Membranous NOX5-derived ROS oxidizes and activates local Src to promote malignancy of tumor cells

Area of Science:

• Cell Biology
• Oncology
• Biochemistry

Background:

• Reactive oxygen species (ROS) regulate cellular signaling and tumor progression, especially under hypoxic stress.
• NADPH oxidases (NOXs) produce localized ROS, but their subcellular roles in hypoxic tumors remain elusive.
• Esophageal squamous cell carcinoma (ESCC) malignancy is influenced by environmental factors like hypoxia.

Purpose of the Study:

• To investigate the role and mechanism of NOX5 in the malignant progression of ESCC, particularly under hypoxic conditions.
• To explore the relationship between NOX5 expression, ESCC tumor malignancy, and patient prognosis.

Main Methods:

• Analysis of NOX5 expression in clinical ESCC tumors, cell lines, and primary cells.
• Investigating the molecular mechanism of NOX5 activation and its downstream signaling pathways under hypoxia.
• Utilizing techniques to study protein-protein interactions and phosphorylation events (e.g., Ca2+-mediated phosphorylation, c-Abl activity).

Main Results:

• NOX5 was significantly upregulated in ESCC tumors and cells, correlating with increased malignancy and poorer prognosis.
• NOX5 activation by hypoxia promotes ESCC progression through Src activation.
• Hypoxia facilitates NOX5-Pyk2 interaction via Ca2+-mediated Pyk2 phosphorylation, enabling c-Abl to phosphorylate NOX5, leading to ROS production and Src activation.

Conclusions:

• NOX5 plays a critical role in the development and progression of ESCC, especially under hypoxic stress.
• The NOX5-Pyk2-c-Abl-Src signaling axis is a key mechanism driving ESCC malignancy.
• Targeting NOX5 may offer a therapeutic strategy for ESCC.