Table 3.
Effect of anti-HERV-K antibody treatment on protein expression in breast cell lines, analyzed by flow cytometry*
| Fold change in expression relative to HEK293 |
Fold change in expression relative to MCF-10AT |
|||||||
| Protein | Cell line | Mean fold change | Difference | 95% CI | P† | Difference | 95% CI | P† |
| CIDEA | HEK293T | 1.04 | — | — | — | — | — | — |
| MCF-10AT | 2.44 | 1.40 | 1.05 to 1.77 | <.001 | — | — | — | |
| MCF-7 | 6.86 | 5.82 | 5.51 to 6.14 | <.001 | 4.42 | 4.24 to 4.60 | <.001 | |
| MDA-MB-231 | 15.12 | 14.08 | 12.78 to 15.38 | <.001 | 12.67 | 11.40 to 13.94 | <.001 | |
| SKBR3 | 15.95 | 14.91 | 14.60 to 15.23 | <.001 | 13.5 | 13.32 to 13.68 | <.001 | |
| T47D | 8.14 | 7.10 | 6.79 to 7.42 | <.001 | 5.69 | 5.51 to 5.87 | <.001 | |
| Caspase 3 | HEK293T | 1.03 | — | — | — | — | — | — |
| MCF-10AT | 1.83 | 0.800 | 1.62 to 4.58 | .004 | — | — | — | |
| MCF-7 | 3.51 | 2.47 | 1.53 to 3.42 | .013 | 1.67 | 0.99 to 2.36 | .043 | |
| MDA-MB-231 | 16.75 | 15.71 | 12.65 to 18.78 | .001 | 14.91 | 11.92 to 17.91 | <.001 | |
| SKBR3 | 3.65 | 1.82 | 1.51 to 2.12 | <.001 | 2.62 | 1.89 to 3.34 | <.001 | |
| T47D | 4.71 | 3.68 | 2.96 to 4.40 | <.001 | 2.88 | 2.58 to 3.17 | <.001 | |
| Caspase 7 | HEK293T | 1.63 | — | — | — | — | — | — |
| MCF-10AT | 4.06 | 2.43 | 2.13 to 2.74 | <.001 | — | — | — | |
| MCF-7 | 4.87 | 3.24 | 2.94 to 3.54 | <.001 | .800 | 0.71 to 0.90 | <.001 | |
| MDA-MB-231 | 32.32 | — | — | — | — | — | — | |
| SKBR3 | 18.68 | 17.05 | 16.76 to 17.35 | <.001 | 14.62 | 14.54 to 14.70 | <.001 | |
| T47D | 13.67 | 12.04 | 11.75 to 12.34 | <.001 | 9.61 | 9.53 to 9.69 | <.001 | |
| Caspase 8 | HEK293T | 1.01 | — | — | — | — | — | — |
| MCF-10AT | 2.47 | 1.46 | 1.20 to 1.73 | <.001 | — | — | — | |
| MCF-7 | 7.63 | 6.62 | 6.36 to 6.88 | <.001 | 5.16 | 5.06 to 5.26 | <.001 | |
| MDA-MB-231 | 14.05 | 13.04 | 5.96 to 20.12 | .007 | 11.58 | 4.51 to 18.65 | .011 | |
| SKBR3 | 23.7 | 22.7 | 22.44 to 22.95 | <.001 | 21.23 | 21.15 to 21.32 | <.001 | |
| T47D | 6.49 | 5.49 | 5.23 to 5.74 | <.001 | 4.02 | 3.94 to 4.11 | <.001 | |
| Caspase 9 | HEK293T | 1.04 | — | — | — | — | — | — |
| MCF-10AT | 3.69 | 2.65 | 2.52 to 2.79 | <.001 | — | — | — | |
| MCF-7 | 4.34 | 3.3 | 3.13 to 3.46 2 | <.001 | .64 | 0.52 to 0.66 | <.001 | |
| MDA-MB-231 | 24.28 | 23.24 | 10.31 to 36.18 | .008 | 2.59 | 7.65 to 33.52 | .012 | |
| SKBR3 | 13.99 | 12.95 | 12.83 to 13.08 | <.001 | 10.3 | 10.24 to 10.36 | <.001 | |
| T47D | 5.83 | 4.79 | 4.65 to 4.92 | <.001 | 2.13 | 2.06 to 2.21 | <.001 | |
| TP53 | HEK293T | 1.24 | — | — | — | — | — | — |
| MCF-10AT | 1.93 | .698 | 0.376 to 1.02 | .004 | — | — | — | |
| MCF-7 | 4.24 | 3.01 | 2.67 to 3.34 | <.001 | 2.31 | 2.21 to 2.40 | <.001 | |
| MDA-MB-231 | 22.59 | — | — | — | — | — | — | |
| SKBR3 | 18.94 | 17.71 | 17.39 to 18.03 | <.001 | 17.01 | 16.99 to 17.03 | <.001 | |
| T47D | 6.19 | 4.95 | 4.63 to 5.27 | <.001 | 4.25 | 4.22 to 4.28 | <.001 | |
| FASLG | HEK293T | 1.15 | — | — | — | — | — | — |
| MCF-10AT | 7.03 | 5.88 | — | <.001 | — | — | — | |
| MCF-7 | 6.06 | 4.91 | 2.62 to 7.19 | .004 | .973 | −3.37 to 1.42 | .32 | |
| MDA-MB-231 | — | — | — | — | — | — | — | |
| SKBR3 | 20.84 | 19.69 | 13.83 to 25.56 | <.001 | 15.57 | 7.91 to 19.72 | .003 | |
| T47D | 10.33 | 9.18 | 5.57 to 12.80 | .002 | 3.22 | 0.386 to 6.99 | .068 | |
| CDKN1A | HEK293T | 1.13 | — | — | — | — | — | — |
| MCF-10AT | 3.37 | 2.24 | 2.00 to 2.47 | <.001 | — | — | — | |
| MCF-7 | 5.75 | 4.62 | 4.382 to 4.85 | <.001 | 2.38 | 2.32 to 2.44 | <.001 | |
| MDA-MB-231 | 33.11 | 21.97 | 28.00 to 35.94 | <.001 | 25.77 to 33.70 | <.001 | ||
| SKBR3 | 18.95 | 17.81 | 17.58 to 18.04 | <.001 | 15.57 | 15.53 to 15.62 | <.001 | |
| T47D | 6.59 | 5.46 | 5.22 to 5.69 | <.001 | 3.22 | 3.16 to 3.28 | <.001 | |
| CDK5 | HEK293T | 1.6 | — | — | — | — | — | — |
| MCF-10AT | 2.56 | .959 | 0.329 to 1.59 | .013 | — | — | — | |
| MCF-7 | 1.95 | .35 | 0.170 to 0.870 | .135 | −.609 | −1.26 to 0.039 | .060 | |
| MDA-MB-231 | 14.99 | 13.38 | 12.64 to 14.12 | <.001 | 12.42 | 11.58 to 13.26 | <.001 | |
| SKBR3 | 7.45 | 5.84 | 5.34 to 6.34 | <.001 | 4.88 | 4.25 to 5.52 | <.001 | |
| T47D | 7.56 | 5.95 | 4.51 to 16.42 | .226 | 5 | −5.47 to 15.46 | .30 | |
HEK293Tcells, the nonmalignant breast cell line MCF-10AT, and the breast cancer cell lines MCF-7, MDA-MB-231, SKBR3, and T47D, were treated with 6H5 mAb or mIgG (10 μg/mL per dose of each antibody) for 24 hours and analyzed for protein expression by flow cytometry. The fold changes in protein levels of CIDEA, caspase 3, 7, 8, and 9, TP53, CDKN1A, and CDK5of 6H5 mAb–treated or mIgG-treated cells were compared. The fold changes in mAb-treated breast cancer cells were compared with fold changes in mAb-treated HEK293T or MCF-10AT cells. The mean values from at least three independent experiments are presented. CI = confidence interval; CIDEA = cell death–inducing DFFA-like effector A; mAb = monoclonal antibody; — = not applicable.
P values reflect comparisons between HEK293T cells and each breast cancer cell line, or between MCF-10AT cells and each breast cancer cell line, and were calculated using a two-sided Student‘s t test.