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Blood, 1 April 2008, Vol. 111, No. 7, pp. 3635-3643. Prepublished online as a Blood First Edition Paper on January 25, 2008; DOI 10.1182/blood-2007-11-123141.
IMMUNOBIOLOGY B7-H1 is a ubiquitous antiapoptotic receptor on cancer cells1 Department of Dermatology and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD B7-H1 is an immunoglobulin-like immune suppressive molecule broadly detectable on the majority of human and rodent cancers, and its functions have been attributed to delivering an inhibitory signal to its counter-receptor programmed death-1 (PD-1) on T cells. Here we report that B7-H1 on cancer cells receives a signal from PD-1 to rapidly induce resistance against T cell–mediated killing because crippling signaling capacity of B7-H1 but not PD-1 ablates this resistance. Importantly, loss of B7-H1 signaling is accompanied by increased susceptibility to immune-mediated tumoricidal activity. In addition to resistance against T-cell destruction, B7-H1+ cancer cells also become refractory to apoptosis induced by Fas ligation or the protein kinase inhibitor Staurosporine. Our study reveals a new mechanism by which cancer cells use a receptor on immune cells as a ligand to induce resistance to therapy.
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| Copyright © 2008 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||||