p53 pathway determines the cellular response to alcohol-induced DNA damage in MCF-7 breast cancer cells

Abstract

Alcohol consumption is associated with increased breast cancer risk; however, the underlying mechanisms that contribute to mammary tumor initiation and progression are unclear. Alcohol is known to induce oxidative stress and DNA damage; likewise, p53 is a critical modulator of the DNA repair pathway and ensures genomic integrity. p53 mutations are frequently detected in breast and other tumors. The impact of alcohol on p53 is recognized, yet the role of p53 in alcohol-induced mammary carcinogenesis remains poorly defined. In our study, we measured alcohol-mediated oxidative DNA damage in MCF-7 cells using 8-OHdG and p-H2AX foci formation assays. p53 activity and target gene expression after alcohol exposure were determined using p53 luciferase reporter assay, qPCR, and Western blotting. A mechanistic study delineating the role of p53 in DNA damage response and cell cycle arrest was based on isogenic MCF-7 cells stably transfected with control (MCF-7/Con) or p53-targeting siRNA (MCF-7/sip53), and MCF-7 cells that were pretreated with Nutlin-3 (Mdm2 inhibitor) to stabilize p53. Alcohol treatment resulted in significant DNA damage in MCF-7 cells, as indicated by increased levels of 8-OHdG and p-H2AX foci number. A p53-dependent signaling cascade was stimulated by alcohol-induced DNA damage. Moderate to high concentrations of alcohol (0.1–0.8% v/v) induced p53 activation, as indicated by increased p53 phosphorylation, reporter gene activity, and p21/Bax gene expression, which led to G0/G1 cell cycle arrest. Importantly, compared to MCF-7/Con cells, alcohol-induced DNA damage was significantly enhanced, while alcohol-induced p21/Bax expression and cell cycle arrest were attenuated in MCF-7/sip53 cells. In contrast, inhibition of p53 degradation via Nutlin-3 reinforced G0/G1 cell cycle arrest in MCF-7 control cells. Our study suggests that functional p53 plays a critical role in cellular responses to alcohol-induced DNA damage, which protects the cells from DNA damage associated with breast cancer risk.

2,4,6-Trinitrotoluene Induces Apoptosis via ROS-Regulated Mitochondrial Dysfunction and Endoplasmic Reticulum Stress in HepG2 and Hep3B Cells

“…1B ); the presence of a DNA-forming tail-like structure in a concentration-dependent manner was observed in cells treated with TNT. Second, HepG2 and Hep3B cells were treated with different concentrations of TNT (HepG2: 0–30 μM; Hep3B: 0–50 μM) for 24 h to determine the induction of protein related to the DNA damage marker: γ-H2AX 18 . We found that TNT induces γ-H2AX in a concentration-dependent manner in HepG2 and Hep3B cells (Fig.…”

The protective effect of PFTα on alcohol-induced osteonecrosis of the femoral head

“…A similar finding was also observed in previous studies [ 14 ]. The use of the selective p53 activators Tenovin-1 and NSC207895 could increase the protein expression of p53 as well as its phosphorylation, indicating activation of the p53 pathway [ 22 ]. For downstream effectors, the decreased phosphorylation of GSK3β and β-catenin indicated that p53 activation partially mimicked the effect of ethanol on the p53/Wnt/β-catenin pathway in hBMSCs.…”

“…Moreover, knockout of the p53 gene in the mouse model resulted in enhanced osteogenesis [ 21 ]. A recent study demonstrated that ethanol could induce the activation of p53 in vitro [ 22 ]. Therefore, we consider that the p53 gene might be a critical mediator of ethanol-triggered anti-osteogenesis and may play a role in the development of alcohol-induced ONFH.…”

Untitled

“…The tumor suppressor protein p53 play an important part in the regulation of cellular response to DNA damage. It has been revealed to have a role in sensing oxidative DNA damage 25 and perhaps this can trigger p53 dependent apoptosis in zebrafish brain.…”