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Title: MAML1 regulates cell viability via the NF-{kappa}B pathway in cervical cancer cell lines

Abstract

The Notch signaling pathway plays important roles in tumorigenesis in a context-dependent manner. In human cervical cancer, alterations in Notch signaling have been reported, and both tumor-suppressing and tumor-promoting roles of Notch signaling have been proposed; however, the precise molecular mechanisms governing these roles in cervical cancer remain controversial. MAML is a transcriptional co-activator originally identified by its role in Notch signaling. Recent evidence suggests that it also plays a role in other signaling pathways, such as the p53 and {beta}-catenin pathways. MAML is required for stable formation of Notch transcriptional complexes at the promoters of Notch target genes. Chromosomal translocations affecting MAML have been shown to promote tumorigenesis. In this study, we used a truncated dominant-negative MAML1 (DN-MAML) to investigate the role of MAML in HPV-positive cervical cancer cell lines. Three human cervical cancer cell lines (HeLa, SiHa and CaSki) expressed all Notch receptors and the Notch target genes Hes1 and MAML1. Among these 3 cell lines, constitutive appearance of cleaved Notch1 was found only in CaSki cells, which suggests that Notch1 is constitutively activated in this cell line. Gamma secretase inhibitor (GSI) treatment, which suppresses Notch receptor activation, completely abrogated this form of Notch1 but had no effectmore » on cell viability. Overexpression of DN-MAML by retroviral transduction in CaSki cells resulted in significant decreases in the mRNA levels of Hes1 and Notch1 but had no effects on the levels of MAML1, p53 or HPV E6/E7. DN-MAML expression induced increased viability of CaSki cells without any effect on cell cycle progression or cell proliferation. In addition, clonogenic assay experiments revealed that overexpression of DN-MAML resulted in increased colony formation compared to the overexpression of the control vector. When the status of the NF-{kappa}B pathway was investigated, CaSki cells overexpressing DN-MAML exhibited loss of phospho-I{kappa}B{alpha}, decreased total I{kappa}B{alpha} and nuclear localization of NF-{kappa}B p65, which suggests that the NF-{kappa}B pathway is hyperactivated. Furthermore, increased level of cleaved Notch1 was detected when DN-MAML was expressed. When DN-MAML-overexpressing cells were treated with GSI, significantly decreased cell viability was observed, indicating that inhibition of Notch signaling using GSI treatment and DN-MAML expression negatively affects cell viability. Taken together, targeting Notch signaling using DN-MAML and GSI treatment may present a novel method to control cell viability in cervical cancer cells.« less

Authors:
 [1];  [2];  [1];  [1];  [3];  [4]
  1. Medical Microbiology Interdisciplinary Program, Graduate School, Chulalongkorn University, Payathai Road, Pathumwan, Bangkok 10330 (Thailand)
  2. Biotechnology Program, Faculty of Science, Chulalongkorn University, Payathai Road, Pathumwan, Bangkok 10330 (Thailand)
  3. (Thailand)
  4. Department of Microbiology, Faculty of Science, Chulalongkorn University, Payathai Road, Pathumwan, Bangkok 10330 (Thailand)
Publication Date:
OSTI Identifier:
22212161
Resource Type:
Journal Article
Journal Name:
Experimental Cell Research
Additional Journal Information:
Journal Volume: 317; Journal Issue: 13; Other Information: Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0014-4827
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; CELL CYCLE; CELL PROLIFERATION; COLONY FORMATION; GENES; INHIBITION; MESSENGER-RNA; NEOPLASMS; PROMOTERS; RECEPTORS; TRANSLOCATION; VIRUSES

Citation Formats

Kuncharin, Yanin, Sangphech, Naunpun, Kueanjinda, Patipark, Bhattarakosol, Parvapan, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Payathai Road, Pathumwan, Bangkok 10330, and Palaga, Tanapat, E-mail: tanapat.p@chula.ac.th. MAML1 regulates cell viability via the NF-{kappa}B pathway in cervical cancer cell lines. United States: N. p., 2011. Web. doi:10.1016/J.YEXCR.2011.05.005.
Kuncharin, Yanin, Sangphech, Naunpun, Kueanjinda, Patipark, Bhattarakosol, Parvapan, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Payathai Road, Pathumwan, Bangkok 10330, & Palaga, Tanapat, E-mail: tanapat.p@chula.ac.th. MAML1 regulates cell viability via the NF-{kappa}B pathway in cervical cancer cell lines. United States. doi:10.1016/J.YEXCR.2011.05.005.
Kuncharin, Yanin, Sangphech, Naunpun, Kueanjinda, Patipark, Bhattarakosol, Parvapan, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Payathai Road, Pathumwan, Bangkok 10330, and Palaga, Tanapat, E-mail: tanapat.p@chula.ac.th. Mon . "MAML1 regulates cell viability via the NF-{kappa}B pathway in cervical cancer cell lines". United States. doi:10.1016/J.YEXCR.2011.05.005.
@article{osti_22212161,
title = {MAML1 regulates cell viability via the NF-{kappa}B pathway in cervical cancer cell lines},
author = {Kuncharin, Yanin and Sangphech, Naunpun and Kueanjinda, Patipark and Bhattarakosol, Parvapan and Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Payathai Road, Pathumwan, Bangkok 10330 and Palaga, Tanapat, E-mail: tanapat.p@chula.ac.th},
abstractNote = {The Notch signaling pathway plays important roles in tumorigenesis in a context-dependent manner. In human cervical cancer, alterations in Notch signaling have been reported, and both tumor-suppressing and tumor-promoting roles of Notch signaling have been proposed; however, the precise molecular mechanisms governing these roles in cervical cancer remain controversial. MAML is a transcriptional co-activator originally identified by its role in Notch signaling. Recent evidence suggests that it also plays a role in other signaling pathways, such as the p53 and {beta}-catenin pathways. MAML is required for stable formation of Notch transcriptional complexes at the promoters of Notch target genes. Chromosomal translocations affecting MAML have been shown to promote tumorigenesis. In this study, we used a truncated dominant-negative MAML1 (DN-MAML) to investigate the role of MAML in HPV-positive cervical cancer cell lines. Three human cervical cancer cell lines (HeLa, SiHa and CaSki) expressed all Notch receptors and the Notch target genes Hes1 and MAML1. Among these 3 cell lines, constitutive appearance of cleaved Notch1 was found only in CaSki cells, which suggests that Notch1 is constitutively activated in this cell line. Gamma secretase inhibitor (GSI) treatment, which suppresses Notch receptor activation, completely abrogated this form of Notch1 but had no effect on cell viability. Overexpression of DN-MAML by retroviral transduction in CaSki cells resulted in significant decreases in the mRNA levels of Hes1 and Notch1 but had no effects on the levels of MAML1, p53 or HPV E6/E7. DN-MAML expression induced increased viability of CaSki cells without any effect on cell cycle progression or cell proliferation. In addition, clonogenic assay experiments revealed that overexpression of DN-MAML resulted in increased colony formation compared to the overexpression of the control vector. When the status of the NF-{kappa}B pathway was investigated, CaSki cells overexpressing DN-MAML exhibited loss of phospho-I{kappa}B{alpha}, decreased total I{kappa}B{alpha} and nuclear localization of NF-{kappa}B p65, which suggests that the NF-{kappa}B pathway is hyperactivated. Furthermore, increased level of cleaved Notch1 was detected when DN-MAML was expressed. When DN-MAML-overexpressing cells were treated with GSI, significantly decreased cell viability was observed, indicating that inhibition of Notch signaling using GSI treatment and DN-MAML expression negatively affects cell viability. Taken together, targeting Notch signaling using DN-MAML and GSI treatment may present a novel method to control cell viability in cervical cancer cells.},
doi = {10.1016/J.YEXCR.2011.05.005},
journal = {Experimental Cell Research},
issn = {0014-4827},
number = 13,
volume = 317,
place = {United States},
year = {2011},
month = {8}
}