Supporting Effect of Umbilical Cord Blood-Derived Mesenchymal Stem Cells on CD34+ Cell Proliferation and Its Mechanism / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the ability of UCB-derived MSCs to support the expansion of HSCs ex vivo and the possible mechanisms involved in this process.</p><p><b>METHODS</b>HSCs from UCB were co-cultured with UCB-derived MSCs for 14 days, and then the total number of HSCs and colony-forming units (CFU) were detected. Cytokines levels of MSCs supernatant were analyzed using ELISA.</p><p><b>RESULTS</b>The proliferation rate of HSCs co-cultured with MSCs was significantly higher than that of cultured HSCs alone (P<0.05). Furthermore, the addition of exogenous cytokines to the culture system significantly increased the proliferation rate of HSCs (P<0.05). MSCs had secretion of many cytokines, including GM-CSF, IL-7, IL-8, IL-11, SCF and SDF-1α.</p><p><b>CONCLUSION</b>UCB-derived MSCs as a feeder layer can be an alternative approach for ex vivo expansion of HSCs, and the cytokines by secreted UCB-MSCs may mediate the supportive role of MSC to HSC proliferation.</p>

Inducing-apoptosis effect of bortezomib on acute monocytic leukemia cell SHI-1 and its influence on expressions of Bcl2l12, Bcl-2 and Bax genes / 中国实验血液学杂志

This study was aimed to explore the effect of bortezomib on proliferation and apoptosis of acute monocytic leukemic cells SHI-1 and the function of Bcl-2 gene family including Bcl2l12, Bcl-2 and Bax in its apoptosis. SHI-1 cells were cultured and treated with bortezomib of different concentrations for different time. MTT assay was used to detect the proliferation and apoptosis, Annexin-V staining, mitochondrial transmembrane potential (DeltaPsim) and DNA aga-rose gel electrophoresis were used to investigate apoptosis of SHI-1 cells. RT-PCR was used to analyze the levels of Bcl2l12, Bcl-2 and bax mRNA in SHI-1 cells treated with bortezomib for 0, 6, 12 and 24 hours. The results showed that bortezomib inhibited the proliferation of SHI-1 cells in time-and doze-dependent manners, the IC(50) at 24 and 48 hours were 54.13 nmol/L and 5.45 nmol/L respectively. Bortezomib could induce apoptosis of SHI-1 cells in time-dependent manner, increase expression of Annexin-V positive cells, decrease DeltaPsim of SHI-1 cells and result in DNA fragmentation and morphologic changes of apoptosis. RT-PCR showed that Bcl2l12 mRNA expression was up-regulated, bcl-2 mRNA expression was down-regulated and bax mRNA expression was not changed obviously. It is concluded that bortezomib inhibits the proliferation of SHI-1 and induces apoptosis in which Bcl2l12 and Bcl-2 gene can be ones of the main genes taking part in.