Abstract 4573

Human mesenchymal stem cells (MSCs) derived from bone marrows are characterized by high proliferative potential and pluripotentiality to differentiate into multiple lineages such as osteo-, chondro-, and adipogenic cells. MSC express CD105, CD73 and CD90, but not CD45, CD34, CD14 or CD11b, CD79alpha or CD19 and HLA-DR surface molecules. In this study, we observed that MSC derived from the bone marrow of four AML patients differentiated into B-cell lymphoblasts with NOD/SCID/IL-2Rg-/- engraftment potential.

MSC cell lines were established by culturing adherent cells from newly diagnosed AML (n=4) age 20 to 74 years in alpha-DMEM medium supplement with 20% fetal bovine serum. Surface antigen phenotype analysis and G-banding karyotype analysis were performed in passage 2 to 4. FACS-sorted CD90 positive cells were then intravenously (I.V.) injected into NOD/SCID/IL-2Rg-/- (NOG) mice via tail vein (n=9) or into the bone marrow (n=3). Circulating cells were analyzed for CD19, CD33, CD34, and CD90 expression on day 36, 45, 60, 75 after injection of MSC.

Results

1) G-banding showed normal karyotype in all MSC; 2) Injected MSC engrafted and differentiated in NOG mice. Surprisingly, CD19 positive cells were found in all samples starting on day 36 (table) and increased on day 60 and 75 (from d36: 6.9±3.5%, d45:0.7±0.1%, d60:2.6 ± 1.6% and d75: 9.3 ± 1.0%); 3) CD90 positive cells were found on day 45 (range from 0.07-3.96% and decreased to 0.1-0.5% on day 75). Low percentage of CD33 (day 45: 0.19-0.78% and day 60: 0.12-2.53%) and CD34 positive cells (day 45: 0.32-1.9% and day 60: 0.21-2.39%) were observed before day 60 and were undetectable by day 75.

CaseSpecimenInjectedMicePercentage of CD19 Positive Cells
Day-36Day-45Day-60Day-75
1 AML IV Mouse-1* 5.83    
   Mouse-2* 1.45    
   Mouse-3 13.5  16.5  
2 AML IV Mouse-1  0.28 1.84 6.9 
   Mouse-2  0.37 0.29 7.5 
3 AML IV Mouse-1  0.67 1.83 5.2 
   Mouse-2  0.89 0.52 10.9 
4 AML IV Mouse-1  0.93 0.15 13.4 
   Mouse-2  0.61 0.18 9.9 
  BM Mouse-1  0.8 1.22 6.2 
   Mouse-2  0.54 1.91 11.8 
   Mouse-3  0.82 1.31 11.7 
Mean ±SEM    6.93±3.52 0.66±0.08 2.58±1.56 9.28±0.96 
CaseSpecimenInjectedMicePercentage of CD19 Positive Cells
Day-36Day-45Day-60Day-75
1 AML IV Mouse-1* 5.83    
   Mouse-2* 1.45    
   Mouse-3 13.5  16.5  
2 AML IV Mouse-1  0.28 1.84 6.9 
   Mouse-2  0.37 0.29 7.5 
3 AML IV Mouse-1  0.67 1.83 5.2 
   Mouse-2  0.89 0.52 10.9 
4 AML IV Mouse-1  0.93 0.15 13.4 
   Mouse-2  0.61 0.18 9.9 
  BM Mouse-1  0.8 1.22 6.2 
   Mouse-2  0.54 1.91 11.8 
   Mouse-3  0.82 1.31 11.7 
Mean ±SEM    6.93±3.52 0.66±0.08 2.58±1.56 9.28±0.96 
View Large

Table shows the percentages of CD19+ cells found in circulation in NOD/SCID/IL-2Rg-/- (NOG) mice after MSC I.V. or intra-bone marrow injection. (* Mice died after phlebotomy.)

Conclusion

Human MSC derived from AML bone marrows have the capacity to differentiate into CD19 positive B lymphocyte in NOG mice in vivo. It has previously been reported that AML can be propagated by a leukemic stem cell with lymphoid characteristics (Cancer Cell 2006, 10, 363-74). Data reported here suggest the possibility that AML-derived MSC give rise to lymphoid cells that engraft in NOG mice. This unexpected finding could shed light on the role of stroma cells in the pathogenesis and propagation of leukemias.

Disclosures:

No relevant conflicts of interest to declare.

Topics:
b-lymphocytes, leukemia, myelocytic, acute, mice, severe combined immunodeficiency, stem cell, mesenchymal, cd19 antigens, cd34 antigens, cd33 antigen, g-banding, karyotype determination procedure

Author notes

*

Asterisk with author names denotes non-ASH members.

© 2009 by The American Society of Hematology
2009
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