Design, synthesis and biological evaluation of small molecule fluorescent probes targeting EGFR for tumor detection and treatment.

The epidermal growth factor receptor (EGFR) is a tyrosine kinase receptor that plays a crucial role in cell differentiation and tumor progression, and its overexpression is closely associated with the development and metastasis of multiple cancers. The development of a fluorescent probe capable of targeting EGFR while simultaneously integrating diagnostic and therapeutic functions could have a profound impact on the treatment of related cancers. In this study, we developed a series of EGFR-targeting probes that consisted of an environment-sensitive 1,8-naphthalimide fluorophore, a linker unit and a targeting unit (gefitinib), using a coupling strategy. The synthesized probes were first evaluated for their spectroscopic properties and cytotoxicities against different cell lines, which were selected based on their intrinsic EGFR expression levels. Remarkably, among the probes tested, GP1 showed outstanding environmental sensitivity and exhibited a specific response to tumor cells that overexpress EGFR. Furthermore, the representative probe GP1 was evaluated for its EGFR-specific targeting ability in live-cell fluorescence imaging and in vivo xenograft imaging, as well as its in vivo anti-tumor activity. The results showed that the probe GP1 had excellent EGFR-specific targeting ability, exhibited competitive replacement behavior towards the EGFR inhibitor gefitinib, and demonstrated potent anti-tumor effects in a CT-26 tumor-bearing mouse model. Overall, as a turn-on EGFR targeting fluorescent ligand, GP1 holds immense promise as a valuable tool for tumor detection and treatment.

Novel dual-target µ­opioid and TRPV1 ligands as potential pharmacotherapeutics for pain management.

Currently, the development of effective analgesic drugs with few side effects remains a great challenge. Studies have suggested that multi-target drug treatments show high efficacy and reduced side effects compared to single-target drug therapies. In this work, we designed and synthesized two series of novel MOR/TRPV1 dual active ligands in which the phenylpiperidine group or the N-phenyl-N-(piperidin-4-yl) propionamide group as the MOR pharmacophore was fused to the benzylpiperazinyl urea-based TRPV1 pharmacophore. In particular, compound 5a exhibited promising dual pharmacological activity for MOR (EC50 = 53.7 nM) and TRPV1 (IC50 = 32.9 nM) in vitro. In formalin tests, compound 5a showed potent, dose-dependent in vivo analgesic activity in both the 1st and 2nd phases. Gratifyingly, compound 5a did not cause the side effects of hyperthermia and analgesic tolerance. Consistent with its in vitro activity, compound 5a also simultaneously agonized MOR and antagonized TRPV1 in vivo. Further studies on compound 5a showed acceptable pharmacokinetic properties and brain permeability. Furthermore, molecular docking studies showed that compound 5a tightly bound to the active pockets of hMOR and hTRPV1, respectively. Overall, this work shows the promise in discovering new analgesic treatments through the strategy of simultaneously targeting MOR and TRPV1 with a single molecule.

Rational design synthesis and evaluation of a novel near-infrared fluorescent probe for selective imaging of amyloid-ß aggregates in Alzheimer's disease.

Alzheimer's disease (AD) is a degenerative neurological disorder that remains incurable to date, seriously affecting the quality of life and health of those affected. One of the key neuropathological hallmarks of AD is the formation of amyloid-ß (Aß) plaques. Near-infrared (NIR) probes that possess a large Stokes shift show great potential for imaging of Aß plaques in vivo and in vitro. Herein, we proposed a rational strategy for design and synthesis of a series of NIR fluorescent probes that incorporate a tricarbonitrile group as a strong electron-withdrawing group (EWG) to enable NIR emission and large Stokes shift for optimal imaging of Aß plaques. The probe TCM-UM exhibited remarkable in vitro performance, including strong NIR emission (λem = 670 nm), large Stokes shift (120-245 nm), and its affinity for Aß42 aggregates (Kd = 43.78 ± 4.09 nM) was superior to the commercially available probe Thioflavin T (ThT, Kd = 896.04 ± 33.43 nM). Further, TCM-UM was selected for imaging Aß plaques in brain tissue slices and APP/PS1 transgenic (AD) mice, the results indicated that TCM-UM had an excellent ability to penetrate the blood-brain barrier (BBB) compared with ThT, and it could effectively distinguish wild-type (Wt) mice and APP/PS1 transgenic (AD) mice.

Discovery of (S)-N-(3-isopropylphenyl)-2-(5-phenylthiazol-2-yl)pyrrolidine-1-carboxamide as potent and brain-penetrant TRPV1 antagonist.

Transient receptor potential vanilloid 1 (TRPV1) antagonists can inhibit the transmission of nociceptive signals from the peripheral to the central nervous system (CNS), providing a new strategy for pain relief. In this work, in order to develop potent, CNS-penetrant, and orally available TRPV1 antagonists, three series of novel molecules based on the key pharmacophore structures of classic TRPV1 ligands SB-705498 and MDR-652 were designed and synthesized. Through systematic in vitro and in vivo bioassays, (S)-N-(3-isopropylphenyl)-2-(5-phenylthiazol-2-yl)pyrrolidine-1-carboxamide (7q) was finally identified, which had enhanced TRPV1 antagonistic activity (IC50 (capsaicin) = 2.66 nM), excellent CNS penetration (brain/plasma ratio = 1.66), favorable mode-selectivity, good bioavailability, and no side effects of hyperthermia. Molecular docking and dynamics studies indicated that the high binding affinity of compound 7q to TRPV1 was related to multiple interactions, which resulted in significant conformational changes of TRPV1. Overall, our findings have led to a potent, mode-selective, and CNS-penetrant TRPV1 antagonist as a valuable lead for development of novel TRPV1 antagonists.