Table 1.
Mean half-maximal inhibitory concentrations for lapatinib inhibition of HER2 and signaling proteins in PIK3CA mutant cells a
| HER2 | Akt | Increase over WT | S6 | Increase over WT | |
|---|---|---|---|---|---|
| BT474 |
0.0411 |
0.0300 |
|
0.0347 |
|
| BT474 LR |
0.0204 |
0.3925 |
13.1 |
0.7863 |
22.7 |
| BT474 wt |
0.0798 |
0.0387 |
|
0.0506 |
|
| BT474 E545K |
0.0852 |
0.1098 |
2.8 |
0.1251 |
2.5 |
| BT474 H1047R |
0.0978 |
0.1336 |
3.4 |
0.1829 |
3.6 |
| SKBR3 |
0.0254 |
0.0077 |
|
0.0106 |
|
| SKBR3 wt |
0.0297 |
0.0293 |
|
0.0593 |
|
| SKBR3 E545K |
0.0211 |
0.0936 |
3.2 |
0.1563 |
2.6 |
| SKBR3 H1047R |
0.0241 |
0.0770 |
2.6 |
0.2028 |
3.4 |
| MDA361 |
0.0160 |
0.0092 |
0.5 |
0.0354 |
1.6 |
| HCC1954 |
0.0681 |
0.2527 |
13.4 |
0.1678 |
7.4 |
| SUM190 |
0.0465 |
0.0464 |
2.5 |
0.1461 |
6.5 |
| UACC893 | 0.0444 | 0.2920 | 15.5 | 4.0040 | 177.0 |
aWT, Wild type. Half-maximal inhibitory concentration (IC50) values for inhibition of HER2, Akt and S6 phosphorylation by lapatinib treatment were determined by enzyme-linked immunosorbent assay (dose–response curves are shown in Additional file 6: Figure S2, Additional file 7: Figure S3 and Additional file 8: Figure S4). Mean IC50 values derived from at least three separate experiments are shown. For phosphoinositide 3-kinase signaling proteins Akt and S6, IC50 values from cells with PIK3CA mutations were compared to average values for cells without hotspot mutations (BT474 and SKBR3).