Design and Evaluation of 3-Phenyloxetane Derivative Agonists of the Glucagon-Like Peptide-1 Receptor.

Various small molecule GLP1R agonists have been developed and tested for treating type 2 diabetes (T2DM) and obesity. However, many of these new compounds have drawbacks, such as potential hERG inhibition, lower activity compared to natural GLP-1, limited oral bioavailability in cynomolgus monkeys, and short duration of action. Recently, a new category of 3-phenyloxetane derivative GLP1R agonists with enhanced hERG inhibition has been discovered. Using an AIDD/CADD method, compound 14 (DD202-114) was identified as a potent and selective GLP1R agonist, which was chosen as a preclinical candidate (PCC). Compound 14 demonstrates full agonistic efficacy in promoting cAMP accumulation and possesses favorable drug-like characteristics compared to the clinical drug candidate Danuglipron. Additionally, in hGLP-1R knock-in mice, compound 14 displayed a sustained pharmacological effect, effectively reducing blood glucose levels and food intake. These findings suggest that compound 14 holds promise as a future treatment option for T2DM and obesity, offering improved properties.

Design, synthesis, and evaluation of BTK-targeting PROTACs with optimized bioavailability in vitro and in vivo.

Ibrutinib is a first-line drug for the treatment of B-cell malignancies. BTKC481S mutation has led to drug resistance during clinical application. Herein, a novel BTK-targeting PROTAC molecule with better solubility and bioavailability was developed. Compound 15-271 has better solubility than ibrutinib and some reported BTK PROTACs. 15-271 has better liver microsomal stability than its analogues in multiple species. More importantly, 15-271 has a longer half-life and better bioavailability in vivo. The development strategy of compound 15-271 can be a general procedure for the optimization of other PROTACs.

Amygdala dynorphin/κ opioid receptor system modulates depressive-like behavior in mice following chronic social defeat stress.

Major depression disorder is a severe and recurrent neuropsychological disorder characterized by lowered mood and social activity and cognitive impairment. Owing to unclear molecular mechanisms of depression, limited interventions are available in clinic. In this study we investigated the role of dynorphin/κ opioid receptor system in the development of depression. Mice were subjected to chronic social defeat stress for 14 days. Chronic social defeat stress induced significant social avoidance in mice characterized by decreased time duration in the interaction zone and increased time duration in the corner zone. Pre-administration of a κ opioid receptor antagonist norBNI (10 mg/kg, i.p.) could prevent the development of social avoidance induced by chronic social defeat stress. Social avoidance was not observed in κ opioid receptor knockout mice subjected to chronic social defeat stress. We further revealed that social defeat stress activated c-fos and ERK signaling in the amygdala without affecting the NAc, hippocampus and hypothalamus, and ERK activation was blocked by systemic injection of norBNI. Finally, the expression of dynorphin A, the endogenous ligand of κ opioid receptor, was significantly increased in the amygdala following social defeat stress; microinjection of norBNI into the amygdala prevented the development of depressive-like behaviors caused by social defeat stress. The present study demonstrates that upregulated dynorphin/κ opioid receptor system in the amygdala leads to the emergence of depression following chronic social defeat stress, and sheds light on κ opioid receptor antagonists as potential therapeutic agents for the prevention and treatment of depression following chronic stress.

Proteomic analysis of male rat nucleus accumbens, dorsal hippocampus and amygdala on conditioned place aversion induced by morphine withdrawal.

Addiction is characterized by compulsive drug seeking and taking behavior, which is thought to result from persistent neuroadaptations, encoded by changes of gene expression. We previously demonstrated that the changes in synaptic plasticity were required for the formation of aversive memories associated with morphine withdrawal. However, the proteins involved in synaptic plasticity and aversive memory formation have not been well explored. In the present study, we employed a two-dimensional gel electrophoresis (2-DE)-based proteomic technique to detect the changes of protein expression in the nucleus accumbens, amygdala and dorsal hippocampus of the rats that had developed conditioned morphine withdrawal. We found that twenty-three proteins were significantly altered in the amygdala and dorsal hippocampus after conditioned morphine withdrawal. These proteins can be classified into multiple categories, such as energy metabolism, signal transduction, synaptic transmission, cytoskeletal proteins, chaperones, and protein metabolism according to their biological functions. Eight proteins related to synaptic plasticity were further confirmed by western blot analysis. It is very likely that these identified proteins may contribute to conditioned morphine withdrawal-induced neural plasticity and aversive memory formation. Thus, our work will help understand the potential mechanism associated with generation of drug withdrawal memories.

Low-frequency repetitive transcranial magnetic stimulation inhibits the development of methamphetamine-induced conditioned place preference.

The abuse of amphetamine-type stimulants (ATS) has become a global public health issue in recent years, these new-type drugs can cause addiction and serious cognitive impairment. However, there are no effective methods for the prevention and treatment of ATS addiction at present. Repetitive transcranial magnetic stimulation (rTMS) is a painless and non-invasive new therapeutic approach that has been used for the treatment of depression and other neuropsychiatric disorders, but whether it can be used to treat drug addiction is unclear. In the present study, we investigated the possible effects of rTMS on methamphetamine(METH)-induced conditioned place preference (CPP). High-frequency (10 Hz) and low-frequency stimulation patterns (1 Hz) were applied to test the effect of rTMS on METH-induced CPP. The results showed that low-frequency but not high-frequency rTMS could block METH-CPP, accompanied with a downregulation of gamma-aminobutyric acid type B receptor subunit 1 (GABABR1) expression in rat dorsolateral striatum. These results suggested that low-frequency rTMS could effectively inhibit the development of METH addiction and shed light on the rTMS as a potential approach for the prevention of drug addiction.

Anti-proliferative effect of Jesridonin on paclitaxel-resistant EC109 human esophageal carcinoma cells.

Chemoresistance to anticancer drugs is a major obstacle in the efforts to develop a successful treatment strategy for esophageal squamous carcinoma (ESCC). Thus, the exploration of new drugs and treatment strategies for combating resistance are of utmost importance. In this study, we investigated the antitumor drug resistance activity of Jesridonin, a new ent-kaurene diterpenoid, and its possible mechanisms of action using the resistant cancer cell line, EC109/Taxol. MTT assay revealed that Jesridonin had similar IC50 values against EC109 paclitaxel-sensitive cells and drug-resistant EC109/Taxol cells in vitro. In mice, Jesridonin effectively prevented the growth of EC109/Taxol tumor xenografts without exerting any significant toxicity. In addition, Jesridonin significantly inhibited the proliferation of EC109/Taxol cells, induced apoptosis and arrested the cell cycle at the G2/M phase. Furthermore, western blot analysis revealed that Jesridonin upregulated the expression of p53, p53 upregulated modulator of apoptosis (PUMA), cleaved-caspase-9 and cleaved-caspase-3 in EC109/Taxol cells, and downregulated the expression of procaspase-3, procaspase-9 and Bcl-2 in the EC109/Taxol cells in a concentration-dependent manner. Overall, our results demonstrate that Jesridonin may have potential for use in the treatment of paclitaxel-resistant ESCC. The data of the present study may lead to the development of novel treatment strategies for paclitaxel-resistant tumors.

Insights into anticancer activity and mechanism of action of a ruthenium(II) complex in human esophageal squamous carcinoma EC109 cells.

A ruthenium(II) complex [Ru(p-cymene)(NHC)Cl2] (NHC=1,3-bis(4-(tert-butyl)benzylimidazol-2-ylidene), referred to as L-4, has been designed and synthesized recently in order to look for new anticancer drugs with high efficacy and low side effects. The anticancer activity and mechanism of action of L-4 in human esophageal squamous carcinoma EC109 cells were systematically investigated. The results revealed that L-4 exerted strong inhibitory effect on the proliferation of EC109 cells, and it arrested EC109 cells at G2/M phase, accompanied with the up-regulation of p53 and p21 and the down-regulation of cyclin D1. The results also showed that the reactive oxygen species (ROS)-dependent apoptosis of EC109 can be induced by L-4 via inhibiting the activity of glutathione reductase (GR), decreasing the ratio of glutathione to oxidized glutathione (GSH/GSSG), and leading to the generation of reactive oxygen species. The mitochondria-mediated apoptosis of EC109 induced by L-4 was also observed from the increase of Bax/Bcl-2 ratio, overload of Ca(2+), disruption of mitochondrial membrane potential (MMP), redistribution of cytochrome c, and activation of caspase-3/-9. However, the effects of L-4 on the cell viability, GR activity, GSH/GSSG ratio, reactive oxygen species level, mitochondria dysfunction and apoptosis induction were remarkably attenuated by adding the reactive oxygen species scavenger, NAC. Therefore, it was concluded that L-4 can inhibit the proliferation of EC109 cells via blocking cell cycle progression and inducing reactive oxygen species-dependent and mitochondria-mediated apoptosis. These findings suggested that the ruthenium(II) complex might be a potential effective chemotherapeutic agent for human esophageal squamous carcinoma (ESCC) and worthy of further investigation.

Lipophilicity-dependent ruthenium N-heterocyclic carbene complexes as potential anticancer agents.

Five Ru(II)-N-heterocyclic carbenes (NHC) (1-5) were synthesized by reacting the appropriately substituted imidazolium chlorides with Ag2O, forming the NHC-silver chloride in situ followed by transmetalation with dimeric p-cymene ruthenium(II) dichloride. All the complexes were characterized by NMR and ESI-MS, and complex 1 was also characterized by single-crystal X-ray diffraction. The IC50 values of these five complexes were determined by the MTT-based assay on four human cancer cell lines, SKOV-3 (ovarian), PC-3 (prostate), MDA-MB-231 (breast) and EC109 (esophagus). The cytotoxicities of these complexes changed from a moderate effect to a fine one, corresponding to the increasing lipophilicity order of the complex of 2 < 1 < 3 < 4 < 5 (0.91, 0.88, 1.36, 1.85 and 2.62 for 1­5 respectively). Complex 5 showed the most cytotoxicity with the IC50 values 10.3 ± 0.3 µM for SKOV-3, 2.9 ± 0.1 µM for PC-3, 8.2 ± 0.6 µM for MDA-MB-231, 6.4 ± 0.2 µM for EC109 cell lines. Due to the superior cytotoxicity of complex 5 against the PC-3 cell lines, further biological evaluations were carried out to elucidate its action mechanism. The morphologic changes and cell cycle analysis showed that complex 5 can inhibit PC-3 cell lines by inducing cell cycle arrest at the G2/M phase. The DNA binding experiments further demonstrate that complex 5 has a better binding ability for DNA (Kb = 2.2 × 10(6) M(-1)) than complexes 1-4 (3.8 × 10(5), 7.0 × 10(5), 5.7 × 10(5), and 1.9 × 10(5) respectively).

Synthesis, crystal structure and antitumor effect of a novel copper(II) complex bearing zoledronic acid derivative.

A great majority of Cu(II) complexes currently studied in the anticancer research field exert their antiproliferative activities through ligand exchange. In this work, we present the synthesis and structural characterization of two novel Cu(II) complexes, {[Cu3(ZL)2(H2O)6]·6H2O}n (1) (ZL = 1-hydroxy-2-(1H-imidazol-1-yl)ethane-1,1-diyldiphosphonic acid) and [Cu(IPrDP)2]·3H2O (2) (IPrDP = 1-hydroxy-3-(1H-imidazol-1-yl)propane-1,1-diyldiphosphonic acid). Due to the insolubility of polymer 1 in common solvents, only the biological activities of complex 2 were investigated. The antitumor activity of complex 2 was evaluated against a panel of human cancer cell lines, including U2OS, A549, HCT116, MDA-MB-231 and HepG2. Complex 2 exhibited comparable cytotoxic effect to cisplatin (CDDP) against the human colon carcinoma cells HCT116, and superior selectivity for inhibiting human hepatocarcinoma cells rather than normal liver cells. The cell cycle distribution analysis indicates that complex 2 inhibits human carcinoma cells by inducing the cell cycle arrest at the G2/M phase, showing a similar mechanism of action to that of CDDP. The binding interaction of complex 2 with calf thymus DNA (CT-DNA) has been explored by UV-vis absorption and circular dichroism (CD), demonstrating complex 2 has a moderate binding affinity for DNA through intercalation.

KCC2 expression changes in Diazepam-treated neonatal rats with hypoxia-ischaemia brain damage.

Hypoxia-ischaemia brain damage (HIBD) is a major type of perinatal brain injury in newborns. In this study, we investigate the short- and long-term neuroprotective effects of Diazepam on neonatal rats with HIBD and the potential mechanisms underlying its protective effects. Seven-day-old Sprague-Dawley rats were subjected to left carotid artery ligation followed by a 2-h exposure to 8% oxygen and 92% nitrogen. Diazepam was administered immediately via intraperitoneal (i.p.) injection after inducing HIBD at a dose of 10 mg kg(-1)8h(-1) for three consecutive days. Three days after HIBD, rats were decapitated, and the extent of brain injury was evaluated using 2,3,5-triphenyltetrazolium chloride (TTC) staining. Additionally, the expression of Potassium-chloride cotransporter-2 (KCC2) was analysed using real-time PCR, Western blot analysis and immunohistochemistry. Three weeks after HIBD, rats were subjected to the Morris water maze (MWM) test and the locomotor activity test to determine the long-term therapeutic effects of Diazepam. We observed that the volume of infarction in the Diazepam group was significantly less (P<0.01) compared with the HIBD group. We also observed that the learning and memory abilities of the Diazepam rats improved significantly compared with the untreated rats (P<0.05) and that the decrease in KCC2 expression was prevented (P<0.01). Early treatment with Diazepam appears to attenuate HIBD and can efficiently improve the long-term learning and memory capabilities of the animal. A potential mechanism underlying these effects may involve preventing the decrease in KCC2 expression.

Establishment and characterization of a paclitaxel­resistant human esophageal carcinoma cell line.

The aim of this study was to establish a new paclitaxel (PTX)-resistant human esophageal squamous carcinoma (ESCC) cell line and investigate its biological characteristics. The resistant cell line (EC109/Taxol) was developed in vitro by intermittent exposure of the human ESCC cell line EC109 to a high concentration of PTX with time-stepwise increment over a period of 6 months. The MTT assay was performed to test the drug resistance of EC109 and EC109/Taxol cells. The morphological features were observed using inverted microscopy and apoptosis was measured by flow cytometry (FCM) and Hoechst 33258 fluorescence staining. Cell growth curves and colony formation of EC109 and EC109/Taxol cells were compared. FCM was also used to determine the distribution of the cell cycle. The protein levels of Bcl-2, Bax, Procaspase-3 and P-gp were detected by western blotting. P-gp activity was evaluated by Rh123 accumulation and efflux assay. In vivo resistance characterization was investigated. EC109/Taxol cells were 67.2-fold resistant to PTX in comparison with EC109 cells, and also exhibited cross-resistance to 5-fluorouracil (5-FU), cisplatin (CDDP) and epirubicin (EPI). FCM and Hoechst 33258 fluorescence staining confirmed that EC109 cells treated with PTX showed significantly higher percentage of apoptotic cells compared to EC109/Taxol cells. Simultaneously, EC109/Taxol cells exhibited changes in morphology, proliferation rate, doubling time, cell cycle distribution and colony formation rate were detected as compared with EC109 cells. The resistant cell line overexpressed Bcl-2, Procaspase-3 and P-gp protein, and showed decreased Bax expression. Further, EC109/Taxol cells did not change PTX resistance in vivo. This is the first report on the establishment of an EC109/Taxol cell line with higher resistance. Bcl-2, Bax, Procaspase-3 and P-gp are involved in the resistance of cell lines to PTX, which are invaluable tools to study the resistance of anticancer drugs and to identify the methods to overcome resistance.