TGF-β-driven NK Cells plasticity in hepatocellular carcinoma

Area of Science:

• Immunology
• Oncology
• Molecular Biology

Background:

• Hepatocellular carcinoma (HCC) is a major cause of cancer mortality with limited treatment options for advanced stages.
• Natural Killer (NK) cells are crucial for innate immunity but are suppressed within the tumor immune microenvironment (TIME) by factors like transforming growth factor-beta (TGF-β).

Purpose of the Study:

• To investigate the role of TGF-β signaling in altering NK cell phenotypes and functions within the HCC tumor immune microenvironment.
• To assess the impact of TGF-β pathway activation on NK cells, tumor-infiltrating lymphocytes (TILs), and liver-infiltrating lymphocytes (LILs) in HCC patients.

Main Methods:

• Isolation of TILs and LILs from HCC patients undergoing resection.
• Phenotypic and functional analysis of NK cells.
• Functional restoration experiments targeting TGF-β signaling pathways.

Main Results:

• Tumor-infiltrating NK cells (TINKs) showed activation of both canonical (SMAD-dependent) and non-canonical (TAK1/p38 MAPK) TGF-β signaling.
• A distinct ILC1-like NK subset (CD103+/CD49a+) emerged in tumors, expressing inhibitory receptors, while conventional NK cells (cNKs) were functionally impaired.
• Blocking TGF-β receptor binding and SMAD3 activation successfully restored cNK functionality.

Conclusions:

• Non-canonical TGF-β signaling contributes to NK cell dysfunction and phenotypic changes in HCC.
• Canonical SMAD-dependent TGF-β signaling is a viable therapeutic target for restoring NK cell function.
• Targeted inhibition of TGF-β pathways may enhance innate anti-tumor immunity, presenting novel combination therapy options for HCC.