151
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Rahl PB, Lin CY, Seila AC, Flynn RA, McCuine S, Burge CB, Sharp PA, Young RA. c-Myc regulates transcriptional pause release. Cell 2010; 141:432-45. [PMID: 20434984 DOI: 10.1016/j.cell.2010.03.030] [Citation(s) in RCA: 995] [Impact Index Per Article: 71.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 01/14/2010] [Accepted: 02/21/2010] [Indexed: 12/30/2022]
Abstract
Recruitment of the RNA polymerase II (Pol II) transcription initiation apparatus to promoters by specific DNA-binding transcription factors is well recognized as a key regulatory step in gene expression. We report here that promoter-proximal pausing is a general feature of transcription by Pol II in mammalian cells and thus an additional step where regulation of gene expression occurs. This suggests that some transcription factors recruit the transcription apparatus to promoters, whereas others effect promoter-proximal pause release. Indeed, we find that the transcription factor c-Myc, a key regulator of cellular proliferation, plays a major role in Pol II pause release rather than Pol II recruitment at its target genes. We discuss the implications of these results for the role of c-Myc amplification in human cancer.
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Affiliation(s)
- Peter B Rahl
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
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152
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Albihn A, Johnsen JI, Henriksson MA. MYC in oncogenesis and as a target for cancer therapies. Adv Cancer Res 2010; 107:163-224. [PMID: 20399964 DOI: 10.1016/s0065-230x(10)07006-5] [Citation(s) in RCA: 181] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
MYC proteins (c-MYC, MYCN, and MYCL) regulate processes involved in many if not all aspects of cell fate. Therefore, it is not surprising that the MYC genes are deregulated in several human neoplasias as a result from genetic and epigenetic alterations. The near "omnipotency" together with the many levels of regulation makes MYC an attractive target for tumor intervention therapy. Here, we summarize some of the current understanding of MYC function and provide an overview of different cancer forms with MYC deregulation. We also describe available treatments and highlight novel approaches in the pursuit for MYC-targeting therapies. These efforts, at different stages of development, constitute a promising platform for novel, more specific treatments with fewer side effects. If successful a MYC-targeting therapy has the potential for tailored treatment of a large number of different tumors.
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Affiliation(s)
- Ami Albihn
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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153
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Zhao D, Liu Z, Ding J, Li W, Sun Y, Yu H, Zhou Y, Zeng J, Chen C, Jia J. Helicobacter pylori CagA upregulation of CIP2A is dependent on the Src and MEK/ERK pathways. J Med Microbiol 2009; 59:259-265. [PMID: 19959630 DOI: 10.1099/jmm.0.014704-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Helicobacter pylori is classified as a class I carcinogenic factor and its persistent colonization in the stomach induces gastric cancer. Cancerous Inhibitor of PP2A (CIP2A) is a newly identified oncoprotein overexpressed in gastric cancer. Serving as a key oncoprotein, CIP2A also participates in regulation of senescence and proliferation of gastric cells. The combination of aberrant CIP2A expression inducing unlimited cell proliferation, and H. pylori infection eliciting aberrant expression of some key proteins, results in the onset of gastric tumorigenesis. However, the relationship between H. pylori infection and CIP2A expression still remains undefined. The aim of our study was to verify the effect of H. pylori infection on CIP2A expression levels and identify H. pylori signalling molecules and corresponding pathways influencing CIP2A expression. Following plasmid-mediated expression of CagA in human gastric cell lines, the cells were infected with H. pylori and CIP2A expression levels were examined by immunoblotting. Signal inhibitors were used to verify which signal pathways were involved. We also performed CIP2A depletion and H. pylori infection after depletion in AGS cells. H. pylori infection-induced CIP2A expression was dependent on cagA gene expression and CagA phosphorylation. Bacterial oncoprotein CagA upregulated CIP2A expression and this upregulation effect was dependent on Src and Ras/mitogen-activated protein kinase kinase/extracellular signal-regulated kinase pathways. H. pylori infection-induced Myc stabilization was partially attenuated by CIP2A depletion. The results of our study provide further information for understanding the mechanism of H. pylori carcinogenesis.
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Affiliation(s)
- Dapeng Zhao
- Department of Microbiology and Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, PR China
| | - Zhifang Liu
- Department of Biochemistry, School of Medicine, Shandong University, Jinan, PR China
| | - Jian Ding
- Department of Microbiology and Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, PR China
| | - Wenjuan Li
- Department of Microbiology and Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, PR China
| | - Yundong Sun
- Department of Microbiology and Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, PR China
| | - Han Yu
- Department of Microbiology and Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, PR China
| | - Yabin Zhou
- Department of Microbiology and Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, PR China
| | - Jiping Zeng
- Department of Biochemistry, School of Medicine, Shandong University, Jinan, PR China
| | - Chunyan Chen
- Department of Microbiology and Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, PR China
| | - Jihui Jia
- Department of Microbiology and Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, PR China
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