The nuclear factor-κB pathway down-regulates expression of the NKG2D ligand H60a in vitro: implications for use of nuclear factor-κB inhibitors in cancer therapy.
NKG2D ligands are cell surface proteins that activate NKG2D, a receptor used by natural killer (NK) cells to detect virus-infected and transformed cells. When tumour cells express high levels of NKG2D ligands, they are rejected by the immune system. Hence, reagents that increase NKG2D ligand expression on tumour cells can be important for tumour immunotherapy. To identify genes that regulate the NKG2D ligand H60a, we performed a microarray analysis of 3'-methylcholanthrene-induced sarcoma cell lines expressing high versus low H60a levels. A20, an inhibitor of nuclear factor-κB (NF-κB) activation, was differentially expressed in H60a-hi sarcoma cells. Correspondingly, treatment of tumour cells with inhibitors of NF-κB activation, such as sulfasalazine (slz), BAY-11-7085, or a non-phosphorylatable IκB, led to increased levels of H60a protein, whereas transduction of cells with an active form of IκB kinase-β (IKKβ) led to decreased levels of H60a. The regulation probably occurred at the transcriptional level, because NF-κB pathway inhibition led to increased H60a transcripts and promoter activity. Moreover, treatment of tumour cells with slz enhanced their killing by NK cells in vitro, suggesting that NF-κB inhibition can lead to tumour cell rejection. Indeed, when we blocked the NF-κB pathway specifically in tumour cells, there was decreased tumour growth in wild-type but not immune-deficient mice. Our results suggest that reagents that can block NF-κB activity specifically in the tumour and not the host immune cells would be efficacious for tumour therapy.
Department of Pathology, University of California, San Diego, La Jolla, CA, USA.
Carlos
C
Peinado
Xi
X
Kang
Chanae
C
Hardamon
Sumit
S
Arora
Stephen
S
Mah
Hui
H
Zhang
Jennifer
J
Ngolab
Jack D
JD
Bui
D000818:Animals; D045744:Cell Line, Tumor; D003546:Cysteine Endopeptidases; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D051550:I-kappa B Kinase / Q000235:genetics / Q000378:metabolism; D020672:I-kappa B Proteins / Q000235:genetics / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D007694:Killer Cells, Natural / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D015778:Minor Histocompatibility Antigens / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000235:genetics* / Q000378:metabolism; D055655:NK Cell Lectin-Like Receptor Subfamily K / Q000235:genetics* / Q000378:metabolism; D009369:Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics*; D012460:Sulfasalazine / Q000494:pharmacology; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism
D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D047908:Intracellular Signaling Peptides and Proteins; D015778:Minor Histocompatibility Antigens; D016328:NF-kappa B; D055655:NK Cell Lectin-Like Receptor Subfamily K; C000606205:Nfkbia protein, mouse; C114735:minor H antigen H60; D000072000:NF-KappaB Inhibitor alpha; D012460:Sulfasalazine; D044767:Ubiquitin-Protein Ligases; D051550:I-kappa B Kinase; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D003546:Cysteine Endopeptidases; C513261:Tnfaip3 protein, mouse