Sunitinib Induces NK-κB-dependent NKG2D Ligand Expression in Nasopharyngeal Carcinoma and Hepatoma Cells

Area of Science:

• Oncology
• Immunology
• Molecular Biology

Background:

• Multitargeted tyrosine kinase inhibitors (MTKIs) combined with natural killer (NK) cell therapy show promise in cancer treatment.
• MTKIs enhance NK cell therapy by upregulating natural killer group 2 member D ligands (NKG2DLs) on tumor cells.
• The precise molecular mechanism behind MTKI-induced NKG2DL upregulation remains unclear.

Purpose of the Study:

• To investigate the molecular mechanism by which sunitinib upregulates NKG2DLs.
• To determine the role of the nuclear factor-kappa B (NF-κβ) pathway in sunitinib's effect on NKG2DLs.
• To evaluate the impact of sunitinib on cancer cell sensitivity to NK cell cytotoxicity.

Main Methods:

• Sunitinib treatment of drug-resistant nasopharyngeal carcinoma (CNE2/DDP) and hepatoma (HepG2) cell lines.
• Assessment of sunitinib's effects on cell proliferation, apoptosis, and DNA damage.
• NK cell coculture experiments to measure activation and cytotoxicity.
• Quantitative polymerase chain reaction (qPCR) to analyze gene expression, including NKG2DLs and NF-κβ family genes.
• Gene silencing of NF-κβ pathway components (NF-κβ1, NF-κβ2, RelB).

Main Results:

• Sunitinib downregulated its known targets (VEGF, PDGF, c-kit) and induced apoptosis and DNA damage in cancer cells.
• Sunitinib-treated cancer cells enhanced NK cell activation and cytotoxicity.
• Sunitinib upregulated NKG2DLs, apoptotic genes, DNA damage repair genes, and NF-κβ family genes.
• Silencing of NF-κβ1, NF-κβ2, or RelB inhibited sunitinib-induced NKG2DL upregulation.

Conclusions:

• Sunitinib upregulates NKG2DLs through the noncanonical NF-κβ signaling pathway.
• This mechanism enhances the cytotoxic sensitivity of cancer cells (CNE2/DDP, HepG2) to NK cell therapy.
• The findings elucidate a key molecular mechanism for combining MTKIs with NK cell adoptive transfer in cancer treatment.