Takada-Watanabe A.,Chiba University |
Yokote K.,Chiba University |
Takemoto M.,Chiba University |
Fujimoto M.,Chiba University |
And 5 more authors.
Geriatrics and Gerontology International | Year: 2012
Werner syndrome (WS) is an autosomal recessive progeroid disorder caused by mutations in the WRN DNA helicase. It is characterized by the graying and loss of hair, juvenile cataracts, sclerosis and ulceration of skin, insulin-resistant diabetes mellitus, dyslipidemia, abdominal adiposity, osteoporosis, atherosclerosis, and malignant neoplasm. Patients are usually diagnosed in their 30s or 40s, but the early pathophysiology of the syndrome is still not fully understood. Here we report a 29-year-old female patient who displayed cataracts, hair graying, and tendinous calcinosis. Her parents were first cousins. Interestingly, the patient lacked the metabolic signs typical for WS, including glucose intolerance, dyslipidemia, and visceral fat accumulation. A hyperinsulinemic response at 30min was observed in an oral glucose tolerance test. Mutational analysis for the WRN gene revealed a homozygous nucleotide substitution 3190C>T in exon 24, resulting in a protein product with replacement of an arginine residue at position 573 by termination codon (Arg987Ter). The mutated WRN protein was unable to translocate into the nucleus in an in vitro cell assay. A WS patient with an Arg987Ter mutation has been previously reported in Switzerland, the present case is the first to be identified in Asia. This case demonstrates the early clinical features of WS and suggests that metabolic abnormality, including insulin resistance, is not an essential component of WS at disease onset. Moreover, a follow-up study of such case would be useful to understand how the various clinical symptoms in WS develop and progress over the years. © 2011 Japan Geriatrics Society.
Arai A.,Shiga University of Medical Science |
Arai A.,Kyoto Prefectural University of Medicine |
Chano T.,Shiga University of Medical Science |
Futami K.,GeneCare Research Institute |
And 8 more authors.
Cancer Research | Year: 2011
RECQL1 and WRN proteins are RecQ DNA helicases that participate in suppression of DNA hyper-recombination and repair. In this study, we report evidence supporting their candidacy as cancer therapeutic targets. In hypopharyngeal carcinomas, which have the worst prognosis among head and neck squamous cell carcinomas (HNSCC) that are rapidly rising in incidence, we found that RECQL1 and WRN proteins are highly expressed and that siRNA-mediated silencing of either gene suppressed carcinoma cell growth in vitro. Similarly, siRNA administration in a murine xenograft model of hypopharyngeal carcinoma markedly inhibited tumor growth. Moreover, combining either siRNA with cis-platinum (II) diammine dichloride significantly augmented the in vivo anticancer effects of this drug that is used commonly in HNSCC treatment. Notably, we observed no recurrence of some tumors following siRNA treatment in this model. Our findings offer a preclinical proof of concept for RECQL1 and WRN proteins as novel therapeutic targets to treat aggressive HNSCC and perhaps other cancers. ©2011 AACR.
Kabir M.E.,Niigata University of Pharmacy and Applied Life Sciences |
Kabir M.E.,Case Western Reserve University |
Krishnaswamy S.,Niigata University of Pharmacy and Applied Life Sciences |
Krishnaswamy S.,New York University |
And 5 more authors.
Microbiology and Immunology | Year: 2014
Immunoassay designs rely on the great specificity of antibodies and a suitable marker that facilitates generation of a quantitative signal. Currently, there is no reliable method for measuring the titers of an anti-idiotypic antibody. Our initial attempt to measure titers of mouse anti-idiotypic antibody after idiotypic vaccination with HM-1 killer toxin neutralizing monoclonal antibody (nmAb-KT) failed. Because the injected antigen, nmAb-KT, is a mouse IgG, using a commercial antibody to measure the antibody titer always gave a false positive signal against control mouse serum antibody in parallel with the antigen-treated immunized serum antibodies. To get a reliable and clearly differentiable signal by ELISA, idiotypic antigen was labeled with HRP and HRP-conjugated-nmAb-KT used to measure the antibody titers in the antigen-treated mice. Compared with control mice, signals were found in high anti-nmAb-KT IgG responses in test mice; however, untreated control mice had a significant amount of purified non-specific IgG. This method is amenable to long read lengths and will likely enable anti-idiotypic antibody titer measurement in a more specific and cost effective way without requiring commercial antibody. © 2014 The Societies and Wiley Publishing Asia Pty Ltd.
De S.,National Institute of Immunology |
Kumari J.,National Institute of Immunology |
Mudgal R.,National Institute of Immunology |
Modi P.,National Institute of Immunology |
And 7 more authors.
Journal of Cell Science | Year: 2012
Mutations in RECQL4 helicase are associated with Rothmund-Thomson syndrome (RTS). A subset of RTS patients is predisposed to cancer and is sensitive to DNA damaging agents. The enhanced sensitivity of cells from RTS patients correlates with the accumulation of transcriptionally active nuclear p53. We found that in untreated normal human cells these two nuclear proteins, p53 and RECQL4, instead colocalize in the mitochondrial nucleoids. RECQL4 accumulates in mitochondria in all phases of the cell cycle except S phase and physically interacts with p53 only in the absence of DNA damage. p53-RECQL4 binding leads to the masking of the nuclear localization signal of p53. The N-terminal 84 amino acids of RECQL4 contain a mitochondrial localization signal, which causes the localization of RECQL4-p53 complex to the mitochondria. RECQL4-p53 interaction is disrupted after stress, allowing p53 translocation to the nucleus. In untreated normal cells RECQL4 optimizes de novo replication of mtDNA, which is consequently decreased in fibroblasts from RTS patients. Wild-type RECQL4-complemented RTS cells show relocalization of both RECQL4 and p53 to the mitochondria, loss of p53 activation, restoration of de novo mtDNA replication and resistance to different types of DNA damage. In cells expressing D84 RECQL4, which cannot translocate to mitochondria, all the above functions are compromised. The recruitment of p53 to the sites of de novo mtDNA replication is also regulated by RECQL4. Thus these findings elucidate the mechanism by which p53 is regulated by RECQL4 in unstressed normal cells and also delineates the mitochondrial functions of the helicase. © 2012. Published by The Company of Biologists Ltd.