Thymoquinone (TQ) regulates cyclooxygenase-2 expression and prostaglandin E2 production through PI3kinase (PI3K)/p38 kinase pathway in human breast cancer cell line, MDA-MB-231

Thymoquinone (TQ), a drug extracted from the black seeds of Nigella sativa, has been shown to exhibit anti-inflammatory, anti-oxidant, and anti-neoplastic effects in numerous cancer cells. The effects of TQ on cyclooxygenase-2 (COX-2) expression and prostaglandin E₂(PGE₂) production in MDA-MB-231, however, remain poorly understood. Western blot analysis and immunofluorescence staining were performed to study the expression levels of inflammation regulatory proteins in MDA-MB-231. PGE₂ assay was conducted to explore the TQ-induced production of PGE₂. In this study, we investigated the effects of TQ on COX-2 expression and PGE₂ production in MDA-MB-231. TQ significantly induced COX-2 expression and increased PGE₂ production in a dose-dependent manner, as determined by a Western blot analysis and PGE₂ assay. Furthermore, the activation of Akt and p38 kinase, respectively, was up-regulated in TQ treated cells. Inhibition of p38 kinase with SB203580 and PI3kinase (PI3K) with LY294002 abolished TQ-caused COX-2 expression and decreased PGE₂ production. These results collectively demonstrate that TQ effectively modulates COX-2 expression and PGE₂ production via PI3K and p38 kinase pathways in the human breast cancer cell line MDA-MB-231.