VHL loss enhances antitumor immunity by activating the anti-viral DNA-sensing pathway

Area of Science:

• Oncology
• Immunology
• Molecular Biology

Background:

• The von Hippel-Lindau (VHL) gene is a tumor suppressor frequently mutated in clear cell renal cell carcinoma (ccRCC).
• VHL loss typically causes cellular stress and metabolic changes by stabilizing hypoxia-inducible factors (HIFs), but its role in immune response is unclear.
• The precise mechanisms by which VHL alterations influence anti-tumor immunity remain to be fully elucidated.

Purpose of the Study:

• To investigate the impact of VHL loss on the efficacy of anti-programmed death 1 (PD1) immunotherapy.
• To elucidate the underlying molecular mechanisms by which VHL deficiency modulates anti-tumor immune responses.

Main Methods:

• Utilized multiple murine tumor models with VHL loss.
• Analyzed T cell-dependent immune responses.
• Investigated hypoxia-inducible factor (HIF) levels, mitochondrial function, and DNA leakage.
• Assessed cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway activation and type I interferon induction.

Main Results:

• VHL loss significantly enhanced the efficacy of anti-PD1 treatment in a T cell-dependent manner.
• VHL loss led to HIF1α/2α upregulation, decreased mitochondrial outer membrane potential, and cytoplasmic release of mitochondrial DNA.
• This mitochondrial damage triggered cGAS-STING pathway activation, resulting in increased type I interferon production.

Conclusions:

• VHL gene loss potentiates anti-tumor immunity and improves anti-PD1 therapy outcomes.
• The study reveals a novel mechanism where VHL loss-induced cellular stress activates the cGAS-STING pathway, boosting interferon production and enhancing anti-tumor immune surveillance.
• These findings offer mechanistic insights into VHL's role in modulating the tumor microenvironment and suggest potential therapeutic strategies targeting VHL-deficient tumors.