STAT3 Regulates the Redox Profile in MDA-MB-231 Breast Cancer Cells

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Constitutive STAT3 activation and imbalanced redox status are linked to aggressive tumor biology, including metastasis and drug resistance in cancers.
• Triple-negative breast cancer (TNBC) is an aggressive subtype with a poor prognosis, where the role of STAT3 in redox homeostasis remains unclear.
• While STAT3 activation by reactive oxygen species (ROS) is known, its influence on redox balance in TNBC requires investigation.

Purpose of the Study:

• To investigate the role of STAT3 signaling in regulating redox balance within triple-negative breast cancer (TNBC) cells.
• To determine the impact of STAT3 inhibition on key redox homeostasis markers and associated signaling pathways in TNBC.

Main Methods:

• STAT3 was inhibited in TNBC cells.
• Levels of total ROS, hydroperoxides, nitric oxide (NO), and total glutathione (GSH) were measured.
• Expression of 3-nitrotyrosine (3NT), Nrf2, and NF-κB/p65 was assessed.
• TCGA data analysis correlated STAT3 mRNA and signature with NF-κB/p65 and Nrf2 signatures in TNBC patients.

Main Results:

• STAT3 inhibition affected ROS levels, with unchanged hydroperoxide levels but increased NO and 3NT expression.
• STAT3 inhibition led to decreased levels of GSH, Nrf2, and NF-κB/p65 protein.
• Correlations were observed between STAT3, NF-κB/p65, and Nrf2 signatures in TNBC patient data.

Conclusions:

• STAT3 signaling plays a significant role in controlling the redox balance in triple-negative breast cancer.
• STAT3 regulates the expression of redox-related genes, including those involved in oxidative stress response and inflammation.
• These findings highlight STAT3 as a potential therapeutic target for modulating redox status in TNBC.