Search Results (6)

The internal tandem duplication mutation of FMS-like tyrosine kinase 3 (FLT3-ITD) is associated with high recurrence and mortality rates in acute myeloid leukemia (AML), making it a critical target for anti-AML therapies. Plinabulin is a diketopiperazines derivative that exhibits extensive anti-cancer potency by targeting β-tubulin. We designed and synthesized a novel FLT3 inhibitor, namely 5-3, based on the structure of plinabulin and evaluated its effect on FLT3-ITD mutant AML cells. The results indicated that 5-3 potently and selectively inhibits the growth of mutant FLT3-expressingleukemia cells, and had no effect on FLT3 wide-type cancer cells, suggesting the antiproliferative activity of 5-3 depends highly on FLT3-ITD expression. Mechanically, 5-3 significantly suppressed the phosphorylation of FLT3 signaling pathway, including STAT5, Erk and Akt. Moreover, the efficiency of compound 5-3 is not associated with Plinabulin’s typical target, β-tubulin. In conclusion, the study identified diketopiperazine derivative as a novel FLT3-ITD selective inhibitor. These results demonstrated that 5-3 might be a drug candidate for the treatment of FLT3-ITD-positive AML. Full article

Plinabulin, a new antitumor drug developed from marine natural products that targets microtubules in cancer cells, is currently being tested in a phase III clinical study. Plinabulin has been clinically proven to be effective on leukopenia. However, to our knowledge, there are no reports investigating the pharmacokinetics of plinabulin in individuals with leukopenia and healthy individuals. In this study, we developed a rapid and sensitive UHPLC-MS/MS method for the detection of plinabulin for the first time. Using a novel cyclophosphamide-induced leukopenia model, we investigated the differences in the pharmacokinetic characteristics of plinabulin between rats with leukopenia and normal rats. Plinabulin and propranolol (IS) peaks were separated by gradient elution for a total run time of 5 min. The methodological validation showed a good accuracy (101.96–109.42%) and precision (RSD ≤ 5.37%) with the lower limit of quantification at 0.5 ng/mL. The recovery of plinabulin was between 91.99% and 109.75% (RSD ≤ 7.92%). The values of the area under the plasma concentration-time curve (AUC_0-t) for leukopenia groups and control groups at doses of 0.5 mg/kg, 1 mg/kg, and 3 mg/kg were 148.89 ± 78.74 h·μg/L and 121.75 ± 31.56 h·μg/L; 318.15 ± 40.00 h·μg/L and 272.06 ± 42.85 h·μg/L; and 1432.43 ± 197.47 h·μg/L and 1337.12 ± 193.56 h·μg/L; respectively. The half-lives (t_1/2s) of plinabulin were 0.49–0.72 h for leukopenia groups and 0.39–0.70 h for control groups at three doses, and the clearance rates (CLs) of plinabulin were 2.13–3.87 L/h/kg for leukopenia groups and 2.29–4.23 L/h/kg for control groups. Pharmacokinetic results showed that there was no significant pharmacokinetic difference between the normal group and the leukopenia group. Based on the power model, plinabulin exhibits a lack of dose proportionality over the dose range of 0.5–3 mg/kg after intravenous administration. This study provides guidance for the development of plinabulin as a potential candidate for the treatment of chemotherapy-induced leukopenia. Full article

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections have triggered a recent pandemic of respiratory disease and affected almost every country all over the world. A large amount of natural bioactive compounds are under clinical investigation for various diseases. In particular, marine natural compounds are gaining more attention in the new drug development process. The present study aimed to identify potential marine-derived inhibitors against the target proteins of COVID-19 using a computational approach. Currently, 16 marine clinical-level compounds were selected for computational screening against the 4 SARS-CoV-2 main proteases. Computational screening resulted from the best drug candidates for each target based on the binding affinity scores and amino acid interactions. Among these, five marine-derived compounds, namely, chrysophaentin A (−6.6 kcal/mol), geodisterol sulfates (−6.6 kcal/mol), hymenidin (−6.4 kcal/mol), plinabulin (−6.4 kcal/mol), and tetrodotoxin (−6.3 kcal/mol) expressed minimized binding energy and molecular interactions, such as covalent and hydrophobic interactions, with the SARS CoV-2 main protease. Using molecular dynamic studies, the root-mean-square deviation (RMSD), root-mean-square fluctuation (RMSF), radius of gyration (ROG), and hydrogen bond (H-Bond) values were calculated for the SARS-CoV-2 main protease with a hymenidin docked complex. Additionally, in silico drug-likeness and pharmacokinetic property assessments of the compounds demonstrated favorable druggability. These results suggest that marine natural compounds are capable of fighting SARS-CoV-2. Further in vitro and in vivo studies need to be carried out to confirm their inhibitory potential. Full article

PharmaSea performed large-scale in vivo screening of marine natural product (MNP) extracts, using zebrafish embryos and larvae, to identify compounds with the potential to treat epilepsy. In this study, we report the discovery of two new antiseizure compounds, the 2,5-diketopiperazine halimide and its semi-synthetic analogue, plinabulin. Interestingly, these are both known microtubule destabilizing agents, and plinabulin could have the potential for drug repurposing, as it is already in clinical trials for the prevention of chemotherapy-induced neutropenia and treatment of non-small cell lung cancer. Both halimide and plinabulin were found to have antiseizure activity in the larval zebrafish pentylenetetrazole (PTZ) seizure model via automated locomotor analysis and non-invasive local field potential recordings. The efficacy of plinabulin was further characterized in animal models of drug-resistant seizures, i.e., the larval zebrafish ethyl ketopentenoate (EKP) seizure model and the mouse 6 Hz psychomotor seizure model. Plinabulin was observed to be highly effective against EKP-induced seizures, on the behavioral and electrophysiological level, and showed activity in the mouse model. These data suggest that plinabulin could be of interest for the treatment of drug-resistant seizures. Finally, the investigation of two functional analogues, colchicine and indibulin, which were observed to be inactive against EKP-induced seizures, suggests that microtubule depolymerization does not underpin plinabulin’s antiseizure action. Full article

The role of the marine environment in the development of anticancer drugs has been widely reviewed, particularly in recent years. However, the innovation in terms of clinical benefits has not been duly emphasized, although there are important breakthroughs associated with the use of marine-derived anticancer agents that have altered the current paradigm in chemotherapy. In addition, the discovery and development of marine drugs has been extremely rewarding with significant scientific gains, such as the discovery of new anticancer mechanisms of action as well as novel molecular targets. Approximately 50 years since the approval of cytarabine, the marine-derived anticancer pharmaceutical pipeline includes four approved drugs and eighteen agents in clinical trials, six of which are in late development. Thus, the dynamic pharmaceutical pipeline consisting of approved and developmental marine-derived anticancer agents offers new hopes and new tools in the treatment of patients afflicted with previously intractable types of cancer. Full article

Derivatives of the new ring systems bispyrido[4',3':4,5]pyrrolo[1,2-a:1',2'-d] pyrazine-6,13-dione and its deaza analogue pyrido[4'',3'':4',5']pyrrolo-[1',2':4,5]pyrazino [1,2-a]indole-6,13-dione were conveniently synthesized through a four-step sequence. Symmetrical derivatives of the former ring system were obtained through self condensation. On the other hand, condensation of 6-azaindole carboxylic acid with indole 2-carboxylic acid afforded the deaza analogue ring system. Derivatives of the title ring system were tested by the National Cancer Institute (Bethesda, MD, USA) and four of them exhibited modest activity against MCF7 (a breast cancer cell line) and/or UO-31 (a renal cancer cell line). Full article