Nanoparticle drug delivery system for the treatment of brain tumors: Breaching the blood-brain barrier.

The current status of clinical trials utilizing nanoparticle drug delivery system (NDDS) for brain tumors was summarized.Image 1.

Screening Antioxidant Components in Different Parts of Dandelion Using Online Gradient Pressure Liquid Extraction Coupled with High-Performance Liquid Chromatography Antioxidant Analysis System and Molecular Simulations.

Utilizing online gradient pressure liquid extraction (OGPLE) coupled with a high-performance liquid chromatography antioxidant analysis system, we examined the antioxidative active components present in both the aerial parts and roots of dandelion. By optimizing the chromatographic conditions, we identified the ferric reducing-antioxidant power system as the most suitable for online antioxidant reactions in dandelion. Compared to offline ultrasonic extraction, the OGPLE method demonstrated superior efficiency in extracting chemical components with varying polarities from the samples. Liquid chromatography-mass spectrometry revealed twelve compounds within the dandelion samples, with nine demonstrating considerable antioxidant efficacy. Of these, the aerial parts and roots of dandelion contained nine and four antioxidant constituents, respectively. Additionally, molecular docking studies were carried out to investigate the interaction between these nine antioxidants and four proteins associated with oxidative stress (glutathione peroxidase, inducible nitric oxide synthase, superoxide dismutase, and xanthine oxidase). The nine antioxidant compounds displayed notable binding affinities below -5.0 kcal/mol with the selected proteins, suggesting potential receptor-ligand interactions. These findings contribute to enhancing our understanding of dandelion and provide a comprehensive methodology for screening the natural antioxidant components from herbs.

Clinical observation of ultraviolet therapy combined with autologous platelet-rich plasma in the treatment of chronic refractory wounds.

Refractory wounds present complex and serious clinical dilemmas in plastic and reconstructive surgeries. Currently, there are no standard guidelines for the treatment of refractory wounds. To observe the clinical effects of ultraviolet (UV) therapy combined with autologous platelet-rich plasma (PRP) on chronic refractory wounds. Between January 2021 and December 2022, 60 inpatients with chronic refractory wounds were enrolled. Twenty patients were assigned to each of control groups 1 and 2 and treatment group according to whether they received PRP or UV treatment. All the patients underwent thorough debridement. Control group 2 received UV radiation. The treatment group underwent UV radiation combined with PRP gel covering the wound. Control group 1 underwent routine dressing changes after surgery, followed by skin grafting or skin key transfer if needed. One month later, we observed the wound healing in the two groups. After 2-4 PRP gel treatments, the wounds of patients in the treatment group healed. The healing time was 25.25 ± 4.93 days, and the dressings were changed 4.15 ± 3.30 times, both of which were better outcomes than in both control groups. In the treatment group, epidermal growth factor (EGF), insulin-like growth factor (IGF), platelet-derived growth factor (PGF), and transforming growth factor ß (TGF-ß) were slightly higher, and the concentration of vascular endothelial growth factor (VEGF) was significantly higher than in the control group (p < 0.05). PRP combined with UV therapy significantly increased the concentration of wound growth factors, accelerated wound healing, shortened treatment time, reduced treatment costs, and alleviated pain in patients.

Transcriptional profiling of rat skeletal muscle hypertrophy under restriction of blood flow.

Blood flow restriction (BFR) under low-intensity resistance training (LIRT) can produce similar effects upon muscles to that of high-intensity resistance training (HIRT) while overcoming many of the restrictions to HIRT that occurs in a clinical setting. However, the potential molecular mechanisms of BFR induced muscle hypertrophy remain largely unknown. Here, using a BFR rat model, we aim to better elucidate the mechanisms regulating muscle hypertrophy as induced by BFR and reveal possible clinical therapeutic targets for atrophy cases. We performed genome wide screening with microarray analysis to identify unique differentially expressed genes during rat muscle hypertrophy. We then successfully separated the differentially expressed genes from BRF treated soleus samples by comparing the Affymetrix rat Genome U34 2.0 array with the control. Using qRT-PCR and immunohistochemistry (IHC) we also analyzed other related differentially expressed genes. Results suggested that muscle hypertrophy induced by BFR is essentially regulated by the rate of protein turnover. Specifically, PI3K/AKT and MAPK pathways act as positive regulators in controlling protein synthesis where ubiquitin-proteasome acts as a negative regulator. This represents the first general genome wide level investigation of the gene expression profile in the rat soleus after BFR treatment. This may aid our understanding of the molecular mechanisms regulating and controlling muscle hypertrophy and provide support to the BFR strategies aiming to prevent muscle atrophy in a clinical setting.

[Research advance on signaling pathways and protein metabolism for skeletal muscle disuse atrophy].

Disuse atrophy of skeletal muscle is a common clinical problem and its exact mechanisms have not been fully understood. Previous studies suggested that disuse muscle atrophy is realized through the activation of one or more cell signaling pathways, but studies have shown that disuse atrophy is the activation of the ubiquitin-proteasome caused extensive decomposition of the protein. The present researches for disuse atrophy mainly focus on regulatory role in the upstream signaling molecules MuRF1 and Atroginl/MAFbx by NF-kappaB, IGF-1/PI3K/Akt, TGF-beta/Smad and MAPK signal pathway and a plurality of signal pathway activation or inhibition and interaction,and then through the ubiquitin--proteasome to influence the metabolism of protein. But regulation of expression of MuRF1 and Atroginl/MAFbxs still to be studied. Participate in disuse atrophy also needs to be further studied with atrophy confirmation and functional gene verification. The paper summarized recent original articles about the researches of skeletal muscle disuse atrophy and reviewed the various signal pathways and related u-biquitin-proteasome protein metabolism of disuse muscle atrophy.

EPR and ENDOR studies of dimeric paracyclophane radical cations and dications containing tri- and pentamethylene-bridged p-phenylene diamine units.

Solution EPR and ENDOR studies on the radical cations of three dimeric p-phenylene diamine (PD)-based compounds, the tetraisopropyl-substituted bis-trimethylene-bridged [5,5]paracyclophane 1(iPr)(+) and its tetramethyl- and tetraisopropyl-substituted bis-pentamethylene-bridged [7,7]paracyclophane analogues 3(Me)(+) and 3(iPr)(+), showed that charge is localized on one PD(+) unit on the EPR time scale in all three compounds and determined the nitrogen splitting constants and several of the hydrogen splitting constants for these complex spectra. Rigid glass studies of the diradical dications of 1(iPr)(2+), 3(iPr)(2+), and its tetramethylene-bridged [6,6]paracyclophane analogue 2(iPr)(2+), all of which show significant amounts of thermally excited triplet at low temperature, demonstrated that 1(iPr)(2+) has a singlet ground state but the triplet lies only 0.07 kcal/mol higher in energy, and 3(iPr)(2+) has its triplet lying 0.05 kcal/mol higher in energy than its singlet.

Solution and solid-state studies of doubly trimethylene-bridged tetraalkyl p-phenylenediamine diradical dication conformations.

X-ray crystallographic structures are reported for 1(Me)(2+)(SbCl(6)(-))(2) x 2 CH(3)CN, 2(Et)(2+)(SbF(6)(-))(2) x 2 CH(3)CN x 2 CH(2)Cl(2), and 1(iPr)(2+)(SbF(6)(-))(2), which also contained unresolved solvent and is in a completely different conformation than the methyl- and ethyl-substituted compounds. A quite different structure of 1(Me)(2+)(SbF(6)(-))(2) than that previously published was obtained upon crystallizing it from a mixture rich in monocation. It does not contain close intramolecular PD(+),PD(+) contacts but has close intermolecular ones. Low temperature NMR spectra of 1(Me)(2+) and 1(Et)(2+) in 2:1 CD(3)OD/CD(3)CN showed that both contain three conformations of all-gauche NCCC unit material with close intramolecular PD(+),PD(+) contacts. In addition to the both PD(+) ring syn and anti material that had been seen in the crystal structure of 1(Me)(2+)(SbF(6)(-))(2) x 2 CH(3)CN published previously, an unsymmetrical conformation having one PD(+) ring syn and the other anti (abbreviated uns) was seen, and the relative amounts of these conformations were significantly different for 1(Me)(2+) and 1(Et)(2+). Calculations that correctly obtain the relative amounts of both the methyl- and ethyl-substituted material as well as changes in the optical spectra between 1(Me)(2+) and 1(Et)(2+), which contains much less of the uns conformation, are reported.

O-capped heteroadamantyl-substituted hydrazines and their oxidation products.

The mixed valence bishydrazine radical cation 6(+), obtained by oxidation of 2,6-bi-(2'-oxa-6'-azaadamantane-6'-yl)-2,6-diazaadamantane-2,6-diyl (6) with silver or nitrosonium salts, has been prepared and studied. 6 is obtained along with lesser amounts of the trishydrazine, some of the tetrahydrazine, and apparently traces of the pentahydrazine upon reaction of deprotonated 2-oxa-6-azaadamantane with 2,6-dichloro-2,6-diazaadamantane. The EPR spectrum of 6(+) shows that its charge is localized on one hydrazine unit on the EPR time scale. It shows a Hush-type Robin-Day class II mixed valence band in its optical spectrum despite the fact that the nitrogen lone pairs are held in a perpendicular geometry that would lead to no electronic interaction between the nitrogen atoms that are separated by only four sigma bonds if its nitrogens were planar. The electron transfer distance that is estimated from the calculated dipole moment of 6(+) is the same as that obtained using the average distance between the electrons of the triplet state of the dication 6(2+), calculated from its dipolar EPR splitting, as a model for the electron transfer distance of 6(+), 3.7 A. Using Hush's Gaussian approximation for the optical spectrum with this electron transfer distance produces an estimate of the electronic coupling V(ab) through the saturated bridge of about 400 cm(-1), which is consistent with the observed EPR spectrum of 6(+). From the observed dipolar splitting, the trishydrazine diradical dication has its remote hydrazine units oxidized, although the monocation presumably forms at the central hydrazine unit, which lacks substitution by the more electron-withdrawing oxygen atoms.

Cyclin B1 is an efficacy-predicting biomarker for Chk1 inhibitors.

Chk1 is the major mediator of cell-cycle checkpoints in response to various forms of genotoxic stress. Although it was previously speculated that checkpoint abrogation due to Chk1 inhibition may potentiate the efficacy of DNA-damaging agents through induction of mitotic catastrophe, there has not been direct evidence proving this process. Here, through both molecular marker and morphological analysis, we directly demonstrate that specific downregulation of Chk1 expression by Chk1 siRNA potentiates the cytotoxicities of topoisomerase inhibitors through the induction of premature chromosomal condensation and mitotic catastrophe. More importantly, we discovered that the cellular cyclin B1 level is the major determinant of the potentiation. We show that downregulation of cyclin B1 leads to impairment of the induction of mitotic catastrophe and correspondingly a reduction of the potentiation ability of either Chk1 siRNA or a small molecule Chk1 inhibitor. More significantly, we have extended the study by examining a panel of 10 cancer cell-lines with different tissue origins for their endogenous levels of cyclin B1 and the ability of a Chk1 inhibitor to sensitize the cells to DNA-damaging agents. The cellular levels of cyclin B1 positively correlate with the degrees of potentiation achieved. Of additional interest, we observed that the various colon cancer cell lines in general appear to express higher levels of cyclin B1 and also display higher sensitivity to Chk1 inhibitors, implying that Chk1 inhibitor may be more efficacious in treating colon cancers. In summary, we propose that cyclin B1 is a biomarker predictive of the efficacy of Chk1 inhibitors across different types of cancers. Unlike previously established efficacy-predictive biomarkers that are usually the direct targets of the therapeutic agents, cyclin B1 represents a non-drug-target biomarker that is based on the mechanism of action of the target inhibitor. This finding may be potentially very useful for the stratification of patients for Chk1 inhibitor clinical trials and hence, maximize its chance of success.

Alkylated trimethylene-bridged bis(p-phenylenediamines).

One and two electron oxidation of N,N',N'',N'''-tetramethyl-1,5,12,16-tetraaza[5,5]paracyclophane (Me3C), a bis-trimethylene bridged bis-p-phenylene diamine (PD), and its ethyl and isopropyl analogues are discussed. The monocation and dication are both stable, as demonstrated by optical studies that show they are in equilibrium in solution, with an especially small difference in first and second oxidation potentials for Me3C in MeCN (+23 to -20 mV, measured by simulation of the optical spectrum and of the cyclic voltammogram, respectively). The monocations have charge localized in one PD unit and show a Hush-type mixed valence transition between their PD0 and PD.+ groups. The dications Me3C2+ and Et3C2+ have optical spectra that appear to show large splittings between their PD.+ groups and have a weak ESR spectrum, and 1H NMR data show that the former is a ground-state singlet. iPr3C2+ has a very different optical spectrum and exhibits a triplet ESR spectrum at 120 K. X-ray crystal structures show that for Me3C0 the N(CH2)3N units on each side are in doubly anti (aa) conformations that put the aryl rings as far apart as possible, but Me3C2+ has doubly gg N(CH2)3N trimethylene bridges and both N,N and C,C distances between the PD.+ groups that are significantly below van der Walls contact. In contrast, iPr3C0 is in a doubly ag conformation, and its diradical dication is suggested to be a triplet because it does not attain the doubly gg conformation.

Synthesis and in-vitro biological activity of macrocyclic urea Chk1 inhibitors.

A variety of macrocyclic urea compounds were prepared as potent Chk1 inhibitors by modifying the C5 position of the benzene ring of the macrocyclic urea with ether moieties, aliphatic carbon chains, amide and halides. Enzymatic activity less than 20nM was observed in 29 of 40 compounds. Compounds 14, 46d, and 48j provided the best overall results in the cellular assays as they abrogated doxorubicin-induced cell cycle arrest (IC(50)=3.31, 3.08, and 3.13microM) and enhanced doxorubicin cytotoxicity (IC(50)=0.54, 1.27, and 0.96microM) while displaying no single agent activity, respectively.

Cyanopyridyl containing 1,4-dihydroindeno[1,2-c]pyrazoles as potent checkpoint kinase 1 inhibitors: improving oral biovailability.

A series of 1,4-dihydroindeno[1,2-c]pyrazole compounds with a cyanopyridine moiety at the 3-position of the tricyclic pyrazole core was explored as potent CHK-1 inhibitors. The impact of substitutions at the 6 and/or 7-position of the core on pharmacokinetic properties was studied in detail. Compounds carrying a side chain with an ether linker at the 7-position and a terminal morpholino group, such as 29 and 30, exhibited much-improved oral biovailability in mice as compared to earlier generation inhibitors. These compounds also possessed desirable cellular activity in potentiating doxorubicin and will serve as valuable tool compounds for in vivo evaluation of CHK-1 inhibitors to sensitize DNA-damaging agents.

Discovery of 4'-(1,4-dihydro-indeno[1,2-c]pyrazol-3-yl)-benzonitriles and 4'-(1,4-dihydro-indeno[1,2-c]pyrazol-3-yl)-pyridine-2'-carbonitriles as potent checkpoint kinase 1 (Chk1) inhibitors.

An extensive structure-activity relationship study of the 3-position of a series of tricyclic pyrazole-based Chk1 inhibitors is described. As a result, 4'-(1,4-dihydro-indeno[1,2-c]pyrazol-3-yl)-benzonitriles (4) and 4'-(1,4-dihydro-indeno[1,2-c]pyrazol-3-yl)-pyridine-2'-carbonitriles (29) emerged as new lead series. Compared with the original lead compound 2, these new leads fully retain the biological activity in both enzymatic inhibition and cell-based assays. More importantly, the new leads 4 and 29 exhibit favorable physicochemical properties such as lower molecular weight, lower Clog P, and the absence of a hydroxyl group. Furthermore, structure-activity relationship studies were performed at the 6- and 7-positions of 4, which led to the identification of ideal Chk1 inhibitors 49, 50, 51, and 55. These compounds not only potently inhibit Chk1 in an enzymatic assay but also significantly potentiate the cytotoxicity of DNA-damaging agents in cell-based assays while they show little single agent activity. A cell cycle analysis by FACS confirmed that these Chk1 inhibitors efficiently abrogate the G2/M and S checkpoints induced by DNA-damaging agent. The current work paved the way to the identification of several potent Chk1 inhibitors with good pharmacokinetics that are suitable for in vivo study with oral dosing.

Design, synthesis, and biological activity of 5,10-dihydro-dibenzo[b,e][1,4]diazepin-11-one-based potent and selective Chk-1 inhibitors.

A novel series of 5,10-dihydro-dibenzo[b,e][1,4]diazepin-11-ones have been synthesized as potent and selective checkpoint kinase 1 (Chk1) inhibitors via structure-based design. Aided by protein X-ray crystallography, medicinal chemistry efforts led to the identification of compound 46d, with potent enzymatic activity against Chk1 kinase. While maintaining a low cytotoxicity of its own, compound 46d exhibited a strong ability to abrogate G2 arrest and increased the cytotoxicity of camptothecin by 19-fold against SW620 cells. Pharmacokinetic studies revealed that it had a moderate bioavailabilty of 20% in mice. Two important binding interactions between compound 46b and Chk1 kinase, revealed by X-ray cocrystal structure, were hydrogen bonds between the hinge region and the amide bond of the core structure and a hydrogen bond between the methoxy group and Lys38 of the protein.

Synthesis and biological evaluation of 4'-(6,7-disubstituted-2,4-dihydro-indeno[1,2-c]pyrazol-3-yl)-biphenyl-4-ol as potent Chk1 inhibitors.

A new series of potent tricyclic pyrazole-based Chk1 inhibitors are described. Analogues disubstituted on the 6- and 7-positions show improved Chk1 inhibition potency compared with analogues with a single substituent on either the 6- or 7-position. Based on the lead compound 4'-(6,7-dimethoxy-2,4-dihydro-indeno[1,2-c]pyrazol-3-yl)-biphenyl-4-ol (2), detailed SAR studies on the 6- and 7-positions were performed. 3'-morpholin-4'-yl-propoxy, pyridin-4'-ylmethoxy, pyridin-3'-ylmethoxy, 2'-(5''-ethyl-pyridin-2''-yl)-ethoxy, pyridin-2'-ylethoxy, (6'-methyl-pyridin-2'-yl)-propoxyethoxy, 2',3'-dihydroxyl-1'-yl-propoxy, and tetrahydro-furan-3'-yloxy have been identified as the best groups on the 6-position when the 7-position is substituted with methoxyl group. Pyridin-2'-ylmethoxy and pyridin-3'-ylmethoxy have been identified as the best substituents at the 7-position while the 6-position bearing methoxyl group. These compounds significantly potentiate the cytotoxicity of DNA-damaging antitumor agents in a cell-based assay and efficiently abrogate the doxorubicin-induced G2/M and the camptothecin-induced S checkpoints, suggesting that their potent biological activities are mechanism-based through Chk1 inhibition.

Selective Chk1 inhibitors differentially sensitize p53-deficient cancer cells to cancer therapeutics.

The majority of cancer therapeutics induces DNA damage to kill cells. Normal proliferating cells undergo cell cycle arrest in response to DNA damage, thus allowing DNA repair to protect the genome. DNA damage induced cell cycle arrest depends on an evolutionarily conserved signal transduction network in which the Chk1 kinase plays a critical role. In mammalian cells, the p53 and RB pathways further augment the cell cycle arrest response to prevent catastrophic cell death. Given the fact that most tumor cells suffer defects in the p53 and RB pathways, it is likely that tumor cells would depend more on the Chk1 kinase to maintain cell cycle arrest than would normal cells. Therefore Chk1 inhibition could be used to specifically sensitize tumor cells to DNA-damaging agents. We have previously shown that siRNA-mediated Chk1 knockdown abrogates DNA damage-induced checkpoints and potentiates the cytotoxicity of several DNA-damaging agents in p53-deficient cell lines. In this study, we have developed 2 potent and selective Chk1 inhibitors, A-690002 and A-641397, and shown that these compounds abrogate cell cycle checkpoints and potentiate the cytotoxicity of topoisomerase inhibitors and gamma-radiation in p53-deficient but not in p53-proficient cells of different tissue origins. These results indicate that it is feasible to achieve a therapeutic window with 1 or more Chk1 inhibitors in potentiation of cancer therapy based on the status of the p53 pathway in a wide spectrum of tumor types.

Synthesis and biological evaluation of 1-(2,4,5-trisubstituted phenyl)-3-(5-cyanopyrazin-2-yl)ureas as potent Chk1 kinase inhibitors.

Based on the X-ray crystallography of our lead compound 1-(5-chloro-2,4-dimethoxyphenyl)-3-(5-cyanopyrazin-2-yl)urea in the checkpoint kinase 1 (Chk1) enzyme, we modified R4, and to a lesser extent, R2, and R5 of the phenyl ring, and made a variety of N-aryl-N'-pyrazinylurea Chk1 inhibitors. Enzymatic activity less than 20 nM was observed in 15 of 41 compounds. Compound 8i provided the best overall results in the cellular assays as it abrogated doxorubicin-induced cell cycle arrest (IC50=1.7 microM) and enhanced doxorubicin cytotoxicity (IC50=0.44 microM) while displaying no single agent activity.

1-(5-Chloro-2-alkoxyphenyl)-3-(5-cyanopyrazin-2-yl)ureas [correction of cyanopyrazi] as potent and selective inhibitors of Chk1 kinase: synthesis, preliminary SAR, and biological activities.

The discovery of 1-(5-chloro-2-alkoxyphenyl)-3-(5-cyanopyrazin-2-yl)ureas as a new class of potent (IC(50) values of 3-10 nM) and selective inhibitors of Chk1 kinase was described. One of these compounds (2e) potentiates HeLa cells by over 22-fold against doxorubicin in an antiproliferation assay, and SW620 cells against camptothecin by 20-fold in an antiproliferation assay and 14-fold in a soft agar assay. Flow cytometry (FACS) analysis confirmed that 2e abrogated G2 checkpoint arrest of H1299 cells caused by doxorubicin and S checkpoint arrest caused by camptothecin.

Optimization and metabolic stabilization of a class of nonsteroidal glucocorticoid modulators.

The optimization of a series of nonsteroidal glucocorticoid modulators is reported. Potent selective GR ligands that have improved metabolic stability were discovered typified by the subnanomolar acid 12 (GR binding IC(50)=0.6 nM).