Table 3 In vitro killing of ADCs.

From: Antibody and antibody fragments site-specific conjugation using new Q-tag substrate of bacterial transglutaminase

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

  1. 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.
  2. ND non-determined.
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