Down-regulation of argininosuccinate synthetase is associated with cisplatin resistance in hepatocellular carcinoma cell lines: implications for PEGylated arginine deiminase combination therapy

Table 1 Sensitivity of human HCC cell lines to ADI-PEG 20 and cisplatin treatment

Cell line	ASS1 level	ADI-PEG 20 IC₅₀(nM)	Cisplatin IC₅₀(μM)
Huh7	High	> 10^a	2.7 ± 0.3
Malhavu	High	No curve	3.3 ± 0.2
Huh6	High	No curve	2.9 ± 0.8
SNU182	High	No curve	1.3 ± 0.3
Hep3B	High	> 10^a	0.36 ± 0.02
PLC5	High	No curve	2.2 ± 0.3
HCC36	Medium	2.4 ± 0.3	2.9 ± 1.2
HepG2	Medium	1.4 ± 0.2	4.7 ± 0.4
Tong	Low	1.3 ± 0.1	>30^b
Sk-Hep1	Negative	1.1 ± 0.1	>30^b
SNU398	Negative	1.2 ± 0.1	23 ± 7.8

HCC cells were treated with various concentrations of either ADI-PEG 20 or cisplatin and the Promega luminescence assay was performed. IC₅₀ was calculated on replicates (n = 3 to 4, mean ± SD).
^aNo good IC₅₀ fit: approximately 25-30% loss of cell viability by 10 nM ADI-PEG 20.
^bNo good IC₅₀ fit: lower limit.

ISSN: 1471-2407