CYP27A1-dependent anti-melanoma activity of limonoid natural products targets mitochondrial metabolism

Area of Science:

• Biochemistry
• Molecular Biology
• Oncology

Background:

• Melanoma, particularly BRAF-mutant melanoma, remains a significant health challenge.
• Targeting tumor-specific metabolic vulnerabilities is a promising therapeutic strategy.
• The role of mitochondrial enzymes in cancer cell proliferation is an area of active research.

Purpose of the Study:

• To identify novel compounds with selective anti-proliferative activity against melanoma cell lines.
• To elucidate the molecular mechanism of action for these identified compounds.
• To explore a potential therapeutic strategy for BRAF-mutant melanoma.

Main Methods:

• High-throughput screening of natural products for anti-proliferative activity.
• Differential transcriptome analysis to identify genes associated with compound activity.
• Mitochondrial cytochrome P450 oxidase (CYP27A1) activity assays.
• Genome-wide small interfering RNA (siRNA) screening.
• Chemical proteomics for gene-drug interaction studies.

Main Results:

• Three limonoid natural products demonstrated selective anti-proliferative effects on BRAF(V600E) and NRAS(Q61K)-mutation-dependent melanoma cells.
• Compound activity was dependent on the expression of CYP27A1, a transcriptional target of the melanogenesis-associated transcription factor (MITF).
• CYP27A1 activity was essential for generating a reactive metabolite that inhibited cell proliferation.
• Functional epistasis indicated that compounds target mitochondrial biogenesis and inhibit tumor bioenergetics via a covalent mechanism.

Conclusions:

• A novel therapeutic strategy for melanoma involves targeting MITF-regulated CYP27A1.
• Inhibition of mitochondrial oxidative phosphorylation in BRAF-mutant melanomas is achievable with these compounds.
• Exploiting CYP27A1 dependency offers a pathway for melanoma-specific targeting.