Kellner, M.; Hoermann, J.; Fackler, S.; Yuanyu, H.; Lin, L.; Ilik, I.; Aktas, T.; Feederle, R.; Hauck, S. M.; Gires, O.; Gaertner, K.; Lietao, L.; Zeidler, R.

The membrane composition of extracellular vesicles (EVs) largely reflects that of the plasma membrane of the cell of origin. We therefore hypothesized that EVs are a source for the detection of hitherto unknown tumor-associated druggable target molecules. For this, we used EVs derived from cancer cell lines for an immunization of a rat. From this immunization, we obtained a monoclonal antibody specific for SRRM2, a protein involved in splicing a major component of nuclear speckles. Here, we used this antibody to demonstrate that SRRM2 is exposed at the surface of most cancer cell lines from various entities and, even more important, on cancer cells in vivo. Moreover, we demonstrate that SRRM2-specific CAR-T cells are killing SRRM2-positive cancer cells effectively. Collectively, we identified SRRM2 as a promising new target molecule exposed on the cancer cell surface and show that our SRRM2-specific antibody can be used as a basis for the development of new targeted cancer therapies.