The role of dual‑specificity phosphatase 1 and protein phosphatase�1 in β2‑adrenergic receptor‑mediated inhibition of extracellular signal regulated kinase 1/2 in triple negative breast cancer cell lines

Abstract

Triple negative breast cancer cell lines express high levels of β2-adrenergic receptor, which have a significant influence on the activity of extracellular signal‑regulated kinase (ERK)1/2. Therefore, it is important to understand the link between β2‑adrenergic receptor signaling and ERK1/2 activity in terms of cancer cell regulation and cancer progression. Although the molecular mechanisms are not completely clarified, β2‑adrenergic receptor stimulation appears to reduce the basal levels of phosphorylated (p)ERK1/2 in MDA‑MB‑231 breast cancer cells. The aim of the current study was to determine the mechanism of β2‑adrenergic receptor‑mediated ERK1/2 dephosphorylation by investigating the role of dual‑specificity phosphatase (DUSP)1/6 and protein phosphatase (PP)1/2, which are established regulators of ERK1/2 phosphorylation, in MDA‑MB‑231 and MDA‑MB‑468 breast cancer cell lines. (E)‑2‑benzylidene‑3‑(cyclohexyl​amino)‑2,3‑ dihydro‑1H‑inden‑1‑one (BCI) and calyculin A were employed as DUSP1/6 and PP1/PP2 inhibitors, respectively. Subsequently, the protein levels of DUSP1, PP1, pPP1, ERK1/2 and pERK1/2 were measured by western blot analysis. Cells were transfected with DUSP1 small interfering (si)RNA or PP1 siRNA to inhibit their expression. The results demonstrated that β2‑adrenergic receptor agonists led to the dephosphorylation of basal pERK1/2 in MDA‑MB‑231 and MDA‑MB‑468 cells. The DUSP1/6 inhibitor, BCI, and the PP1/PP2 inhibitor, calyculin A, antagonized the β2‑adrenergic receptor‑mediated dephosphorylation of ERK1/2. Furthermore, β2‑adrenergic receptor stimulation increased the protein expression level of DUSP1, with no effects on DUSP6, PP1 and PP2 expression, and enhanced the expression of the active form of PP1. Downregulation of the expression of DUSP1 or PP1 led to a decline in the β2‑adrenergic receptor‑mediated dephosphorylation of ERK1/2. The results of the present study indicate that β2‑adrenergic receptor‑mediated dephosphorylation of ERK1/2 may be associated with the activity of DUSP1 and PP1 in MDA‑MB‑231 and MDA‑MB‑468 triple negative breast cancer cell lines. The clinical importance of β2‑adrenergic receptor‑mediated inactivation of ERK1/2 as well as the activation of DUSP1 and PP1 should be carefully evaluated in future studies, particularly when β2‑adrenergic blockers are used in patients with triple negative breast cancer.

Overexpression of β-Arrestins inhibits proliferation and motility in triple negative breast cancer cells

“…Cell cycle assays were performed using Annexin V FITC (640906, BioLegend, San Diego, CA, USA), propidium iodide staining kit (411301, BioLegend, SanDiego, CA, USA) and NovoCyte Flow cytom-Protein isolation and Western blotting. Protein isolation and Western blotting were carried out as described previously 27 . The cells in 6 well plates were immediately placed on ice, washed with ice-cold PBS, and homogenized in 100 μl lysis buffer (Roche Diagnostics GmbH, Mannheim, Germany) containing 1% Nonidet P40, 0.02 M sodium orthovanadate, and protease inhibitors.…”

Exploration of Tumor Microenvironment-Related Biomarkers for the Prognosis of Triple Negative Breast Cancer

“…We identi ed eight TME-related genes (ACAP1, DUSP1, LYZ, GZMA, SASH3, CCL5, CD74, DPT). The expression levels of these genes in TNBC patients had signi cant correlations with poor prognosis, indicating that our huge data analysis via ESTIMATE algorithm on the cBioPortal were greatly successful [31][32][33][34]. Among these eight genes, we are particularly interested in ACAP1, DUSP1, and GZMA.…”

Chemical-Genetic Interrogation of Nuclear Size Control Reveals Cancer-Specific Effects on Cell Migration and Invasion

“…Interestingly, BAAs suppress the epithelial to mesenchymal transition of bronchial epithelial cells and have been used to treat lung cancer 54,55 . BAAs also inhibit cancer pathways for triple-negative breast cancer and gliomas 56,57 , and the agonist salbutamol reduces migration and invasion of breast cancer cells 58 . Tissuespecific context for BAAs may be critically important, however; for example, beta-adrenergic receptor signaling promotes angiogenesis of gastric tumors 59 .…”