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| 3. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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- Chen, Chi-Kuan, et al.
(författare)
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Leukocyte cell-derived chemotaxin 2 antagonizes MET receptor activation to suppress hepatocellular carcinoma vascular invasion by protein tyrosine phosphatase 1B recruitment
- 2014
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Ingår i: Hepatology. - Hoboken : Wiley-Blackwell. - 0270-9139 .- 1527-3350. ; 59:3, s. 974-985
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Tidskriftsartikel (refereegranskat)abstract
- UNLABELLED: Leukocyte cell-derived chemotoxin 2 (LECT2) has been shown to act as a tumor suppressor in hepatocellular carcinoma (HCC). However, the underlying mechanism has not yet been completely defined. Here, we employ a LECT2-affinity column plus liquid chromatography coupled with tandem mass spectrometry to identify LECT2-binding proteins and found that MET receptor strongly interacted with LECT2 protein. Despite the presence of hepatocyte growth factor, the LECT2 binding causes an antagonistic effect to MET receptor activation through recruitment of protein tyrosine phosphatase 1B. The antagonistic effect of LECT2 on MET activation also mainly contributes to the blockage of vascular invasion and metastasis of HCC. Furthermore, serial deletions and mutations of LECT2 showed that the HxGxD motif is primarily responsible for MET receptor binding and its antagonistic effects.CONCLUSION: These findings reveal a novel, specific inhibitory function of LECT2 in HCC by the direct binding and inactivation of MET, opening a potential avenue for treating MET-related liver cancer.
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- Wang, Mei jun, et al.
(författare)
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SIRT1-dependent deacetylation of Txnip H3K9ac is critical for exenatide-improved diabetic kidney disease
- 2023
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Ingår i: Biomedicine and Pharmacotherapy. - 0753-3322. ; 167
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Tidskriftsartikel (refereegranskat)abstract
- Glucagon-like peptide 1 receptor agonist exenatide (exendin-4) has potential protective capabilities against diabetic kidney disease (DKD). However, the underlying mechanism has not been fully elucidated. The expression of thioredoxin-interacting protein (Txnip) is upregulated during DKD progression by histone acetylation. Sirtuin 1 (SIRT1) is a deacetylase and is decreased in DKD, which indicates that it may regulate Txnip in this disease. Here, we used whole-body heterozygous Sirt1 knockout (Sirt1+/-) and kidney-specific Sirt1 knockout (KSK) mice to investigate whether SIRT1 regulates Txnip via histone deacetylation in DKD and exenatide-alleviated DKD. Exenatide substantially improved renal pathological damage, decreased the albumin-to-creatinine ratio (ACR), upregulated SIRT1 expression, and downregulated Txnip expression in kidneys of high-fat diet-treated C57BL/6J mice. However, these effects diminished in Sirt1+/- and KSK mice under exenatide treatment. The downregulation of Txnip expression by exendin-4 in high-glucose-treated SV40 MES13 cells was hampered during Sirt1 knockdown. These results demonstrate that kidney SIRT1 is indispensable in exenatide-improved DKD and downregulation of Txnip expression. Exendin-4 mechanistically downregulated Txnip histone 3 lysine 9 acetylation (H3K9ac) in a SIRT1-dependent manner and decreased spliced X-box binding protein 1 (XBP1s) recruitment to the Txnip promoter. These findings provide epigenetic evidence elucidating the specific mechanism for exenatide-mediated DKD alleviation and highlight the importance of Txnip as a promising therapeutic target for DKD.
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 7. |
- Campbell, PJ, et al.
(författare)
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Pan-cancer analysis of whole genomes
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 578:7793, s. 82-
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Tidskriftsartikel (refereegranskat)abstract
- Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale1–3. Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4–5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter4; identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation5,6; analyses timings and patterns of tumour evolution7; describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity8,9; and evaluates a range of more-specialized features of cancer genomes8,10–18.
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| 8. |
- Chen, Min-Wei, et al.
(författare)
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H3K9 histone methyltransferase G9a promotes lung cancer invasion and metastasis by silencing the cell adhesion molecule Ep-CAM
- 2010
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Ingår i: Cancer Research. - : American Association for Cancer Research. - 0008-5472 .- 1538-7445. ; 70:20, s. 7830-7840
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Tidskriftsartikel (refereegranskat)abstract
- G9a is a mammalian histone methyltransferase that contributes to the epigenetic silencing of tumor suppressor genes. Emerging evidence suggests that G9a is required to maintain the malignant phenotype, but the role of G9a function in mediating tumor metastasis has not been explored. Here, we show that G9a is expressed in aggressive lung cancer cells, and its elevated expression correlates with poor prognosis. RNAi-mediated knockdown of G9a in highly invasive lung cancer cells inhibited cell migration and invasion in vitro and metastasis in vivo. Conversely, ectopic G9a expression in weakly invasive lung cancer cells increased motility and metastasis. Mechanistic investigations suggested that repression of the cell adhesion molecule Ep-CAM mediated the effects of G9a. First, RNAi-mediated knockdown of Ep-CAM partially relieved metastasis suppression imposed by G9a suppression. Second, an inverse correlation between G9a and Ep-CAM expression existed in primary lung cancer. Third, Ep-CAM repression was associated with promoter methylation and an enrichment for dimethylated histone H3K9. G9a knockdown reduced the levels of H3K9 dimethylation and decreased the recruitment of the transcriptional cofactors HP1, DNMT1, and HDAC1 to the Ep-CAM promoter. Our findings establish a functional contribution of G9a overexpression with concomitant dysregulation of epigenetic pathways in lung cancer progression.
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| 9. |
- Chien, Ming-Hsien, et al.
(författare)
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Vascular endothelial growth factor-C (VEGF-C) promotes angiogenesis by induction of COX-2 in leukemic cells via the VEGF-R3/JNK/AP-1 pathway.
- 2009
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 30:12, s. 2005-13
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Tidskriftsartikel (refereegranskat)abstract
- Vascular endothelial growth factor (VEGF)-C is recognized as a tumor lymphangiogenic factor based on the effects of activated VEGF-R3 on lymphatic endothelial cells. Many tumor cells express VEGF-R3 but the function of this receptor in tumor cells is largely unknown. It has been reported that the VEGF-C/VEGF-R3 axis is activated in subsets of leukemia patients. Herein, we have shown that VEGF-C induces angiogenic activity in the tube formation assay invitro and Matrigel plug assay in vivo by upregulating an angiogenic factor, cyclooxygenase-2 (COX-2), through VEGF-R3 in the human acute myeloid leukemia (AML) cell line, THP-1. COX-2 induction by VEGF-C was also observed in other VEGF-R3(+) human AML cell lines (U937 and HL60). Moreover, immunohistochemical analysis of bone marrow specimens of 37 patients diagnosed with AML revealed that VEGF-C expression in specimens was associated with the expression of COX-2 (P < 0.001). The manner by which signaling pathways transduced by VEGF-C is responsible for COX-2 upregulation was further investigated. Blocking the p42/44 mitogen-activated protein kinase (MAPK) pathway with the MAPK kinase inhibitor, PD 98059, failed to inhibit VEGF-C-mediated COX-2 expression. However, VEGF-C-induced COX-2 upregulation was effectively abolished by overexpression of dominant-negative c-Jun N-terminal kinase (JNK) or treatment with the JNK inhibitor, SP 600125. VEGF-C induced JNK-dependent nuclear translocation of c-Jun. Furthermore, chromatin immunoprecipitation and reporter assays revealed that VEGF-C enhanced c-Jun binding to the cyclic adenosine 3',5'-monophosphate-response element of the COX-2 promoter and induced COX-2 expression. In sum, the data herein highlight the pathogenic role of VEGF-C in leukemia via regulation of angiogenesis through upregulation of COX-2.
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| 10. |
- Hua, Kuo-Tai, et al.
(författare)
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N-α-acetyltransferase 10 protein suppresses cancer cell metastasis by binding PIX proteins and inhibiting Cdc42/Rac1 activity
- 2011
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Ingår i: Cancer Cell. - : Cell Press. - 1535-6108 .- 1878-3686. ; 19:2, s. 218-231
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Tidskriftsartikel (refereegranskat)abstract
- N-α-acetyltransferase 10 protein, Naa10p, is an N-acetyltransferase known to be involved in cell cycle control. We found that Naa10p was expressed lower in varieties of malignancies with lymph node metastasis compared with non-lymph node metastasis. Higher Naa10p expression correlates the survival of lung cancer patients. Naa10p significantly suppressed migration, tumor growth, and metastasis independent of its enzymatic activity. Instead, Naa10p binds to the GIT-binding domain of PIX, thereby preventing the formation of the GIT-PIX-Paxillin complex, resulting in reduced intrinsic Cdc42/Rac1 activity and decreased cell migration. Forced expression of PIX in Naa10-transfected tumor cells restored the migration and metastasis ability. We suggest that Naa10p functions as a tumor metastasis suppressor by disrupting the migratory complex, PIX-GIT- Paxillin, in cancer cells.
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