Targeting ROS production through inhibition of NADPH oxidases.

Area of Science:

• Biochemistry
• Enzymology
• Cancer Biology

Background:

• NADPH oxidases (NOXs) are enzymes producing reactive oxygen species (ROS), crucial in cellular signaling.
• Dysregulated NOX activity and ROS imbalance contribute to cancer progression.
• Existing NOX inhibitors lack isoenzyme selectivity, leading to off-target effects.

Purpose of the Study:

• To identify and validate selective human NOX inhibitors.
• To target the active site of Cylindrospermum stagnale NOX5 (csNOX5).
• To explore the therapeutic potential of these inhibitors in cancer treatment.

Main Methods:

• In silico screening to identify potential NOX inhibitors.
• In vitro and in cellulo enzymatic and binding assays for validation.
• High-resolution crystal structures to study binding modes.
• High-throughput screening in cancer cell lines.

Main Results:

• Fully validated human NOX inhibitors targeting csNOX5 were identified.
• Inhibitors demonstrated binding to the dehydrogenase domain of csNOX5.
• Selected inhibitors showed activity in various cancer cell lines.
• Synergistic effects were observed when combined with KRAS modulators.

Conclusions:

• The study provides a foundation for developing isoenzyme-selective NOX inhibitors.
• These inhibitors offer a potential strategy for controlling localized ROS sources in cancer.
• The findings pave the way for novel cancer therapeutics with improved specificity.