Paxilline enhances TRAIL-mediated apoptosis of glioma cells via modulation of c-FLIP, survivin and DR5

Tumor necrosis factor-related apoptosis-induced ligand (TRAIL) induces apoptosis selectively in cancer cells while sparing normal cells. However, many cancer cells are resistant to TRAIL-induced cell death. Here, we report that paxilline, an indole alkaloid from Penicillium paxilli, can sensitize various glioma cells to TRAIL-mediated apoptosis. While treatment with TRAIL alone caused partial processing of caspase-3 to its p20 intermediate in TRAIL-resistant glioma cell lines, co-treatment with TRAIL and subtoxic doses of paxilline caused complete processing of caspase-3 into its active subunits. Paxilline treatment markedly upregulated DR5, a receptor of TRAIL, through a CHOP/GADD153-mediated process. In addition, paxilline treatment markedly downregulated the protein levels of the short form of the cellular FLICE-inhibitory protein (c-FLIPs) and the caspase inhibitor, survivin, through proteasome-mediated degradation. Taken together, these results show that paxilline effectively sensitizes glioma cells to TRAIL-mediated apoptosis by modulating multiple components of the death receptor-mediated apoptotic pathway. Interestingly, paxilline/TRAIL co-treatment did not induce apoptosis in normal astrocytes, nor did it affect the protein levels of CHOP, DR5 or survivin in these cells. Thus, combined treatment regimens involving paxilline and TRAIL may offer an attractive strategy for safely treating resistant gliomas.     

Human hepatocellular carcinoma cells resist to TRAIL-induced apoptosis,and the resistance is abolished by cisplatin

TNF-related apoptosis-inducing ligand (TRAIL), a member of the TNF family, selectively induce apoptosis in various transformed cell lines but not in almost-normal tissues. It is regulated by 2 death receptors, TRAIL receptor 1 (TRAIL-R1) and TRAIL-R2 and 2 decoy receptors, TRAIL-R3 and TRAIL-R4. However, the determining factors of the sensitivity to TRAIL-induced apoptosis are not clearly understood. Herein, we investigated the expression of TRAIL-R, c-FLIP, FADD-like interleukin-1beta-converting enzyme inhibitory protein, and TRAIL-induced apoptosis in human hepatocellular carcinoma (HCC) cell lines. Seven of ten HCC cell lines showed resistance to TRAIL-induced apoptosis and five of seven TRAIL-resistant cell lines became sensitive to TRAIL by co-treatment with cycloheximide. In HCC cell lines, their TRAIL resistance did not correlate with the basal expression level of TRAIL receptors or c-FLIP, however, in human tissues, TRAIL-R1 and TRAIL-R2 expressions were notably decreased compared to normal counterpart. Cisplatin showed synergistic effect on TRAIL-induced apoptosis in most HCC cell lines regardless of their p53 status and TRAIL-R1 was induced by cisplatin treatment in certain cell lines. Inhibition of nuclear factor K B (NF-kappaB) by SN50, a peptide inhibitor of NF-KB activity, had no effect on TRAIL-induced apoptosis in HCC cells. These results suggest that (a) the majority of human HCC cell lines are resistant to TRAIL-induced apoptosis and cycloheximide-sensitive short-lived antiapoptotic molecule(s) is responsible for this resistance, (b) the expression of TRAIL-R1 and TRAIL-R2 is reduced in HCC tissues, and the increased expression of TRAIL-R1 may be a mechanism of cisplatininduced sensitization to TRAIL-induced apoptosis in some HCC cells, and (c) the activation of NF-kappaB may not be involved in the TRAIL resistance of HCC cells     

Iron(II)−Polypyridyl Complexes Inhibit the Growth of Glioblastoma Tumor and Enhance TRAIL‐Induced Cell Apoptosis

A promising cancer‐targeting agent for the induction of apoptosis in tumor necrosis factor (TNF) proteins, the TNF‐related apoptosis‐inducing ligand (TRAIL) ligand, has found limited applications in the treatment of cancer cells, owing to its resistance by cancer cell lines. Therefore, the rational design of anticancer agents that could sensitize cancer cells towards TRAIL is of great significance. Herein, we report that synthetic iron(II)−polypyridyl complexes are capable of inhibiting the proliferation of glioblastoma cancer cells and efficiently enhancing TRAIL‐induced cell apoptosis. Mechanistic studies demonstrated that the synthesized complexes induced cancer‐cell apoptosis through triggering the activation of p38 and p53 and inhibiting the activation of ERK. Moreover, uPA and MMP‐2/MMP‐9, among the most important metastatic regulatory proteins, were also found to be significantly alerted after the treatment. Furthermore, we also found that tumor growth in nude mice was significantly inhibited by iron complex Fe2 through the induction of apoptosis without clear systematic toxicity, as indicated by histological analysis. Taken together, this study provides evidence for the further development of metal‐based anticancer agents and chemosensitizers of TRAIL for the treatment of human glioblastoma cancer cells.     

Kurarinone promotes TRAIL-induced apoptosis by inhibiting NF-��B-dependent cFLIP expression in HeLa cells

This study was designed to investigate the effects of the prenylated flavonoid kurarinone on TNF-related apoptosis inducing ligand (TRAIL)-induced apoptosis and its underlying mechanism. A low dose of kurarinone had no significant effect on apoptosis, but this compound markedly promoted tumor cell death through elevation of Bid cleavage, cytochrome c release and caspase activation in HeLa cells treated with TRAIL. Caspase inhibitors inhibited kurarinone-mediated cell death, which indicates that the cytotoxic effect of this compound is mediated by caspase-dependent apoptosis. The cytotoxic effect of kurarinone was not associated with expression levels of Bcl-2 and IAP family proteins, such as Bcl-2, Bcl-x_L, Bid, Bad, Bax, XIAP, cIAP-1 and cIAP-2. In addition, this compound did not regulate the death-inducing receptors DR4 and DR5. On the other hand, kurarinone significantly inhibited TRAIL-induced IKK activation, IκB degradation and nuclear translocation of NF-κB, as well as effectively suppressed cellular FLICE-inhibitory protein long form (cFLIP_L) expression. The synergistic effects of kurarinone on TRAIL-induced apoptosis were mimicked when kurarinone was replaced by the NF-κB inhibitor withaferin A or following siRNA-mediated knockdown of cFLIP_L. Moreover, cFLIP overexpression effectively antagonized kurarinone-mediated TRAIL sensitization. These data suggest that kurarinone sensitizes TRAIL-induced tumor cell apoptosis via suppression of NF-κB-dependent cFLIP expression, indicating that this compound can be used as an anti-tumor agent in combination with TRAIL.     

Tunicamycin enhances TRAIL-induced apoptosis by inhibition of cyclin D1 and the subsequent downregulation of survivin

TNF-related apoptosis-inducing ligand (TRAIL) has been proposed as a promising cancer therapy that preferentially induces apoptosis in cancer cells, but not most normal tissues. However, many cancers are resistant to TRAIL by mechanisms that are poorly understood. In this study, we showed that tunicamycin, a naturally occurring antibiotic, was a potent enhancer of TRAIL-induced apoptosis through downregulation of survivin. The tunicamycin-mediated sensitization to TRAIL was efficiently reduced by forced expression of survivin, suggesting that the sensitization was mediated at least in part through inhibition of survivin expression. Tunicamycin also repressed expression of cyclin D1, a cell cycle regulator commonly overexpressed in thyroid carcinoma. Furthermore, silencing cyclin D1 by RNA interference reduced survivin expression and sensitized thyroid cancer cells to TRAIL; in contrast, forced expression of cyclin D1 attenuated tunicamycin-potentiated TRAIL-induced apoptosis via over-riding downregulation of survivin. Collectively, our results demonstrated that tunicamycin promoted TRAIL-induced apoptosis, at least in part, by inhibiting the expression of cyclin D1 and subsequent survivin. Of note, tunicamycin did not sensitize the differentiated thyroid epithelial cells to TRAIL-induced apoptosis. Thus, combined treatment with tunicamycin and TRAIL may offer an attractive strategy for safely treating resistant thyroid cancers.     

Triptolide sensitizes lung cancer cells to TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis by inhibition of NF-kappaB activation

TNF-related apoptosis-inducing ligand (TRAIL/Apo- 2L), a newly identified member of the TNF family promotes apoptosis by binding to the transmembrane receptors (TRAIL-R1/DR4 and TRAIL-R2/DR5). TRAIL known to activate NF-kappaB in number of tumor cells including A549 (wt p53) and NCI-H1299 (null p53) lung cancer cells exerts relatively selective cytotoxic affects to the human tumor cell lines without much effect on the normal cells. We set out to identify an agent that would sensitize lung cancer cells to TRAIL-induced apoptosis through inhibition of NF-kappaB activation. We found that triptolide, an oxygenated diterpene extracted and purified from the Chinese herb Tripterygium wilfordii sensitized A549 and NCI-H1299 cells to TRAIL-induced apoptosis through inhibition of NF-kappaB activation. Pretreatment with MG132 which is a well-known NF-kappaB inhibitor by blocking degradation of IkappaBalpha also greatly sensitized lung cancer cells to TRAIL-induced apoptosis. Triptolide did not block DNA binding of NF-kappaB activated by TRAIL as in the case of TNF-alpha. It has been already proven that triptolide blocks transactivation of p65 which plays a key role in NF-kappaB activation. These observations suggest that triptolide may be a potentially useful drug to enhance TRAIL-induced tumor killing in lung cancer.     

Activated protein C differentially regulates both viability and differentiation of osteoblasts mediated by bisphosphonates

Activated protein C (APC) is a cytoprotective anticoagulant that can promote cutaneous healing. We examined the effect of APC on viability and differentiation of the osteoblastic line, MG63, in the presence and absence of bisphosphonates (BPs). Osteoblasts were cultured and treated for 24 or 48 h with Alendronate (Aln), Zoledronate (Zol) or Pamidronate (Pam) at concentrations ranging from 10⁻⁴ to 10⁻⁶ ℳ. Cell differentiation was measured using type 1 collagen production, Alizarin red staining and alkaline phosphatase activity, whereas cell viability was assessed using MTT and crystal violet assays. All three BPs induced MG63 cell death in a dose- and time-dependent manner. Pam- and Zol-related cell death was prevented by APC treatment; however, cell death induced by Aln was accelerated by APC. APC induced MG63 cell differentiation that was enhanced by Aln, but inhibited by Pam or Zol. Endothelial protein C receptor (EPCR) was expressed by MG63 cells and mediated the protective effect of APC on Zol-induced viability. In summary, we have demonstrated that (1) APC favorably regulates MG63 viability and differentiation toward bone growth, (2) APC differentially regulates the effects of specific BPs and (3) at least part of the effects of APC is mediated through EPCR. These findings highlight the potential importance of the PC pathway in bone physiology and provide strong evidence that APC may influence bone cells and has potential to be a therapeutic drug for bone regeneration, depending on concurrent BP treatment.     

Micelle-in-Liposomes for Sustained Delivery of Anticancer Agents That Promote Potent TRAIL-Induced Cancer Cell Apoptosis

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) induces cancer cell-specific apoptosis and has garnered intense interest as a promising agent for cancer treatment. However, the development of TRAIL has been hampered in part because most human cancer cells are resistant to TRAIL. A few small molecules including natural compounds such as piperlongumine (PL) have been reported to sensitize cancer cells to TRAIL. We prepared a novel type of nanomaterial, micelle-in-liposomes (MILs) for solubilization and delivery of PL. PL-loaded MILs were used to sensitize cancer cells to TRAIL. As visualized by cryo-TEM, micelles were successfully loaded inside the aqueous core of liposomes. The MILs increased the water solubility of PL by ~20 fold. A sustained PL release from MILs in physiologically relevant buffer over 7 days was achieved, indicating that the liposomes prevented premature drug release from the micelles in the MILs. Also demonstrated is a potent synergistic apoptotic effect in cancer cells by PL MILs in conjunction with liposomal TRAIL. MILs provide a new formulation and delivery vehicle for hydrophobic anticancer agents, which can be used alone or in combination with TRAIL to promote cancer cell death.     

Preclinical studies for pharmacokinetics and biodistribution of Ad-stTRAIL, an adenovirus delivering secretable trimeric TRAIL for gene therapy

Malignant glioma is the most frequent type in brain tumors. The prognosis of this tumor has not been significantly improved for the past decades and the average survival of patients is less than one year. Thus, an effective novel therapy is urgently needed. TNF-related apoptosis inducing ligand (TRAIL), known to have tumor cell-specific killing activity, has been investigated as a novel therapeutic for cancers. We have developed Ad-stTRAIL, an adenovirus delivering secretable trimeric TRAIL for gene therapy and demonstrated the potential to treat malignant gliomas. Currently, this Ad-stTRAIL gene therapy is under phase I clinical trial for malignant gliomas. Here, we report preclinical studies for Ad-stTRAIL carried out using rats. We delivered Ad-stTRAIL intracranially and determined its pharmacokinetics and biodistribution. Most Ad-stTRAIL remained in the delivered site and the relatively low number of viral genomes was detected in the opposite site of brain and cerebrospinal fluid. Similarly, only small portion of the viral particles injected was found in the blood plasma and major organs and tissues, probably due to the brain-blood barrier. Multiple administrations did not lead to accumulation of Ad-stTRAIL at the injection site and organs. Repeated delivery of Ad-stTRAIL did not show any serious side effects. Our data indicate that intracranially delivered Ad-stTRAIL is a safe approach, demonstrating the potential as a novel therapy for treating gliomas.     

Berberine and Cisplatin Exhibit Synergistic Anticancer Effects on Osteosarcoma MG-63 Cells by Inhibiting the MAPK Pathway

Berberine (BBR) has been reported to have potent anticancer activity and can increase the anticancer effects of chemotherapy drugs. The present study aims to investigate whether BBR and cisplatin (DDP) exert synergistic effects on the osteosarcoma (OS) MG-63 cell line. In the present study, MG-63 cells were treated with BBR and DDP alone or in combination. The effects of these therapeutics on cell viability, colony formation, migration, invasion, nuclear morphology, apoptosis, and the cell cycle, as well as their role in regulating the expression of proteins related to apoptosis, the cell cycle, and the mitogen-activated protein kinase (MAPK) pathway, were determined. The results demonstrated that BBR or DDP significantly inhibited the proliferation of MG-63 cells in a dose- and time-dependent manner. The combination treatment of BBR and DDP exerted a prominent inhibitory effect on proliferation and colony formation. Furthermore, the results showed that the combination treatment of BBR and DDP enhanced the inhibition of cell migration and invasion and reversed the changes in nuclear morphology. The results showed that the combination treatment of BBR and DDP induced apoptosis and cell cycle arrest in the G0/G1 phase. Mechanistically, the combination treatment of BBR and DDP inhibited the expression of MMP-2/9, Bcl-2, CyclinD1, and CDK4, enhanced the expression of Bax and regulated the activity of the MAPK pathway. Collectively, our data suggest that the combination therapy of BBR and DDP markedly enhanced OS cell death.     

Pre-apoptotic sub-population cell sorting from diosgenin apoptosis induced 1547 cells by Sedimentation Field-Flow Fractionation. The effect of channel thickness on sorting performance

Apoptosis is one of the most important phenomena in cell biology. Pre-apoptotic cells, defined as cells engaged in early stages of apoptosis, could be used as a cellular tool to study apoptosis pathways. The human 1547 osteosarcoma cell line and diosgenin (a plant steroid) association was selected as an in vitro cellular apoptosis model. In a previous study, using this model, we demonstrated that SdFFF monitored apoptosis induction as early as 6h after incubation. In this study, we investigated the capacity of Sedimentation Field-Flow Fractionation (SdFFF) to sort an enriched population of pre-apoptotic cells from 1547 cells incubated for 6 h with 40 microM diosgenin. In that way, two different separation devices which differed especially in channel thickness, 125 and 175 microm, were used and compared. Results showed, for the first time, that SdFFF is an effective method to obtain an enriched pre-apoptotic sub-population. These results suggest, as a new application, that SdFFF could be an included tool in the study of apoptotic mechanisms or the kinetic action of apoptotic drugs.     

Pharmacophore Reassignment for Induction of the Immunosurveillance Cytokine TRAIL

Tumor necrosis factor (TNF)‐related apoptosis‐inducing ligand (TRAIL) is an immunosurveillance cytokine that kills cancer cells but demonstrates little toxicity against normal cells. While investigating the TRAIL‐inducing imidazolinopyrimidinone TIC10, a misassignment of its active structure was uncovered. Syntheses of the two isomers, corresponding to the published and reassigned structures, are reported. The ability of each to induce TRAIL expression in macrophages was investigated and it was found that only the compound corresponding to the reassigned structure shows the originally reported activity; the compound corresponding to the published structure is inactive. Importantly, this structural reassignment has furnished a previously unknown antitumor pharmacophore.     

Effects of <Emphasis Type="Italic">A.marina</Emphasis>-Derived Isoquercitrin on TNF-Related Apoptosis-Inducing Ligand Receptor (TRAIL-R) Expression and Apoptosis Induction in Cervical Cancer Cells

TNF-related apoptosis-inducing ligand (TRAIL) is an anticancer agent, which has greater apoptosis inducing capacity, but most of the cancer cells become resistant to TRAIL-induced apoptosis. The combined treatment of TRAIL with natural products could restore the cancer cell sensitivity to recombinant human TRAIL (rhTRAIL) protein and might enhance the TNF-related apoptosis-inducing ligand receptor (TRAIL-R) expression. This investigation was aimed to isolate flavonoids from leaves of Avicennia marina and evaluate their potential for sensitization of rhTRAIL in human cervical cancer cells (SiHa). The methanolic extract of A.marina leaves were purified and structure was elucidated as isoquercitrin by NMR and LC-MS analysis. Isolated isoquercitrin showed cytotoxicity against SiHa cell line at IC₅₀ of 980 μM. Messenger RNA (mRNA) expression of TRAIL-Rs was quantified by qRT-PCR, combination of isoquercitrin, and/or rhTRAIL increased TRAIL-R1 and TRAIL-R2 gene expression by 7 folds and 4 folds, respectively. Also, FACS assay revealed that combined treatment has increased the early apoptosis up to 7.24%. In the present study, we found that isoquercitrin enhances the mRNA expression of TRAIL-Rs, but the percentage of apoptosis was meager, possibly due to the influence of other anti-apoptotic proteins.     

硅烷偶联剂制备及对磷灰石-硅灰石生物玻璃陶瓷的表面改性

采用谷氨酸与硅烷偶联剂(KH-792)缩合反应,制备出一种含酰胺基的硅烷偶联剂,利用其与材料之间的化学结合,将谷氨酸共价固定至磷灰石-硅灰石生物玻璃陶瓷表面,实现表面改性。将改性后的磷灰石-硅灰石生物玻璃陶瓷与人骨肉瘤细胞MG63共培养,评价其体外细胞生物相容性。应用FTIR、SEM、XPS等测试技术分别对合成的偶联剂、改性后的陶瓷材料进行结构、表面形貌及细胞生长情况的表征,结果表明:谷氨酸与KH-792的反应产物有酰胺基生成;含酰胺基的硅烷偶联剂能对磷灰石-硅灰石生物玻璃陶瓷表面进行有效改性;共培养3 d后细胞在材料材料表面大量贴附,MTT实验也证明增殖良好,即含酰胺基的硅烷偶联剂能改善磷灰石-硅灰石生物玻璃陶瓷的体外细胞生物相容性。     

Zoledronic acid: pharmacologic profile of a potent bisphosphonate

Bisphosphonates are an important class of osteotropic compounds that are effective in treating benign and malignant skeletal diseases characterized by enhanced osteoclast-mediated bone resorption (i.e., osteoporosis, Paget’s disease, and tumor-induced osteolysis). The evolution of bisphosphonates has led to compounds with ever-increasing potency. First-generation bisphosphonates, including etidronate and clodronate, contained simple side chains and were relatively weak inhibitors of bone resorption. Second-generation compounds, including pamidronate, alendronate, and ibandronate, have an aliphatic R² side chain containing a single nitrogen atom. These nitrogen-containing bisphosphonates (N-BPs) are up to 100-fold more potent than the first-generation compounds. Zoledronic acid, a novel N-BP with an imidazole substituent, has demonstrated more potent inhibition of osteoclast-mediated bone resorption than all other bisphosphonates in both in vitro and in vivo preclinical models. Recent data suggest that N-BPs inhibit farnesyl diphosphate (FPP) synthase, an enzyme in the mevalonate biosynthetic pathway that is critical for protein prenylation and activation of important signaling molecules. Inhibition of FPP synthase also leads to production of triphosphoric acid 1-adenosin-5′yl ester 3-[3-methylbut-3-enyl] ester (ApppI), which induces apoptosis of osteoclasts and tumor cells. Our current knowledge of the pharmacology of N-BPs at the molecular level largely explains their observed effects on bone metabolism and tumor growth in animal models and their clinical activity in the treatment of benign and malignant bone diseases.     

Quinacrine Mediated Sensitization of Glioblastoma (GBM) Cells to TRAIL through MMP‐Sensitive PEG Hydrogel Carriers

Overcoming drug resistance is a major challenge for cancer therapy. Tumor necrosis factor α‐related apoptosis‐inducing ligand (TRAIL) is a potent therapeutic as an activator of apoptosis, particularly in tumor but not in healthy cells. However, its efficacy is limited by the resistance of tumor cell populations to the therapeutic substance. Here, we have addressed this limitation through the development of a controlled release system, matrix‐metalloproteinase (MMP)‐sensitive and arg‐gly‐asp‐ser (RGDS) peptide functionalized poly (ethylene‐glycol) (PEG) particles which are synthesized via visible‐light‐induced water‐in‐water emulsion polymerization. Quinacrine (QC), a recently discovered TRAIL sensitizer drug, is loaded into the hydrogel carriers and the influence of this system on the apoptosis of a malignant type of brain cancer, glioblastoma multiforme (GBM), has been investigated in detail. The results suggest that MMP‐sensitive particles are cytocompatible and superior to promote TRAIL‐induced apoptosis in GBM cells when loaded with QC. Compared to QC and TRAIL alone, combination of QC‐loaded PEG hydrogel and TRAIL demonstrates synergistic apoptotic inducing behavior. Furthermore, QC‐loaded particles, but not QC or PEG‐hydrogels alone, enhance apoptosis as is measured through expression of apoptosis‐related genes. This system is promising to significantly improve the efficacy of chemotherapeutic drugs and suggests a combination treatment for GBM therapy.

     

The coumarin psoralidin enhances anticancer effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)

Coumarins are a very common type of secondary plant metabolites with a broad spectrum of biological activities. Psoralidin is a naturally occurring furanocoumarin isolated from Psoralea corylifolia possessing anticancer and chemopreventive properties. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) triggers apoptosis in cancer cells with no toxicity toward normal tissues. Endogenous TRAIL plays an important role in immune surveillance and defence against cancer cells. Coumarins can modulate TRAIL-mediated apoptosis in cancer cells. We examined the cytotoxic and apoptotic activities of psoralidin in combination with TRAIL on HeLa cancer cells. The cytotoxicity was measured by MTT and LDH assays. The apoptosis was detected using annexin V-FITC staining and mitochondrial membrane potential was evaluated using DePsipher staining by fluorescence microscopy. Death receptor (TRAIL-R1/DR4 and TRAIL-R2/DR5) expression was analyzed using flow cytometry. Psoralidin enhanced TRAIL-induced apoptosis in HeLa cells through increased expression of TRAIL-R2 death receptor and depolarization of mitochondrial membrane potential. Our study indicated that psoralidin augmented the anticancer effects of TRAIL and confirmed a potential use of coumarins in cancer chemoprevention.     

An Unexpected Role of Hyaluronic Acid in Trafficking siRNA Across the Cellular Barrier: The First Biomimetic,Anionic, Non‐Viral Transfection Method

Circulating nucleic acids, such as short interfering RNA (siRNA), regulate many biological processes; however, the mechanism by which these molecules enter the cell is poorly understood. The role of extracellular‐matrix‐derived polymers in binding siRNAs and trafficking them across the plasma membrane is reported. Thermal melting, dynamic light scattering, scanning electron microscopy, and computational analysis indicate that hyaluronic acid can stabilize siRNA via hydrogen bonding and Van der Waals interactions. This stabilization facilitated HA size‐ and concentration‐dependent gene silencing in a CD44‐positive human osteosarcoma cell line (MG‐63) and in human mesenchymal stromal cells (hMSCs). This native HA‐based siRNA transfection represents the first report on an anionic, non‐viral delivery method that resulted in approximately 60 % gene knockdown in both cell types tested, which correlated with a reduction in translation levels.     

Sialic acid surface decoration enhances cellular uptake and apoptosis-inducing activity of selenium nanoparticles

A simple method for fabrication of sialic acid surface-decorated selenium nanoparticles (SA-Se-NPs) with enhanced cancer-targeting and cell-penetrating abilities has been demonstrated in the present study. Monodisperse and homogeneous spherical SA-Se-NPs with striking stability were prepared under the optimized conditions. SA surface decoration significantly increased the cellular uptake and cytotoxicity of Se-NPs in HeLa human cervical carcinoma cells. Treatments of SA-Se-NPs induced dose-dependent apoptosis in HeLa cells, as evidenced by increase in sub-G1 cell populations, nuclear condensation and formation of apoptotic bodies. Further investigation on molecular mechanisms reveals that SA-Se-NPs triggered cancer cell apoptosis through activation of caspase-3 and subsequent cleavage of PARP.     

糖原合成酶激酶-3和细胞周期蛋白依赖性激酶抑制剂paullones的研究进展

对抑制剂paullones的来源、合成,以及与激酶相互作用的分子机理、选择性、细胞效应进行了综述.指出糖原合成酶激酶-3(GSK-3)是参与糖代谢的主要限速酶之一,人类多种疾病均与其活性调节异常有关;细胞周期蛋白依赖性激酶(CDKs)是一类丝氨酸/苏氨酸蛋白激酶,能够促使细胞进行有序的生长、增殖、休眠或进入凋亡.以CDKs为靶点的药物可以阻断细胞周期,控制癌细胞增殖,从而达到抗肿瘤的目的.Paullones对CDKs和GSK-3均具有良好的选择性,是CDKs和GSK-3的有效抑制剂;迄今为止,文献报道的paullones化合物接近120个.