Paracrine Pathways in Uterine Leiomyoma Stem Cells Involve Insulinlike Growth Factor 2 and Insulin Receptor A.
Uterine leiomyomas (fibroids) are the most common benign tumors in women. Recently, three populations of leiomyoma cells were discovered on the basis of CD34 and CD49b expression, but molecular differences between these populations remain unknown.



To define differential gene expression and signaling pathways in leiomyoma cell populations.



Cells from human leiomyoma tissue were sorted by flow cytometry into three populations: CD34+/CD49b+, CD34+/CD49b-, and CD34-/CD49b-. Microarray gene expression profiling and pathway analysis were performed. To investigate the insulinlike growth factor (IGF) pathway, real-time quantitative polymerase chain reaction, immunoblotting, and 5-ethynyl-2'-deoxyuridine incorporation studies were performed in cells isolated from fresh leiomyoma.



Research laboratory.



Eight African American women.



None.



Gene expression patterns, cell proliferation, and differentiation.



A total of 1164 genes were differentially expressed in the three leiomyoma cell populations, suggesting a hierarchical differentiation order whereby CD34+/CD49b+ stem cells differentiate to CD34+/CD49b- intermediary cells, which then terminally differentiate to CD34-/CD49b- cells. Pathway analysis revealed differential expression of several IGF signaling pathway genes. IGF2 was overexpressed in CD34+/CD49b- vs CD34-/CD49b- cells (83-fold; P < 0.05). Insulin receptor A (IR-A) expression was higher and IGF1 receptor lower in CD34+/CD49b+ vs CD34-/CD49b- cells (15-fold and 0.35-fold, respectively; P < 0.05). IGF2 significantly increased cell number (1.4-fold; P < 0.001), proliferation indices, and extracellular signal-regulated kinase (ERK) phosphorylation. ERK inhibition decreased IGF2-stimulated cell proliferation.



IGF2 and IR-A are important for leiomyoma stem cell proliferation and may represent paracrine signaling between leiomyoma cell types. Therapies targeting the IGF pathway should be investigated for both treatment and prevention of leiomyomas.
Division of Reproductive Science in Medicine, Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611.
Molly B
MB
Moravek
Division of Reproductive Science in Medicine, Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611.
Ping
P
Yin
Division of Reproductive Science in Medicine, Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611.
John S
JS
Coon
Division of Reproductive Science in Medicine, Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611.
Masanori
M
Ono
Division of Reproductive Science in Medicine, Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611.
Stacy A
SA
Druschitz
Division of Reproductive Science in Medicine, Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611.
Saurabh S
SS
Malpani
Division of Reproductive Science in Medicine, Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611.
Matthew T
MT
Dyson
Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611.
Alfred W
AW
Rademaker
Division of Reproductive Science in Medicine, Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611.
Jared C
JC
Robins
Division of Reproductive Science in Medicine, Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611.|Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611.
Jian-Jun
JJ
Wei
Division of Reproductive Science in Medicine, Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611.
J Julie
JJ
Kim
Division of Reproductive Science in Medicine, Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611.
Serdar E
SE
Bulun
D000328:Adult; D001741:Black or African American; D015703:Antigens, CD / Q000235:genetics* / Q000378:metabolism; D018952:Antigens, CD34 / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics*; D049109:Cell Proliferation / Q000235:genetics*; D005260:Female; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D006801:Humans; D015151:Immunoblotting; D007335:Insulin-Like Growth Factor II / Q000235:genetics* / Q000378:metabolism; D039421:Integrin alpha2 / Q000378:metabolism; D007889:Leiomyoma / Q000235:genetics* / Q000378:metabolism; D020935:MAP Kinase Signaling System; D008875:Middle Aged; D014411:Neoplastic Stem Cells / Q000166:cytology* / Q000378:metabolism; D019899:Paracrine Communication / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D011972:Receptor, Insulin / Q000235:genetics* / Q000378:metabolism; D046888:Tissue Array Analysis; D014594:Uterine Neoplasms / Q000235:genetics* / Q000378:metabolism
D015703:Antigens, CD; D018952:Antigens, CD34; C035170:IGF2 protein, human; D039421:Integrin alpha2; D007335:Insulin-Like Growth Factor II; C435941:INSR protein, human; D011972:Receptor, Insulin