Proliferation and apoptosis regulation by G protein-coupled estrogen receptor in glioblastoma C6 cells

Coral Estefania Gutiérrez-Almeida; Anne Santerre; Lilia Carolina León-Moreno; Irene Guadalupe Aguilar-García; Rolando Castañeda-Arellano; Sergio Horacio Dueñas-Jiménez; Judith Marcela Dueñas-Jiménez

doi:10.3892/ol.2022.13338

Proliferation and apoptosis regulation by G protein-coupled estrogen receptor in glioblastoma C6 cells

Oncol Lett. 2022 May 18;24(1):217. doi: 10.3892/ol.2022.13338. eCollection 2022 Jul.

Authors

Coral Estefania Gutiérrez-Almeida¹, Anne Santerre², Lilia Carolina León-Moreno³, Irene Guadalupe Aguilar-García³, Rolando Castañeda-Arellano⁴, Sergio Horacio Dueñas-Jiménez³, Judith Marcela Dueñas-Jiménez¹

Affiliations

¹ Department of Physiology, University Center of Health Sciences, University of Guadalajara, Guadalajara, 44340 Jalisco, Mexico.
² Department of Cellular and Molecular Biology, University Center of Biological and Agricultural Sciences, University of Guadalajara, Zapopan, 45510 Jalisco, Mexico.
³ Department of Neuroscience, University Center of Health Sciences, University of Guadalajara, Guadalajara, 44340 Jalisco, Mexico.
⁴ Department of Biomedical Sciences, University Center of Tonala, University of Guadalajara, Tonala, 45425 Jalisco, Mexico.

Abstract

Glioblastoma is the most frequent primary tumor in the human brain. Glioblastoma cells express aromatase and the classic estrogen receptors ERα and ERβ and can produce estrogens that promote tumor growth. The membrane G protein-coupled estrogen receptor (GPER) also plays a significant role in numerous types of cancer; its participation in glioblastoma tumor development is not entirely known. The present study investigated the effect of the agonists [17β-estradiol (E2) and G1] and antagonist (G15) of GPER on proliferation and apoptosis of C6 glioblastoma cells. GPER expression was evaluated by immunofluorescence, western blotting and reverse transcription-quantitative PCR. Cell proliferation was determined using Ki67 immunopositivity. Cell viability was examined using the MTT assay and apoptosis using caspase-3 immunostaining and ELISA. C6 cells express GPER, and the immunopositivity increased after exposure to E2, G1, or their combination. GPER protein expression increased after treatment with E2 combined with G1. However, GPER mRNA expression decreased in treated cells compared with control. The percentage of Ki67 immunopositive C6 cells increased under the effect of E2 in combination with G1 or G1 alone. G15 significantly reduced Ki67 immunopositivity. Pearson's correlation analysis revealed a positive relationship between GPER and Ki67 immunopositivity across the study conditions. Additionally, the MTT assay showed a significant reduction in C6 cell viability after G15 treatment, alone or in combination with G1. The exposure to G15 increased the percentage of caspase-3 immunopositivity cells and caspase-3 levels. Pearson's correlation analysis demonstrated a negative correlation between GPER and caspase-3 immunopositivity across the study conditions. Glioblastoma C6 cells express GPER, and this receptor modulates cell proliferation and apoptosis. The GPER agonists E2 and G1 favored cell proliferation; meanwhile, the antagonist G15 reduced cell proliferation, viability and favored apoptosis. Therefore, GPER may be used as a biomarker of glioblastoma and as a target to develop new therapeutic strategies for glioblastoma treatment.

Keywords: G protein-coupled estrogen receptor; apoptosis; estrogen receptors; glioblastoma; proliferation.

Grants and funding

The present study was supported by the Programa de Apoyo a la Mejora en las Condiciones de Producción SNI y SNCA (PROSNI, 259639) from the University of Guadalajara, Mexico.