Altered Cd8+ T lymphocyte Response Triggered by Arginase 1: Implication for Fatigue Intensification during Localized...

Area of Science:

• Molecular Biology
• Cancer Research
• Immunology

Background:

• Cancer treatment-related fatigue is a common and debilitating side effect.
• Fatigue often intensifies during external-beam radiation therapy (EBRT).
• The molecular mechanisms driving fatigue intensification during EBRT are not well understood.

Purpose of the Study:

• To investigate the differentially expressed genes and proteins associated with fatigue intensification during EBRT.
• To explore the relationship between gene expression changes and patient-reported fatigue levels.
• To identify potential molecular targets for mitigating EBRT-induced fatigue.

Main Methods:

• Collected peripheral blood and fatigue scores (FACT-F) from 30 prostate cancer patients undergoing EBRT at baseline, midpoint, and endpoint.
• Analyzed gene expression using RNA from peripheral blood.
• Measured plasma arginase I and arginine levels using ELISA and liquid chromatography-tandem mass spectrometry.

Main Results:

• Fatigue scores significantly decreased (indicating increased fatigue) from baseline to midpoint and endpoint of EBRT.
• The gene encoding arginase type 1 (ARG1) was significantly upregulated from baseline to midpoint (fold change = 2.41, p<0.05).
• Upregulation of ARG1 was negatively correlated with absolute lymphocyte count in patients with high fatigue, suggesting an immunosuppressive mechanism via arginine deficiency and impaired T-cell proliferation.

Conclusions:

• External-beam radiation therapy-induced upregulation of arginase 1 (ARG1) may be a key mechanism in the intensification of cancer-related fatigue.
• The observed ARG1 upregulation leads to arginine deficiency, potentially causing immunosuppression and impairing lymphocyte function.
• These findings provide novel molecular insights into cancer treatment-related fatigue and suggest ARG1 as a potential therapeutic target.