Oncolytic viruses against cancer stem cells: A promising approach for gastrointestinal cancer

Table 1 Cancer stem cell markers of different gastrointestinal cancers

Cancer types	CSC markers	Ref.
Gastric cancer	CD44, CD133, Lgr5, STAT3, Aquaporin 3	[15,17,18]
Liver cancer	CD133, CD90, EpCAM, OV6, CD44, Nanog	[22]
Pancreatic cancer	CD133, CD24, CD44, EpCAM, ESA, c-Met, Aldh1, DclK1, Lgr5	[24,25]
Colorectal cancer	CD133, CD166, CD44, CD24, b1 integrin-CD29, Lgr5, EpCAM, ALDH1, Msi-1, EphB	[32-34]

CSC: Cancer stem cell; Lgr5: Leucine-rich repeat-containing G-protein coupled receptor 5; STAT3: Signal transducer and activator of transcription 3; EpCAM: Epithelial cell adhesion molecule; ESA: Epithelial-specific antigen; Alkh1: Aldehyde dehydrogenase 1; DclK1: Doublecortin-like kinase-1; Msi-1: Musashi-1; EphB: Ephrin-B.

Table 2 Oncolytic viruses against gastrointestinal cancer stem cell

Oncolytic viruses	Cancer types	CSC source	Effect	Description	Ref.
Adenovirus	Liver	CL	Susceptible	GP73 needed	[40]
	Pancrease, prostate	PC	Susceptible	Tat-PTD modified hexon and Ad5/35	[42]
	Gastric	CL	Mixed	AChE	[43]
	Gastric	CL	Susceptible	OBP-301, telomerase-specific	[44]
HSV2	Colon	CL	Susceptible	No virus modification or co-therapies	[47]
Vaccinia	Colon	CL	Mixed	Viral TK deficiency	[56]
Measles virus	HCC, colon	PX	Susceptible	Retargeted to CD133	[68]

CL: Cell line-derived spheres or cell lines sorted by marker expression; GP73: Golgi protein 73; HCC: Hepatocellular carcinoma; HSV: Herpes simplex virus; PX: Primary xenograft; PC: Primary cancer cells sorted by marker expression; Tat-PTD: Protein transduction domain (PTD) from the HIV-1 Tat protein; AChE: Acetylcholinesterase; TK: Thymidine kinase; NDV: Newcastle disease virus.