Metastasis, or the spread of cancer cells from a primary tumor to distal tissue sites, is responsible for 90% of cancer-related deaths. Metastasis is a step-by-step process, with the major steps being initiation, invasion, migration, seeding, and colonization. Certain kinase families have been extensively studied as regulators of cell motility/invasion and epithelial-mesenchymal transition (EMT). Our preliminary data revealed members of the NEver-in-mitosis-related Kinase family (NEK5, NEK1 and NEK9) involved in the progression to the EMT phenotype. Previous studies demonstrate NEK9 and NEK1 are upstream regulators of PLK expression, but NEK5 remains uncharacterized. The use of kinase inhibitors to dissect and validate targetable nodes within cancer signaling pathways has revolutionized oncology drug discovery. Among the most interesting understudied IDG kinases is NEK5, a kinase linked to the critical biological process of epithelial to mesenchymal transition (EMT). Our preliminary evidence demonstrates that NEK5 is involved in pathways of significant pathological importance in difficult to treat breast cancer subtypes. There is an immediate need for potent, selective, and cell active NEK5 inhibitors that can be used to define the roles of NEK5 in EMT and evaluate the therapeutic potential of NEK5 inhibitors in relevant models of human disease. Here we propose a medicinal chemistry approach to optimize a promising inhibitor scaffold that we have identified and that has been declared an IDG tool molecule.
In Aim 1 we will synthesize new analogues of the IDG tool in order to optimize cellular activity and selectivity. We will optimize cellular potency using an IDG resource assay: the NEK5 nanoBRET in cell target engagement assay. We will optimize selectivity as judged by broad kinome profile of our best molecules. The deliverable from Aim 1 will be a potent, cell active, narrow spectrum NEK5 inhibitor. These results will pave the way for further work to optimize this NEK5 scaffold into compounds that can be tested in vivo and in the clinic.
In Aim 2 we will focus on delineating the biological role for NEK5 using triple negative breast cancer cell lines and patient derived xenograft model systems. To accomplish our goals, we have taken advantage of IDG published resources, and assembled a collaborative, multidisciplinary team with experience in kinase inhibitor optimization, cell biology, and tumor biology. Successful completion of this project will deliver a high quality NEK5 inhibitor, details on the roles NEK5 plays in the EMT, metastasis and tumorigenesis, and preliminary validation of NEK5 as a promising oncology drug discovery target for aggressive, hard to treat breast cancer subtypes. Results from experiments here may pave the way to new drugs for cancer treatment that target the understudied kinase NEK5. Free distribution of the NEK5 tool molecules will allow the community to determine other roles this IDG understudied kinase plays in signaling cascades in health and disease.
Metastatic cancer remains a formidable disease, with limited therapeutic options, and contributes to dramatically worse prognoses. While numerous cellular targets have been investigated in metastasis, the development of novel therapeutic compounds targeting cellular signaling through inhibition of specific kinases has been the primary focus both from a basic and translational research aspect. A significant portion of the human kinome remains uncharacterized and/or unrecognized particularly with regards to cancer progression. The experiments proposed in this grant would characterize the regulatory of an under-characterized kinase, NEK5, in promoting an invasive, motile cellular phenotype and initiation of metastatic disease.