TABLE 2.
IC50 values (µM; four-parameter logistic regression, 95% bootstrap CI in parentheses) from CellTiter-Glo 3D data. Three notations are used. “>50” and “>20” indicate that the fitted curve declined but did not reach 50% inhibition within the tested range; the upper limit of that range was 50 µM (24 h, all lines; 48 and 72 h, SKBR3, HB2 and AC16) or 20 µM (48 and 72 h, MDA-MB-231). “<0.5” indicates that the crossing lies below the lowest tested dose (0.5 µM) and is extrapolated. “n.i.” indicates no inhibition: apparent viability remained close to or above the untreated control at every concentration tested, so no IC50 exists (see Supplementary Table S1). MDA-MB-231 values were recomputed from the raw plate readings with each plate normalized to its own control wells (Section 2.4).
| Cell line | Time | DOX | DOX-ACA-HEX-G8 | DOX-ACA-DBCO-G8 |
|---|---|---|---|---|
| MDA-MB-231 (TNBC) | 24 h | >50 | 15.2 (14.1–16.7) | >50 |
| | 48 h | 1.06 (0.95–1.21) | n.i. | >20 |
| | 72 h | 0.94 (0.90–0.97) | n.i. | 12.6 (8.3–15.5) |
| SKBR3 (HER2+) | 24 h | 1.07 (0.95–1.24) | 13.0 (11.4–14.9) | >50 |
| | 48 h | <0.5 | <0.5 | 19.7 (11.2–44.9) |
| | 72 h | <0.5 | <0.5 | 11.0 (8.59–14.0) |
| HB2 (normal breast) | 24 h | >50 | 29.2 (23.9–36.9) | >50 |
| | 48 h | 1.84 (1.54–1.96) | 24.9 (21.3–27.9) | >50 |
| | 72 h | 0.78 (0.67–0.88) | 11.7 (8.68–13.8) | 29.5 (26.7–31.6) |
| AC16 (cardiomyocyte) | 24 h | 6.00 (4.53–7.12) | 17.6 (15.5–19.5) | 26.5 (24.8–30.8) |
| | 48 h | 2.07 (1.82–2.34) | 9.64 (6.65–12.0) | 23.4 (21.8–24.5) |
| | 72 h | <0.5 | 8.92 (7.84–9.85) | 19.7 (18.0–21.9) |
DOX-ACA-HEX-G8 = DOX-ACA-HEX-O2Oc-[Dap(GO2)]8-O2Oc-NH2; DOX-ACA-DBCO-G8 = DOX-ACA-DBCO-O2Oc-[Dap(GO2)]8-O2Oc-NH2. Values are from three independent biological experiments per cell line and time point, with four to eight technical replicates per concentration per plate. Bootstrap confidence intervals were obtained by resampling replicate wells and therefore describe within-experiment (technical) dispersion. An interval derived instead from the between-experiment spread of three IC50 values would itself rest on three points and be correspondingly unstable; the technical interval is therefore reported as a lower bound on the precision of each estimate and does not quantify between-experiment variability. Supplementary Tables S1–S4 report the mean and SD across the replicate wells of the three experiments at each concentration; per-experiment dose–response values are not tabulated separately.