TNF-α deficiency underlies NK cell dysfunction in colorectal cancer

Area of Science:

• Immunology
• Oncology
• Cell Biology

Background:

• Natural killer (NK) cells are crucial for innate antitumor immunity.
• NK cell function is often compromised in colorectal cancer (CRC) patients.

Purpose of the Study:

• To investigate the mechanisms of NK cell dysfunction in CRC.
• To identify systemic factors contributing to impaired NK cell activity in CRC patients.

Main Methods:

• Analysis of peripheral blood NK cell subsets (CD56+, CD56lowCD16+) in CRC patients and healthy donors (HD).
• Incubation of HD NK cells with CRC patient plasma to assess functional and signaling changes.
• Transcriptomic profiling of NK cells exposed to CRC plasma.
• Investigating the role of TNF-α signaling via inhibition and exogenous administration.

Main Results:

• CRC patients show reduced total CD56+ NK cells, a shift to CD56lowCD16+ subset, and impaired cytotoxic/cytokine responses.
• CRC plasma induces NK cell dysfunction in HD, suppressing mTORC1 and effector activity.
• Transcriptomics revealed downregulated TNF-α and JAK-STAT signaling, with upregulated SOCS genes in NK cells exposed to CRC plasma.
• TNF-α deficiency recapitulated CRC plasma-induced defects, while TNF-α supplementation partially restored NK cell function.

Conclusions:

• TNF-α signaling deficiency is a systemic mechanism suppressing NK cell function in CRC.
• Impaired NK cell metabolism and function in CRC contribute to immune evasion.
• Targeting the TNF-α axis could be a therapeutic strategy to enhance NK cell-mediated antitumor immunity in CRC.