Design, Synthesis, and Bioevaluation of Novel Reversibly Photoswitchable PI3K Inhibitors Based on Phenylazopyridine Derivatives toward Light-Controlled Cancer Treatment.

Photopharmacology is an emerging approach for achieving light-controlled drug activity. Herein, we design and synthesize a novel series of photoswitchable PI3K inhibitors by replacing a sulfonamide moiety with an azo group in a 4-methylquinazoline-based scaffold. Through structure-activity relationship studies, compound 6g is identified to be effectively switched between its trans- and cis-configuration under irradiation with proper wavelengths. Molecular docking studies show the cis-isomer of 6g is favorable to bind to the PI3K target, supporting compound 6g in the PSS365 (cis-isomer enriched) was more potent than that in the PSSdark (trans-isomer dominated) in PI3K enzymatic assay, cell antiproliferative assay, Western blotting analysis on PI3K downstream effectors, cell cycle analysis, colony formation assay, and wound-healing assay. Relative to the cis-isomer, the trans-isomer is more metabolically stable and shows good pharmacokinetic properties in mice. Moreover, compound 6g inhibits tumor growth in nude mice and a zebrafish HGC-27 xenograft model.

Discovery of Quinazoline-2,4(1H,3H)-dione Derivatives Containing a Piperizinone Moiety as Potent PARP-1/2 Inhibitors─Design, Synthesis, In Vivo Antitumor Activity, and X-ray Crystal Structure Analysis.

PARP-1/2 inhibitors have become an important therapeutic strategy for the treatment of HR-deficient tumors. However, discovery of new inhibitors with an improved and distinct pharmacological file still need enormous explorations. Herein, a series of novel highly potent PARP-1/2 inhibitors bearing an N-substituted piperazinone moiety were achieved. In particular, Cpd36 was identified as a distinct PARP inhibitor, showing remarkable enzymatic activity not only toward PARP-1 (IC50 = 0.94 nM) and PARP-2 (IC50 = 0.87 nM) but also toward PARP-7 (IC50 = 0.21 nM), as well as high selectivity over other PARP isoforms. Furthermore, Cpd36 was orally bioavailable and significantly repressed the tumor growth in both breast cancer and prostate cancer xenograft model. The crystal structures of Cpd36 within PARP-1 and PARP-2 together with the predicted binding mode within PARP-7 revealed its binding features and provided insightful information for further developing highly potent and selective PARP-1 and/or PARP-7 inhibitors.

Simulation of a micron resolution capillary liquid scintillation detector for 14 MeV fusion neutrons.

Aiming to improve the spatial resolution of a neutron imaging system (NIS) for 14 MeV fusion neutrons, an ideal micron resolution capillary detector filled with a high optical index liquid scintillator was simulated. A threshold for each capillary pixel and a threshold for each cluster were applied to suppress the gamma-induced background. In addition, by using a pattern recognition algorithm and an optimized Hough transform, the accuracy of determining the neutron impinging positions and the dynamic range of this detector were enhanced. For an ideal capillary array detector, the spatial resolution is expected as one capillary size of 20µm. The dynamic range of ∼1000 is reachable while the accuracy of neutron impinging position determination keeps better than 85%. The ionization quenching, light sharing and energy resolution of the detector were applied to the simulated data to understand the capillary array detector.

The effects of missense OPN3 mutations in melanocytic lesions on protein structure and light-sensitive function.

Opsin 3 (OPN3), a member of the light-sensitive, retinal-dependent opsin family, is widely expressed in a variety of human tissues and plays a multitude of light-dependent and light-independent roles. We recently identified five missense variants of OPN3, including p. I51T, p. V134A, p. V183I, p. M256I and p. C331Y, in human melanocytic tumours. However, it remains unclear how these OPN3 variants affect OPN3 protein structure and function. Herein, we conducted structural and functional studies of these variant proteins in OPN3 by molecular docking and molecular dynamics simulations. Moreover, we performed in vitro fluorescence calcium imaging to assess the functional properties of five single-nucleotide variant (SNV) proteins using a site-directed mutagenesis method. Notably, the p. I51T variant was not able to effectively dock with 11-cis-retinal. Additionally, in vitro, the p. I51T SNVs failed to induce any detectable changes in intracellular Ca2+ concentration at room temperature. Taken together, these results reveal that five SNVs in the OPN3 gene have deleterious effects on protein structure and function, suggesting that these mutations, especially the p. I51T variant, significantly disrupt the canonical function of the OPN3 protein. Our findings provide new insight into the role of OPN3 variants in the loss of protein function.