Cyclooxygenase enzyme and PGE2 expression in patients with functional and non-functional pituitary adenomas

Pituitary adenomas as multifactorial intracranial neoplasms impose a massive burden of morbidity on patients and characterizing the molecular mechanism underlying their pathogenesis has received considerable attention. Despite the appealing role of cyclooxygenase enzymes and their bioactive lipid products in cancer pathogenesis, their relevance to pituitary adenoma pathogenesis is debated and yet to be determined. Thus, the current study perused this relevance.

The expression level of the isoforms of cyclooxygenase (COX-1 and COX-2) was evaluated in hormone-secreting and in-active pituitary adenoma tumors and normal pituitary tissues through Real-Time PCR. The level of PGE2, as the main product of enzymes, was assessed using enzyme immunoassay kits in patients and healthy subjects.

The results of the current study demonstrated that COX-1 and COX-2 expression levels were increased in pituitary tumors including non-functional pituitary adenoma (NFPA), acromegaly, Cushing's disease and prolactinoma compared with normal pituitary tissues. A significant expression level of COX-2 was observed in NFPA compared with the other pituitary tumors. Furthermore, the COX-2 expression level was significantly increased in macroadenoma and invasive tumors. The level of PGE2 was consistent with COX enzymes enhanced in pituitary adenoma tumors compared with healthy pituitary tissue. A significant elevation in the PGE2 level was detected in NFPA compared with hormone-secreting pituitary tumors. Additionally, the PGE2 level was increased in macroadenoma compared with microadenoma and in invasive compared with non-invasive pituitary tumors. The diagnostic values of cyclooxygenase isoforms and PGE2 were considerable between patients and healthy groups; however, COX-2 revealed more value in distinguishing endocrinologically active and non-active pituitary tumors.

Data from the current study provides expression patterns of COX-1, COX-2 and PGE2 in prevalent pituitary tumors and their association with patients' clinical features which may open up new molecular targets for early diagnosis/follow up of pituitary tumor growth.