Identification and characterization of the human leiomyoma side population as putative tumor-initiating cells.
OBJECTIVE
To isolate and characterize human leiomyoma stem cells by the side population (SP) method.


METHODS
Prospective experimental human and animal study.


METHODS
University research laboratory-affiliated infertility clinic.


METHODS
Women undergoing laparoscopic myomectomy.


METHODS
Female non-obese diabetic severe combined immune deficiency (NOD-SCID) mutation mice.


METHODS
Obtainment of human leiomyoma SP cells as candidate tumor-initiating cells and establishment of two leiomyoma SP lines.


METHODS
Flow cytometry, semiquantitative polymerase chain reaction, clonogenicity assays, cDNA microarrays hybridization, cell culture, karyotype, molecular analysis, immunocytochemistry, in vitro differentiation, xenotransplantation assays, immunohistochemistry.


RESULTS
SP cells from human leiomyomas were isolated, identified, and characterized. Two leiomyoma's SP cell lines with a normal karyotype were thus established. Undifferentiated status was confirmed by the expression of OCT-4, NANOG, DNMT3B, GDF3. Presence of typical mesenchymal markers (CD90, CD105, CD73) and absence of hematopoietic stem cell markers (CD34, CD45) supported their mesodermal origin. Mesenchymal lineage commitment was also demonstrated by their ability to differentiate in vitro into adipogenic and osteogenic lineages. Finally, their functional capability was established in an animal model by leiomyoma tissue reconstruction.


CONCLUSIONS
SP cells from human leiomyoma exhibit key features of tumor-initiating cells, opening up new possibilities of understanding the origin and developing new nonsurgical approaches for leiomyomas.
Fundación Instituto Valenciano de Infertilidad, Instituto Universitario Instituto Valenciano de Infertilidad, University of Valencia, INCLIVA, Valencia, Spain.
Aymara
A
Mas
Irene
I
Cervelló
Claudia
C
Gil-Sanchis
Amparo
A
Faus
Jaime
J
Ferro
Antonio
A
Pellicer
Carlos
C
Simón
D000818:Animals; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D007889:Leiomyoma / Q000473:pathology*; D051379:Mice; D014411:Neoplastic Stem Cells / Q000473:pathology*; D011446:Prospective Studies; D058985:Side-Population Cells / Q000473:pathology*; D014594:Uterine Neoplasms / Q000473:pathology*