Biomedical subjects

Mayumi Iwakawa

Publications and source records attributed to Mayumi Iwakawa.

17 recordsLinked to original sources

PubMed2006

Cyclooxygenase-2 impairs treatment effects of radiotherapy for cervical cancer by inhibition of radiation-induced apoptosis.

PURPOSE: Cyclooxygenase-2 (COX-2) plays a pivotal role in regulation of radiation-induced apoptosis. The aim of this study was to analyze the relationship between COX-2 expression and postradiotherapy outcomes of patients with cervical cancer. METHODS AND MATERIALS: Biopsy specimens from 47 consecutive patients who had undergone definitive radiotherapy alone or radiotherapy combined with chemotherapy between October 2002 and November 2004 were investigated. RESULTS: The COX-2 expression rate of the pretreatment samples was 46.1% +/- 21.0%, and the apoptotic index (AI) 1 week after start of radiotherapy was 2.1% +/- 0.9%. There was a significant negative correlation between the pretreatment COX-2 expression and the AI during radiotherapy (r = -0.52, p = 0.0002). Complete response rates were 59% for COX-2-positive patients compared with 80% for COX-2-negative patients (p = 0.12). The 2-year local control rate for COX-2-positive patients was 71.3%, whereas the corresponding rate for COX-2-negative patients was 96.0% (p = 0.06). CONCLUSIONS: To the best of our knowledge, this is the first report to prove clinically that COX-2 can make cervical squamous cell carcinomas more refractory to radiotherapy by inhibition of radiation-induced apoptosis. Furthermore, expression of COX-2 may be a good indicator to predict local tumor control after radiotherapy. Although long-term results are ultimately needed, the combination therapy of radiotherapy with use of a COX-2 inhibitor could yield improved outcomes for patients with COX-2 expressing cervical cancer.

Adult↗

PubMed2006

Gene expression profile changes correlating with radioresistance in human cell lines.

PURPOSE: To identify gene expression profiles specific to radioresistance of human cells. METHODS AND MATERIALS: Global gene expression profiles of a total of 15 tumor and normal fibroblast cell lines were analyzed using DNA microarrays and statistical clustering methods. Initially, six of the cell lines were categorized into radioresistant (RG) or nonradioresistant (NRG) groups according to the radiation dose required to reduce their survival to 10% (D10). Genes for which expression was specific to each group at 1 or 3 h after irradiation were identified using statistical procedures including analysis of variance and a two-dimensional hierarchical clustering method. The remaining nine cell lines were subjected to the k-nearest neighbor pattern classification. RESULTS: The nine test cell lines were successfully classified by their D10 value using 46 and 44 genes for which transcription levels had significantly changed at 1 and 3 h after irradiation, respectively. Of these genes, 25 showed altered expression at both time points in the NRG or RG, but independently were unable to classify the test cell lines. CONCLUSIONS: Radioresistant cell lines analyzed in this study showed certain radiation-induced changes in gene expression profiles that are different from the profile changes of the more-sensitive cell lines.

Cell Line, Tumor↗

PubMed2006

Reliable and fast allele-specific extension of 3'-LNA modified oligonucleotides covalently immobilized on a plastic base, combined with biotin-dUTP mediated optical detection.

In the present work, a convenient microarray SNP typing system has been developed using a plastic base that covalently immobilizes amino-modified oligonucleotides. Reliable SNP allele discrimination was achieved by using allelic specificity-enhanced enzymatic extension of immobilized oligonucleotide primer, with a locked nucleic acid (LNA) modification at the SNP-discriminating 3'-end nucleotide. Incorporation of multiple biotin-dUTP molecules during primer extension, followed by binding of alkaline phosphatase-conjugated streptavidin, allowed optical detection of the genotyping results through precipitation of colored alkaline phosphatase substrates onto the surface of the plastic base. Notably, rapid primer extension was demonstrated without a preliminary annealing step of double-stranded template DNA, allowing overall processes to be performed within a couple of hours. Simultaneous evaluation of three SNPs in the genes TGFB1, SOD2 and APEX1, previously investigated for association with radiation sensitivity, in 25 individuals has shown perfect assignment with data obtained by another established technique (MassARRAY system).

Alkaline Phosphatase↗

PubMed2006

Analysis of non-genetic risk factors for adverse skin reactions to radiotherapy among 284 breast cancer patients.

OBJECTIVES: We analyzed non-genetic risk factors for adverse skin reactions to irradiation at 4 collaborating Japanese institutions, to design future investigation into genetic risk factors for adverse skin reactions to irradiation in a multicenter setting. METHODS: From April 2001, 284 breast cancer patients, who underwent radiotherapy with breast-conserving surgery, were enrolled from 4 collaborating institutions in Japan. We graded skin reactions according to international scoring systems. Clinical factors were tested against adverse effects. RESULTS: Grade 1+ skin reactions were observed in 261 (92%) of the patients in less than 3 months, 118 (42%) at 3 months, and 29 (10%) at 6 months in the late phase. Univariate analysis of treatment risk factors (such as the use of a multi-leaf colimeter, wedge-filter, or immobilization device) for skin reactions revealed a significant association (p< 0.0001). After a variable selection procedure with logistic regression, the institution, operative procedure, and magnitude of photon energy remained significantly associated with acute skin reactions. Only the institution was an explanatory variable for skin reactions at 3 and 6 months in the final logistic model. CONCLUSION: After stratification, substantial remaining variations in the occurrence of skin reactions of a given level suggested that individual genetic factors contribute markedly to individual radiosensitivity. Analysis of genetic factors associated with adverse effects would be possible by stratifying patients according to institution. Selection of eligible institutions, where appropriate treatment modalities could be performed, would also be possible when planning such a study.

Adult↗

PubMed2005

DNA repair capacity measured by high throughput alkaline comet assays in EBV-transformed cell lines and peripheral blood cells from cancer patients and healthy volunteers.

We collected peripheral blood (PB) from 556 patients with various types of cancer who had undergone radiotherapy and from 81 healthy volunteers. We exposed whole PB and Epstein-Barr virus-transformed lymphoblastoid cell lines (EBLs) derived from the PB mononucleocytes to X-irradiation (5 Gy). Using the alkaline comet assay, we measured the immediate DNA damage and, at 15 min, the % residual damage. In PB, the immediate damage was similar in patients and healthy volunteers while the % residual damage (mean+/-S.D.) was significantly higher in patients with breast (54.3+/-A23.9), cervical (54.7+/-A23.9), head/neck (56.8+/-A24.4), lung (60.1+/-23.5), or esophageal cancers (59.5+/-A33.7) than in healthy donors (42.9+/-19.6) (P<0.05). We did not observe such differences in the EBV-transformed cell lines. Thus, radiation sensitivity of fresh PB cells measured by the alkaline comet assay was related to cancer status.

Blood Donors↗

PubMed2005

Molecular markers predicting radiotherapy response: report and recommendations from an International Atomic Energy Agency technical meeting.

PURPOSE: There is increasing interest in radiogenomics and the characterization of molecular profiles that predict normal tissue and tumor radioresponse. A meeting in Amsterdam was organized by the International Atomic Energy Agency to discuss this topic on an international basis. METHODS AND MATERIALS: This report is not completely exhaustive, but highlights some of the ongoing studies and new initiatives being carried out worldwide in the banking of tumor and normal tissue samples underpinning the development of molecular marker profiles for predicting patient response to radiotherapy. It is generally considered that these profiles will more accurately define individual or group radiosensitivities compared with the nondefinitive findings from the previous era of cellular-based techniques. However, so far there are only a few robust reports of molecular markers predicting normal tissue or tumor response. RESULTS: Many centers in different countries have initiated tissue and tumor banks to store samples from clinical trials for future molecular profiling analysis, to identify profiles that predict for radiotherapy response. The European Society for Therapeutic Radiology and Oncology GENEtic pathways for the Prediction of the effects of Irradiation (GENEPI) project, to store, document, and analyze sample characteristics vs. response, is the most comprehensive in this regard. CONCLUSIONS: The next 5-10 years are likely to see the results of these and other correlative studies, and promising associations of profiles with response should be validated in larger definitive trials.

Biomarkers, Tumor↗

PubMed2005

Pulmonary metastases after nephrectomy only for small, stage I/favorable-histology Wilms' tumor.

The prognosis for children with Wilms' tumor is reported to be excellent in those who are less than 2 years of age at diagnosis and who have a stage I/favorable-histology tumor with specimen weight less than 550 g. We report on a patient with Wilms' tumor who belonged to this group but who developed pulmonary metastases, and we discuss the diagnostic and therapeutic problems in such patients. The importance of careful evaluation of the renal sinus should be emphasized.

Fatal Outcome↗

PubMed2005

Inter-strain variance in late phase of erythematous reaction or leg contracture after local irradiation among three strains of mice.

AIM: To gain insights into inter-strain differences in radiosensitivity. METHODS: Mice of inbred strains, A/J, C57BL/6J, and C3H/HeMs, were irradiated at graded doses ranging from 20 to 60 Gy. Skin reaction and leg contraction were observed for a period of 230 days and between 175 and 350 days, respectively. Gene expressions in leg skin tissue were quantified by quantitative RT-PCR assay at 1, 12 and 72 h after 30 Gy irradiation. Mice were locally irradiated by using a Cs-137 source. RESULTS: The three strains showed various degrees of susceptibility to irradiation has evaluated by skin scores. Large inter-strain differences were also detected in the lengths of contraction. Expressions of several genes such as Per3 and Rad51ap1 displayed inter-strain differences. CONCLUSIONS: The continuum model of tissue injury revealed that genetic factor, which varies among strains, is one of the causes of variances in severity of damage after irradiation.

Animals↗

PubMed2005

Strain-dependent differences in locomotor activity after local brain irradiation with 30 GyE of carbon ions.

This study investigated strain differences in brain damage among male A/J, C57BL/6JNrs and C3H/HeNrs mice after local brain irradiation. Whole brains were irradiated with a single dose of 30 GyE carbon ion beams and then locomotor activity was determined as body heat of each animal. The daily locomotor activities of untreated mice differed among strains. Non-irradiated C57BL/6JNrs mice were more active than A/J mice. This variance became more obvious immediately after irradiation, when the activity of A/J and C3H/HeNrs mice diminished, whereas that of C57BL/6JNrs mice increased at the beginning of the active phase and remained elevated for three days after irradiation. The altered activities of all three strains of irradiated mice gradually recovered to normal within three to four days.

Animals↗

PubMed2004

Effects of carbon-ion beams on human pancreatic cancer cell lines that differ in genetic status.

The relative biologic effectiveness (RBE) of carbon-ion beams at 3 different linear energy transfer (LET) values (13, 50, and 80 keV/microm) accelerated by the Heavy Ion Medical Accelerator in Chiba on human pancreatic cancer cell lines differing in genetic status was determined. The RBE values were calculated as D10, the dose (Gy) required to reduce the surviving fraction to 10%, relative to X-rays. We also investigated apoptosis and the relationship between D10 and the cell cycle checkpoint using morphologic examination and flow cytometry analysis, respectively. The RBE values calculated by the D10 values ranged from 1.16 to 1.77 for the 13-keV/microm beam and from 1.83 to 2.46 for the 80-keV/microm beam. A correlation between the D10 values of each cell line and intensity of G2/M arrest was observed. In contrast, LET values did not clearly correlate with induction of apoptosis. These results suggest that carbon-ion beam therapy is a promising modality. Elucidation of the mechanisms of G2/M arrest and apoptosis may provide clues to enhancing the effects of radiation on pancreatic cancer.

Apoptosis↗

PubMed2004

Strain dependent differences in a histological study of CD44 and collagen fibers with an expression analysis of inflammatory response-related genes in irradiated murine lung.

Using a mouse model, we investigated the mechanisms of heterogeneity in response to ionizing radiation in this research. C57BL/6J and C3H/HeMs mice were irradiated with gamma rays at 10 and 20 Gy. The animals were sacrificed at times corresponding to the latent period, the pneumonic phase, and the start of the fibrotic phase for histological investigation. Small areas of fibrosis initially appeared in C57BL/6J mice at 4 weeks postirradiation with 20 Gy, whereas small inflammatory lesions appeared at 4 and 8 weeks after 20 and 10 Gy, respectively. The alveoli septa were thickened by an infiltration of inflammatory cells, and alveoli were obliterated in lungs from C57BL/6J mice after 20 Gy irradiation. At 24 hours and from 2 to 4 weeks postirradiation, fourfold more CD44 positive cells had accumulated in the lungs of C3H/HeMs than in C57BL/6J mice. Hyaluronan accumulated 12 hours after irradiation, and the rapid resolution was achieved within 2 weeks in the lungs in both strains of mice. C57BL/6J mice lungs accumulated dense collagen at 8 weeks. Quantitative RT-PCR assay was performed for several genes selected by cDNA microarray analysis. The expression of several genes, such as Cap1, Il18, Mmp12, Per3, Ltf, Ifi202a, and Rad51ap1 showed strain-dependent variances. In conclusion, a histological investigation suggested that C3H/HeMs mice were able to induce a more rapid clearance of matrix after irradiation than C57BL/6J mice. The expression analysis showed that the several genes are potentially involved in interstrain differences in inflammatory response causing radiation-induced lung fibrosis.

Animals↗

PubMed2004

Fractionated irradiation augments inter-strain variation of skin reactions among three strains of mice.

The multifraction regimens commonly used in conventional clinical radiotherapy are largely based on radiobiological experiments. However, no experimental reports on skin reactions focusing on inter-strain differences have displayed clinical relevance to the fractionated dose schedule. In this study, mice of inbred strains A/J, C57BL/6J, and C3H/HeMs were used to reveal inter-strain difference after multifractionated irradiation. Irradiation was performed daily at graded doses of 30-60 Gy total doses, with 10 fractions of 3-6 Gy. Acute skin reactions following irradiation were scored for 50 days after irradiation. Dividing a dose into a number of fractions obviously spared skin damage in the three strains of mice. No mouse exhibited a skin damage score more than 1.5, while single dose irradiation resulted in skin damage scores up to 3. The three different strains, however, showed varying susceptibility to fractionated irradiation within the range under 1.5. C3H/HeMs did not display any skin reaction after irradiation with 40 Gy total dose, while C57BL/6J and A/J demonstrated various skin reactions. Different latent periods of damage were also observed among the strains after irradiation at each dose. Our data suggest that genetic factors cause obvious variations in severity of damage and latent period after fractionated irradiation.

Animals↗

PubMed2004

Radiosensitivity of peripheral blood lymphocytes obtained from patients with cancers of the breast, head and neck or cervix as determined with a micronucleus assay.

The in vitro radiation sensitivities of peripheral blood lymphocytes obtained from 48 normal females and 168 female cancer patients were measured with the cytokinesis-blocking micronucleus assay. Cancer patients group had significantly higher mean baseline micronucleus frequency than normal healthy controls. Breast cancer patients were more radiosensitive than normal individuals. Cervical cancer cases were less radiation sensitive than normal subjects. The relative lack of radiation sensitivity in cervical-cancer cases could be due to modification of the radiosensitivity of patients' immune-responsible cells by human papillomaviruses infection. Normal individuals and cancer patients were classified according to their radiation sensitivity which was evaluated with the radiation-induced micronucleus frequencies. Such a classification will be an important initial step to characterize the radiosensitive, radioresistant, or cancer-prone individuals using specific SNP typing.

Adult↗

PubMed2003

Loss of CpG methylation is strongly correlated with loss of histone H3 lysine 9 methylation at DMR-LIT1 in patients with Beckwith-Wiedemann syndrome.

To clarify the chromatin-based imprinting mechanism of the p57(KIP2)/LIT1 subdomain at chromosome 11p15.5 and the mouse ortholog at chromosome 7F5, we investigated the histone-modification status at a differentially CpG methylated region of Lit1/LIT1 (DMR-Lit1/LIT1), which is an imprinting control region for the subdomain and is demethylated in half of patients with Beckwith-Wiedemann syndrome (BWS). Chromatin-immunoprecipitation assays revealed that, in both species, DMR-Lit1/LIT1 with the CpG-methylated, maternally derived inactive allele showed histone H3 Lys9 methylation, whereas the CpG-unmethylated, paternally active allele was acetylated on histone H3/H4 and methylated on H3 Lys4. We have also investigated the relationship between CpG methylation and histone H3 Lys9 methylation at DMR-LIT1 in patients with BWS. In a normal individual and in patients with BWS with normal DMR-LIT1 methylation, histone H3 Lys9 methylation was detected on the maternal allele; however, it disappeared completely in the patients with the DMR-LIT1 imprinting defect. These findings suggest that the histone-modification status at DMR-Lit1/LIT1 plays an important role in imprinting control within the subdomain and that loss of histone H3 Lys9 methylation, together with CpG demethylation on the maternal allele, may lead to the BWS phenotype.

Base Sequence↗

PubMed2003

Different radiation susceptibility among five strains of mice detected by a skin reaction.

Published reports about skin reactions to radiotherapy, especially among breast-cancer patients, suggest that there are interindividual differences in the normal tissue response, and genetic factors are thought to be involved in this variation. An analysis of murine strain differences may reveal the mechanism of genetic factors in the extent of normal tissue damage from irradiation for several endpoints. The variation in the radiation susceptibility was observed when the skin of mice from strains A/J, C3H/HeMs, C57BL/6J, C.B.17/Icr-scid and C3H-scid was irradiated with a single dose ranging from 10 to 60 Gy, using Cs-137 gamma rays. The active skin reaction of A/J mice lasted for months. C3H/HeMs mice showed dose-dependent skin damage, and consequently recovered to a state of mild damage within 40 days after local irradiation. The time course of the response in C57BL/6J mice was shorter than in A/J mice. The 2 strains of scid mice exhibited severe damage after irradiation at any dose from 20 to 50 Gy, and did not show any dose dependency. The variation between murine strains in macroscopic and histopathological changes in skin during the progression and resolution of damage caused by irradiation suggests an inter-strain variation in the expression of genes involved in injury, apoptosis, repair, and remodeling.

Animals↗

PubMed2002

[RadGenomics project].

Human health conditions are largely determined by a complex interplay among genetic susceptibility, environmental factors, and aging. The RadGenomics project, which began in April 2001, promotes analysis of genes in response to irradiation, identification of their allelic variants in the human population, development of an effective procedure for quantitating individual radio-sensitivity, and analysis of the interrelationship between genetic heterogeneity and susceptibility to irradiation. Major groups of genes with which the project will concern itself include DNA repair genes, cell cycle genes, oncogenes, tumor suppressor genes, genes for programmed cell death, genes for signal transduction, and genes for oxidative processes. The outcome of the RadGenomics project should lead to improved protocols for personalized radiotherapy and reduce the possible side effects of treatment. The project will contribute to future research on the molecular mechanisms of radiation sensitivity in humans and stimulate the development of new high-throughput technology for a broader application of the biological and medical sciences. Identification of functionally important polymorphisms in the radiation response genes may determine individual differences in sensitivity to radiation exposure. The staff members, who are specialists in a variety of fields including genome science, radiation biology, medical science, molecular biology, and bioinformatics, have come to the RadGenomics project from various universities, companies, and research institutes.

Animals↗

PubMedDate not supplied

Modified radiosensitivity of pancreatic cancer xenografts by farnesyl protein transferase inhibitor and MEK inhibitor.

We investigated the effects of the farnesyl transferase inhibitor (FTI) manumycin and the MEK inhibitor PD98059 on growth of human pancreatic cancer, with mutant (SUIT2) or wild-type (BxPC-3) K-ras, xenografted into nude mice. Tumor growth was not reduced by either of the agents at a dose of 3 mg/kg without irradiation. Growth of SUIT2 irradiated at 15 Gy or 30 Gy was reduced by manumycin and PD98059: at 15 Gy, tumor volume doubling time (TVDT) increased from 18.6+/-3.8 to 36.3+/-14.2 days with PD98059 (p<0.05); at 30 Gy, TVDT increased from 32.8+/-6.8 to 70.5+/-10.5 days and 70.7+/-1.5 days, respectively. Manumycin tended to reduce growth of BxPC-3, but the difference in TVDT was not statistically significant. PD98059 significantly increased the TVDT of BxPC-3 at 30 Gy from 34.4+/-18 to 62.6+/-9.8 at 30 Gy. The present results suggest that Ras signaling pathways are potential targets for manipulation of radiosensitivity, and that induction of an alternative pathway may enhance radiosensitivity of pancreatic cancer.

Alkyl and Aryl Transferases↗