Renal evaluation of Aotus azarai infulatus by ultrasonography and serum chemistry profile

This study aimed to characterize anatomical and biochemical properties of owl monkey kidneys in order to provide normal reference values. Sixty-nine Aotus azarai infulatus (45 males and 24 females) were divided into four different age groups (AG1: 3 months-1 year; AG2: 2-3 years; AG3: 4-6 years; and AG4: over 7 years old). The monkeys were evaluated with a serum chemistry profile, focusing on serum creatinine (SCr) and blood urea nitrogen (BUN) and with ultrasound. Mean body mass differed among the age groups. This significance was attributed to AG1 body mass being significantly lower than in AG2 and that in both AG2 and AG3 being significantly lower than in the two older age groups (AG3 and AG4). SCr and BUN concentrations differed significantly between the sexes and SCr level correlated positively with age. In contrast, renal measurements did not differ between males and females. Left and right renal volumes did not differ significantly within age groups, or among AG2, AG3, and AG4. Renal volumes in AG1, however, while not differing from those in AG2, did differ significantly from those in AG3 and AG4. In conclusion, this study provides ultrasonographic reference values for the morphology the kidneys in A. a. infulatus. Evidence is also provided that SCr and BUN levels in owl monkeys are influenced by the sex and age of the individual, factors that should be considered when interpreting test results.     

Evaluation of the racemate and the enantiomers of a new highly active and selective aromatase inhibitor of the aminoglutethimide type.

Compound 1 [3-(4-aminophenyl)-3-cyclohexylpiperidine-2,6-dione] is a highly potent nonsteroidal aromatase inhibitor of the aminoglutethimide (AG)-type containing an asymmetric carbon atom. 1 and its enantiomers (+)-1 and (-)-1 inhibited human placental aromatase by 50% at 0.3, 0.15, and 4.6 microM, respectively (IC50 AG = 37 microM). A competitive type of inhibition was observed for 1 and (+)-1 (Ki 1 = 3.9 nM, Ki (+)-1 = 2.0 nM, Ki AG = 408 nM). Using solubilized high spin aromatase, 1 showed a type II difference spectrum indicating the interaction of the amino nitrogen with the central Fe(III)-ion of the cytochrome P450 heme component. 1 and (+)-1 inhibited cholesterol side chain cleavage enzyme (desmolase) by 50% at 67 and 82 microM, respectively (IC50 AG = 29 microM). In ACTH-stimulated rat adrenal tissue in vitro, 1 was less active in inhibiting aldosterone and corticosterone production compared to AG (IC50s, 1, 130 and 140 microM, AG, 80 and 50 microM, respectively). In vivo, 1 was superior to AG, too: it showed a stronger inhibition of the plasma estradiol concentration of pregnant mares' serum gonadotropin-primed SD rats, the activity residing mainly in the (+)-enantiomer [ovarian vein: (+)-1, 0.31 mg/kg: 81% inhibition, (-)-1, 0.31 mg/kg: 6%, AG, 1.25 mg/kg: 35%]. Furthermore 1 was much more active in inhibiting the testosterone-stimulated tumor growth of the ovariectomized 9,10-dimethyl-1,2-benzanthracene tumor-bearing SD rat (postmenopausal model). Up to a dose of 600 mg/kg of 1 no central nervous symptom depressive effects were observed in the motility test and the rotarod experiment, whereas AG exhibited ED50s of 62 and 164 mg/kg, respectively.     

Beneficial role of aminoguanidine on acute cardiomyopathy related to doxorubicin-treatment

Doxorubicin (DOX) is a broad-spectrum anthracycline antibiotic that has cardiotoxicity as a major side effect. One mechanism of this toxicity is believed to involve the reactive oxygen radical species (ROS); these agents likely account for the pathophysiology of DOX-induced cardiomyopathy. Aminoguanidine (AG) is an effective antioxidant and free radical scavenger which has long been known to protect against ROS formation. We investigated the effects of AG on DOX-induced changes in thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH) content. The rats were divided into four groups:1) Control; 2) DOX group; injected intraperitoneally (i.p.) with DOX 20 mg/kg in a single dose 3) AG-treated group; injected i.p. in single dose of 20 mg/kg DOX plus 100 mg/kg AG 1 h before the DOX for 3 days, 4) AG group; injected i.p. with AG 100 mg/kg for 3 days. DOX administration to control rats increased TBARS and decreased GSH levels. AG administration before DOX injection caused significant decrease in TBARS and increase in GSH levels in the heart tissue when compared with DOX only. Morphological changes, including severe myocardial fibrosis and inflammatory cell infiltration were clearly observed in the DOX-treated heart. AG reversed the DOX-induced heart damage. Therefore AG could protect the heart tissue against free radical injury. The application of AG during cancer chemotherapy may attenuate tissue damage and improve the therapeutic index of DOX.     

Transport of 1,5-anhydro-D-glucitol across plasma membranes in rat hepatoma cells

The transport of 1,5-anhydro-D-glucitol (AG) across plasma membranes was investigated in rat hepatoma cells, Reuber H-35. The AG uptake by the cells showed a concentration gradient dependency: the uptake was saturated within 40 s, which was less than one-third of the saturation time for 2-deoxy-D-glucose (DG) uptake. Furthermore, the Km value of the transport system for AG was higher than 100 mM. Though AG has a pyranoid structure resembling that of glucose, AG did not compete for cellular uptake with DG, D-glucose or 3-O-methyl-D-glucose, which are taken into cells through the glucose transporters. Conversely, the DG transport was not inhibited by AG at concentrations up to 50 mM. AG transport was hardly inhibited by 10 microM cytochalasin B, which strongly inhibits glucose transporters. In contrast, the AG transport was inhibited by 100 microM phloretin much more strongly than the DG transport when cells were preincubated with the inhibitor; the inhibition constant was 28.0 microM. The AG transport was not inhibited by 100 microM phloridzin, while the DG uptake was slightly inhibited by phloridzin. On the basis of these observations we propose that the AG uptake into rat hepatoma cells is mediated by a carrier distinct from glucose transporters.     

Transport of 1,5-anhydro-D-glucitol into human polymorphonuclear leukocytes.

1,5-Anhydro-D-glucitol (AG) is one of the main polyols and its structure resembles glucose. It has been proposed that decreased serum AG concentrations in diabetic patients are a novel indicator of diabetic metabolic derangement. However, the pathway of AG metabolism still remains to be clarified. In this study we investigated the transport of AG into human polymorphonuclear leukocytes (PMNLs) isolated from healthy volunteers and found that 0.1 mM 3-O-methy-D-glucose (3OMG) was equilibrated with a half saturation time of 10 s, while the uptake rate of AG was much slower. The concentration dependence of AG uptake revealed that the AG transport velocity reached a plateau, with a Km of about 50 mM and Vmax of about 25 nmol/min/10(7) cells. Transport of 14C-labeled 3OMG was inhibited by unlabeled D-glucose or AG in a dose-dependent manner. The mean inhibition constant (Ki) for D-glucose and for AG were 1.06 and 4.93 mM, respectively. Cytochalasin B (20 microM) inhibited 3OMG transport by 90% but AG transport by only 50%. S/V for 14C-labeled AG transport plotted against the concentration of unlabeled 3OMG showed a non-linear and biphasic pattern. These results suggest that AG influx into PMNLs is mediated not only by the cytochalasin B-sensitive glucose transport system but also via another facilitated transport system.     

Interactions of daidzin with intramolecular G-quadruplex

The potential interaction of daidzin, an ingredient of soy isoflavones, with human telomeric antiparallel G-quadruplex dAG(3)(T(2)AG(3))(3) was studied using ESI-MS, PAGE, CD and molecular simulation. Experimental studies indicated that daidzin molecules interacted with dAG(3)(T(2)AG(3))(3) and formed DNA-daidzin complex with the stoichiometric ratio of 1:1 and 1:2. The transition temperature of the G-quadruplex increased at higher ratio of daidzin to DNA. Under molecular crowding conditions the interactions between daidzin and the G-quadruplex become much stronger. Combining computational simulation and experimental results, it is demonstrated that the dAG(3)(T(2)AG(3))(3)/daidzin complex with a stoichiometric ratio of 1:1 is stabilized through the pi-pi conjugacy interactions and hydrogen bondings between daidzin and the bases of G-quadruplex. This work provides guidance not only on exploring the molecular anti-cancer mechanism of dietary isoflavones, but also searching small natural products as promising anticancer candidates that can inhibit telomerase activity.     

A spectroscopic study on the interactions of porphyrin with G-quadruplex DNAs

Free-base porphyrin (5,10,15,20-tetrakis(1-methyl-4-pyridyl)-21H,23H-porphine) (H(2)TMPyP4) has been shown to be an effective telomerase inhibitor by an in vitro assay. Here, we examined the interactions of the H(2)TMPyP4 with three distinct G-quadruplex DNAs, the parallel-stranded (TG(4)T)4, dimer-hairpin-folded (G(4)T(4)G(4))2, and monomer-folded AG(3)(T(2)AG(3))(3), by ultraviolet resonance Raman spectroscopy (UVRR), UV-vis absorption spectroscopy, fluorescence spectroscopy, and surface-enhanced Raman spectroscopy (SERS). The data obtained by the continuous variation titration method show that the binding stoichiometry of H(2)TMPyP4/G-quadruplex is 2:1 for (TG(4)T)4 and 4:1 for (G(4)T(4)G(4))2 or AG(3)(T(2)AG(3))(3). The results of SERS spectra, UV-vis absorption titration, and fluorescence emission spectra together with the binding stoichiometries reveal that two H(2)TMPyP4 molecules are externally stacked at two ends of the parallel (TG(4)T)4 G-quadruplex, whereas H(2)TMPyP4 molecules can intercalate within their diagonal or lateral loop regions and intervals between two G-tetrads for (G(4)T(4)G(4))2 and AG(3)(T(2)AG(3))(3) G-quadruplexes. The binding of H(2)TMPyP4 to (TG(4)T)4 G-quadruplex results in the hypochromicity of the UV Raman signal of (TG(4)T)4, indicating that the stacking effects between H(2)TMPyP4 and DNA bases are significant. The Raman hyperchromicities and shifts are observed after the binding of H(2)TMPyP4 to both (G(4)T(4)G(4))2 and AG(3)(T(2)AG(3))(3) G-quadruplexes. This indicates that the intercalative H(2)TMPyP4 can lengthen the vertical distance between adjacent G-tetrads of (G(4)T(4)G(4))2 and AG(3)(T(2)AG(3))(3) and change their conformations. The present study provides new insights into the effect of H(2)TMPyP4 binding on the structures of G-quadruplexes and also demonstrates that Raman spectroscopy is an ideal method for examining the interaction between drugs and G-quadruplexes.     

Anti-cataractogenic effect of curcumin and aminoguanidine against selenium-induced oxidative stress in the eye lens of Wistar rat pups: An in vitro study using isolated lens

The aim of this study was to investigate whether curcumin and aminoguanidine (AG) prevent selenium-induced cataractogenesis in vitro. On postpartum day 8, transparent isolated lens were incubated in 24 well plates containing Dulbecco's Modified Eagle Medium (DMEM). Isolated lens of group I were incubated with DMEM medium alone. Group II: lenses incubated in DMEM containing 100 μM sodium selenite; group III: lenses incubated in DMEM containing 100 μM sodium selenite and 100 μM curcumin; group IV: lenses incubated in DMEM containing 100 μM sodium selenite and 200 μM curcumin; group V: lenses incubated in DMEM containing 100 μM sodium selenite and 100 μM AG; group V: lenses incubated in DMEM containing 100 μM sodium selenite and 200 μM AG. On day 12, cataract development was graded using an inverted microscope and the lenses were analyzed for enzymic as well as non-enzymic antioxidants, lipid peroxidation (LPO), nitric oxide (NO), superoxide anion (O₂⁻) and hydroxyl radical generation (OH) and inducible nitric oxide synthase (iNOS) activity by Western blotting and RT-PCR. All control lenses in group I were clear (0). In groups II and III, all isolated lenses developed cataract with variation in levels (+++ or ++), whereas isolated lenses from groups IV, V and VI were clear (0). In agreement to this, a decrease in antioxidants and increased free radical generation and also iNOS expression were observed in selenium exposed lenses when compared to other groups. AG (100 μM) was found to be more effective in anti-cataractogenic effect than curcumin (200 μM). Curcumin and AG suppressed selenium-induced oxidative stress and cataract formation in isolated lens from Wistar rat pups, possibly by inhibiting depletion of enzymic as well as non-enzymic antioxidants, and preventing uncontrolled generation of free radicals and also by inhibiting iNOS expression. Our results implicate a major role for curcumin and AG in preventing cataractogenesis in selenite-exposed lenses, wherein AG was found to be more potent.     

Cross-links of quadruplex structures from human telomeric DNA by dinuclear platinum complexes show the flexibility of both structures

The folding of AG(3)(T(2)AG(3))(3) was investigated in the presence of Na(+) or K(+) ions, by using the dinuclear platinum complexes [{trans-PtCl(NH(3))(2)}(2)H(2)N(CH(2))(n)NH(2)]Cl(2) (n = 2 or 6). AG(3)(T(2)AG(3))(3) has been previously found to adopt two different quadruplex structures: the antiparallel one in a solution containing Na(+) and the parallel one in a K(+)-containing crystal. The two structures are strikingly distinct and are not expected to form the same platinum cross-links. Therefore, characterization of the cross-links formed with platinum complexes in solution allowed the predominant conformation(s) to be identified. The bases coordinating the platinum atoms were identified by chemical and 3'-exonuclease digestions. The observed cross-links showed that the parallel structure exists in solution whatever the cation and confirmed the existence of the antiparallel structure in the presence of both cations as previously reported from cross-linking experiments of AG(3)(T(2)AG(3))(3) by mononuclear platinum complexes. Furthermore, the major platinum cross-links were unexpectedly formed between two guanines belonging to the same G-quartet. Their formation was rationalized using molecular dynamics simulations in implicit solvent of the two quadruplex structures. It was shown that they were flexible, allowing some guanines to leave reversibly the top G-quartet and thus rendering their N(7) atom accessible to platinum complexes. Our results also suggest that the human telomere sequence could be a target for such platinum complexes.     

Hydrated Water Molecules of Pyrimidine/Purine/Pyrimidine DNA Triple Helices as Revealed by FT-IR Spectroscopy: A Role of Cytosine Methylation

Abstract

Hydrated water molecules of pyrimidine/purine/pyrimidine DNA hairpin triplex was studied by a comparison of triplex (CC·AG6) formed by a host oligodeoxypyrimidine of 5′- d(TC)₃T₄(CT)₃ (CC) with a target hexadeoxypurine 5′-d(AG)₃ (AG6) strand and by triplexes (MM·AG6, MC·AG6, and CM·AG6) formed by oligonucleotides with the exact sequences as above except 5-methylcytosine replaced all (MM), 5′ end half (MC), and 3′ end half (CM) cytosine bases in CC via FT-IR spectroscopy in hydrated film. Results revealed that: (i) all these triplexes have a similar hydration pattern, in which water molecules probably bound in the N₇ sites of adenines and guanines in the Crick-Hoogsteen groove, and to the methyl group of thymidines in the Watson-Hoogsteen groove. There are also some bound water molecules found at the O₂ sites of thymines in both Watson-Crick and Crick-Hoogsteen grooves, (ii) In the CC·AG6 triplex the S-type sugars are always dominant in all hydrated states, whereas in MM·AG6 triplex the relative population of the N-type sugars is very close to that of the S-type between 86% and 66% of humidity. Furthermore, the sugar conformation in two partially modified triplexes (CM·AG6, and MC·AG6) are dominant by the N-type at lower humidity. This phenomenon might reflect that the degree of bound water varies among the binding sites of bases, (iii) The effect of introducing a methyl group on cytosine is to generates spine of hydrophobic region in MM (MC and MC). The enlarging hydrophobic area not only increase the stability in solution, and also the stability in sodium hydrated films of the pyrimidine/purine/pyrimidine hairpin triplexes.     

大鼠肢体缺血/再灌注后肺损伤及一氧化氮合酶的变化与意义

目的：研究大鼠肢体缺血／再灌注后急性肺损伤时,内皮型一氧化氮合酶（eNOS）和诱导型一氧化氮合酶（i-NOS）的表达及其在急性肺损伤发生中的作用。方法：雄性Wistar大鼠于后肢根部阻断血流后松解（4h／4h）,分别给予L-Arg和氨基胍（AG）预先干预,分为control、IR、L-Arg和AG组,免疫组织化学方法检测肺组织中iNOS和eNOS的表达,同时检测肺组织中MDA、MPO、W／D和NO2^-／NO3^-值,肺组织形态学观察以评价肺损伤的程度。结果：与control组比较,I／R组eNOS表达降低,iNOS表达增强,MDA、MPO、W／D和NO2^-／NO3^-值增加。肺组织充血、炎细胞浸润,肺泡腔渗液;与I／R组比较,L-Arg组eNOS、iNOS表达无明显变化,NO2^-／NO3^-增加。MDA、MPO、W／D降低,肺组织损伤有减轻趋势,AG组eNOS表达无明显变化,iNOS活性降低,NO2^-／NO3^-减少,MDA、MPO、W／D增加,肺组织损伤有加重趋势。结论：肢体缺血／再灌注急性肺损伤过程中,iNOS表达增加,NO生成增多,在肺损伤发生中有一定的保护作用。     

Hsa-miR-499 rs3746444 Polymorphism Contributes to Cancer Risk: A Meta-Analysis of 12 Studies

Background

Single nucleotide polymorphisms (SNPs) occurred in pre-microRNAs or targets of microRNAs (miRs) may contribute to cancer risks. Since 2007, many studies have investigated the association between common SNPs located on hsa-miR-499 (rs3746444) and cancer risks; however, the results were inconclusive.

Methodology/Principal Findings

We conducted a meta-analysis of 12 studies that included 5765 cases and 7076 controls to identify the strength of association. Odds ratio (OR) and 95% confidence intervals (95% CI) were used to assess the strength of association. Overall, individuals with the variant AG (OR = 1.215, 95% CI: 1.027, 1.437; P_{heterogeneity}<0.01) and AG/GG (OR = 1.227, 95% CI: 1.046, 1.439; P_{heterogeneity}<0.01) genotypes were associated with a significantly increased risk of cancer than those with wild AA genotype. Sub-group analysis revealed that the variant AG (OR = 1.411, 95% CI: 1.142, 1.745; P_{heterogeneity} = 0.01) and AG/GG (OR = 1.413, 95% CI: 1.163, 1.717, P_{heterogeneity} = 0.01) genotypes still showed an increased risk of cancer in Asians; however, a trend of reduced risk of cancer was observed in Caucasians (AG vs. AA: OR = 0.948, 955 CI: 0.851, 1.057, P_{heterogeneity} = 0.12; AG/GG vs. AA: OR = 0.959, 95% CI: 0.865, 1.064; P_{heterogeneity} = 0.19). Meta-regression showed that ethnicity (p = 0.048) and sample size (p = 0.02) but not cancer types (p = 0.89) or source of control (p = 0.97) were the sources of heterogeneity.

Conclusions

These meta-analysis results suggest that hsa-miR-499 polymorphism rs3746444 is associated with a significantly increased risk of cancer, especially in Asian populations.     

Trials of direct detection and identification of <Emphasis Type="Italic">Rhizoctonia solani</Emphasis> AG 1 and AG 2 subgroups using specifically primed PCR analysis

Specifically primed polymerase chain reaction (PCR) analysis was used for direct detection and identification of Rhizoctonia solani isolates belonging to AG 1 subgroups (IA, IB, and IC) and AG 2 subgroups (2-1 and 2-2). A rapid DNA extraction method with a solution of sodium hydroxide was conducted to extract PCR templates. PCR-specific primer sets for each group were designed from sequences in the regions of the 28S ribosomal DNA of this fungus. The results of specifically primed PCR analysis showed that AG 1-IA, AG 1-IB, AG 1-IC, AG 2-1, and AG 2-2 primers sets contributed detection from the same AG isolates and could escape detection from different AG isolates at a high level of frequency. In this experiment, we suggested that our synthesized primer sets might provide a method for the direct detection and identification of AGs of R. solani. Received: June 28, 2001 / Accepted: November 14, 2001     

Molecular dissection of the AGAMOUS control region shows that cis elements for spatial regulation are located intragenically.

AGAMOUS (AG) is an Arabidopsis MADS box gene required for the normal development of the internal two whorls of the flower. AG RNA accumulates in distinct patterns early and late in flower development, and several genes have been identified as regulators of AG gene expression based on altered AG RNA accumulation in mutants. To understand AG regulatory circuits, we are now identifying cis regulatory domains by characterizing AG::beta-glucuronidase (GUS) gene fusions. These studies show that a normal AG::GUS staining pattern is conferred by a 9.8-kb region encompassing 6 kb of upstream sequences and 3.8 kb of intragenic sequences. Constructs lacking the 3.8-kb intragenic sequences confer a GUS staining pattern that deviates both spatially and temporally from normal AG expression. The GUS staining patterns in the mutants for the three negative regulators of AG, apetala2, leunig, and curly leaf, showed the predicted change of expression for the construct containing the intragenic sequences, but no significant change was observed for the constructs lacking this intragenic region. These results suggest that intragenic sequences are essential for AG regulation and that these intragenic sequences contain the ultimate target sites for at least some of the known regulatory molecules.     

The conserved dinucleotide AG of the 3′ splice site may be recognized twice during in vitro splicing of mammalian mRNA precursors

We have previously used site-directed mutagenesis to introduce an additional branch site into the first intron of the human β-globin gene at nt −24 between the natural branch site (nt−37) and the normal 3′ splice site (nt−1). We found that either the upstream or downstream branch site could be used during in vitro splicing, depending on which site best matched the mammalian branch site consensus YURAC (R = purine; Y = pyrimidine). Here we show that introduction of an additional AG dinucleotide at nt −20 between the downstream branch site and the normal 3′ splice site results in alternative 3′ splicing. Splicing to the new AG uses the upstream branch site exclusively, presumably because the downstream branch site is only 4 nt from this 3′ splice site. We were surprised, however, to find that the presence of the new AG also prevents the use of the upstream branch site for splicing to the normal 3′ splice site. Analysis of additional mutants confirmed earlier work [Krainer et al.: Mechanisms of human β-globin pre-mRNA splicing. In Berg, P. (Ed.), The Robert A. Welch Foundation Conferences on Chemical Research XXIX. Genetic Chemistry: The Molecular Basis of Heredity. Welch Foundation, Houston, TX, 1985, pp. 353–382] that the new AG cannot function by itself as a complete 3′ splice site; rather, it appears that alternative 3′ splicing initiates at the normal 3′ splices site but then searches, once the reaction is underway, for the first AG downstream from the chosen branch site. Taken together, our data suggest that the conserved AG dinucleotide at the 3′ splice site may be recognized twice during mammalian mRNA splicing in vitro.     

Effect of local sequence inversions on the crystalline antiparallel β-sheet lamellar structures of periodic polypeptides: implications for chain-folding

The crystal structure and texture of the monodisperse periodic polypeptide [(AG)₃EG(GA)₃EG]₁₀ (poly(±AG)₃EG; A=alanine, G=glycine, E=glutamic acid) were analyzed by X-ray diffraction, Fourier transform infrared spectroscopy, and electron microscopy. Structure determination was aided by comparison with the recently described structure for the related periodic polypeptide [(AG)₃EG]₃₆ by Krejchi et al. (Macromolecules 1997;30:5012). Texture-oriented samples of poly(±AG)₃EG were obtained by crystallization of the polymer from aqueous formic acid solution. The evidence supports an antiparallel (ap) β-sheet protein structure and the X-ray diffraction signals index on an orthorhombic unit cell with parameters: a=0.950 nm (hydrogen-bond direction), b=1.052 nm (apβ-sheet stacking direction), c=6.95 nm (chain direction). The absence of the (010) diffraction signal, a prominent signal in the poly(AG)₃EG diffraction pattern, implies that the apβ-sheets are ‘apolar', i.e. both surfaces are equally populated with alanyl methyl groups. Selective line broadening of wide-angle diffraction signals with ℓ≠0 gives an estimated crystal size of 4 nm in the chain direction. This observation, coupled with the appearance of low-angle particle interference peaks, indicates a crystal thickness considerably less than the chain length and suggests an adjacent-re-entry chain-folded lamellar structure incorporating the apβ-sheet architecture. The polypeptide folds through γ-turns, in-phase with the pseudo-octapeptide repeat; the glutamic acid residues occur on the lamellar surfaces. These results and those from the crystalline lamellae of poly(AG)₃EG suggest that β-turns are not compatible with these repetitively stacked apβ-sheet structures. This implies that intersheet interactions of alanyl methyl groups and glycyl -protons are not sufficiently strong to dictate the folding geometry in these structures.     

The inhibition of BDNF/TrkB/PI3K/Akt signal mediated by AG1601 promotes apoptosis in malignant glioma

Malignant glioma is the most aggressive primary brain tumor and has a poor survival rate. Even if extensive methods are preformed to treat glioma, the mortality rate is still very high. It is necessary for discovering and developing new drugs for malignant glioma treatment. AG1601 is one of AG-series drugs, including AG1031 and AG1503, and it has been optimized on the original basis. In our study, we found that AG1601 markedly inhibited proliferation and promoted C6 glioma cell apoptosis in vitro. AG1601 also reduced the size and weight of glioma in vivo. The growth ability of glioma was significantly inhibited after treatment with AG1601. It also showed that the expression levels of BDNF/TrkB/PI3K/Akt signal related proteins were obviously decreased in C6 glioma cells after treatment with AG1601 in vivo and in vitro. We also found that BDNF, as the activator of BDNF/TrkB/PI3K/Akt signal, reversed the anti-proliferation and pro-apoptosis of C6 glioma cells caused by AG1601. K252a, a specific inhibitor of TrkB, and AG1601 in combination aggravated C6 glioma cell apoptosis. These results indicate that AG1601 has good effects on the anti-proliferation and pro-apoptosis of malignant glioma via BDNF/TrkB/PI3K/Akt signal and could be considered as a potential drug in treating malignant glioma.