Progesterone receptor and SRC-1 participate in the regulation of VEGF, EGFR and Cyclin D1 expression in human astrocytoma cell lines

Astrocytomas are the most common primary brain tumors in humans. It has been reported that vascular endothelial growth factor (VEGF), epidermal growth factor receptor (EGFR), cyclin D1 and progesterone receptor (PR) expression levels are elevated in patients with high-grade astrocytomas. Progesterone (P) regulates astrocytomas growth through its interaction with PR, which recruits coregulatory proteins such as steroid receptor coactivator-1 (SRC-1) that are required for efficient transcriptional activation. The regulation of VEGF, EGFR and cyclin D1 expression by P in human astrocytoma cells is not known. We studied the role of PR and SRC-1 in the expression of VEGF, EGFR and cyclin D1 mediated by P in human astrocytoma cell lines grade III (U373) and IV (D54). P significantly increased VEGF and EGFR mRNA expression after 12 h of treatment in D54 cells that was reflected at protein level 24 h after treatment. This effect was blocked by the PR antagonist, RU 486. In U373 cells cyclin D1 mRNA and protein expression was induced by P after 6 and 8 h of treatment, respectively, and this effect was blocked with RU 486. Transfection with short hairpin RNA targeting coactivator SRC-1 significantly reduced VEGF expression after 24 h of treatment. Collectively, our results indicate that P regulates VEGF and EGFR expression in D54 cells and cyclin D1 expression in U373 through PR, and that SRC-1 participates in the regulation of VEGF expression.

► Expression of VEGF, EGFR and cyclin D1 is regulated by progesterone in astrocytomas.
► Effect of progesterone on VEGF, EGFR and cyclin D1 are via its intracellular receptor.
► SRC-1 is required for progesterone-induced VEGF expression in human astrocytomas.