CCI-779 (Temsirolimus) exhibits increased anti-tumor activity in low EGFR expressing HNSCC cell lines and is effective in cells with acquired resistance to cisplatin or cetuximab

Table 1 Characteristics of HNSCC cell lines

Cell line	*TP53* genotype	p53 transcript	p53 protein	function	CCI-779 100 ng/ml
UT-SCC-23	Loss of transcript	-	-	-	95
UM-SCC-11B	missense mutation	+	+	-	87
UD-SCC-5	missense mutation	+	+	-	81
UD-SCC-4	delete, fs (stop codon)	+	-	-	70
UM-SCC-22B	missense mutation	+	+	-	64
SCC-9	delete, fs	+	+ (trunc.)	-	44
UM-SCC-17B	wt	+	+	+	38
UM-SCC-74B	wt	+	+	+	25
UT-SCC-15	Incorrectly spliced transcript, fs	+	+	-	16
UM-SCC-25	wt	(+)	-	-	16

Cell lines were ordered by their resistance to CCI-779 at 100 ng/ml. Presented are their TP53 genotype, transcript- and protein expression. P53 function was assessed by measuring p21 and porphobilinogen deaminase (PBGD) mRNA expression before and after irradiation, using a cut-off of 1.5 fold induction.

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