Semiautomated volumetric measurement on postcontrast MR imaging for analysis of recurrent and residual disease in glioblastoma multiforme

BACKGROUND AND PURPOSE

A limitation in postoperative monitoring of patients with glioblastoma is the lack of objective measures to quantify residual and recurrent disease. Automated computer-assisted volumetric analysis of contrast-enhancing tissue represents a potential tool to aid the radiologist in following these patients. In this study, we hypothesize that computer-assisted volumetry will show increased precision and speed over conventional 1D and 2D techniques in assessing residual and/or recurrent tumor.

MATERIALS AND METHODS

This retrospective study included patients with native glioblastomas with MR imaging performed at 24-48 hours following resection and 2-4 months postoperatively. 1D and 2D measurements were performed by 2 neuroradiologists with Certificates of Added Qualification. Volumetry was performed by using manual segmentation and computer-assisted volumetry, which combines region-based active contours and a level set approach. Tumor response was assessed by using established 1D, 2D, and volumetric standards. Manual and computer-assisted volumetry segmentation times were compared. Interobserver correlation was determined among 1D, 2D, and volumetric techniques.

RESULTS

Twenty-nine patients were analyzed. Discrepancy in disease status between 1D and 2D compared with computer-assisted volumetry was 10.3% (3/29) and 17.2% (5/29), respectively. The mean time for segmentation between manual and computer-assisted volumetry techniques was 9.7 minutes and <1 minute, respectively (P < .01). Interobserver correlation was highest for volumetric measurements (0.995; 95% CI, 0.990-0.997) compared with 1D (0.826; 95% CI, 0.695-0.904) and 2D (0.905; 95% CI, 0.828-0.948) measurements.

CONCLUSIONS

Computer-assisted volumetry provides a reproducible and faster volumetric assessment of enhancing tumor burden, which has implications for monitoring disease progression and quantification of tumor burden in treatment trials.

MicroRNA-21 regulates T-cell apoptosis by directly targeting the tumor suppressor gene Tipe2

MicroRNAs (MiRs) are short noncoding RNAs that can regulate gene expression. It has been reported that miR-21 suppresses apoptosis in activated T cells, but the molecular mechanism remains undefined. Tumor suppressor Tipe2 (or tumor necrosis factor-α-induced protein 8 (TNFAIP8)-like 2 (TNFAIP8L2)) is a newly identified anti-inflammatory protein of the TNFAIP8 family that is essential for maintaining immune homeostasis. We report here that miR-21 is a direct target of nuclear factor-κB and could regulate Tipe2 expression in a Tipe2 coding region-dependent manner. In activated T cells and macrophages, Tipe2 expression was markedly downregulated, whereas miR-21 expression was upregulated. Importantly, Tipe2-deficient T cells were significantly less sensitive to apoptosis. Conversely, overexpression of Tipe2 in EL-4 T cells increased their susceptibility to activation-induced apoptosis. Therefore, Tipe2 provides a molecular bridge between miR-21 and cell apoptosis; miR-21 suppresses apoptosis in activated T cells at least in part through directly targeting tumor suppressor gene Tipe2.

Repression of BIM mediates survival signaling by MYC and AKT in high-risk T-cell acute lymphoblastic leukemia

Treatment resistance in T-cell acute lymphoblastic leukemia (T-ALL) is associated with phosphatase and tensin homolog (PTEN) deletions and resultant phosphatidylinositol 3'-kinase (PI3K)-AKT pathway activation, as well as MYC overexpression, and these pathways repress mitochondrial apoptosis in established T-lymphoblasts through poorly defined mechanisms. Normal T-cell progenitors are hypersensitive to mitochondrial apoptosis, a phenotype that is dependent on the expression of proapoptotic BIM. In a conditional zebrafish model, MYC downregulation induced BIM expression in T-lymphoblasts, an effect that was blunted by expression of constitutively active AKT. In human T-ALL cell lines and treatment-resistant patient samples, treatment with MYC or PI3K-AKT pathway inhibitors each induced BIM upregulation and apoptosis, indicating that BIM is repressed downstream of MYC and PI3K-AKT in high-risk T-ALL. Restoring BIM function in human T-ALL cells using a stapled peptide mimetic of the BIM BH3 domain had therapeutic activity, indicating that BIM repression is required for T-ALL viability. In the zebrafish model, where MYC downregulation induces T-ALL regression via mitochondrial apoptosis, T-ALL persisted despite MYC downregulation in 10% of bim wild-type zebrafish, 18% of bim heterozygotes and in 33% of bim homozygous mutants (P=0.017). We conclude that downregulation of BIM represents a key survival signal downstream of oncogenic MYC and PI3K-AKT signaling in treatment-resistant T-ALL.

Src regulates angiogenic factors and vascular permeability after focal cerebral ischemia-reperfusion

Developing new strategies to treat cerebral ischemic-reperfusion injury will require a better understanding of the mechanisms that underlie vascular permeability. In this study we examined the temporal expression of Src and angiogenic factors in rat brain after focal cerebral ischemia and reperfusion and analyzed the relationships among those factors. We also investigated the effect of Src inhibitor PP1 (4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine) in ischemic reperfusion. Rats were subjected to middle cerebral artery occlusion for 90 min followed by reperfusion with or without PP1 treatment. Src mRNA increased at 3h after reperfusion and then gradually declined. Phosphorylation of Src at Y418 displayed a biphasic increase. Phosphorylation increased as early as 3h and peaked at 6h; after decreasing, it peaked again at 3-7 days. Increases in Src mRNA and phosphorylation correlated positively with levels of vascular endothelial growth factor (VEGF) and angiopoietin-2 (Ang-2), and negatively with levels of angiopoietin-1 (Ang-1) and zonula occludens-1 (ZO-1). Changes in the expression of these factors correlated with the progress of vascular permeability, especially early after reperfusion. Hence, dynamic temporal changes in Src Y418 phosphorylation may modulate vascular permeability after cerebral ischemia and reperfusion. PP1 effectively decreased Src Y418 phosphorylation and the expression of VEGF and Ang-2 and increased the expression of Ang-1 and ZO-1. It also reduced cerebral infarct size and neurologic dysfunction. Therefore, Src may represent a new therapeutic target for reducing tissue damage caused by increased vascular permeability.

Pin1 modulates p63α protein stability in regulation of cell survival, proliferation and tumor formation

The homolog of p53 gene, p63, encodes multiple p63 protein isoforms. TAp63 proteins contain an N-terminal transactivation domain similar to that of p53 and function as tumor suppressors; whereas ΔNp63 isoforms, which lack the intact N-terminal transactivation domain, are associated with human tumorigenesis. Accumulating evidence demonstrating the important roles of p63 in development and cancer development, the regulation of p63 proteins, however, is not fully understood. In this study, we show that peptidyl-prolyl isomerase Pin1 directly binds to and stabilizes TAp63α and ΔNp63α via inhibiting the proteasomal degradation mediated by E3 ligase WWP1. We further show that Pin1 specifically interacts with T₅₃₈P which is adjacent to the P₅₅₀PxY₅₄₃ motif, and disrupts p63α–WWP1 interaction. In addition, while Pin1 enhances TAp63α-mediated apoptosis, it promotes ΔNp63α-induced cell proliferation. Furthermore, knockdown of Pin1 in FaDu cells inhibits tumor formation in nude mice, which is rescued by simultaneous knockdown of WWP1 or ectopic expression of ΔNp63α. Moreover, overexpression of Pin1 correlates with increased expression of ΔNp63α in human oral squamous cell carcinoma samples. Together, these results suggest that Pin1-mediated modulation of ΔNp63α may have a causative role in tumorigenesis.

Dense nuclei segmentation based on graph cut and convexity-concavity analysis

With the rapid advancement of 3D confocal imaging technology, more and more 3D cellular images will be available. However, robust and automatic extraction of nuclei shape may be hindered by a highly cluttered environment, as for example, in fly eye tissues. In this paper, we present a novel and efficient nuclei segmentation algorithm based on the combination of graph cut and convex shape assumption. The main characteristic of the algorithm is that it segments nuclei foreground using a graph-cut algorithm with our proposed new initialization method and splits overlapping or touching cell nuclei by simple convexity and concavity analysis. Experimental results show that the proposed algorithm can segment complicated nuclei clumps effectively in our fluorescent fruit fly eye images. Evaluation on a public hand-labelled 2D benchmark demonstrates substantial quantitative improvement over other methods. For example, the proposed method achieves a 3.2 Hausdorff distance decrease and a 1.8 decrease in the merged nuclei error per slice.

Measurement of two low-temperature energy gaps in the electronic structure of antiferromagnetic USb2 using ultrafast optical spectroscopy

Ultrafast optical spectroscopy is used to study the antiferromagnetic f-electron system USb(2). We observe the opening of two charge gaps at low temperatures (</~45 K), arising from renormalization of the electronic structure. Analysis of our data indicates that one gap is due to hybridization between localized f-electron and conduction electron bands, while band renormalization involving magnons leads to the emergence of the second gap. These experiments thus enable us to shed light on the complex electronic structure emerging at the Fermi surface in f-electron systems.

Brd4 maintains constitutively active NF-κB in cancer cells by binding to acetylated RelA

Acetylation of the RelA subunit of NF-κB at lysine-310 regulates the transcriptional activation of NF-κB target genes and contributes to maintaining constitutively active NF-κB in tumors. Bromodomain-containing factor Brd4 has been shown to bind to acetylated lysine-310 (AcLys310) and to regulate the transcriptional activity of NF-κB, but the role of this binding in maintaining constitutively active NF-κB in tumors remains elusive. In this study, we demonstrate the structural basis for the binding of bromodomains (BDs) of bromodomain-containing protein 4 (Brd4) to AcLys310 and identify the BD inhibitor JQ1 as an effective small molecule to block this interaction. JQ1 suppresses TNF-α-mediated NF-κB activation and NF-κB-dependent target gene expression. In addition, JQ1 inhibits the proliferation and transformation potential of A549 lung cancer cells and suppresses the tumorigenicity of A549 cells in severe combined immunodeficiency mice. Furthermore, we demonstrate that depletion of Brd4 or treatment of cells with JQ1 induces the ubiquitination and degradation of the constitutively active nuclear form of RelA. Our results identify a novel function of Brd4 in maintaining the persistently active form of NF-κB found in tumors, and they suggest that interference with the interaction between acetylated RelA and Brd4 could be a potential therapeutic approach for the treatment of NF-κB-driven cancer.

Synthesis and Interfacial Properties of Dialkylbenzenesulfonates for Producting Low Interfacial Tensions

A new method of synthesis a series of pure dialkylbenzene sulfonates is described. The benzene ring carries a major alkyl substituent, consisting of a linear chain of sixteen carbon atoms long, and one additional methyl group. Products are charactered by EI-MS and 1H NMR. Experimental investigations have been conducted to explore the interfacial tension behavior of crude oil with dialkylbenzenesulfonates. The effects of various parameters such as surfactant concentration, salinity concentration on the interfacial tension of crude oil-water were investigated in detail. The transient low interfacial tensions in crude oil/alkali system were caused by the synergistic effects between surfactant and the active species generated at interface, but surfactant molecules plays the dominant role at equilibrium.

Dispersion and stability of titanium dioxide nanoparticles in aqueous suspension: effects of ultrasonication and concentration

The increasing applications of titanium dioxide (TiO(2)) nanoparticles raise concerns about their potential environmental impacts. To investigate the fate and transport of TiO(2) nanoparticles in aqueous suspension, ultrasonication is widely used for the dispersion of TiO(2) nanoparticles in laboratory-scale studies. There is a pressing need for detailed information on the dispersion and stability of TiO(2) nanoparticles. This study investigated the change of size, zeta potential, and pH of TiO(2) nanoparticles aqueous suspension under different conditions of ultrasonication and concentrations. It was found that the hydrodynamic diameter of TiO(2) nanoparticles decreased with increasing suspension concentration and remained stable for more than 1 hour after sonication, which is enough for experimental research. The pH decreased with increasing nanoparticles concentration. Ultrasonication remarkably improved zeta potential to be above 15 mV for all the samples. Therefore, 20 minutes of ultrasonication (180 W) is sufficient for the dispersion of this rutile TiO(2) nanoparticles suspension, which can remain stable for more than 1 hour. However, the optimum sonication time for TiO(2) nanoparticles dispersion is influenced by many factors, such as TiO(2) nanoparticles concentration, solution chemistry, and sonicator parameters.

Removal of titanium dioxide nanoparticles by coagulation: effects of coagulants, typical ions, alkalinity and natural organic matters

To investigate the possibility of removing titanium dioxide nanoparticles (TiO2 NPs) from water by coagulation, as well as to find the optimal coagulant and experimental conditions for TiO2 NP removal, four types of coagulant were adopted: polyferric sulfate (PFS), ferric chloride (FeCl3), polyaluminum chloride (PACl), and alum (Al2(SO4)3). It was found that the removal of TiO2 NPs by coagulation was affected by ionic strength, alkalinity, as well as types and dosages of coagulants. PFS and FeCl3 achieved much higher removal efficiency of TiO2 NPs than PACl and Al2(SO4)3 did. For 30 mg/L TiO2 NPs, a dosage of 0.3 mM PFS (as Fe) achieved 84% removal after coagulation followed by 30 min settlement. Optimal ionic strength (0.1 M NaCl or 0.03 M CaCl2) is of vital importance for the performance of PFS. Na2SO4 is unfavorable for the performance of PFS. Optimal alkalinity (0.01-0.03 M NaHCO3) is necessary for FeCl3 to remove TiO2 NPs. Natural organic matter, as represented by humic acid (HA) up to 11 mg/L, reduces the removal of TiO2 NPs by coagulation. These findings indicate that coagulation is a good option for the removal of TiO2 NPs from water, and more attention should be paid to the effects of water quality when using coagulation to remove TiO2 NPs from aqueous matrices. This provides a possible solution to alleviate the potential hazard caused by TiO2 NPs.

Differential expression and cellular localization of novel isoforms of the tendon biomarker tenomodulin

Tenomodulin (Tnmd, also called Tendin) is classified as a type II transmembrane glycoprotein and is highly expressed in developing as well as in mature tendons. Along with scleraxis (scx), Tnmd is a candidate marker gene for tenocytes. Its function is unknown, but it has been reported to have anti-angiogenic properties. Results in a knockout mouse model did not substantiate that claim. It has homology to chondromodulin-I. Single nucleotide polymorphisms of TNMD have been associated with obesity, macular degeneration, and Alzheimer's disease in patients. In the present study, three Tnmd isoforms with deduced molecular weights of 20.3 (isoform II), 25.4 (isoform III), and 37.1 (isoform I) kDa were proposed and verified by Western blot from cells with green fluorescent protein-linked, overexpressed constructs, tissue, and by qPCR of isoforms from human tissues and cultured cells. Overexpression of each Tnmd isoform followed by immunofluorescence imaging showed that isoforms I and II had perinuclear localization while isoform III was cytoplasmic. Results of qPCR demonstrated differential expression of each Tnmd isoform in patient's specimens taken from flexor carpi radialis, biceps brachii, and flexor digitorum profundus tendons. Knockdown of Tnmd increased the expression of both scleraxis (scx) and myostatin, indicating a potential negative feedback loop between Tnmd and its regulators. Knockdown of all Tnmd isoforms simultaneously also reduced tenocyte proliferation. I-TASSER protein three-dimensional conformation modeling predictions indicated each Tnmd isoform had different structures and potential functions: isoform 1, modeled as a cytosine methyltransferase; isoform 2, a SUMO-1-like SENP-1 protease; and isoform 3, an α-syntrophin, plextrin homology domain scaffolding protein. Further functional studies with each Tnmd isoform may help us to better understand regulation of tenocyte proliferation, tendon development, response to injury and strain, as well as mechanisms in tendinoses. These results may indicate novel therapeutic targets in specific tenomodulin isoforms as well as treatments for tendon diseases.

Factors influencing the degree of enhancement of prostate cancer on contrast-enhanced transrectal ultrasonography: correlation with biopsy and radical prostatectomy specimens

OBJECTIVES

This study was designed to identify factors that influenced the degree of enhancement of prostate cancer on contrast-enhanced transrectal ultrasonography (CETRUS).

METHODS

139 patients suspected of prostate cancer were evaluated with CETRUS followed by systematic and targeted transrectal ultrasound-guided biopsies. The degree of enhancement of the lesions was objectively measured using peak intensity with time-intensity curve analysis software. Ultrasound findings were correlated with clinical characteristics as well as biopsy and radical prostatectomy findings.

RESULTS

Prostate cancers were detected in 230 biopsy sites from 91 patients. The mean peak intensity value of prostate cancer was significantly higher than that of the benign lesions (9.82 ± 3.73 vs 7.51 ± 2.97; p<0.001), and the peak intensity value of the cancer foci varied across the prostate. The mixed model analysis revealed that the location and Gleason score of tumour foci were the influencing factors of the peak intensity value, and the former had a stronger influence upon peak intensity than the latter (p=0.000 and 0.040, respectively). However, age, prostate volume or serum prostate-specific antigen of the patient had no significant influence on the peak intensity value (p>0.05). Furthermore, the peak intensity value of tumours larger than 5 mm diameter was significantly higher than tumours of 5 mm or smaller diameter (9.28 ± 2.46 vs 6.69 ± 2.65; p<0.001).

CONCLUSIONS

The prostate cancer lesions with a higher Gleason score and larger tumour size which were located in the lateral peripheral zone (PZ) were more likely to show a marked enhancement. Lesions with lower peak intensity that are located in the medial PZ should also be treated as suspicious.

Molecular determinants of U-type inactivation in Kv2.1 channels

Kv2.1 channels exhibit a U-shaped voltage-dependence of inactivation that is thought to represent preferential inactivation from preopen closed states. However, the molecular mechanisms underlying so-called U-type inactivation are unknown. We have performed a cysteine scan of the S3-S4 and S5-P-loop linkers and found sites that are important for U-type inactivation. In the S5-P-loop linker, U-type inactivation was preserved in all mutant channels except E352C. This mutation, but not E352Q, abolished closed-state inactivation while preserving open-state inactivation, resulting in a loss of the U-shaped voltage profile. The reducing agent DTT, as well as the C232V mutation in S2, restored U-type inactivation to the E352C mutant, which suggests that residues 352C and C232 may interact to prevent U-type inactivation. The R289C mutation, in the S3-S4 linker, also reduced U-type inactivation. In this case, DTT had little effect but application of MTSET restored wild-type-like U-type inactivation behavior, suggestive of the importance of charge at this site. Kinetic modeling suggests that the E352C and R289C inactivation phenotypes largely resulted from reductions in the rate constants for transitions from closed to inactivated states. The data indicate that specific residues within the S3-S4 and S5-P-loop linkers may play important roles in Kv2.1 U-type inactivation.

Frequent methamphetamine injection predicts emergency department utilization among street-involved youth

OBJECTIVES

Methamphetamine (MA) use has been associated with health problems that commonly present in the emergency department (ED). This study sought to determine whether frequent MA injection was a risk factor for ED utilization among street-involved youth.

STUDY DESIGN

Prospective cohort study.

METHODS

Data were derived from a street-involved youth cohort known as the 'At Risk Youth Study'. Behavioural data including MA use were linked to ED records at a major inner-city hospital. Kaplan-Meier and Cox proportional hazards methods were used to determine the risk factors for ED utilization.

RESULTS

Between September 2005 and January 2007, 427 eligible participants were enrolled, among whom the median age was 21 (interquartile range 19-23) years and 154 (36.1%) were female. Within 1 year, 163 (38.2%) visited the ED, resulting in an incidence density of 53.7 per 100 person-years. ED utilization was significantly higher among frequent (i.e. ≥daily) MA injectors (log-rank P = 0.004). In multivariate analysis, frequent MA injection was associated with an increased hazard of ED utilization (adjusted hazard ratio = 1.84, 95% confidence interval 1.04-3.25; P = 0.036).

CONCLUSIONS

Street-involved youth who frequently inject MA appear to be at increased risk of ED utilization. The integration of MA-specific addiction treatment services within emergency care settings for high-risk youth is recommended.

Structural diversity of neuritogenic substances and their application perspective

Small molecular weight substances are functional, as neurotrophic factors can be developed as therapeutic drugs to treat neurodegenerative disorder. Recently, a large number of natural and synthetic neuritogenic compounds have been discovered. These compounds have various structural features, including terpenoids, lipids, alkaloids, steroid glycosides, small molecular peptides, and so on. Some of them possess not only neurotrophic properties but also neuroprotective activities. The structure-activity relationships (SARs) and mechanism of action of some important compounds have been studied intensively. Increasing experimental evidence suggests that several of these compounds can be promising candidates for drug development.

Quantum control of the spin-orbit interaction using the Autler-Townes effect

We have demonstrated quantum control of the spin-orbit interaction based on the Autler-Townes (ac-Stark) effect in a molecular system using a cw optical field. We show that the enhancement of the spin-orbit interaction between a pair of weakly interacting singlet-triplet rovibrational levels, G (1)Π(g)(v=12,J=21,f)-1 (3)Σ(g)(-)(v=1,N=21,f), separated by 750 MHz in the lithium dimer, depends on the Rabi frequency (laser power) of the control laser. The increase in the spin-orbit interaction due to the control field is observed as a change in the spin character of the individual components of the perturbed pair.

Baifuzi reduces transient ischemic brain damage through an interaction with the STREX domain of BKCa channels

Stroke is a long-term disability and one of the leading causes of death. However, no successful therapeutic intervention is available for the majority of stroke patients. In this study, we explored a traditional Chinese medicine Baifuzi (Typhonium giganteum Engl.). We show, at first, that the ethanol extract of Baifuzi exerts neuroprotective effects against brain damage induced by transient global or focal cerebral ischemia in rats and mice. Second, the extract activated large-conductance Ca(2+)-activated K(+) channel (BK(Ca)) channels, and BK(Ca) channel blockade suppressed the neuroprotection of the extract, suggesting that the BK(Ca) is the molecular target of Baifuzi. Third, Baifuzi cerebroside (Baifuzi-CB), purified from its ethanol extract, activated BK(Ca) channels in a manner similar to that of the extract. Fourth, the stress axis hormone-regulated exon (STREX) domain of the BK(Ca) channel directly interacted with Baifuzi-CB, and its deletion suppressed channel activation by Baifuzi-CB. These results indicate that Baifuzi-CB activated the BK(Ca) channel through its direct interaction with the STREX domain of the channel and suggests that Baifuzi-CB merits exploration as a potential therapeutic agent for treating brain ischemia.

Contrast-enhanced ultrasonography for the detection and characterization of prostate cancer: correlation with microvessel density and Gleason score

AIM

To determine whether there is a correlation between the peak intensity of the lesion at contrast-enhanced ultrasonography and the microvessel density (MVD) and Gleason score in biopsy specimens of prostate cancer.

MATERIALS AND METHODS

Contrast-enhanced ultrasonography using cadence-contrast pulse sequence (CPS) technology was performed in 147 patients with suspected prostate cancer before biopsy. An auto-tracking contrast quantification (ACQ) software was used to analyse the peak intensity (PI) of the lesion. The Gleason score and MVD immunoreactivity were determined in the prostate biopsy specimens. Ultrasound findings were correlated with biopsy findings.

RESULTS

Prostate cancer was detected in 73 of 147 patients. The PI values of prostate cancer patients were significantly higher than those of non-malignant patients [9.81 (4.23) versus 5.69 (3.19) dB; p<0.01]. The mean (SD) PIs of prostate cancer lesions with a Gleason score of 6-9 were 7.08 (3.80), 8.65 (4.08), 9.76 (3.75), and 9.85 (4.13) dB, respectively. The PI value increased significantly with a higher Gleason score (p<0.01). The mean (SD) MVDs observed in prostate cancer lesions with a Gleason score of 6-9 were 52.50 (10.54), 56.85 (10.31), 59.91 (9.29), and 66.04 (11.82), respectively. There was a positive correlation between PI and MVD in prostate cancer, with a correlation coefficient of 0.617. No correlation was found between PI value and age, prostate specific antigen (PSA) or prostate specific antigen density (PSAD) level (p>0.05).

CONCLUSION

The PI obtained by CPS harmonic ultrasonography appears to be of value as an indicator of MVD and increases with a higher Gleason score. CPS harmonic ultrasonography could be promising as a useful imaging technique in the detection and characterization of prostate cancer.

LeERF-1, a novel AP2/ERF family gene within the B3 subcluster, is down-regulated by light signals in Lithospermum erythrorhizon

We previously showed that ethylene might be involved in the process of shikonin biosynthesis regulated by light signals. Here, we cloned a full-length cDNA of LeERF-1, a putative ethylene response factor gene, from Lithospermum erythrorhizon using the RACE (rapid amplification of cDNA ends) method. Phylogenetic analysis revealed that LeERF-1 was classified in the B3 subfamily, together with ERF1 and ORA59 of Arabidopsis. Heterologous expression of LeERF-1 in Arabidopsis showed that LeERF-1:eGFP fusion protein was precisely localised to the nucleus, implying that it might function as a transcription factor. Detailed expression analysis with real-time PCR showed that LeERF-1 was significantly down-regulated by white, blue and red light, although the inhibitory effect of red light was relatively weak compared to other light conditions. Tissue-specific expression analysis also indicated that LeERF-1 was dominantly expressed in the roots, which grow in soil in darkness. These patterns are all consistent with the effects of different light signals on regulating formation of shikonin and its derivatives, indicating that LeERF-1 might be a crucial positive regulator, like other B3 subfamily proteins (such as ORCA3 and ORA59), in regulating biosynthesis of secondary metabolites.