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

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 immunohistochemistry (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.