Clinically relevant GABARAP deficiency abrogates bortezomib-induced immunogenic cell death in multiple myeloma

Area of Science:

• Oncology
• Cell Biology
• Immunology

Background:

• Multiple myeloma (MM) is a cancer of plasma cells.
• Bortezomib is a proteasome inhibitor used to treat MM.
• Immunogenic cell death (ICD) is a form of cell death that elicits an anti-tumor immune response.

Purpose of the Study:

• To investigate the role of GABA type A receptor-associated protein (GABARAP) in MM cell response to bortezomib.
• To determine the impact of GABARAP downregulation on autophagy and calreticulin exposure.
• To understand the effect of GABARAP deficiency on the immunogenicity of bortezomib-treated MM cells.

Main Methods:

• Analysis of GABARAP expression in MM cells.
• Assessment of autophagy flux in GABARAP-deficient MM cells.
• Measurement of surface calreticulin exposure on MM cells.
• Evaluation of immunogenic cell death markers.

Main Results:

• High-risk, poor-prognosis MM is characterized by GABARAP downregulation.
• GABARAP deficiency results in defective autophagy.
• GABARAP downregulation impairs surface calreticulin exposure.
• GABARAP-defective MM cells fail to undergo immunogenic cell death upon bortezomib treatment.

Conclusions:

• GABARAP plays a critical role in mediating autophagy and calreticulin exposure in MM cells.
• GABARAP downregulation is associated with resistance to bortezomib-induced immunogenic cell death.
• Targeting GABARAP may represent a therapeutic strategy to enhance the efficacy of bortezomib in MM.