The Effect Of Camptothecin On Mouse Bone Marrow Neutrophils

ObjectiveTo investigate the effect of camptothecin on the expression of XIAP,TLR4,CXCR2 mRNA and the apoptosis of neutrophils in bone marrow of normal mice and the expression of NE,MMP9 and CXCR2 protein in bone marrow of mice with breast cancer.MethodBy Fluorescence quantification PCR technique,we measured the expression of XIAP,TLR4,CXCR2 mRNA in bone marrow neutrophils of normal mice treated with different concentrations of camptothecin for 1 hour.The apoptosis of bone marrow neutrophils in mice treated with different concentrations of camptothecin for 1 hour was measured by Annexin V-FITC/PI double staining using flow cytometry.Breast cancer mouse models were established using TUBO mouse breast cancer cells and then treated with camptothecin.The expression of NE,MMP9 and CXCR2 protein in bone marrow of mice with breast cancer were measured by using Western Blot.ResultsThe expression of XIAP,TLR4 and CXCR2 mRNA in normal mice treated with different concentrations of camptothecin for 1 hour was detected by fluorescence quantitative PCR.The results showed that the expression of XIAP,TLR4 and CXCR2 mRNA in bone marrow neutrophils decreased after 1 hour of camptothecin treatment,compared with the blank group.When the camptothecin concentration was 2 u M and 20μM,the decline was the most obvious,the difference was statistically significant.Apoptosis of bone marrow neutrophils in mice treated with different concentrations of camptothecin for 1 hour was measured by Annexin V-FITC/PI double staining using flow cytometry.The results showed that bone marrow neutrophils did not show significant apoptosis after one hour of treatment with camptothecin at 200 nM,2μM,20μM.The apoptotic rate of cells increased slightly with the increase of camptothecin concentrationThe expression of NE,MMP9 and CXCR2 protein in bone marrow neutrophils of breast cancer mice treated with camptothecin was detected by Western Blot technique.The results showed that the expression of NE,MMP9 and CXCR2 protein in bone marrow neutrophils of breast cancer mice treated with camptothecin were decreased compared with the untreated model group.ConclusionsCamptothecin can down-regulate the expression of XIAP,TLR4 and CXCR2 mRNA in normal bone marrow neutrophils without significant apoptosis.The decrease of XIAP gene expression by camptothecin can promote the apoptosis of neutrophils.Camptothecin down-regulation of TLR4 gene expression of neutrophils can inhibit the stimulation of neutrophils by LPS and inhibit neutrophils release from the bone marrow to reach the inflammatory site.The expression of CXCR2 gene by camptothecin can inhibit the stimulation of bone marrow neutrophils by chemokines and inhibit the release of neutrophils from bone marrow..The decrease of NE and MMP9 protein by camptothecin reduces the effect of neutrophils entering the tumor site to participate in the external matrix remodeling of tumor cells to promote tumor proliferation.Camptothecin down-regulates the expression of CXCR2 protein,which reduces the number of neutrophils that are released from the bone marrow into the tumor site by stimulation with chemokines and inhibits the role of neutrophils to promote tumor growth.