The integrated stress response and proteotoxicity in cancer therapy

Area of Science:

• Molecular Biology
• Cellular Stress Response
• Cancer Therapeutics

Background:

• Cellular stress, including protein misfolding and aggregation, leads to proteotoxicity.
• The integrated stress response (ISR) is a cytoprotective mechanism involving four kinases converging on the translation initiation factor eIF2α.
• Phosphorylation of eIF2α at S51 causes cell cycle arrest, inhibits protein synthesis, and modulates ATF4 translation, impacting cell fate.

Purpose of the Study:

• To provide an overview of the integrated stress response mechanisms.
• To discuss how inter-tumor heterogeneity in ISR affects sensitivity and resistance to proteasome inhibitors.
• To highlight the role of ISR in cancer therapeutics.

Main Methods:

• Review of existing literature on integrated stress response and proteotoxicity.
• Analysis of mechanisms linking ISR to proteasome inhibitor efficacy.
• Discussion of inter-tumor heterogeneity in the context of cancer therapy.

Main Results:

• The ISR involves eIF2α phosphorylation, leading to cell cycle arrest and altered protein synthesis.
• ISR activation can promote or inhibit apoptosis, depending on context.
• Inter-tumor heterogeneity in ISR pathways influences patient response to proteasome inhibitors.

Conclusions:

• The integrated stress response is a critical cellular defense against proteotoxicity.
• Understanding ISR heterogeneity is crucial for predicting and overcoming resistance to proteasome inhibitors.
• ISR modulation represents a potential strategy for enhancing cancer therapy.