Table 3.
In vitro killing of ADCs.
| Cell lines/IC50 (nM) | T-DM1 | Trastuzumab Qtag2 -DM1 | VHH Qtag2-DM1 | scfv-Qtag2-DM1 | DM1 |
|---|---|---|---|---|---|
| SKBR3 (HER2/neu+) | 0.088 ± 0.01 | 0.363 ± 0.02 | 4.364 ± 0.07 | 1.21 ± 0.04 | 3.039 ± 0.07 |
| BT-474 (HER2/neu+) | ∼0.02 ± 2.1 | >10 | 10.1 ± 0.33 | >10 | 112.9 ± 5.8 |
| MDA-MB-231 (HER2/neu-) | >10 | >10 | 3.2 ± 0.56 | >1000 | 2.78 ± 1.75 |
| Cell lines/IC50 (nM) | Trastuzumab Qtag2 -MMAE | MMAE |
|---|---|---|
| SKBR3 (HER2/neu+) | 0.163 ± 0.07 | 3.95 ± 0.66 |
| BT-474 (HER2/neu+) | ∼0.65 ± 10.21 | 147.9 ± 6.25 |
| MDA-MB-231 (HER2/neu-) | >10 | 20.69 ± 7.75 |
A cytotoxicity assay was performed to evaluate inhibitory effect of free and conjugated drugs on cell proliferation. Two types of HER2/neu positive (SKBR3 and BT-474) and MDA-MB-231 a target negative cell line were used in the experiment. Three days after the addition of the drugs, cell death was quantified by sulforhodamine B assay. IC50 values were determined by fitting of non-linear regression curves to the data using GraphPad Prism 7.0b (GraphPad Software Inc., San Diego, CA, USA) software. Data points represent the mean of two independent experiments. T-DM1, Ado-Trastuzumab emtansine (Roche); Trastuzumab-Qtag2-PEG4-SMCC-PAB-DM1; Trastuzumab-Qtag2-PEG4-VC-PAB-MMAE.
ND non-determined.