STUDY OF THE ROLE OF LEUCINE-RICH REPEAT-CONTAINING G-PROTEIN COUPLED RECEPTOR 5 (LGR5) AND WNT PATHWAY IN COLON CANCER

Leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5) is a marker for intestinal cancer stem cell and is a target gene of the Wnt/β-catenin signaling pathway, which play an important role in carcinogenesis.In the existing study, evaluation of LGR5, β-catenin and c-Myc mRNA expression by real-time PCR were identified in 40 colon cancer tissue samples in addition to 20 sample from the healthy safety margin of colon cancer as a control.The LGR5, β-catenin and c-Myc mRNA expression levels were detected in HT-29 colon cancer cell line after transfection with siRNALGR5.Then the cells were devided in to following groups: first group was not transfected and representing the control, the seconed group was treated with Lipofectamine® RNAiMAX transfection reagent only to exclude the toxic effect of Lipofectamine, the third group was treated with siRNA, the fourth group was treated with 5-Flurouracil Rehab El-Sayed et all ‫ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬ ‫ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬ ‫ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬ ‫ـــــــــ‬ 2 drug and the fifth group was treated with 5-Flurouracil after siRNA treatement.The viability of the cells in all groups were measured by Vybrant MTT Cell Proliferation Assay Kit.LGR5 expression was elevated in colon cancer tissue samples as compared to that of healthy tissues (P<0.05).Also knockingdown ofLGR5 decreased the mRNA expression of β-catenin and c-Myc in HT29 colon cancer cells moreover, decreased the growth rate of HT29 cells and this decline in cell growth was more after combination ofLGR5 and 5-Flurouracil treatement.These results reported that LGR5 expression could be important for CRC cell proliferation and targeting it improves the response to chemotherapy showing that LGR5 may provide new therapeutic strategy for colon cancer.