DESIGN AND DEVELOPMENT OF AN I-BOOST VACCINE AGAINST TIMP1 IN COLORECTAL CANCER

Colorectal cancer (CRC) is the third most common cancer and it is the second most lethal one worldwide. The current treatments of CRCs are based on surgery, radiotherapy, chemotherapy, and immunotherapy. However, the management by means of the first three mentioned therapies can reduce the quality of life of the patients, while immunotherapy has an unsatisfactory response in mismatch repair proficient (pMMR) low microsatellite instability (MSI-L) tumors, which correspond to almost 95% of all metastatic CRC (mCRC) cases. Therefore, the prognosis for patients with metastatic CRC remains poor and the development of more effective treatments for this disease is an unmet need. Anti-angiogenic therapy proved to be effective in mCRC, but only contributed to modest improvement of patient survival. In this regard, tissue inhibitor metalloproteinase - 1 (TIMP-1) appears to be an interesting target for a new therapeutic strategy. TIMP-1 is a soluble protein found to be overexpressed in CRC and in the tumor vasculature. It has been associated with metastatic CRC and its high expression is negatively correlated with overall survival. This information gives rise to the idea that, by targeting TIMP-1, it may be possible to act both at the tumor cell and tumor vascular level, which could result in higher efficacy in the treatment of mCRC. Hence, the aim of this project was the development of a vaccine against the self-antigen TIMP-1 using the i-Boost technology. This strategy entails the formation of conjugated proteins (foreign sequences conjugated to TIMP-1) to induce an immune response against the self-antigen. Five different conjugated proteins were produced (CDP-TIMP1, CDP2.1-TIMP1, CDP2.2-TIMP1, CDP2.3-TIMP1 and TRXtr-TIMP1) and the best-performing protein in terms of purification yield, CDP-TIMP1, was selected to produce the vaccine that will be tested in a colorectal cancer mouse model. To further understand the role of this target, the effect of TIMP-1 inhibition on cell migration and viability were tested in vitro on SVEC (endothelial murine cell line) and CT26 (colorectal cancer murine cell line) cell lines. While the effects of anti-TIMP antibodies on cell migration were inconclusive, we observed an inhibition on viability in both the cell lines after the treatment with the antibodies. This data sustained the hypothesis that the targeting of this soluble protein can result in a double-effect therapy.