TABLE 1.

Sorafenib synergizes with vorinostat to kill pancreatic tumor cells that is abolished by overexpression of c-FLIP-s

Pancreatic cancer (Mia Paca 2, PANC1, AsPc1) and hepatoma (HEP3B) cells were infected 12 h after plating at an approximate multiplicity of infection of 50 with either a control empty vector recombinant adenovirus (CMV) or a recombinant virus to express the caspase 8 inhibitor c-FLIP-s. Twenty-four hours after infection, infected cells were plated as single cells (250-1500 cells/well) in sextuplicate; 12 h after this plating, the infected cells were treated with vehicle (DMSO), sorafenib (3.0-6.0 μM), vorinostat (250-500 nM), or both drugs combined, as indicated, at a fixed concentration ratio to perform median dose-effect analyses for the determination of synergy. After drug exposure (48 h), the medium was changed, and cells were cultured in drug-free medium for an additional 10 to 14 days. Cells were fixed and stained with crystal violet, and colonies of >50 cells/colony were counted. Colony formation data were entered into the Calcusyn program, and combination index (CI) values were determined. A CI value of less than 1.00 indicates synergy.

Cell Lines & Treatments	Sorafenib	Vorinostat	Fa	CI
	μM	μM
Mia Paca2
CMV	3.00	0.250	0.34	0.32
	4.50	0.375	0.42	0.40
	6.00	0.500	0.50	0.45
c-FLIP-s	3.00	0.250	0.16	0.98
	4.50	0.375	0.21	1.23
	6.00	0.500	0.26	1.42
PANC1
CMV	3.00	0.250	0.22	0.38
	4.50	0.375	0.28	0.42
	6.00	0.500	0.36	0.38
c-FLIP-s	3.00	0.250	0.06	0.92
	4.50	0.375	0.10	1.00
	6.00	0.500	0.16	1.03
AsPc1
CMV	3.00	0.250	0.34	0.34
	4.50	0.375	0.48	0.40
	6.00	0.500	0.58	0.45
c-FLIP-s	3.00	0.250	0.06	1.08
	4.50	0.375	0.11	0.96
	6.00	0.500	0.19	0.77
Hep3B
CMV	3.00	0.250	0.43	0.47
	4.50	0.375	0.56	0.58
	6.00	0.500	0.74	0.58
c-FLIP-s	3.00	0.250	0.26	0.90
	4.50	0.375	0.40	0.97
	6.00	0.500	0.54	1.08