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. Author manuscript; available in PMC: 2011 Jan 1.
Published in final edited form as: Adv Enzyme Regul. 2009 Nov 4;50(1):285–307. doi: 10.1016/j.advenzreg.2009.10.016

Table 1. IC50s of Drug Sensitive and Resistant Breast Cells [nM]1.

Drug [IC50] MCF-7/
DoxS		 MCF-7/
DoxR		 T47D/
DoxS		 T47D/
DoxR		 MDA-
MB-
231/DoxS		 MDA-
MB-
231/DoxR
Doxorubicin 10 nM 300 nM 20 nM 300 nM 260 nM 800 nM
Fold Increase - 30X↑ - 15X↑ - 3X↑
Etoposide 700 nM 5000 nM 10,000 >50,000 15,000 >50,000
Fold Increase - 7X↑ >5X↑ >3X↑
Paclitaxel 7 nM 200 nM 6 nM 300 nM 5 nM >300 nM
Fold Increase 29X↑ 50X↑ >60X↑
1

MTT analysis was performed with 3 different chemotherapeutic drugs on 3 different drug sensitive and resistant cell lines. Determined by plating 5,000 cells/well in 96 well plates in phenol red free RPMI 1640 + 10% FBS. Serial 2-fold dilutions (n=12 dilutions) at 8 wells per each drug concentration were added after 1 day. MTT analysis was performed after 4 additional days of incubation and results were normalized to untreated cells.