Targeting the lipid kinase PIKfyve upregulates surface expression of MHC class I to augment cancer immunotherapy

Area of Science:

• Immunology
• Oncology
• Cell Biology

Background:

• Immunotherapies show success but face resistance in many cancer patients.
• PIKfyve regulates autophagic flux and lysosomal biogenesis.
• Upregulating MHC-I expression is crucial for effective anti-cancer T cell responses.

Purpose of the Study:

• To investigate the role of PIKfyve in regulating MHC-I expression and anti-cancer immunity.
• To determine if inhibiting PIKfyve can enhance the efficacy of cancer immunotherapies.

Main Methods:

• Genetic depletion and pharmacologic inhibition of PIKfyve in cancer cells and mouse models.
• Assessment of surface MHC-I expression using flow cytometry.
• Evaluation of CD8+ T cell infiltration and function within tumors.
• Testing the efficacy of PIKfyve inhibition in combination with immune checkpoint blockade, adoptive cell therapy, and therapeutic vaccines.

Main Results:

• PIKfyve inhibition, via genetic or pharmacologic means, increased surface MHC-I expression on cancer cells.
• This led to enhanced CD8+ T cell-mediated cancer cell killing and slowed tumor progression in mouse models.
• PIKfyve inhibition improved responses to multiple forms of immunotherapy and was dependent on CD8+ T cells and MHC-I.
• High PIKFYVE expression correlated with poor response to immune checkpoint blockade and survival.

Conclusions:

• Targeting PIKfyve enhances anti-tumor immunity by upregulating cancer cell MHC-I expression.
• PIKfyve inhibition represents a promising strategy to overcome immunotherapy resistance.
• PIKfyve inhibitors could be developed as agents to improve patient responses to existing immunotherapies.