Achim Temme Group
Our group focuses on the identification and characterization of tumor-associated antigens in neoplasms of the brain and the development of new treatment strategies including gene therapy and immunotherapy.
(I) Survivin, originally classified as inhibitor of apoptosis protein (IAP), is overexpressed in most tumors when compared to normal tissue. It has attracted special interest, since interfering with its function using knock out-, RNAi or dominant-negative Survivin mutants is not compatible with life. Recent analysis of the cellular function revealed that Survivin represents a chromosomal passenger protein which is essential for the spindle assembly checkpoint (SAC) and proper execution of cytokinesis. Ectopic expression of dominant-negative Survivin mutants and knock down of Survivin in vitro resulted in severe mitotic defects accompanied by an caspase-independent cell death. Targeting Survivin in glioma xenografts by siRNAs demonstrated profound anti-tumoral effects and increased survival time.
(II) Natural killer cells (NK) are able to recognize and kill tumor cells with loss of HLA class I expression and concomitant decrease of HLA-E on their surface. However, some tumors still express HLA class I, and NK cell reactivity against HLA I-negative solid tumors can be blocked by inhibitory non classical HLA or by the lack of activating ligands on the surface of the tumor cells. Our group aims at establishing a NK cell-based immunotherapy using novel chimeric antigen receptors (CAR) consisting of single chain antibody fragment targeting surface tumor-antigens and the DNAX activation protein of 12kDa (DAP12). NK cells engrafted with these CARs confers selective cytotoxicity against antigen-positive target cells expressing HLA class I molecules and delays tumor growth in NMRInu/nu mice and also increases mean survival times.
Future Projects and Goals
- To elucidate the function of Survivin in the SAC
- To understand the interconnection between Survivin loss of function and gain of function phenotypes and cell cycle checkpoints/genomic instability
- To establish a siRNA-carrier system using single chain antibody derivatives for in vivo targeting EGFRvIII- and PSCA-positive tumors
- To develop advanced NK cell receptors for immunotherapy of cancer
Methodological and Technical Expertise
- design and recombinant expression of proteins in prokaryotic and eukaryotic systems
- vector design and retro/lentiviral gene transfer in primary cells (i.e. hematopoetic stem cells, NK cells, T cells)
- RNAi techniques (shRNA/siRNA) in vitro and in vivo
- cell culture methods (permanent/ primary cell lines, migration assays, clonogenic survival, sphere assays, etc.)
- imaging methods (time lapse video, confocal laser scan microscopy)
- protein biochemistry (i.e. ELISA, G-LISA, fluorescence polarization, IP, WB)