CI values and DRI for the combination of DCLK knockdown (siDCLK) with VCR or VBL on the reduction of cell proliferation and survival in two neuroblastoma cell lines (N1E-115 and SH-SY5Y)
The CI is based on the formula: CI = (D)1/(Dx)1 + (D)2/(Dx)2 + (D)1(D)2/(Dx)1(Dx)2 (Chou and Talalay, 1984). CI can be <1, 1, and >1, indicating synergism, additive effect and antagonism, respectively. DRI corresponds to how much the dose of each compound in a synergetic combination can be reduced at a certain effect compared with the doses of each compound alone (Chou and Talalay, 1984).
| Cell Line | Combination | Ratio | CI | DRI | |
|---|---|---|---|---|---|
| VCR or VBL | siDCLK | ||||
| nM/μM | |||||
| N1E-115 | siDCL-3/VCR | 12.5:0.01 | 0.424 (synergism) | 3.349 | 7.965 |
| 25:0.1 | 0.343 (synergism) | 4.623 | 7.875 | ||
| 50:1 | 0.469 (synergism) | 3.170 | 6.493 | ||
| 100:10 | 0.815 (moderate synergism) | 1.630 | 4.967 | ||
| siDCL-3/VBL | 12.5:0.01 | 0.153 (strong synergism) | 146.418 | 6.858 | |
| 25:0.1 | 0.263 (strong synergism) | 37.975 | 4.223 | ||
| 50:1 | 0.517 (synergism) | 8.407 | 2.512 | ||
| 100:10 | 0.730 (moderate synergism) | 5.139 | 1.866 | ||
| SH-SY5Y | siDCLK-4/VCR | 50:0.1 | 0.066 (very strong synergism) | 2.631E + 3 | 15.151 |
| 100:1 | 0.199 (strong synergism) | 22.630 | 6.442 | ||
| 200:10 | 0.256 (strong synergism) | 86.838 | 4.098 | ||
| 400:100 | 0.372 (synergism) | 567.143 | 2.700 | ||
| siDCLK-4/ VBL | 50:0.1 | 4.646 (strong antagonism) | 0.221 | 8.358 | |
| 100:1 | 0.545 (synergism) | 2.936 | 4.898 | ||
| 200:10 | 0.427 (synergism) | 14.823 | 2.781 | ||
| 400:100 | 0.576 (synergism) | 1.440E + 3 | 1.739 | ||