癌細胞におけるRNA結合タンパク質IMP3の機能解析

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 秋光 信佳, 東京大学教授 新井 洋由, 東京大学教授 後藤 由季子, 東京大学教授 村田 茂穂, 東京大学教授 関水 和久University of Tokyo(東京大学

Identification and Characterization of Novel Genotoxic Stress-Inducible Nuclear Long Noncoding RNAs in Mammalian Cells

Whole transcriptome analyses have revealed a large number of novel transcripts including long and short noncoding RNAs (ncRNAs). Currently, there is great interest in characterizing the functions of the different classes of ncRNAs and their relevance to cellular processes. In particular, nuclear long ncRNAs may be involved in controlling various aspects of biological regulation, such as stress responses. By a combination of bioinformatic and experimental approaches, we identified 25 novel nuclear long ncRNAs from 6,088,565 full-length human cDNA sequences. Some nuclear long ncRNAs were conserved among vertebrates, whereas others were found only among primates. Expression profiling of the nuclear long ncRNAs in human tissues revealed that most were expressed ubiquitously. A subset of the identified nuclear long ncRNAs was induced by the genotoxic agents mitomycin C or doxorubicin, in HeLa Tet-off cells. There were no commonly altered nuclear long ncRNAs between mitomycin C- and doxorubicin-treated cells. These results suggest that distinct sets of nuclear long ncRNAs play roles in cellular defense mechanisms against specific genotoxic agents, and that particular long ncRNAs have the potential to be surrogate indicators of a specific cell stress

Identification of Minimal p53 Promoter Region Regulated by MALAT1 in Human Lung Adenocarcinoma Cells

The MALAT1 long noncoding RNA is strongly linked to cancer progression. Here we report a MALAT1 function in repressing the promoter of p53 (TP53) tumor suppressor gene. p21 and FAS, well-known p53 targets, were upregulated by MALAT1 knockdown in A549 human lung adenocarcinoma cells. We found that these upregulations were mediated by transcriptional activation of p53 through MALAT1 depletion. In addition, we identified a minimal MALAT1-responsive region in the P1 promoter of p53 gene. Flow cytometry analysis revealed that MALAT1-depleted cells exhibited G1 cell cycle arrest. These results suggest that MALAT1 affects the expression of p53 target genes through repressing p53 promoter activity, leading to influence the cell cycle progression

Effects of rehabilitation program focused on improving real-life daily activities of patients with mild cognitive impairments or dementia and their caregivers

Objective: To evaluate the effectiveness of a dyadic outpatient rehabilitation program focused on improving the real-life daily activities of patients with mild cognitive impairments or dementia and their caregivers. Design: Retrospective study. Subjects: Eight patients with mild cognitive impairments or dementia and their caregivers. Methods: The rehabilitation program comprised eight 1-hour sessions by occupational therapists with patients and his/her caregivers. Patients were assessed for motor function, cognitive function, and quality of life, and their caregivers were assessed for depression and caregiver burden. Participants were assessed at pre-program and post-program, and 3-month follow-up. Results: The scores of caregiver-assessed Quality of life in Alzheimer’s disease scale in patients significantly improved at post-program (median [interquartile range], 30.0 [7.0]) compared with pre-program (27.0 [2.8], effect size = 0.77, p = 0.029). In caregivers, the Zarit Caregiver Burden Interview scores decreased significantly at post-program (16.5 [13.0]) compared with pre-program (22.0 [17.5], effect size = 0.72, p = 0.042). There were no significant differences in other assessments. Conclusions: The rehabilitation program focused on real daily activities and demonstrated to improve patients’ quality of life and caregivers’ depression and caring burden through patient-caregiver interaction. Future enhanced follow-up systems are warranted

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<p>The MALAT1 long noncoding RNA is strongly linked to cancer progression. Here we report a MALAT1 function in repressing the promoter of p53 (TP53) tumor suppressor gene. p21 and FAS, well-known p53 targets, were upregulated by MALAT1 knockdown in A549 human lung adenocarcinoma cells. We found that these upregulations were mediated by transcriptional activation of p53 through MALAT1 depletion. In addition, we identified a minimal MALAT1-responsive region in the P1 promoter of p53 gene. Flow cytometry analysis revealed that MALAT1-depleted cells exhibited G1 cell cycle arrest. These results suggest that MALAT1 affects the expression of p53 target genes through repressing p53 promoter activity, leading to influence the cell cycle progression.</p

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<p>The MALAT1 long noncoding RNA is strongly linked to cancer progression. Here we report a MALAT1 function in repressing the promoter of p53 (TP53) tumor suppressor gene. p21 and FAS, well-known p53 targets, were upregulated by MALAT1 knockdown in A549 human lung adenocarcinoma cells. We found that these upregulations were mediated by transcriptional activation of p53 through MALAT1 depletion. In addition, we identified a minimal MALAT1-responsive region in the P1 promoter of p53 gene. Flow cytometry analysis revealed that MALAT1-depleted cells exhibited G1 cell cycle arrest. These results suggest that MALAT1 affects the expression of p53 target genes through repressing p53 promoter activity, leading to influence the cell cycle progression.</p

Image4.tif

<p>The MALAT1 long noncoding RNA is strongly linked to cancer progression. Here we report a MALAT1 function in repressing the promoter of p53 (TP53) tumor suppressor gene. p21 and FAS, well-known p53 targets, were upregulated by MALAT1 knockdown in A549 human lung adenocarcinoma cells. We found that these upregulations were mediated by transcriptional activation of p53 through MALAT1 depletion. In addition, we identified a minimal MALAT1-responsive region in the P1 promoter of p53 gene. Flow cytometry analysis revealed that MALAT1-depleted cells exhibited G1 cell cycle arrest. These results suggest that MALAT1 affects the expression of p53 target genes through repressing p53 promoter activity, leading to influence the cell cycle progression.</p

Strategy for the selection of ncRNAs.

<p>(A) A schematic of the selection procedure for ncRNAs. They were selected based on their lack of susceptibility to nonsense-mediated RNA decay (NMD) and nuclear localization. The identities of the transcripts in each category are given in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0034949#pone-0034949-t001" target="_blank">Table 1</a>. (B) Schematic of aberrant mRNAs harboring a premature termination codon (PTC) and surveillance complexes containing UPF factors. EJC indicates an exon junction complex, which is an essential component for NMD in mammalian cells. (C) Details of the sub-cellular localization analysis of transcripts.</p

Expression of the genes neighboring stress-inducible nuclear long ncRNAs under MMC treatment.

<p>HeLa Tet-off (TO) cells were treated with MMC and subjected to qRT-PCR. (A) UT18-neighboring genes were co-regulated, whereas (B) UT6-neighboring genes were not. Error bars show the experimental error of two experiments.</p