西地那非在小鼠结肠炎相关性癌变中的作用及机制研究

发布时间：2018-06-26 01:33

本文选题：结直肠癌 + 结肠炎　；参考：《南方医科大学》2017年博士论文

【摘要】：研究背景近年来,越来越多的研究关注肿瘤微环境对肿瘤发生、发展的作用,结果表明肿瘤微环境的变化在肿瘤(包括结直肠癌)的发生、发展中扮演着重要角色。免疫和炎症是构成肿瘤微环境的两大核心,但两者之间关系并不十分清楚,结直肠癌中也是如此。既往研究显示结肠炎症与肿瘤之间有着密切的联系,炎症性肠病(包括溃疡性结肠炎与克罗恩病)患者比健康人群有着更高的患癌率。在炎症环境下,反复上演着组织破坏与再生及氧化应激损伤。在这一过程中,基因突变可能被激活,从而促进了肿瘤的发生。此外,炎性细胞因子的持续存在,可能导致过度的细胞增殖与存活,从而从另外一个方面启动了癌变进程。有研究表明髓源性抑制细胞(MDSCs)的聚集在这一过程中发挥了重要作用。磷酸二酯酶(phosphodiesterase,PDE)是一个多基因的大家族,在人体内分布广泛,参与了多种细胞活动。家族成员PDE-5存在于多种组织中,它的作用是调控一氧化氮的第二信使环磷酸鸟苷。有动物实验证实PDE-5抑制剂能够预防三硝基苯磺酸、醋酸等诱发的大鼠结肠炎,同样也可以预防大鼠的缺血性结肠炎。然而,在炎症相关的结肠肿瘤模型中,PDE-5的表达情况及其作用尚不明确,PDE-5与结肠炎相关性结肠肿瘤的发生是否相关等问题有待于进一步研究。研究目的本研究拟建立结肠炎、结直肠癌及结肠炎相关性结直肠癌三种小鼠模型,探讨PDE-5是否与小鼠结肠炎相关性结直肠癌的发生有关,其抑制剂西地那非是否能够抑制小鼠结肠炎及结肠炎相关的癌变,并探讨其作用机制,为炎症相关性结直肠癌的防治提供新的思路。研究方法分别以葡聚糖硫酸钠(DSS)、氧化偶氮甲烷(AOM)及AOM+DSS诱导建立小鼠结肠炎、结直肠癌及结肠炎相关性结直肠癌模型。建模过程中,对照组与实验组分别以生理盐水及西地那非进行干预,观察各模型中2组小鼠的结肠炎症及成瘤情况,并采用ELISA、Western blot等方法检测2组的PDE-5表达情况;以流式细胞术检测炎症情况;以基质胶侵袭实验检测西地那非对肿瘤发生的抑制是否通过抑制MDSCs的募集来实现。研究结果PDE-5在3组模型中均高表达,抑制PDE-5(西地那非)可以抑制小鼠结肠炎症及结肠炎相关的癌变,但不能抑制AOM直接诱导的结直肠癌的发生。西地那非可以抑制MDSCs的迁移,但不能直接抑制巨噬细胞的迁移。研究结论西地那非不能直接抑制小鼠结直肠癌的发生,它的抑癌作用是通过它对炎症的抑制作用来实现的。西地那非是通过抑制MDSCs的募集来发挥其抑制小鼠结肠炎症及炎症相关性癌变作用的。
[Abstract]:In recent years, more and more attention has been paid to the role of tumor microenvironment on the occurrence and development of tumor. The results show that the change of tumor microenvironment plays an important role in the development of tumor (including colorectal cancer). Immunity and inflammation are the two core of tumor microenvironment, but the relationship between them is not very clear, This is also true of colorectal cancer. Previous studies have shown a close association between colitis and tumors. Patients with inflammatory bowel disease (including ulcerative colitis and Crohn's disease) have a higher rate of cancer than healthy people. In the inflammatory environment, tissue destruction and regeneration and oxidative stress damage are repeated. In this process, the gene is in the process. Mutations may be activated and promote the occurrence of tumors. In addition, the persistent presence of inflammatory cytokines may lead to excessive cell proliferation and survival, thus starting the process of cancer from another aspect. Studies have shown that the accumulation of myeloamedullary cells (MDSCs) plays an important role in this process. Phosphodiesterase (Phosp) Hodiesterase, PDE, a large family of polygenes, is widely distributed in the human body and participates in a variety of cell activities. Family members, PDE-5, exist in a variety of tissues, and its role is to regulate the second messenger of nitric oxide, cGMP. Animal experiments have proved that PDE-5 inhibitors can prevent the rats induced by three nitrobenzene sulfonic acid, acetic acid and so on. Colitis can also prevent ischemic colitis in rats. However, in the inflammation related colon tumor model, the expression of PDE-5 and its role are not clear. The problem of the correlation between PDE-5 and colitis related colonic tumors remains to be further studied. Three mice model of colitis related colorectal cancer is used to investigate whether PDE-5 is associated with the occurrence of colorectal cancer associated with colitis in mice. The inhibitor sildenafil can inhibit the carcinogenesis associated with colitis and colitis in mice, and explore its mechanism to provide new ideas for the prevention and treatment of inflammatory related colorectal cancer. Mouse colitis, colorectal cancer and colitis related colorectal cancer were induced by sodium dextran sulfate (DSS), oxidative azo methane (AOM) and AOM+DSS, respectively. In the process of modeling, the control group and the experimental group were treated with saline and sildenafil respectively. The colitis and tumor formation of 2 groups of mice were observed and the tumor formation was observed. ELISA, Western blot and other methods were used to detect the expression of PDE-5 in 2 groups. Flow cytometry was used to detect the inflammation. The inhibition of sildenafil's inhibition of the tumor was detected by inhibition of the recruitment of MDSCs. The results of PDE-5 were highly expressed in the 3 groups of models, and inhibition of PDE-5 (sildenafil) could inhibit mice. The carcinogenesis associated with colitis and colitis can not inhibit the occurrence of AOM directly induced colorectal cancer. Sildenafil can inhibit the migration of MDSCs, but can not directly inhibit the migration of macrophages. Conclusion Sildenafil can not directly inhibit the occurrence of colorectal cancer in mice. Its inhibitory effect is through its inhibition of inflammation. Sildenafil inhibits murine colitis and inflammation associated carcinogenesis by inhibiting MDSCs recruitment.
【学位授予单位】：南方医科大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：R574.62;R735.3

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