Fabrication of Ce doped TiO2 for efficient organic pollutants removal from wastewater

Pristine and Ce doped TiO₂ nanoparticles were fabricated for toxic pollutants removal from wastewater. Pristine, 2% Ce and 4% Ce doped TiO₂ photocatalysts were produced via hydrothermal route. 4% Ce doped TiO₂ exhibited 2.41 eV bandgap which is smaller than pure TiO_2. The morphology was also investigated and it was established that doping of Ce ions enhanced the surface roughness and reduced the particle size. The surface area was characterized through BET analysis and 4% Ce-TiO₂ possess higher surface with large pore diameter which helped the photocatalytic activity. The prepared photocatalysts were investigated on reduction of pollutants from wastewater under visible light. Higher efficiency was obtained for 4% Ce-TiO₂ photocatalyst for both model pollutants. The "k" value possessed was also higher for the doped TiO₂ catalyst. These analysis reports the optimum level of ceria doping to enhance morphology, surface area and it increased activity than bare TiO₂. 4% Ce-TiO₂ will be the potential candidate for efficient wastewater management. The 4% Ce doped TiO₂ photocatalyst provided 77% and 88% on reducing MB and RhB dyes. The dopant has developed higher surface area, morphology and good recombination rate which reduced the toxic pollutants and changed the wastewater to reuse.

Investigation of PEG directed Sb2WO6 for dyes removal from wastewater

Pristine and polyethylene glycol assisted antimony tungstate (Sb₂WO₆) was developed via hydrothermal route. The pristine and surfactant assisted Sb₂WO₆ were further exemplified to reveal the properties of the samples. The bandgap calculated for Sb₂WO₆, 5 ml PEG- Sb₂WO₆, 10 ml PEG- Sb₂WO₆ was 2.78 eV, 2.66 eV and 2.21 eV. The 10 ml PEG assisted sample exhibited narrow bandgap. The Fourier transform infrared spectroscopy (FTIR) spectra of the samples showed metal vibrations and stretching of the water molecules adsorbed. The Raman spectra showed the vibrational modes present in Sb₂WO₆. The morphology was analyzed employing transmission electron microscope (TEM) for all samples. Pristine Sb₂WO₆ showed growth of nanorods with higher dimensions with high agglomeration. 5 ml PEG- Sb₂WO₆ showed the growth of nanorods with lesser agglomeration. 10 ml PEG assisted Sb₂WO₆ exhibited distinct growth of nanorods with no agglomeration on the surface. The elemental composition was examined employing X-ray Photoelectron Spectroscopy. Prepared product photocatalytic behaviour was tested employing Rhodamine B dye degrading. Different catalyst loading were investigated for degrading the toxic pollutants. 0.2 g 10 ml PEG-Sb₂WO₆ showed 81% efficiency on degrading the toxic pollutant from wastewater. The OH radicals are accountable for photocatalytic behaviour of prepared photocatalyst. The 10 ml PEG-Sb₂WO₆ has the good reusability behavior and stable properties after three cycles. The prepared 10 ml PEG- Sb₂WO₆ photocatalyst will be the potential candidate for the remediation of the water treatment.

Investigation of pure and g-C3N4 loaded CdWO4 photocatalytic activity on reducing toxic pollutants

A facile synthesis of pristine and g-C₃N₄ loaded CdWO₄ (Cadmium Tungstate) were reported and analyzed the effect of pollutants removal in wastewater. The samples were characterized and the morphology of the pristine sample showed the nanostructures with high cluster of layer formed. While adding PEG (Polyethylene glycol), the surface has exhibited less agglomeration and in g-C₃N₄ added sample the agglomeration was intensely reduced and nanostructures have been clearly found. Photocatalytic performance on cationic dye was investigated under visible light. The efficiency calculated for g-C₃N₄- CdWO₄ sample was 85% for MB. The C/C₀ plot gives better degradation. The kinetic study revealed pseudo first order reaction. The g-C₃N₄-CdWO₄ sample exhibited higher "k" value which proved best efficiency on removing the pollutant. g-C₃N₄-CdWO₄ sample will make better reduction on toxic pollutants and be a good candidate in futuristic applications. By carbon based derivates inclusion with photo active materials, the morphology and surface area was greatly improved and it enhances activity of host material and it will be the promising material for industrial applications.

Effects of subinhibitory concentrations of chlorhexidine and mupirocin on biofilm formation in clinical meticillin-resistant Staphylococcus aureus

BACKGROUND

The effects of subinhibitory concentrations (sub-MICs) of antibacterial agents on the biofilm-forming ability of Staphylococcus aureus require further study.

AIM

To investigate the effects of sub-MICs of chlorhexidine and mupirocin on biofilm formation in clinical meticillin-resistant Staphylococcus aureus (MRSA) isolates.

METHODS

MRSA isolates were collected from patients with bloodstream infections at a tertiary care hospital. The basal level of biofilm formation and biofilm induction by sub-MICs of chlorhexidine and mupirocin were evaluated by measuring biofilm mass stained with Crystal Violet.

FINDINGS

Of the 112 MRSA isolates tested, 63 (56.3%) and 44 (39.3%) belonged to sequence type (ST)5 and ST72 lineages, respectively, which are the predominant healthcare- and community-associated clones in South Korea. ST5 isolates were more likely to have chlorhexidine MIC ≥4 (73.0% vs 29.5%), resistance to mupirocin (23.8% vs 0%), agr dysfunction (73.0% vs 9.1%), and qacA/B gene (58.7% vs 2.3%) compared to ST72 isolates. The basal level of biofilm formation ability was frequently stronger in ST72 isolates compared to ST5 isolates (77.3% vs 12.7%). Sub-MICs of chlorhexidine and mupirocin promoted biofilm formation in 56.3% and 53.6%, respectively, of all isolates. Biofilm induction was more prevalent in ST5 isolates (85.7% for chlorhexidine, 69.8% for mupirocin) than in ST72 isolates (15.9% for chlorhexidine, 27.3% for mupirocin).

CONCLUSION

Sub-MICs of chlorhexidine and mupirocin promoted biofilm formation in half of the clinical MRSA isolates. Our results suggest that ST5 MRSA biofilm can be induced together with some other bacterial virulent factors following exposure to chlorhexidine, which might confer a survival advantage to this clone in the healthcare environment.

Organic Datura metel Leaf Extract Mediated Inorganic Rare Earth La₂O₃ Nanocrystals Formation

Development of sustainable synthesis of La₂O₃ nanocrystals formation employing Datura metel leaf extract was explored. The obtained nanocrystals were analyzed employing XRD, Raman, PL, FTIR, XPS and TEM characterizations. With increasing incubation and aging, the transformation of La(OH)₃ to LaOOH and metal ellagate complex formation to La₂O₃ nanocrystals formation was observed. The obtained XRD results clearly revealed the transformation of lanthanum hydroxide to lanthanum oxide hydroxide and then to lanthanum oxide nanocrystals formation with 1, 4 and days. The influence of incubation and aging on La₂O₃ nanocrystals formation was discussed. Datura metel leaf extract product mixture over a period of incubation formed pure hexagonal lanthanum oxide nanocrystals.

A novel flexible drill device enabling arthroscopic transosseous repair of Bankart lesions

We have developed a flexible drill device that makes arthroscopic transosseous repair possible, and report preliminary results. Twelve patients with post-traumatic anterior inferior glenohumeral instability were selected.

SURGICAL TECHNIQUE

the flexible drill device is inserted into the shoulder joint through the posterior portal and the guide pipe unit is placed 5mm posterior to the margin of the anterior glenoid rim. The flexible drill is driven through the glenoid with the power drill, creating a hole in the glenoid. A non-absorbable suture is passed through the hole and a sliding knot tying is performed over the capsule and labrum after completing stitches with the suture hook loaded. The same procedures are repeated in the 2, 3 and 4 o'clock positions of the glenoid. There was no recurrence of dislocation at the mean follow-up period of 52.3 months. The mean Rowe score was 89.5.

Structural and toxic effect investigation of vanadium pentoxide

A facile inorganic complex synthesis route has been developed to synthesis V2O5 nanostructures. The effects of varying incubation time on the crystallinity and morphology of the V2O5 phase has been investigated. The obtained XRD result clearly revealed the pure orthorhombic V2O5 crystalline phase. Raman antiphase bridging VO and chaining VO stretching modes peaks at 686 and 521cm(-1) attributed orthorhombic V2O5 characteristics. The V2p3/2 peak at the binding energies of 517eV and V2p1/2 peak at 524eV assigned to V(5+) oxidation state. Bioinspired V2O5 nanostructures as a biocompatible material for anticancer agents show excellent cytotoxicity at higher V2O5 concentration.

Selective inhibition of histone deacetylase 2 induces p53-dependent survivin downregulation through MDM2 proteasomal degradation

In the present study, we found that selective inhibition of histone deacetylase 2 (HDAC2) with small inhibitory RNA (siRNA) induced survivin downregulation in a p53-dependent manner. Interestingly, suberoylanilide hydroxamic acid (SAHA) or knockdown of HDAC2 induced downregulation of Mdm2, a negative regulator of p53, at the protein level. SAHA and/or HDAC2 siRNA increased Mdm2 ubiquitination, and MG132, an inhibitor of proteosome function, prevented HDAC2 inhibition-induced degradation of Mdm2. Clinically, the mRNA levels of HDAC2 and survivin were prominently overexpressed in lung cancer patients compared to normal lung tissues. Silencing of HDAC2 enhanced the cell death caused by ionizing radiation in lung cancer cells. Collectively, our results indicate that selective inhibition of HDAC2 causes survivin downregulation through activation of p53, which is mediated by downregulation of Mdm2. They further suggest that HDAC2 may exert a dominant effect on lung cancer cell survival by sustaining Mdm2-survivin levels.

Heme oxygenase-1 determines the differential response of breast cancer and normal cells to piperlongumine

Piperlongumine, a natural alkaloid isolated from the long pepper, selectively increases reactive oxygen species production and apoptotic cell death in cancer cells but not in normal cells. However, the molecular mechanism underlying piperlongumine-induced selective killing of cancer cells remains unclear. In the present study, we observed that human breast cancer MCF-7 cells are sensitive to piperlongumine-induced apoptosis relative to human MCF-10A breast epithelial cells. Interestingly, this opposing effect of piperlongumine appears to be mediated by heme oxygenase-1 (HO-1). Piperlongumine upregulated HO-1 expression through the activation of nuclear factor-erythroid-2-related factor-2 (Nrf2) signaling in both MCF-7 and MCF-10A cells. However, knockdown of HO-1 expression and pharmacological inhibition of its activity abolished the ability of piperlongumine to induce apoptosis in MCF-7 cells, whereas those promoted apoptosis in MCF-10A cells, indicating that HO-1 has anti-tumor functions in cancer cells but cytoprotective functions in normal cells. Moreover, it was found that piperlongumine-induced Nrf2 activation, HO-1 expression and cancer cell apoptosis are not dependent on the generation of reactive oxygen species. Instead, piperlongumine, which bears electrophilic α,β-unsaturated carbonyl groups, appears to inactivate Kelch-like ECH-associated protein-1 (Keap1) through thiol modification, thereby activating the Nrf2/HO-1 pathway and subsequently upregulating HO-1 expression, which accounts for piperlongumine-induced apoptosis in cancer cells. Taken together, these findings suggest that direct interaction of piperlongumine with Keap1 leads to the upregulation of Nrf2-mediated HO-1 expression, and HO-1 determines the differential response of breast normal cells and cancer cells to piperlongumine.

Comparison of the clinical characteristics of Mycobacterium tuberculosis and nontuberculous mycobacteria patients with joint involvement

Nontuberculous mycobacteria (NTM) joint involvement is rare. However, the incidence of NTM disease is increasing and it is difficult to distinguish NTM from Mycobacterium tuberculosis (MTB). Here, the clinical characteristics of NTM joint involvement were compared with those of MTB. Distal joint involvement and precipitating factors were significantly more frequent for NTM joint infections. Because pathologic findings of NTM and MTB were similar, microbiological investigations are needed.

The utility of the serum heavy/light chain assay as a complementary tool in the monitoring of patients with plasma cell myeloma: a report of three cases

We report three cases of plasma cell myeloma with obscure and discordant data for a monoclonal component. In this study, the results of serum heavy/light chain (sHLC) were retrospectively compared with those of conventional methods during disease monitoring. All three patients achieved a complete response and experienced a relapse during follow-up, and the sHLC ratio allowed early prediction of disease relapse and correlated well with other electrophoretic methods compared with the free light chain ratio. Therefore, we suggest that the sHLC assay may be useful as a complementary tool; it has a good correlation with conventional methods and sensitivity in assessing disease status and treatment response in patients with plasma cell myeloma.

Piperlongumine induces cell death through ROS-mediated CHOP activation and potentiates TRAIL-induced cell death in breast cancer cells

PURPOSE

Piperlongumine (PL) has been shown to selectively induce apoptotic cell death in cancer cells via reactive oxygen species (ROS) accumulation. In this study, we characterized a molecular mechanism for PL-induced cell death.

METHODS

Cell viability and cell death were assessed by MTT assay and Annexin V-FITC/PI staining, respectively. ROS generation was measured using the H2DCFDA. Small interfering RNA (siRNA) was used for suppressing gene expression. The mRNA and protein expression were analyzed by RT-PCR and Western blot analysis, respectively.

RESULTS

We found that PL promotes C/EBP homologous protein (CHOP) induction, which leads to the up-regulation of its targets Bim and DR5. Pretreatment with the ROS scavenger N-acetyl-cysteine abolishes the PL-induced up-regulation of CHOP and its target genes, suggesting an essential role for ROS in PL-induced CHOP activation. The down-regulation of CHOP or Bim with siRNA efficiently attenuates PL-induced cell death, suggesting a critical role for CHOP in this cell death. Furthermore, PL potentiates TRAIL-induced cytotoxicity in breast cancer cells by upregulating DR5, as DR5 knockdown abolished the sensitizing effect of PL on TRAIL responses.

CONCLUSIONS

Overall, our data suggest a new mechanism for the PL-induced cell death in which ROS mediates CHOP activation, and combination treatment with PL and TRAIL could be a potential strategy for breast cancer therapy.

Implications of caspase-dependent proteolytic cleavage of cyclin A1 in DNA damage-induced cell death

Cyclin A1 is an A-type cyclin that directly binds to CDK2 to regulate cell-cycle progression. In the present study, we found that doxorubicin decreased the expression of cyclin A1 at the protein level in A549 lung cancer cells, while markedly downregulating its mRNA levels. Interestingly, doxorubicin upregulated caspase-1 in a concentration-dependent manner, and z-YAVD-fmk, a specific inhibitor of caspase-1, reversed the doxorubicin-induced decrease in cyclin A1 in A549 lung cancer and MCF7 breast cancer cells. Active caspase-1 effectively cleaved cyclin A1 at D165 into two fragments, which in vitro cleavage assays showed were further cleaved by caspase-3. Finally, we found that overexpression of cyclin A1 significantly reduced the cytotoxicity of doxorubicin, and knockdown of cyclin A1 by RNA interference enhanced the sensitivity of cells to ionizing radiation. Our data suggest a new mechanism for the downregulation of cyclin A1 by DNA-damaging stimuli that could be intimately involved in the cell death induced by DNA damage-inducing stimuli, including doxorubicin and ionizing radiation.

Novel green synthetic strategy to prepare ZnO nanocrystals using rambutan (Nephelium lappaceum L.) peel extract and its antibacterial applications

In the present investigation, we report a sustainable novel green synthetic strategy to synthesis zinc oxide nanocrystals. This is the first report on sustainable biosynthesis of zinc oxide nanocrystals employing Nephelium lappaceum L., peel extract as a natural ligation agent. Green synthesis of zinc oxide nanocrystals was carried out via zinc-ellagate complex formation using rambutan peel wastes. The successful formation of zinc oxide nanocrystals was confirmed employing standard characterisation studies. A possible mechanism for the formation of ZnO nanocrystals with rambutan peel extract was also proposed. The prepared ZnO nanocrystals were coated on the cotton fabric and their antibacterial activity were analyzed. ZnO nanocrystals coated cotton showed good antibacterial activity towards Escherichia coli (E. coli), gram negative bacteria and Staphylococcus aureus (S. aureus), gram positive bacteria.

Comparison of the serum fibrin-fibrinogen degradation products with cytokeratin 19 fragment as biomarkers in patients with lung cancer

Lung cancer is one of the main causes of cancer-related mortality. The identification of early diagnostic biomarkers improved outcomes for lung cancer patients. Serum fibrin-fibrinogen degradation products (FDP) levels are elevated in numerous malignancies due to hemostatic alterations. The serum FDP levels were compared to the levels of cytokeratin 19 fragment antigen (CYFRA 21-1), another well-established biomarker. The serum samples from 193 lung cancer patients, 84 healthy controls and 106 patients with benign respiratory diseases were obtained. The serum FDP level was measured using the DR-70 immunoassay and the CYFRA 21-1 level was measured by electrochemiluminescence using the Roche Analytics E170. Receiver operating characteristics curves were used to assess the predictive sensitivity and specificity. The mean serum FDP level in lung cancer patients (35.01±229.02 μg/ml) was significantly higher compared to the 190 non-cancerous subjects (0.60±0.75 μg/ml; P=0.039). The mean serum CYFRA 21-1 level in lung cancer patients (4.50±6.67 ng/ml) was also significantly higher compared to the non-cancerous subjects (1.40±0.83 ng/ml; P<0.05). FDP exhibited clinical sensitivity and specificity of 86 and 75%, respectively, at an optimal cut-off at 0.67 μg/ml. CYFRA 21-1 exhibited clinical sensitivity and specificity of 77 and 74%, respectively, at a cut-off of 1.65 ng/ml. The serum FDP area under the curve (0.87) was slightly higher compared to CYFRA 21-1 (0.83). Therefore, it is apparent that serum FDP is comparable to CYFRA 21-1 as a lung cancer biomarker and can be used for clinical practice.

Sustained overexpression of Redd1 leads to Akt activation involved in cell survival

Herein, we show that the constitutive overexpression of Redd1, a negative regulator of mTORC1, induces Akt activation in lung cancer cells. Akt phosphorylation was reduced to basal levels by Rictor siRNA, suggesting the involvement of mTORC2 in this process. Perifosine and PP242, selective inhibitors of Akt and mTORC1/2, respectively, efficiently suppressed the Akt phosphorylation that was induced by the sustained overexpression of Redd1 and increased the sensitivity of the cells to cisplatin. Therefore, the sustained overexpression of Redd1 leads to mTORC1 inhibition and to consequent Akt activation that is involved in cell survival. This finding highlights the importance of Akt activation as a therapeutic target to overcome resistance to chemotherapy.

Clinical utility of the Xpert MRSA assay for early detection of methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for many nosocomial and community-acquired infections, resulting in significant morbidity and mortality. A practical way to limit the spread of MRSA is early detection and proper treatment. However, screening culture for MRSA typically requires 2-3 days. The Xpert MRSA assay (Cepheid, Sunnyvale, CA, USA) is a real-time polymerase chain reaction-based assay developed for screening an MRSA-specific DNA sequence within the staphylococcal cassette chromosome in 2 h. Lower respiratory tract specimens, such as transtracheal aspirates (TTAs) and bronchoalveolar lavage fluid (BALF), are commonly obtained from intubated patients. Therefore, using the lower respiratory tract specimens with the Xpert MRSA assay may be a practical tool for patient care. We performed the Xpert MRSA assay on 108 TTA and 21 BALF specimens from 92 patients and compared the results to those obtained by culture. The two assays showed concordant results in 120 (93.0%) cases and discordant results in 9 (7.0%) cases, which were culture‑negative and Xpert MRSA-positive. Among the discordant cases, 5 patients developed culture-positive samples 2-15 days after the Xpert MRSA detected MRSA. We conclude that the Xpert MRSA assay is a rapid, sensitive and clinically useful test, particularly for the early detection of MRSA.

Redd1 inhibits the invasiveness of non-small cell lung cancer cells

Redd1 acts as a negative regulator of mTOR in response to various stress conditions, but its specific physiological role is currently unclear. In the present study, we showed that Redd1 inhibits the invasive activity of non-small cell lung cancer (NSCLC) cells. Interestingly, expression of Redd1 was extremely low in H1299 cells displaying high invasiveness, compared with that in H460 cells with lower invasive activity. Overexpression of Redd1 inhibited the invasive activity of H1299 cells, while suppression with specific siRNAs enhanced the invasiveness of H460 cells. Knockdown of the mTOR downstream substrate, S6K, resulted in a decrease in the invasive property of H1299 cells. Our results provide preliminary evidence that Redd1 inhibits the invasive activity of NSCLC cells via suppression of the mTOR downstream pathway.

[Development of indicators to assess the stability of remnant blood samples stored in a biobank: experience at one institution]

BACKGROUND

One of the major concerns with biobanking is the absence of standard operating procedures to eliminate pre-analytical variation arising from sample collection, preparation, and storage. Currently, there is a lack of tools to carry out quality control procedures for stored blood samples. The aim of this study is to assess the quality of stored blood samples in our biobank and to suggest appropriate indicators for their quality control.

METHODS

The stored blood samples that we tested have been registered into our biobank since 2003. These were transferred to our biobank after carrying out routine requested tests, because the samples would have otherwise been discarded. For the purpose of quality control, we analyzed the concentrations and the integrity of DNA and RNA extracted from the stored samples and tested the levels of several serum proteins; the results were compared with the corresponding pre-storage levels.

RESULTS

A total of 19 samples were stored from 2006 to 2009. Of the 22 samples stored between 2003 and 2005, 50% showed complete DNA integrity. However, sufficient RNA integrity was noted in only 1 sample stored as recently as 2009. High blood urea nitrogen levels were also noted in the stored sera, but the increase did not correlate to the duration of storage.

CONCLUSIONS

The amount and integrity of nucleic acids extracted from stored blood samples are potential indicators that can be used for quality control. A guideline for the quality assessment of stored blood samples in a biobank is urgently needed.

Low doses of ionizing radiation suppress doxorubicin-induced senescence-like phenotypes by activation of ERK1/2 and suppression of p38 kinase in MCF7 human breast cancer cells

Low-dose radiation has a variety of effects on cellular activities, including the cell division cycle, apoptosis, proliferation and senescence. However, the effects of low doses of radiation remain controversial. In this study, we examined the effects of low-dose radiation on cellular senescence. We treated MCF7 cells with 0.01 microg/ml doxorubicin to induce replicative senescence, 2 h after exposure to low doses of ionizing radiation of 0.05, 0.1, or 0.2 Gy. The status of p53, senescence-associated beta-galactosidase activity, p38 kinase levels, H2AX levels and ERK/MAPK levels were examined. Low doses of ionizing radiation inhibit doxorubicin-induced senescence in human breast cancer MCF7 cells. The phosphorylations of both p38 MAP kinase and p53 induced by doxorubicin were suppressed by low doses of ionizing radiation. The senescence was inhibited without genomic damage, because the level of gamma-H2AX protein was not changed. Moreover, low doses of ionizing radiation inhibited senescence through the activation of ERK1/2. The results thus suggest that low doses of radiation suppress doxorubicin-induced replicative senescence through the inhibition of p38-dependent phosphorylation of p53 and by activation of ERK1/2, without genomic damage. Overall, our results suggest that low doses of ionizing radiation may have a protective role against replicative senescence induced by doxorubicin.

Abstract 297: Activating transcription factor 4 negatively regulates the mammalian target of rapamycin via Redd1 expression in response to 2-deoxyglucose

Aerobic glycolysis is one of major metabolic changes found in cancer cells and is a valid target for cancer therapy. The nonmetabolizable glucose analogue, 2-deoxyglucose (2-DG) interferes with glucose metabolism and enhances chemotherapy/radiotherapy in cancer cells. We have investigated the mechanism of action by which 2-DG inhibits mammalian target of rapamycin (mTOR) activity. We found that 2-DG treatment led to decreased mTOR activity which was regulated by induction of Redd1 protein in both lung cancer cells and cervical cancer cells. We also found 2-DG treatment led to increased ATF4 protein expression and transcriptional activity. Suppression of ATF4 using siRNAs led to decrease of 2-DG induced Redd1 expression. Our data suggested that 2-DG induced Redd1 expression is regulated by the ATF4, leading to mTOR inhibition.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 297.

[HDL cholesterol reduction during rosiglitazone and fenofibrate treatment in a type 2 diabetes mellitus patient with dyslipidemia]

Thiazolidinediones (TZD), which are widely used as insulin sensitizers, and fibrates, which are lipid-lowering drugs, are used in the treatment of dyslipidemia that commonly accompanies diabetes. Several reports suggest elevated levels of high-density lipoprotein (HDL) cholesterol, but the paradoxical reduction of HDL cholesterol level during single or combined TZD and fibrate therapies has been occasionally reported. Herein, we report a case of paradoxical decrease in HDL cholesterol and apolipoprotein A-1 levels during rosiglitazone and fenofibrate treatment for the first time in Korea. The patient was a 56-yr-old man presenting with type 2 diabetes mellitus and dyslipidemia. His HDL cholesterol and apolipoprotein A-1 levels returned to normal after the cessation of fenofibrate therapy. Since diabetes is an established risk factor of cardiovascular diseases, low HDL cholesterol can be a key cause of concern for patients with diabetes. Therefore, HDL cholesterol level should be determined before and after starting TZD and/or fibrate therapy in diabetic patients.

Nuclear protein 1 induced by ATF4 in response to various stressors acts as a positive regulator on the transcriptional activation of ATF4

Nuclear protein 1 (NUPR1) was originally identified as p8, a member of the family of HMG-I/Y transcription factors induced in response to various cellular stressors. However, the signaling pathway underlying NUPR1 induction by cellular stresses remains to be established. In this study, we found that the expression of NUPR1 by various stresses induced by activating transcription factor 4 (ATF4). Loss of ATF4 using siRNA significantly diminished NUPR1 expression. Overexpression of ATF4 caused NUPR1 levels to rise. NUPR1 expression was associated with enhanced transcriptional activation of genes of ATF4 downstream, suggesting that the protein promoted the transcription of stress-regulated genes via positive feedback on the ATF4 pathway.

[Near-tetraploidy acute myeloid leukemia with RUNX1-RUNX1T1 rearrangement due to cryptic t(8;21)]

Tetraploidy or near-tetraploidy is a rare cytogenetic abnormality found in AML, and is divided into primary and secondary forms. The secondary tetraploidy or near-tetraploidy found in AML is known to be specifically associated with t(8;21). In this case report, FISH analysis detected RUNX1-RUNX1T1 gene rearrangement in the absence of cytogenetic abnormality of t(8;21), which suggests the presence of unvailed t(8;21). This is the first case report of tetraploidy or near-tetraploidy AML with cryptic RUNX1/RUNX1T1 in Korea. Although the prognosis of tetraploidy or near- tetraploidy with t(8;21) is known to be poor, this patient shows a relatively good clinical course compared to other reported cases.

A truncated form of p23 down-regulates telomerase activity via disruption of Hsp90 function

The Hsp90-associated protein p23 modulates Hsp90 activity during the final stages of the chaperone pathway to facilitate maturation of client proteins. Previous reports indicate that p23 cleavage induced by caspases during cell death triggers destabilization of client proteins. However, the specific role of truncated p23 (Delta p23) in this process and the underlying mechanisms remain to be determined. One such client protein, hTERT, is a telomerase catalytic subunit regulated by several chaperone proteins, including Hsp90 and p23. In the present study, we examined the effects of p23 cleavage on hTERT stability and telomerase activity. Our data showed that overexpression of Delta p23 resulted in a decrease in hTERT levels, and a down-regulation in telomerase activity. Serine phosphorylation of Hsp90 was significantly reduced in cells expressing high levels of Delta p23 compared with those expressing full-length p23. Mutation analyses revealed that two serine residues (Ser-231 and Ser-263) in Hsp90 are important for activation of telomerase, and down-regulation of telomerase activity by Delta p23 was associated with inhibition of cell growth and sensitization of cells to cisplatin. Our data aid in determining the mechanism underlying the regulation of telomerase activity by the chaperone complex during caspase-dependent cell death.

Cathepsin D and eukaryotic translation elongation factor 1 as promising markers of cellular senescence

Induction of premature senescence may be a promising strategy for cancer treatment. However, biomarkers for senescent cancer cells are lacking. To identify such biomarkers, we performed comparative proteomic analysis of MCF7 human breast cancer cells undergoing cellular senescence in response to ionizing radiation (IR). IR-induced senescence was associated with up-regulation of cathepsin D (CD) and down-regulation of eukaryotic translation elongation factor 1beta2 (eEF1B2), as confirmed by Western blot. The other elongation factor, eukaryotic translation elongation factor 1alpha1 (eEF1A1), was also down-regulated. IR-induced senescence was associated with similar changes of CD and eEF1 (eEF1A1 and eEF1B2) levels in the HCT116 colon cancer cell line and the H460 lung cancer cell line. Up-regulation of CD and down-regulation of eEF1 seemed to be specific to senescence, as they were observed during cellular senescence induced by hydrogen peroxide or anticancer drugs (camptothecin, etoposide, or 50 ng doxorubicin) but not during apoptosis induced by Taxol or 10 microg doxorubicin or autophagy induced by tamoxifen. The same alterations in CD and eEF1A1 levels were observed during replicative senescence and Ras oncogene-induced senescence. Transient cell cycle arrest did not alter levels of eEF1 or CD. Chemical inhibition of CD (pepstatin A) and small interfering RNA-mediated knockdown of CD and eEF1 revealed that these factors participate in cell proliferation. Finally, the senescence-associated alteration in CD and eEF1 levels observed in cell lines was also observed in IR-exposed xenografted tumors. These findings show that CD and eEF1 are promising markers for the detection of cellular senescence induced by a variety of treatments.

Heterogeneity of Capillary Endothelial Cells for Basic Fibroblast Growth Factor-Induced Paracrine Signaling

In this study, the authors isolated morphologically different capillary endothelial cells, designated as BCE-1 and BCE-2 cells, from bovine adrenal cortex. By a series of experiments involving proliferation, migration, and tubular-like structure formation assays, the authors found that the two BCE clones showed a clearly different response to basic fibroblast growth factor (bFGF). Similar to these results, the ERK-1/2 in the BCE-1 cells was phosphorylated by bFGF or vascular endothelial growth factor (VEGF), whereas that of the BCE-2 cells was phosphorylated only by VEGF. However, when the BCE-2 cells were transfected with FGF receptor 1 cDNA, the ERK-1/2 of these cells was phosphorylated by exogenous bFGF. Receptor binding experiments revealed that BCE-2 cells expressed high-affinity tyrosine-kinase FGF receptors approximately twofold less than BCE-1 cells. Transfection and receptor binding studies suggest a possibility that the poor response of the BCE-2 cells to exogenous bFGF is derived from the limitation of functional availability of high affinity FGF receptors. On the other hand, when both BCE clones were treated with anti-bFGF antibodies, basal formation of tubular-like structure in both clones were strongly inhibited, indicating that endogenous bFGF plays a role in in vitro angiogenesis of both BCE clones. Taken together, these data show that the isolated capillary endothelial cells are heterogeneous for paracrine but not autocrine bFGF signaling, and suggest that the diversity of capillary endothelial cells can occur by angiogenic factors, such as bFGF.

Activating transcription factor 4 and CCAAT/enhancer-binding protein-beta negatively regulate the mammalian target of rapamycin via Redd1 expression in response to oxidative and endoplasmic reticulum stress

Regulation of mRNA translation in mammalian cells involves the coordinated control of mammalian target of rapamycin (mTOR) signaling. At present, limited information is available on the potential relevance of mTOR regulation, although translation inhibition during oxidative and endoplasmic reticulum (ER) stress is clearly important. In this study, we show that activating transcription factor 4 (ATF4) and CCAAT/enhancer-binding protein-beta (C/EBP-beta) negatively regulate mTOR via Redd1 expression in response to oxidative and ER stress. Oxidative and ER stress conditions induce rapid and significant activation of ATF4 downstream of eIF2alpha phosphorylation, which is responsible for Redd1 expression. In our experiment, overexpression of ATF4 was associated with reduced mTOR activity via Redd1 expression, whereas suppression of ATF4 levels with small interfering RNA led to the recovery of decreased mTOR activity mediated by downregulation of Redd1 during oxidative and ER stress. We additionally identified Redd1 as a downstream effector of C/EBP-beta stimulated by ATF4 activated under the stress conditions examined. RNA interference studies provided further evidence of the requirement of C/EBP-beta for Redd1 expression. We conclude that the Redd1 gene is transactivated by the ATF4 and C/EBP family of transcription factors, leading to mTOR inhibition in response to oxidative and ER stress.

Ultrastructural observation of electron irradiation damage of lamellar bone

The ultrastructure of murine femoral lamellar bone and the effect of electron irradiation (200 kV) on collagen and mineral features were investigated using in situ high resolution transmission electron microscopy (HRTEM). Bands of collagen fibrils were mostly aligned parallel to the long axis of the bones, with some bands of fibrils inclined in longitudinal sections. The similarity of the ultrastructure between the longitudinal and transverse sections supports the rotated plywood structure of the lamellar bone. The collagen fibrils appeared damaged and the mineral crystals were coarsened after electron irradiation. Continuous diffraction rings became spotty and the contrast between rings and the background became sharper, further suggesting coarsening of apatite crystals and increased crystallinity after irradiation. No new phases were observed after irradiation. Both the damage to collagen and coarsening of apatite crystals can deteriorate the strength and integrity of bone, and may provide insight into fracture in patients who have undergone radiation therapy.

Activation of epidermal growth factor receptor and its downstream signaling pathway by nitric oxide in response to ionizing radiation

Epidermal growth factor receptor (EGFR) is activated by ionizing radiation (IR), but the molecular mechanism for this effect is unknown. We have found that intracellular generation of nitric oxide (NO) by NO synthase (NOS) is required for the rapid activation of EGFR phosphorylation by IR. Treatment of A549 lung cancer cells with IR increased NOS activity within minutes, accompanied by an increase of NO. 2-Phenyl-4,4,5,5,-tetramethylimidazolline-1-oxyl-3-oxide, an NO scavenger, and NG-monomethyl-l-arginine, an NOS inhibitor, abolished the increase in intracellular NO and activation of EGFR by IR. In addition, an NO donor alone induced EGFR phosphorylation. Transient transfection with small interfering RNA for endothelial NOS reduced IR-induced NO production and suppressed IR-induced EGFR activation. Overexpression of endothelial NOS increased IR-induced NO generation and EGFR activation. These results indicate a novel molecular mechanism for EGFR activation by IR-induced NO production via NOS.

Combined effects of sulindac and suberoylanilide hydroxamic acid on apoptosis induction in human lung cancer cells

Histone deacetylase (HDAC) inhibitors represent a promising group of anticancer agents. Treatment of cancer cells with HDAC blockers, such as suberoylanilide hydroxamic acid (SAHA), leads to the activation of apoptosis-promoting genes. To enhance proapoptotic efficiency, SAHA has been used in conjunction with radiation, kinase inhibitors, and cytotoxic drugs. In the present study, we show that at the suboptimal dose of 250 muM, sulindac [2-[6-fluoro-2-methyl-3-[(4-methylsulfinylphenyl)methylidene]inden-1-yl]-acetic acid] significantly enhances SAHA-induced growth suppression and apoptosis of A549 human non-small cell lung cancer cells, primarily via enhanced collapse of the mitochondrial membrane potential, release of cytochrome c, and caspase activation. Furthermore, sulindac/SAHA cotreatment induced marked down-regulation of survivin at both the mRNA and protein levels and stimulated the production of reactive oxygen species (ROS), which were blocked by the antioxidant N-acetyl-l-cysteine. Overexpression of survivin was associated with reduced sulindac/SAHA-induced apoptosis of A549 cells, whereas suppression of survivin levels with antisense oligonucleotides or small interfering RNA further sensitized cells to sulindac/SAHA-induced cell death. Our results collectively demonstrate that sulindac/SAHA-induced apoptosis is mediated by ROS-dependent down-regulation of survivin in lung cancer cells.

Ionizing radiation enhances matrix metalloproteinase-2 secretion and invasion of glioma cells through Src/epidermal growth factor receptor-mediated p38/Akt and phosphatidylinositol 3-kinase/Akt signaling pathways

Glioblastoma is a severe type of primary brain tumor, and its highly invasive character is considered to be a major therapeutic obstacle. Several recent studies have reported that ionizing radiation (IR) enhances the invasion of tumor cells, but the mechanisms for this effect are not well understood. In this study, we investigated the possible signaling mechanisms involved in IR-induced invasion of glioma cells. IR increased the matrix metalloproteinase (MMP)-2 promoter activity, mRNA transcription, and protein secretion along with the invasiveness of glioma cells lacking functional PTEN (U87, U251, U373, and C6) but not those harboring wild-type (WT)-PTEN (LN18 and LN428). IR activated phosphatidylinositol 3-kinase (PI3K), Akt, and mammalian target of rapamycin, and blockade of these kinases by specific inhibitors (LY294002, Akt inhibitor IV, and rapamycin, respectively) and transfection of dominant-negative (DN) mutants (DN-p85 and DN-Akt) or WT-PTEN suppressed the IR-induced MMP-2 secretion in U251 and U373 cells. In addition, inhibitors of epidermal growth factor receptor (EGFR; AG490 and AG1478), Src (PP2), and p38 (SB203580), EGFR neutralizing antibody, and transfection of DN-Src and DN-p38 significantly blocked IR-induced Akt phosphorylation and MMP-2 secretion. IR-induced activation of EGFR was suppressed by PP2, whereas LY294002 and SB203580 did not affect the activations of p38 and PI3K, respectively. Finally, these kinase inhibitors significantly reduced the IR-induced invasiveness of these cells on Matrigel. Taken together, our findings suggest that IR induces Src-dependent EGFR activation, which triggers the p38/Akt and PI3K/Akt signaling pathways, leading to increased MMP-2 expression and heightened invasiveness of PTEN mutant glioma cells.

Nerve growth factor induces endothelial cell invasion and cord formation by promoting matrix metalloproteinase-2 expression through the phosphatidylinositol 3-kinase/Akt signaling pathway and AP-2 transcription factor

Nerve growth factor (NGF) is a well characterized neurotrophic agonist in the nervous system that triggers angiogenesis. In this study, we investigated the signaling mechanisms involved in NGF-induced angiogenesis. NGF stimulated endothelial cell invasion and cord formation on Matrigel in vitro but had marginal effect on proliferation and migration of these cells. NGF stimulated matrix metalloproteinase (MMP)-2 mRNA expression and protein secretion in human umbilical vein endothelial cells. Using synthetic and endogenous inhibitors of MMP-2 and MMP-2 small interfering RNA suppressed NGF-induced invasion and cord formation. We demonstrated that NGF-induced MMP-2 secretion, invasion, and cord formation are regulated via activation of the NGF receptor, TrkA, phosphatidylinositol 3-kinase (PI3K), and Akt using various pharmacological inhibitors. Specifically, NGF enhanced TrkA phosphorylation, PI3K activity, and Akt phosphorylation. Introduction of NGF-neutralizing antibodies, dominant-negative Akt, or wild-type PTEN effectively inhibited NGF-induced MMP-2 secretion and cord formation. Deletion and site-directed mutagenesis analysis of the MMP-2 promoter demonstrated that the AP-2-binding site is critical for NGF-induced MMP-2 promoter activity. NGF increased the DNA binding activity of AP-2, which was suppressed by inhibitors of TrkA and PI3K. Furthermore, transfection of AP-2 small interfering RNA effectively blocked NGF-induced MMP-2 secretion and cord formation. Finally, NGF promoted neovessel formation in Matrigel plugs in vivo, which was significantly inhibited by K252a and LY294002, but it failed to promote angiogenesis using MMP-2 knock-out mice. Our data collectively suggest that NGF stimulates endothelial cell invasion and cord formation by augmenting MMP-2 via the PI3K/Akt signaling pathway and AP-2 transcription factor, which may be responsible for triggering angiogenesis.

Enhanced wear and fatigue properties of Ti-6Al-4V alloy modified by plasma carburizing/CrN coating

In this study, a newly developed duplex coating method incorporating plasma carburization and CrN coating was applied to Ti-6Al-4V and its effects on the wear resistance and fatigue life were investigated. The carburized layer with approximately150 microm in depth and CrN coating film with 7.5 microm in thickness were formed after duplex coating. Hard carbide particles such as TiC And V(4)C(3) were formed in the carburized layer. XRD diffraction pattern analysis revealed that CrN film had predominant [111] and [200] textures. The hardness (Hv) was significantly improved up to about 1,960 after duplex coating while the hardness value of original Ti-6Al-4V was 402. The threshold load for the modification and/or failure of CrN coating was measured to be 32 N using the acoustic emission technique. The wear resistance and fatigue life of duplex-coated Ti-6Al-4V improved significantly compared to those of un-treated specimen. The enhanced wear resistance can be attributed to the excellent adhesion and improved hardness of CrN coating film for the duplex-coated Ti-6Al-4V. The initiation of fatigue cracks is likely to be retarded by the presence of hard and strong layers on the surface, resulting in the enhanced fatigue life.

Hypoxic condition- and high cell density-induced expression of Redd1 is regulated by activation of hypoxia-inducible factor-1alpha and Sp1 through the phosphatidylinositol 3-kinase/Akt signaling pathway

Redd1, a recently discovered stress-response gene, is regulated by hypoxia via hypoxia-inducible factor 1 (HIF-1) and by DNA damage via p53/p63; however, the signaling pathway by which its expression is induced by hypoxia has not been elucidated. In the present study, we demonstrated that the expression of Redd1 in response to hypoxia (1% O(2)), hypoxia-mimetic agent, cobalt chloride (CoCl(2)) and high cell density (HCD) requires coactivation of HIF-1alpha and Sp1. CoCl(2) and HCD induced the activation of HIF-1alpha and Sp1 in HeLa cells, and siRNAs targeting HIF-1alpha and Sp1 abrogated Redd1 expression. Inhibition of phosphatidylinositol 3-kinase (PI3K) by LY294002 and by a dominant-negative PI3K mutant reduced the expression of Redd1 and activation of HIF-1alpha and Sp1 by CoCl(2) and HCD. Also, suppression of Akt activation blocked the expression of Redd1 and the activation of HIF-1alpha and Sp1 by CoCl(2) and HCD. Furthermore, we found that the induction of Redd1 expression by CoCl(2) can be mediated by activation of Sp1 in HIF-1alpha-deficient cells but that a higher level of Redd1 expression is achieved when these cells are transfected with HIF-1alpha. These results demonstrate that hypoxic condition-and HCD-induced expression of Redd1 is mediated by coactivation of Sp1 and HIF-1alpha downstream of the PI3K/Akt signaling pathway.

Production of penicillic acid by Aspergillus sclerotiorum CGF

The production of penicillic acid by Aspergillus sclerotiorum CGF for the biocontrol of Phytophthora disease was investigated in submerged fermentation using media composed of different nutrients. Soluble starch was found to be the most effective substrate among the carbon sources used, and produced the highest penicillic acid concentration of 2.98 mg ml(-1). When organic nitrogen sources were used, pharmamedia, yeast extract, and polypeptone-S were found to be suitable organic nitrogen sources (2.46-2.71 mg ml(-1)). The production of penicillic acid was not detected in when inorganic nitrogen sources were used. Only Na2HPO4, among the metal ions and phosphate salts tested, increased the production of penicillic acid (approximately 20%). When A. sclerotiorum CGF was cultured in optimal medium [8.0% (w/v) soluble starch, 0.6% (w/v) yeast extract, and 0.3% (w/v) Na2HPO4], maximum penicillic acid concentration (approximately 9.40 mg ml(-1)) and cell mass (approximately 17.4 g l(-1)) were obtained after 12 days.

Sulindac-derived reactive oxygen species induce apoptosis of human multiple myeloma cells via p38 mitogen activated protein kinase-induced mitochondrial dysfunction

Non-steroidal anti-inflammatory drugs are well known to induce apoptosis of cancer cells independent of their ability to inhibit cyclooxygenase-2, but the molecular mechanism for this effect has not yet been fully elucidated. The purpose of this study was to elucidate the potential signaling components underlying sulindac-induced apoptosis in human multiple myeloma (MM) cells. We found that sulindac induces apoptosis by promoting ROS generation, accompanied by opening of mitochondrial permeability transition pores, release of cytochrome c and apoptosis inducing factor from mitochondria, followed by caspase activation. Bcl-2 cleavage and down-regulation of the inhibitor of apoptosis proteins (IAPs) family including cIAP-1/2, XIAP, and survivin, occurred downstream of ROS production during sulindac-induced apoptosis. Forced expression of survivin and Bcl-2 blocked sulindac-induced apoptosis. Most importantly, sulindac-derived ROS activated p38 mitogen-activated protein kinase and p53. SB203580, a p38 mitogen-activated protein kinase inhibitor, and RNA inhibition of p53 inhibited the sulindac-induced apoptosis. Furthermore, p53, Bax, and Bak accumulated in mitochondria during sulindac-induced apoptosis. All of these events were significantly suppressed by SB203580. Our results demonstrate a novel mechanism of sulindac-induced apoptosis in human MM cells, namely, accumulation of p53, Bax, and Bak in mitochondria mediated by p38 MAPK activation downstream of ROS production.

Synergistic induction of apoptosis by sulindac and arsenic trioxide in human lung cancer A549 cells via reactive oxygen species-dependent down-regulation of survivin

Survivin, a member of the inhibitor of apoptosis protein (IAP) family, may be a good target for cancer therapy because it is expressed in a variety of human tumors but not in differentiated adult tissues. In the present study, we show that a combination of sulindac and arsenic trioxide (ATO) induces more extensive apoptosis than either drug alone in A549 human non-small cell lung carcinoma (NSCLC) cells. Treatment with sulindac/ATO reduced the expression of survivin and promoted major apoptotic signaling events, namely, collapse of the mitochondrial membrane potential, release of cytochrome c, and activation of caspases. Combined sulindac/ATO treatment did not significantly affect the levels of other members of the IAP family (XIAP, cIAP1 and cIAP2), indicating that the effects were specific to survivin. In addition, sulindac/ATO treatment induced the production of reactive oxygen species and the antioxidant N-acetyl-l-cysteine blocked the down-regulation of survivin and induction of apoptotic signaling by the combination of sulindac and ATO. Combined sulindac/ATO treatment also activated p53 expression, and inhibition of p53 expression by small interfering RNA (siRNA) prevented sulindac/ATO-induced down-regulation of survivin, suggesting that survivin expression is negatively regulated by p53. Overexpression of survivin reduced sulindac/ATO-induced apoptosis in A549 cells and reduction of survivin levels by siRNA sensitized the cells to sulindac/ATO-induced cell death. These results demonstrate that, in A549 human NSCLC cells, sulindac/ATO-induced apoptosis is mediated by the reactive oxygen species-dependent down-regulation of survivin.

Emodin inhibits vascular endothelial growth factor-A-induced angiogenesis by blocking receptor-2 (KDR/Flk-1) phosphorylation

Emodin (1,3,8-trihydroxy-6-methylanthraquinone), an active component in the root and rhizome of Rheum palmatum, is a tyrosine kinase inhibitor with a number of biological activities, including antitumor effects. Here, we examine the effects of emodin on vascular endothelial growth factor (VEGF)-A-induced angiogenesis, both in vitro and in vivo. In vitro, emodin dose-dependently inhibits proliferation, migration into the denuded area, invasion through a layer of Matrigel and tube formation of human umbilical vein endothelial cells (HUVECs) stimulated with VEGF-A. Emodin also inhibits basic fibroblast growth factor-induced proliferation and migration of HUVECs and VEGF-A-induced tube formation of human dermal microvascular endothelial cells. Specifically, emodin induces the cell cycle arrest of HUVECs in the G0/G1 phase by suppressing cyclin D1 and E expression and retinoblastoma protein phosphorylation, and suppresses Matrigel invasion by inhibiting the basal secretion of matrix metalloproteinase-2 and VEGF-A-stimulated urokinase plasminogen activator receptor expression. Additionally, emodin effectively inhibits phosphorylation of VEGF-A receptor-2 (KDR/Flk-1) and downstream effector molecules, including focal adhesion kinase, extracellular signal-regulated kinase 1/2, p38 mitogen-activated protein kinase, Akt and endothelial nitric oxide synthase. In vivo, emodin strongly suppresses neovessel formation in the chorioallantoic membrane of chick and VEGF-A-induced angiogenesis of the Matrigel plug in mice. Our data collectively demonstrate that emodin effectively inhibits VEGF-A-induced angiogenesis in vitro and in vivo. Moreover, inhibition of phosphorylation of KDR/Flk-1 and downstream effector molecules is a possible underlying mechanism of the anti-angiogenic activity of emodin. Based on these data, we propose that an interaction of emodin with KDR/Flk-1 may be involved in the inhibitory function of emodin toward VEGF-A-induced angiogenesis in vitro and responsible for its potent anti-angiogenic in vivo.

Transforming Growth Factor-β1 Induces Tissue Inhibitor of Metalloproteinase-1 Expression via Activation of Extracellular Signal-Regulated Kinase and Sp1 in Human Fibrosarcoma Cells

The net balance of matrix metalloproteinases (MMP) and tissue inhibitor of metalloproteinases (TIMP) system has been known to be a key factor in tumor cell invasion. In the present study, we investigated the molecular mechanisms of anti-invasive and antimigrative activity of transforming growth factor (TGF)-beta1 on HT1080 human fibrosarcoma cells. In in vitro Matrigel invasion and Transwell migration assays, TGF-beta1 dose-dependently inhibited the invasion and migration of HT1080 cells, respectively. Gelatin zymography, Western blot, and real-time PCR analysis showed that TGF-beta1 enhanced the expression and secretion of MMP-2, TIMP-1, and, to a lesser degree, MMP-9 but not membrane type 1-MMP and TIMP-2. The addition of recombinant TIMP-1 protein reduced the Matrigel invasion and Transwell migration of HT1080 cells, similar to TGF-beta1. Because augmentation of TIMP-1 might be the major factor for the anti-invasive and antimigrative activity of TGF-beta1, we investigated possible molecular mechanisms responsible for the expression of TIMP-1 induced by TGF-beta1. Treatment of HT1080 cells with TGF-beta1 rapidly phosphorylated three mitogen-activated protein kinases [MAPK; extracellular signal-regulated kinase 1/2 (ERK1/2), p38, and c-Jun NH2-terminal kinase] and Akt. Among these kinases, the inhibition of only ERK1/2 pathway by PD98059, a specific inhibitor of MAPK/ERK kinase(MEK)-1, and transfection of dominant-negative MEK 1 effectively blocked the TIMP-1 induction by TGF-beta1. Mithramycin, a specific inhibitor of Sp1 transcription factor, but not curcumin, an inhibitor of activator protein-1, and transfection of Sp1 small interfering RNA significantly inhibited the TGF-beta1-induced expression of TIMP-1. In addition, electrophoretic mobility shift assay showed that TGF-beta1 up-regulated Sp1 DNA-binding activity, and PD98059 and mithramycin effectively inhibited these events. Finally, pretreatment of HT1080 cells with PD98059 and mithramycin, but not curcumin, restored the invasive activity of these cells. Taken together, these data suggest that TGF-beta1 modulates the net balance of the MMPs/TIMPs the systems in HT1080 cells for anti-invasion and antimigration by augmenting TIMP-1 through ERK1/2 pathway and Sp1 transcription factor.