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Ames, IA, United States

Prendergast G.C.,Lankenau Institute for Medical Research | Metz R.,New Link Genetics Corporation
OncoImmunology | Year: 2012

Aging entails the accumulation of neoantigens comprised of aggregated, oxidized, mutated and misfolded biomolecules, including advanced-glycation end projects (AGEs). There is evidence that the immune system can recognize and clear cells fouled by these molecular debris, which contribute to the emergence of cancer and other major age-associated diseases such as atherogenic and neurodegenerative disorders. However, this process may become increasingly inefficient with aging, perhaps in part because of an insufficiency of adjuvant signals normally associated with infection that can program productive inflammatory states and properly orient the immune system toward regenerative healing. Here we propose conceptual foundations for exploring a small set of infection-associated molecules as potential immune adjuvants to reprogram non-productive inflammatory states in aging tissues, and to improve the clearance of cellular pathologies that engender age-associated disease. The proposed adjuvant classes include a subset of d-amino acids used by bacteria to disrupt biofilms; nucleoside derivatives of N6-methyladenine, which functions at the core of bacterial dam restriction systems; and derivatives of the galactosyl trisaccharide α-Gal, which invokes the hyperacute response in primates. These foreign amino acids, nucleosides and sugar molecules are generally rare or absent in humans, except in association with infections by bacteria, protists or nematodes. A rationale for exploration of these candidate adjuvant principles and their chemical derivatives is discussed in terms of their use in generalized strategies to improve the prevention or treatment of cancer and other age-associated diseases, as negative modifiers of aging. © 2012 Landes Bioscience.

Muller A.J.,Lankenau Institute for Medical Research | Muller A.J.,Thomas Jefferson University | Duhadaway J.B.,Lankenau Institute for Medical Research | Jaller D.,Lankenau Institute for Medical Research | And 4 more authors.
Cancer Research | Year: 2010

Efforts to improve cancer care in the developing world will benefit from the identification of simple, inexpensive, and broadly applicable medical modalities based on emergent innovations in treatment, such as targeting mechanisms of tumoral immune tolerance. In this report, we offer preclinical evidence that the low-cost, anti-inflammatory agent ethyl pyruvate elicits a potent immune-based antitumor response through inhibition of indoleamine 2,3-dioxygenase (IDO), a key tolerogenic enzyme for many human tumors. Consistent with its reported ability to interfere with NF-κB function, ethyl pyruvate blocks IDO induction both in vitro and in vivo. Antitumor activity was achieved in mice with a noncytotoxic dosing regimen of ethyl pyruvate shown previously to protect against lethality from sepsis. Similar outcomes were obtained with the functional ethyl pyruvate analogue 2-acetamidoacrylate. Ethyl pyruvate was ineffective at suppressing tumor outgrowth in both athymic and Ido1-deficient mice, providing in vivo corroboration of the importance of T-cell-dependent immunity and IDO targeting for ethyl pyruvate to achieve antitumor efficacy. Although ethyl pyruvate has undergone early-phase clinical testing, this was done without consideration of its possible applicability to cancer. Our findings that IDO is effectively blocked by ethyl pyruvate treatment deepen emerging links between IDO and inflammatory processes. Further, these findings rationalize oncologic applications for this agent by providing a compelling basis to reposition ethyl pyruvate as a low-cost immunochemotherapy for clinical evaluation in cancer patients. ©2010 AACR.

Prendergast G.C.,Lankenau Institute for Medical Research | Prendergast G.C.,Thomas Jefferson University | Metz R.,New Link Genetics Corporation | Muller A.J.,Lankenau Institute for Medical Research | And 4 more authors.
Frontiers in Immunology | Year: 2014

IDO2 is a relative of IDO1 implicated in tryptophan catabolism and immune modulation but its specific contributions to normal physiology and pathophysiology are not known. Evolutionary genetic studies suggest that IDO2 has a unique function ancestral to IDO1. In mice, IDO2 gene deletion does not appreciably affect embryonic development or hematopoiesis, but it leads to defects in allergic or autoimmune responses and in the ability of IDO1 to influence the generation of T regulatory cells. Gene expression studies indicate that IDO2 is a basally and more narrowly expressed gene than IDO1 and that IDO2 is uniquely regulated by AhR, which serves as a physiological receptor for the tryptophan catabolite kynurenine. In the established KRN transgenic mouse model of rheumatoid arthritis, where IDO1 gene deletion has no effect, IDO2 deletion selectively blunts responses to autoantigen but has no effect on responses to neoantigen challenge. In human populations, natural variations in IDO2 gene sequence that attenuate enzymatic activity have been reported to influence brain cancer control and adaptive immune responses to the IDO2 protein itself, consistent with the concept that IDO2 is involved in shaping immune tolerance in human beings. Biochemical and pharmacological studies provide further evidence of differences in IDO2 enzymology and function relative to IDO1. We suggest that IDO2 may act in a distinct manner from IDO1 as a set-point for tolerance to "altered-self" antigens along the self-non-self continuum where immune challenges from cancer and autoimmunity may arise.

Prendergast G.C.,Lankenau Institute for Medical Research | Prendergast G.C.,Thomas Jefferson University | Chang M.Y.,Lankenau Institute for Medical Research | Mandik-Nayak L.,Lankenau Institute for Medical Research | And 3 more authors.
Current Medicinal Chemistry | Year: 2011

Chronic inflammation underlies the basis for development and progression of cancers and a variety of other disorders, but what specifically defines its pathogenic nature remains largely undefined. Recent genetic and pharmacological studies in the mouse suggest that the immune modulatory enzyme indoleamine 2,3-dioxygenase (IDO), identified as an important mediator of immune escape in cancer, can also contribute to the development of pathology in the context of chronic inflammatory models of arthritis and allergic airway disease. IDO-deficient mice do not display spontaneous disorders of classical inflammation and small molecule inhibitors of IDO do not elicit generalized inflammatory reactions. Rather, in the context of a classical model of skin cancer that is promoted by chronic inflammation, or in models of inflammation-associated arthritis and allergic airway disease, IDO impairment can alleviate disease severity. Here we offer a survey of preclinical literature suggesting that IDO functions as a modifier of inflammatory states rather than simply as a suppressor of immune function. We propose that IDO induction in a chronically inflamed tissue may shape the inflammatory state to support, or in some cases retard, pathogenesis and disease severity. © 2011 Bentham Science Publishers Ltd.

Prendergast G.C.,Lankenau Institute for Medical Research LIMR | Prendergast G.C.,Thomas Jefferson University | Smith C.,Lankenau Institute for Medical Research LIMR | Thomas S.,Lankenau Institute for Medical Research LIMR | And 5 more authors.
Cancer Immunology, Immunotherapy | Year: 2014

Genetic and pharmacological studies of indoleamine 2,3-dioxygenase (IDO) have established this tryptophan catabolic enzyme as a central driver of malignant development and progression. IDO acts in tumor, stromal and immune cells to support pathogenic inflammatory processes that engender immune tolerance to tumor antigens. The multifaceted effects of IDO activation in cancer include the suppression of T and NK cells, the generation and activation of T regulatory cells and myeloid-derived suppressor cells, and the promotion of tumor angiogenesis. Mechanistic investigations have defined the aryl hydrocarbon receptor, the master metabolic regulator mTORC1 and the stress kinase Gcn2 as key effector signaling elements for IDO, which also exerts a non-catalytic role in TGF-β signaling. Small-molecule inhibitors of IDO exhibit anticancer activity and cooperate with immunotherapy, radiotherapy or chemotherapy to trigger rapid regression of aggressive tumors otherwise resistant to treatment. Notably, the dramatic antitumor activity of certain targeted therapeutics such as imatinib (Gleevec) in gastrointestinal stromal tumors has been traced in part to IDO downregulation. Further, antitumor responses to immune checkpoint inhibitors can be heightened safely by a clinical lead inhibitor of the IDO pathway that relieves IDO-mediated suppression of mTORC1 in T cells. In this personal perspective on IDO as a nodal mediator of pathogenic inflammation and immune escape in cancer, we provide a conceptual foundation for the clinical development of IDO inhibitors as a novel class of immunomodulators with broad application in the treatment of advanced human cancer. © 2014 Springer-Verlag.

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