Table 2.

Potential effects of nuclear receptor ligands on osteosarcoma tumors.

	Ligand	Experimental Setup	Effect	Mechanism	Reference
PPARγ	Troglitazone	in vitro proliferation and apoptosis assays	inhibited proliferation	promotion of apoptosis, induce differentiation (alkaline phosphatase)	Haydon 2002, 2007 [9, 32]
	Ciglitazone	in vitro proliferation and apoptosis assays	minimal effect	unknown	Haydon2002 [32]
	Troglitazone	in vitro MTT proliferation and apoptosis assays	increased proliferation	inhibition of apoptosis	Lucarelli 2002 [170]
	Pioglitazone and PG J(2)	in vitro MTT and apoptosis assays of Chondrosarcoma Cells	inhibition of proliferation	promoted apoptosis	Nishida [171]
Retinoic Acid	9-cis retinoic acid	in vitro proliferation and apoptosis assays	inhibited proliferation	promotion of apoptosis	Haydon 2002, 2007 [9, 32]
Estrogen	17-beta estradiol, Ospemifene	U2OS expressing ER, in vitro apoptosis assays	opposed Etoposide-induced cell death	oppose increases in IL-6 and decreases in OPG, preventing osteoclast activation	Kallio 2008 [172]
	Tamoxifen, Raloxifene	U2OS expressing ER, in vitro apoptosis assays	no effect on Etoposide-induced cell death	unknown	Kallio 2008 [172]
	17-beta estradiol, SERMS (genistein, daidzein)	U2OS expressing ER, in vitro cell cycle, proliferation, apoptosis assays	inhibit proliferation, promote apoptosis	decrease EGFR, increased osteoblast maturation markers	Salvatori 2009 [173]
Vitamin D	1-alpha hydroxyvitamin D3	oral administration in Dunn murine OS model	inhibits tumor growth and metastasis	increased necrosis, no cell cycle mitotic index effects	Hara 2001 [174]
	Prolactin + 1,25 (OH)2 Vitamin D3	RT-PCR, western blots	PRL inhibits VDR expression in response to 1,25 (OH)2 Vitamin D3	VDR expression is dependent on BRCA1 expression	Deng [175]
	calcitriol	OS cells with increased RXR degradation, treated with calcitriol	increased expression of RXR restores anti-proliferative effects of calcitriol	calcitriol induced degradation is dependent on RXR expression	Prufer 2002 [176]