GPER1 is regulated by insulin in cancer cells and cancer-associated fibroblasts.

Abstract

Elevated insulin levels have been associated with an increased cancer risk as well as with aggressive and metastatic cancer phenotypes characterized by a poor prognosis. Insulin stimulates the proliferation, migration, and invasiveness of cancer cells through diverse transduction pathways, including estrogen signaling. As G protein estrogen receptor 1 (GPER1) mediates rapid cell responses to estrogens, we evaluated the potential of insulin to regulate GPER1 expression and function in leiomyosarcoma cancer cells (SKUT-1) and breast cancer-associated fibroblasts (CAFs), which were used as a model system. We found that insulin transactivates the GPER1 promoter sequence and increases the mRNA and protein expression of GPER1 through the activation of the PRKCD/MAPK1/c-Fos/AP1 transduction pathway, as ascertained by means of specific pharmacological inhibitors and gene-silencing experiments. Moreover, cell migration triggered by insulin occurred through GPER1 and its main target gene CTGF, whereas the insulin-induced expression of GPER1 boosted cell-cycle progression and the glucose uptake stimulated by estrogens. Notably, a positive correlation between insulin serum levels and GPER1 expression was found in cancer fibroblasts obtained from breast cancer patients. Altogether, our data indicate that GPER1 may be included among the complex network of transduction signaling triggered by insulin that drives cells toward cancer progression.

• Authors: Paola De Marco, Enrica Romeo, Adele Vivacqua, Roberta Malaguarnera, Sergio Abonante, Francesco Romeo, Vincenzo Pezzi, Antonino Belfiore, Marcello Maggiolini
• Journal: Endocrine-related cancer (Endocr Relat Cancer) Vol. 21 Issue 5 Pg. 739-53 (Oct 2014) ISSN: 1479-6821 [Electronic] England
• PMID: 25012984 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2014 Society for Endocrinology.

Chemical References

• GPER1 protein, human
• GPER1 protein, mouse
• Insulin
• Proto-Oncogene Proteins c-fos
• Receptors, Estrogen
• Receptors, G-Protein-Coupled
• Transcription Factor AP-1
• Glucose

Topics

• Animals
• Cell Cycle (physiology)
• Cell Line
• Cell Line, Tumor
• Cell Movement
• Cells, Cultured
• Fibroblasts (drug effects, metabolism, physiology)
• Glucose (metabolism)
• Humans
• Insulin (metabolism)
• Mice
• Neoplasms (metabolism)
• Proto-Oncogene Proteins c-fos (metabolism)
• Receptors, Estrogen (genetics, metabolism)
• Receptors, G-Protein-Coupled (genetics, metabolism)
• Transcription Factor AP-1 (genetics, metabolism)