Mitochondria as therapeutic targets for cancer stem cells

Table 1 Markers used to identify stem cells and cancer stem cells

Marker	Cancer origin	Marker properties	Ref.
ALDH1	Breast	Catalyzes the oxidation of aliphatic and aromatic aldehydes	[81]
		Converts retinol to retinoic acid
		AdSC
ABC135	Melanomas	ATP binding cassette family	[82]
		Involved in transport of sterol and other lipids
Bmi-1	Breast, prostate, leukemias, neuroblastomas	HSC, NSC, and AdSC marker	[83,84]
CD20	Metastatic melanomas	Hematopoietic marker	[85]
CD29	Breast, colon	AdSC marker	[86,87]
CD34	Leukemias, sarcomas	HSC, MSC marker	[88-91]
CD44	Breast, pancreas, colon, head and neck, prostate	Adhesion molecule related to metastasis	[91-96]
		HSC and pluripotent stem cell marker
		Normal prostate epithelial stem cell marker
CD49f	Prostate	Adhesion to extracellular matrix	[97]
CD90	Liver, breast, glioblastomas	Glycoprotein, role in stem cell differentiation	[98-100]
		MSC marker
CD113	Lung, pancreas, colon, glioblastoma, melanomas, etc.	HSC, NSC AdSC (colon) marker	[16-18,101-104]
CD117	Breast, ovarian, lung, glioblastoma	Progenitor cell marker	[105,106]
Oct4	Many carcinomas	Embryonic stem cell and induced pluripotent stem cell marker	[107,108]
Sca-1	Lung	Skin epithelial stem cell and HSC marker	[109]

AdSC: Adult stem cell marker; HSC: Hematopoietic stem cell; NSC: Neuronal stem cell; MSC: Mesenchymal stem cell.

Table 2 Mitochondrial features of cancer stem cells according to cancer origin

Cancer origin	Mitochondria features			Energy metabolism of CSC	Target/drug for CSCs	Ref.
	Feature	CSC	Non-CSC
Breast	Glucose uptake	High	Low	OXPHOS		[68]
	ATP contents	High	Low
	OCR	High	Low
	Lactate production	Low	High
	Membrane potential	High	Low
Glioma	Glucose consumption	Low	High	OXPHOS		[66]
	ATP contents	High	Low
	Lactate production	Low	High
	OCR	High	Low	OXPHOS	IMP-2	[67]
	ATP contents	High	Low
Leukemia	ROS	Low	High	Low glycolysis	Bcl-2/	[63]
	Proliferation rate	Slow	Fast	Low OXPHOS	ABT263
	OCR	Low	High
	Lactate production	Low	High
	ATP contents	Low	High
Lung	Glucose consumption	Low	High			[62]
	OCR	Low	High
	ROS level	Low	High
	ATP contents	Low	High
	Membrane potential	High	Low
	Mitochondrial DNA	Low	High
Ovarian					NV-128	[65]
	ROS	High	Low	OXPHOS		[64]
	Membrane potential	High	Low
	ATP contents	High	Low
	Glucose deprivation	Resist	Sensitive

CSC: Cancer stem cell; OCR: Oxygen consumption rate; ROS: Reactive oxygen species; OXPHOS: Oxidative phosphorylation; ABT263: Bcl-2 inhibitor; NV-128: Isoflavone derivative (play a role as inhibitor of mitochondrial function); IMP-2: Insulin-like growth factor 2 mRNA-binding protein 2.