Table 1.
Number of tumors formed in the different cell lines using serial dilutions of inoculated cells (limiting dilution assays). 8–18 independent biological replicates have been performed in the different conditions (1M: 18, 18, 15 eggs; 100K: 9, 10, 10 eggs; 10K: 10, 10, 10 eggs and 1K: 8, 10, 9 eggs for 231, 231.Br and 231.Br.HER2 respectively). Using the ELDA software (http://bioinf.wehi.edu.au/software/elda/), a stem cell frequency was determined. A significant difference was obtained between the parental 231 and the brain-tropic variants (231.Br and 231.Br.HER2), however no significant enrichment is observed for 231.Br vs. 231.Br.HER2.
| Cell Model | 1M | 100K | 10K | 1k | Stem Cell Frequency (ELDA) | p-Value (vs 231) * | p-Value ** |
|---|---|---|---|---|---|---|---|
| 231 | 18/18 (100%) | 5/9 (55.6%) | 2/10 (20%) | 3/8 (37.5%) | 1/68769 | - | 7.31 × 10−5 |
| 231.Br | 18/18 (100%) | 10/10 (100%) | 4/10 (40%) | 3/10 (30%) | 1/12215 | 0.0007 | |
| 231.Br.HER2 | 15/15 (100%) | 10/10 (100%) | 6/10 (60%) | 1/9 (11.1%) | 1/10535 | 0.0003 |
Multiple group statistical analysis: * Overall test for differences in stem cell frequencies between any of the groups; ** Pairwise tests for differences in stem cell frequencies.