Dopamine D1 receptors induce apoptosis of osteosarcoma cells via changes of MAPK pathway

Summary This study explored the effects and mechanisms of dopamine D1 receptors ( DR 1) activation on the apoptosis of osteosarcoma cells ( OS 732).The DR 1 agonist SKF ‐38393 decreased the viability of OS 732 cells and increased their rate of apoptosis, whereas the DR 1 antagonist SCH ‐23390 abolished the effects of SKF ‐38393. In OS 732 cells, overexpression of DR 1 increased the rate of apoptosis, caspase‐9 and ‐3 expression, and the release of cytochrome c (Cyt c ), reduced Bcl‐2 expression, inhibited extracellular signal‐regulated kinase 1/2 ( ERK 1/2) phosphorylation, and induced phosphorylation of p38 mitogen‐activated protein kinase (p38 MAPK ) and c‐Jun N‐terminal kinase ( JNK ). These results suggest that activation of DR 1 induces osteosarcoma cell apoptosis via changes to the MAPK pathway.