Erratum

After publication of the original article [1], it is noticed that all the Figures in the HTML version of the article are incorrect, please see the correct figures below. We apologize for any inconvenience caused.

Fig. 1
figure 1

Gene expression of ATP-dependent binding cassette transporters. a Microarray analysis of mammary glands from Apc Min/+ and Apc +/+ mice at d16 of lactation show a decrease in ABCG2 and increase in MDR1 expression due to Apc mutation. b MDR1 gene expression in cells from MMTV-PyMT;Apc Min/+ and MMTV-PyMT;Apc +/+ mice after 24 h treatment with either solvent control, paclitaxel, cisplatin or doxorubicin. MDR1 expression was significantly increased in cells from MMTV-PyMT;Apc Min/+ mice after treatment with paclitaxel and doxorubicin but not cisplatin. c ABCG2 gene expression in cells from MMTV-PyMT;Apc Min/+ and MMTV-PyMT;Apc +/+ mice after treatment for 24 h with either solvent control, paclitaxel, cisplatin or doxorubicin. ABCG2 expression was not different between MMTV-PyMT;Apc Min/+ and MMTV-PyMT;Apc +/+ cells and chemotherapy treatment had no effect on ABCG2 expression. d Representative western blots for MDR1 and ABCG2 in cells from MMTV-PyMT;Apc Min/+ and MMTV-PyMT;Apc +/+ mice after treatment for 24 h with either solvent control, paclitaxel, cisplatin or doxorubicin. e Quantification of MDR1 western blots shows that MMTV-PyMT;Apc Min/+ cells have enhanced MDR1 expression when treated with doxorubicin. f Quantification of ABCG2 western blots shows that MMTV-PyMT;Apc +/+ cells have elevated ABCG2 protein expression compared to MMTV-PyMT;Apc Min/+ cells. Results in b, c, e and f are shown as the means ± SEM from 3 independent experiments; *P < 0.05 when comparing MMTV-PyMT;Apc Min/+ to MMTV-PyMT;Apc +/+ cells and #P < 0.05 when comparing MMTV-PyMT;Apc Min/+ cells treated with solvent control or chemotherapy agent

Fig. 2
figure 2

Cell proliferation and apoptosis in MMTV-PyMT;Apc Min/+ and MMTV-PyMT;Apc +/+ cells after treatment with paclitaxel, cisplatin and doxorubicin. a Cell proliferation as measured by BrdU incorporation after chemotherapuetic treatment. MMTV-PyMT;Apc Min/+ cells showed a modest decrease in proliferation after treatment with cisplatin and doxorubicin compared to MMTV-PyMT;Apc +/+ cells. b Apoptosis as measured by cleaved caspase 3 immunofluorescence (IF). The percentage of apoptosis was lower in cisplatin and doxorubicin treated MMTV-PyMT;Apc Min/+ compared to MMTV-PyMT;Apc +/+ cells while paclitaxel treatment did not affect apoptosis levels. c Representative images of cleaved caspase 3 (CC3) IF. The scale bar is equal to 200 microns. White arrows are representative cleaved caspase 3 positive cells. Data are shown as the means ± SEM from 3 independent experiments; *P < 0.05

Fig. 3
figure 3

Apoptosis in MMTV-PyMT;Apc Min/+ and MMTV-PyMT;Apc +/+ cells treated with chemotherapeutic drugs and targeted inhibitors. a Apoptosis was measured by cleaved caspase 3 IF in the presence of cisplatin. Treatment with cisplatin and either PP2 or SP600125 significantly increases apoptosis compared to cisplatin alone in MMTV-PyMT;Apc Min/+cells. No effect was observed with the addition of PP2 or SP600125 in the MMTV-PyMT;Apc +/+cells. b Apoptosis was measured by cleaved caspase 3 IF with doxorubicin treatments. c Representative cleaved caspase 3 IF images of cells treated with cisplatin and the targeted inhibitor. The scale bar is equal to 200 microns and arrows are used to depict specific cleaved caspase 3 (CC 3) positive cells in each image. Data are shown as the means ± SEM from 3 independent experiments; *P < 0.05 when comparing MMTV-PyMT;Apc Min/+ to MMTV-PyMT;Apc +/+ cells and ** P < 0.05 when comparing the combination treatment versus a single agent (cisplatin or doxorubicin)

Fig. 4
figure 4

MMTV-PyMT;Apc Min/+ cells have higher aldehyde dehydrogenase (ALDH) enzyme activity than MMTV-PyMT;Apc +/+ cells. ALDH activity was measured using an Aldefluor™ Kit. For each cell line a Control (+DEAB) and test (−DEAB) sample were run. a Representative FACS analysis of ALDH activity in MMTVPyMT; Apc +/+ and MMTV-PyMT;Apc Min/+ cells using the Aldefluor™ assay. ALDH activity is increased in MMTV-PyMT;Apc Min/+ cells. b The population of cells that shifted outside of the control population was calculated for each test sample, indicating ALDH activity. MMTV-PyMT;Apc Min/+cells show a larger percentage of cells shifted outside of the control range than MMTV-PyMT;Apc +/+cells. Data are shown as the means ± SEM from 3 independent experiments; *P < 0.05

Fig. 5
figure 5

APC knockdown in MDA-MB-157 cells impacts response to paclitaxel and cisplatin. a Quantitative RT-PCR in MDA-MB-157 cells and shAPC constructs shows decreased level of APC in cells infected with the shAPC constructs. b Representative APC immunofluorescence images showing that APC knockdown cells have less APC protein compared to the MDA-MB-157 parent line. c Cell proliferation as measured by BrdU incorporation did not differ between the three cell lines after treatment with cisplatin, doxorubicin or paclitaxel. d Apoptosis as measured by cleaved caspase 3 IF. The percentage of apoptosis was lower in paclitaxel treated shAPC 1 and cisplatin treated shAPC 2 cells compared to MDA-MB-157 control cells. Doxorubicin treatment had no effect on rates of apoptosis. e Representative images of CC3 IF. Although there are a similar number of positive cells in many of the images, there are fewer total cells in those images representing treatments with a higher percent of apoptosis. The scale bar is equal to 100 microns (e) and 20 microns (b). Data are shown as the means ± SEM from 3 independent experiments; *P < 0.05