7 research outputs found
Retinoid and thiazolidinedione therapies in melanoma: an analysis of differential response based on nuclear hormone receptor expression
<p>Abstract</p> <p>Background</p> <p>Metastatic melanoma has a high mortality rate and suboptimal therapeutic options. Molecular targeting may be beneficial using the rexinoid LGD1069, a retinoid Ć receptor selective agonist, and thiazolidinediones (TZD), PPARĪ³ selective ligands, as novel treatments.</p> <p>Results</p> <p>Mouse xenograft models with human melanoma cell lines [A375(DRO) or M14(5ā16)] were treated for 4 weeks with daily vehicle, RXR agonist (rexinoid, LGD1069, 30 mg/kg/d), PPARĪ³ agonist (TZD, rosiglitazone, 10 mg/kg/d) or combination. A375(DRO) tumor growth was significantly inhibited by either ligand alone and the combination had an additive effect. M14(5ā16) tumors only responded to LGD1069 100 mg/kg/day. A375(DRO) sublines resistant to rexinoid, TZD and combination were generated and all three sublines had reduced PPARĪ³ expression but preserved RXR expression. shRNA knockdown of PPARĪ³ or RXRĪ³ attenuated the rexinoid, TZD and combination ligand-mediated decreased proliferation in A375(DRO) cells. Rexinoid (LGD1069) and retinoid (TTNPB) treatment of M14(5ā16) cells resulted in decreased proliferation that was additive with combination of both rexinoid and retinoid. shRNA knockdown of RXRĪ³ resulted in a decreased response to either ligand.</p> <p>Conclusion</p> <p>A375 (DRO) melanoma cell growth is inhibited by rexinoid and TZD treatment, and this response is dependent on RXR and PPARĪ³ receptor expression. M14 (5ā16) melanoma cell growth is inhibited by rexinoid and retinoid treatment, and this response is dependent on RXR expression. These findings may help guide molecular-based treatment strategies in melanoma and provide insight for mechanisms of resistance to nuclear receptor targeted therapies in certain cancers.</p