Aim 1. Synthesize and optimize potent and selective NEK2-PROTACs in vitro. The working hypothesis for
this Aim is that a PROTAC strategy combined with a NEK2 inhibitor might yield a very potent and selective NEK2 degradation. In this Aim, we will further design and synthesize the CRBN-PROTAC compounds to target the NEK2 protein. We will evaluate the NEK2-PROTACs for their in vitro potency and selectivity using biochemical and cell-based assays. We expect that the NEK2-PROTAC compounds, compared to INH154 itself, will exhibit much stronger potency and specificity to target NEK2 positive MM cells.
Aim 2: Characterize and optimize drug properties of NEK2-PROTACs in vivo. The working hypothesis for
this Aim is that the drug properties of NEK2-PROTACs are optimizable. We will perform absorption,
distribution, metabolism, and excretion (ADME) and drug metabolism and pharmacokinetic (DMPK) of the
optimized compounds. We will also evaluate toxicities of these NEK2-PROTACs using the 5TGM1-KaLwRij
MM mouse model, which recapitulates the human MM disease in an immune-competent environment. We
expect the NEK2-PROTAC compounds, compared to INH154 itself, will have drug properties with diminished cytotoxicity and better efficacy.
Aim 3. Determine the therapeutic effects of NEK2-PROTACs in myeloma. The working hypothesis is that
the NEK2-PROTACs specifically degrade NEK2 protein resulting in selective elimination of high-NEK2 MM
cells and restoration of sensitivity to ICB drug in drug-resistant MM cells. We will determine whether the NEK2-PROTACs can overcome drug resistance in a xenograft MM mouse model (Aim 3.1), can kill NEK2+ primary MM cells in vitro and in a newly developed patient-derived xenograft MM mouse model (Aim 3.2), and facilitates sensitivity to an ICB drug in the immune competent 5TGM1-KaLwRij mouse model (Aim 3.3). We will also investigate the underlying mechanisms by which NEK2 suppresses PD-L1 expression in MM cells (Aim 3.4). We expect that the NEK2-PROTACs will selectively target drug-resistant MM cells in which NEK2 is highly expressed and that combination therapy with the ICB drug (mPD-L1 Ab) will prevent MM relapse.

2021-04-23

2022-04-22