Intratumoral heterogeneity in a Trp53-null mouse model of human breast cancer.
Intratumoral heterogeneity correlates with clinical outcome and reflects the cellular complexity and dynamics within a tumor. Such heterogeneity is thought to contribute to radio- and chemoresistance because many treatments may target only certain tumor cell subpopulations. A better understanding of the functional interactions between various subpopulations of cells, therefore, may help in the development of effective cancer treatments. We identified a unique subpopulation of tumor cells expressing mesenchymal-like markers in a Trp53-null mouse model of basal-like breast cancer using fluorescence-activated cell sorting and microarray analysis. Both in vitro and in vivo experiments revealed the existence of cross-talk between these "mesenchymal-like" cells and tumor-initiating cells. Knockdown of genes encoding ligands upregulated in the mesenchymal cells and their corresponding receptors in the tumor-initiating cells resulted in reduced tumorigenicity and increased tumor latency. These studies illustrate the non-cell-autonomous properties and importance of cooperativity between tumor subpopulations.


CONCLUSIONS
Intratumoral heterogeneity has been considered one important factor in assessing a patient's initial response to treatment and selecting drug regimens to effectively increase tumor response rate. Elucidating the functional interactions between various subpopulations of tumor cells will help provide important new insights in understanding treatment response and tumor progression.
Department of Developmental Biology, University of Pittsburgh, Pittsburgh, Pennsylvania. meizhang@pitt.edu jrosen@bcm.edu.
Mei
M
Zhang
Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas.
Anna
A
Tsimelzon
Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas.
Chi-Hsuan
CH
Chang
Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
Cheng
C
Fan
Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA.
Andrew
A
Wolff
Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
Charles M
CM
Perou
Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas.
Susan G
SG
Hilsenbeck
Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas. meizhang@pitt.edu jrosen@bcm.edu.
Jeffrey M
JM
Rosen
D000818:Animals; D000954:Antigens, Surface / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D002453:Cell Cycle / Q000235:genetics; D000066673:Cell Self Renewal; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000378:metabolism; D018920:Coculture Techniques; D004195:Disease Models, Animal; D015536:Down-Regulation; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D016130:Immunophenotyping; D051379:Mice; D018345:Mice, Knockout; D008819:Mice, Nude; D014411:Neoplastic Stem Cells / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency / Q000235:genetics*
D000954:Antigens, Surface; D014408:Biomarkers, Tumor; D016159:Tumor Suppressor Protein p53