Residual breast cancers after conventional therapy display mesenchymal as well as tumor-initiating features.
Some breast cancers have been shown to contain a small fraction of cells characterized by CD44(+)/CD24(-/low) cell-surface antigen profile that have high tumor-initiating potential. In addition, breast cancer cells propagated in vitro as mammospheres (MSs) have also been shown to be enriched for cells capable of self-renewal. In this study, we have defined a gene expression signature common to both CD44(+)/CD24(-/low) and MS-forming cells. To examine its clinical significance, we determined whether tumor cells surviving after conventional treatments were enriched for cells bearing this CD44(+)/CD24(-/low)-MS signature. The CD44(+)/CD24(-/low)-MS signature was found mainly in human breast tumors of the recently identified "claudin-low" molecular subtype, which is characterized by expression of many epithelial-mesenchymal-transition (EMT)-associated genes. Both CD44(+)/CD24(-/low)-MS and claudin-low signatures were more pronounced in tumor tissue remaining after either endocrine therapy (letrozole) or chemotherapy (docetaxel), consistent with the selective survival of tumor-initiating cells posttreatment. We confirmed an increased expression of mesenchymal markers, including vimentin (VIM) in cytokeratin-positive epithelial cells metalloproteinase 2 (MMP2), in two separate sets of postletrozole vs. pretreatment specimens. Taken together, these data provide supporting evidence that the residual breast tumor cell populations surviving after conventional treatment may be enriched for subpopulations of cells with both tumor-initiating and mesenchymal features. Targeting proteins involved in EMT may provide a therapeutic strategy for eliminating surviving cells to prevent recurrence and improve long-term survival in breast cancer patients.
Creighton
Chad J
CJ
Department of Molecular and Cellular Biology, Division of Biostatistics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA.
Li
Xiaoxian
X
Landis
Melissa
M
Dixon
J Michael
JM
Neumeister
Veronique M
VM
Sjolund
Ashley
A
Rimm
David L
DL
Wong
Helen
H
Rodriguez
Angel
A
Herschkowitz
Jason I
JI
Fan
Cheng
C
Zhang
Xiaomei
X
He
Xiaping
X
Pavlick
Anne
A
Gutierrez
M Carolina
MC
Renshaw
Lorna
L
Larionov
Alexey A
AA
Faratian
Dana
D
Hilsenbeck
Susan G
SG
Perou
Charles M
CM
Lewis
Michael T
MT
Rosen
Jeffrey M
JM
Chang
Jenny C
JC
D001706:Biopsy; D001943:Breast Neoplasms / Q000378:metabolism* / Q000628:therapy*; D051927:CD24 Antigen / Q000096:biosynthesis; D002462:Cell Membrane / Q000378:metabolism; D062445:Claudin-1; D004848:Epithelium / Q000473:pathology; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D018960:Hyaluronan Receptors / Q000096:biosynthesis; D008565:Membrane Proteins / Q000096:biosynthesis; D008648:Mesoderm / Q000378:metabolism*; D008954:Models, Biological; D018365:Neoplasm, Residual / Q000209:etiology*; D016133:Polymerase Chain Reaction; D016896:Treatment Outcome
D051927:CD24 Antigen; C568108:CLDN1 protein, human; D062445:Claudin-1; D018960:Hyaluronan Receptors; D008565:Membrane Proteins