scholarly journals Cardiac Induction of Embryonic Stem Cells by a Small Molecule Inhibitor of Wnt/β-Catenin Signaling

2010 ◽  
Vol 6 (2) ◽  
pp. 192-197 ◽  
Author(s):  
Hanmin Wang ◽  
Jijun Hao ◽  
Charles C. Hong
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Small Molecule ◽  
Embryonic Stem ◽  
Small Molecule Inhibitor ◽  
Molecule Inhibitor

scholarly journals Dorsomorphin, a Selective Small Molecule Inhibitor of BMP Signaling, Promotes Cardiomyogenesis in Embryonic Stem Cells

PLoS ONE ◽  
2008 ◽  
Vol 3 (8) ◽  
pp. e2904 ◽  
Author(s):  
Jijun Hao ◽  
Marie A. Daleo ◽  
Clare K. Murphy ◽  
Paul B. Yu ◽  
Joshua N. Ho ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Small Molecule ◽  
Embryonic Stem ◽  
Small Molecule Inhibitor ◽  
Bmp Signaling ◽  
Molecule Inhibitor

scholarly journals An optimized small molecule inhibitor cocktail supports long-term maintenance of human embryonic stem cells

2011 ◽  
Vol 2 (1) ◽  
Author(s):  
Hideaki Tsutsui ◽  
Bahram Valamehr ◽  
Antreas Hindoyan ◽  
Rong Qiao ◽  
Xianting Ding ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Small Molecule ◽  
Human Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Small Molecule Inhibitor ◽  
Molecule Inhibitor ◽  
Term Maintenance

QLT0267, a Small Molecule Inhibitor of ILK and FLT3 Is Cytotoxic to Acute Myeloid Leukemia (AML) ‘Stem Cells’ Detected in Immunodeficient Mice.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 950-950
Author(s):  
Andrew L Muranyi ◽  
Shoukat Dedhar ◽  
Donna E. Hogge
Keyword(s):  
Stem Cells ◽  
Small Molecule ◽  
Cell Cycle Progression ◽  
Small Molecule Inhibitor ◽  
Mouse Bone Marrow ◽  
Immunodeficient Mice ◽  
Akt Phosphorylation ◽  
Molecule Inhibitor ◽  
Integrin Linked Kinase

Abstract The phosphatidylinositol-3-kinase (PI-3K) and FMS-like tyrosine kinase 3 (FLT3) receptor signaling pathways are constitutively active in many AML blast samples suggesting these as therapeutic targets. Integrin linked kinase (ILK) is involved in Akt and GSK3 activation, key downstream effectors of the PI-3K pathway, and participates in the regulation of apoptosis, cell cycle progression, and tumour angiogenesis in many solid tumours. ILK is also expressed ubiquitously in AML blasts. In previous experiments to explore the effect of targeting ILK in AML, QLT0267, a small molecule inhibitor of ILK, was shown to be cytotoxic to AML blasts and colony forming cells (CFC) from some patient samples. Since AML samples containing the FLT3 internal-tandem duplication (ITD) were more susceptible to QLT0267-induced cell kill than FLT3 wildtype (WT) cells we tested the possibility that QLT0267 could inhibit FLT3 as well as ILK. In vitro kinase assays from 4 AML samples showed that QLT0267 produces equivalent inhibition of ILK and FLT3 (both WT and ITD) while Western blotting of 2 AML samples cultured with QLT0267 showed a dose and time dependant decrease in both FLT3 and Akt phosphorylation. 5 AML samples (4 FLT3-ITD, 1 FLT3 WT), were cultured for 24 h ± QLT0267, and assayed for AML CFC or 6-week suspension culture initiating cells (SC-IC). The mean percents kill for 20 and 50 μM QLT0267, respectively, were 92%, and 100% for AML-CFC and 71% and 92% for SC-IC. CD34+CD38− blasts (enriched for AML cells which engraft in immunodeficient mice) from these same samples were analyzed for expression of ILK, pGSK3, and FLT3. Intracellular staining detected ILK and pGSK3 protein in CD34+CD38− cells at levels similar to those present in other AML cell populations. QRT-PCR showed FLT-3 expression in CD34+CD38− cells from all 5 AML samples with 2 of these showing higher expression in this population than in the remainder of AML blasts. To determine if simultaneous targeting of ILK and FLT3 would kill AML progenitors that engraft in mice 4 AML samples (FLT3-ITD +) were cultured for 24 h ± QLT0267, and then injected IV into sublethally irradiated NOD/SCID or NOD/SCID IL2γRnull mice. As shown in the Table, treatment with 20 μM QLT0267 significantly reduced AML engraftment for 3 of 4 samples while the 50 μM dose was effective for 2 of the 3 samples tested (p<0.05, student t-test). Thus, combined targeting of ILK and FLT3 will kill AML cells, including candidate leukemic stem cells that sustain long-term engraftment in mice. Further preclinical evaluation of the potential therapeutic usefulness of this strategy is ongoing. QLT0267 (μM) 0 20 50 AML Sample % engraftment ± SD AML cells in mouse bone marrow
 Week 16 (n=) 1 86 ± 11
 (4) 53 ± 30
 (6) 2 ± 3
 (4) 2 46 ± 45
 (5) 3 ± 5
 (6) 0
 (2) 3 47 ± 40
 (5) 1 ± 2
 (4) 0
 (6) 4 90 ± 14
 (3) 1 ± 1
 (3) ND

Rapid Mobilization of Long Term Repopulating Hematopoietic Stem Cells (HSC) with AMD15057, a Small Molecule Inhibitor of VLA4; Synergism with AMD3100 and G-CSF

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 615-615 ◽  
Author(s):  
Pablo A. Ramirez ◽  
Michael Rettig ◽  
Matthew Holt ◽  
Julie Ritchey ◽  
John F. DiPersio
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Small Molecule ◽  
Mononuclear Cells ◽  
Optimal Dose ◽  
Small Molecule Inhibitor ◽  
Jurkat Cells ◽  
Hematopoietic Stem ◽  
Molecule Inhibitor

Abstract Background: Hematopoietic stem cells (HSC) interact with stromal cells, osteoblasts and matrix proteins in the hematopoietic niche. This interaction plays an important role in HSC trafficking, proliferation and differentiation. Significant data support the roles of both the SDF-1/CXCR4 and the VCAM1-VLA-4 axes in stem cell homing and mobilization. Two recent reports have shown that Natalizumab, an anti-VLA-4 monoclonal antibody used in the treatment of Multiple Sclerosis, induces mobilization of CD34+ HSC over several days. In the present study we tested the specificity and efficacy of a novel VLA-4 small molecule inhibitor, AMD15057, in murine preclinical studies of normal HSC mobilization. Methods: Fibronectin adhesion assays were performed with Jurkat cells to test the specificity of AMD15057. Ninety-six well plates were coated with fibronectin or BSA and the inhibition of Jurkat cell (VLA-4 +) adhesion by AMD15057 was determined in the presence or absence of PMA activation. To evaluate the mobilization of HSC progenitors, 8 week old 129/B6 F1 mice (n=6 per group, 3 experiments) were left untreated (unmobilized) or treated with AMD15057 (0.1,1,3 mg/kg iv or 3,5,7 mg/ kg sc), AMD3100 (1,3 mg/kg iv or 1,3,5 mg/kg sc), G-CSF (250 mg/kg/d × 5 d) or combinations. Total WBC and CFU-GM were determined at different time points for each mobilization regimen. For long-term competitive repopulation cell assays (LTRC), PBMCs from 3 Ly5.2+ unmobilized or mobilized mice (700uL PB each) were pooled, mixed with 5×105 Ly5.1+ BM mononuclear cells (MNC) (3:1 ratio) and injected into lethally irradiated Ly5.1+/Ly5.2+ compound heterozygote recipient mice. Chimerism was evaluated monthly for 6 months by flow cytometry. Secondary transplants to evaluate long term repopulation activity was performed by injecting lethally irradiated heterozygotes with 106 BM pooled MNC from the primary recipients. Results: The adhesion of untreated and PMA treated Jurkat cells to fibronectin coated wells was decreased by 62% (3.2 SD) and 69% (3.4 SD) (p&lt;0.001) respectively, upon the addition of 1ug/ml AMD15057 compared to vehicle control. In vivo, a single iv or sc injection of AMD15057 resulted in maximum mobilization of CFU-GM within 0.5–0.75 hr. This effect was dose dependent for both sc and iv administrations. Maximum and comparable peak mobilization (13-fold iv; 9-fold sc, pNS) and kinetics of murine HSC mobilization was seen in mice receiving 1mg/kg iv and 5mg/kg sc AMD15057. In contrast, iv dosing of a small molecule inhibitor of CXCR4, AMD3100 (3mg/kg optimal dose) resulted in more rapid peak mobilization (10-fold) in &lt;1hr compared to 3hr peak mobilization (20-fold) after sc dosing (5mg/kg optimal dose). Combination of AMD15057 (1mg/kg iv) with AMD3100 (5mg/kg sc) resulted in synergistic mobilization of CFU-GM (60-fold) when compared to each agent alone (p&lt;0.01). In addition, when AMD3100 and AMD15057 were administered to mice after 5 days of mobilization with G-CSF (17-fold), a dramatic, rapid and reversible mobilization of CFU-GM was observed (200-fold) which was significantly higher than G-CSF+AMD3100 (90-fold) and G-CSF+AMD15057 (90-fold). LTRC assays confirmed that both AMD3100 and AMD15057 induced the rapid mobilization of short and long term repopulating cells and that this effect was synergistic when both agents were co-administered and exceed the LTRC seen after G-CSF mobilization. Secondary transplants confirmed the long term repopulating capacity of HSC mobilized with AMD15057. Conclusions: The VCAM1/VLA-4 axis is involved in HSC trafficking. AMD15057 is effective in blocking the interaction between VLA4 and its ligand fibronectin. AMD15057 induces rapid and reversible mobilization of normal progenitors and HSC which have the long term repopulating capacity. Finally, a dramatic synergistic effect was observed when AMD15057 was combined with AMD3100, G-CSF and the combination. The results provide a plausible foundation for replacing G-CSF with small molecule inhibitors of CXCR4 and VLA-4 for rapid and reversible HSC mobilization in humans.

scholarly journals Small Molecule-Mediated Directed Differentiation of Human Embryonic Stem Cells Toward Ventricular Cardiomyocytes

2013 ◽  
Vol 3 (1) ◽  
pp. 18-31 ◽  
Author(s):  
Ioannis Karakikes ◽  
Grant D. Senyei ◽  
Jens Hansen ◽  
Chi-Wing Kong ◽  
Evren U. Azeloglu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Small Molecule ◽  
Human Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Directed Differentiation ◽  
Ventricular Cardiomyocytes
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