Influence of BMP4 on Regulation of Cell Cycle and Apoptosis of Hematopoietic Stem Cells/Progenitor Cells and Its Mechanism in Chemotherapy-Induced Myelosuppression / 中国实验血液学杂志

OBJECTIVE@#To explore the effect of bone morphogenetic protein 4(BMP4) on the cell cycle and apoptosis of hemaropoictic stem and progenitor cells (HSPC) in conditions of 5-fluorouracil (5-FU)-inducing bone marrow suppression and stress hemogenesis, and its possible mechanism.@*METHODS@#The C57BL transgenic mice with BMP4 overexpression were established and were enrolled in transgenic group (BMP4 group), at the same time the wild type mice matching in age, sex and body weight were selected and were enrolled in control group (WT group). The bone marrow suppression was induced by injection with 5-FU in dose of 150 mg/kg, then the nucleated cells were isolated from bone marrow. After the HSPCs were markered with C-kit/sca-1 fluorescent antibodies, the changes of cell cycle and apoptosis of HSPC were detected by Aunexin V/PI and Ki67/DAPI double staining; the cell cycle-essociated hemotopoietic regulatory factors were detected by RT-qPCR.@*RESULTS@#Under physiologic status, there were no significant differences in cell cycle and apoptotic rate of HSPC between WT group and BMP-4 group. After the bone marrow was suppressed, the ratio of HSPC at G0 phase in BMP4 group significantly decreased(P＜0.05); the apoptosis rate of HSPC significantly increased(P＜0.05); the mRNA expression levels of hypoxia-inducing factor Hif-1α and chemotactic factor CXCL12 in stroma of BMP4 group were down-regulated significanfly(P＜0.05).@*CONCLUSION@#Under non-physiologic conditions such as stress hemogenesis or bone marrow suppression, the up-regulation of BMP4 can promote HSPC into cell cycle and apoptosis of HSPC, moreover, the BMP4 may play a regulatory role for cell cycle of HSPC through direct or indirect down-regulation of Hif-1α and CXCL-12 expressions.

Imperatorin enhances anti-tumor effect of TRAIL on breast cancer by upregulating expression of DR5 on cell surface / 中国病理生理杂志

AIM:To investigate the synergistic effect of imperatorin on enhancing the anti -tumor effect of TNF-related apoptosis-inducing ligand(TRAIL)on breast cancer and the mechanisms.METHODS:T-47D and MCF-7 breast cancer cells were divided into control group ,imperatorin group,TRAIL group,imperatorin+TRAIL group and imperatorin+TRAIL+death receptor 5(DR5)siRNA group.The viability of T-47D and MCF-7 cells was measured by MTT assay. The apoptosis and mitochondrial membrane potential in T-47D cells were analyzed by flow cytometry.Western blot and flow cytometry analysis were performed to evaluate the expression of DR 5 on T-47D cell surface and the activation of caspase-8 and caspase-3.RESULTS:Imperatorin significantly enhanced the inhibition of cell viability induced by TRAIL of T -47D and MCF-7 cells,and significantly increased the apoptosis of T-47D cells induced by TRAIL.Imperatorin treatment ob-viously induced upregulation of DR5 expression and production of reactive oxygen species in the T-47D cells.In addition,imperatorin enhanced the TRAIL-induced damage of mitochondrial membrane potential and activation of caspase -8 and caspase-3.CONCLUSION:Imperatorin enhances the anti-tumor effect of TRAIL on breast cancer via upregulating the ex-pression of DR5.