Tumors promote altered maturation and early apoptosis of monocyte-derived dendritic cells.
Tumors produce a number of immunosuppressive factors that block the maturation of CD34+ stem cells into dendritic cells (DC). We hypothesized that tumors might also interfere with the maturation and/or function of human monocyte-derived DC. In contrast to stem cells, we found that CD14+ cells responded to tumor culture supernatant (TSN) by increasing expression of APC surface markers, up-regulating nuclear translocation of RelB, and developing allostimulatory activity. Although displaying these characteristics of mature DC, TSN-exposed DC lacked the capacity to produce IL-12, did not acquire full allostimulatory activity, and rapidly underwent apoptosis. The effects of TSN appeared to be specific for maturing DC, and were not reversed by Abs against known DC regulatory factors including IL-10, vascular endothelial growth factor, TGF-beta, or PGE2. Supernatants collected from nonmalignant cell sources had no effect on DC maturation. The altered maturation and early apoptosis of monocyte-derived DC may represent another mechanism by which tumors evade immune detection.
Kiertscher
S M
SM
Division of Pulmonary Medicine, Comprehensive Cancer Center, University of California, Los Angeles, School of Medicine, Los Angeles, CA 90095, USA. skiertscher@mednet.ucla.edu
Luo
J
J
Dubinett
S M
SM
Roth
M D
MD
D017209:Apoptosis / Q000276:immunology*; D001692:Biological Transport / Q000276:immunology; D001943:Breast Neoplasms; D002292:Carcinoma, Renal Cell; D002454:Cell Differentiation / Q000276:immunology; D002467:Cell Nucleus / Q000378:metabolism; D002474:Cell-Free System / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D003713:Dendritic Cells / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D016130:Immunophenotyping; D018664:Interleukin-12 / Q000494:pharmacology; D008175:Lung Neoplasms; D008545:Melanoma; D009000:Monocytes / Q000166:cytology* / Q000276:immunology*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051841:Transcription Factor RelB; D014157:Transcription Factors / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000737:chemistry / Q000276:immunology*
D016207:Cytokines; D011518:Proto-Oncogene Proteins; C497593:RELB protein, human; D014157:Transcription Factors; D051841:Transcription Factor RelB; D018664:Interleukin-12