Study on mechanism of telomere system regulation and senescence induction of leukemia stem cells by Angelica sinensis polysaccharide / 中草药

ABSTRACT

Objective: To investigate the mechanisms on the regulation of telomere and telomerase in the process of senescence induction of human-derived CD34+CD38- leukemia stem cells (LSC) subpopulation by Angelica sinensis polysaccharide (ASP). Methods: The human-derived CD34+CD38- LSC subpopulation was isolated from acute myelogenous leukemia bone marrow mononuclear cells by magnetic activated cell sorting. The inhibition of ASP on CD34+CD38- LSC subpopulation proliferation was detected by CCK-8 assay. The percentage of senescent cells was detected by SA-β-Gal staining. The colony-formed ability was detected by Colony-forming Assay. The levels of telomerase activities and telomerase reverse transcriptase (TERT) gene expression were performed by TRAP-PCR and quantitative RT-PCR, respectively. The changes of telomere length were tested by Southern blotting assay. Results: The CD34+CD38- LSC subpopulation could be effectively isolated by MACS. The purity of CD34+CD38- LSC population is up to (91.15 ± 2.41)%; The cells showed the features of well-stacked morphology, high transparency, well refraction under inverted phase contrast microscope. ASP had a remarkable dose-dependent inhibition on CD34+CD38- LSC proliferation in vitro culture (P < 0.05). The number of SA-β-Gal staining positive cells had been increased compared to the cells in control group (P < 0.01), a decrease in colony-forming abilities (P < 0.01), a decrease level on TERT gene and telomerase activities (P < 0.05), and a shorter length on telomere of CD34+CD38- LSC after 40 μg/mL ASP co-culture for 48 h (P < 0.05). Conclusion: ASP could induce the senescence of human derived leukemia bone marrow CD34+CD38- LSC via regulating the cell telomere system in vitro co-culture.