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| Status |
Public on Aug 27, 2009 |
| Title |
Antiestrogen-resistant subclones of MCF-7 human breast cancer cells are derived from a common clonal drug-resistant progenitor |
| Organism |
Homo sapiens |
| Experiment type |
Expression profiling by array
|
| Summary |
Emergence of antiestrogen-resistant cells in MCF-7 cells during suppression of estrogen signaling is a widely accepted model of acquired breast cancer resistance to endocrine therapy. To obtain insight into the genomic basis of endocrine therapy resistance, we characterized MCF-7 monoclonal sublines that survived 21-day exposure to tamoxifen (T-series sublines) or fulvestrant (F-series sublines) and sublines unselected by drugs (U-series). All T/F-sublines were resistant to the cytocidal effects of both tamoxifen and fulvestrant. However, their responses to the cytostatic effects of fulvestrant varied greatly, and their remarkably diversified morphology showed no correlation with drug resistance. mRNA expression profiles of the U-sublines differed significantly from those of the T/F-sublines, whose transcriptomal responsiveness to fulvestrant was largely lost. A set of genes strongly expressed in the U-sublines successfully predicted metastasis-free survival of breast cancer patients. Most T/F-sublines shared highly homogeneous genomic DNA aberration patterns that were distinct from those of the U-sublines. Genomic DNA of the U-sublines harbored many aberrations that were not found in the T/F-sublines. These results suggest that the T/F-sublines are derived from a common monoclonal progenitor that lost transcriptomal responsiveness to antiestrogens as a consequence of genetic abnormalities many population doublings ago, not from the antiestrogen-sensitive cells in the same culture during the exposure to antiestrogens. Thus, the apparent acquisition of antiestrogen resistance by MCF-7 cells reflects selection of preexisting drug-resistant subpopulations without involving changes in individual cells. Our results suggest the importance of clonal selection in endocrine therapy resistance of breast cancer.
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| Overall design |
We picked well-isolated colonies from polyclonal MCF-7 cell culture to
establish sublines. All sublines characterized were confirmed as
monoclonal by their homogeneous morphology. The unselected
anti-estrogen-sensitive U-series sublines were derived from colonies
that emerged in low-density MCF-7 cultures without drug pressure. The
anti-estrogen-resistant sublines were isolated by exposing
high-density MCF-7 cultures to fulvestrant (Fv, 10–100 nM) or
4-hydroxytamoxifen (Tam, 1M) for 21 days. Approximately 1 in 10^5 to
2 X 10^6 anti-estrogen-exposed cells survived this drug pressure. After
a 7-day drug-free recovery period, colonies were picked to establish
the Tam-selected T-series and the Fv-selected F-series sublines. All
T/F-sublines were maintained in the absence of anti-estrogens and were
characterized within 20 population doublings.
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| Contributor(s) |
Coser KR, Rosenthal NF, Wittner BS, Ramaswamy S, Shioda T |
| Citation(s) |
19706540, 26479444 |
| |
| Submission date |
Feb 25, 2009 |
| Last update date |
Mar 30, 2020 |
| Contact name |
Ben S. Wittner |
| E-mail(s) |
[email protected]
|
| Organization name |
Massachusetts General Hospital
|
| Department |
Center for Cancer Research
|
| Lab |
Lawrence
|
| Street address |
149 13th Street
|
| City |
Boston |
| State/province |
MA |
| ZIP/Postal code |
02129 |
| Country |
USA |
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| Platforms (1) |
| GPL570 |
[HG-U133_Plus_2] Affymetrix Human Genome U133 Plus 2.0 Array |
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| Samples (30)
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| Relations |
| BioProject |
PRJNA111897 |
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