Cancer stem cells have been proposed to be responsible for tumorigenesis and recurrence in various neoplastic diseases, including multiple myeloma (MM). We have previously reported that MM cells ...specifically express HLA class I at high levels and that single-chain Fv diabody against this molecule markedly induces MM cell death. Here we investigated the effect of a new diabody (C3B3) on cancer stem cell-like side population (SP) cells. SP fraction of MM cells highly expressed ABCG2 and exhibited resistance to chemotherapeutic agents; however, C3B3 induced cytotoxicity in both SP cells and main population (MP) cells to a similar extent. Moreover, C3B3 suppressed colony formation and tumorigenesis of SP cells in vitro and in vivo. Crosslinking of HLA class I by C3B3 mediated disruption of lipid rafts and actin aggregation, which led to inhibition of gene expression of β-catenin and pluripotency-associated transcription factors such as Sox2, Oct3/4 and Nanog. Conversely, knockdown of Sox2 and Oct3/4 mRNA reduced the proportion of SP cells, suggesting that these factors are essential in maintenance of SP fraction in MM cells. Thus, our findings reveal that immunotherapeutic approach by engineered antibodies can overcome drug resistance, and provide a new basis for development of cancer stem cell-targeted therapy.
The pH-dependent antigen binding antibody, termed a recycling antibody, has recently been reported as an attractive type of second-generation engineered therapeutic antibody. A recycling antibody can ...dissociate antigen in the acidic endosome, and thus bind to its antigen multiple times. As a consequence, a recycling antibody can neutralize large amounts of antigen in plasma. Because this approach relies on histidine residues to achieve pH-dependent antigen binding, which could limit the epitopes that can be targeted and affect the rate of antigen dissociation in the endosome, we explored an alternative approach for generating recycling antibodies. Since calcium ion concentration is known to be lower in endosome than in plasma, we hypothesized that an antibody with antigen-binding properties that are calcium-dependent could be used as recycling antibody. Here, we report a novel anti-interleukin-6 receptor (IL-6R) antibody, identified from a phage library that binds to IL-6R only in the presence of a calcium ion. Thermal dynamics and a crystal structure study revealed that the calcium ion binds to the heavy chain CDR3 region (HCDR3), which changes and possibly stabilizes the structure of HCDR3 to make it bind to antigen calcium dependently (PDB 5AZE). In vitro and in vivo studies confirmed that this calcium-dependent antigen-binding antibody can dissociate its antigen in the endosome and accelerate antigen clearance from plasma, making it a novel approach for generating recycling antibody.
We have developed a new monitoring system to detect an unusual event in the superconducting coils without direct contact on the coils, using Poynting’s vector method. In this system, the potential ...leads and pickup coils are set around the superconducting coils to measure local electric and magnetic fields, respectively. By measuring the sets of magnetic and electric fields, the Poynting’s vectors around the coil can be obtained. An unusual event in the coil can be detected as the result of the change of the Poynting’s vector. This system has no risk of the voltage breakdown which may happen with the balance voltage method, because there is no need of direct contacts on the coil windings. In a previous paper, we have demonstrated that our system can detect the normal transitions in the Bi-2223 coil without direct contact on the coil windings by using a small test system. For our system to be applied to practical devices, it is necessary for the early detection of an unusual event in the coils to be able to detect local normal transitions in the coils. The signal voltages of the small sensors to measure local magnetic and electric fields are small. Although the increase in signals of the pickup coils is attained easily by an increase in the number of turns of the pickup coils, an increase in the signals of the potential lead is not easily attained. In this paper, a new method to amplify the signal of local electric fields around the coil is proposed. The validity of the method has been confirmed by measuring local electric fields around the Bi-2223 coil.
Peutz-Jeghers syndrome (PJS) is a dominantly inherited human disorder characterized by gastrointestinal hamartomatous polyposis and mucocutaneous melanin pigmentation. LKB1 (STK11) serine/threonine ...kinase is the product of the causative gene of PJS, which has been mapped to chromosome 19p13.3. However, several studies have produced results that are not consistent with a link between LKB1 gene mutation and PJS. We constructed a knockout gene mutation of Lkb1 to determine whether it is the causative gene of PJS and to examine the biological role of the Lkb1 gene. Lkb1-/-mice died in utero between 8.5 and 9.5 days postcoitum. At 9.0 days postcoitum, Lkb1-/-embryos were generally smaller than their age-matched littermates, showed developmental retardation, and did not undergo embryonic turning. Multiple gastric adenomatous polyps were observed in 10- to 14-month-old Lkb1+/-mice. Our results indicate that functional Lkb1 is required for normal embryogenesis and that it is related to tumor development. The Lkb1+/-mouse is suitable for studying molecular mechanism underlying the development of inherited gastric tumors in PJS.
The purpose of this study was to clarify whether higher doses of steroids improve the prognosis of idiopathic sensorineural hearing loss (ISHL) and the suitable dose of steroid hormone.
The study was ...a retrospective statistical analysis.
This study was performed at the Department of Otolaryngology, Head Neck Surgery, Kumamoto University School of Medicine.
Two hundred fifty patients with ISHL were analyzed in this study. They were divided into two groups: those receiving less than a specified daily dose of steroid and those receiving a daily dose greater than or equal to the specified dose.
The patients received systemic steroid therapy combined with adenosine triphosphate, vitamins, diuretics, vasodilators, hyperbaric oxygen therapy, stellate ganglion block, or volume expander.
The correlation between the initial dose of steroid hormone and the improvement rate was analyzed.
Spearman's correlation coefficients and partial correlation coefficients between the initial dose and the prognosis were all significantly negative. On the other hand, the correlations between the initial dose and the prognosis were positive in the group receiving <30 mg/day, whereas they were negative in the group receiving > or =30 mg/day, although these correlations were not significant.
The general use of steroid hormone to treat ISHL is not recommended. Furthermore, if steroid hormone is used for treatment, the use of <30 mg/day of prednisolone is preferable.
Amorphous rare earth (Cd, Tb and Dy)-transition metal (Fe, Co and FeCo alloy) thin films with an artificially layered structure have been investigated. The films were deposited in an alternating ...multi-layer structure by the multi-source DC-sputtering method. Films with a repeat unit composed of a monatomic layer of RE and a few atomic layers of TM show excellent magnetic properties when considered as magnetooptical recording media, such as a large magnetization and perpendicular magnetic anisotropy. RE-FeCo and RE-CoFe films used in magnetooptical recording showed carrier-to-noise ratios higher than 52 db, and Dy-FeCo films showed a high carrier-to-noise ratio over a wide frequency range that extended from 57 dB at 1 MHz to 38 db at 10 MHz.
We previously reported that inflammatory arthropathy resembling rheumatoid arthritis (RA) develops among transgenic mice carrying the long terminal repeat (LTR)-env-pX-LTR region of human T cell ...leukemia virus type I (LTR-pX-Tg mice). Because four genes are encoded in this region, we produced transgenic mice that only express the tax gene to examine its role in the development of arthritis. Transgenic mice were produced by constructing DNAs that express the tax gene alone under the control of either its own LTR or CD4 enhancer/promoter and by microinjecting them into C3H/HeN-fertilized ova. We produced seven transgenic mice carrying the LTR-tax gene and nine mice carrying the CD4-tax and found that one of the LTR-tax-Tg mice and five of CD4-tax-Tg mice developed RA-like inflammatory arthropathy similar to LTR-pX-Tg mice, indicating that the tax gene is arthritogenic. On the other hand, the other two LTR-tax-Tg mice had ankylotic changes caused by new bone formation without inflammation. In these ankylotic mice, tax mRNA, inflammatory cytokine mRNA, and autoantibody levels except for TGF-beta1 level were lower than those in LTR-pX- or CD4-tax-Tg mice. These results show that Tax is responsible for the development of inflammatory arthropathy resembling RA and that this protein also causes ankylotic arthropathy.
PDF
