CHARACTERIZATION OF NEW RIPKs FAMILY MEMBERS: HIGHLIGHTS ON THE BIOLOGICAL ROLE OF RIPK2 AND RIPK4 IN CANCER

Receptor-Interacting Protein Kinases (RIPKs) are a seven-member family of Ser/Thr protein kinases involved in host defense, inflammatory phenomena as well as in cell death. To date their role in tumorigenesis is still unclear. Little scientific evidence explains the direct involvement of RIPK2 and RIPK4 in pathogenesis, especially in cancer. Several cell death regulation strategies have been studied in order to improve anticancer therapies and, among these, the study of the RIP kinase family is particularly interesting, which offers a therapeutic alternative in cases of resistance to apoptotic processes. It is known that RIPK2, through its CARD functional domain, is able to trigger the activation of NF-kB or the MAP kinase pathway, playing a fundamental role in the immune response and inflammation while RIPK4 appears to participate both physically and functionally in several TRAF-dependent pathways leading to the activation of NF-kB pathway. Methods: Western blot, RT-qPCR, Immunoprecipitation, Transfection. Results. Since both kinases are differentially expressed in different cancer types and the molecular mechanisms involved are poorly characterized, one of the main objectives of the project is to characterize the oncogenic role of these proteins by studying key molecular interactors and activated protein complexes. For this purpose, different cancer cell models exhibiting variable expression levels were chosen. Jurkat and Raji tumoral cell lines, in which RIPK2 is respectively poor and high expressed, as well as HL-60 and PANC-1 tumoral cell lines for RIPK4 investigation will be considered. To identify molecular players, MS/MS analysis coupled immunoprecipitation experiments were performed. Waiting for these results, molecular screening experiments have been started in order to identify molecules that modulate the expression of these kinases, that are structural scaffolds useful for the synthesis of new molecules. Conclusions. Further studies will be needed to better understand the biological activity of the investigated proteins and to understand the possible cross talk between different family members.