Inhibition of PI3K/AKT molecular pathway mediated by membrane estrogen receptor GPER accounts for cryptotanshinone induced antiproliferative effect on breast cancer SKBR-3 cells

Abstract

Background: Breast cancer is the most frequently diagnosed malignancy among women and the second leading cause of cancer death worldwide. Among which nuclear estrogen receptor (nER) negative breast cancer is always with much poor prognosis. Recently, membrane G protein coupled estrogen receptor (GPER), a newly recognized estrogen receptor has been documented to take essential part in the development and treatment of breast cancer. The present study was designed to investigate the anti nER negative breast cancer effect of cryptotanshinone (CPT), an important active compound of traditional Chinese medicine Danshen and its possible molecular pathway. Methods: The following in vitro tests were performed in nER negative but GPER positive breast cancer SKBR-3 cells. The effect of CPT on cell proliferation rate and cell cycle distribution was evaluated by MTT cell viability test and flow cytometry assay respectively. The role of PI3K/AKT pathway and the mediated function of GPER were tested by western blot and immunofluorescence. Technique of gene silence and the specific GPER agonist G-1 and antagonist G-15 were employed in the experiments to further verify the function of GPER in mediating the anticancer role of CPT. Results: The results showed that proliferation of SKBR-3 cells could be blocked by CPT in a time and dose dependent manner. CPT could also exert antiproliferative activities by arresting cell cycle progression in G1 phase and down regulating the expression level of cyclin A, cyclin B, cyclin D and cyclin-dependent kinase 2 (CDK2). The antiproliferative effect of CPT was further enhanced by G-1 and attenuated by G-15. Results of western blot and immunofluorescence showed that expression of PI3K and p-AKT could be downregulated by CPT and such effects were mediated by GPER which were further demonstrated by gene silence test. Conclusion: The current study showed that the antiproliferative action of CPT on SKBR-3 cells was realized by inhibition of GPER mediated PI3K/AKT pathway. These findings provide further validation of GPER serving as useful therapeutic target.

Recent advances and future directions in anti‐tumor activity of cryptotanshinone: A mechanistic review

“…CT inhibits PI3K/Akt pathway in a dose‐ and time‐dependent manner. Also, inhibitory effect of CT on PI3K/Akt leads to stimulation of cell cycle arrest at G1 phase (Shi et al, 2020). IGF‐1R, as a upstream mediator, induces PI3K/Akt signaling pathway, while NF‐kB is a down‐stream target of PI3K/Akt that ensure proliferation of cancer cells.…”

Salvia miltiorrhiza in Breast Cancer Treatment: A Review of Its Phytochemistry, Derivatives, Nanoparticles, and Potential Mechanisms

“…In addition, CPT induced apoptosis in SKBR-3 ER-negative but G protein-coupled estrogen receptor (GPER)-positive breast cancer cells ( Shi et al, 2019 ). Further study confirmed that CPT did restrain SKBR-3 cell growth in a time- and dose-dependent manner ( Shi et al, 2020 ). According to recent studies, the inhibitory effect of CPT on the proliferation and migration of MCF-7 cells is much higher than on those of MDA-MB-231 cells, suggesting its effect was associated with ER expression ( Chen et al, 2020 ).…”

Staphylococcus aureus-Derived Extracellular Vesicles Enhance the Efficacy of Endocrine Therapy in Breast Cancer Cells

“…Phosphorylation of ERK is required for the binding of ER to the IGF−1 receptor [ 37 ]. In addition, the PI3K and p −AKT pathways are mediated by membrane G protein−coupled estrogen receptors [ 38 ]. In the present study, p −ERK and p −AKT levels were increased when S. aureus EVs were used in combination with tamoxifen compared to tamoxifen treatment alone.…”