title: Hypoxia Studies with Pimonidazolein vivo.
abstract: Therapy-induced hypoxia drives changes in the tumor microenvironment that contribute to the poor response to therapy. Hypoxia is capable of driving the expression and/or activation of specific signaling cascades (e.g., c-Met, Axl, CTGF), the recruitment of tumor promoting immune cells, and the induction of cell survival pathways including autophagy (Phanet al., 2013; Huet al., 2012; Yeet al., 2010). We have recently shown that anti-VEGF therapy-induced hypoxia can result in changes in the extracellular matrix that contribute to the aggressiveness of tumors post therapy (Aguileraet al., 2014). Importantly, therapies that induce hypoxia do not always increase epithelial plasticity and tumor aggressiveness (Ostapoffet al., 2013; Ceniket al., 2013). We have used pimonidazole to evaluate hypoxia in tumors and herein provide a detailed protocol for this useful tool to interrogate the levels of hypoxiain vivo. The utility of the Hypoxyprobe™(pimonidazole hydrochloride) immunohistochemical analysis approach allows for the assessment of hypoxia in different tissues as well as cell types. Pimonidazole is a 2-nitroimidazole that is reductively activated specifically in hypoxic cells and forms stable adducts with thiol groups in proteins, peptides, and amino acids (Ceniket al., 2013; Arnoldet al., 2010; Raleigh and Koch, 1990; Raleighet al., 1998). Furthermore, the amount of pimonidazole that is detected is directly proportional to the level of hypoxia within tumors.
authors.affiliation: Department of Surgery, Hamon Center for Therapeutic Oncology Research, Dallas, USA.
authors.forename: Kristina Y
authors.initials: KY
authors.lastname: Aguilera
authors.affiliation: Department of Surgery, Hamon Center for Therapeutic Oncology Research, Dallas, USA; Department of Pharmacology, UT Southwestern Medical Center, Dallas, USA.
authors.forename: Rolf A
authors.initials: RA
authors.lastname: Brekken