Jinichi Mori

Regulation of iron homeostasis by the p53-ISCU pathway.

Accumulation of iron in tissues increases the risk of cancer, but iron regulatory mechanisms in cancer tissues are largely unknown. Here, we report that p53 regulates iron metabolism through the transcriptional regulation of ISCU (iron-sulfur cluster assembly enzyme), which encodes a scaffold protein that plays a critical role in Fe-S cluster biogenesis. p53 activation induced ISCU expression through binding to an intronic p53-binding site. Knockdown of ISCU enhanced the binding of iron regulatory protein 1 (IRP1), a cytosolic Fe-S protein, to an iron-responsive element in the 5′ UTR of ferritin heavy polypeptide 1 (FTH1) mRNA and subsequently reduced the translation of FTH1, a major iron storage protein. In addition, in response to DNA damage, p53 induced FTH1 and suppressed transferrin receptor, which regulates iron entry into cells. HCT116 p53+/+ cells were resistant to iron accumulation, but HCT116 p53−/− cells accumulated intracellular iron after DNA damage. Moreover, excess dietary iron caused significant elevation of serum iron levels in p53−/− mice. ISCU expression was decreased in the majority of human liver cancer tissues, and its reduced expression was significantly associated with p53 mutation. Our finding revealed a novel role of the p53-ISCU pathway in the maintenance of iron homeostasis in hepatocellular carcinogenesis.

Cystatin C as a p53‐inducible apoptotic mediator that regulates cathepsin L activity

In response to various cellular stresses, p53 is activated and inhibits malignant transformation through the transcriptional regulation of its target genes. However, the full picture of the p53 downstream pathway still remains to be elucidated. Here we identified cystatin C, a major inhibitor of cathepsins, as a novel p53 target. In response to DNA damage, activated p53 induced cystatin C expression through p53 binding sequence in the first intron. We showed that cathepsin L activity was decreased in HCT116 p53+/+ cells after adriamycin treatment, but not in HCT116 p53−/− cells. We also found that knockdown of cystatin C reduced adriamycin‐induced caspase‐3 activation. Cystatin C expression was significantly downregulated in breast cancer cells with p53 mutations, and decreased cystatin C expression was associated with poor prognosis of breast cancer. Our findings revealed an important role of the p53–cystatin C pathway in human carcinogenesis.

Differences in drug approval processes of 3 regulatory agencies: a case study of gemtuzumab ozogamicin

SummaryMajor discrepancies concerning risk-benefit assessments and regulatory actions are frequent among regulatory agencies. We explored the differences by scrutinizing a case of gemtuzumab ozogamicin (GO) in patients with acute myeloid leukaemia (AML). Assessment reports of GO were retrieved form the websites of the US Food and Drug Administration (FDA), the European Medicines Agency (EMA) and Japanese regulatory agency, and we also reviewed published clinical trials. While GO was approved by the US FDA under the accelerated approval program in 2000, it was withdrawn from the market in 2010, based on the required post-marketing commitment failure. The EMA refused granting marketing authorization for GO in 2008 on the grounds that there were no randomised controlled trials (RCTs). GO was approved as an orphan drug in Japan in 2005, and the Japanese regulatory authority decided to continue with the approval in 2010 on the condition that post-marketing surveillance is strengthened. Under these situations, promising new results of RCTs appeared in 2011, and the role of GO in AML treatment was refocused worldwide. The stringent regulation may not be suitable in case of an orphan drug of targeted therapy, and more room should be kept to facilitate effective developments of new anti-neoplastic agents.

The Transcriptional Landscape of p53 Signalling Pathway

Although recent cancer genomics studies have identified a large number of genes that were mutated in human cancers, p53 remains as the most frequently mutated gene. To further elucidate the p53-signalling network, we performed transcriptome analysis on 24 tissues in p53+/+ or p53−/− mice after whole-body X-ray irradiation. Here we found transactivation of a total of 3551 genes in one or more of the 24 tissues only in p53+/+ mice, while 2576 genes were downregulated. p53 mRNA expression level in each tissue was significantly associated with the number of genes upregulated by irradiation. Annotation using TCGA (The Cancer Genome Atlas) database revealed that p53 negatively regulated mRNA expression of several cancer therapeutic targets or pathways such as BTK, SYK, and CTLA4 in breast cancer tissues. In addition, stomach exhibited the induction of Krt6, Krt16, and Krt17 as well as loricrin, an epidermal differentiation marker, after the X-ray irradiation only in p53+/+ mice, implying a mechanism to protect damaged tissues by rapid induction of differentiation. Our comprehensive transcriptome analysis elucidated tissue specific roles of p53 and its signalling networks in DNA-damage response that will enhance our understanding of cancer biology.

Regulation of myo-inositol biosynthesis by p53-ISYNA1 pathway

In response to various cellular stresses, p53 exerts its tumor suppressive effects such as apoptosis, cell cycle arrest, and senescence through the induction of its target genes. Recently, p53 was shown to control cellular homeostasis by regulating energy metabolism, glycolysis, antioxidant effect, and autophagy. However, its function in inositol synthesis was not reported. Through a microarray screening, we found that five genes related with myo-inositol metabolism were induced by p53. DNA damage enhanced intracellular myo-inositol content in HCT116 p53+/+ cells, but not in HCT116 p53-/- cells. We also indicated that inositol 3-phosphate synthase (ISYNA1) which encodes an enzyme essential for myo-inositol biosynthesis as a direct target of p53. Activated p53 regulated ISYNA1 expression through p53 response element in the seventh exon. Ectopic ISYNA1 expression increased myo-inositol levels in the cells and suppressed tumor cell growth. Knockdown of ISYNA1 caused resistance to adriamycin treatment, demonstrating the role of ISYNA1 in p53-mediated growth suppression. Furthermore, ISYNA1 expression was significantly associated with p53 mutation in bladder, breast cancer, head and neck squamous cell carcinoma, lung squamous cell carcinoma, and pancreatic adenocarcinoma. Our findings revealed a novel role of p53 in myo-inositol biosynthesis which could be a potential therapeutic target.

Increased incidence of dog-bite injuries after the Fukushima nuclear accident.

OBJECTIVE The objective of this study is to assess the localized incidence of dog bites following the nuclear accident related to the Great East Japan Earthquake in March 2011. METHODS We identified the patients with dog bites in our hospital in Minamisoma City, Fukushima, during the period from 1year prior to the earthquake to 3.5months following it, and calculated the monthly and weekly incidence proportions by dividing the patient number by the total emergency room visits. We also analyzed the data by the characteristics of the patients. RESULTS We identified 27 dog-bite cases during the post-disaster period. The median monthly incidence proportion during the pre-disaster period and the highest monthly incidence proportion during the post-disaster period were 0.21 and 6.50 per 100 visits, respectively. The weekly incidence proportion peaked at 3weeks after the earthquake and thereafter decreased to the baseline level. CONCLUSION The Fukushima nuclear accident may be associated with an increased incidence of dog bites, and the prolonged evacuation in response to the radiation contamination may have prolonged the increased incidence after the disaster. Physicians and local residents should recognize this potential hazard. Countermeasures to contend with this risk should be a mandatory aspect of disaster preparedness, including for nuclear accidents.

Effect of cytogenetic risk status on outcomes for patients with acute myeloid leukemia undergoing various types of allogeneic hematopoietic cell transplantation: an analysis of 7812 patients

Abstract This study aimed at determining how cytogenetic risk status affects outcomes for patients with acute myeloid leukemia (AML) after undergoing various types of allogeneic hematopoietic cell transplantation (HCT). Of 7812 patients eligible for analysis, cytogenetic risk was classified as favorable for 1088, intermediate for 5025, and poor for 1699. Overall, multivariate analysis showed significant intergroup differences in terms of relapse and survival, with the difference between poor- and intermediate-risk groups being greater than that between favorable- and intermediate-risk groups. Non-relapse mortality was identical for the three groups. Significant effects of cytogenetic risk status on survival were documented irrespective of donor type (related, unrelated, and umbilical cord blood), disease status at the time of transplantation (first or second complete remission, and more advanced disease status), and conditioning intensity (myeloablative and reduced-intensity). Our findings demonstrate robust and constant effects of cytogenetic risk status on survival after allogeneic HCT for patients with AML.

Minimal Internal Radiation Exposure in Residents Living South of the Fukushima Daiichi Nuclear Power Plant Disaster.

Following the Fukushima nuclear power plant disaster, assessment of internal radiation exposure was indispensable to predict radiation-related health threats to residents of neighboring areas. Although many evaluations of internal radiation in residents living north and west of the crippled Fukushima nuclear power plant are available, there is little information on residents living in areas south of the plant, which were similarly affected by radio-contamination from the disaster. To assess the internal radio-contamination in residents living in affected areas to the south of the plant or who were evacuated into Iwaki city, a whole body counter (WBC) screening program of internal radio-contamination was performed on visitors to the Jyoban hospital in Iwaki city, which experienced less contamination than southern areas adjacent to the nuclear plant. The study included 9,206 volunteer subjects, of whom 6,446 were schoolchildren aged 4–15 years. Measurements began one year after the incident and were carried out over the course of two years. Early in the screening period only two schoolchildren showed Cs-137 levels that were over the detection limit (250 Bq/body), although their Cs-134 levels were below the detection limit (220 Bq/body). Among the 2,760 adults tested, 35 (1.3%) had detectable internal radio-contamination, but only for Cs-137 (range: 250 Bq/body to 859 Bq/body), and not Cs-134. Of these 35 subjects, nearly all (34/35) showed elevated Cs-137 levels only during the first year of the screening. With the exception of potassium 40, no other radionuclides were detected during the screening period. The maximum annual effective dose calculated from the detected Cs-137 levels was 0.029 and 0.028 mSv/year for the schoolchildren and adults, respectively, which is far below the 1 mSv/year limit set by the government of Japan. Although the data for radiation exposure during the most critical first year after the incident are unavailable due to a lack of systemic measurements, the present results suggest that internal radio-contamination levels more than one year after the incident were minimal for residents living south of the crippled Fukushima nuclear plant, and that the annual additional effective doses derived from internal Cs contamination were negligible. Thus, internal radio-contamination of residents living in southern radio-contaminated areas appears to be generally well controlled.

Hydroxycarbamide use in young children with sickle-cell anaemia.

www.thelancet.com Vol 378 November 19, 2011 1777 the Responsibility Deal—eg, the need for robust, independent, transparent scrutiny of commitments made and the benefi ts of a local approach. Public health sits within a wider socioeconomic system. The project was developed to operate at this scale by a public health team in the region that was prepared to take a risk with an unproven concept. Critics need to accept that insuffi cient evidence that an intervention is meeting planned outcomes because of short follow-up times does not equal evidence that such initiatives do not work. The scepticism with which projects of this nature have been met suggests a partisan view made on preformed conclusions rather than objective evidence. A reconsideration of this stance is in order.

Outcomes of Allogeneic Hematopoietic Cell Transplantation in Acute Myeloid Leukemia Patients with Abnormalities of the Short Arm of Chromosome 17

We retrospectively analyzed a Japanese nationwide database to elucidate the impact of abnormalities in the short arm of chromosome 17 (abnl[17p]) on the outcomes of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with acute myeloid leukemia. Of 10,923 patients, 262 (2.4%) had abnl(17p), 235 of whom were classified into the poor cytogenetic risk group according to the National Comprehensive Cancer Network criteria. The median follow-up period was 1425 days. In abnl(17p) versus non-abnl(17p) patients of poor cytogenetic risk group, overall survival (OS), disease-free survival, cumulative incidence of disease relapse, and nonrelapse mortality rates at 5 years after allo-HSCT were 9.2% versus 27.4%, 7.8% versus 25.0%, 66.6% versus 49.4%, and 25.6% versus 25.6%, respectively. In contrast to the other types of abnl(17p), isochromosome 17q rarely encompassed the poor cytogenetic risk traits and did not adversely affect OS. Among the abnl(17p) patients, male sex, nonremission disease status at transplantation, and poor cytogenetic risk group were significantly associated with shorter OS. In conclusion, the presence of an abnl(17p) negatively affects allo-HSCT outcomes, which are influenced by the type of abnormality. Prompt initiation of allo-HSCT during complete remission may improve outcomes.