Up-regulation of 15-lipoxygenase enzymes and products in functional and non-functional pituitary adenomas.

Background: Pituitary adenoma accounts as a complex and multifactorial intracranial neoplasm with wide range of clinical symptoms which its underlying molecular mechanism has yet to be determined. The bioactive lipid mediators received attentions toward their contribution in cancer cell proliferation, progression and death. Amongst, 15-Lipoxygense (15-Lox) enzymes and products display appealing role in cancer pathogenesis which their possible effect in pituitary adenoma tumor genesis is perused in the current study.

Methods: The 15-Lipoxygenses isoforms expression level was evaluated in tumor tissues of prevalent functional and non-functional pituitary adenomas and normal pituitary tissues via Real-Time PCR. The circulating levels of 15(S) HETE and 13(S) HODE as 15-Lox main products were assessed in serum of patients and healthy subjects using enzyme immunoassay kits.

Results: Our results revealed that 15-Lox-1 and 15-Lox-2 expression levels were elevated in tumor tissues of pituitary adenomas comparing to normal pituitary tissues. The elevated levels of both isoforms were accompanied with 15(S) HETE and 13(S) HODE elevation in the serum of patients. The 15-Lox-1 expression and activity was higher in invasive tumors as well as tumors with bigger size indicating the possible pro-tumorigenic role of 15-Lox-1, more than 15-Lox-2 in pituitary adenomas. The diagnostic value of 15-Lipoxygense isoforms and products were considerable between patients and healthy groups.

Conclusion: The possible involvement of 15-Lipoxygense pathway especially 15-Lox-1 in the regulation of pituitary tumor growth and progression may open up new molecular mechanism regarding pituitary adenoma pathogenesis and might shed light on its new therapeutic strategies.