结直肠癌组织中巨噬细胞表达胸苷磷酸化酶并与血管新生相关

Thymidine phosphorylase expression by macrophage in colorectal carcinoma and its relationship with tumor angiogenesis

目的探讨结直肠癌组织中胸苷磷酸化酶(dThdPase)表达与血管新生的相互关系。方法采用抗dThdPase、抗巨噬细胞标记物CD68和抗血管内皮细胞标记物CD34的单克隆抗体,对40例结直肠癌手术切除标本进行免疫组织化学染色分析,对其中27例标本同时测定其癌组织和周围正常组织的dThdPase活性(HPLC法)。并应用ELISA法分别检测结直肠癌细胞系LS174T、CloneA、Colo320、CX-1、Lovo、MIP101和类巨噬细胞系THP-1和U937的dThdPase蛋白含量。结果结直肠癌组织中的dThdPase活性明显高于周围正常肠组织(P<0.01)。dThdPase阳性细胞几乎都是癌巢周围的间质细胞,特别是肿瘤相关巨噬细胞(TAM)。且TAM与dThdPase阳性细胞的分布区域几乎完全一致。癌巢周围新生血管数明显多于正常肠黏膜组织(P<0.01)。TAM计数、dThdPase阳性间质细胞计数和微血管计数3者互成正相关。除LS174T检出微量和Lovo检出少量dThdPase蛋白外,其他4株癌细胞未检出。而THP-1和U937的dThdPase蛋白含量分别为18.2U/mg和19.3U/mg。结论结直肠癌组织中增高的dThdPase活性主要由TAM表达,增多的TAM与结直肠癌的血管新生相关。

Objective To investigate thymidine phosphorylase (dThdPase) expression in colorectal carcinoma and its relationship with tumor angiogenesis. Methods Resected samples from 40 patients with colorectal carcinoma were immunohistochemically stained by monoclonal antibodies 654 1 (anti dThdPase),PG M1(anti macrophage marker CD68),and NU A1 (anti endothelial cell marker CD34). In addition, dThdPase activity analysis was also performed by HPLC in cancer and para tumor tissues from 27 cases. dThdPase levels were also detected by ELISA in 6 colorectal cancer cell lines, such as LS174T, Clone A, Colo320, CX 1, Lovo, MIP101 and 2 macrophage like cell lines, THP 1, U937. Results The activities of dThdPase were significantly higher in cancer tissues than those in normal colon tissues (P< 0 01). Almost all of dThdPase positive cells were stromal cells, such as macrophage, fibroblasts, lymphocytes, etc., and located around cancer nests, or between the cancer nests and normal tissues. The distribution patterns of dThdPase positive stromal cells were similar to those of CD68 positive cells. The microvessel counts in cancer tissues were significantly higher than those in normal adjacent colon tissues (P< 0 01). Furthermore, the numbers of dThdPase positive cells were correlated with both TAMs and microvessel counts in the relevant areas. The dThdPase levels were 0 5 and 8 9 U/mg in LS174T and Lovo lines, respectively, but not detected in other 4 colorectal cancer cell lines. The dThdPase levels were 18 2 and 19 3 U/mg in THP 1 and U937 lines respectively. Conclusions TAM is a major source of dThdPase activity, and cancer cells in colorectal carcinoma tissues are not. Increased TAMs may be related to angiogenesis in cancer tissues.