损伤、抑制吉西他滨激活细胞周期检验点和下调吉西他滨诱导的核苷酸还原酶(Ribonucleotide reductase,RNR)表达。这些结果指出,AZ20通过抑制ATR的DNA修复功能、促进细胞周期运行和降低RNR活性这几个方面来上调吉西他滨诱导的DNA损伤,进而增加吉西他滨诱导的细胞死亡。综上所述,本论文的研究证明,AZ20能够增强吉西他滨杀伤胰腺癌细胞的活性,指出通过靶向ATR来增加DNA损伤类药物的抗胰腺癌活性是一种有效可行的治疗策略。本论文的研究为AZ20的临床应用打下坚实的实验基础,为胰腺癌的临床治疗提供新思路。
[Abstract]:Pancreatic cancer (pancreatic cancer) is a malignant tumor with high mortality. Because of the difficulty of early diagnosis, most of the patients were in advanced stage of cancer and often accompanied by cancer metastasis. Currently, gemcitabine (gemcitabine)-based chemotherapy is the most important treatment for pancreatic cancer, but the efficacy is minimal. Therefore, it is a reasonable choice to improve the effect of chemotherapy by introducing new drugs or combination of drugs. Damage response is a set of fine and complex signal network in cells. Providing protection for cells under constant internal and external DNA damage, the DDR pathway involves pathways such as DNA replication, DNA damage repair and cell cycle verification points, which maintain genomic stability by coordinating the operation of these signaling pathways. ATR (ataxia telangiectasia and Rad3 related is a key protein in the related pathway. It participates in the recognition of DNA damage, and restores the damage by activating downstream proteins such as CHK1, relieving the replication pressure and activating the cell cycle test points. Cancer cells tend to be more dependent on ATR activity than normal cells, so ATR is considered a promising cancer treatment target. In this study, the antitumor activity of AZ20, a highly efficient ATR selective inhibitor, was investigated on pancreatic cancer cells alone and in combination with gemcitabine. The results in pancreatic cancer cells showed that AZ20 could inhibit cell growth, but had little effect on cell death. AZ20 could inhibit the activity of CHK1-CDC25C-CDK1 signaling pathway downstream of ATR and up-regulate DNA damage. These results suggest that AZ20 has two effects on cell cycle test sites: inhibition of ATR and activation of DNA damage. According to the results that AZ20 can induce arrest of S phase and G 2 / M phase, we infer that the net effect of AZ20 on cell cycle test point is that the activation induced by up-regulation of DNA damage .AZ20 induction of DNA damage will provide a molecular basis for the combination of AZ20 and DNA damage drugs. Gemcitabine has been used for nearly 20 years as a first-line chemotherapeutic agent for pancreatic cancer, but the efficacy of gemcitabine alone is very limited. Because the mechanism of gemcitabine is to induce DNA damage in cells, we try to combine AZ20 with gemcitabine. The results showed that AZ20 could increase the cytotoxicity of gemcitabine, weaken the cell cycle arrest induced by gemcitabine and enhance the cell death induced by gemcitabine. At the same time, AZ20 could increase the DNA damage induced by gemcitabine, inhibit the gemcitabine-activated cell cycle test point and down-regulate the expression of ribonucleotide reductase (RNR) induced by gemcitabine. These results suggest that AZ20 upregulated gemcitabine-induced DNA damage by inhibiting the DNA repair function of ATR, promoting cell cycle operation and decreasing RNR activity, and then increased the cell death induced by gemcitabine. To sum up, the present study proves that AZ20 can enhance the activity of gemcitabine in killing pancreatic cancer cells. It is pointed out that targeting ATR to increase the anti-pancreatic cancer activity of DNA-damaging drugs is an effective and feasible therapeutic strategy. The research in this paper lays a solid experimental foundation for the clinical application of AZ20 and provides a new idea for the clinical treatment of pancreatic cancer.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：R735.9
本文编号：2135557
[Abstract]:Pancreatic cancer (pancreatic cancer) is a malignant tumor with high mortality. Because of the difficulty of early diagnosis, most of the patients were in advanced stage of cancer and often accompanied by cancer metastasis. Currently, gemcitabine (gemcitabine)-based chemotherapy is the most important treatment for pancreatic cancer, but the efficacy is minimal. Therefore, it is a reasonable choice to improve the effect of chemotherapy by introducing new drugs or combination of drugs. Damage response is a set of fine and complex signal network in cells. Providing protection for cells under constant internal and external DNA damage, the DDR pathway involves pathways such as DNA replication, DNA damage repair and cell cycle verification points, which maintain genomic stability by coordinating the operation of these signaling pathways. ATR (ataxia telangiectasia and Rad3 related is a key protein in the related pathway. It participates in the recognition of DNA damage, and restores the damage by activating downstream proteins such as CHK1, relieving the replication pressure and activating the cell cycle test points. Cancer cells tend to be more dependent on ATR activity than normal cells, so ATR is considered a promising cancer treatment target. In this study, the antitumor activity of AZ20, a highly efficient ATR selective inhibitor, was investigated on pancreatic cancer cells alone and in combination with gemcitabine. The results in pancreatic cancer cells showed that AZ20 could inhibit cell growth, but had little effect on cell death. AZ20 could inhibit the activity of CHK1-CDC25C-CDK1 signaling pathway downstream of ATR and up-regulate DNA damage. These results suggest that AZ20 has two effects on cell cycle test sites: inhibition of ATR and activation of DNA damage. According to the results that AZ20 can induce arrest of S phase and G 2 / M phase, we infer that the net effect of AZ20 on cell cycle test point is that the activation induced by up-regulation of DNA damage .AZ20 induction of DNA damage will provide a molecular basis for the combination of AZ20 and DNA damage drugs. Gemcitabine has been used for nearly 20 years as a first-line chemotherapeutic agent for pancreatic cancer, but the efficacy of gemcitabine alone is very limited. Because the mechanism of gemcitabine is to induce DNA damage in cells, we try to combine AZ20 with gemcitabine. The results showed that AZ20 could increase the cytotoxicity of gemcitabine, weaken the cell cycle arrest induced by gemcitabine and enhance the cell death induced by gemcitabine. At the same time, AZ20 could increase the DNA damage induced by gemcitabine, inhibit the gemcitabine-activated cell cycle test point and down-regulate the expression of ribonucleotide reductase (RNR) induced by gemcitabine. These results suggest that AZ20 upregulated gemcitabine-induced DNA damage by inhibiting the DNA repair function of ATR, promoting cell cycle operation and decreasing RNR activity, and then increased the cell death induced by gemcitabine. To sum up, the present study proves that AZ20 can enhance the activity of gemcitabine in killing pancreatic cancer cells. It is pointed out that targeting ATR to increase the anti-pancreatic cancer activity of DNA-damaging drugs is an effective and feasible therapeutic strategy. The research in this paper lays a solid experimental foundation for the clinical application of AZ20 and provides a new idea for the clinical treatment of pancreatic cancer.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：R735.9
【相似文献】
相关硕士学位论文 前1条
1 任启航;AZ20增强吉西他滨杀伤胰腺癌细胞活性的研究[D];吉林大学;2016年
，本文编号：2135557
本文链接：https://www.wllwen.com/yixuelunwen/zlx/2135557.html
