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Adenovirus E1A, not human papillomavirus E7, sensitizes tumor cells to lysis by macrophages through nitric oxide- and TNF-alpha-dependent mechanisms despite up-regulation of 70-kDa heat shock protein. J Immunol 2003 Apr 15;170(8):4119-26



Pubmed ID




Scopus ID

2-s2.0-0037446784   19 Citations


Expression of adenovirus (Ad) serotype 2 or 5 (Ad2/5) E1A or human papillomavirus (HPV)16 E7 reportedly sensitizes cells to lysis by macrophages. Macrophages possess several mechanisms to kill tumor cells including TNF-alpha, NO, reactive oxygen intermediates (ROI), and Fas ligand (FasL). E1A sensitizes cells to apoptosis by TNF-alpha, and macrophages kill E1A-expressing cells, in part through the elaboration of TNF-alpha. However, E1A also up-regulates the expression of 70-kDa heat shock protein, a protein that inhibits killing by TNF-alpha and NO, thereby protecting cells from lysis by macrophages. Unlike E1A, E7 does not sensitize cells to killing by TNF-alpha, and the effector mechanism(s) used by macrophages to kill E7-expressing cells remain undefined. The purpose of this study was to further define the capacity of and the effector mechanisms used by macrophages to kill tumor cells that express Ad5 E1A or HPV16 E7. We found that Ad5 E1A, but not HPV16 E7, sensitized tumor cells to lysis by macrophages. Using macrophages derived from mice unable to make TNF-alpha, NO, ROI, or FasL, we determined that macrophages used NO, and to a lesser extent TNF-alpha, but not FasL or ROI, to kill E1A-expressing cells. Through the use of S-nitroso-N-acetylpenicillamine, which releases NO upon exposure to an aqueous environment, E1A was shown to directly sensitize tumor cells to NO-induced death. E1A sensitized tumor cells to lysis by macrophages despite up-regulating the expression of 70-kDa heat shock protein. In summary, E1A, but not E7, sensitized tumor cells to lysis by macrophages. Macrophages killed E1A-expressing cells through NO- and TNF-alpha-dependent mechanisms.

Author List

Miura TA, Morris K, Ryan S, Cook JL, Routes JM


John M. Routes MD Chief, Professor in the Pediatrics department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

3T3 Cells
Adenovirus E1A Proteins
Adenoviruses, Human
Cell Line, Transformed
Cytotoxicity Tests, Immunologic
Fas Ligand Protein
HSP70 Heat-Shock Proteins
Macrophage Activation
Membrane Glycoproteins
Mice, Inbred C57BL
Nitric Oxide
Oncogene Proteins, Viral
Papillomavirus E7 Proteins
Sarcoma, Experimental
Tumor Cells, Cultured
Tumor Necrosis Factor-alpha
fas Receptor