Targeted delivery of a PROTAC induced PDEδ degrader by a biomimetic drug delivery system for enhanced cytotoxicity against pancreatic cancer cells.

Pancreatic carcinoma (PC) has one of the highest mortality-to-incidence ratios of any solid tumor worldwide. Although KRAS mutation is commonly found in 95% of PCs, directly targeting KRAS remains to be a highly challenging task because of its lacking catalytic pockets where molecule inhibitors can bind with. Proteolysis-targeting chimeric (PROTAC) represents an effective approach for specific degradation of disease-causing proteins by hijacking the endogenous ubiquitin-proteasome system (UPS). Previously, we designed a first-in-class PROTAC induced PDEδ degrader (PIPD), which demonstrated improved anti-tumor efficacy against KRAS mutant malignancies. However, translating cellular degradative effects from bench to beside remains a highly challenging task because of PROTAC's poor penetration efficiency across target cytomembranes and non-targeting delivery induced undesired "off target" side-effects. Herein, a smart nano-drug delivery system (CM8988-PIPD) was successfully constructed by biomimetic strategy for targeted delivery of PIPD. The biomimetic nanoparticle showed well-defined regular spherical structure with an average particle size of approximately 124.8 nm. Cancer cytomembrane camouflage endows CM8988-PIPD with excellent in vivo serum stability, controlled drug release profile, favorable biocompatibility & immunocompatibility, and prominent targeting ability to homologous PC cells. Owing to these advantages, the smart DDS significantly enhanced PDEδ degrading efficacy, resulting in induced cellular apoptosis (more than 50% for both PC cells) and suppressed cell proliferation via the inhibition of RAS signaling. In vitro studies illustrated that CM8988-PIPD hold great potential for the treatment of PC, which merits further investigation in both pre-clinical and clinical investigations in the future.

Development of a compact coaxial cusped periodic permanent magnet focusing system.

To achieve the application of a periodic permanent magnet in high power microwave, a compact coaxial cusped periodic permanent magnet (CPPM) focusing system is constructed. The system consists of permanent magnets with different magnetization directions and soft magnets. Taking the required magnetic field performance and the effect of demagnetization into account, NdFeB and FeCoV are selected as the permanent and soft magnet materials. After the system is constructed, the magnetic field is measured. The results show that the guiding magnetic field strength and period of the CPPM are about 0.29 T and 26 mm, respectively, and the magnetic field distribution of measurement shows good agreement with the simulation results. However, there are some differences between the measurement and simulation results, and the differences are compared and analyzed here.