A Study on the Mechanism of Low-Expressed Cancer Stem Cell Marker Lgr5 in Inhibition of the Proliferation and Invasion of Colorectal Carcinoma

The present study intends to explore the influence of Lgr5 as a marker of tumor stem cells after siRNA interference on the proliferation and invasion of colorectal carcinoma (CRC) and its mechanism. The tissue samples were taken for biopsy from 32 cases of patients and 32 cases of normal subjects by colonoscopy. Real-time quantitative PCR was used to detect the differential expression of Lgr5. After siRNA interference of Lgr5 in CRC cell line CT-26 cells, RT-PCR method was used to detect the mRNA expression level of Lgr5 after interference of CT-26 cells. CCK8 method was used to observe the influence of Lgr5 interference on the proliferation, colony formation, and invasion of CT-26 cells. RT-PCR and Western blot were used to detect the E-cadherin mRNA and protein levels in CT-26 cells. Lgr5 expression level in CRC tissue was significantly higher than that in the corresponding para-carcinoma tissue and the control group, and the differences were statistically significant ( P < 0.05). Lgr5 mRNA expression level in tissue with lymph node metastasis was significantly higher than that in the tissue without lymph node metastasis, and the difference was statistically significant ( P < 0.05). Compared with the control group, CT-26 cell proliferation, colony formation, and migration capability after Lgr5 siRNA transfection were all significantly reduced, and the differences were statistically significant ( P < 0.05). CT-26 cells after Lgr5 interference were found with significantly reduced E-cadherin mRNA and protein levels. Lgr5 facilitates the cell proliferation, colony formation, and migration of colorectal carcinoma, which may be closely related to the expression level of E-cadherin.