[Molecular mechanisms of resistance to phosphatidyl inositol 3-kinase inhibitors in triple-negative breast cancer cells]

OBJECTIVE

To explore the molecular mechanisms of resistance to phosphatidyl inositol 3-kinase (PI3K) inhibitors in triple-negative breast cancer (TNBC) cells.

METHODS

HCC70 cells (TNBC) were transfected with siFZD7, siWANT5B or siGSK3 using lipofectamine 2000 transfection reagent. The expression levels of key proteins of WNT/β-catenin and PI3K/AKT/mTOR pathways were determined by Western blot analysis. After HCC70, MCF-7 (ER-positive) and SK-BR3 (HER2-positive) cells were treated with PI3K/AKT/mTOR inhibitors, the inhibition rates of cell proliferation were measured by MTT assay, and half maximal inhibitory concentrations (IC50) were calculated. The altered activities of WNT/β-catenin and PI3K/AKT/mTOR proteins were detected by Western blot and luciferase report gene assay, respectively. The nuclear translocation of β-catenin protein was examined by immunofluorescence assay. Xenograft nude mouse model was used to evaluate the tumorigenicity of breast cancer cells treated with BKM120 in vivo. The expression levels of p-LRP6, p-4EBP1 and β-catenin proteins in the tumor tissues were determined by immunohistochemical staining.

RESULTS

The expression levels of FZD7, WANT5B and GSK3 proteins were significantly reduced in the HCC70 cells transfected with the target siRNAs. Meanwhile, the activity of WNT/β-catenin was enhanced and PI3K/AKT/mTOR pathway was inhibited. PI3K/AKT/mTOR inhibitors suppressed MCF-7 and SK-BR3 cell proliferation. The IC50 of GDC-094, BKM120, XL147, perifosine, everolimus, and BEZ235 in MCF-7 cells were 0.46 mmol/L, 1.44 mmol/L, 4.34 mmol/L, 11.35 μmol/L, 53.71 μmol/L and 12.87 μmol/L respectively, and 0.63 mmol/L, 0.58 mmol/L, 3.74 mmol/L, 13.22 μmol/L, 60.00 μmol/L and 11.38 μmol/L in the SK-BR3 cells, respectively. The results of luciferase report gene assay showed that the luciferase activities in HCC70, MCF-7 and SK-BR3 cells treated with BKM120 were 1.75±0.05, 1.13±0.02 and 0.43±0.01, respectively. The luciferase activities in HCC70 and SK-BR3 cells were significantly different from that of the control cells (1.00±0.02, P<0.05). The immunohistochemical analysis showed that BKM120 inhibited mTOR activity, and the enhanced WNT/β-catenin activity reversed the phenotype of inhibitory mTOR induced by BKM120. BKM120 suppressed the tumorigenic ability of MCF-7 and SK-BR3 cells in vivo, but had no effect on cultured HCC70 cells. The immunohistochemical analysis showed nuclear translocation of β-catenin protein and increased expression level of p-LRP-6 protein in transplanted tumor tissues from HCC70 cells treated with BKM120, increased the level of p-LRP-6 protein, and no changes of p-4EBP1 protein expression. However, no nuclear translocation of β-catenin protein and no decrease of p-LRP6 and p-4EBP1 protein levels in the transplanted tumor tissue of MCF-7 cells after treatment with BKM120.

CONCLUSIONS

The triple-negative breast cancer HCC70 cells have drugs-resistance to PI3K inhibitors. The WNT/β-catenin signaling pathway may regulate the PI3K/AKT/mTOR pathway, therefore, inducing the drug-resistance of TNBC cells to PI3K inhibitors.

Neuroprotective effects of Bcl-2 overexpression on nerve cells of rats with acute cerebral infarction

We aimed to investigate the influence of lentiviral-mediated Bcl-2 overexpression in cerebral tissues of rats with acute cerebral infarction. Forty-five rats were randomly divided into sham, model, and treatment groups. The sham and model groups were administered a control lentiviral vector via the intracranial arteries 10 days before surgery, while the treatment group received lentivirus encoding a Bcl-2 overexpression vector. We induced cerebral artery infarction using a suture-occlusion method and analyzed the cerebral expression levels of apoptosis-related genes (caspase-3, Bax), total cerebral apoptosis, range of cerebral tissue infarction, and changes in nerve cell function after 72 h. The Bcl-2-encoding lentivirus was well expressed in rat cerebral tissues. The treatment group had significantly higher expression levels of Bcl-2 than the other two groups. After cerebral infarction, the model group had significantly increased expression levels of caspase-3 and Bax protein in cerebral tissues than the sham (P < 0.05). Expression of these apoptosis-related proteins in the treatment group was obviously lower than that in the model group (P < 0.05), but significantly higher than in the sham group (P < 0.05). Compared to sham, neuronal apoptosis levels and infarction range of cerebral tissues was increased in the model and treatment groups; however, these values in the treatment group were significantly lower than that in the model group (P < 0.05). Importantly, the treatment group had significantly decreased neurological impairment scores (P < 0.05). In conclusion, Bcl-2 over-expression can decrease neuronal apoptosis in rat cerebral tissue, and thus is neuroprotective after cerebral ischemia.

Evaluating the possibility of using acetone-butanol-ethanol (ABE) fermentation wastewater for bacterial cellulose production by Gluconacetobacter xylinus

To reduce the cost of bacterial cellulose (BC) production, the possibility of using acetone-butanol-ethanol (ABE) fermentation wastewater with high COD value (18 050 mg l(-1) ) for BC production by Gluconacetobacter xylinus was evaluated. After 7 days of fermentation, the highest BC yield (1·34 g l(-1) ) was obtained. The carbon sources including sugars (glucose and xylose), organic acids (acetic acid and butyric acid) and alcohol compounds (ethanol and butanol) were utilized by G. xylinus simultaneously during fermentation. Although the COD decrease ratio (about 14·7%) was low, the highest BC yield on COD consumption (56·2%, g g(-1) ) was relatively high and the remaining wastewater could be used for further BC fermentation. Besides, the environment of ABE fermentation wastewater showed small influence on the BC structure by comparison with the BC products obtained in traditional HS medium using field emission scanning electron microscope (FE-SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Overall, ABE fermentation wastewater is one promising substrate for BC production.

SIGNIFICANCE AND IMPACT OF THE STUDY

The possibility of using acetone-butanol-ethanol (ABE) fermentation wastewater for bacterial cellulose (BC) production by Gluconacetobacter xylinus was evaluated in this study. This is the first time that ABE fermentation wastewater was used as substrate for BC fermentation. The results provide detail information of metabolism of G. xylinus in ABE fermentation wastewater and the influence of wastewater environment on the structure of BC samples. Overall, this bioconversion could reduce the cost of BC production greatly.

Molecular cloning and functional characterization of a novel CBL-interacting protein kinase NtCIPK2 in the halophyte Nitraria tangutorum

CBL-interacting protein kinases (CIPKs) mediate many plant responses to abiotic stress. However, their functions are poorly understood in halophytes. In this study, we isolated a CIPK gene, NtCIPK2, from the halophyte Nitraria tangutorum. By sequence alignment and the construction of a phylogenetic tree, we found that NtCIPK2 is similar to CIPK2 proteins from other plants, and contains conserved domains and motifs. The promoter of NtCIPK2 harbors many cis-acting elements that might be recognized and bound by transcription factors that are related to hormones and stress responses. NtCIPK2 was ubiquitously and robustly expressed in all tested organs, and was induced by salinity, drought, heat, and cold stress. The overexpression of NtCIPK2 in Escherichia coli caused better growth against high salinity, alkalinity, and osmotic conditions, dehydration, and extreme temperatures (i.e., heat and cold) compared to the control. Thus, NtCIPK2 is a candidate gene that might improve the stress tolerance of crops and herbs through genetic manipulation.

Bioconversion of elephant grass (Pennisetum purpureum) acid hydrolysate to bacterial cellulose by Gluconacetobacter xylinus

AIMS

To evaluate the possibility of elephant grass acid hydrolysate converting into bacterial cellulose (BC) produced by Gluconacetobacter xylinus CH001 and to characterize the morphology and structure of the cellulose produced.

METHODS AND RESULTS

Acid-hydrolysed and detoxified elephant grass acid hydrolysate was inoculated with G. xylinus CH001. After 14 days of static fermentation, about 6·4 g l(-1) of BC could be generated. Meanwhile, 60·4% (w/w) of BC yield on sugar consumption was obtained. Scanning electron micrographs illustrated that the network of cellulose fibres became denser, and the diameter changed with the growth. FT-IR spectra showed almost same results for all the BC samples collected on different culture time. X-ray diffractograms demonstrated that the crystalline form of BC was cellulose I, the crystallinity increased to 53·58%, and the crystallinity index reached up to 99%.

CONCLUSIONS

Elephant grass acid hydrolysate could be utilized efficiently for BC production by G. xylinus CH001. Structure analysis on the cellulose produced showed its potential of being excellent material for further application.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our studies for the first time examined the bioconversion of low-cost elephant grass into high-value BC and the changes in its morphology and structure following the culture time.

Generating mechanism for higher-order rogue waves

We introduce a mechanism for generating higher-order rogue waves (HRWs) of the nonlinear Schrödinger (NLS) equation: the progressive fusion and fission of n degenerate breathers associated with a critical eigenvalue λ(0) creates an order-n HRW. By adjusting the relative phase of the breathers in the interacting area, it is possible to obtain different types of HRWs. The value λ(0) is a zero point of an eigenfunction of the Lax pair of the NLS equation and it corresponds to the limit of the period of the breather tending to infinity. By employing this mechanism we prove two conjectures regarding the total number of peaks, as well as a decomposition rule in the circular pattern of an order-n HRW.

Structural properties and charge ordered states in RMnO3 (R=La, Pr, Nd, Ca, Sr) and (La, Sr)2NiO4

Structural distortions arising from the condensations of two essential kinds of phonon modes: the triply degenerate rotational modes (phix, phiy, phiz) of MnO(6) and the doubly degenerate Jahn-Teller active modes (Q1, Q2) have been systematically investigated in the perovskite manganites. Microstructural features associated with certain types of distortions have been observed by transmission electron microscopy (TEM). In RMnO(3) and La(Sr)(2)NiO(4), we characterize the local structure, charge ordered states and orbital ordering by means of low-temperature TEM. We present direct evidence that the stripe modulation in La(Sr)(2)NiO(4) is indeed one-dimensional within each NiO(2) plane. Several typical kinds of defect structures, including antiphase boundaries and the 90 degrees -twin domains, appear commonly in the charge-ordered states.

[Study on the interaction between sparfloxacin and serum albumins by fluorescence]

The binding reaction between sparfloxacion (SPFX) and bovine serum albumin (BSA) or chicken egg albumin (CEA) in aqueous was studied using fluorescence and absorption spectra. Their binding constants are KCEA = 8.29 x 10(6) and KBSA = 4.41 x 10(7), and the binding sites are nCEA = 0.558, nBSA = 0.793 respectively. The action distances (RCEA = 1.99 nm, RBSA = 2.09 nm) and energy transfer efficiencies (ECEA = 0.766, EBSA = 0.714) between donor-acceptor and SPFX were obtained by Förster's nonradiative energy transfer mechanism. The experiment demonstrated that the higher the temperature is, the lower the slopes of quenching curves of BSA and CEA are in presence of different amounts of SPFX. It is confirmed that the combination for SPFX with BSA or CEA is a single static quenching process, their interaction may be interpreted with energy transfer mechanism. Through binding reaction of the two albumins with SPFX, the biological effects and action mechanism of SPFX with albumins in vivo were discussed.

Biradicals from benzoenyne-allenes. Application in the synthesis of 11H-benzo[b]fluoren-11-ols, 1H-cyclobut[a]indenes, and related compounds

New synthetic pathways to 11H-benzo[b]fluoren-11-ols, 1H-cyclobut[a]indenes, and related compounds via biradicals generated from benzoenyne-allenes were developed. Treatment of the diacetylenic propargylic alcohols 13, derived from condensation between benzophenones and the lithium acetylide of 1-(2-ethynylphenyl)-2-phenylethyne, with thionyl chloride produced the 11-chloro-11H-benzo[b]fluorene 14 and, after hydrolysis, the corresponding 11H-benzo[b]fluoren-11-ols 15. The transformation involved a sequence of reactions, including a biradical-forming C2-C6 cyclization (Schmittel cyclization) reaction of the chlorinated benzoenyne-allene intermediates followed by an intramolecular radical-radical coupling to form the formal Diels-Alder adducts. Interestingly, in the case of the diacetylenic propargylic alcohol 26, obtained from dibenzosuberenone (25), an intramolecular [2 + 2] cycloaddition reaction of the chlorinated benzoenyne-allene intermediate occurred, furnishing the 1H-cyclobut[a]indene 27 exclusively. The dramatic change of the reaction pathway could be attributed to the emergence of a steric strain due to the nonbonded interactions with the chloro substituent along the pathway toward the formal Diels-Alder adduct 31. On the other hand, the non-chlorinated benzoenyne-allene, derived from prototropic isomerization of the diacetylenic hydrocarbon 60, underwent a formal Diels-Alder reaction to furnish the 11H-benzo[b]fluorene-type hydrocarbon 61 exclusively.

Synthesis of 6H-indolo[2,3-b][1,6]naphthyridines and related compounds as the 5-Aza analogues of ellipticine alkaloids

Treatment of 2-(1-alkynyl)phenyl isocyanates 6 with the iminophosphorane 14 produced in situ the benzoenynyl carbodiimides 15. Thermolysis of 15 under refluxing p-xylene furnished the 6H-indolo[2,3-b][1,6]naphthyridines 5, which could be regarded as the 5-aza analogues of ellipticine alkaloids. Similarly, condensation of 6 with the iminophosphorane 20 led to the formation of the 6H-indolo[2,3-b][1,5]naphthyridines 25 as the major isomer and the 10H- indolo[2,3-b][1,7]naphthyridines 26 as the minor isomer. The indolonaphthyridines 32, 33, and 34 having a methoxyl substituent were likewise synthesized. Treatment of the diisocyanate 43 with 2 equiv of the iminophosphorane 7 furnished 45 having two indoloquinoline units incorporated in a seven-fused-ring system.

[Bioconversion of hemicellulose hydrolysates for xylitol production]

Xylitol has attracted much attention because of its many applications in the food, medicine and chemical industries. However the use has been limited by its high price. This coast is a result of the extensive purification steps needed for the preparation of a pure xylose solution, which is essential for the chemical process. The fermentative process of xylitol is an interesting alternative to conventional chemical process, since it does not require initial xylose purification. The present review describes the advantage of xylitol production by fermentation, xylitol-producting microorganisms, metabolic pathway of xylose in yeasts, detoxification of hemicellulose hydrolysates and fermentative conditions affecting xylitol production.

[A study on histopathology of iris with Nd: YAG and/or argon laser iridotomy]

Laser iridotomy including Nd: YAG, argon and Nd: YAG combined with argon was performed on 42 eyes of 25 chinchilla rabbits. The postoperative follow-up was 8 months. The histopathological changes of the irides at the sites of the various laser shots under light, transmission and scanning electron microscopic examinations were compared. The results show: (1) In regard to the Nd: YAG laser effect on the target tissue, the inherent elasticity of the tissue may play a more important role in curative effects of the therapy than the thickness of the tissue. (2) Every iris hole, < 200 microns in diameter, performed by Nd: YAG or < 450 microns, by argon or argon combined with Nd: YAG was closed by the first postoperative week. The histopathological findings demonstrate that the pigment epithelial proliferation and migration are more marked in the irides with argon laser iridotomy. (3) An insufficient coagulative burn of the argon laser may cause congestion of iris blood vessels and possibly, result in more severe bleeding during succedent Nd: YAG laser shots.

[Photogenic retinal damage and its medicinal prevention: lipid peroxide studies]

Continuous illumination of 18,175 lx caused degeneration of the retinal photoreceptor cells in albino rats, accompanied by increase of malondialdehyde (MDA) 3 days after the light exposure. The MDA decreased gradually to return to normal 8 days after the exposure. Administration of vitamin E or beta-carotine both prevented the increase of retinal lipid peroxide with amelioration of the photic injury to the retinal structures, though the effects were closely related to the dosage and time of medication.

[Prophylactic and therapeutic effect of jiawei zhigancao tang injection on experimental arrhythmia in rats]

The antiarrhythmic effect of Jiawei Zhigancao Tang injection (JZTI) was studied in experimental arrhythmia induced by aconitine or by CaCl2 in anesthetized rats. The prophylactic dose of JZTI (5g/kg, i.v.) reduced the incidence rate of premature ventricular complexes, ventricular tachycardia (P < 0.01), delayed the onset time of arrhythmia induced by CaCl2 (P < 0.01), and the recovery time of sinus rhythm occurred earlier than that of control group (P < 0.01). The therapeutic dose of JZTI (10g/kg, i.v.) raised the rate of aconitine-induced arrhythmia to sinus rhythm conversion (P < 0.05). The results showed that JZTI could significantly antagonize arrhythmia induced by aconitine or by Cacl2 in rats.

[Quantitative study of diabetic retinopathy by computerized image analysis]

Composite fluorescein angiographic pictures of 66 eyes with diabetic retinopathy and nonperfusion areas were studied by computerized image analysis, and the ratio of the nonperfusion area to the disc area was calculated. There were 49 eyes with neovascularization (NV), in which the mean ratio +/- standard error was 46.33 +/- 7.01 (8.15 to 298.26), and the corresponding value in the other 17 eyes without NV was 6.90 +/- 1.31 (2.20 to 21.37), the difference being very significant. When the ratios were under 10, from 10 to 30, or over 30, the percentages of eyes manifesting NV were 13.3%, 81.8% and 100% respectively. In the 49 eyes with NV, the majority of the total 267 neovascular clusters were distributed 4-6 DD away from the optic disc, which itself was involved only in 18 eyes.

[Determination of retinal illumination from operating microscopes and assessment of risk]

The retinal illumination from 5 popular operating microscopes was determined with the authors' method to reveal that the intensity of light differed very significantly between brightness adjustments. With dilated pupil and clear media, the power of illumination on the retina was 0.072-0.233 W/cm2 at maximum brightness and 0.042-0.084 W/cm2 at medium brightness, and the safety time limits for application were 22.49s for the former and 50.38s for the latter to avoid retinal damages.

[Quantitative computerized image analysis of the relationship between neovascularization and nonperfusion area in branch retinal vein occlusion]

Quantitative computerized image analysis of composite fluorescein angiograms of 62 eyes with branch retinal vein occlusion (BRVO) found 33 eyes with newly formed blood vessels. Determination of the ratio of the retinal capillary nonperfusion area to the disk area revealed that the ratio was positively correlated with the incidence of neovascularization, in that 10.0% of the cases with the ratio under 10 and 63.2% of the cases with the ratio between 10-30 had neovascularization, and the incidence of the latter increased to 82.6% among cases with the ratio over 30. The calibres of 344 retinal arteries and veins in normal subjects and in the affected and unaffected eyes of BRVO patients were measured to find that both vessels were narrowed in late patients of retinal vein occlusion.

[Risk factors and visual prognosis of 407 patients with retinal vein occlusion]

Among 407 patients (416 eyes) with retinal vein occlusion (RVO), 196 eyes had branch RVO, 185 eyes central RVO, and 26 eyes hemi-central RVO. The ischemic type accounted for 39.7%, and the non-ischemic type 60.3%. The risk factors were vascular hypertension (59.8%), retinal arteriosclerosis (58.0%), increased blood beta-lipoprotein (49.0%) and fibrinogen (21.7%), and high blood viscosity. The mean levels of whole blood and plasma viscosity were significantly higher in the patients than in the controls. The therapeutic effective rate was 63.2% for branch RVO, 52.4% for central RVO, and 69.2% for hemicentral RVO. The resultant rate of blindness was 15.9%, and that of low vision 23.1%, due to cystoid macular edema (44.4%) and vitreous hemorrhage (15.4%). The incidence of neovascular glaucoma was 9.5% in central RVO.

[Idiopathic macular preretinal membrane in the elderly]

Idiopathic macular preretinal membrane was diagnosed in 14 patients, 4 males and 10 females, with age ranging from 47-72 years (mean 59.1 yrs) and a follow-up period from 1 month to 9 years (mean 2 yrs). The initial visual acuity varied from 0.05-1.5. Ophthalmoscopy and fluorescein angiography demonstrated fundus glinting light reflex, retinal fold, macular whitish preretinal membrane, distortion of the retinal vessels, and occasional microaneurysms and lamellar macular hole. The etiology was unknown. Progress of the disease was slow. Vision deteriorated in only 2 cases, and in 11 cases it remained stable for years.

[The segmental characteristic of the human choroidal vessels and its clinical significance]

The segmental vascular supply and anastomosis of human choroidal vessels were studied in 10 subjects (20 eyes) by the corrosion cast technique and scanning electron microscopy. The distribution pattern of the choroidal vessels was characterized by distinct segmental arrangement of large vessels and lobular arrangement of choriocapillaries. Maximal choriocapillary density and caliber were observed in the posterior pole. The mean diameters of the choriocapillaries in the macular, the equatorial, and the peripheral areas were 25.19 + 0.99 microns, 22.42 + 1.07 microns, and 28.1 + 1.29 microns respectively. It was also revealed that interarterial anastomosis existed among large arteries, precapillary arterioles, and even choriocapillaries. Veno-venous anastomotic communications were a general phenomenon. Therefore, the choroidal vessels are not true end-arteries anatomically. Obstructions at different levels of the choroidal arteries show corresponding clinical features. Occlusion in a posterior ciliary artery or a large choroidal artery is known as the triangular syndrome. Choriocapillary obstruction can be caused by many diseases. The relationship between the RPE and the choriocapillaries was discussed.

[Electron microscopy of the angioarchitecture of the human iris and ciliary body]

With the corrosion cast technique and electron microscopy, the major arterial circle of the iris, formed by the terminal branches of the medial and lateral long posterior ciliary arteries and of the anterior ciliary arteries, is shown not an anastomosed vascular ring but divided small branches of the arteries to supply the iris and ciliary body. The iris vessels demonstrate a radiate distribution of about 180-200 branches. The calibres of the iris arteries are homogeneous and measure about 50-120 microns. The branching portion of a precapillary arteriole begins with a constriction. The vessels of the ciliary processes account for more than half the volume of the ciliary body and have a rich capillary network of at least two layers. The draining veins are located on the surface and at the base of the ciliary body. There are 7-10 draining veins between two ciliary processes.

Extracapsular cataract extraction: prognosis and complications with and without posterior-chamber lens implantations

Four-hundred-and-sixteen eyes that underwent cataract extraction over six years were analyzed. Extracapsular cataract extraction with posterior-chamber intraocular lens implantation (PCIOL) was performed in 186 eyes and extracapsular cataract extraction (ECCE) alone was performed in 230 eyes. The complications and visual acuity were compared in the two groups. The PCIOL group showed a low incidence of postoperative complications. In addition, there were no cases of corneal edema; retinal detachment occurred in 1.33%; cystoid macular edema occurred in 2.67%; and visual acuity recovered to 20/40 or better in 96.67% of eyes. The incidence of complications in the ECCE group was slightly higher.