Ginsenoside Rk3 Inhibits the Extramedullary Infiltration of Acute Monocytic Leukemia Cell via miR-3677-5p/CXCL12 Axis

BACKGROUND: Acute monocytic leukemia belongs to type M5 of acute myeloid leukemia (AML) classified by FAB, which appears a high incidence of extramedullary infiltration (EMI) and poor prognosis. In this study, we observed the inhibitory effect of ginsenoside Rk3 on the EMI of monocytic leukemia cells and initially explored its related mechanism of targeting the miR-3677-5p/CXCL12 axis. METHODS: The MTT assay and colony formation assay were used to detect the inhibitory effect of Rk3 on proliferation. Both cellular migration and invasion were observed by the Transwell assay. The expression levels of miR-3677-5p, CXCL12, and CXCR4 were detected by RT-qPCR and Western blot, as well as overexpression of miR-3677-5p by transfected with lentivirus and detection of a dual luciferase reporter gene. The expression of MMP2 and TIMP2 was detected by immunofluorescence. RESULTS: Rk3 effectively inhibits the proliferation, migration, and invasion associated with EMI of leukemia. The leukemia cells of M5 patients with EMI showed low expression of miR-3677-5p but high expression of the mRNA of CXCL12 and CXCR4. Overexpression of miR-3677-5p or intervention of CXCL12 effectively inhibited the proliferation, migration, and invasion of SHI-1 cells. The luciferase assay showed that CXCL12 was the downstream target gene of miR-3677-5p. After overexpression of miR-3677-5p or intervention of CXCL12 in combination with Rk3, the inhibitory effect on the proliferation, migration, and invasion of SHI-1 cells was more obvious. Importantly, Rk3 significantly regulated the expression levels of miR-3677-5p, CXCL12, CXCR4, and EMI-related functional proteins including MMP2 and TIMP2. Overexpression of miR-3677-5p or intervention of CXCL12 also regulated the expression of MMP2 and TIMP2. CONCLUSIONS: The leukemia cells of M5 patients with EMI appeared to have low expression of miR-3677-5p and high expression of the mRNA of CXCL12 and CXCR4, which may be used as indicators of EMI and poor prognosis. Rk3 is effective in inhibiting the EMI of SHI-1 cells by targeting the miR-3677-5p/CXCL12 axis.