Midkine (MK) is a heparin‐binding growth factor or cytokine and forms a small protein family, the other member of which is pleiotrophin. MK enhances survival, migration, cytokine expression, ...differentiation and other activities of target cells. MK is involved in various physiological processes, such as development, reproduction and repair, and also plays important roles in the pathogenesis of inflammatory and malignant diseases. MK is largely composed of two domains, namely a more N‐terminally located N‐domain and a more C‐terminally located C‐domain. Both domains are basically composed of three antiparallel β‐sheets. In addition, there are short tails in the N‐terminal and C‐terminal sides and a hinge connecting the two domains. Several membrane proteins have been identified as MK receptors: receptor protein tyrosine phosphatase Z1 (PTPζ), low‐density lipoprotein receptor‐related protein, integrins, neuroglycan C, anaplastic lymphoma kinase and Notch‐2. Among them, the most established one is PTPζ. It is a transmembrane tyrosine phophatase with chondroitin sulfate, which is essential for high‐affinity binding with MK. PI3K and MAPK play important roles in the downstream signalling system of MK, while transcription factors affected by MK signalling include NF‐κB, Hes‐1 and STATs. Because of the involvement of MK in various physiological and pathological processes, MK itself as well as pharmaceuticals targeting MK and its signalling system are expected to be valuable for the treatment of numerous diseases.
Linked Articles
This article is part of a themed section on Midkine. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue‐4
Midkine (MK) and pleiotrophin (PTN) are low molecular weight proteins with closely related structures. They are mainly composed of two domains held by disulfide bridges, and there are three ...antiparallel β-sheets in each domain. MK and PTN promote the growth, survival, and migration of various cells, and play roles in neurogenesis and epithelial mesenchymal interactions during organogenesis. A chondroitin sulfate proteoglycan, protein-tyrosine phosphatase ζ (PTPζ), is a receptor for MK and PTN. The downstream signaling system includes ERK and P13 kinase. MK binds to the chondroitin sulfate portion of PTPζ with high affinity. Among the various chondroitin sulfate structures, the E unit which has 4, 6-disulfated N-acetylgalactosamine, provides the strongest binding site. The expression of MK and PTN is increased in various human tumors, making them promising as tumor markers and as targets for tumor therapy. MK and PTN expression also increases upon ischemic injury. MK enhances the migration of inflammatory cells, and is involved in neointima formation and renal injury following ischemia. MK is also interesting from the viewpoints of the treatment of neurodegenerative diseases, increasing the efficiency of in vitro development, and the prevention of HIV infection.
Background. Pruritus in haemodialysis patients is an intractable disease and substantially impairs their quality of life. Based on the results of our earlier clinical study, we hypothesized that the ...μ-(mu) opioid system is itch-inducible, whereas the κ (kappa) system is itch-suppressive. Methods. The efficacy and safety of nalfurafine hydrochloride (a novel κ-receptor agonist) were prospectively investigated by randomly (1:1:1) administering 5 or 2.5 μg of the drug or a placebo orally for 14 days using a double-blind design in 337 haemodialysis patients with itch that was resistant to currently available treatments, such as antihistamines. Results. The mean decrease in the visual analogue scale (VAS) from baseline, the study's primary endpoint, was significantly larger in the 5-μg nalfurafine hydrochloride group (n = 114) than in the placebo group (n = 111, P = 0.0002, one-sided test at 2.5% significance level). The decrease in the VAS in the 2.5-μg group (n = 112) was also significantly larger than that in the placebo group (P = 0.0001). The incidence of adverse drug reactions (ADRs) was 35.1% in the 5-μg group, 25.0% in the 2.5-μg group and 16.2% in the placebo group. Moderate to severe ADRs were observed in 10 of the 226 patients. The most common ADR was insomnia (sleep disturbance), seen in 24 of the 226 nalfurafine patients. Conclusions. This Phase III, randomized, double-blind, placebo-controlled, parallel-group, prospective study based on VAS evaluations clearly showed that orally taken nalfurafine hydrochloride effectively reduced itches that were otherwise refractory to currently available treatments in maintenance haemodialysis patients, with few significant ADRs. This novel drug was officially approved for clinical use in January 2009 by the Ministry of Health, Labour and Welfare of Japan.
Metastasis is a critical factor contributing to poor prognosis in cancer, but the underlying mechanisms of metastasis are still poorly understood. We established a highly metastatic cell subline ...(HOC313-LM) derived from an oral squamous cell carcinoma cell line (HOC313) for uncovering the mechanisms of metastasis, and identified deoxyhypusine synthase (DHPS) as a metastasis-associated gene within the specific amplification at 19p13.2-p13.13 in HOC313-LM. DHPS-mediated hypusine-modification of eukaryotic translation factor 5A facilitated the translation of RhoA, resulting in the activation of the RhoA signaling pathway and leading to not only increased cell motility, invasion and metastasis of cancer cells in vitro, but also increased tumor growth in vivo. Moreover, the use of N1-Guanyl-1,7-diaminoheptane, a DHPS inhibitor, resulted in a significant decrease in tumor formation in vivo. In patients with esophageal squamous cell carcinoma (ESCC), overexpression of DHPS in ESCC tumors was significantly associated with worse recurrence-free survival, and correlated with distant metastasis. The elucidation of these molecular mechanisms within the hypusine cascade suggests opportunities for novel therapeutic targets in SCC.
Epithelial-mesenchymal transition (EMT) has a major role in cancer progression, as well as normal organ development and human pathology such as organ fibrosis and wound healing. Here, we performed a ...gene expression array specialized in EMT of colorectal cancer (CRC). From a comprehensive gene expression analysis using epithelial- and mesenchymal-like CRC cell lines, and following the ontology (GO) analysis, SIX1 gene was identified to be an EMT-related gene in CRC. Using SW480 cells stably transfected with a SIX1 expression construct and their control counterparts, we demonstrated that SIX1 overexpression represses CDH1 expression and promotes EMT in CRC. SIX1-induced CDH1 repression and EMT in CRC cells were correlated at least in part with posttranscriptional ZEB1 activation and miR-200-family transcriptional repression. In primary tumors of CRC, in accord with the functional findings, aberrant expression of SIX1 in cancer cells was observed at the disruption of the basement membrane and at the tumor invasive front, where tumor cells underwent EMT in vivo. Taken together, SIX1 overexpression is suggested to occur in carcinogenesis, and contribute to repression of CDH1 expression and promotion of EMT partly through repression of miR-200-family expression and activation of ZEB1 in CRC.
Measuring accurate displacement distributions for large-scale structures is an important issue and a very challenging task. Recently, a simple and accurate phase measurement technique called sampling ...moiré method Exp Mech 50–4:501–508, (
2010
) has been developed for small-displacement distribution measurements. In this method, the phase distribution of moiré fringes can be analyzed from a single grating image by simultaneously performing down-sampling image processing and intensity-interpolation to generate multiple phase-shifted moiré fringe images. In addition, the phase of the original grating can also be obtained from the phase of the moiré fringe by adding the phase of the sampling grating. In this study, the measurement accuracy of the sampling moiré method was analyzed through computer simulations and a displacement measurement experiment. Four factors of the sampling moiré method were investigated, including the sampling pitch, the order of the intensity-interpolation, random noise, and the form of grating. The results show that determining the optimal sampling pitch is an important factor for obtaining better results but it is not critical. In addition, a practical application of the sampling moiré method is presented that involves a deflection measurement on a 10-meter-long crane. The experimental results demonstrate that submillimeter deflections of the crane can be successfully detected.
Abrasive water jet processes of glass are presented for crack-free machining of micro grooves and fluid polishing of micro channels with CFD analysis. In machining of the micro grooves, the abrasive ...is supplied to flow through intended machining area using the tapered masks. Stagnation under the jet and the horizontal flow on the machining area are controlled to generate crack-free surfaces by the mask shape. The same effect can be applied to polishing of the micro channels pre-machined by milling. Stagnation controlled by the inner wall of the channel changes the flow direction while keeping high fluid velocities.
Aim
To investigate the proliferation and mineralization of a human cementoblast cell line under alkaline conditions.
Methodology
A human cementoblast cell line was cultured in alkaline media with ...several pHs (pH 7.6, 8.0 and 8.4) without CO2. Cell numbers, phospho‐p44/42 expression, alkaline phosphatase (ALP) activity and mineralization were evaluated. The significance of differences between groups was assessed using two‐way analysis of variance 15 (ANOVA) followed by Bonferroni's multiple comparison test (α = 0.01).
Results
Cell numbers increased in a time‐dependent manner in the high pH medium groups. Western blot analysis revealed the upregulated expression of phospho‐p44/42 under alkaline conditions. ALP activity was also increased at pH 8.0 and 8.4. Alizarin red staining revealed increased mineralization in the high pH medium groups. The incorporation of the transient receptor potential ankyrin subfamily member 1 (TRPA1) antagonist HC030031 markedly negated the effect on proliferation and mineralization.
Conclusions
Extracellular alkaline conditions promoted the proliferation and mineralization of human cementoblasts in vitro via TRPA1.
Aim
To examine DNA methylation of GJA1, BMP2 and BMP4 in human cementoblasts (HCEM) induced by lipopolysaccharide (LPS).
Methodology
HCEM were cultured in osteoinduction medium. After 24 h, ...Escherichia coli LPS (1 μg/mL) was added to the medium, which was changed every 2–3 days. Untreated samples were used as controls. Messenger RNA was extracted after 4 weeks, and quantitative real‐time polymerase chain reaction (qRT‐PCR) for GJA1, BMP2, BMP4 and DNMT1 was performed. Genomic DNA was extracted after 4 weeks, and quantitative methylation‐specific polymerase chain reaction was carried out for GJA1, BMP2 and BMP4. To detect mineralization, alizarin red and alkaline phosphatase staining were performed. The cells were also treated with the DNA methyltransferase inhibitor 5‐Aza‐2'‐deoxycytidine (5Aza) and examined. The significance of differences amongst groups was assessed using a two‐way analysis of variance (ANOVA) followed by Bonferroni’s multiple comparison test with P < 0.05 being significant.
Results
Decreased expression of mRNA was seen in GJA1, BMP2 and BMP4 after 4 weeks (P < 0.05). DNA hypermethylation was detected in GJA1, BMP2 and BMP4 (P < 0.05). Alizarin red staining and alkaline phosphatase staining revealed decreased mineralization levels in HCEM stimulated with LPS. 5Aza abolished the effects of DNA methylation in HCEM stimulated with LPS.
Conclusions
These results suggest that long‐term LPS stimulation induces DNA methylation of GJA1, BMP2 and BMP4 in HCEM.
Enhancer of zeste homolog 2 (EZH2) enhances tumorigenesis and is commonly overexpressed in several types of cancer. To investigate the anticancer effects of EZH2 inhibitors, microRNA (miRNA) ...expression profiles were examined in gastric and liver cancer cells treated with suberoylanilide hydroxamic acid (SAHA) and 3-deazaneplanocin A (DZNep). We confirmed that SAHA and DZNep suppressed EZH2 expression in AGS and HepG2 cells and inhibited their proliferation. The results of microarray analyses demonstrated that miR-1246 was commonly upregulated in cancer cells by treatment with SAHA and DZNep. MiR-302a and miR-4448 were markedly upregulated by treatment with SAHA and DZNep, respectively. DYRK1A, CDK2, BMI-1 and Girdin, which are targets of miR-1246, miR-302a and miR-4448, were suppressed by treatment with SAHA and DZNep, leading to apoptosis, cell cycle arrest and reduced migration of AGS and HepG2 cells. ChIP assay revealed that SAHA and DZNep inhibited the binding of EZH2 to the promoter regions of miR-1246, miR-302a and miR-4448. These findings suggest that EZH2 inhibitors such as SAHA and DZNep exert multiple anticancer effects through activation of tumor-suppressor miRNAs.
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