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  • 1
    In: Oncotarget, Impact Journals, LLC, Vol. 8, No. 41 ( 2017-09-19), p. 70695-70706
    Type of Medium: Online Resource
    ISSN: 1949-2553
    URL: Issue
    Language: English
    Publisher: Impact Journals, LLC
    Publication Date: 2017
    detail.hit.zdb_id: 2560162-3
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  • 2
    Online Resource
    Online Resource
    American Association for Cancer Research (AACR) ; 2016
    In:  Cancer Research Vol. 76, No. 14_Supplement ( 2016-07-15), p. 5240-5240
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 76, No. 14_Supplement ( 2016-07-15), p. 5240-5240
    Abstract: Non-alcoholic fatty liver disease (NAFLD), which is strongly associated with metabolic syndrome, has become one of the most common causes of chronic liver disease in developed countries. Some patients with NAFLD develop a more serious form of the disease, non-alcoholic steatohepatitis (NASH), and NASH can develop cirrhosis or even hepatocellular carcinoma (HCC). Although hepatic retinoid (vitamin A) stores are progressively lost during the development of liver diseases, how this affects NAFLD/NASH and NASH-related hepatocarcinogenesis is unknown. In order to investigate this, we used streptozotocin (STZ) and high-fat diet (HFD) to induce NASH and related hepatic tumorigenesis in matched wild-type and lecithin:retinol acyltransferase (LRAT) knockout (KO) mice, which lack stored retinoid in the liver. LRAT is the sole enzyme responsible for hepatic retinyl ester synthesis since LRAT KO mice completely lack lipid droplets in hepatic stellate cells. Mice were injected with STZ within 48 hours after birth and then fed HFD from 4 to 16 weeks of age. At the termination of the experiment, liver tumors were observed macroscopically and microscopically in both groups. In LRAT KO mice, the development of hepatic adenoma and HCC was significantly suppressed compared to control group. LRAT KO mice showed decreased expression levels of cyclin D1 and TGF-beta mRNA in the liver. The serum levels of d-ROMs and BAP were measured and the d-ROM/BAP ratio, which indicates oxidative stress, markedly decreased in LRAT KO mice. The fibrosis in the liver of the LRAT KO mice was decreased. In addition, liver fibrosis in LRAT KO mice was suppressed. These findings indicate that LRAT KO mice are less susceptible to STZ and HFD-induced liver tumorigenesis due to regulation of cell cycle and attenuation of oxidative stress. The amount of hepatic retinoid may affect the progression of NASH and the development of NASH-related HCC. Citation Format: Takayasu Ideta, Yohei Shirakami, Tsuneyuki Miyazaki, Hiroyasu Sakai, Takuji Tanaka, William S. Blaner, Masahito Shimizu. Lacking hepatic retinoid storage in mice suppresses NASH-related hepatocarcinogenesis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5240.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2016
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    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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  • 3
    Online Resource
    Online Resource
    American Association for Cancer Research (AACR) ; 2013
    In:  Cancer Research Vol. 73, No. 8_Supplement ( 2013-04-15), p. 181-181
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 73, No. 8_Supplement ( 2013-04-15), p. 181-181
    Abstract: Retinoids are known to possess anti-cancer effects and a clinical trial of a synthetic retinoid for hepatocellular carcinoma (HCC) is ongoing recently in Japan. Hepatic retinoid metabolism is usually impaired during development of liver diseases. Loss of retinoid-containing lipid droplets upon hepatic stellate cell (HSC) activation is one of the first events in the development of liver diseases and retinoid stores are progressively lost from HSCs leading to hepatic fibrosis, cirrhosis, and HCC. In the present study, we employed two types of genetically-modified mice for investigating hepatic retinoid metabolism and signaling in diethylnitrosamine (DEN)-induced mouse hepatocarcinogenesis models. One is lecithin:retinol acyltransferas (LRAT) knockout (KO) mouse which lacks HSC lipid droplets and has much less hepatic retinoid stores, and the other is a transgenic mouse which expresses dominant negative form of retinoic acid receptor (dnRAR) to block retinoid signaling in the liver. Male 15 day-old mice were given intraperitoneal injections of DEN (25 mg/kg body weight). Eight-month-old DEN-treated Lrat KO mice showed lower liver tumor incidence and dnRAR transgenic mice showed higher incidence than that of respective control mice. In the acute phase after DEN injection, dnRAR transgenic mice exhibited higher hepatic levels of inflammatory cytokines. Two days after DEN injection, lower serum levels of alanine aminotransferase and decreased hepatic levels of cyclin D1 were observed in Lrat KO mice. Lrat KO mice also exhibited increased levels of retinoic acid-responsive genes, including p21, lower levels of cytochrome P450 enzymes required for DEN-bioactivation, and higher levels of the DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT). Our results indicate that Lrat KO mice, instead of almost no hepatic retinoid storage, are less susceptible to DEN-induced hepatocarcinogenesis due to increased hepatic retinoid signaling which is accompanied by higher expression of p21 in the liver. In conclusion, retinoid signaling plays a key role in these hepatocarcinogenesis models. Citation Format: Yohei Shirakami, William S. Blaner, Masahito Shimizu, Hisataka Moriwaki, Mitsuru Seishima. Hepatic retinoid signaling in mouse hepatocarcinogenesis models. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 181. doi:10.1158/1538-7445.AM2013-181
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2013
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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  • 4
    Online Resource
    Online Resource
    American Association for Cancer Research (AACR) ; 2011
    In:  Cancer Research Vol. 71, No. 8_Supplement ( 2011-04-15), p. 5555-5555
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 71, No. 8_Supplement ( 2011-04-15), p. 5555-5555
    Abstract: The liver is the main tissue site of retinoid storage in the body and the non-parenchymal hepatic stellate cell (HSC) is the major cellular site of retinoid storage within the liver. Loss of retinoid-containing lipid droplets (LDs) from HSCs is one of the first events in the development of hepatic diseases, leading progressively to liver fibrosis, cirrhosis and hepatocellular carcinoma. Although the loss of LDs is a hallmark of HSC activation, the contribution of hepatic retinoid storage to hepatic injury and hepatocarcinogenesis remains unknown. Lecithin:retinol acyltransferase (LRAT) is the sole enzyme responsible for storing hepatic retinoid and LRAT knockout (KO) mice lack liver retinoid stores. Retinol-binding protein (RBP) is the principal transport protein for retinol in the blood. RBP KO mice are unable to mobilize hepatic retinoid stores and have significantly more retinoid storage in the liver compared to wild type (WT) mice. In this study, we investigated the effects of endogenous retinoids on hepatic injury and hepatocarcinogenesis. We induced hepatic injury and HCC using diethylnitrosamine (DEN) in WT, LRAT KO and RBP KO mice. Both acute (for 24 and 48 hours after DEN administration) and long-term (for 8 months after DEN administration) studies were undertaken. After DEN injection of WT, LRAT KO, and RBP KO mice, serum levels of alanine transaminase (ALT) were significantly lower and Cyclin D1 and Ki-67 mRNA expression levels were decreased in the livers of the KOs compared to WT mice. This suggests that LRAT KO and RBP KO mice are less susceptible to DEN-induced liver injury and following compensatory proliferation. Furthermore, 8-month-old DEN-treated LRAT KO (n = 18) and RBP KO (n = 13) mice showed lower HCC incidence, fewer tumors, and smaller tumors than DEN-treated WT mice (n = 24). Five-month-old male LRAT KO and RBP KO mice showed higher expression levels of retinoic acid (RA) responsive genes, such as Cyp26A1 and RARβ, mRNA in their liver compared to WT, indicating that RA signaling is upregulated in the livers of the KOs’ mice. The expression levels of p21 mRNA in LRAT KO and RBP KO mice liver were higher than WT at several time points in both acute and long-term studies. Together these results suggest that increased RA signaling and associated higher p21 expression play important roles in the lower susceptibility of these mouse models to liver injury and hepatocarcinogenesis. We are presently investigating other possibilities that the presence/absence through which endogenous hepatic retinoids might have effects on hepatic diseases, probably by modulating several cancer signaling pathways, regulating apoptosis of hepatocytes and cancer cells, or influencing the tumor-surrounding microenvironment. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5555. doi:10.1158/1538-7445.AM2011-5555
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2011
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    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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  • 5
    Online Resource
    Online Resource
    Elsevier BV ; 2012
    In:  Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids Vol. 1821, No. 1 ( 2012-01), p. 124-136
    In: Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids, Elsevier BV, Vol. 1821, No. 1 ( 2012-01), p. 124-136
    Type of Medium: Online Resource
    ISSN: 1388-1981
    RVK:
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2012
    detail.hit.zdb_id: 2209502-0
    SSG: 12
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  • 6
    Online Resource
    Online Resource
    American Association for Cancer Research (AACR) ; 2010
    In:  Cancer Research Vol. 70, No. 8_Supplement ( 2010-04-15), p. 83-83
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 70, No. 8_Supplement ( 2010-04-15), p. 83-83
    Abstract: The liver is the main tissue site of retinoid (vitamin A and its derivatives) storage in the body and the non-parenchymal hepatic stellate cell (HSC) is the major cellular site of retinoid storage within the liver. Lipid droplets of HSCs contain a number of bioactive metabolites including retinoids. Following liver injury, HSCs undergo a process known as activation. Loss of retinyl esters, the retinoid storage form, and lipid droplets from HSCs is one of the first events in the development of hepatic disease, leading progressively to liver fibrosis, cirrhosis and hepatocellular carcinoma (HCC). Although the loss of lipid droplets is a hallmark of HSC activation, whether it is a cause or consequence of the HSC activation process is unclear. Moreover, the contribution of the loss of hepatic retinoid storage to hepatic injury and hepatocarcinogenesis remains unknown. To investigate the role of hepatic retinoid storage and retinoid-containing lipid droplets in hepatic injury and hepatocarcingenesis, we studied diethynitrosamine (DEN)-induced HCC in lecithin:retinol acyltransferase (LRAT) knockout (KO) mice, which lack retinoid-containing lipid droplets in their HSCs, and in retinol-binding protein (RBP) KO mice, which are unable to mobilize hepatic retinoid stores. We measured a number of factors implicated in hepatic injury and cancer initiation. Using an acute hepatic injury model for investigating cancer initiation, assessment of mRNA levels by qRT-PCR of TNF alpha and TGF beta in livers of LRAT KO mice indicated that these mice were more susceptible to cancer initiation than WT mice. On the other hand RBP KO mice showed less susceptibility. LRAT KO mice showed higher levels of CYP26A1, a gene whose expression is known to be highly and directly responsive to retinoic acid level, suggesting that hepatic retinoic acid levels in LRAT KO mice were higher than that of WT, and that this may influence hepatic injury and carcinogenesis. Overall, our data suggest that hepatic retinoid storage can influence the progression of hepatic disease. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 83.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2010
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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  • 7
    Online Resource
    Online Resource
    American Association for Cancer Research (AACR) ; 2012
    In:  Cancer Research Vol. 72, No. 8_Supplement ( 2012-04-15), p. 4428-4428
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 72, No. 8_Supplement ( 2012-04-15), p. 4428-4428
    Abstract: Retinoids are known to possess anti-cancer effects and a clinical trial of a synthetic retinoid for hepatocellular carcinoma (HCC) is ongoing recently in Japan. Loss of retinoid-containing lipid droplets upon hepatic stellate cell (HSC) activation is one of the first events in the development of liver disease leading to hepatocellular carcinoma (HCC). Although retinoid stores are progressively lost from HSCs during the development of hepatic disease, how this affects hepatocarcinogenesis is unclear. To investigate this, we used diethylnitrosamine (DEN) to induce hepatic tumorigenesis in matched wild-type (WT) and lecithin:retinol acyltransferase (LRAT) knockout (KO) mice, which lack stored retinoid and HSC lipid droplets. Male 15 day-old WT or Lrat KO mice were given intraperitoneal injections of DEN (25 mg/kg body weight). Eight months later Lrat KO mice showed significantly less liver tumor development compared to WT mice, characterized by less liver tumor incidence and smaller tumor size. Two days after DEN injection, lower serum levels of alanine aminotransferase and decreased hepatic levels of cyclin D1 were observed in Lrat KO mice. Lrat KO mice also exhibited increased levels of retinoic acid-responsive genes, including p21, lower levels of cytochrome P450 enzymes required for DEN-bioactivation, and higher levels of the DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT), both before and after DEN treatment. Our results indicate that Lrat KO mice are less susceptible to DEN-induced hepatocarcinogenesis due to increased retinoid signaling and higher expression of p21, which is accompanied by altered hepatic levels of DEN-activating enzymes and MGMT in Lrat KO mice also contribute to decreased cancer initiation and suppressed liver tumor development. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4428. doi:1538-7445.AM2012-4428
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2012
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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