Background
Methods
Chemicals and drugs
Cell cultures
Establishment of SN-38 resistant human breast cancer cell lines
Cell Lines | SN-38 Dose | Final SN-38 concentration | IC50 Values (μM) | RR | |
---|---|---|---|---|---|
Resistant cell lines | DMSO control | ||||
MDAacq
| Stepwise (3.6nM-68.2nM) | 68.2nM | 40.2 ± 4.0 | 5.6 ± 0.9 | 7.2 |
MCF-7acq
| Stepwise (3.0nM-36nM) | 36nM | 33.6 ± 3.0 | 3.7 ± 0.5 | 9.1 |
MDAde novo
| Constant (24nM) | 24nM | 66.8 ± 16.2 | 0.7 ± 0.5 | 95.4 |
MCF-7de novo
| Constant (12nM) | 12nM | 31.9 ± 0.6 | 2.3 ± 0.9 | 13.9 |
Data mining of publicly available datasets
Cytotoxicity assay
Cell growth and doubling time analysis
Cell cycle analysis by FACS
Formalin fixation and paraffin embedding of cells
FISH analysis
Copy number data and mRNA microarray analysis on the 52 breast cancer cell lines
mRNA microarray analysis on parental and the acquired resistant cell lines
Availability of data and materials
Protein purification, western blotting and Peggy analyses
Top1 enzyme activity assay
BCRP drug-efflux pump inhibition
Statistics
Results
Topoisomerase 1 as predictor of response to SN-38
Establishment and characterization of resistant cell lines
Growth curves
Cell-cycle distribution
Cross-resistance to other anti-cancer drugs
Anti- cancer drugs | Epirubicin | RR | Docetaxel | RR | Cisplatin | RR | LMP776 | RR | LMP400 | RR |
---|---|---|---|---|---|---|---|---|---|---|
MDAacq DMSO | 0.4 ± 0.2 | 4.3 | 22.0 ± 9.9 | 1.0 | 62.8 ± 13.7 | 1.1 | 8.9 ± 11.7 | 5.0 | 10.5 ± 9.7 | 1.2 |
MDAacq
| 1.7 ± 0.3 | 21.0 ± 5.3 | 70.6 ± 4.1 | 44.6 ± 45.7 | 12.4 ± 12.2 | |||||
MCF-7acq DMSO | 0.9 ± 0.5 | 1.9 | 20.4 ± 2.3 | 1.3 | 26.1 ± 9.5 | 2.5 |
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MCF-7acq
| 1.7 ± 0.9 | 25.8 ± 8.2 | 65.6 ± 53.4 |
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MDAde novo DMSO | 5.2 ± 3.2 | 3.4 | 18.0 ± 3.7 | 1.5 | 34.7 ± 7.03 | 2.7 | 11.0 ± 6.2 | 2.0 | 15.8 ± 6.3 | 1.6 |
MDAde novo
| 17.6 ± 1.4 | 27.3 ± 2.1 | 95.1 ± 4.9 | 22.5 ± 4.3 | 25.8 ± 3.5 | |||||
MCF-7de novo DMSO | 8.1 ± 9.1 | 1.2 | 24 ± 7.5 | 1.5 | 45.6 ± 5.4 | 1.2 | 40.0 ± 14.2 | 1.4 | 42.6 ± 36.3 | 1.4 |
MCF-7de novo
| 10.0 ± 7.9 | 34.9 ± 10.2 | 53.7 ± 13.0 | 55.9 ± 28.6 | 58.2 ± 36.5 |