Preliminary Validation of Tumor Cell Attachment Inhibition Assay for Developmental Toxicants With Mouse S180 Cells

This study was designed to explore the possibility of using ascitic mouse sarcoma cell line (S180) to validate the mouse tumor cell attachment assay for developmental toxicants, and to test the inhibitory effects of various developmental toxicants. The results showed that 2 of 3 developmental toxicants under consideration, sodium pentobarbital and ethanol, significantly inhibited S180cells attachment to Concanavalin A-coaed surfaces. Inhibition was dependent on concentration, and the IC50 (the concentration tha reduced attachment by 50% ), of these 2 chemicals was 1.2×10-3mol/L and 1 .0 mol/L, respectively. Anoher developmental toxiant, hydmiortisone, did not show inhibitory activity. Two non-developmental toxicants, sodium chloride and glycine were also tested and these did not decrease attachment rates. The main results reported here were generally sindlar to those obtained with ascitic mouse ovdrian tumor cells as a model. Therefore, this study added further evidence to the conclusion that cell specificity does not lindt attachment inhibition to Con A-coated surfaces, so S180 cell may serve as an altemative cell model, especially when other cell lines are unavailable. Furthermore, after optimal validation, it can be suggested that an S180 cell attachment assay may be a candidate for a series of assays to detect developmental toxicants.

Green Tea Polyphenols Alleviate Autophagy Inhibition Induced by High Glucose in Endothelial Cells

Bovine aortic endothelial cells（BAECs）were cultured with high glucose（33 mmol/L）,4 mg/L green tea polyphenols（GTPs）or 4 mg/L GTPs co-treatment with high glucose for 24 h in the presence or absence of Bafilomycin-A1（BAF）.We observed that high glucose increased the accumulation of LC3-II.Treatment with BAF did not further increase the accumulation of LC3-II.

Effects of Different Doses of Doxorubicin on H9C2 Cells

Objective: To study the effect of different doses of doxorubicin on H9C2 cells and to provide a reference for the clinical study of doxorubicin. Methods: Doxorubicin (1, 2, 4, 6, 10 ug/ml) was co-cultured with H9C2 cells for 6, 12 and 24 hours. The morphological changes of cells were observed, and the cell inhibition rates of different time and drug concentration were calculated. Results: Doxorubicin could inhibit the activity of cardiomyocytes in a dose-dependent manner from 1 to 10 ug/ml. Conclusion: A certain dose of doxorubicin has a toxic effect on cardiomyocytes and can cause cardiomyocyte necrosis and apoptosis.

Effects of resveratrol on ARPE-19 cell proliferation and migration via regulating the expression of proliferating cell nuclear antigen, P21,P27 and p38MAPK/MMP-9

AIM： To explore whether resveratrol （Res） can inhibit human retinal pigment epithelial cell （ARPE-19 cell） proliferation and migration, and to research the molecular mechanisms.METHODS： ARPE-19 cells were pretreated with various concentrations at 0, 50, 100, 150, 200 and 300 μmol/L of Res, and with 0 μmol/L Res as the control for 24, 48 and 72h. The cell proliferation, apoptosis and migration were measured with cell counting kit-8 （CCK-8）, flow cytometry, and wound-healing and Transwell assays, respectively. The expression of proliferating cell nuclear antigen （PCNA）, P21 and P27, as well as matrix metalloproteinase-9 （MMP-9） and p38 mitogen-activated protein kinases （p38MAPK） was identified by Western blot.RESULTS： Cell proliferation was effectively inhibited by Res （P〈0.05）. When pretreated with Res, cells arrested in S-phase increased remarkably （P〈0.05）, but the apoptosis ratios showed no significant difference between the treatment and control groups （P〉0.05）. Cell migration was suppressed by Res both in wound-healing assay and Transwell migration assay （P〈0.05）. Decreases of PCNA, MMP-9 and p38MAPK, as well as increases of P21 and P27 were detected by Western blot （P〈0.05）. CONCLUSION： Res can inhibit APRE-19 cell proliferation and migration in a concentration-dependent manner with up-regulation of the expression of P21 and P27, and down-regulation of PCNA, MMP-9 and p38MAPK.

Multifactorial nature of hepatocellular carcinoma drug resistance: Could plant polyphenols be helpful?

Primary hepatocellular carcinoma （HCC） is a quite frequent tumor which results in high mortality and most often exhibits a poor response to present drug therapies. Clearly, a thorough understanding of the biological bases of this malignancy might suggest new strategies for its treatment. Here we examine the evidences that both ＂pharmacological＂ mechanisms （e.g. drug transporter or detoxification enzyme over-expression） and alterations in other critical factors, including the IAPs （Inhibitory of Apoptosis Proteins）, involved in enhancement of cell survival and proliferation may determine the therapeutic resistance of HCC; we also underline the possible role in the process of the activation of transcription factors, like NF-κB, capable of contemporaneously up-regulating the mechanisms discussed. On this basis, we finally comment on the possible use of natural multi-targeted antitumoral agents like plant polyphenols to achieve sensitization to treatments in HCC.

Inhibiting Smooth Muscle Cell Proliferation via Immobilization of Heparin/Fibronectin Complexes on Titanium Surfaces

The aim of this study was to investigate the inhibitory effect of heparin/fibronectin （Hep/Fn） complexes on neointimal hyperplasia following endovascular intervention. Hep/Fn complexes were immobilized onto titanium （Ti） surfaces, with subsequent X-ray photoelectron spectroscopy （XPS）, Toluidine Blue 0 （TBO） and immunohistochemistry methods were used to characterize surface properties. Smooth muscle cell （SMC） cultures were used to evaluate the effect of Hep/Fn complexes on SMC proliferation. Results showed that Hep/Fn complexes successfully immobilized onto Ti surfaces and resulted in an inhibition of SMC proliferation. This study suggests that Hep/Fn surface-immobilized biomaterials develop as a new generation of biomaterials to prevent neointimal hyperplasia, particularly for use in cardiovascular implants.

ANTI-CANCER EFFECT OF PSP PURIFIED PRODUCTS ON HUMAN TUMOR CELL LINES IN VITRO

The anti-cancer effect of PSP purified products, PSP-A, PSP-B, PSP-C and crude product PSP-Cr was compared on four human tumor cell lines in vitro. It was found that the inhibition rate of cell proliferation of PSP-A was higher than that of PSP-Cr (P<0. 05). On SPC cells, the inhibition rate of PSP-A at a dosage of 1000μg/ml was 62. 7%, being the highest as compared with those on the other three cell lines. Morphological changes were seen in all the four cell lines, especially in SPC cells after PSP-A treatment.

Cyclosporin A impairs dendritic cell migration by regulating chemokine receptor expression and inhibiting cyclooxygenase-2 expression

Migration of dendritic cells (DCs) into tissues and secondary lymphoid organs plays a crucial role in the initiation of innate and adaptive immunity. In this article, we show that cyclosporin A (CsA) impairs the migration of DCs both in vitro and in vivo. Exposure of DCs to clinical concentrations of CsA neither induces apoptosis nor alters development but does impair cytokine secretion, chemokine receptor expression, and migration. In vitro, CsA impairs the migration of mouse bone marrow-derived DCs toward macrophage inflammatory protein-3beta (MIP-3beta) and induces them to retain responsiveness to MIP-1alpha after lipopolysaccharide (LPS)-stimulated DC maturation, while in vivo administration of CsA inhibits the migration of DCs out of skin and into the secondary lymphoid organs. CsA impairs chemokine receptor and cyclooxygenase-2 (COX-2) expression normally triggered in LPS-stimulated DCs; administration of exogenous prostaglandin E2 (PGE2) reverses the effects of CsA on chemokine receptor expression and DC migration. Inhibition of nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinase (MAPK) pathway signaling by CsA may be responsible for the CsA-mediated effects on the regulation of chemokine receptor and cyclooxygenase-2 (COX-2) expression. Impairment of DC migration due to inhibition of PGE2 production and regulation of chemokine receptor expression may contribute, in part, to CsA-mediated immunosuppression.

Selective CDK inhibitors:promising candidates for future clinical traumatic brain injury trials

Traumatic brain injury induces secondary injury that contributes to neuroinflammation, neuronal loss, and neurological dysfunction. One important injury mechanism is cell cycle activation which causes neuronal apoptosis and glial activation. The neuroprotective effects of both non-selective （Flavopiridol） and selective （Roscovitine and CR-8） cyclin-dependent kinase inhibitors have been shown across mukiple experimental traumatic brain injury models and species. Cyclin-depen- dent kinaseinhibitors, administered as a single systemic dose up to 24 hours after traumatic brain injury, provide strong neuroprotection-reducing neuronal cell death, neuroinflammation and neurological dysfunction. Given their effectiveness and long therapeutic window, cyclin-dependent kinase inhibitors appear to be promising candidates for clinical traumatic brain injury trials.

Inhibition of vascular smooth muscle cell proliferation by in troduction of retinoblastoma gene via a recombinant adenovirus vector

This study was supported in part by grant from National Natural Science Foundation of China (No. 39570775). Objective To investigate the vascular smooth muscle cell (SMC) growth suppression by recombinant adenovirus vector expressing a retinoblastoma (Rb) protein and to explore a gene therapy approach for vascular proliferative disorders including atherosclerosis and artery restenosis. Methods A replication deficient adenovirus vector encoding a wild type Rb and AdCMVRb, was constructed and transfected into cultured rabbit aortic SMC. The efficiency of gene transfection and expression was detected by immunochemical staining and polymerase chain reaction. The role of Rb in regulating vascular SMC proliferation was observed by cell counting, thymidine incorporation, and flow cytometry. Results Wild type Rb gene transfected effectively into the cultured SMC with AdCMVRb can suppress growth factor stimulated cell proliferation through regulation of DNA synthesis and cell cycle progression. Conclusion The results demonstrate the potential of adenovirus mediated Rb gene therapy for atherosclerosis and artery restenosis after balloon angioplasty.

Changing roles of CD3^(+)CD8^(low) T cells in combating HIV-1 infection

Background:Cluster of differentiation 8(CD8 T)cells play critical roles in eradicating human immunodeficiency virus(HIV)-1 infection,but little is known about the effects of T cells expressing CD8 at low levels(CD8^(low))or high levels(CD8^(high))on HIV-1 replication inhibition after HIV-1 invasion into individual.Methods:Nineteen patients who had been acutely infected with HIV-1(AHI)and 20 patients with chronic infection(CHI)for≥2 years were enrolled in this study to investigate the dynamics of the quantity,activation,and immune responses of CD3^(+)CD8^(low) T cells and their counterpart CD3^(+)CD8^(high) T cells at different stages of HIV-1 infection.Results:Compared with healthy donors,CD3^(+)CD8^(low) T cells expanded in HIV-1-infected individuals at different stages of infection.As HIV-1 infection progressed,CD3^(+)CD8^(low) T cells gradually decreased.Simultaneously,CD3^(+)CD8^(high) T cells was significantly reduced in the first month of AHI and then increased gradually as HIV-1 infection progressed.The classical activation of CD3^(+)CD8^(low) T cells was highest in the first month of AHI and then reduced as HIV-1 infection progressed and entered the chronic stage.Meanwhile,activated CD38^(-)HLA-DR^(+)CD8^(low) T cells did not increase in the first month of AHI,and the number of these cells was inversely associated with viral load(r=-0.664,P=0.004)but positively associated with the CD4 T-cell count(r=0.586,P=0.014).Increased programmed cell death protein 1(PD-1)abundance on CD3^(+)CD8^(low) T cells was observed from the 1st month of AHI but did not continue to be enhanced,while a significant T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif(ITIM)domains(TIGIT)abundance increase was observed in the 12th month of infection.Furthermore,increased PD-1 and TIGIT abundance on CD3^(+)CD8^(low) T cells was associated with a low CD4 T-cell count(PD-1:r=-0.456,P=0.043;TIGIT:r=-0.488,P=0.029)in CHI.Nonetheless,the nonincrease in PD-1 expression on classically activated CD3^(+)CD8^(low) T cells was inversely associated with HIV-1 viremia in the first month of AHI(r=-0.578,P=0.015).Notably,in the first month of AHI,few CD3^(+)CD8^(low) T cells,but comparable amounts of CD3^(+)CD8^(high) T cells,responded to Gag peptides.Then,weaker HIV-1-specific T-cell responses were induced in CD3^(+)CD8^(low) T cells than CD3^(+)CD8^(high) T cells at the 3rd and 12th months of AHI and in CHI.Conclusions:Our findings suggest that CD3^(+)CD8^(low) T cells play an anti-HIV role in the first month of infection due to their abundance but induce a weak HIV-1-specific immune response.Subsequently,CD3^(+)CD8^(low) T-cell number decreased gradually as infection persisted,and their anti-HIV functions were inferior to those of CD3^(+)CD8^(high) T cells.

B7-H7 (HHLA2) inhibits T-cell activation and proliferation in the presence of TCR and CD28 signaling

Modulation of T-cell responses has played a key role in treating cancers and autoimmune diseases.Therefore,understanding how different receptors on T cells impact functional outcomes is crucial.The influence of B7-H7(HHLA2)and CD28H(TMIGD2)on T-cell activation remains controversial.Here we examined global transcriptomic changes in human T cells induced by B7-H7.Stimulation through TCR with OKT3 and B7-H7 resulted in modest fold changes in the expression of select genes;however,these fold changes were significantly lower than those induced by OKT3 and B7-1 stimulation.The transcriptional changes induced by OKT3 and B7-H7 were insufficient to provide functional stimulation as measured by evaluating T-cell proliferation and cytokine production.Interestingly,B7-H7 was coinhibitory when simultaneously combined with TCR and CD28 stimulation.This inhibitory activity was comparable to that observed with PD-L1.Finally,in physiological assays using T cells and APCs,blockade of B7-H7 enhanced T-cell activation and proliferation,demonstrating that this ligand acts as a break signal.Our work defines that the transcriptomic changes induced by B7-H7 are insufficient to support full costimulation with TCR signaling and,instead,B7-H7 inhibits T-cell activation and proliferation in the presence of TCR and CD28 signaling.

Selective elimination of host cells harboring replication-competent human immunodeficiency virus reservoirs:a promising therapeutic strategy for HIV cure

Many seminal advances have been made in human immunodeficiency virus(HIV)/AIDS research over the past four decades.Treatment strategies,such as gene therapy and immunotherapy,are yielding promising results to effectively control HIV infection.Despite this,a cure for HIV/AIDS is not envisioned in the near future.A recently published academic study has raised awareness regarding a promising alternative therapeutic option for HIV/AIDS,referred to as“selective elimination of host cells capable of producing HIV”(SECH).Similar to the“shock and kill strategy,”the SECH approach requires the simultaneous administration of drugs targeting key mechanisms in specific cells to efficiently eliminate HIV replication-competent cellular reservoirs.Herein,we comprehensively review the specific mechanisms targeted by the SECH strategy.Briefly,the suggested cocktail of drugs should contain(i)latency reversal agents to promote the latency reversal process in replication-competent reservoir cells,(ii)pro-apoptotic and anti-autophagy drugs to induce death of infected cells through various pathways,and finally(iii)drugs that eliminate new cycles of infection by prevention of HIV attachment to host cells,and by HIV integrase inhibitor drugs.Finally,we discuss three major challenges that are likely to restrict the application of the SECH strategy in HIV/AIDS patients.

Pure Total Flavonoids from Citrus paradisi Macfad InduceLeukemia Cell Apoptosis In Vitro

Objective： To investigate the potential effect of pure total flavonoids from Citrus paradisi Macfad peel（PTFC） on the proliferation and apoptosis of human myeloid leukemia cells Kasumi-1, HL-60 and K562, and the underlying mechanisms. Methods： PTFC was extracted from Citrus paradisi Macfad peel and was identified by high performance liquid chromatography. The effect of PTFC on the proliferation and apoptosis of leukemia cells were determined by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide, fluorescent microscopy and flow cytometry, respectively. The effect of PTFC on the expression levels of apoptosis-related regulators was determined by Western blot assay. Results： Treatment with PTFC inhibited leukemia cell proliferation in a dose-and time-dependent manner and triggered Kasumi-1 cell apoptosis. Treatment with PTFC significantly increased the levels of activated poly adenosine diphosphate-ribosepolymerase and caspase-3/-9, but reduced the levels of Mcl-1 expression in Kasumi-1 cells. However, PTFC did not obviously induce HL-60 cell apoptosis. Conclusion： PTFC inhibited leukemia cell proliferation and induced their apoptosis by modulating apoptosisrelated regulator expression in leukemia cells in vitro.

7,8-dihydroxyflavone protects human renal proximal tubular cells from hypoxia injury via inhibiting endoplasmic reticulum stress

Objective To observe the effects of 7,8-dihydroxyflavone(7,8-DHF)on hypoxia induced endoplasmic reticulum stress(ERS)in human proximal tubular epithelial cells(HK-2).Methods The mRNA level of ERS associated biomarkers was evaluated by RT-PCR assay

Targeted suppression of miRNA-21 inhibit K562 cells growth through PTEN-PI3K/AKT signaling pathway

Objective To investigate the K562 cells biological function and related molecular changes in PTEN-PI3K/AKT signaling pathway of leukemia K562 cells by inhibiting the miRNA-21 expression to explore its pathogenesis of leukemia.Methods The chemical synthetic miRNA-

Enhanced in vitro anticancer activity of quercetin mediated by functionalized CdTe QDs

We report in this study the effects of red-emitting CdTe QDs capped with cysteamine(Cys-CdTe) on the in vitro anticancer activity of the well-known flavenoid quercetin(Qu). Various techniques, including the methylthiazolyldiphenyl-tetrazolium bromide assay, the real-time cell electronic sensing system, the optical and fluorescence imaging, and electrochemical methods have been utilized to study the potential interactions of Cys-CdTe QDs with Qu. The observations demonstrate that the safe-dosage Cys-CdTe QDs can greatly improve the drug uptake and enhance the inhibition efficiency of Qu towards the proliferation of cancer cells such as HepG2 cells. This study implies that Cys-CdTe QDs may be used for cancer therapy and that they exert a synergic anticancer effect when bound to drug molecules.

Investigation of nuclear enzyme topoisomerase as a putative molecular target of monohaloacetonitrile disinfection by-products

Disinfection by-products occur widely as the unintended effect of water disinfection and are associated with toxicity and adverse human health effects. Yet the molecular mechanisms of their toxicity are not well understood. To investigate the molecular basis of hyperploidy induction by monohaloacetonitriles, the interaction of monohaloacetonitriles with topoisomerase Ⅱ in Chinese hamster ovary cells was examined. We showed a concentration-dependent inhibition of DNA decatenation activity of topoisomerase under acellular conditions while in vitro monohaloacetonitrile treatment expressed mixed results. The working hypothesis, that topoisomerase Ⅱ is a molecular target of monohaloacetonitriles, was only partially supported.Nevertheless, this research serves as a starting point toward molecular mechanisms of toxic action of monohaloacetonitriles.