Hepatic cancer stem cells and drug resistance: Relevance in targeted therapies for hepatocellular carcinoma

Table 2 Several potential inhibitors and targeted agents of growth factor receptors, signaling pathways and ABC transporters in liver cancer

Targets		Agents	Ref.
ABC transporters	ABCB1/MDR1	Verapamil, cyclosporine, GF120918, PSC833, GG918, biricodar	[146-149]
	ABCC1/MRP1	Cyclosporine, biricodar	[146,149]
	ABCG2/BCRP	FTC, Kol43, GF120918, novobiocin, naringenin	[69,70,147,150,151]
Growth factor receptors and signaling pathways	VEGF receptors	Sorafenib, sunitinib, bevacizumab	[139,142-145]
	EGF receptors	Erlotinib, gefitinib, cetuximab	[120-126]
	IGF receptors	IMC-A12	[132-134]
	Hedgehog pathway	Cyclopamine, anti-Rab23, SHH neutralizing antibodies	[107,108]
	Wnt/ β-catenin	Anti-Wnt antibody, AKT1 inhibitor	[34]
	Notch	TW-37	[136]

VEGF: Vascular endothelial growth factor; IGF: Insulin growth factor; EGF: Epidermal growth factor; ABC: ATP binding cassette.