Cancer is the leading cause of death worldwide and its numbers are projected to rise further, resulting in an estimated 12 million deaths in 2030. Current standard therapies, such as chemotherapy and radiation therapy, have yielded significant benefit in a few cancers, but long-term survival gains are uncommon, especially for advanced disease. Thus, these treatments are insufficient by themselves to combat the escalating trend in cancer mortality. Immune therapy offers an interesting approach to cancer treatment and adoptive cell transfer (ACT) therapy, in particular, has demonstrated great promise in ongoing clinical trials. ACT utilizes large numbers of autologous tumor-associated antigen (TAA)-specific T cells for patient treatment and has yielded objective response rates of ~50% in metastatic melanoma (Dudley et al., 2005;Rosenberg et al., 2008). ACT therapy in the clinic, however, has been limited for solid tumors and predominantly focused on the treatment of melanoma. This is partly due to the identification of many melanoma-associated antigens and the development of a therapeutic MART-1-specific T cell receptor (TCR) (Hughes et al., 2005;Novellino et al., 2005). Conversely, for other cancer types, there is a dearth of known TAAs and far fewer matching TCRs that are viable for clinical investigation. Thus, to expand the scope of ACT therapy, a large-scale effort to identify new therapeutic targets (i.e. TAAs) and reagents (i.e. complementary TCRs) for immune therapy against ovarian cancer will be undertaken. Utilizing a proteomics approach, major histocompatibility complex (MHC) class I- presented peptides will be extracted and sequenced from HLA-A2+ ovarian cancer cell lines to generate a comprehensive library of putative tumor-associated antigens. Within this library, the immunogenic antigens will be identified through the use of tumor-infiltrating lymphocytes (TILs) from ovarian cancer patient samples. Then, in turn, the immunogenic antigens will be used to physically retrieve antigen-specific T cells from TIL samples and TCR genes from individual cells will be cloned to generate a library of tumor-reactive T cell receptor genes. This task will require the development and employment of a new integrated microfluidics platform for single cell capture, whole-genome amplification, and sequential TCR-specific PCR. Once TAA and TCR libraries are both assembled, library-against-library screens will be performed to pair functional TCR genes and identify their complementary TAAs. Successfully matched TAAs and TCRs will subsequently be characterized to acquire information that will help in stratifying TAA-TCR pairs for potential therapeutic use. Ovarian cancer is the leading cause of death due to gynecological cancer in the Western world and, thus, stands to benefit greatly from new therapeutic interventions. This general strategy can be applied to other cancers in the future.
Adoptive T cell transfer involves the use of tumor-targeting T cells for cancer therapy and has demonstrated real promise in clinical trials in patients with advanced melanoma.
We aim to expand this treatment to include patients with ovarian cancer by identifying relevant tumor antigens and corresponding T cell receptors. Tumor antigens serve as potential targets for cancer immune therapy, while the T cell receptors form the basis of the actual treatment.
