Table 2.
Focus assays after transfection with plasmids containing various SV40 constructs with or without asbestos
| Cell line | Treatment | Frequency of focus formation* | |
|---|---|---|---|
| Mesothelial cells | Asbestos fibers | —† | |
| Fibroblasts | Asbestos fibers | — | |
| Mesothelial cells | Transfection T+t+ | 4.6 × 10−4 ± 0.53 × 10−4 | |
| Fibroblasts | Transfection T+t+ | 6 × 10−6 ± 2.06 × 10−6 | |
| Mesothelial cells | Transfection T+t− | — | |
| Fibroblasts | Transfection T+t− | — | |
| Mesothelial cells | Transfection T+t+ and asbestos | 6 × 10−4 ± 3.46 × 10−4 | |
| Fibroblasts | Transfection T+t+ and asbestos | 9.3 × 10−6 ± 0.66 × 10−6 | |
| Mesothelial cells | Transfection T+t− and asbestos | 4 × 10−4 ± 2.31 × 10−4 | |
| Fibroblasts | Transfection T+t− and asbestos | 3.6 × 10−6 ± 0.88 × 10−6 |
*
Number of transformed foci per treated cell.
†
No foci developed from 107 cells exposed to asbestos. In addition, no foci developed from 107 cells transfected with the plasmids T−t+, or T−t− with or without asbestos, or from control cells. The following plasmids were used: pw2, expressing both Tag and tag (T+t+); pw2dl, which expresses Tag alone (T+t−); pw2t, which expresses tag alone (T−t+); and pw101, the negative control, expressing only a mutated tag that is biologically inactive because it does not bind protein phosphatase 2A (18) (T−t−).