Carbazole and tetrahydro-carboline derivatives as dopamine D3 receptor antagonists with the multiple antipsychotic-like properties.

Dopamine D3 receptor (D3R) is implicated in multiple psychotic symptoms. Increasing the D3R selectivity over dopamine D2 receptor (D2R) would facilitate the antipsychotic treatments. Herein, novel carbazole and tetrahydro-carboline derivatives were reported as D3R selective ligands. Through a structure-based virtual screen, ZLG-25 (D3R Ki = 685 nmol/L; D2R Ki > 10,000 nmol/L) was identified as a novel D3R selective bitopic ligand with a carbazole scaffold. Scaffolds hopping led to the discovery of novel D3R-selective analogs with tetrahydro-ß-carboline or tetrahydro-γ-carboline core. Further functional studies showed that most derivatives acted as hD3R-selective antagonists. Several lead compounds could dose-dependently inhibit the MK-801-induced hyperactivity. Additional investigation revealed that 23j and 36b could decrease the apomorphine-induced climbing without cataleptic reaction. Furthermore, 36b demonstrated unusual antidepressant-like activity in the forced swimming tests and the tail suspension tests, and alleviated the MK-801-induced disruption of novel object recognition in mice. Additionally, preliminary studies confirmed the favorable PK/PD profiles, no weight gain and limited serum prolactin levels in mice. These results revealed that 36b provided potential opportunities to new antipsychotic drugs with the multiple antipsychotic-like properties.

Optimization of 4-arylthiophene-3-carboxylic acid derivatives as inhibitors of ANO1: Lead optimization studies toward their analgesic efficacy for inflammatory pain.

Current pain management is largely limited to opioids and non-steroidal anti-inflammatory drugs. Developing new analgesic drugs remains important to address the unmet medical needs of chronic pain patients. Calcium-activated chloride channel anoctamin-1 (ANO1) is a potential analgesic target. ANO1 is activated by noxious stimuli in peripheral sensory neurons and further induced neural depolarization. Downregulation of ANO1 reduced hyperalgesia and allodynia caused by inflammation and nerve injury. Here we developed a series of 4-arylthiophene-3-carboxylic acid derivatives for proof-of-concept studies of ANO1-targeted analgesia. These efforts led to the identification of the compound DFBTA, 4-(4-chlorophenyl)-2-(2,5-difluorobenzamido)thiophene-3-carboxylic acid, which displays dramatic ANO1 inhibition with IC50 of 24 nM. DFBTA displays very weak cytotoxicity, cardiotoxicity, and acute toxicity (HEK293 proliferation IC50 > 30 µM, hERG IC50 > 30 µM, mouse minimum lethal dosage, MLD>1000 mg/kg), as well as excellent pharmacokinetics properties with oral bioavailability >75% and little brain penetration (<1.5% brain/plasma). Finally, the analgesic efficacy of ANO1 inhibitor was evaluated in animal models. DFBTA shown comparable efficacy to clinical drugs in all inflammatory pain models induced by complete Freund's adjuvant, formalin, and capsaicin. These works provide a useful tool compound and promising results for ANO1-targenting analgesic development.

Discovery of novel ataxia telangiectasia mutated (ATM) kinase modulators: Computational simulation, biological evaluation and cancer combinational chemotherapy study.

Ataxia-telangiectasia mutated (ATM) kinase is a serine/threonine protein kinase and plays a key role in DNA double-strand breaks repair. Thus, ATM is considered a promising target for radiotherapy and chemotherapy sensitizing. Herein, we report the discovery of ATM agonist A22 and inhibitor A41 by computational methods and further biological evaluation. Among them, A22 exhibited low cytotoxicity in vitro and might serve as a useful tool for ATM research. Moreover, we firstly proved that ATM inhibitors could sensitize Irinotecan and Etoposide in a time-dependent manner on MCF-7 and SW480 cells, antagonism in a short period treatment while synergy at a long-term treatment and ATM agonist worked in an opposite way of ATM inhibitors. Further mechanism study demonstrated that the antagonism effect of ATM inhibitors with chemotherapeutic agents in a short period was resulting from inhibiting the p53/p21 axis to accelerate G1/S phase cell-cycle transition and promote cell survival. Additionally, A41 displayed antitumor effects combined with a chemotherapeutic drug in the SW480 xenograft model, indicating that A41 is a promising ATM inhibitor, which could increase the antitumor effect of chemotherapeutic drugs in vivo. All in all, these findings will guide the combination of ATM inhibitors with chemotherapeutic agents in further preclinical and clinical studies.

Design, synthesis and biological activities of benzo[d]imidazo[1,2-a]imidazole derivatives as TRPM2-specfic inhibitors.

Transient receptor potential melastatin 2 (TRPM2) channel is associated with ischemia/reperfusion injury, inflammation, cancer and neurodegenerative diseases. However, the lack of specific inhibitors impedes the development of TRPM2 targeted therapeutic agents. To develop a selective TRPM2 inhibitor, three-dimensional similarity-based screening strategy was employed using the energy-minimized conformation of non-selective TRPM2 inhibitor 2-APB as the query structure, which resulted in the discovery of a novel tricyclic TRPM2 inhibitor Z-4 with benzo[d]imidazo[1,2-a]imidazole skeleton. A series of Z-4 derivatives were subsequently synthesized and evaluated using calcium imaging and electrophysiology approaches. Among them, preferred compounds ZA10 and ZA18 inhibited the TRPM2 channel with micromolar half-maximal inhibitory concentration values and exhibited TRPM2 selectivity over the TRPM8 channel, TRPV1 channel, InsP3 receptor and Orai channel. The analysis of structure-activity relationship provides valuable insights for further development of selective TRPM2 inhibitors. Neuroprotection assay showed that ZA10 and ZA18 could effectively reduce the mortality of SH-SY5Y cells induced by H2O2. These findings enrich the structure types of existing TRPM2 inhibitors and might provide a new tool for the study of TRPM2 function in Reactive oxygen species (ROS) -related diseases.

The Discovery of Novel ACA Derivatives as Specific TRPM2 Inhibitors that Reduce Ischemic Injury Both In Vitro and In Vivo.

The transient receptor potential melastatin 2 (TRPM2) channel is associated with ischemia/reperfusion injury, inflammation, cancer, and neurodegenerative diseases. However, the limit of specific inhibitors impedes the development of TRPM2-targeted therapeutic agents. To discover more potent and selective TRPM2 inhibitors, 59 N-(p-amylcinnamoyl) anthranilic acid (ACA) derivatives were synthesized and evaluated using calcium imaging and electrophysiology approaches. Systematic structure-activity relationship studies resulted in some potent compounds inhibiting the TRPM2 channel with sub-micromolar half-maximal inhibitory concentration values. Among them, the preferred compound A23 exhibited TRPM2 selectivity over TRPM8 and TRPV1 channels as well as phospholipase A2 and showed neuroprotective activity in vitro. Following pharmacokinetic studies, A23 was further evaluated in a transient middle cerebral artery occlusion model in vivo, which significantly reduced cerebral infarction. These data indicate that A23 might serve as a useful tool for TRPM2-related research as well as a lead compound for the development of therapeutic agents for ischemic injury.