In this study we hypothesized that thymoquinone suppresses LPS-induced COX-2 expression and PGE2 production in human lung cancer cells by upregulating microRNA-199a-3p, leading to inhibition of MAPK (p38, ERK, JNK) and NF-κB (p65/p50) signaling pathways. The gene discussed is PTGS2; the disease is lung carcinoma.