Inhibitory effects of Lentinus edodes mycelia polysaccharide on α-glucosidase, glycation activity and high glucose-induced cell damage.

At present, diabetes and diabetic complications have become one of the serious diseases affecting human health. In this study, the inhibitory effects of Lentinus edodes mycelia polysaccharide (LMP) on α-glucosidase activity, the formation of advanced glycation end products (AGEs) and high glucose-induced human umbilical vein endothelial cells (HUVECs) damage were explored. The interaction between LMP and α-glucosidase and the inhibition against AGEs formation were investigated with spectroscopic techniques. The results revealed that LMP had a reversible inhibition on α-glucosidase activity in a mixed-type manner. When the concentration of LMP was 2.7 mM, the inhibition rate was 34.38 %. LMP quenched the fluorescence of α-glucosidase through the static quenching and formed the LMP-α-glucosidase complex. At 310 K, the number of binding sites (n) and binding constant (Kb) were 1.01 and 3.71 × 104 L mol-1, respectively. In addition, LMP could inhibit the formation of AGEs. Compared with 40 mM glucose treatment group, treatment with 0.05 mM LMP for 48 h increased the cell viability from 70.17% to 91.14% and decreased ROS production from 3.33-fold to 1.21-fold. LMP inhibited high glucose-induced activation of MAPK signaling pathways. These findings may promote the application of LMP in the functional food industry.

Retinoic acid receptor gamma is targeted by microRNA-124 and inhibits neurite outgrowth.

During brain development, neurite outgrowth is required for brain development and is regulated by many factors. All-trans retinoic acid (RA) is an important regulator of cell growth and differentiation. MicroRNA-124 (miR-124), a brain-specific microRNA, has been implicated in stimulating neurite growth. In this study, we found that retinoic acid receptor gamma (RARG) expression was decreased, whereas miR-124 expression was increased during neural differentiation in mouse Neuroblastoma (N2a) Cells, P19 embryonal carcinoma (P19) cells, and mouse brain, as detected by immunoblotting or RT-qPCR. And we proved that miR-124 inhibited RARG expression by binding to the 3' UTR of RARG with a luciferase reporter assay. Upregulation of miR-124 (using miR-124 overexpressing plasmid and miR-124 mimic) led to a significant decrease in RARG protein in N2a cells and primary neurons. Therefore, we asked whether and how the miR-124/RARG axis regulates neuronal outgrowth, which is poorly understood. Strikingly, RARG knockdown by shRNA stimulated neurite growth in N2a cells and primary neurons, whereas RARG overexpression (without 3' UTR) inhibited neurite growth in N2a cells, P19 cells, and primary neurons. Furthermore, RARG knockdown could partially eliminate neurite outgrowth defects caused by the inhibitor of miR-124, while RARG overexpression could reverse the neurite outgrowth enhancing effect of the upregulation of miR-124. Collectively, the data reveal that miR-124/RARG axis is critical for neurite outgrowth. RARG emerges as a new target regulated by miR-124 that modulates neurite outgrowth, providing a novel context in which these two molecules function.

Xinjiang herbal tea exerts immunomodulatory activity via TLR2/4-mediated MAPK signaling pathways in RAW264.7 cells and prevents cyclophosphamide-induced immunosuppression in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: A multi-herb Chinese medicinal formula consisting of a variety of medicinal and edible materials has long been consumed as a hot drink and immune enhancer for its efficiency to increase disease resistance in Xinjiang, China. However, no fundamental data has been collected associated with traditional consumption. The present work was designed to evaluate the immunostimulatory role of Xinjiang herbal tea (XMT-WE) in RAW 264.7 macrophages and cyclophosphamide (CTX)-induced immunosuppression mice model. MATERIALS AND METHODS: RAW 264.7 cells were treated with various concentrations of XMT-WE. Nitric oxide (NO) levels were determined using Griess reagents, and pro-inflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor (TNF)-α were investigated with a cytometric bead array kit. The effects on mRNA expression of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, and TNF-α were investigated. Furthermore, activation of nuclear factor (NF)-κB and AP-1 mitogen-activated protein kinase (MAPK) signaling pathways was investigated. RESULTS: Pre-treatment with XMT-WE significantly increased secretion of NO, IL-6, and TNF-α. In addition, XMT-WE markedly increased expression of iNOS, COX-2, and TNF-α as well as AP-1 and NF-κB translocation from the cytoplasm into the nucleus, which was associated with an increase of phosphorylated ERK, JNK, and p38 as well as membrane receptors such as toll-like receptor (TLR) 2 and TLR4. Moreover, XMT-WE promoted the secretion of interleukin-2 (IL-2) and interferon-γ (IFN-γ) in cyclophosphamide (CTX)-induced immunosuppressive mice. CONCLUSION: These results indicated that XMT-WE at 50 µg/ml exerts immunomodulatory activity via TLR2/4-mediated MAPK signaling pathways in RAW 264.7 cells. Furthermore, in vivo experiments revealed that XMT-WE at the dose of 50 and 100 mg/kg strongly stimulated inflammatory cytokines.

Pharmacological effect of prohibited combination pair Panax ginseng and Veratrum nigrum on colorectal metastasis in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: The pharmacological effect derived from herb-herb interaction is important to constitute the prescription especially in traditional oriental medicine. The relationship of two medicinal herbs is called "couplet medicinals" which is used in pair for the purpose of enhancing the therapeutic effect, reducing the toxic effect or the adverse effect. The "Eighteen Incompatible Medicaments" constitute one of the contents in the incompatibility of traditional oriental drugs in a prescription. Among the "Eighteen Incompatible Medicaments", the roots and rhizomes of Veratrum nigrum (VN), is incompatible with the roots and rhizomes of Panax ginseng (PG). However, definite evidences of adverse effect by these combinations has yet to be reported. MATERIALS AND METHODS: The aim of the present study was to investigate the effects of ethanol extracts of PG, VN, and their combination (P + V) on the metastatic ability of colorectal cancer (CRC) cells using WST assay, flow cytometry, western blot analysis, real-time RT-PCR, immunofluorescence, migration assay, invasion assay, zymography, and an in vivo experiment with a lung-metastasis mouse model. RESULTS: The PG extract decreased cell proliferation by inducing cell cycle arrest and apoptosis of CRC cells. In addition, PG inhibited metastatic abilities of CRC cells including Epithelial-Mesenchymal Transition, migration, and invasion. Additionally, the PG extract suppressed lung metastasis of the CRC cells in the mouse model. However, the P + V extract exhibited weaker anti-proliferative and anti-metastatic effects than PG alone. CONCLUSION: Based on these results, the P + V couplet medicinal attenuates the anti-metastatic effects of PG, both in vitro and in vivo.

The inhibitory effect of Aconiti Sinomontani Radix extracts on the proliferation and migration of human synovial fibroblast cell line SW982.

ETHNOPHARMACOLOGICAL RELEVANCE: Aconiti Sinomontani Radix is frequently used in the treatment of Bi syndrome in traditional Chinese medicine. Several reports indicate that Aconiti Sinomontani Radix has therapeutic effects for rheumatoid arthritis (RA). However, the cellular mode of action is still unclear. To investigate the effect of alkaloid extracts of Aconiti Sinomontani Radix on proliferation and migration of human synovial sarcoma SW982 cells as well as the molecular mechanism underlying. MATERIALS AND METHODS: SW982 cells were examined for proliferation by a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) method. Wound scratch assays were performed to assess the migrated rate of SW982 cells. Quantitative real-time PCR was used to measure the mRNA expression levels of Wnt5a, Runx2, MMP3, and Bmp2. Western blotting was used to measure the phosphorylated levels of JNK and NF-κB as well as the expression of MMP3. RESULTS: The alkaloid extract from Aconiti Sinomontani Radix (MQA) and MQB, which removed lappaconitine from MQA significantly inhibited the proliferation of SW982 in a dose-dependent manner. The proliferation inhibitory effect of MQB was more potent. Incubation with 10µg/ml MQB for 12, 24, and 36h inhibited the migration of SW982 cells by 83%, 58%, and 42%, respectively. Treatment with different concentrations of MQB for 24h inhibited mRNA expression of Wnt5a, Runx2, and MMP3, but Bmp2 mRNA expression was elevated by MQB. Further, MQB inhibited phosphorylation of JNK and NF-κB p65 as well as MMP3 expression by Western blotting analysis. CONCLUSION: The results showed that MQB inhibited proliferation and migration of SW982 cells possibly through suppressing Wnt5a-mediated JNK and NF-κB pathways. These results indicated that MQB might be an active extract of Aconiti Sinomontani Radix for targeting fibroblast-like synoviocytes (FLS) and be potential for RA therapy.

Reversal of cisplatin resistance in human gastric cancer cells by a wogonin-conjugated Pt(IV) prodrug via attenuating Casein Kinase 2-mediated Nuclear Factor-κB pathways.

Pt(IV) prodrugs, with two additional coordination sites in contrast to Pt(II) drugs, have been actively studied nowadays, for they can perform well in enhancing the accumulation and retention of the corresponding Pt(II) drugs in cancer cells. Our designed Pt(II) drug, DN604, was recently found to exhibit significant anticancer activity and low toxicity, while, wogonin, a naturally O-methylated flavones, has been widely investigated for its tumor therapeutic potential. Thus, two Pt(IV)-based prodrugs were derived by addition of a wogonin unit to the axial position of DN604 and its analogue DN603 via a linker group. In vitro cytotoxicity assay indicated that the resulting compound 8 not only inherited the genotoxicity of DN604 on gastric cancer cells, but also obtained the COX inhibitory property arising from wogonin. Further studies revealed that compound 8 caused the accumulation of ROS production and decreased the mitochondrial membrane potential (ΔΨm). The CK2α kinase activity assay, ChIP and luciferase assays showed that CK2 plays an important role in the blockade of compound 8 on activated NF-κB survival pathways, which were established for sensitivity of cancer cells to platinum drugs. Similarly in vivo, in nude mice with SGC-7901/cDDP xenografts, compound 8 improved the effectiveness of DN604 via reversing tumor resistance and maintaining low toxicity. Overall, compound 8 is a promising Pt(IV) prodrug, which could be used to promote the anticancer activity of its counterpart Pt(II) species and reverse drug resistance via attenuating CK2-mediated NF-κB pathways during platinum-based chemotherapies.

Gigantol from Dendrobium chrysotoxum Lindl. binds and inhibits aldose reductase gene to exert its anti-cataract activity: An in vitro mechanistic study.

ETHNOPHARMACOLOGICAL RELEVANCE: Dendrobium. chrysotoxum Lindl is a commonly used species of medicinal Dendrobium which belongs to the family of Orchidaceae, locally known as "Shihu" or "Huangcao". D. chrysotoxum Lindl is widely known for medicinal values in traditional Chinese medicine as it possesses anti-inflammatory, anti-hyperglycemic induction, antitumor and antioxidant properties. STUDY AIM: To characterize the interaction between gigantol extracted from D. chrysotoxum Lindl and the AR gene, and determine gigantol's efficacy against cataractogenesis. MATERIALS AND METHODS: Human lens epithelial cells (HLECs) were induced by glucose as the model group. Reverse transcription polymerase chain reaction (RT-PCR) was used to assess AR gene expression. Then, the mode of interaction of gigantol with the AR gene was evaluated by UV-visible spectroscopy, atomic force microscope (AFM) and surface-enhanced Raman spectroscopy (SERS). The binding constant was determined by UV-visible. RESULTS: Gigantol depressed AR gene expression in HLECs. UV-visible spectra preliminarily indicated that interaction between the AR gene and gigantol may follow the groove mode, with a binding constant of 1.85×103L/mol. Atomic force microscope (AFM) data indicated that gigantol possibly bound to insert AR gene base pairs of the double helix. Surface-enhanced Raman spectroscopy (SERS) studies further supported these observations. CONCLUSION: Gigantol extracted from D. chrysotoxum Lindl not only has inhibitory effects on aldose reductase, but also inhibits AR gene expression. These findings provide a more comprehensive theoretical basis for the use of Dendrobium for the treatment of diabetic cataract.

The antihypercholesterolemic effect of columbamine from Rhizoma Coptidis in HFHC-diet induced hamsters through HNF-4α/FTF-mediated CYP7A1 activation.

The aim of this study was to investigate the antihypercholesterolemic activity and potential molecular mechanism of columbamine (COL) that was prepared by extraction from Rhizoma Coptidis in hamsters and HepG2 cells. The results displayed that the COL from Rhizoma Coptidis was a safe natural compound with a LD50 0f 1524.6mg/kg and no detectable toxic symptoms during the observation of chronic toxicity. COL dose-dependently reversed the abnormal lipid levels induced by HFHC diet. Specifically, COL(M) and COL(H) significantly reduced the blood lipid levels(TC, TG and LDL-c) and enhanced the fecal contents of TBA by 21.8% and 25.1% respectively in hamsters. COL up-regulated the genes of CYP8B1, CYP7A1 and LDLR in mRNA and protein level, and down-regulated those of HMGCR to a different degree. Especially, CYP7A1 were significantly up-regulated by COL in hamsters (p<0.01). Further analysis indicated that COL obviously activated the mRNA and protein expression of the transcription factors FTF, HNF-4α, and inhibited those of SHP. Promoter luciferase assay showed that COL induced the expression of FTF and HNF-4α, further transactivating CYP7A1, which accelerated the conversion of liver cholesterol to bile acids. It concluded that the COL showed high lipid-lowering activities through indirectly transactivating CYP7A1 by upregulating FTF and HNF-4α, and directly activating CYP7A1 catalytic activity by strongly interacting with receptor and ligand, therefore promoting cholesterol catabolism and accelerating the excretion of bile acids.

Salinomycin enhances cisplatin-induced cytotoxicity in human lung cancer cells via down-regulation of AKT-dependent thymidylate synthase expression.

Salinomycin, a polyether antibiotic, acts as a highly selective potassium ionophore and has anticancer activity on various cancer cell lines. Cisplatin has been proved as chemotherapy drug for advanced human non-small cell lung cancer (NSCLC). Thymidylate synthase (TS) is a key enzyme in the pyrimidine salvage pathway, and increased expression of TS is thought to be associated with resistance to cisplatin. In this study, we showed that salinomycin (0.5-2µg/mL) treatment down-regulating of TS expression in an AKT inactivation manner in two NSCLC cell lines, human lung adenocarcinoma A549 and squamous cell carcinoma H1703 cells. Knockdown of TS using small interfering RNA (siRNA) or inhibiting AKT activity with PI3K inhibitor LY294002 enhanced the cytotoxicity and cell growth inhibition of salinomycin. A combination of cisplatin and salinomycin resulted in synergistic enhancement of cytotoxicity and cell growth inhibition in NSCLC cells, accompanied with reduced activation of phospho-AKT, and TS expression. Overexpression of a constitutive active AKT (AKT-CA) expression vector reversed the salinomycin and cisplatin-induced synergistic cytotoxicity. In contrast, pretreatment with LY294002 further decreased the cell viability in salinomycin and cisplatin cotreated cells. Our findings suggested that the down-regulation of AKT-mediated TS expression by salinomycin enhanced the cisplatin-induced cytotoxicity in NSCLC cells. These results may provide a rationale to combine salinomycin with cisplatin for lung cancer treatment.

Propofol inhibits hERG K+ channels and enhances the inhibition effects on its mutations in HEK293 cells.

QT interval prolongation, a potential risk for arrhythmias, may result from gene polymorphisms relevant to cardiomyocyte repolarization. Another noted cause of QT interval prolongation is the administration of chemical compounds such as anesthetics, which may affect a specific type of cardiac K+ channel encoded by the human ether-a-go-go-related gene (hERG). hERG K+ current was recorded using whole-cell patch clamp in human embryonic kidney (HEK293) cells expressing wild type (WT) or mutated hERG channels. Expression of hERG K+ channel proteins was evaluated using western blot and confirmed by fluorescent staining and imaging. Computational modeling was adopted to identify the possible binding site(s) of propofol with hERG K+ channels. Propofol had a significant inhibitory effect on WT hERG K+ currents in a concentration-dependent manner, with a half-maximal inhibitory concentration (IC50) of 60.9±6.4µM. Mutations in drug-binding sites (Y652A or F656C) of the hERG channel were found to attenuate hERG current blockage by propofol. However, propofol did not inhibit the trafficking of hERG protein to the cell membrane. Meanwhile, for the three selective hERG K+ channel mutant heterozygotes WT/Q738X-hERG, WT/A422T-hERG, and WT/H562P-hERG, the IC50 of propofol was calculated as 14.2±2.8µM, 3.3±1.2µM, and 5.9±1.9µM, respectively, which were much lower than that for the wild type. These findings indicate that propofol may potentially increase QT interval prolongation risk in patients via direct inhibition of the hERG K+ channel, especially in those with other concurrent triggering factors such as hERG gene mutations.

Paeoniflorin inhibits high glucose-induced macrophage activation through TLR2-dependent signal pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: Paeoniflorin(PF), extracted from the root peeled of Paeonia lactiflora Pall(Family: Ranunculaceae), has therapeutic potential in many animal models of inflammatory diseases. AIM OF THE STUDY: Although the anti-inflammatory efficacy of PF has been well illustrated in several animal models, whether it could attenuate diabetic nephropathy and detailed mechanisms are still obscure. Till now, accumulating evidence has proposed the pivotal role of toll-like receptors (TLRs) in renal inflammation in diabetic patients. In this setting, the current study aimed to investigate the effects and underlying mechanism of PF on high glucose-induced activation of toll like-receptor 2 (TLR2) signaling in macrophages. MATERIALS AND METHODS: Bone marrow-derived macrophages (BMDM) were isolated from male Tlr2tm1kir (TLR2-/-) mice and wild-type littermates (C57BL/6JWT). The level of TLR2 and activation of downstream signaling were evaluated in response to 30mmol/L high glucose (HG)-containing medium. Macrophages behaviors, which include cell viability, migration and inflammatory cytokines production, were also determined. RESULTS: PF suppressed HG-induced production of TLR2, activation of downstream signaling and synthesis of inducible nitric oxide synthase (iNOS). PF could further inhibit MyD88-dependent pathway in HG-induced models in which TLR2 was knocked out. Moreover, deletion of TLR2 inhibited the HG-induced activation of MyD88-dependent pathway, but not TIR domain containing adapter inducing interferon-ß (Trif) signal pathway in BMDMs. As HG stimulation polarizes macrophages into M1 phenotype, treatment of PF or knockout of TLR2 significantly reduces M1 markers on the membrane of macrophages. Additionally, levels of inflammatory cytokines and iNOS were remarkably reduced in response to PF or TLR2 deficiency. CONCLUSION: Collectively, these data demonstrated that HG activated macrophages primarily through TLR2-dependent mechanisms which aggravated the severity of renal inflammation and eventually contributed to DN. Additionally, PF might be applied as a potential therapeutic agent in the battle against progressive DN.

The antioxidant protein PARK7 plays an important role in cell resistance to Cisplatin-induced apoptosis in case of clear cell renal cell carcinoma.

Clear cell renal cell carcinoma (ccRCC) is the most malignant tumor in the adult kidney. Many factors are responsible for the development and progression of this tumor. Increased reactive oxygen species accumulation and altered redox status have been observed in cancer cells and this biochemical property of cancer cells can be exploited for therapeutic benefits. In earlier work we identified and characterize Protein DJ-1 (PARK7) as an oxidative stress squevenger in renal cells exposed to oxidative stress. To investigate whether the PARK7 or other oxidative stress proteins play a role in the renal cell carcinoma and its sensitivity or resistance to cytostatic drug treatment, differential proteomics analysis was performed with a cell model for clear cell renal carcinoma (Caki-2 and A498). Caki-2 cells were treated with cisplatin and differentially expressed proteins were investigated. The cisplatin treatment resulted in an increase in reactive oxygen species accumulation and ultimately apoptosis of Caki-2 and A498 cells. In parallel, the apoptotic effect was accompanied by a significant downregulation of antioxidant proteins especially PARK7. Knockdown of PARK7 using siRNA and overexpression using plasmid highlights the role of PARK7 as a key player in renal cell carcinoma response to cisplatin induced apoptosis. Overexpression of PARK7 resulted in significant decrease in apoptosis, whereas knockdown of the protein was accompanied by an increase in apoptosis in Caki-2 and A498 cells treated with cisplatin. These results highlights for the first time the important role of PARK7 in cisplatin induced apoptosis in clear renal cell carcinoma cells.

Astaxanthin down-regulates Rad51 expression via inactivation of AKT kinase to enhance mitomycin C-induced cytotoxicity in human non-small cell lung cancer cells.

Astaxanthin has been demonstrated to exhibit a wide range of beneficial effects, including anti-inflammatory and anti-cancer properties. However, the molecular mechanism of astaxanthin-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells has not been identified. Rad51 plays a central role in homologous recombination, and studies show that chemo-resistant carcinomas exhibit high levels of Rad51 expression. In this study, astaxanthin treatment inhibited cell viability and proliferation of two NSCLC cells, A549 and H1703. Astaxanthin treatment (2.5-20 µM) decreased Rad51 expression and phospho-AKT(Ser473) protein level in a time and dose-dependent manner. Furthermore, expression of constitutively active AKT (AKT-CA) vector rescued the decreased Rad51 mRNA and protein levels in astaxanthin-treated NSCLC cells. Combined treatment with phosphatidylinositol 3-kinase (PI3K) inhibitors (LY294002 or wortmannin) further decreased the Rad51 expression in astaxanthin-exposed A549 and H1703 cells. Knockdown of Rad51 expression by transfection with si-Rad51 RNA or cotreatment with LY294002 further enhanced the cytotoxicity and cell growth inhibition of astaxanthin. Additionally, mitomycin C (MMC) as an anti-tumor antibiotic is widely used in clinical NSCLC chemotherapy. Combination of MMC and astaxanthin synergistically resulted in cytotoxicity and cell growth inhibition in NSCLC cells, accompanied with reduced phospho-AKT(Ser473) level and Rad51 expression. Overexpression of AKT-CA or Flag-tagged Rad51 reversed the astaxanthin and MMC-induced synergistic cytotoxicity. In contrast, pretreatment with LY294002 further decreased the cell viability in astaxanthin and MMC co-treated cells. In conclusion, astaxanthin enhances MMC-induced cytotoxicity by decreasing Rad51 expression and AKT activation. These findings may provide rationale to combine astaxanthin with MMC for the treatment of NSCLC.

Minocycline enhances mitomycin C-induced cytotoxicity through down-regulating ERK1/2-mediated Rad51 expression in human non-small cell lung cancer cells.

Minocycline is a semisynthetic tetracycline derivative; it has anti-inflammatory and anti-cancer effects distinct from its antimicrobial function. However, the molecular mechanism of minocycline-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells has not been identified. Rad51 plays a central role in homologous recombination and high levels of Rad51 expression are observed in chemo- or radioresistant carcinomas. Our previous studies have shown that the MKK1/2-ERK1/2 signal pathway maintains the expression of Rad51 in NSCLC cells. In this study, minocycline treatment inhibited cell viability and proliferation of two NSCLC cells, A549 and H1975. Treatment with minocycline decreased Rad51 mRNA and protein levels through MKK1/2-ERK1/2 inactivation. Furthermore, expression of constitutively active MKK1 (MKK1-CA) vectors significantly rescued the decreased Rad51 protein and mRNA levels in minocycline-treated NSCLC cells. However, combined treatment with MKK1/2 inhibitor U0126 and minocycline further decreased the Rad51 expression and cell viability of NSCLC cells. Knocking down Rad51 expression by transfection with small interfering RNA of Rad51 enhanced the cytotoxicity and cell growth inhibition of minocycline. Mitomycin C (MMC) is typically used as a first or second line regimen to treat NSCLC. Compared to a single agent alone, MMC combined with minocycline resulted in cytotoxicity and cell growth inhibition synergistically in NSCLC cells, accompanied with reduced activation of phospho-ERK1/2, and reduced Rad51 protein levels. Overexpression of MKK1-CA or Flag-tagged Rad51 could reverse the minocycline and MMC-induced synergistic cytotoxicity. These findings may have implications for the rational design of future drug regimens incorporating minocycline and MMC for the treatment of NSCLC.

Gemcitabine-based therapy for pancreatic cancer using the squalenoyl nucleoside monophosphate nanoassemblies.

Gemcitabine is currently the most effective agent against advanced pancreatic cancer. However, the major therapeutic hurdles using gemcitabine include rapid inactivation by blood deaminases and fast development of cell chemoresistance, induced by down-regulation of deoxycytidine kinase or nucleoside transporters. To overcome the above drawbacks we designed recently a novel nanomedicine strategy based on squalenoyl prodrug of 5'-monophosphate gemcitabine (SQdFdC-MP). This amphiphilic conjugate self-organized in water into unilamellar vesicles with a mean diameter of 100 nm. In this study the antitumor efficacy of SQdFdC-MP nanoassemblies (NAs) on chemoresistant and chemosensitive pancreatic adenocarcinoma models have been investigated. Cell viability assays showed that SQdFdC-MP NAs displayed higher antiproliferative and cytotoxic effects, particularly in chemoresistant pancreatic tumor cells. In in vivo studies, SQdFdC-MP NAs decreased significantly the growth (∼70%) of human MiaPaCa2 xenografts, also preventing tumor cell invasion, whereas native dFdC did not display any anticancer activity when tumor growth inhibition was only 35% with SQdFdC NAs. These results correlated with a reduction of Ki-67 antigen and the induction of apoptosis mediated by caspase-3 activation in tumor cells. These findings demonstrated the feasibility of utilizing SQdFdC-MP NAs to make tumor cells more sensitive to gemcitabine and thus providing an efficient new therapeutic alternative for pancreatic adenocarcinoma.

Inhibitory effect of Ecliptae herba extract and its component wedelolactone on pre-osteoclastic proliferation and differentiation.

ETHNOPHARMACOLOGICAL RELEVANCE: Ecliptae herba, also known as "Mo-Han-Lian", has long been used in China to nourish Kidney and thereafter strengthen bones. Accumulating evidence indicates that extracts of Ecliptae herba have antiosteoporotic effect. However, the effective compounds and cellular mode of action are still unclear. To investigate the effect of ethyl acetate extract of Ecliptae herba (EAE) and its component wedelolactone on proliferation and differentiation of preosteoclastic RAW264.7 cells as well as proliferation of bone marrow stromal cells (BMSC). MATERIALS AND METHODS: RAW264.7 and BMSC were examined for proliferation by a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) method. Tartrate-resistant acid phosphatase (TRAP) activity of RAW264.7 was measured by using p-nitrophenyl sodium phosphate (pNPP) assay after the cells were treated with 30ng/ml receptor activator for nuclear factor-κ B ligand (RANKL) plus various concentrations of EAE, wedelolactone or alendronate. The formation of multinucleated TRAP-positive RAW264.7 cells was observed by using a TRAP-staining kit. RESULTS: Treatment of RAW264.7 cells with EAE at high doses (20µg/ml and 40µg/ml) or wedelolactone at 10µg/ml resulted in a decrease in proliferation of RAW264.7 cells. Low doses of EAE (5, 10µg/ml) and wedelolactone (2.5µg/ml) inhibited RANKL-induced TRAP activity by 20.3%, 37.9%, and 48.3%. The inhibitory effect of wedelolactone is more potent than that of alendronate, an anti-resorptive drug. Morphological changes revealed that 5µg/ml EAE and 2.5µg/ml wedelolactone reduced the number of multinucleated osteoclast-like cells. At the high doses, EAE (20µg/ml) and wedelolactone (10µg/ml) inhibited the growth of BMSC. CONCLUSIONS: EAE and its component wedelolactone inhibited osteoclast RAW264.7 proliferation and differentiation at the low doses, but at the high doses, showed cytotoxic effect on BMSC. These results indicated that EAE and wedelolatone might be potential alternative therapy for osteoporosis.

Tamoxifen enhances erlotinib-induced cytotoxicity through down-regulating AKT-mediated thymidine phosphorylase expression in human non-small-cell lung cancer cells.

Tamoxifen is a triphenylethylene nonsteroidal estrogen receptor (ER) antagonist used worldwide as an adjuvant hormone therapeutic agent in the treatment of breast cancer. However, the molecular mechanism of tamoxifen-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells has not been identified. Thymidine phosphorylase (TP) is an enzyme of the pyrimidine salvage pathway which is upregulated in cancers. In this study, tamoxifen treatment inhibited cell survival in two NSCLC cells, H520 and H1975. Treatment with tamoxifen decreased TP mRNA and protein levels through AKT inactivation. Furthermore, expression of constitutively active AKT (AKT-CA) vectors significantly rescued the decreased TP protein and mRNA levels in tamoxifen-treated NSCLC cells. In contrast, combination treatment with PI3K inhibitors (LY294002 or wortmannin) and tamoxifen further decreased the TP expression and cell viability of NSCLC cells. Knocking down TP expression by transfection with small interfering RNA of TP enhanced the cytotoxicity and cell growth inhibition of tamoxifen. Erlotinib (Tarceva, OSI-774), an orally available small molecular inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, is approved for clinical treatment of NSCLC. Compared to a single agent alone, tamoxifen combined with erlotinib resulted in cytotoxicity and cell growth inhibition synergistically in NSCLC cells, accompanied with reduced activation of phospho-AKT and phospho-ERK1/2, and reduced TP protein levels. These findings may have implications for the rational design of future drug regimens incorporating tamoxifen and erlotinib for the treatment of NSCLC.