The Paradoxical Role of NKG2D in Cancer Immunity

Area of Science:

• Immunology
• Cancer Biology
• Oncology

Background:

• The NKG2D receptor and its ligands are crucial for immune responses against tumors and infections.
• NKG2D mediates antitumor functions on natural killer cells and T cells, crucial for cancer surveillance.
• NKG2D deficiency delays tumor development in mouse models, underscoring its antitumor role.

Purpose of the Study:

• To review the dual role of NKG2D in cancer immunity, focusing on inflammation-driven liver cancer.
• To discuss how the tumor microenvironment influences NKG2D-mediated immune responses.
• To explore the potential for NKG2D ligands to promote cancer progression in advanced cancers.

Main Methods:

• Review of current scientific literature on NKG2D-mediated tumor surveillance.
• Analysis of data from transgenic mouse models of inflammation-driven liver cancer.
• Postulation of mechanisms underlying the dual role of NKG2D in cancer immunity.

Main Results:

• NKG2D demonstrates potent antitumor surveillance functions in various cancer models.
• Unexpectedly, NKG2D was found to contribute to tumor growth in a model of inflammation-driven liver cancer.
• Ligand expression for NKG2D can drive cancer progression rather than rejection in certain advanced cancers.

Conclusions:

• NKG2D exhibits a dual role in cancer immunity, acting as both a tumor suppressor and promoter.
• The tumor microenvironment significantly impacts the outcome of NKG2D activation.
• In inflamed tissues, NKG2D can promote autoimmune-like tissue damage, facilitating tumor progression.