RNAi-mediated Silencing of CXCR4 Inhibits the Adhesion, Invasion and Tumorigenicity of Acute Monocytic Leukemic Cell Line SHI-1

Abstract

To investigate the effect of CXCR4 gene on the proliferation, adhesion, invasion and tumorigenicity of a human monocytic leukemic cell line SHI-1. The lentivirus vector silencing the expression of CXCR4 was constructed for infection of SHI-1 cells silencing expression of CXCR4 in SHI-1 cells. The expression of CXCR4, MMP-2 and MMP-9 was detected by real time PCR. The expression of CXCR4 on membrane of SHI-1 cells was detected by flow cytometry. The SHI-1 cell proliferation ability was detected by MTT. The co-culture system of the leukemia cells and bone marrow stromal cells was used to detect the adhesion and migration ability of leukemia cells. SHI-1 cells were inoculated subcutaneously in nude mice to investigate the growth ability in vivo. After SHI-1 cells were infected by lentivirus silencing expression of CXCR4, the expression of CXCR4 mRNA in SHI-1 CXCR-4i cells decreased by 76% as compared with expression of SHI-1/NC of negative control virus, the expression of CXCR4 on membrane of SHI-1/CXCR4i obviously downregulated; the expression of MMP-2 and MMP-9 in SHI-1/CXCRi cells also declined by 63% and 62% respectively; the proliferation ability of SHI-1/CXCR4i in vitro did not obviously changed, but the adhesion and trans-matrigel invasion ability significantly decreased, the SHI-1/CXCR4i cells could not form neoplasm subcutaneously in mice, but the SHI-1 and SHI-1/NC cells could form neoplasm subcutaneously in mice, and there was no significant difference in volumn of neoplasm mass. The silencing expression of CXCR4 can decline the adhesion and migration ability of SHI-1 cells, and can completely suppress the formation of neoplasm subcutaneously, so the CXCR4 may serve as a target for treating leukemia.