Biomedical subjects

Shingo Ichimiya

Publications and source records attributed to Shingo Ichimiya.

At least 19 recordsLinked to original sources

PubMed2007

Mapping of susceptibility and protective loci for acute GVHD in unrelated HLA-matched bone marrow transplantation donors and recipients using 155 microsatellite markers on chromosome 22.

Despite matching donors and recipients for the human leukocyte antigens (HLAs) expressed by the major histocompatibility genomic region of the short arm of chromosome 6, several recipients still develop acute graft-versus-host disease (aGVHD) after bone marrow transplantation (BMT). This is possibly due to non-HLA gene polymorphisms, such as minor histocompatibility antigens (mHas) and genes coding for cytokines. However, a detailed genetic background for aGVHD has not yet been established. To find novel susceptibility and/or protective loci for aGVHD, a whole genome-wide association study of donors and recipients needs to be performed. As the first step to such a study, we retrospectively analyzed polymorphisms of 155 microsatellite markers spread across the long arm of chromosome 22 in 70 pairs of HLA-matched unrelated BMT donors and recipients. We performed individual typing and then compared the markers' allele frequencies (1) between all the aGVHD (grades III and IV GVHD) and GVHD-free (grade 0 GVHD) groups in donors and recipients and (2) between the aGVHD and aGVHD-free groups in donor/recipient pairs that were matched and mismatched for the microsatellite marker's allele. Screening of the microsatellite markers revealed five loci with a significant difference between the aGVHD and GVHD-free groups and revealed eight loci on chromosome 22, where the microsatellite allele mismatched markers were associated with aGVHD. This screening analysis suggests that several aGVHD-associated susceptible and protective loci exist on chromosome 22, which may encompass novel gene regions that need to be elucidated for their role in aGVHD.

Acute Disease↗

PubMed2006

Cellular networks of human thymic medullary stromas coordinated by p53-related transcription factors.

The final elimination step of self-reactive T cells occurs in the medulla of the thymus where a complex framework provided by stromal cells supports an optimal milieu for their selection. Here we present evidence that tight junctions (TJs) widely join medullary stromal cells of the human thymus. Occludin (OCLN) and claudin-1 (CLDN-1) of TJ-associated molecules were dominantly expressed in medullary thymic epithelial cells (mTECs), and CLDN-4 and CLDN-7 were also localized in some mTECs near Hassall's corpuscles. Interestingly, p53-like transcription factors were found to upregulate OCLN and CLDN-1 in human TEC lines, as recently suggested in the regulation of mTEC function. Furthermore, dendritic cells (DCs) of the medulla, with a major role for selection of thymocytes, expressed CLDN-1 and OCLN as well, implying that the interposition of DCs within the mTEC scaffold is also helped by TJs. Analysis of freeze-fracture replicas of the thymus revealed TJ strand structures in the vicinity of gap junction plaques through which small molecules might move, as implied by dye-transfer analysis of a medullary cell line. Thus, it is thought that p53-like molecules regulate TJ-associated interactions of medullary stromal cells and that this mechanism might be associated with an intercellular communication network, probably for preserving the medullary niches.

Cell Communication↗

PubMed2005

Clinical significance of vascular endothelial growth factor-C and vascular endothelial growth factor receptor 3 in patients with T1 lung adenocarcinoma.

BACKGROUND: Vascular endothelial growth factor-C (VEGF-C) plays an important role in lymphangiogenesis and activates VEGF receptor-3 (VEGFR-3). Lymphatic spread is an important prognostic factor in patients with lung adenocarcinoma. The aim of the current study was to determine whether the expression of VEGF-C and VEGFR-3 correlates with clinicopathologic factors and prognosis in patients with TNM classification T1 lung adenocarcinoma. METHODS: The authors conducted a retrospective review of 129 consecutive patients who underwent complete resection for T1 lung adenocarcinoma. Immunohistochemical staining for VEGF-C, VEGF, VEGFR-3, CD34 (microvessels), tryptase (mast cells), and CD68 (macrophages) was performed to statistically analyze clinicopathologic implications of VEGF-C and VEGFR-3 status. RESULTS: Of 129 patients with T1 lung adenocarcinoma, 56 (43.3%) patients were positive for tumor-cell VEGF-C and 73 (56.6%) and 69 (53.5%) patients were positive for tumor-cell and endothelial-cell VEGFR-3, respectively. Patients with positive staining for tumor-cell VEGF-C showed significantly less favorable survival rates than patients with negative staining (P = 0.031). The survival rates of patients with positive staining for tumor-cell and endothelial-cell VEGFR-3 were significantly lower than those with negative staining (P = 0.0034 and P = 0.0020, respectively). Patients with positive staining for both tumor-cell VEGF-C and endothelial-cell VEGFR-3 exhibited the most unfavorable prognoses. Multivariate analysis demonstrated that coexpression of tumor-cell VEGF-C and endothelial-cell VEGFR-3 was an independent negative prognostic factor (P = 0.0129) as well as N factor (P = 0.0020). CONCLUSIONS: VEGF-C and VEGFR-3 status may be indicative of survival rates for patients with T1 lung adenocarcinoma.

Adenocarcinoma↗

PubMed2005

Effects of inhaled FK 506 on the suppression of acute rejection after lung transplantation: use of a rat orthotopic lung transplantation model.

BACKGROUND: FK 506 inhalant was recently developed for localized administration. We investigated its effects on acute lung allograft rejection and compared its efficacy with that of intramuscular administration of FK 506. METHODS: Rats (n = 123) with orthotopic left lung transplantation were divided into 9 groups. Six groups inhaled FK 506 (5 puffs, 10 puffs or 20 puffs per day), or were given intramuscular administration of FK 506 (0.05, 0.1 or 1.0 mg/kg/day). The other groups included rats receiving an isograft, rats with an untreated allograft, and a placebo group. All groups (n = 6 each) were monitored for 14 days post-operatively as an end-point and graft survival time was determined. The remaining animals were killed 4 days after transplantation. The histologic grade of rejection was determined for all groups (n = 6 each). With both (n = 3 each) inhalation therapy and intramuscular administration of FK 506, which showed similar degrees of effectiveness, both blood FK 506 concentration and cytokine expression in the graft and spleen were evaluated. RESULTS: FK 506 inhalation therapy extended allograft survival time and reduced histologic rejection on Day 4 in all groups. Graft survival time and histologic rejection scores at a dose of 10 puffs/day were comparable to those with 0.1 mg/kg/day of intramuscular FK 506. Trough concentrations of FK 506 in blood were detectable with 0.1 mg/kg/day of intramuscular FK 506, but not with 10 puffs/day. The messenger RNA expression levels of interferon-gamma in the lung allograft was suppressed significantly at a dose of 10 puffs/day. CONCLUSIONS: FK 506 inhalant enhances acute lung allograft survival with lower blood concentrations than when using comparable intramuscular administration.

Administration, Inhalation↗

PubMed2005

Napsin A is useful to distinguish primary lung adenocarcinoma from adenocarcinomas of other organs.

The aim of the present study was to compare the usefulness of the peripheral airway cell markers, naspin A and surfactant protein A (SP-A), for distinguishing primary lung adenocarcinoma from adenocarcinomas of other organs in various clinical conditions. Immunohistochemical expression of napsin A and SP-A was analyzed at primary sites of 120 lung carcinomas and 40 adenocarcinomas of other organs, at lung metastatic sites of 32 adenocarcinomas of other organs, and in metastatic lymph nodes of 21 lung adenocarcinomas and 45 adenocarcinomas of other organs. Napsin A and SP-A expressions were compared between primary and recurrent sites in 8 lung adenocarcinomas. Napsin A and SP-A expressions were noted in 84.3% and 53.0% of primary sites of 83 lung adenocarcinomas, respectively, but neither napsin A nor SP-A was expressed at primary sites of other histological types of lung carcinomas or at primary or metastatic sites of adenocarcinomas of other organs. In lung adenocarcinomas, napsin A and SP-A were expressed in metastatic lymph nodes in 81.0% and 19.0%, respectively, and at recurrent sites in 87.5% and 37.5%, respectively. Napsin A is superior to SP-A for distinguishing primary lung adenocarcinoma from adenocarcinomas of other organs at primary, metastatic, and recurrent sites.

Adenocarcinoma↗

PubMed2005

A calcium binding protein, S100A4, mediates T cell dependent cytotoxicity as a transformation-associated antigen.

The nature of the target molecule of TCR gamma delta T cell-mediated lysis remains to be determined. As we previously reported, #067 monoclonal antibody (mAb) recognizes one of the transformation-associated antigens, designated as #067 antigen. This antigen is expressed on the cell surface of rat fibrosarcoma W31 cells, which are established by transformation of fetal fibroblastic WFB cells with H-ras oncogene. It has been suggested that the #067 antigen is a target molecule for TCR gamma delta T cells since #067 mAb inhibited TCR gamma delta T cell-mediated lysis against #067 positive cells. In this study we attempted to identify the protein sequence of the #067 antigen. By using molecular cloning techniques, we demonstrated that a calcium binding protein, S100A4, was possibly one and the same molecule as the #067 antigen. It was shown that the expression of S100A4 was higher in W31 cells than in WFB cells at transcription and protein level. Flow cytometry and immunocytochemical studies showed that #067 antigen partially co-localized with S100A4 on the cell surface as well as the cytoplasm of W31 cells. Moreover, rabbit anti-S100A4 polyclonal antibodies (pAb) inhibited TCR gamma delta T cell-mediated lysis against #067 positive cells. Our results indicated that S100A4 may play a role as a possible target molecule for TCR gamma delta T cell-mediated lysis although how S100A4 is involved in TCR gamma delta T cell-mediated lysis remains to be determined.

Animals↗

PubMed2005

HLA-DR- and CD11c-positive dendritic cells penetrate beyond well-developed epithelial tight junctions in human nasal mucosa of allergic rhinitis.

The epithelial barrier of the upper respiratory tract plays a crucial role in host defense. In this study, to elucidate whether there is antigen monitoring by dendritic cells (DCs) beyond the epithelial tight-junction barrier in allergic rhinitis, we investigated the expression and function of tight junctions and characterized DCs in the epithelium of nasal mucosa from patients with allergic rhinitis. In reverse transcription-polymerase chain reaction, mRNAs of tight-junction proteins occludin, JAM-1, ZO-1, and claudin-1, -4, -7, -8, -12, -13, and -14 were detected in the nasal mucosa. Occludin, JAM-1, and ZO-1 were colocalized in the uppermost layer in the pseudostratified epithelium of the nasal mucosa, whereas claudin-1, -4, and -7 were found throughout the epithelium. In freeze-fracture replicas of the nasal mucosa, continuous tight-junction strands formed well-developed networks. Epithelial barrier function measured by a dye tracer was well maintained in occludin-positive tight junctions in the epithelium of the nasal mucosa. HLA-DR- and CD11c-positive DCs expressed claudin-1 and penetrated beyond occludin in the epithelium of the nasal mucosa with, but not without, allergic rhinitis. These results indicate that DCs may easily access antigens beyond epithelial tight junctions in the human nasal mucosa of allergic rhinitis.

Adult↗

PubMed2004

Crisscross CTL induction by SYT-SSX junction peptide and its HLA-A*2402 anchor substitute.

To investigate the effects of anchor substitutions in SYT-SSX junction peptide, an HLA-A24 anchor residue (position 9) of the SYT-SSX B peptide (GYDQIMPKK) was substituted to more favorable residues according to the HLA-A24-binding motif. Among four substitutes constructed, a substitute with isoleucine (termed K9I peptide) most apparently enhanced the affinity for HLA-A24 molecule. Subsequent in vitro CTL induction analysis using PBMCs of 15 HLA-A24(+) synovial sarcoma patients revealed that the original B peptide allowed to induce synovial sarcoma-specific CTLs from 7 patients (47%), whereas such CTLs were inducible from 12 patients (80%) with K9I peptide. Moreover, the extent of cytotoxicity against HLA-A24(+) synovial sarcoma cell lines was higher in K9I peptide-induced CTLs than B peptide-induced CTLs. Influence of anchor substitution on peptide/TCR interaction was evaluated by cytotoxicity assays against autologous cells and tetramer analysis. CTLs induced from a synovial sarcoma patient using K9I peptide did not lyse autologous PHA blasts or EBV-infected B cells. In vitro stimulations of PBMCs from 5 HLA-A24(+) synovial sarcoma patients with K9I peptide increased the frequency of T cells reacting with both HLA-A24/K9I peptide tetramer and HLA-A24/B peptide tetramer. In contrast, the frequency of T cells reacting with HLA/HIV-derived peptide tetramer remained low. These findings support the validity in design of anchor residue substitution in SYT-SSX fusion gene-derived peptide, and provide a potential clue to the current stagnation in vaccination trials of fusion gene-derived natural junction peptides.

Amino Acid Substitution↗

PubMed2004

Expression profiles and functional implications of p53-like transcription factors in thymic epithelial cell subtypes.

In this study, we investigated the localization and functional significance of p53 tumor suppressor-like molecules, p63 and p73, in human thymic epithelial cells (TECs). Immunohistochemical studies showed particular distribution profiles of p63 and p73 in thymic epithelium, in which cortical TECs preferentially expressed p63 in their nuclei whereas subcapsular and medullary TECs expressed both p63 and p73 in their nuclei. The wide distribution of p63 in TECs was further suggested by studies using TECs of primary culture. In vitro studies using two human TEC lines demonstrated that p63 was capable of up-regulating intercellular adhesion molecule-1 (ICAM-1) and enhancing the production of IL-6 and IL-8. Moreover, in vitro studies also indicated that p73, but not p63, had the capacity to induce granulocyte macrophage colony stimulating factor (GM-CSF) and granulocyte colony stimulating factor (G-CSF) in the TEC lines. These findings suggest that p63 would regulate the cell adhesive property through ICAM-1/LFA-1 interaction and the production of IL-6 and IL-8, probably in all TEC subtypes. p73 in subcapslar and medullary TECs was suggested to play a role in the regulation of the production of GM-CSF and G-CSF, which might stimulate other stromal cells such as dendritic cells, macrophages and endothelial cells around these regions.

Cell Line↗

PubMed2004

Inhibition of MAP kinase activity moderates changes in expression and function of Cx32 but not claudin-1 during DNA synthesis in primary cultures of rat hepatocytes.

The signal transduction pathways and activation of the MAP kinase or PI3 kinase signaling cascade regulate a variety of cellular processes, including proliferation and differentiation in hepatocytes. To elucidate the mechanisms of signal transmission required for the regulation of gap and tight junctions during DNA synthesis in rat hepatocytes, we determined changes of expression and function of gap and tight junctions of cells grown in primary culture, using inhibitors of signaling pathways for MAP kinase (PD98059) and PI3 kinase (LY294002). During the stimulation of DNA synthesis induced by epidermal growth factor (EGF), immunoreactivity and mRNAs of gap junction protein Cx32 and of tight junction protein claudin-1 markedly decreased with reduction of gap junctional intercellular communication (GJIC) and the fence function of tight junctions. In Western blots, whole-cell lysate of claudin-1 protein decreased and phosphorylated Cx32 protein in the insoluble fraction of Triton X-100 increased during the stimulation of DNA synthesis. During reinhibition of DNA synthesis, the changes of Cx32 and claudin-1 returned to control levels, as did both functions. In treatment with the inhibitors before DNA synthesis, PD98059 inhibited the changes of expression and function of Cx32, but not claudin-1, without inhibition of cell growth, whereas LY294002 completely inhibited cell growth. These findings indicate that the PI3 kinase pathway rather than the MAP kinase pathway plays an important role for EGF-induced proliferation of rat hepatocytes, and that changes of Cx32 in hepatocytes during the stimulation of DNA synthesis may be in part controlled through MAP kinase. Furthermore, Cx32, but not claudin-1, protein may be a target of activated MAP kinase in hepatocytes.

Animals↗

PubMed2004

Tumor-derived heat shock protein 70-pulsed dendritic cells elicit tumor-specific cytotoxic T lymphocytes (CTLs) and tumor immunity.

Vaccination with autologous tumor-derived heat shock proteins (Hsp), such as Hsp70, Hsp90 and gp96, has been demonstrated to elicit specific immune responses against the tumor from which the Hsps were isolated. The effect of Hsp immunization is wholly dependent on the presence of functional antigen-presenting cells (APCs) in the immunized host, and Hsp receptors on APCs have recently been identified. Here we show that bone marrow-derived dendritic cells (DCs) are able to internalize HSP-peptide complex and that peptides are re-presented by DCs via the major histocompatibility complex (MHC) class I presentation pathway. In addition, immunization with tumor-derived HSP-pulsed DCs induces strong cytotoxic T cell (CTL) responses against multiple antigenic peptides in a transporter-associated antigen processing (TAP)-dependent manner. The results of the present study provide strong evidence of an efficient cross-priming activity of Hsp70, which could be exploited in the development of new and more effective immunotherapeutic strategies for cancer patients.

Animals↗

PubMed2004

Expression and function of tight junctions in the crypt epithelium of human palatine tonsils.

The human palatine tonsils have surface and crypt stratified epithelium and may be initiated via the epithelium to mount immune responses to various presenting antigens. Here we investigated the expression and function of tight junctions in the epithelium of human palatine tonsils from patients with tonsillar hypertrophy or recurrent tonsillitis. Occludin, ZO-1, JAM-1, and claudin-1, -3, -4, -7, -8, and -14 mRNAs were detected in tonsillar hypertrophy. Occludin and claudin-14 were expressed in the uppermost layer of the tonsil surface epithelium, whereas ZO-1, JAM-1, and claudin-1, -4, and -7 were found throughout the epithelium. In the crypt epithelium, claudin-4 was preferentially expressed in the upper layers. In freeze-fracture replicas, short fragments of continuous tight junction strands were observed but never formed networks. In the crypt epithelium of recurrent tonsillitis, the tracer was leaked from the surface regions where occludin and claudin-4 disappeared. Occludin, ZO-1, JAM-1, and claudin-1, -3, -4, and -14, but not claudin-7, mRNAs were decreased in recurrent tonsillitis compared with those of tonsillar hypertrophy. These studies suggest unique expression of tight junctions in human palatine tonsillar epithelium, and the crypt epithelium may possess an epithelial barrier different from that of the surface epithelium.

Adolescent↗

PubMed2003

Polymorphism of Clara cell 10-kD protein gene of sarcoidosis.

Clara cell 10-kD protein (CC10) exhibits potent antiinflammatory properties. G38A polymorphism was found in the CC10 gene. We investigated the genetic influence of the allele on the development of sarcoidosis using case control analysis in a Japanese population (265 sarcoidosis cases and 258 control subjects). The A allele frequency in sarcoidosis cases (45.1%) was significantly higher than healthy control subjects (34.9%, p = 0.0002). According to outcomes, we divided 223 patients with follow-up periods of 3 years or more into two subgroups (55 progressive and 168 regressive disease). The A allele frequency in patients with progressive disease was significantly higher than control subjects (odds ratio = 4.55; 95% confidence interval, 2.97-6.97; p < 0.0001), whereas that of regressive disease was not. The A/A genotypes had significantly lower bronchoalveolar lavage fluid CC10 levels than the G/G (nonsmokers, p = 0.0054, and smokers, p = 0.0045) and G/A genotypes (nonsmokers, p = 0.0022, and smokers, p = 0.0402). The reporter gene assay showed significantly lower reporter activities in the presence of interferon-gamma for the 38A construct than the 38G construct (p = 0.0177). The G38A polymorphism in the CC10 gene may influence protein expression and be associated with the development of progressive sarcoidosis.

Amino Acid Substitution↗

PubMed2003

Chymase-positive mast cells in small sized adenocarcinoma of the lung.

Mast cells accumulate in angiogenesis-dependent situations of lung adenocarcinoma. Human mast cells are divided into two major subsets: MCT (mast cells with immunoreactivity for tryptase but not chymase) and MCTC (reactive for tryptase and chymase). Chymase is an important mediator of tissue remodeling, but research into chymase-containing mast cell subpopulations has been hampered by the lack of reagents suitable for use with formalin-fixed tissue. We stained chymase using CC1 antibody in 66 cases of small sized lung adenocarcinoma as well as CD34 and tryptase. There were significant positive correlations of microvessel counts with MCT-type and MCTC-type mast cell counts in lung adenocarcinomas. When analyzed according to Noguchi's classification, MCT-type and MCTC-type mast cells were significantly increased in Noguchi type-C tumors [localized bronchioloalveolar carcinoma (LBAC) with active fibroblastic proliferation] compared with in Noguchi type-A (LBAC) plus type-B tumors (LBAC with alveolar collapse). Members in the high-count group of MCTC-type but not MCT-type mast cells showed a significantly worse outcome than those in the low-count group in LBACs. Counting chymase-positive (MCTC-type) mast cells in tumor stroma may be a good prognosis predictor for LBACs, especially Noguchi type-C tumors.

Adenocarcinoma↗

PubMed2003

Immunohistochemical analysis of the p53 family members in human craniopharyngiomas.

Craniopharyngiomas are intracranial tumors that usually arise in the site around the sella turcica. They are composed of distinctive sheets of epithelial cells showing adamantinomatous or squamous-papillary histologic types. Because little is known about the tumorigenesis of craniopharyngiomas, we retrieved samples from 15 tumor cases to investigate the functional significance of the p53 family of transcription factors, which are known to be expressed in various human epithelia. Immunohistochemical analysis of these cases demonstrated similar expression profiles of p53 family members in the two histologic types of the tumor; i.e., strong nuclear expression of p63 was observed in all cell layers, and moderate to intense nuclear expression of p73 was observed in the basal cell layers. In contrast to p63 and p73, the reactivity of an archetypal tumor suppressor, p53, was occasional and weak in the two histologic types. Because p63 was widely expressed in the tumors, reverse transcription-polymerase chain reaction (RT-PCR) analysis was conducted to elucidate which spliced variant of p63 was expressed. The results showed that deltaNp63, lacking a terminal transactivation domain of p63, was the dominant isoform. Together with the reported evidence that the deltaNp63 isoform is highly expressed in human squamous-cell carcinomas, these data suggest that the cellular architecture characteristic of the expression of p53 family members may be required for the histogenesis of craniopharyngiomas, where deltaNp63 has a possible role in maintaining proliferative activity of the tumor cells, like squamous-cell carcinomas in other tissues.

Adult↗

PubMed2003

Rapidly growing early gastric cancer with microsatellite instability.

A 77-year-old man underwent gastrointestinal endoscopy that revealed a small flat elevated lesion in the gastric antrum. Endoscopically, we assessed the tumor as intramucosal cancer or adenoma, and biopsy specimens were diagnosed as showing borderline malignancy. At the second examination, performed 6 months later, the elevated lesion had grown, showing remarkable changes in its appearance, and a diagnosis of adenocarcinoma was confirmed pathologically. The patient underwent distal gastrectomy about 8 months after the first examination, and the tumor in the resected specimens showed a moderately differentiated adenocarcinoma invading through the entire submucosal layer, with metastasis to a regional lymph node. Microsatellite analysis of this early gastric cancer disclosed mutations in all six markers examined, indicating high-level microsatellite instability (MSI-H). The tumor also showed frameshift mutations of TGFbetaRII and BAXgenes, as well as hypermethylation of the hMLH1promoter. These results suggest that a deficiency of the mismatch repair system played a critical role in the progression of this cancer.

Adenocarcinoma↗

PubMed2003

T-cell receptor variable gamma chain gene expression in the interaction between rat gammadelta-type T cells and heat-shock protein 70-like molecule.

We previously reported that rat T-cell receptor (TCR) Vdelta6 of T-cell hybridomas was preferentially involved in recognition of the cell surface-expressed 70 kDa rat heat-shock cognate (hsc70, a constitutively expressed member of the hsp 70 family) protein-like molecule (#067 molecule). In the present study, we analyzed usage of the TCR Vgamma family of #067-restricted T-cell hybridomas. Our data indicated that most of these hybridomas expressed transcripts of TCR Vgamma1 and/or Vgamma2. However, some of the Vgamma2 transcripts were out-of-frame, suggesting that the TCR Vgamma1 family may be important for the recognition of #067-defined molecules. TCR Vgamma1 transcripts were detected in not only #067-restricted T-cell hybridomas, but #067-non restricted ones as well. However, V-J nucleotide sequences of #067-restricted and #067-non restricted T-cell hybridomas suggested that #067-restricted T-cell hybridomas showed limited insertion of nucleotide stretch as compared with #067-non restricted ones. In terms of amino acids, only one amino acid was added in #067-restricted T-cell hybridomas, whereas two or three amino acids were added in #067-non restricted ones. These data suggest that the heterodimer of the TCR relatively short stretch form of Vgamma1 molecule and TCR Vdelta6 may participate in recognition of the #067 molecule.

Animals↗

PubMed2003

Histone H2AX sensitizes glioma cells to genotoxic stimuli by recruiting DNA double-strand break repair proteins.

Glioblastoma is a life-threatening tumor in the human brain despite the fact that radio-chemotherapy inducing DNA damage has been improved in the last decade. Various studies focusing on the enhancement of the susceptibility of glioblastoma cells to DNA damage have been reported, which are aimed at more efficient treatment for the tumor. In this study, we show that radioresistant T98G glioblastoma cells can develop sensitivity to DNA damage induced by irradiation and etoposide as a result of the introduction of a DNA repair-associated histone, H2AX. Interestingly, when H2AX-transformed T98G cells were irradiated, Brca1 and Nbs1 were readily recruited in DNA double-strand break (DSB) foci and showed the G2/M-phase arrest of the cell cycle. Moreover, up-regulation of Brca1 was observed in H2AX-T98G cells after exposure to irradiation. Together with the evidence that H2AX transfection does not affect growth activities of non-tumor cells under genotoxic stimuli, this suggests that H2AX gene transfer would provide a new modality for radio-chemotherapy for glioblastomas, probably through overcoming the instability of the genome, and that Brca1 and Nbs1 might be crucial in this methodology.

Antineoplastic Agents, Phytogenic↗