Violacein improves vemurafenib response in melanoma spheroids

Area of Science:

• Biochemistry
• Cancer Biology
• Pharmacology

Background:

• Chemotherapy resistance poses a significant challenge in melanoma treatment.
• Violacein, a pigment from Chromobacterium violaceum, exhibits anti-tumor properties, including apoptosis induction in melanoma.
• BRAF-mutated melanoma is a common subtype with specific therapeutic vulnerabilities.

Purpose of the Study:

• To investigate violacein's potential as a sensitizer to improve vemurafenib efficacy in BRAF-mutated melanoma.
• To evaluate the impact of the violacein and vemurafenib combination (ViVe) on melanoma cell viability and key protein levels.
• To elucidate the molecular mechanisms underlying ViVe's sensitizing effect, focusing on p62 and fatty acid synthase (FASN).

Main Methods:

• Utilized BRAF-mutated melanoma spheroids and 2D cell culture systems.
• Assessed cell viability and death using calcein and ethidium homodimer staining.
• Quantified levels of p62 and fatty acid synthase (FASN) proteins.

Main Results:

• The ViVe combination demonstrated efficacy at subtoxic concentrations, interfering with melanoma spheroid survival.
• ViVe treatment significantly increased apoptosis rates in both spheroid and 2D melanoma cell models.
• Evidence suggests ViVe downregulates FASN, a crucial mediator, contributing to its sensitizing effect.

Conclusions:

• Violacein acts as a sensitizer, enhancing vemurafenib's effectiveness against BRAF-mutated melanoma.
• The ViVe combination offers a promising strategy to overcome chemotherapy resistance in melanoma.
• Downregulation of FASN by ViVe is a key mechanism contributing to improved therapeutic outcomes.