Accessibility of a critical prion protein region involved in strain recognition and its implications for the early detection of prions

Human prion diseases are characterized by the accumulation in the brain of proteinase K (PK)-resistant prion protein designated PrP27-30 detectable by the 3F4 antibody against human PrP109-112. We recently identified a new PK-resistant PrP species, designated PrP^*20, in uninfected human and animal brains. It was preferentially detected with the 1E4 antibody against human PrP 97-108 but not with the anti-PrP 3F4 antibody, although the 3F4 epitope is adjacent to the 1E4 epitope in the PrP^*20 molecule. The present study reveals that removal of the N-terminal amino acids up to residue 91 significantly increases accessibility of the 1E4 antibody to PrP of brains and cultured cells. In contrast to cells expressing wild-type PrP, cells expressing pathogenic mutant PrP accumulate not only PrP^*20 but also a small amount of 3F4-detected PK-resistant PrP27-30. Remarkably, during the course of human prion disease, a transition from an increase in 1E4-detected PrP^*20 to the occurrence of the 3F4-detected PrP27-30 was observed. Our study suggests that an increase in the level of PrP^*20 characterizes the early stages of prion diseases.

Identification of a novel HLA-B*54 allele, B*5411, by sequence-based typing in a Chinese individual

We report here a novel human leukocyte antigen (HLA)-B*5411 allele identified by sequence-based typing in a Chinese individual. The novel B*5411 is identical to B*5404, with the exception of four base substitutions at position 120 (A>C), 134 (G>C), 143 (C>G), and 156 (A>T) of exon 3 resulting in codon no. 131, changed from AGC (Ser) to CGC (Arg), and codon no. 143, changed from ACC (Thr) to TCC (Ser).

Cisplatin nephrotoxicity: mechanisms and renoprotective strategies

Cisplatin is one of the most widely used and most potent chemotherapy drugs. However, side effects in normal tissues and organs, notably nephrotoxicity in the kidneys, limit the use of cisplatin and related platinum-based therapeutics. Recent research has shed significant new lights on the mechanism of cisplatin nephrotoxicity, especially on the signaling pathways leading to tubular cell death and inflammation. Renoprotective approaches are being discovered, but the protective effects are mostly partial, suggesting the need for combinatorial strategies. Importantly, it is unclear whether these approaches would limit the anticancer effects of cisplatin in tumors. Examination of tumor-bearing animals and identification of novel renoprotective strategies that do not diminish the anticancer efficacy of cisplatin are essential to the development of clinically applicable interventions.

Tumor necrosis factor-alpha in cisplatin nephrotoxicity: a homebred foe?

A robust inflammatory response involving tumor necrosis factor-alpha (TNF-alpha) is induced during cisplatin nephrotoxicity. Using chimeric models, Reeves and colleagues now demonstrate that resident kidney cells, rather than infiltrating immune cells, are the major producers of TNF-alpha. Blockade of TNF-alpha attenuates inflammation and associated kidney injury.

Protein kinase C alpha-CARMA3 signaling axis links Ras to NF-kappa B for lysophosphatidic acid-induced urokinase plasminogen activator expression in ovarian cancer cells

We reported previously that a signaling pathway consisting of G(i)-Ras-NF-kappaB mediates lysophosphatidic acid (LPA)-induced urokinase plasminogen activator (uPA) upregulation in ovarian cancer cells. However, it is not clear what signaling components link Ras to nuclear factor (NF)-kappaB for this LPA-induced event. In the present study, we found that treatment of protein kinase C (PKC) inhibitors including conventional PKC (cPKC) inhibitor Gö6976 abolished LPA-induced uPA upregulation in ovarian cancer cell lines tested, indicating the importance of cPKC activity in this LPA-induced event. Indeed, LPA stimulation led to the activation of PKCalpha and Ras-PKCalpha interaction. Although constitutively active mutants of PKCalpha (a cPKC), PKCtheta (a novel PKC (nPKC)) and PKCzeta (an atypical PKC (aPKC)) were all able to activate NF-kappaB and upregulate uPA expression, only dominant-negative PKCalpha mutant attenuated LPA-induced NF-kappaB activation and uPA upregulation. These results suggest that PKCalpha, rather than PKC isoforms in other PKC classes, participates in LPA-induced NF-kappaB activation and uPA upregulation in ovarian cancer cells. To determine the signaling components downstream of PKCalpha mediating LPA-induced uPA upregulation, we showed that forced expression of dominant-negative CARMA3 or silencing CARMA3, Bcl10 and MALT1 with specific siRNAs diminished these LPA-induced events. Furthermore, we demonstrated that PKCalpha/CARMA3 signaling axis is important in LPA-induced ovarian cancer cell in vitro invasion.

HLA-B*9518 allele identified in the Chinese population

We report here a novel HLA-B*9518 allele by sequence-based typing in the Chinese population. The new B*9518 is identical to B*150101 with an exception of one base substitution at position 19 of exon 3 where a 'G' change to 'T' resulting in codon 97 changed from AGG (Arg) to ATG (Met).

Unidirectional crosstalk between Bcl-xL and Bcl-2 enhances the angiogenic phenotype of endothelial cells

Expression of Bcl-x(L) correlates with the clinical outcomes of patients with cancer. While the role of Bcl-2 in angiogenesis is becoming increasingly evident, the function of Bcl-x(L) in angiogenesis is unclear. Here, we showed that epidermal growth factor (EGF) induces in vitro capillary sprouting and Bcl-x(L) expression in primary endothelial cells. Bcl-x(L)-transduced human dermal microvascular endothelial cells (HDMEC-Bcl-x(L)), but not empty vector control cells, spontaneously organize into capillary-like sprouts. Searching for a mechanism to explain these responses, we observed that Bcl-x(L) induced expression of the pro-angiogenic chemokines CXC ligand-1 (CXCL1) and CXC ligand-8 (CXCL8), and that blockade of CXC receptor-2 (CXCR2) signaling inhibited spontaneous sprouting of HDMEC-Bcl-x(L). Bcl-x(L) led to Bcl-2 upregulation, but Bcl-2 did not upregulate Bcl-x(L), suggesting the existence of a unidirectional crosstalk from Bcl-x(L) to Bcl-2. EGF and Bcl-x(L) activate the mitogen-activated protein kinase/ERK pathway resulting in upregulation of vascular endothelial growth factor (VEGF), a known inducer of Bcl-2 in endothelial cells. Inhibition of VEGF receptor signaling in HDMEC-Bcl-x(L) prevented Bcl-2 upregulation and demonstrated the function of a VEGF-mediated autocrine loop. Bcl-2 downregulation by RNAi blocked CXCL1 and CXCL8 expression downstream of Bcl-x(L), and markedly decreased angiogenesis in vivo. We conclude that Bcl-x(L) functions as a pro-angiogenic signaling molecule controlling Bcl-2 and VEGF expression. These results emphasize a complex interplay between Bcl-2 family members beyond their classical roles in apoptosis.

The pathological role of Bax in cisplatin nephrotoxicity

Nephrotoxicity induced by cisplatin involves tubular cell necrosis and apoptosis; the latter of which may be initiated by multiple mechanisms including activation of the intrinsic mitochondrial pathway. In cultured tubular epithelial cells, cisplatin can activate the proapoptotic protein Bax resulting in cytochrome c release, caspase activation, and apoptosis. Definitive evidence for the involvement of Bax in cisplatin nephrotoxicity in vivo, however, is lacking. We analyzed Bax regulation during cisplatin nephrotoxicity in wild-type mice and determined the pathological role of Bax using mice in which this gene was knocked out. In wild-type mice, cisplatin induced Bax in renal tubular cells which became active, accumulated in the mitochondria, and was accompanied by acute kidney injury. Compared with the wild-type mice renal function, as measured by blood urea nitrogen and serum creatinine, was partially but significantly preserved in Bax knockout mice. The number of apoptotic cells was decreased as was general tissue damage. Additionally, cisplatin-induced cytochrome c release was attenuated in the Bax-deficient mice. This significant decrease in apoptosis and in cytochrome c release was also mirrored in primary cultures of proximal tubular cells prepared from Bax knockout animals. Collectively, our results provide compelling evidence for a role of Bax and its related apoptotic pathway in cisplatin nephrotoxicity.

Opiate withdrawal modifies synaptic plasticity in subicular-nucleus accumbens pathway in vivo

Subiculum receives output of hippocampal CA1 neurons and projects glutamatergic synapses onto nucleus accumbens (NAc), the subicular-NAc pathway linking memory and reward system. It is unknown whether morphine withdrawal influences synaptic plasticity in the subicular-NAc pathway. Here, we recorded the field excitatory postsynaptic potential (EPSP) within the shell of NAc by stimulating ventral subiculum in anesthetized adult rats. We found that high frequency stimulation (HFS, 200 Hz) induced long-term potentiation (LTP) but low frequency stimulation (LFS, 1 Hz) failed to induce long-term depression (LTD) in control animals. However, behavioral stress enabled LFS to induce a reliable LTD (sLTD) that was dependent on the glucocorticoid receptors. Both LTP and sLTD were prevented by the N-methyl-d-aspartate receptor antagonist AP-5. After repeated morphine treatment for 12 days, acute withdrawal (12 h) impaired LTP but had no effect on sLTD; prolonged withdrawal (4 days) restored the LTP but impaired the sLTD. Remarkably, basal synaptic efficacy reflected by baseline EPSP amplitude was potentiated in acute withdrawal but was depressed in prolonged withdrawal. Thus, acute and prolonged opiate withdrawal may cause endogenous LTP and LTD in the subicular-NAc pathway that occludes the subsequent induction of synaptic plasticity, demonstrating adaptive changes of the NAc functions during opiate withdrawal.

Activation of iCaspase-9 in neovessels inhibits oral tumor progression

Tumors of the oral cavity are highly vascularized malignancies. Disruption of neovascular networks was shown to limit the access of nutrients and oxygen to tumor cells and inhibit tumor progression. Here, we evaluated the effect of the activation of an artificial death switch (iCaspase-9) expressed in neovascular endothelial cells on the progression of oral tumors. We used biodegradable scaffolds to co-implant human dermal microvascular endothelial cells stably expressing iCaspase-9 (HDMEC-iCasp9) with oral cancer cells expressing luciferase (OSCC3-luc or UM-SCC-17B-luc) in immunodeficient mice. Alternatively, untransduced HDMEC were co-implanted with oral cancer cells, and a transcriptionaly targeted adenovirus (Ad-VEGFR2-iCasp-9) was injected locally to deliver iCaspase-9 to neovascular endothelial cells. In vivo bioluminescence demonstrated that tumor progression was inhibited, and immunohistochemistry showed that microvessel density was decreased, when iCaspase-9 was activated in tumor-associated microvessels. We conclude that activation of iCaspase-9 in neovascular endothelial cells is sufficient to inhibit the progression of xenografted oral tumors.

The differential effects of low dose and high dose concanavalin A on cytokine profile and their importance in liver injury

OBJECTIVE

Intravenous injection of concanavalin A (Con A) can cause mice to suffer from acute liver failure in a dose dependent manner and little is known about the difference between the high dose and the low dose of Con A regarding the immune response they initiate. The aim of this study was to analyze whether differential effects exist between the low dose and high dose of concanavalin A on the intrahepatic immune system and their importance in the development of liver injury.

MATERIALS AND METHODS

A high dose of Con A (15 microg/g) was injected intravenously to induce murine hepatitis. A low dose of Con A (3 microg/g) was injected intravenously 12 h before the injection of the high dose of Con A (15 microg/g). Liver injury was evaluated by serum transaminase assay and H&E staining. Serum cytokine concentrations were determined by enzyme-linked immunosorbent assay (ELISA), intrahepatic cytokine and Fas mRNA levels by reverse transcriptase polymerase chain reaction. Intracellular cytokine expression and FasL expression were analyzed by flow cytometry and Fas protein expression in hepatocytes by Western-blotting. Intrahepatic apoptosis was evaluated by terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL).

RESULTS

Low dose Con A injection induced a distinct cytokine expression profile, characterized by a preferentially elevated serum IL-6 at the early stage of stimulation, whereas high dose Con A injection provoked significant elevation of various cytokines involved in Con A-induced hepatitis. Pretreatment with a low, nonhepatoxic dose of Con A (3 microg/g) significantly decreased production of proinflammatory cytokines induced by the high dose Con A (15 microg/g). Furthermore, low dose Con A pretreatment could significantly decrease the serum levels of transaminases and liver necrosis induced by high dose of Con A. The intrahepatic Fas expression was also apparently reduced, accompanied by a decrease in hepatocyte apoptosis.

CONCLUSION

Low dose Con A stimulation induced a different cytokine profile from high dose Con A stimulation resulting in differential importance in the development of liver injury.

Regulation of PUMA-alpha by p53 in cisplatin-induced renal cell apoptosis

Nephrotoxicity is a major side effect of cisplatin, a widely used cancer therapy drug. Depending on its concentration, cisplatin induces necrosis or apoptosis of tubular cells in the kidneys, whereas the underlying injury mechanism is unclear. Our recent work has suggested a critical role for p53 in cisplatin-induced tubular cell apoptosis; nevertheless, the apoptotic events triggered by p53 remain elusive. The current study has examined Bcl-2 family proteins, critical regulators of apoptosis that may be subjected to p53 regulation. Following cisplatin treatment, the expression of Bcl-xL, an antiapoptotic molecule, was suppressed, while the expression of Bak, a proapoptotic molecule, increased slightly. Of interest, PUMA-alpha, a newly identified p53-responsive proapoptotic Bcl-2 family protein, was drastically induced by cisplatin. PUMA-alpha induction preceded or paralleled the development of apoptosis. Induced PUMA-alpha was localized in mitochondria and appeared to antagonize Bcl-xL via molecular interaction. PUMA-alpha induction during cisplatin treatment was attenuated by pifithrin-alpha, a pharmacological inhibitor of p53, which was accompanied by the amelioration of Bax activation, cytochrome c release and apoptosis. Moreover, PUMA-alpha induction was suppressed by dominant-negative p53. Importantly, cisplatin-induced apoptosis was ameliorated in PUMA-alpha knockout cells. In vivo, cisplatin induced PUMA-alpha in the kidneys, and the inductive response was abrogated in p53-deficient animals. Together, this study has demonstrated the first compelling evidence for the involvement of PUMA-alpha in p53-mediated renal cell apoptosis during cisplatin nephrotoxicity.

Inducible nitric oxide synthase activity is essential for inhibition of prostatic tumor growth by interferon-beta gene therapy

We have previously reported that adenoviral vector-mediated interferon (IFN)-beta gene therapy inhibits orthotopic growth of human prostate cancer cells in nude mice. The purpose of this study was to determine efficacy and mechanisms of this therapy in immune-competent mice. TRAMP-C2Re3 mouse prostate cancer cells infected with 100 multiplicity of infection (MOI) of adenoviral vector encoding for mouse IFN-beta (AdmIFN-beta), but not AdE/1 (a control adenoviral vector), produced approximately 60 ng/10(5) cells/24 h of IFN-beta. The tumorigenicity of AdmIFN-beta-transduced cells was dramatically reduced in the prostates of C57BL/6 mice. A single intratumoral injection of 2 x 10(9) PFU (plaque-forming unit) of AdmIFN-beta inhibited tumor growth by 70% and prolonged survival of tumor-bearing mice. Intriguingly, this AdmIFN-beta therapy did not alter the growth of tumors in inducible nitric oxide synthase (iNOS)-null C57BL/6 mice. Immunohistochemical analysis revealed that treatment of tumors with AdmIFN-beta in wild-type C57BL/6 mice led to increased iNOS expression, decreased microvessel density, decreased cell proliferation, and increased apoptosis. Furthermore, quantitative reverse-transcriptional PCR analysis showed that AdmIFN-beta therapy, in C57BL/6 but not the iNOS-null counterparts, reduced levels of the mRNAs for angiopoietin, basic fibroblast growth factor, matrix metalloproteinase-9, transforming growth factor-beta1, vascular endothelial growth factor (VEGF)-A, and VEGF-B, as well as the antiapoptotic molecule endothelin-1. These data indicated that IFN-beta gene therapy could be effective alternative for the treatment of locally advanced prostate cancer and suggest an obligatory role of NO in IFN-beta antitumoral effects in vivo.

Antiangiogenic gene therapy: disruption of neovascular networks mediated by inducible caspase-9 delivered with a transcriptionally targeted adenoviral vector

The activation of an inducible caspase (iCaspase-9) mediates apoptosis of neovascular endothelial cells, and overcomes the prosurvival effect of vascular endothelial growth factor or basic fibroblast growth factor. The potential utilization of direct activation of caspases as an antiangiogenic strategy for treatment of angiogenesis-dependent diseases (eg cancer) requires expression of the inducible caspase primarily in the tumor endothelium. The objective of this work was to develop and characterize a transcriptionally targeted adenoviral vector that mediates expression of iCaspase-9 specifically in neovascular endothelial cells. We observed that adenoviral vectors containing the human VEGFR2 promoter induced reporter gene expression primarily in proliferating human dermal microvascular endothelial cells (HDMEC). HDMEC transduced with recombinant adenoviral vectors containing iCaspase-9 under regulation of the VEGFR2 promoter (Ad-hVEGFR2-iCaspase-9) and exposed to a cell-permeable dimerizer drug (AP20187), presented higher caspase-3 activity and apoptosis than controls (P < or = 0.05). Using the SCID Mouse Model of Human Angiogenesis, we observed that local delivery of Ad-hVEGFR2-iCaspase-9 followed by intraperitoneal injection of AP20187 resulted in endothelial cell apoptosis and local ablation of microvessels. We believe that this constitutes the first report of a transcriptionally targeted antiangiogenic adenoviral vector that mediates neovascular disruption upon activation of a caspase-based artificial death switch.

Does the valve regulated release of urine from the bladder decrease encrustation and blockage of indwelling catheters by crystalline proteus mirabilis biofilms?

PURPOSE

We tested whether valve regulated, intermittent flow of urine from catheterized bladders decreases catheter encrustation.

MATERIALS AND METHODS

Laboratory models of the catheterized bladder were infected with Proteus mirabilis. Urine was allowed to drain continuously through the catheters or regulated by valves to drain intermittently at predetermined intervals. The time that catheters required to become blocked was recorded and encrustation was visualized by scanning electron microscopy.

RESULTS

When a manual valve was used to drain urine from the bladder at 2-hour intervals 4 times during the day, catheters required significantly longer to become blocked than those on continuous drainage (mean 62.6 vs 35.9 hours, p = 0.039). A similar 1.7-fold increase occurred when urine was drained at 4-hour intervals 3 times daily. Experiments with an automatic valve in which urine was released at 2 or 4-hour intervals through the day and night also showed a significant increase in mean time to blockage compared with continuous drainage (p = 0.001). Scanning electron microscopy confirmed that crystalline biofilm was less extensive on valve regulated catheters.

CONCLUSIONS

Valve regulated, intermittent flow of urine through catheters increases the time that catheters require to become blocked with crystalline biofilm. The most beneficial effect was recorded when urine was released from the bladder at 4-hour intervals throughout the day and night by an automatic valve.

Targeting signal transduction pathways by chemopreventive agents

Cancer is a dynamic process that involves many complex factors, which may explain why a "magic bullet" cure for cancer has not been found. Death rates are still rising for many types of cancers, which possibly contributes to the increased interest in chemoprevention as an alternative approach to the control of cancer. This strategy for cancer control is based on the presumption that because cancer develops through a multi-step process, each step may be a prospective target for reversing or suppressing the process. Thus, the design and development of chemopreventive agents that act on specific and/or multiple molecular and cellular targets is gaining support as a rational approach to control cancer. Nutritional or dietary factors have attracted a great deal of interest because of their perceived ability to act as highly effective chemopreventive agents. They are professed as being generally safe and may have efficacy as chemopreventive agents by preventing or reversing premalignant lesions and/or reducing second primary tumor incidence. Many of these dietary compounds appear to act on multiple target signaling pathways. Some of the most interesting and well documented are resveratrol and components of tea, including EGCG, theaflavins and caffeine. This review will focus on recent work regarding three well-accepted cellular/molecular mechanisms that may at least partially explain the effectiveness of selected food factors, including those indicated above, as chemopreventive anti-promotion agents. These food compounds may act by: (1) inducing apoptosis in cancer cells; (2) inhibiting neoplastic transformation through the inhibition of AP-1 and/or NF-kappaB activation; and/or (3) suppressing COX-2 overexpression in cancer cells.

Identification of two contiguous minimally deleted regions on chromosome 1p36.31-p36.32 in oligodendroglial tumours

Loss of the short arm of chromosome 1 is a hallmark of oligodendroglial tumours (OTs). Deletion mapping studies in OTs have revealed multiple commonly deleted regions on chromosome 1p, suggesting that there are more than one tumour suppressor gene. To map critical deletion regions on 1p, a series of 25 OTs were examined for loss of heterozygosity (LOH) on 19 polymorphic markers across the 1p arm using microsatellite analysis. Our study revealed that 60% of tumours had LOH of all informative markers on 1p and identified one tumour showing LOH at telomeric markers only. Since this deletion region lies in one of the critical deletion intervals defined previously, we then screened another series of 27 OTs specifically at 1p36.3 for LOH using nine polymorphic markers. A total of 12% (six out of 52) of tumours were found to carry interstitial deletions. The allelic status and the deletion breakpoints in these tumours with interstitial deletion were further verified by fluorescent in situ hybridisation. The small overlapping intervals facilitated the delineation of two contiguous minimally deleted regions of 0.76 Mb, defined by D1S468 and D1S2845, and of 0.41 Mb, bound by D1S2893 and D1S1608, on 1p36.31–36.32. Based on current reference human genome sequence these deletion regions have been sequenced almost to entirety and contain eight annotated genes. TP73, DFFB and SHREW1 are the only known genes located in these deletion regions, while the others are uncharacterised novel genes. In conclusion, our study has narrowed down the critical tumour suppressor loci on 1p36.3, in which two minimally deleted regions are mapped, and markedly reduced the number of candidate genes to be screened for their involvement in OT development.

A putative new endophytic nitrogen-fixing bacterium Pantoea sp. from sugarcane

AIMS

To isolate and identify endophytic nitrogen-fixing bacteria in sugarcane growing in Cuba without chemical fertilizers.

METHODS AND RESULTS

Two N2-fixing isolates, 9C and T2, were obtained from surface-sterilized stems and roots, respectively, of sugarcane variety ML3-18. Both isolates showed acetylene reduction and H2 production in nitrogen-free media. Nitrogenase activity measured by H2 production was about 15 times higher for isolate 9C than for T2 or for Gluconoacetobacter diazotrophicus (PAL-5 standard strain, ATCC 49037). The nifH gene segment was amplified from both isolates using specific primers. Classification of both T2 and 9C was made on the basis of morphological, biochemical, PCR tests and 16S rDNA sequence analysis.

CONCLUSIONS

Isolate 9C was identified as a Pantoea species from its 16S rDNA, but showed considerable differences in physiological properties from previously reported species of this genus. For example, 9C can be cultured over a wide range of temperature, pH and salt concentration, and showed high H2 production (up to 67.7 nmol H2 h(-1) 10(10) cell(-1)). Isolate T2 was a strain of Gluconacetobacter diazotrophicus.

SIGNIFICANCE AND IMPACT OF THE STUDY

A new N2-fixing endophyte, i.e. Pantoea, able to produce H2 and to grow in a wide range of conditions, was isolated from sugarcane stem tissue and characterized. The strain with these attributes may well be valuable for agriculture.

RAPD polymorphisms in spring wheat cultivars and lines with different level of Fusarium resistance

Random amplified polymorphic DNA (RAPD) markers have been used to characterize the genetic diversity among 35 spring wheat cultivars and lines with different levels of Fusarium resistance. The objectives of this study were to determine RAPD-based genetic similarity between accessions and to derive associations between Fusarium head blight (FHB) and RAPD markers. Two bulked DNA from either highly resistant lines or susceptible lines were used to screen polymorphic primers. Out of 160 screened primers, 17 primers generated reproducible and polymorphic fragments. Genetic similarity calculated from the RAPD data ranged from 0.64 to 0.98. A dendrogram was prepared on the basis of a similarity matrix using the UPGMA algorithm, which corresponded well with the results of principal component analysis and separated the 35 genotypes into two groups. Association analysis between RAPD markers and the FHB index detected three RAPD markers, H19(1000), F2(500) and B1(2400), significantly associated with FHB-resistant genotypes. These results suggest that a collection of unrelated genotypes can be used to identify markers linked to an agronomically important quantitative trait like FHB. These markers will be useful for marker-assistant breeding and can be used as candidate markers for further gene mapping and cloning.

Evidence for protection of nitrogenase from O(2) by colony structure in the aerobic diazotroph Gluconacetobacter diazotrophicus

Gluconacetobacter diazotrophicus is an endophytic diazotroph of sugarcane which exhibits nitrogenase activity when growing in colonies on solid media. Nitrogenase activity of G. diazotrophicus colonies can adapt to changes in atmospheric partial pressure of oxygen (pO(2)). This paper investigates whether colony structure and the position of G. diazotrophicus cells in the colonies are components of the bacterium's ability to maintain nitrogenase activity at a variety of atmospheric pO(2) values. Colonies of G. diazotrophicus were grown on solid medium at atmospheric pO(2) of 2 and 20 kPa. Imaging of live, intact colonies by confocal laser scanning microscopy and of fixed, sectioned colonies by light microscopy revealed that at 2 kPa O(2) the uppermost bacteria in the colony were very near the upper surface of the colony, while the uppermost bacteria of colonies cultured at 20 kPa O(2) were positioned deeper in the mucilaginous matrix of the colony. Disruption of colony structure by physical manipulation or due to 'slumping' associated with colony development resulted in significant declines in nitrogenase activity. These results support the hypothesis that G. diazotrophicus utilizes the path-length of colony mucilage between the atmosphere and the bacteria to achieve a flux of O(2) that maintains aerobic respiration while not inhibiting nitrogenase activity.

[The relationship between surgical staging, pathologic grading, operative type and postoperative recurrence in giant cell tumor of bone]

Sixty-eight surgical procedures of 58 patients with Giant Cell Tumor of Bone(GCT) were followed up over two years. The recurrence rate of GCT was Stage 1: 0 in 5, Stage 2: 15.4% in 39 and Stage 3: 37.5% in 24. It was significantly higher in Stage 3 than in Stage 2 (P < 0.05). The recurrence rate of GCT in Stage 2 was 30.8% in 13 intralesional curettage, and 0 in 17 wide or radical resection(P < 0.05). We conclude that the surgical staging of GCT has important value in predicting postoperative recurrence, in accurately evaluating the operative efforts and in guiding treatment, and that the operative type is a significant factor effecting on the recurrence of GCT.

Completion of base excision repair by mammalian DNA ligases

Three mammalian genes encoding DNA ligases--LIG1, LIG3, and LIG4--have been identified. Genetic, biochemical, and cell biology studies indicate that the products of each of these genes play a unique role in mammalian DNA metabolism. Interestingly, cell lines deficient in either DNA ligase I (46BR.1G1) or DNA ligase III (EM9) are sensitive to simple alkylating agents. One interpretation of these observations is that DNA ligases I and III participate in functionally distinct base excision repair (BER) subpathways. In support of this idea, extracts from both DNA ligase-deficient cell lines are defective in catalyzing BER in vitro and both DNA ligases interact with other BER proteins. DNA ligase I interacts directly with proliferating cell nuclear antigen (PCNA) and DNA polymerase beta (Pol beta), linking this enzyme with both short-patch and long-patch BER. In somatic cells, DNA ligase III alpha forms a stable complex with the DNA repair protein Xrcc1. Although Xrcc1 has no catalytic activity, it also interacts with Pol beta and poly(ADP-ribose) polymerase (PARP), linking DNA ligase III alpha with BER and single-strand break repair, respectively. Biochemical studies suggest that the majority of short-patch base excision repair events are completed by the DNA ligase III alpha/Xrcc1 complex. Although there is compelling evidence for the participation of PARP in the repair of DNA single-strand breaks, the role of PARP in BER has not been established.

Transactivation of the epidermal growth factor receptor is involved in 12-O-tetradecanoylphorbol-13-acetate-induced signal transduction

The mechanism of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced tumor promotion is still not well understood even though it is thought to be related to the protein kinase C/mitogen-activated protein kinase/AP-1 pathway. Recently, TPA was also found to induce epidermal growth factor receptor (EGFR) activity. Here, we investigated whether the EGFR is a necessary component for TPA-induced signal transduction associated with tumor promotion. We demonstrated that potent inhibitors of the EGFR, PD153035 and AG1478, blocked TPA-induced phosphorylation of extracellular signal-regulated kinases (ERKs), AP-1 activity, and cell transformation. Egfr gene deficiency blocked TPA-induced ERK activity and AP-1 binding activity. The blocking of the ectodomain of the EGFR by a monoclonal antibody depressed TPA-induced ERK activity and AP-1 DNA binding activity. The use of a neutralizing antibody for heparin-binding EGF, one of the ligands of EGFR, blocked TPA-induced phosphorylation of ERKs. BB-94, a potent inhibitor of matrix metalloproteinases, which are activators of ectodomain shedding of EGFR ligands, also blocked TPA-induced ERK activity, AP-1 DNA binding, and cell transformation but had no effect on EGF-induced signal transduction. Anti-EGFR, anti-heparin-binding EGF, and BB-94 each blocked TPA-induced EGFR phosphorylation, but only anti-EGFR could block EGF-induced EGFR phosphorylation. Based on these results, we conclude that the EGFR is required for mediating TPA-induced signal transduction. EGFR transactivation induced by TPA is a mechanism by which the EGFR mediates TPA-induced tumor promotion-related signal transduction.

Inhibitory mechanisms of tea polyphenols on the ultraviolet B-activated phosphatidylinositol 3-kinase-dependent pathway

In this study, we investigated the effect of tea polyphenols, (-)-epigallocatechin-3-gallate or theaflavins, on UVB-induced phosphatidylinositol 3-kinase (PI3K) activation in mouse epidermal JB6 Cl 41 cells. Pretreatment of cells with these polyphenols inhibited UVB-induced PI3K activation. Furthermore, UVB-induced activation of Akt and ribosomal p70 S6 kinase (p70 S6-K), PI3K downstream effectors, were also attenuated by the polyphenols. In addition to LY294002, a PI3K inhibitor, pretreatment with a specific mitogen-activated protein/extracellular signal-regulated protein kinases (Erks) kinase 1 inhibitor, U0126, or a specific p38 kinase inhibitor, SB202190, blocked UVB-induced activation of both Akt and p70 S6-K. Pretreatment with LY294002 restrained UVB-induced phosphorylation of Erks, suggesting that in UVB signaling, the Erk pathway is mediated by PI3K. Moreover, pretreatment with rapamycin, an inhibitor of p70 S6-K, inhibited UVB-induced activation of p70 S6-K, but UVB-induced activation of Akt did not change. Interestingly, UVB-induced p70 S6-K activation was directly blocked by the addition of (-)-epigallocatechin-3-gallate or theaflavins, whereas these polyphenols showed only a weak inhibition on UVB-induced Akt activation. Because PI3K is an important factor in carcinogenesis, the inhibitory effect of these polyphenols on activation of PI3K and its downstream effects may further explain the anti-tumor promotion action of these tea constituents.

Expression of cathepsins B, D and L in mouse corneas infected with Pseudomonas aeruginosa

C57BL/6J naïve and immunized mice were intracorneally infected with Pseudomonas aeruginosa. Semi-quantitative RT-PCR was performed to detect cathepsin gene expression and the results were further confirmed by immunoblot analysis. The enzymatic activities of cathepsins B, D and L were measured by peptidase assays. Immunohistochemical staining was carried out to localize the expression of the cathepsins. Cathepsins B, D and L were detected in the normal cornea by RT-PCR. A peptidase assay revealed activities of all three cathepsins under normal physiological conditions. In naïve mice, enzymatic activities of cathepsins B, D and L were all significantly enhanced when the corneas were infected with P. aeruginosa and the peak of the induction appeared around day 6 postinfection. Immunoblot analysis showed increased expression of cathepsins B, D and L. The infected corneal samples from immunized mice exhibited much lower induction of enzymatic activities compared to those from naïve mice. Immunohistochemistry showed that the expression of cathepsins in the normal cornea was restricted to the epithelial tissue while the induced expression of cathepsins was predominantly in the substantia propria. Our data revealed up-regulated enzymatic activities of cathepsins B, D and L in the naïve corneas infected with P. aeruginosa, which correlated well with the inflammatory response. Immunization of mice against P. aeruginosa attenuated the inducing effect on cathepsin expression caused by infection. The time sequence for induction of cathepsin proteins and enzymatic activities suggests a mechanism of host proteolytic degradation of the extracellular matrix resulting in corneal destruction after P. aeruginosa infection.

Induction of EGFR-dependent and EGFR-independent signaling pathways by ultraviolet A irradiation

Most of the signal pathways involved in ultraviolet (UV)-induced skin carcinogenesis are thought to originate at plasma membrane receptors. However, UVA-induced signal transduction to downstream ribosomal protein S6 kinases, p70(S6K) and p90(RSK), is not well understood. In this report, we show that UVA stimulation of the epidermal growth factor receptor (EGFR) may lead to activation of p70(S6K)/p90(RSK) through phosphatidyl isositol (PI)-3 kinase and extracellular receptor-activated kinases (ERKs). Evidence is provided that phosphorylation and activation of p70(S6K)/p90(RSK) induced by UVA were prevented in Egfr(-/-) cells and were also markedly inhibited by the EGFR-specific tyrosine kinase inhibitors AG1478 and PD153035. Furthermore, EGFR tyrosine kinase inhibitors and EGFR deficiency significantly suppressed activation of PI-3 kinase and ERKs in regulating activation of p90(RSK)/p70(S6K) but had no effect on activation of c-Jun NH(2)-terminal kinases (JNKs) and p38 kinase in response to UVA. Thus, our results suggest that UVA-induced EGFR signaling may be required for activation of p90(RSK)/p70(S6K), PI-3 kinase, and ERKs but not JNKs or p38 kinase.

[Nasal cavity dimensions in the infants measured with acoustic rhinometry]

OBJECTIVE

To investigate the range of normal value of minimal cross-sectional area (MCA) of the nasal cavity, distance of minimal cross-sectional area from the nostril (DCA), total nasal cavity volume(NV) and total nasopharyngeal cavity volume (NPV) of healthy infants.

METHOD

One hundred and seventy-five healthy infants and one hundred and eight infants suffered from acute upper respiratory tract infection were measured with acoustic rhinometry.

RESULT

The range of total MCA of healthy infants was 0.2-0.5 (cm)2, DCA was 1.93-2.47 cm, NV was 2.69-4.75 cm3 and NPV was 3.83-8.92 cm3. Comparing healthy infants with infants suffered from acute upper respiratory tract infection, there all were significant differences in MCA, DCA and NV.

CONCLUSION

Acoustic rhinometry suit objective assessment of the nasal airways in infants. It is demonstrated that these data can provide available information for the study of nasal physiology and pathophysiology, well as for the diagnosis and judgement of therapeutic effectiveness of nasal diseases.

Expression of membrane-type matrix metalloproteinases 4, 5, and 6 in mouse corneas infected with P. aeruginosa

PURPOSE

To investigate the expression and regulation of membrane-type matrix metalloproteinases (MT-MMPs) 4, 5, and 6 in the mouse corneas infected with Pseudomonas aeruginosa.

METHODS

C57BL/6J mice were intracorneally infected with P. aeruginosa. The expression of MT4-, MT5-, and MT6-MMP was detected at both the mRNA and protein levels by RT-PCR and immunoblot analysis. Immunohistochemical staining was performed to localize the expression of MT4- and MT5-MMP in the mouse corneas.

RESULTS

Expression of MT4- and MT5-MMP was detected in the normal (uninfected) cornea by RT-PCR and immunoblot analysis. When infected with P. aeruginosa, the corneas showed significant induction of each MT-MMP. Localization of MT4- and MT5-MMP revealed that the expression of MT5-MMP was restricted to the epithelial tissue in the normal cornea, whereas the induced expression of MT4- and MT5-MMP was predominantly in the substantia propria, which contained most of the infiltrating cells. MT6-MMP expression was not detected in the uninfected cornea but was upregulated in the infected corneas.

CONCLUSIONS

Expression of MT4-, MT5-, and MT6-MMP was induced in corneas infected with P. aeruginosa. Immunohistochemistry showed predominant immunoreactivity of MT4- and MT5-MMP in the substantia propria. Previous histologic studies have revealed different patterns of inflammatory cell infiltration with an increased number of polymorphonuclear neutrophils (PMNs) during the early stage of inflammation and increased macrophages during the late stage. These results indicate a good correlation between the overexpression of the MT-MMPs in the infected corneas and the inflammatory response-that is, leukocyte infiltration-indicating that inflammatory cells such as macrophages and PMNs may play a role in the upregulation of MT-MMPs during corneal infection, which in turn can cause the destruction of corneal tissue.

cDNA cloning and promoter analysis of rat caspase-9

Caspase-9 is the apex caspase of the mitochondrial pathway of apoptosis, which plays a critical role in apoptotic initiation and progression. However, gene regulation of caspase-9 is largely unknown. This is in part due to the lack of information on the gene promoter. Here we have cloned the full-length cDNA of rat caspase-9 and have isolated promoter regions of this gene. The rat caspase-9 cDNA of 2058 bp predicts a protein of 454 amino acids, which contains a caspase-recruitment domain ('CARD') at the N-terminus and enzymic domains at the C-terminus. The enzyme's active site, with a characteristic motif of QACGG, was also identified. Overall, rat and human caspase-9 have 71% identity. With the cDNA sequence, we subsequently isolated the proximal 5'-flanking regions of rat caspase-9 by the procedure of genomic walking. The 2270 bp genomic segment is 'TATA-less', but contains several GC boxes. Elements binding known transcription factors such as Sp-1, Pit-1, CCAAT-enhancer-binding protein (C/EBP), glucocorticoid receptor and hypoxia-inducible factor 1 (HIF-1) were also identified. When cloned into reporter gene vectors, the genomic segment showed significant promoter activity, indicating that the 5'-flanking regions isolated by genomic walking contain the gene promoter of rat caspase-9. Of significance is that the cloned promoter segments were activated by severe hypoxia, conditions inducing caspase-9 transcription. Thus, the genomic sequences reported here contain not only the basal promoter of rat caspase-9 but also regulatory elements responsive to pathophysiological stimuli including hypoxia.

Cannabinoid-receptor-independent cell signalling by N-acylethanolamines

Anandamide and other polyunsaturated N-acylethanolamines (NAEs) exert biological activity by binding to cannabinoid receptors. These receptors are linked to G(i/o) proteins and their activation leads to extracellular-signal-regulated protein kinase (ERK) and c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAP kinase) activation, inhibition of cAMP-dependent signalling and complex changes in the expression of various genes. Saturated and monounsaturated NAEs cannot bind to cannabinoid receptors and may thus mediate cell signalling through other targets. Here we report that both saturated/monounsaturated NAEs and anandamide (20:4(n-6) NAE) stimulate cannabinoid-receptor-independent ERK phosphorylation and activator protein-1 (AP-1)-dependent transcriptional activity in mouse epidermal JB6 cells. Using a clone of JB6 P(+) cells with an AP-1 collagen-luciferase reporter construct, we found that 16:0, 18:1(n-9), 18:1(n-7), 18:2(n-6) and 20:4(n-6) NAEs stimulated AP-1-dependent transcriptional activity up to 2-fold, with maximal stimulation at approx. 10-15 microM. Higher NAE concentrations had toxic effects mediated by alterations in mitochondrial energy metabolism. The AP-1 stimulation appeared to be mediated by ERK but not JNK or p38 signalling pathways, because all NAEs stimulated ERK1/ERK2 phosphorylation without having any effect on JNK or p38 kinases. Also, overexpression of dominant negative ERK1/ERK2 kinases completely abolished NAE-induced AP-1 activation. In contrast with 18:1(n-9) NAE and anandamide, the cannabinoid receptor agonist WIN 55,212-2 did not stimulate AP-1 activity and inhibited ERK phosphorylation. The NAE-mediated effects were not attenuated by pertussis toxin and appeared to be NAE-specific, as a close structural analogue, oleyl alcohol, failed to induce ERK phosphorylation. The data support our hypothesis that the major saturated and monounsaturated NAEs are signalling molecules acting through intracellular targets without participation of cannabinoid receptors.

Type 1 von Willebrand disease mutation Cys1149Arg causes intracellular retention and degradation of heterodimers: a possible general mechanism for dominant mutations of oligomeric proteins

Some families affected by von Willebrand disease type 1 show high penetrance with exceptionally low von Willebrand factor (VWF) levels. Previously, a mutation associated with this dominant phenotype, Cys1149Arg, was found to decrease the secretion of coexpressed normal VWF, and the mutation was proposed to cause intracellular retention of pro-VWF heterodimers. To demonstrate heterodimer formation, a model was developed in which subunits could be distinguished immunologically and by size. Recombinant VWF lacking domain A1 (dA1), A3 (dA3), or both (dA13) was secreted efficiently as a full range of multimers. Cotransfection of Cys1149Arg and dA13 resulted in the secretion of multimeric VWF containing about 250 kd (Cys1149Arg) and about 210 kd (dA13). Cell lysates contained pro-VWF forms of Cys1149Arg and dA13. Immunoprecipitation with an antidomain A1 antibody recovered both subunits in heterodimers, and subunit ratios were consistent with random dimerization. Similar results were obtained for cotransfection of Cys1149Arg and dA1. Normal VWF has a Cys1149-Cys1169 intrachain bond. When cotransfected with normal VWF, Cys1149Arg or the double mutant Cys1149Arg+Cys1169Ser caused a similar decrease in VWF secretion, suggesting that an unpaired Cys1169 does not explain the intracellular retention of Cys1149Arg. VWF Cys1149Arg was not secreted from BHK cells but was degraded intracellularly within about 4 hours, and the proteasome inhibitor lactacystin delayed its clearance more than 16 hours. Thus, dominant von Willebrand disease type 1 may be caused by heterodimerization of mutant and normal subunits in the endoplasmic reticulum followed by proteasomal degradation in the cytoplasm. A similar dominant negative mechanism could cause quantitative deficiencies of other multisubunit proteins.

MSK1 and JNKs mediate phosphorylation of STAT3 in UVA-irradiated mouse epidermal JB6 cells

Phosphorylation of Tyr(705) and Ser(727) of signal transducer and activator of transcription 3 (STAT3) are known to be required for maximal activation by diverse stimuli. Tyr(705) phosphorylation is generally accepted to be mediated by the Janus kinase family. But the mechanism for STAT3 (Ser(727)) phosphorylation is not well understood. Here, we provide evidence that UVA-induced phosphorylation of STAT3 at Ser(727) is inhibited by pretreatment of JB6 cells with PD98059 or SB202190. Phosphorylation of STAT3 (Ser(727)) is also markedly prevented by a dominant negative mutant of ERK2, c-Jun N-terminal kinase 1 (JNK1), or p38 kinase and in knockout Jnk1(-/-) or Jnk2(-/-) cells. Furthermore, STAT3 (Ser(727)) phosphorylation is suppressed by C- or N-terminal "kinase-dead" mutants of mitogen- and stress-activated protein kinase 1 (MSK1), a downstream kinase of ERKs and p38 kinase, and H89, a potential MSK1 inhibitor. In vitro experiments showed that active MSK1 and JNKs, but not ERKs or p38 kinase, phosphorylate STAT3 (Ser(727)). Additionally, the role of MAPKs in mediating UVA-stimulated DNA binding activity of STAT3 was investigated. Overall, these results suggest that UVA-induced Ser(727) phosphorylation of STAT3 may occur through MSK1 and JNKs.

Anatomic basis of vascularized ulnar nerve graft by the pedicle of the superior collateral ulnar artery

OBJECTIVE

To investigate the anatomic basis of vascularized ulnar nerve graft by the pedicle of the superior collateral ulnar artery (SCUA).

METHODS

Twenty-two fresh cadaver upper extremities injected i ntra-arterially with latex were dissected to study the extrinsic blood supply of the ulnar nerve. Other 6 fresh upper extremities were used to analyze the blood supply range of SCUA inside the ulnar nerve by microangiographic and histological methods.

RESULTS

The ulnar nerve was supplied by a branch of the lateral thoracic artery or directly by the axillary artery in the axillary section, by b ranches of SCUA in the upper arm, and by branches from the anastomosis of the collateral arteries and the posterior branch of the recurrent ulnar artery in the elbow. SCUA could supply the whole ulnar nerve from the axilla to the wrist.

CONCLUSIONS

The ulnar nerve can be used as a vascularized nerve graft by the pedicle of SCUA in treatment of brachial plexus roots avulsion by C7 transfer from healthy side.

Transforming growth factor beta (TGFbeta) mediates Schwann cell death in vitro and in vivo: examination of c-Jun activation, interactions with survival signals, and the relationship of TGFbeta-mediated death to Schwann cell differentiation

In some situations, cell death in the nervous system is controlled by an interplay between survival factors and negative survival signals that actively induce apoptosis. The present work indicates that the survival of Schwann cells is regulated by such a dual mechanism involving the negative survival signal transforming growth factor beta (TGFbeta), a family of growth factors that is present in the Schwann cells themselves. We analyze the interactions between this putative autocrine death signal and previously defined paracrine and autocrine survival signals and show that expression of a dominant negative c-Jun inhibits TGFbeta-induced apoptosis. This and other findings pinpoint activation of c-Jun as a key downstream event in TGFbeta-induced Schwann cell death. The ability of TGFbeta to kill Schwann cells, like normal Schwann cell death in vivo, is under a strong developmental regulation, and we show that the decreasing ability of TGFbeta to kill older cells is attributable to a decreasing ability of TGFbeta to phosphorylate c-Jun in more differentiated cells.

Immortalization of human WI38 cells is associated with differential activation of the c-myc origins

To study the possible relationships between origin activities and cellular processes leading to malignancy, we used an isogenic system of human embryo lung fibroblast cells WI38 and a SV40-transformed variant, WI38 VA13 2RA (WI38(SV40)). We found that the activities of all initiation sites at the c-myc locus were approximately two-fold as high in WI38(SV40) cells as in WI38 cells. Thus, higher initiation frequency of origins at certain loci is induced with cell immortalization, one of the steps in the multi-step process leading to malignancy. We measured the activities of the four c-myc promoters P0, P1, P2, and P3 with nuclear runon assay in the two cell lines in order to detect potential individual promoter changes that may be also associated with immortalization by SV40 virus. The results show that the activities of the promoters P0, P1, and P3 did not significantly change, but the activity of the major promoter P2 in WI38(SV40) cells was about 7.5- to 8.0-fold as high as that in WI38 cells. The increased activity of promoter P2, although approximately 600 bp downstream of one of the major DNA replication initiation sites, had no preferential influence on the major sites of origin activity. Since the distribution of nascent strand abundance was not significantly altered, binding of transcription factors does not seem to facilitate the assembly of pre-replication complex (pre-RC) or otherwise preferentially alter the activities of the DNA replication proteins at this major initiation site.

[Expression and distribution of Aquaporin 1 in the nasal polyps]

OBJECTIVE

To confirm the expression and distribution of Aquaporin 1 (AQP1) in the nasal polyps and to investigate the relation between AQP1 and the nasal polyp edema.

METHODS

fourteen cases of normal inferior turbinates and 26 cases of nasal polyps were used. The expression and distribution of AQP1 in nasal polyps were examined by immunohistochemical technique.

RESULTS

The level of AQP1 in the epithelial cells and serous cells from nasal polyps was higher than that in inferior turbinates, and the level of AQP1 in the epithelial cells and cilium cells from inferior turbinate was higher than that in nasal polyps.

CONCLUSION

There is close relationship between AQP1 and nasal polyp edema.

Inhibition of arsenite-induced apoptosis by aspirin

Arsenite exposure and subsequent arsenite-induced toxicity and carcinogenesis are common in many countries. Thus the study of chemopreventive compounds that inhibit arsenite-induced toxicity and carcinogenesis is very valuable. In the present work, we investigated the effect of aspirin on arsenite-induced apoptosis and signal transduction by means of luciferase activity, apoptosis analysis and Western blotting. Arsenite induced AP-1 transcriptional activity at the same concentration (20 microM) as was effective for inducing apoptosis. Arsenite-induced apoptosis and AP-1 transactivation in JB6 cells were blocked by aspirin and salicylate (SA). Both aspirin and SA inhibited arsenite-induced phosphorylation of Erks, but had no effect on phosphorylation of JNKs. SA inhibited arsenite-induced phosphorylation of p38 kinase, but aspirin did not. These results indicate that aspirin and SA inhibit arsenite-induced apoptosis through the inhibition of the Erks/AP-1 pathway.

Mechanisms of inhibition of the Ras-MAP kinase signaling pathway in 30.7b Ras 12 cells by tea polyphenols (-)-epigallocatechin-3-gallate and theaflavin-3,3'-digallate

Our previous study showed that tea polyphenols inhibited MAP kinase and AP-1 activities in mouse epidermal JB6 cells and the corresponding H-ras-transformed cell line 30.7b Ras 12. The present study investigated the mechanisms of this inhibition. The cells were incubated with (-)-epigallocatechin-3-gallate (EGCG) or theaflavin-3,3'-digallate (TFdiG) (20 mM) for different times, and the cell lysate was analyzed by immunoblotting. EGCG treatment decreased the levels of phospho-Erk1/2 and -MEK1/2 time-dependently (by 60% at 60 min). TFdiG lowered their levels by 38%-50% at 15 min. TFdiG effectively decreased total Raf-1 protein levels, most likely through lysosomal degradation. EGCG did not affect protein levels or the activity of Raf-1 significantly but decreased its association with MEK1 as determined by co-immunoprecipitation. In addition, EGCG and TFdiG (10 mM) inhibited the phosphorylation of Elk-1 by isolated phospho-Erk1/2 in vitro. This inhibition of Erk1/2 activity is Elk-1 concentration-dependent and ATP concentration-independent, which suggests that EGCG and TFdiG interfere with the binding of the protein substrate to the kinase. The presently demonstrated specific mechanisms of inhibition of MAP kinases by EGCG and TFdiG may help us to understand the effects of tea consumption on cancer, inflammatory diseases, and cardiovascular diseases.