下调结直肠癌细胞受体酪氨酸激酶样孤儿受体抑制细胞生长并促进其凋亡

Down-regulation of receptor-tyrosine-kinase-like orphan receptor 1 suppresses cell growth and enhances apoptosis in human colorectal carcinoma

目的探讨受体酪氨酸激酶样孤儿受体1(ROR1)在人结直肠癌中的表达及其生物学功能。方法收集60例结直肠癌及对应癌旁组织,实时定量PCR(qRT-PCR)检测ROR1的mRNA水平,免疫组织化学染色检测ROR1的蛋白水平,并分析ROR1蛋白与肿瘤临床病理资料间的相关性。利用ROR1的siRNA特异性敲低结肠癌SW480细胞中ROR1表达,采用qRT-PCR、Western blot法检测ROR1的敲减效果,MTT法检测下调ROR1后,SW480细胞的增殖,异硫氰酸荧光素标记的膜联素Ⅴ/碘化丙啶(annexinⅤ-FITC/PI)双染色结合流式细胞术检测下调ROR1后,SW480细胞的凋亡情况。结果 ROR1在结直肠癌组织中表达水平明显高于对应癌旁组织;结直肠癌组织中ROR1高表达与肿瘤体积增大(≥5 cm)、淋巴结转移及高TNM分期(Ⅲ+Ⅳ期)显著相关;ROR1的siRNA可显著降低SW480细胞ROR1 mRNA及蛋白的水平;下调ROR1表达能够抑制SW480细胞的增殖并促进其凋亡。结论 ROR1在结直肠癌组织中表达上调并与结直肠癌恶性临床病理特征有关,下调ROR1能够抑制结肠癌细胞的生长并促进其凋亡。

Objective To investigate the expression of receptor-tyrosine-kinase-like orphan receptor 1 （ROR1） and its role in cell growth in human colorectal carcinoma （CRC）. Methods Real-time quantitative PCR （qRT-PCR） and immuno- histochemistry （IHC） were used to detect the expression of ROR1 in CRC （n =60） and matched tumor-adjacent tissues. The relationship between the expression of ROR1 and clinical features was analyzed by Pearson chi-square test. siRNA was used to down-regulate the expression of ROR1 in SW480 cells in vitro. The qRT-PCR and Western blotting were performed to confirm the down-regulation of ROR1 expression. The effects of down-regulated ROR1 on cell proliferation and apoptosis were measured by MTT assay and flow cytometry combined with annexin V-FITC/PI staining, respectively. Results Both the mRNA and protein expression of ROR1 were significantly up-regulated in CRC tissues than in tumor-adjacent tissues, and the expression of ROR1 was positively correlated with tumor size （ ≥5 cm）, lymphatic metastasis and TNM stage （Ⅲ and Ⅳ）. siRNA could significantly down-regulate the expression of ROR1 in SW480 cells, then suppressed proliferation and enhanced apoptosis in SW480 cells. Conclusion The expression of ROR1 was significantly higher in CRC tissues than in tumor-adjacent tissues. Down-regulation of ROR1 could play an anti-cancer role through inhibiting proliferation and inducing apoptosis in CRC.