Characterization of the adsorption of Ru-bpy dyes on mesoporous TiO2 films with UV-Vis, Raman, and FTIR spectroscopies

In the present work the adsorption of a new dye, [Ru(dcbpyH(2))(2)(bpy-TPA(2))](PF(6))(2), and the well-known (Bu(4)N)(2)[Ru(dcbpyH)(2)(NCS)(2)] complex on mesoporous anatase films were investigated to clarify the role of the carboxylate groups in the anchoring process of the dyes on the semiconductor surface. For this purpose UV-vis, Raman, resonance Raman, and ATR-FTIR spectroscopies have been used. The results of the Raman experiments at different excitation wavelengths demonstrate that photoinduced charge-transfer processes take place efficiently between the adsorbate and the substrate. Moreover, this is the first time that the Raman spectrum of a Ru-bpy dye (in this case, the dye N719) adsorbed on TiO(2) has been obtained without the resonance condition, only by means of SERS enhancement. The coordination of both complexes on the TiO(2) paste films is proposed to occur via bidentate or bridging linkage.

Internet-based cognitive testing in multiple sclerosis

Cognitive impairment in multiple sclerosis is difficult to study because of the heterogeneity and variability of this disease. The gold standard for measurement of cognitive function in multiple sclerosis is a full battery of neurocognitive tests, which is time consuming and expensive. Some cognitive tests like the PASAT, a measure of working verbal memory and processing speed, have been proposed for screening and follow-up of cognitive function in clinical trials. We studied whether we could measure cognitive function in multiple sclerosis over the Internet. For this we used the Cognitive Stability Index (CSI)™, developed for persons with known or suspected primary central nervous system illness. The CSI was compared with formal neurocognitive testing (NPsych) and the PASAT in a cross-sectional study of 40 consecutive multiple sclerosis patients with subjective cognitive complaints. NPsych revealed that only 18 of the 40 patients (46%) were cognitively impaired. Although both the CSI and the PASAT were equalivalent in their specificity (86%), the CSI was significantly more sensitive than the PASAT (83% versus 28%). We conclude that the CSI, because of its availability over the Internet, has great potential as a tool for screening and follow up of cognitive function in multiple sclerosis. Multiple Sclerosis 2007; 13: 1011—1019. http://msj.sagepub.com

Influence of the solvent on the surface-enhanced raman spectra of ruthenium(II) bipyridyl complexes

In the present work a new dye, [Ru(dcbpyH2)2(bpy-TPA2)](PF6)2, and the well-known (Bu4N)2[Ru(dcbpyH)2(NCS)2] complex were investigated. The electronic transitions of both dyes showed solvatochromic shifts due to specific interactions of the ligands with the solvent molecules. The surface-enhanced Raman (SER) spectra of the dyes dissolved in water, ethanol, and acetonitrile were measured in silver and gold colloidal solutions. The results demonstrate that the dyes were adsorbed on the metallic nanoparticles in different ways for different solvents. It was also found that in the gold colloid, the aqueous solutions of both dyes did not produce any SERS signal, whereas in ethanolic solution the SERS effect was very weak. Deprotonation, H-bonding, and donor-acceptor interactions seem to determine these different behaviors. Our results indicate the important role of the charge-transfer mechanism in SERS.

Effect of smoking on imatinib pharmacokinetics

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Background: Smoking is a potent inducer of the cytochrome P450 1A2 isoenzyme (CYP1A2) and may therefore effect the pharmacokinetics (PK) of drugs metabolized by CYP1A2. Indeed, clinical studies with erlotinib (metabolized by CYP3A4 and also partly by CYP1A2) have shown a major increase in erlotinib clearance in smokers versus non-smokers. The effect of smoking on the PK of imatinib, which is also metabolized by CYP3A4 and partly by CYP1A2, is unknown. We aimed to study the effect of smoking on imatinib PK in order to explain a part of the interpatient variation. Methods: The effect of smoking on the PK parameters was analyzed in 34 patients with gastro-intestinal stromal tumors or soft tissue sarcoma included in the EORTC-STBSG phase I and phase II trials. This cohort included 9 smokers and 25 non-smokers. The daily smoking habits of the study patients were retrieved retrospectively from the patient’s record. PK parameters assessed with NONMEM, version V were clearance (Cl), distribution volume (V), elimination half life (T1/2) and the dose standardized area under the concentration curve (AUC). We considered a 40% reduction in imatinib exposure clinically relevant and this study is adequately powered to detect this difference. Results: The mean PK parameters in the smokers versus the non-smokers group ± SD were: Cl; 9.6 ± 5.5 L/h vs 9.2 ± 4.6 L/h, V; 216.5 ± 114.3 L vs 207.0 ± 116.9 L, T1/2; 16.1 ± 6.0 h vs 16.5 ± 6.0 h, AUC; 133.6 ± 71.0 ng.h/ml.mg vs 142.3 ± 84.0 ng.h/ml.mg. There was no significant difference in PK parameters observed between the smokers and the non- smokers. Conclusion: This retrospective study suggest that the PK of imatinib was not affected by smoking and therefore does not explain the large variation in imatinib PK.

No significant financial relationships to disclose.

Comparison of defects in ProTaper hand-operated and engine-driven instruments after clinical use

AIM

To compare the type of defects and mode of material failure of engine-driven and hand-operated ProTaper instruments after clinical use.

METHODOLOGY

A total of 401 hand-operated and 325 engine-driven ProTaper instruments were discarded from an endodontic clinic over 17 months. Those that had fractured were examined for plastic deformation in lateral view and remounted for fractographical examination in scanning electron microscope. The mode of fracture was classified as 'fatigue' or 'shear' failure. The lengths of fractured segments in both instruments were recorded. Any distortion in hand instrument was noted. Data were analysed using chi-square, Fisher's exact or Student's t-test, where appropriate.

RESULTS

Approximately 14% of all discarded hand-operated instruments and 14% of engine-driven instruments were fractured. About 62% of hand instruments failed because of shear fracture, compared with approximately 66% of engine-driven instruments as a result of fatigue (P < 0.05). Approximately 16% of hand instruments were affected by shear, and either remained intact or was fractured, compared with 5% of engine-driven instruments (P < 0.05). The length of the broken fragment was significantly shorter in hand versus engine-driven group (P < 0.05). Approximately 7% of hand instruments were discarded intact but distorted (rarely for engine-driven instruments); all were in the form of unscrewing of the flutes. The location of defects in hand Finishing instruments was significantly closer to the tip than that for Shaping instruments (P < 0.05).

CONCLUSIONS

Under the conditions of this study (possibly high usage), the failure mode of ProTaper engine-driven and hand-operated instruments appeared to be different, with shear failure being more prevalent in the latter.

Therapeutic protein production in vivo after electroporation-assisted intramuscular gene delivery

Gene delivery to skeletal muscles assisted by electroporation(EP) is a promising strategy for in vivo production of the therapeutic proteins. But the commonly used procedure required the application of electric pulses with voltages at above 200V/cm and durations at least 40ms, which would result in several damages in the muscle and limited surviving cells expressing transgene. We reported here an optimization study of the various electric pulse parameters to reduce toxicity while maintain transgene expression. In addition, we also found that the secreted transgene product level detected in serum samples may not correlate with the total gene expression level in muscles. Based on our data, we'd propose some less damaging electroporation parameters that may be useful for intramuscular gene delivery and therapeutic protein production.

Keratinocyte growth factor/fibroblast growth factor-7-regulated cell migration and invasion through activation of NF-kappaB transcription factors

Keratinocyte growth factor (KGF)/fibroblast growth factor-7 (FGF-7) is a paracrine- and epithelium-specific growth factor produced by cells of mesenchymal origin. It acts exclusively through FGF-7 receptor (FGFR2/IIIb), which is expressed predominantly by epithelial cells, but not by fibroblasts, suggesting that it might function as a paracrine mediator of mesenchymal-epithelial interactions. KGF/FGF-7 plays an essential role in the growth of epithelial cells and is frequently overexpressed in cancers of epithelial origin such as pancreatic cancer, switching paracrine stimulation of KGF/FGF-7 to an autocrine loop. Less is known, however, about the signaling pathways by which KGF/FGF-7 regulates the response of epithelial cells. To delineate the signaling pathways activated by KGF/FGF-7 and examine cellular response to KGF/FGF-7 stimulation, we performed functional analysis of KGF/FGF-7 action. In this report, we show that KGF/FGF-7 activated nuclear factor kappaB (NF-kappaB), which in turn induced expression of VEGF, MMP-9, and urokinase-type plasminogen activator and increased migration and invasion of KGF/FGF-7-stimulated human pancreatic ductal epithelial cells. Expression of phosphorylation-defective IkappaBalpha (IkappaBalphaS32A,S36A), which blocked NF-kappaB activation, inhibited KGF/FGF-7-induced gene expression and cell migration and invasion. Our results demonstrate for the first time that KGF/FGF-7 induces NF-kappaB activation and that NF-kappaB plays an essential role in regulation of KGF/FGF-7-inducible gene expression and KGF/FGF-7-initiated cellular responses. Thus, these findings identify one signaling pathway for KGF/FGF-7-regulated cell migration and invasion and suggest that paracrine sources of KGF/FGF-7 are one of the malignancy-contributing factors from tumor stroma.

Mechanisms of synthetic serine protease inhibitor (FUT-175)-mediated cell death

BACKGROUND

Constitutive activation of nuclear factor-kappaB (NF-kappaB) is a frequent molecular alteration in pancreatic cancer and a number of studies have suggested that constitutive NF-kappaB activity plays a key role in the aggressive behavior of this disease. In an attempt to identify an effective therapeutic agent for pancreatic cancer, the authors studied the role of FUT-175, a synthetic serine protease inhibitor, in the inhibition of NF-kappaB activation and the induction of apoptotic responses.

METHODS

To examine the effect of FUT-175 on the inhibition of NF-kappaB and the induction of apoptosis in pancreatic cancer cell lines, Western and Northern blot analyses, electromobility shift (EMSA), luciferase reporter gene, DNA fragmentation, immunoprecipitation, in vitro kinase, small interfering RNA (siRNA), and chromatin immunoprecipitation (ChIP) assays were performed.

RESULTS

In a time-dependent and dose-dependent manner, FUT-175 inhibited IkappaBalpha phosphorylation and NF-kappaB activation, thereby inhibiting the antiapoptotic activity of NF-kappaB. Simultaneously, FUT-175 up-regulated the expression of tumor necrosis factor receptor-1 (TNFR1), which in turn activated the proapoptotic caspase-8 and Bid pathways and induced apoptosis in pancreatic cancer cells. FUT-175-induced activation of Fas-associated death domain (FADD) and caspase-8 was suppressed by RNA interference-mediated inhibition of TNFR1 expression. Furthermore, expression of the transcription factor PEA3 was up-regulated by FUT-175 and was involved in FUT-175-mediated TNFR1 expression.

CONCLUSIONS

These results suggested a possible mechanism by which FUT-175 may disrupt interconnected signaling pathways by both suppressing the NF-kappaB antiapoptotic activity and inducing TNFR-mediated apoptosis. Supported by this unique function as a NF-kappaB inhibitor and apoptosis inducer, this well-established synthetic serine protease inhibitor with as-of-yet poorly understood mechanisms of actions appears to be a potentially therapeutic agent for pancreatic cancer.

Impact of Lotensin and Salviae on the changes of TGF-beta1 and its receptors in a rat model of chronic cyclosporine-induced nephropathy

OBJECTIVES

Transforming growth factor-beta(1) (TGF-beta(1)) and its receptors, type 1 (TR-1) and type 2 (TR-2) play important roles in chronic cyclosporine (CsA)-induced nephropathy. Lotensin is known as an angiotensin-converting enzyme inhibitor and may reduce chronic CsA-induced nephropathy. Recently it is reported that Salviae (a Chinese medicine), which can improve microcirculation and decrease the expression of TGF-beta(1) has the same effect as that of lotensin. Therefore, in this study we assessed the effects of Lotensin or Salviae on the chronic CsA-induced upregulation of TGF-beta(1), TR-1, and TR-2 in a rat model.

MATERIALS AND METHODS

Sodium-depleted rats were administered CsA by gastric gavage and a new rat model of chronic CsA-induced nephropathy was established. Rats with chronic CsA-induced nephropathy were treated by lotensin or Salviae. The proteins of TGF-beta(1), TR-1, and TR-2, and the mRNA of TR-1 and TR-2 in the kidneys of CsA-treated rats, were measured by immunohistochemistry (IHC) and in situ hybridization (ISH). The results were investigated semiquantitatively by image analysis.

RESULTS

Lotensin or Salviae individually attenuated CsA-induced nephropathy in the rat models, and downregulated the protein expressions of TGF-beta(1), TR-1, and TR-2, and the mRNA transcripts of TR-1 and TR-2 in the rat model.

CONCLUSION

Our studies show that treatment with lotensin or Salviae is useful in preventing chronic CsA-induced nephropothy.

Potential role of estrogen receptor alpha (ERalpha) phosphorylated at Serine118 in human breast cancer in vivo

Post-translational modifications of proteins are known to be important in protein activity and ERalpha is known to be phosphorylated at multiple sites within the protein. The exact function of site-specific phosphorylation in ERalpha is unknown, although several hypotheses have been developed using site-directed mutagenesis and cell culture models. Targeting the ERalpha at the level of such post-translational modification pathways would be a new and exciting approach to endocrine therapy in breast cancer, but adequate knowledge is lacking with regard to the relevance of site-specific phosphorylation in ERalpha in human breast cancer in vivo. Recently, antibodies to P-Serine(118)-ERalpha and P-Serine(167)-ERalpha, two major sites of phosphorylation in ERalpha, have become available and some in vivo data are now available to complement studies in cells in culture. However, the in vivo data are somewhat contradictory and limited by the small cohorts used and the lack of standard well-characterized reagents and protocols.

Protective efficacy of a targeted anti-caries DNA plasmid against cariogenic bacteria infections

We have previously reported that a targeted anti-caries DNA plasmid pGJA-P/VAX which was constructed against the antigenic determinants of Streptococcus mutans (S. mutans) successfully induced antibody responses in mice and monkeys. The present study explored the protective efficacy of pGJA-P/VAX against cariogenic bacterial challenge. Groups of rats were orally challenged with S. mutans or Streptococcus sobrinus (S. sobrinus) and then immunized with pGJA-P/VAX or the vector pVAX1 intranasally. Serum IgG and salivary IgA antibody levels were assessed by an enzyme-linked immunosorbent assay and caries activity was evaluated by the Keyes method. The results showed that specific salivary IgA antibody responses were induced following intranasal vaccination with pGJA-P/VAX. Moreover, immunization with pGJA-P/VAX resulted in significantly reduced enamel and dentinal caries lesions in rats after S. mutans infection and significantly reduced enamel caries lesions after S. sobrinus infection. Thus, pGJA-P/VAX was not only protective toward S. mutans infection, but also provided cross-strain protection against S. sobrinus infection in rats.

The possible study of HuaXi-1 solution for all intra-abdominal organ preservation: a study in rats

OBJECTIVE

University of Wisconsin (UW) solution continues to be the most commonly used solution for intra-abdominal organs. However, it is expensive. Therefore, we have formulated HuaXi-1 (HX-1) solution. The aim of this research was to assess the effect of HX-1 solution compared to UW, Collins 2, and hypertonic citrate solutions on intra-abdominal organs.

METHODS

The effects of HX-1 solution for all intra-abdominal organ preservation were studied in a noncirculated, isolated, perfused rat liver model, in rat pancreas isografts in diabetic rats, and in a kidney autotransplant model. The effects were investigated by measuring hepatic tissue water content, sinusoidal lining cell mortality, Krebs-Henseleits perfusate, aspartate aminotransferase, the number of livers secreting bile during isolated perfusion, blood glucose, glucose tolerance tests, serum insulin of the rat pancreas-transplant recipients, the maximum serum creatinine levels, kidney graft survival rates, and observing the morphological changes in liver, pancreas, and kidneys.

RESULTS

HX-1 solution preserved rat liver well for 24 hours as effectively as UW, rat pancreas as well for 48 hours, and dog kidney as well for 72 hours.

CONCLUSION

The experimental findings indicated that HX-1 solution was effective to preserve all intra-abdominal organs; it may simplify cold storage of organs for transplantation.

Regulation of nuclear translocation of HDAC3 by IkappaBalpha is required for tumor necrosis factor inhibition of peroxisome proliferator-activated receptor gamma function

Inhibition of peroxisome proliferator-activated receptor gamma (PPARgamma) function by TNF-alpha contributes to glucose and fatty acid metabolic disorders in inflammation and cancer, although the molecular mechanism is not fully understood. In this study, we demonstrate that nuclear translocation of HDAC3 is regulated by TNF-alpha, and this event is required for inhibition of transcriptional activity of PPARgamma by TNF-alpha. HDAC3 is associated with IkappaBalpha in the cytoplasm. After IkappaBalpha degradation in response to TNF-alpha, HDAC3 is subject to nuclear translocation, leading to an increase in HDAC3 activity in the nucleus. This event leads to subcellular redistribution of HDAC3. Knock-out of IkappaBalpha, but not p65 or p50, leads to disappearance of HDAC3 in the cytoplasm, which is associated with HDAC3 enrichment in the nucleus. These data suggest that inhibition of PPARgamma by TNF-alpha is not associated with a reduction in the DNA binding activity of PPARgamma. Rather, these results suggest that IkappaBalpha-dependent nuclear translocation of HDAC3 is responsible for PPARgamma inhibition by TNF-alpha.

The aggressive form of cherubism: report of two cases in unrelated families

Cherubism is a benign lesion that causes painless symmetrical enlargement of the jaws, usually with a familial tendency. We describe in two Chinese families two cases of the aggressive form of cherubism with extensive swelling on both sides of the mandible, typical microscopic findings, and apparent familial history.

Defects in ProTaper S1 instruments after clinical use: fractographic examination

AIM

To investigate the mode of failure of a brand of nickel-titanium instruments separated during clinical use, by detailed examination of the fracture surface.

METHODOLOGY

A total of 122 ProTaper S1 instruments were discarded from an endodontic clinic at a stomatological school in China over a period of 17 months; 28 had fractured. These fractured instruments were ultrasonically cleaned, autoclaved and then examined under a scanning electron microscope. From the lateral view the fracture was classified into 'torsional' or 'flexural'. The specimens were then re-mounted and the presence of characteristics of shear failure and fatigue striations was recorded under high-power view of the fracture surface. The difference in the mean lengths of fractured segment between the shear and fatigue groups was compared using Student's t-test.

RESULTS

Twenty-seven separated instruments were available for analysis. Under low-power magnification, only two fell into the category of 'torsional' failure when examined laterally; the others appeared to be 'flexural'. Close examination of the fracture surface revealed the presence of fatigue striations in 18 specimens. Nine instruments (including the two putative 'torsional' failures above) fell into the shear fracture group, in which fatigue striations were absent or characteristics of shear failure of the material were found. The mean length of fractured segments resulting from fatigue failure (4.3+/-1.9 mm) was significantly greater than that for shear failure (2.5+/-0.8 mm) (P<0.001, two-sample t-test).

CONCLUSIONS

Examination of the fracture surface at high magnification is essential to reveal features that may indicate the possible origin of cracks and the mode of material failure. Macroscopic or lateral examination of separated instruments would fail to reveal the true mechanism of failure. Fatigue seems to be an important reason for the separation of rotary instruments during clinical use.

Population pharmacokinetics of imatinib mesylate in patients with chronic-phase chronic myeloid leukaemia: results of a phase III study

AIMS

This study was designed to investigate the biochemical and physiological covariates or comedications that affect the pharmacokinetics of imatinib mesylate in patients with chronic-phase chronic myeloid leukaemia (CP CML).

METHODS

Pharmacokinetic data were analyzed in 371 patients receiving 400 mg imatinib once daily during a phase III trial of imatinib vs interferon-alfa plus cytarabine for the treatment of newly diagnosed CP CML. Covariates included age, weight, sex, ethnicity, haemoglobin (Hb) concentration, white blood cell (WBC) count, liver function, and creatinine concentration. Blood samples for imatinib analysis were taken on treatment days 1 and 29. Nonlinear mixed effects modelling was used for the population pharmacokinetic analysis.

RESULTS

Population mean estimates (95% confidence interval) at day 1 for apparent clearance (CL) and apparent volume of distribution (V) of imatinib were 14 (13-15) l h(-1) and 252 (237-267) l, respectively. Modelling suggested that CL decreased by 4 (3-5) l h(-1) from day 1 to day 29, whereas V remained unchanged. Interindividual variability in CL and V was 32% and 31%, respectively. Weight, Hb, and WBC count demonstrated small effects on CL and V. Doubling body weight or Hb or halving the WBC count was associated with a 12%, 86% and 8% increase in CL, respectively, and a 32%, 60% and 5% increase in V, respectively. Comedications showed no clear effects on imatinib CL.

CONCLUSIONS

Population covariates and coadministered drugs minimally affected imatinib pharmacokinetics in newly diagnosed CP CML patients.

Defects in ProTaper S1 instruments after clinical use: longitudinal examination

AIM

To evaluate defects in ProTaper shaping instrument S1 after a defined schedule of clinical use.

METHODOLOGY

Among all ProTaper files discarded from an endodontic clinic at a stomatological school in China over a period of 17 months, 122 S1 instruments were collected. They were ultrasonically cleaned, autoclaved and then examined in the laboratory. Any instrument separation was noted; the average length involved was determined. The 0.5 mm region on either side of this length of discarded but intact instruments was examined circumferentially by scanning electron microscope. The region adjacent to the broken end of the fractured instruments was also examined in the same way.

RESULTS

One specimen was lost during processing. Of the remaining 121 instruments, 27 were separated with a mean fracture length of 3.67 mm from the tip. Of these, two files showed macroscopically torsional fracture and the others showed signs of flexural fatigue. Only one file that had not fractured showed visible unwinding defects. Examination of the 3.1-4.1 mm region of other unfractured instruments revealed the presence of microcracks, surface debris, pitting and/or wear of their cutting edges. Some debris particles seemed to have been trapped in crack-like structures.

CONCLUSIONS

Multiple use of ProTaper S1 pre-disposed the instrument to microcrack formation and wear of the cutting edges. There was a low prevalence of plastic deformation and most ProTaper S1 instruments failed without discernible sign of unwinding of the flutes. Further studies should address the mode of failure and the role of debris particles in the fracture mechanism.

A novel locus for autosomal dominant hereditary gingival fibromatosis, GINGF3, maps to chromosome 2p22.3-p23.3

Hereditary gingival fibromatosis (HGF) is a rare, benign disorder characterized by slowly progressive fibrous overgrowth of the gingiva. To date, two loci have been mapped in familial cases with autosomal dominant non-syndromic HGF: GINGF (MIM 135300) on chromosome 2p21-p22 and GINGF2 (MIM 605544) on chromosome 5q13-q22. Of the two loci, only SOS1 (son of sevenless one, MIM 182530) gene underlying GINGF locus has been identified. Ascertainment of a large Chinese family has allowed the mapping of a novel locus to 2p22.3-p23.3, GINGF3. Haplotype construction and analysis localized the new locus to an 11.4-cM interval between markers D2S2221 (telomeric) and D2S1788 (centromeric). The maximum two-point limit of detection (LOD) score of 3.45 (theta=0) and multipoint LOD score of 5.00 for marker D2S390 strongly supported linkage to this region. Thus, this genetic interval is distal to and does not overlap with the previously described locus, GINGF, on 2p21-p22.

Inducible upregulation of oestrogen receptor-beta1 affects oestrogen and tamoxifen responsiveness in MCF7 human breast cancer cells

To investigate the effect of altered oestrogen receptor (ER)alpha and ERbeta expression on oestrogen and anti-oestrogen action in breast cancer, we have stably expressed an inducible ERbeta1 in MCF7 breast cancer cells. Stably expressing clones were isolated and over-expression of ERbeta1 correlated with increased levels of specific radiolabelled oestradiol (E2) binding. Increased ERbeta1 did not affect endogenous levels of ERalpha but increased progesterone receptor (PR) levels. Over-expression of ERbeta1 reduced growth responses to E2 in contrast to little if any effect of over-expression of ERalpha. In oestrogen-replete conditions, over-expression of ERbeta1 but not ERalpha reduced proliferation. Over-expression of ERbeta1 did not result in anti-oestrogen resistance but was associated with increased sensitivity to 4-hydroxytamoxifen. Our results suggested that over-expression of ERbeta1 in the presence of an endogenously expressed ERalpha was associated with tamoxifen sensitivity but may negatively modulate ERalpha-mediated growth. However, not all ERalpha activities were inhibited since endogenous PR expression was increased by both ERalpha and ERbeta1 over-expression. These data paralleled those seen in some in vivo studies showing a relationship between PR and ERbeta expression as well as ERbeta expression and tamoxifen sensitivity of ER-positive breast cancer patients. These models are relevant and will be useful for dissecting the role of ERbeta1 expression in ER-positive breast cancer.

Function of polo-like kinase 3 in NF-kappaB-mediated proapoptotic response

RelA, the p65 subunit of NF-kappaB transcription factors, plays a key role in regulation of antiapoptotic and proapoptotic responses. However, the downstream target genes regulated by RelA-NF-kappaB in the initiation of proapoptotic signaling were not identified. We previously showed that RelA-NF-kappaB functioned as a proapoptotic factor by activating the p53-signaling pathway in response to doxycycline-induced superoxide. In the present study, we demonstrate that the ability of doxycycline/superoxide to induce expression of polo-like kinase 3 (Plk3) depends on NF-kappaB activity. We identified a kappaB binding site in the promoter of Plk3, and this kappaB site is directly involved in its induction by the RelA-NF-kappaB complex. Plk3 formed a complex with p53 and was involved in the phosphorylation of p53 on Ser-20 in response to superoxide. Inhibition of Plk3 expression by Plk3 small interfering RNA suppressed the doxycycline/superoxide-mediated apoptosis. Overexpression of wild-type Plk3 in HCT116 p53+/+ cells induced rapid apoptosis, whereas overexpression of wild-type Plk3 in HCT116 p53-/- cells and the kinase-defective mutant Plk3(K91R) in p53+/+ cells induced delayed onset of apoptosis. Furthermore, mutagenesis of Plk3 showed that the N-terminal domain (amino acids 1-26) is essential for the induction of delay onset of apoptosis. These data show that Plk3 is a RelA-NF-kappaB-regulated gene that induces apoptosis in both p53-dependent and -independent signaling pathways, suggesting a possible mechanism for RelA-NF-kappaB-regulated proapoptotic responses.

The pathogenesis of discogenic low back pain

Discogenic low back pain is a common cause of disability, but its pathogenesis is poorly understood. We collected 19 specimens of lumbar intervertebral discs from 17 patients with discogenic low back pain during posterior lumbar interbody fusion, 12 from physiologically ageing discs and ten from normal control discs. We investigated the histological features and assessed the immunoreactive activity of neurofilament (NF200) and neuropeptides such as substance P (SP) and vasoactive-intestinal peptide (VIP) in the nerve fibres.

The distinct histological characteristic of the painful disc was the formation of a zone of vascularised granulation tissue from the nucleus pulposus to the outer part of the annulus fibrosus along the edges of the fissures. SP-, NF- and VIP-immunoreactive nerve fibres in the painful discs were more extensive than in the control discs. Growth of nerves deep into the annulus fibrosus and nucleus pulposus was observed mainly along the zone of granulation tissue in the painful discs. This suggests that the zone of granulation tissue with extensive innervation along the tears in the posterior part of the painful disc may be responsible for causing the pain of discography and of discogenic low back pain.

NF-kappaB and AP-1 connection: mechanism of NF-kappaB-dependent regulation of AP-1 activity

Nuclear factor kappaB (NF-kappaB) and activator protein 1 (AP-1) transcription factors regulate many important biological and pathological processes. Activation of NF-kappaB is regulated by the inducible phosphorylation of NF-kappaB inhibitor IkappaB by IkappaB kinase. In contrast, Fos, a key component of AP-1, is primarily transcriptionally regulated by serum responsive factors (SRFs) and ternary complex factors (TCFs). Despite these different regulatory mechanisms, there is an intriguing possibility that NF-kappaB and AP-1 may modulate each other, thus expanding the scope of these two rapidly inducible transcription factors. To determine whether NF-kappaB activity is involved in the regulation of fos expression in response to various stimuli, we analyzed activity of AP-1 and expression of fos, fosB, fra-1, fra-2, jun, junB, and junD, as well as AP-1 downstream target gene VEGF, using MDAPanc-28 and MDAPanc-28/IkappaBalphaM pancreatic tumor cells and wild-type, IKK1-/-, and IKK2-/- murine embryonic fibroblast cells. Our results show that elk-1, a member of TCFs, is one of the NF-kappaB downstream target genes. Inhibition of NF-kappaB activity greatly decreased expression of elk-1. Consequently, the reduced level of activated Elk-1 protein by extracellular signal-regulated kinase impeded constitutive, serum-, and superoxide-inducible c-fos expression. Thus, our study revealed a distinct and essential role of NF-kappaB in participating in the regulation of elk-1, c-fos, and VEGF expression.

Overexpression of synuclein-gamma in pancreatic adenocarcinoma

BACKGROUND

Currently, pancreatic adenocarcinoma is the fourth leading cause of cancer-related death in the United States. Despite the advances in pancreatic carcinoma research, patients with this devastating disease have a very poor prognosis. To identify the gene expression profile of pancreatic carcinoma, an important step in the process of developing new diagnostic and therapeutic strategies, the authors investigated the alteration of gene expression in this disease.

METHODS

The authors analyzed a public serial analysis of gene expression (SAGE) database and examined in greater detail the expression of synuclein-gamma mRNA in several pancreatic carcinoma cell lines and tumor tissue samples by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis and Northern blot analysis. The expression of synuclein-gamma protein was investigated further by immunohistochemical and Western blot analyses using tumor cell lines, tumor tissue, and serum samples.

RESULTS

Synuclein-gamma mRNA was overexpressed in 11 of 12 pancreatic carcinoma cell lines, including AsPc-1, MDAPanc28, Capan-1, Capan-2, PANC-1, HS766T, MDAPanc3, MDAPanc48, Colo357FG, MiaPaCa2, CFPac1, and BxPc3. The expression of synuclein-gamma protein was detectable in 8 of 12 pancreatic carcinoma cell lines (67%) and in 22 of 32 pancreatic tumor tissue samples (69%) by Western blot analysis. On immunohistochemical staining, synuclein-gamma protein was present in 61% of the tumor tissue samples examined from patients with Stage I and II pancreatic carcinoma. The overexpression of synuclein-gamma is correlated with perineural and lymph node invasion. Synuclein-gamma protein also was detectable by Western blot in serum samples from 21 of 56 patients (38%) with pancreatic carcinoma.

CONCLUSIONS

Synuclein-gamma, which initially was described as a breast carcinoma-specific gene involved in invasion, metastasis, and chemotherapy resistance, was frequently overexpressed in pancreatic carcinoma. Overexpression of synuclein-gamma may play a role in pancreatic carcinoma invasion. Further studies will be necessary to determine the role of synuclein-gamma in pancreatic carcinoma.