879 research outputs found
Impact of One-Carbon Metabolism-Driving Epitranscriptome as a Therapeutic Target for Gastrointestinal Cancer
No full textOne-carbon (1C) metabolism plays a key role in biological functions linked to the folate cycle. These include nucleotide synthesis; the methylation of DNA, RNA, and proteins in the methionine cycle; and transsulfuration to maintain the redox condition of cancer stem cells in the tumor microenvironment. Recent studies have indicated that small therapeutic compounds affect the mitochondrial folate cycle, epitranscriptome (RNA methylation), and reactive oxygen species reactions in cancer cells. The epitranscriptome controls cellular biochemical reactions, but is also a platform for cell-to-cell interaction and cell transformation. We present an update of recent advances in the study of 1C metabolism related to cancer and demonstrate the areas where further research is needed. We also discuss approaches to therapeutic drug discovery using animal models and propose further steps toward developing precision cancer medicine
Bromodomain protein BRDT directs ΔNp63 function and super-enhancer activity in a subset of esophageal squamous cell carcinomas
No full textAbstract Esophageal squamous cell carcinoma (ESCC) is the predominant subtype of esophageal cancer with a particularly high prevalence in certain geographical regions and a poor prognosis with a 5-year survival rate of 15–25%. Despite numerous studies characterizing the genetic and transcriptomic landscape of ESCC, there are currently no effective targeted therapies. In this study, we used an unbiased screening approach to uncover novel molecular precision oncology targets for ESCC and identified the bromodomain and extraterminal (BET) family member bromodomain testis-specific protein (BRDT) to be uniquely expressed in a subgroup of ESCC. Experimental studies revealed that BRDT expression promotes migration but is dispensable for cell proliferation. Further mechanistic insight was gained through transcriptome analyses, which revealed that BRDT controls the expression of a subset of ΔNp63 target genes. Epigenome and genome-wide occupancy studies, combined with genome-wide chromatin interaction studies, revealed that BRDT colocalizes and interacts with ΔNp63 to drive a unique transcriptional program and modulate cell phenotype. Our data demonstrate that these genomic regions are enriched for super-enhancers that loop to critical ΔNp63 target genes related to the squamous phenotype such as KRT14 , FAT2 , and PTHLH . Interestingly, BET proteolysis-targeting chimera, MZ1, reversed the activation of these genes. Importantly, we observed a preferential degradation of BRDT by MZ1 compared with BRD2, BRD3, and BRD4. Taken together, these findings reveal a previously unknown function of BRDT in ESCC and provide a proof-of-concept that BRDT may represent a novel therapeutic target in cancer.Erich und Gertrud Roggenbuck-Stiftung https://doi.org/10.13039/100010124China Scholarship Council https://doi.org/10.13039/50110000454
Controlling lymph node micrometastases by neoadjuvant chemotherapy affects the prognosis in advanced esophageal squamous cell carcinoma
No full text学位の種類：医学 学位授与年月日：令和2年12月15日 主査： 教授 報告番号：甲第1461号 学内授与番号：医第1324号 Yoko Hiraki, Yutaka Kimura, Motohiro Imano, Hiroaki Kato, Mitsuru Iwama, Osamu Shiraishi, Atsushi Yasuda, Masayuki Shinkai, Tomoki Makino, Masaaki Motoori, Makoto Yamasaki, Hiroshi Miyata, Takao Satou, Taroh Satoh, Hiroshi Furukawa, Masahiko Yano, Yuichiro Doki & Takushi Yasuda. Surg Today. 2021 Jan;51(1):118-126. doi: 10.1007/s00595-020-02059-7. Epub 2020 Jun 28. http://link.springer.com/journal/595application/pdfdoctoral thesi
Abstract 4774: Polyamines are rich and induces epigenetic change by inhibition of LSD1 in cancer stem-like cells
No full textAbstract
Cancer stem cells (CSC) are highly tumorigenic and resistant to chemotherapy and radiotherapy. We have previously reported that a small fraction of cancer cells with low proteasome activity had CSC-like properties. Ornithine decarboxylase (ODC) is an enzyme which converts ornithine to polyamines including putrescine, spermidine, and spermine. Proteasomal degradation of ODC is known to be ubiquitin-independent. The aim of this study was to explain how low proteasome activity gave CSC-like properties. Western blot showed high ODC protein level in CSC-like cells in cervical cancer and osteosarcoma cell lines, although ODC mRNA level is not high. These findings suggest that ODC protein level is high in CSC-like cells because ODC protein degradation is inactive. To investigate polyamine metabolism in CSC-like cells, we performed GC-MS analysis and found that putrescine, spermidine, and spermine were enriched in CSC-like cells. Furthermore, flux analysis showed conversion from ornithine to polyamines was more rapid in CSC-like cells. We performed a computational structure analysis and found that polyamines bind and inhibit demethylase site of LSD1 which is known to be a demethylase of histone H3K4 and a nuclear homolog of amine oxidases. Spermine was the strongest binding energy. An enzyme assay showed that LSD1 activity was dose-dependently inhibited by polyamines and spermine was the strong inhibitor. Finally, we analyzed performed ChIP sequencing analysis by using HeLa CSC-like cells and found that more global enrichment of H3K4me3 and less global enrichment of H3K4me1 than non-CSC-like cells. In conclusion, polyamines are rich in CSC, and be able to inhibit LSD1 activty and induce epigenetic alterations especially in H3K4 methylation in CSC.
Citation Format: Keisuke Tamari, Hideshi Ishii, Masamitsu Konno, Naohiro Nishida, Jun Koseki, Koichi Kawamoto, Fumiaki Isohashi, Yuichiro Doki, Masaki Mori, Kazuhiko Ogawa. Polyamines are rich and induces epigenetic change by inhibition of LSD1 in cancer stem-like cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4774. doi:10.1158/1538-7445.AM2017-4774</jats:p
Abstract 3075: Analysis of microRNA profiles involved in the resistance to trifluridine
No full textAbstract
Background: Trifluridine (FTD) is a key component of the novel oral antitumor drug trifluridine/tipiracil, which was approved for the treatment of patients with metastatic colorectal cancer refractory to standard chemotherapies. A comprehensive analysis of miRNA profiles was performed in cell lines resistant to FTD established by ourselves, in order to explore the underlying mechanisms of resistance to the drug.
Method: We established subline resistance to FTD through continuous administration and increasing dose of the drug for 5 months using the colorectal cancer cell line DLD-1. Total RNA was extracted at intervals whilst establishing FTD resistant sublines, and miRNA expression was analyzed by microarray. The expression of miRNA that was significantly downregulated in the FTD resistant subline was knocked down to test its involvement in resistance to FTD. Cell viability was evaluated by crystal violet cytotoxicity test.
Results: The established FTD-resistant sublines showed more than 22-fold higher resistance to FTD and no cross-resistance to 5-FU. miRNA and mRNA clustered in the genome locus located in chromosome 9, 9p22.32 were downregulated in the FTD-resistant cell line, one of which was the miRNA let-7d-5p, which is one of the let-7 family and is known to target oncogenes and several key components of the cell cycle and cell proliferation. Anti-let-7d-5p treated DLD-1 was less sensitive to FTD than compared to control. The IC50 values of FTD were 16.8 µM and 7.6 µM for the anti-let-7d-5p treated cells and control respectively. On the other hand, overexpression of let-7d-5p in DLD-1 using let-7d-5p mimic increased the sensitivity to FTD compared to control. The IC50 values of FTD were 3.7 µM and 13.9 µM in the let-7d-5p overexpression cells and control respectively. 5FU sensitivity was only altered slightly in anti- let-7d-5p treated or let-7d-5p mimic treated cells. These data suggest that let-7d-5p is more relevant to sensitivity for FTD than that of 5FU.
Conclusion: Let-7d-5p expression level influenced FTD sensitivity more effectively than 5FU. It suggests that the let-7d-5p is a potential predictive marker for trifluridine/tipiracil treatment in the clinical setting.
Citation Format: Kenta Tsunekuni, Jun Koseki, Masamitsu Konno, Ayumu Asai, Norihiro Nishida, Hugh Colvin, Koichi Kawamoto, Yuichiro Doki, Masaki Mori, Hideshi Ishii. Analysis of microRNA profiles involved in the resistance to trifluridine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3075. doi:10.1158/1538-7445.AM2017-3075</jats:p
Gain-of-function oncogenic mutations in TP53 enhance defined factor-mediated cellular reprogramming
No full textCancer is a disorder with various genetic and epigenetic alterations. Genetic alterations such as mutations, i.e., substitutions, amplifications, and deletions of nucleotide sequences, are largely irreversible, whereas epigenetic alterations can be modified by pharmacological agents that target components of the epigenetic machinery. Recent studies have showed that introduction of defined factors such as those encoded by c-MYC, SOX2, OCT3/4, and KLF4 in normal somatic cells results in their dedifferentiation into induced pluripotent stem (iPS) cells. In addition, we have reported that these iPS factors induce the development of induced multipotent cancer (iPC) cells from gastrointestinal cancer cells by reducing tumor aggressiveness. The efficiency of iPS reprogramming increased when p53 was inhibited. The study of cancer cells suggests that the p53 pathways might be involved in the aggressive phenotypes of iPC cells in a long-term culture. However, the roles of gain-of-function oncogenic mutations in TP53, which is a key tumor suppressor gene, remain to be elucidated. We investigated reprogramming efficiency of iPS generation in human diploid fibroblasts that were co-transfected with TP53 mutants and defined factors. The results suggest that mutations in those TP53 regions that are involved in DNA contact might play a critical role in the efficiency of iPS generation. Taken together, our studies suggest 2 roles of TP53 mutations in reprogramming: (1) the structural mutations might contribute to, or collaborate with, other mutations to regulate the maintenance of genomic stability; (2) the DNA-contact mutations could affect the downstream target genes, which may be distinct from those involved in wild-type p53 function. These molecular manipulations of tumorigenicity and enhancement of cellular reprogramming efficiency by the p53 pathway will open an attractive and useful avenue for future medicine
Treatment of T4 Esophageal Cancer. Definitive Chemo-Radiotherapy vs Chemo-Radiotherapy Followed by Surgery
No full textInfluence of Bursectomy on Operative Morbidity and Mortality After Radical Gastrectomy for Gastric Cancer: Results of a Randomized Controlled Trial
No full textAbstract 2930: Niche microenvironments essential for tumor heterogeneity of primary cancer cells
No full textAbstract
Primary culture of cancer cells derived from each patient’s tumor can provide important information of the “individual tumor.” It is general to use cell lines in basic research filed. However, cell lines are quite different from clinical cancers. Clinical cancer tissues are composed of not only cancer cells but also tumor microenvironments such as stromal cells and tumor vessels. The primary culture method of clinical cancer with tumor niche microenvironments has not been optimized. We have developed a simple 2D-culture method for primary colorectal cancer (CRC). We obtained 30 samples from surgically resected tumor. They were mechanically and enzymatically digested and fibrotic tissue and bacteria were excluded using customized two size filters. And we cultured the obtained cells on a matrigel-coated plate with embryonic stem (ES) cells culture medium. We named these cultured cancer cells, “isolated-tumor derived Cancer Cells (iCCs).” All iCCs grew and about 80 % of iCCs were successfully passaged. Twenty-three iCCs were transplanted into the subcutaneous layer of NOD-SCID mice, and the tumor growth and histology of iCCs were examined. The morphology was similar to each parental clinical tumor. And microarray analysis showed that RNA expression of iCCs was similar to each parental tumor. Furthermore, we examined the culture medium; our modified ES culture medium (ES-cultured iCCs) and 10% FBS medium (serum-cultured iCCs). The expression of surface markers regarding cancer stem cells such as CD44 and CD24 were different between ES-cultured iCCs and serum-cultured iCCs, and drug sensitivity of iCCs were also different. FACS analysis and immunocytochemistry revealed that iCCs contained PDGFR-positive cells. The results of multi-drug sensitivity assay were different between iCCs and cell lines especially in PDGFR inhibitor. Strong correlations were observed between the results of multi-drug sensitivity assay of iCCs and clinical outcomes of chemotherapy. We report an innovative primary culture method and the in vivo and in vitro analyses of iCCs, leading to the future application.
Citation Format: Shiki Fujino, Norikatsu Miyoshi, Masayuki Ohue, Yusuke Takayashi, Masayoshi Yasui, Hidekazu Takahashi, Naoyuki Haraguchi, Jhunichi Nishimura, Taishi Hata, Tsunekazu Mizushima, Yuichiro Doki, Masaki Mori. Niche microenvironments essential for tumor heterogeneity of primary cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2930. doi:10.1158/1538-7445.AM2017-2930</jats:p
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