Table 1. IC50 values and combinatory index for treatment of p53-proficient and p53-deficient SCCHN cell lines with ATO and IR.
Cell line | p53 genotype | Class of mutation | p21 fold induction* | IC50 [μM ATO] | CI at ED75 (IR+ATO) | Effect |
UT-SCC-9 | Δ exon 2-9 | disruptive | 1.0 | 0.21 | 1.08 | additive |
UD-SCC-4 | c.449 del13 | frameshift | 1.0 | 2.41 | 0.86 | additive |
SCC9 | c.820 del32 | frameshift | 1.1 | 0.09 | 1.29 | antagonism |
UD-SCC-5 | H179Y | missense | 1.0 | 0.45 | 0.95 | additive |
UM-SCC-11B | C242S | missense | 1.0 | 0.31 | 0.98 | additive |
FaDu | R248L | missense | 0.9 | 0.36 | 1.04 | additive |
UM-SCC-25 | wt | – | 0.7 | 0.03 | 0.69 | synergism |
UD-SCC-2 | wt | – | 2.1 | 3.3 | 0.90 | additive |
UM-SCC-17B | wt | – | 2.0 | 4.5 | 1.00 | additive |
UM-SCC-74B | wt | – | 15.0 | 31.9 | 0.93 | additive |
*IR-induced p21 induction as a measure of p53 function was determined 4 hs after irradiation of cells with 6 Gy.