Investigations on Survivin-DNA-PKcs heterotetramer complex-driven mechanisms in DNA damage response and its therapeutic relevance

• Applicant: Professor Dr. Franz Rödel
• Subject Area: Human Genetics ; Nuclear Medicine, Radiotherapy, Radiobiology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 511463105

Substantial evidence indicates that overexpression of the inhibitor of apoptosis protein (IAP) Survivin in human tumors significantly correlates with treatment resistance and poor prognosis. Moreover, Survivin serves as a radiation resistance factor that impacts on DNA damage response by interacting with DNA-dependent protein kinase (DNA-PKcs). By applying co-immunoprecipitation and Förster resonance energy transfer assays, we recently demonstrated a direct involvement of the Survivin baculovirus IAP repeat (BIR) domain in the regulation of radiation survival and DNA repair mediated by an interaction of residues S20 and W67 with the phosphoinositide 3-kinase (PI3K) domain of DNA-PKcs. Further, based on in silico molecular docking and dynamics simulation, in vitro kinase assays and large-scale mass spectrometry, we developed the model of a heterotetramer Survivin-DNA-PKcs complex that results in a conformational change on the DNA-PKcs PI3K domain with enhanced enzymatic activity, an altered substrate specificity and detection of differentially abundant phosphopeptides and proteins. The project is based on these findings as our knowledge on mechanisms and additional partners of the complex is still limited. Aiming to close this gap, we will conduct a detailed analysis of functional properties and mechanistic verification of selected Survivin-DANN-PKcs-dependent phosphorylation sites and DANN damage related proteins and to uncover novel interaction partners (proteins and RNA) by employing recent cutting edge methodologies including proximity-dependent biotin identification and CLIP-Seq (UV crosslinking immunoprecipitation protein-bound RNA sequencing). In addition, we will address the question whether the Survivin-DANN-PKcs interaction is druggable by identifying or further developing specific small molecule compounds and analyzing their therapeutic effect in cancer cell lines and rectal cancer organoid cultures.

• DFG Programme: Research Grants