[Screening and Verification of Antioxidant Small Molecular Compounds for Expansion of Human Hematopoietic Stem Cells Ex Vitro].

OBJECTIVE: To screen the antioxidant small molecular compounds with optimal efficiency of expansing the human hematopoietic stem cells (hHSC) In vitro based on antioxidant small molecular compound database of LKT laboratory, and to verify the effects of these compounds on the biological functions of hHSC. METHODS: The umbilial cord blood CD34+ cells were enriched by using the MACS beads; the absolute number and percentage of CD34+ cells and CD34+ CD49f+ cells were detected by high throughput flow cytometry after culture of hHSC with compounds in vitro for 1 week, the SR1 (1 µmol/L) was used as positive control, the candidate compounds were screened out; then 4 compounds were selected for follow-up experiments by comprehensive evaluation of concentration, safety and expansion efficacy, the optimal used concentrations of selected compounds were determined through the concentration gradient analysis, and CFC short-term colony-forming cell test was performed by using the determined concentration so as to verify the effect of compounds on the self-renewal, multilineage differentiation. RESULTS: Out of 85 antioxidant small molecular compounds, 4 compounds (C2968, D3331, B1753 and B3358) with obvious expansion efficacy for CD34+ cells and CD34+ CD49f+ cells were screened out by high throughput flow cytometry; their optimal concentrations of 4 compounds were 0.5 µmol/L for C2968, 1.5 µmol/L for D3331 and 1.5 µmol/L for B1753 and 15 µmol/L for B3358. The CFC assay showed the colony formation number in compound-treated group significantly increased as compared with control group, moreover the self-renewal and multilineage differentiation were maintained. CONCLUSION: The antioxidant small molecular compounds C2968 (0.5 µmol/L), D3331 (1.5 µmol/L), B1753 (1.5 µmol/L) and B3358 (1.5 µmol/L) possess good expansion efficacy for hHSC, they can maintain hHSC self-renewal, at the same time ensure the multilineage differentiation potentiality of hHSC.

Antineoplastic effects and mechanisms of micheliolide in acute myelogenous leukemia stem cells.

Leukemic stem cells (LSCs) greatly contribute to the initiation, relapse, and multidrug resistance of leukemia. Current therapies targeting the cell cycle and rapidly growing leukemic cells, including conventional chemotherapy, have little effect due to the self-renewal and differentiated malignant cells replenishment ability of LSCs despite their scarce supply in the bone marrow. Micheliolide (MCL) is a natural guaianolide sesquiterpene lactone (GSL) which was discovered in michelia compressa and michelia champaca plants, and has been shown to exert selective cytotoxic effects on CD34+CD38- LSCs. In this study, we demonstrate that DMAMCL significantly prolongs the lifespan of a mouse model of human acute myelogenous leukemia (AML). Mechanistic investigations further revealed that MCL exerted its cytotoxic effects via inhibition of NF-κB expression and activity, and by generating intracellular reactive oxygen species (ROS). These results provide valuable insight into the mechanisms underlying MCL-induced cytotoxicity of LSCs, and support further preclinical investigations of MCL-related therapies for the treatment of AML.

[Ex vivo Culture System of Single Human Hematopoietic Stem Cell Used to Screan the Small Molecular Compounds].

OBJECTIVE: To explore an efficient, stable system and method to verify the regulation effect of small molecule compounds on human hematopoietic stem cells (hHSC). METHODS: By using combination of flow cytometry with study results of surface markers on hHSC, and optimation of sorting process for further studying the effect of small molecular compounds on stem property of hHSC, the single hHSC was treated with published small molecular compounds such as SR1 and UM171 which possess the expansion effect. After treating with hHSC for 14 d, the flow cytometric analysis of cell phenotypes and cell morphologic observation were performed, at the same time the hematopoietic function of cultured hHSC was verified by colony-forming cell (CFC) test and cobblestone area forming cell (CAFC) test. RESULTS: The effects of SR1 and UM171 and their compositions in multi-cell culture were consistent with the published data, therefore the useful concentration of compounds were obtained. The results of multiparameter sorting of single cell (CD34+ CD38- CD45RA- CD90+ CD49f+) and ex vivo culture were consistent with the results of bulk cell culture. The results of cell phenotype analysis was in accordance with flow cytometric results. In addition, CFC test and CAFC test revealed that the colony-forming ability in treated group was significantly higher than that in control group (P<0.05). CONCLUSION: The rapid, efficient stably amplified and short-time culture system for single hHSC and method for varifying the effect of small molecular compounds are established, which provides platform for screening small molecular compounds and lays the foundation for further study of hHSC expansion.