Role of estrogen receptor alpha in MEHP-induced proliferation and invasion of SH-SY5Y cells

Estrogen receptors are involved in regulating the proliferation and invasion process of neuroblastoma. As a kind of estrogen-like environmental endocrine disruptors (EEDs), whether mono-2-ethylhexyl phthalate (MEHP) can affect the proliferation and invasion of neuroblastoma cells via ERs is unknown. The present study aimed to explore the role of ERα in MEHP-induced proliferation, migration, and invasion of SH-SY5Y cells. SH-SY5Y cells were cultured in DMEM with 10 % FBS. Wild-type SH-SY5Y cells and ERα-knockdown SH-SY5Y cells were treated with MEHP (0, 10, 50, and 250 μM) for 12 h and 24 h. The viability of SH-SY5Y cells was detected with a CCK8 kit and cell cycle was measured by flow cytometry. Cell migration was measured using a scratch assay, and cell invasion was tested using a Transwell migration assay. The expression levels of proliferating cell nuclear antigen (PCNA), matrix metalloproteinase 2 (MMP-2), matrix metalloproteinase 9 (MMP-9), tissue inhibitor of matrix metalloproteinase 2 (TIMP-2), ERα, and ERβ were detected with real-time qPCR and western blotting. MEHP promoted the proliferation of SH-SY5Y cells. The results also showed that MEHP significantly increased the relative migration distance of wild-type SH-SY5Y cells. Conversely, MEHP treatment did not increase the relative migration distance of ERα-knockdown SH-SY5Y cells, suggesting that MEHP promotes the migration of neuroblastoma through ERα. Similarly, MEHP significantly increased the relative number of invaded wild-type SH-SY5Y cells, while the MEHP-induced invasion effect was significantly decreased in ERα-knockdown SH-SY5Y cells. Moreover, the expression levels of PCNA, MMP-2, MMP-9, and ERα cells were upregulated by MEHP in wild-type SH-SY5Y, and the expression level of its tissue inhibitor TIMP-2 was downregulated. In contrast, the expression of PCNA, MMP-2, MMP-9, and ERα was significantly downregulated in ERα-knockdown SH-SY5Y cells, while the expression of TIMP-2 was significantly upregulated. In conclusion, MEHP can upregulate PCNA, MMP-2, and MMP-9, and downregulate TIMP-2, further promoting proliferation, migration, and invasion of neuroblastoma through ERα.