It is my long-term career goal to become a clinician-scientist in the field of head and neck cancer. Despite medical advances in other areas, treatment modalities for head and neck cancer have not changed over the past 30 years. Surgery, radiation, and chemotherapy are still the mainstays of treatment, and five-year survival rates for many tumors remain poor. New therapies are needed. Recent studies indicate that most oropharyngeal squamous cell carcinomas have undergone transformation by human papilloma virus (HPV). Two early transforming HPV proteins, E6 and E7, are expressed in these tumors and they provide attractive targets for cancer immunotherapy. Listeria monocytogenes-based vaccines have been developed that cause regression of HPV-associated tumors in animal models. In this proposal, we hope to develop new strategies that will make this type of therapy more effective and clinically applicable.
In Specific Aim #1, we will test a unique strategy that targets both transforming proteins expressed in HPV-associated tumors. Heretofore, experiments and clinical trials have only targeted either E6 or E7. Several different live recombinant vaccines, including Listeria and Vaccinia constructs, will be used in order to determine which combination is the most efficacious.
In Specific Aim #2, a novel Listeria construct will be engineered. This construct will include the Listeria protein ActA fused to the transforming proteins. The rationale behind creating this vaccine is the fact that ActA contains several PEST (P, proline; E, glutamic acid; S, serine; T, threonine) regions within its amino acid sequence. PEST regions have recently been shown to be critical for the efficacy of the Listeria constructs.
In Specific Aim #3, we will develop transgenic mice that will express E6 and E7 under the control of the thyroglobulin promoter. These mice will spontaneously produce HPV-transformed thyroid tumors. Using this model, the vaccines targeting HPV-associated tumors will be tested in mice with head and neck tumors that may be tolerant to the transforming proteins. This model mimics the situation that is seen in human head and neck cancer patients. In order to achieve my goal of treating these patients with immunotherapy, I am applying for a period of mentored research in Dr. Yvonne Paterson's laboratory.
