PTGER4 and non-small cell lung carcinoma: In vitro treatment of NSCLC cells (A549, H1299, H460, H226, and H157) with GSPs resulted in significant growth inhibition and induction of apoptosis, which were associated with the inhibitory effects of GSPs on the overexpression of COX-2 and prostaglandin (PG) E2 receptors (EP1 and EP4) in these cells [77].