RESUMEN

Delicaflavone (DF), a natural active ingredient from Selaginella doederleinii Hieron, has been reported to have favorable anticancer effects and is thus considered a potential anticancer agent. However, its pharmacokinetics and plasma protein binding properties remain unknown. Here, we investigated the pharmacokinetic profile of DF in rats using a validated HPLC-MS/MS methods, as well as its human serum albumin (HSA) binding properties through multi-spectroscopic and in silico methods. The results showed that DF was rapidly eliminated and had a widespread tissue distribution after intravenous administration. DF showed linear dynamics in the dose range of 30-60 mg/kg and poor oral bioavailability. The major distribution tissues of DF were the liver, lungs, and kidneys. Ultraviolet and fluorescence spectroscopy and molecular docking demonstrated that DF had a static quenching effect on HSA, with one binding site, and relatively strong binding constants. Thermodynamic analysis of the binding data revealed that hydrogen bonding and van der Waals interactions played major roles in binding. The results of this study further our understanding of the pharmacokinetic and plasma protein binding properties of the potential anticancer agent DF and shed light on pharmacological strategies that may be useful for the development of novel cancer therapeutics.

RESUMEN

Targeting cancer-related Hsp70-Bim protein-protein interactions (PPIs) offers a new strategy for the design of Hsp70 inhibitors. Herein, we discovered a novel Hsp70 inhibitor, S1g-6, based on the established BH3 mimetics. S1g-6 exhibited sub-µM binding affinity toward Hsp70 and selectively disrupted Hsp70-Bim PPI. The target specificity of S1g-6in situ was validated by affinity-based protein profiling, co-immunoprecipitation, and cell-based shRNA assays. S1g-6 specifically antagonized the ATPase activity of Hsp70 upon recruiting Bim and showed selective apoptosis induction in some cancer cell lines over normal ones through suppression of some oncogenic clients of Hsp70, representing a new class of antitumor candidates. Hsp70-Bim PPI exhibited cancer-dependent role as a potential anti-cancer target.

Asunto(s)

Antineoplásicos/farmacología , Proteína 11 Similar a Bcl2/antagonistas & inhibidores , Proteínas HSP70 de Choque Térmico/antagonistas & inhibidores , Antineoplásicos/química , Proteína 11 Similar a Bcl2/química , Relación Dosis-Respuesta a Droga , Proteínas HSP70 de Choque Térmico/química , Humanos , Estructura Molecular , Unión Proteica , Relación Estructura-Actividad

RESUMEN

OBJECTIVE：To investigate th e stabilities of antitumor candid ate Gedatolisib in plasma in vitro and simulated gastric/intestinal fluids ，and to analyze the possible catabolites in plasma. METHODS ：HPLC method was adopted. Using indometacin as internal standard ，the contents of Gedatolisib incubated in plasma of SD rats （male）for 0，0.5，1.0，1.5，2.0，3.0 h and blank simulated gastric fluid （pH 1.3，no enzyme ），blank simulated intestinal fluid （pH 6.8，no enzyme ），simulated gastric fluid（pH 1.3，containing pepsin ）and simulated intestinal fluid （pH 6.8，containing trypsin ）for 0，0.5，1.0，2.0，3.0，4.0，6.0 h were determined. The remaining percentage of Gedatolisib was calculated. UPLC-Q-TOF/MS was used to analyze the TIC of blank plasma and incubated samples. The differential peaks were compared， and catabolites were inferred by MS 1Z073）.gzwjkj2019-1- chromatograms. RESULTS ： The remaining percentage in plasma of rats for 2.0 h was about 63％，and there was nosignificant change after continued incubation. The remaining percentage of Gedatolisib incubated in blank simulated intestinal fluid for different time ranged （99.18 ± 2.15）％ -（103.20 ± 3.41）％ . The remaining percentage in simulated com intestinal fluids for 2.0 h ranged （88.76 ± 1.53）％ . The remaining percentage in blank simulated gastric fluids for 2.0 h was ranged （85.63±1.55）％，and there was no significant change after continued incubation. The remaining percentage in simulated gastric fluid was from （94.94±3.52）％（0 h）to（16.19±1.17）％ （6.0 h）. TIC of UPLC-Q-TOF/MS showed that the differential peaks of incubated samples and blank plasma was 6.42 min under positive mode scanning ，molecular ion peak of m/z 616.335 1，simulated 632.327 7，630.317 0，602.278 6 [M+H]+ could be found in scanning channel. It was speculated that Gedatolisib could generate 1-（4-（3-（4，6-dimorpholino-1，3，5-triazin-2-yl）phenyl）urea） benzoyl）-N，N-dimethylpiperidin-4-amine oxide ，1-（4-（4-（dimethylamino）piperidine-1-carbonyl）phenyl）-3-（4-（4-morpholino-6- （3-oxomorpholino）-1，3，5-triazin-2-yl）phenyl）urea and 1-（4-（3-（4-（4，6-dimorpholino-1，3，5-triazin-2-yl）phenyl）urea） benzoyl）-N-methylpiperidine. CONCLUSIONS ：Gedatolisib is not stable in rat plasma ，and it may undergo terminal N oxidation， morpholine ring oxidation and terminal N demethylation. Gedatolisib is stable in artificial intestinal fluid and blank artificial gastric/ intestinal fluid ，and degrades obviously in the presence of pepsin.