Study On The Effects And Mechanisms Of LukS-PV Induced Differentiation In Human Monocytic Leukemia THP-1 Cell

Objective LukS-PV is one of the two components of PVL. In our previous study, we had confirmed that recombination LukS-PV (rLukS-P V) had the ability of inhibiting proliferation and induction apoptosis in human acute myeloid leukemia (AML) cell line, HL-60 and THP-1 cells. In this study, we investigated the induction differentiation effect of LukS-PV on the human myelomonocytic leukemia THP-1 cell lines and explored its mechanism of effect.Methods THP-1 cells were treated with different concentrations (0,0.50,1.00,1.50 μM) of LukS-PV for 24 and 48h.(1) The morphology of induced cells was observed with Wright-Giemsa staining under optical microscope; (2) Differentiation markers CD 14 and CD11b were detected by flow cytometry,the cell phagocytosis for fluorescent particles was detected by fluorescence microscope; (3) The ability of migration and invasion of THP-1 cells were analyzed by transwell; (4) Phosphorylation of MAPK signaling pathways were analyzed by western blotting, including p-ERKl/2, p-JNK, p-p38, p-c-Fos, p-c-Jun and p-ATF2; (5) THP-1 cells were pretreated with P38 inhibitor,JNK inhibitor,or ERK inhibitor, flow cytometry detected CD 14 and CD11b expression.Results (1)THP-1 cells treated with LukS were changed from dispersal and suspended into adhesive and fusiform. Cell volume and cytoplasm content increased, nucleo-cytoplasmic ratio decreased. The shape of cell nucleus was reniform, triangle and irregular. The cell nucleus were located at the side of cells. (2) The expression of CD11b and CD 14 were significant increased, especially CD 14. The cell phagocytosis for fluorescent particles was also obviously enhanced. The above effects both in a dose-and time-dependent manner. (3) Treatment with LukS-PV, the ability of migration and invasion of THP-1 cells were significant increased. (4) Treatment with LukS-PV, the levels of p-ERK1/2, p-JNK, p-p38, p-c-Fos, p-c-Jun and p-ATF2 increased significantly.(5) Pretreatment with P38 inhibitor, JNK inhibitor, or ERK inhibitor, the expression of CD11b and CD14 were significant decreased, and ERK inhibitor is most effective.Conclusion (1) LukS-PV has the differentiation effect of inducing THP-1 cell lines into monocyte-macrophages system. (2) LukS-PV has the effect of inhibition migration and invasion of THP-1 cells. (3) LukS-PV can induce THP-1 cell differentiation via the ERK,JNK,p38 pathway. And ERK MAPK pathway is the main pathway regulated the differentiation effect of LukS-PV in THP-1 cell.