Targeting HPV E6-Dependent Hypoxia-Induced NF-kappa B in Cervical Cancer

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DESCRIPTION (provided by applicant): PROJECT ABSTRACT Cervical cancer is the leading cause of cancer-specific mortality amongst women worldwide and the human papilloma virus (HPV) plays a pathophysiologic role in cervical carcinogenesis in over 95% of cases. For over half a century, it has become increasingly established that intratumoral hypoxia is associated with an aggressive clinical phenotype, manifested by resistance to radiation and chemotherapy, a high risk of recurrence and metastasis, and shortened overall survival. The mechanistic underpinnings that account for these adverse clinical sequelae of hypoxia have not been elucidated. We recently identified a biochemical link between HPV infection and hypoxia in cervical cancer (Cancer Cell, 14:394, 2008). Specifically, we found that the HPV-encoded E6 protein mediates prolonged activation of the NF kappa B (NF-:B) signaling pathway under hypoxic conditions. As oxygen becomes a limiting substrate, E6 effectively targets CYLD, a negative regulator of the NF-:B pathway, for proteasome-mediated degradation, and thereby allows for unrestricted NF-:B activation. Through its transcriptional activity, NF-:B drives proliferation, survival, neo-angiogenesis, invasion and metastasis. Thus, we postulate that the poor clinical outcomes associated with hypoxia can in large part be attributed to E6-mediated, hypoxia-induced NF- :B activation. In pursuit of our hypothesis, we propose three aims in which we will be: 1) elucidating some of the key remaining biochemical and molecular cues that drive the E6-CYLD interaction (Specific Aim 1), 2) examining the relative effects of hypoxia-induced versus constitutive NF-:B activation on cervical tumorigenesis and metastasis development in murine xenografts models (Specific Aim 2), and 3) prospectively studying the relationship between hypoxia and NF-:B activation and CYLD expression in tumors of cervical cancer patients (Specific Aim 3). We have assembled a team of physician-scientists with diverse skill sets from various disciplines, including medical oncology, gynecologic oncology, and gynecologic pathology to further our molecular understanding of the hypoxic phenotype. Accomplishments from this proposal represent a necessary prelude to translate our work to early phase clinical trials aimed at targeting hypoxia-induced NF-:B activation, which can take advantage of the potentially high therapeutic index afforded by HPV positivity.