umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Wilms' tumour 1 can suppress hTERT gene expression and telomerase activity in clear cell renal cell carcinoma via multiple pathways
Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Urology and Andrology.
Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
Show others and affiliations
2010 (English)In: British Journal of Cancer, ISSN 0007-0920, E-ISSN 1532-1827, Vol. 103, no 8, 1255-1262 p.Article in journal (Refereed) Published
Abstract [en]

BACKGROUND: Wilms' tumour 1 (WT1) gene was discovered as a tumour suppressor gene. Later findings have suggested that WT1 also can be oncogenic. This complexity is partly explained by the fact that WT1 has a number of target genes.

METHOD: WT1 and its target gene human telomerase reverse transcriptase (hTERT) were analysed in clear cell renal cell carcinoma (ccRCC). In vitro experiments were performed to examine the functional link between WT1 and hTERT by overexpression of WT1 isoforms in the ccRCC cell line, TK-10.

RESULTS: WT1 demonstrated lower RNA expression in ccRCC compared with renal cortical tissue, whereas hTERT was increased, showing a negative correlation between WT1 and hTERT (P=0.005). These findings were experimentally confirmed in vitro. The WT1 generated effect on hTERT promoter activity seemed complex, as several negative regulators of hTERT transcription, such as SMAD3, JUN (AP-1) and ETS1, were activated by WT1 overexpression. Downregulation of potential positive hTERT regulators, such as cMyc, AP-2α, AP-2γ, IRF1, NFX1 and GM-CSF, were also observed. Chromatin immunoprecipitation analysis verified WT1 binding to the hTERT, cMyc and SMAD3 promoters.

CONCLUSION: The collected data strongly indicate multiple pathways for hTERT regulation by WT1 in ccRCC.

Place, publisher, year, edition, pages
2010. Vol. 103, no 8, 1255-1262 p.
Keyword [en]
renal cell carcinoma; WT1; hTERT; telomerase activity and pathways
Identifiers
URN: urn:nbn:se:umu:diva-38095DOI: 10.1038/sj.bjc.6605878ISI: 000283542900016PubMedID: 20842112OAI: oai:DiVA.org:umu-38095DiVA: diva2:372341
Available from: 2010-11-25 Created: 2010-11-24 Last updated: 2011-01-21Bibliographically approved
In thesis
1. Signalling pathways in renal cell carcinoma with a focus on telomerase regulation
Open this publication in new window or tab >>Signalling pathways in renal cell carcinoma with a focus on telomerase regulation
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Telomerase is a ribonucleoprotein complex that catalyses telomeric repeat addition at the ends of chromosomes. The catalytic subunit, hTERT, acts as a key determinant for telomerase activity control; the induction of hTERT expression is required for telomerase activity. hTERT participates in cellular immortalization and is elevated in certain malignant tissues. Several tumours exhibit telomerase activity, which contributes to the infinite proliferation capacity that promotes tumour progression.

Renal cell carcinoma (RCC) represents 2% of all adult malignancies and has a high mortality rate. The WHO classifies RCC into several sub-types based on cytogenetic aberrations and morphological features; the most prevalent sub-types are clear cell (ccRCC), papillary (pRCC), and chromophobe RCC (chRCC). The aims of this thesis were to study the expression patterns of various signalling molecules, to elucidate the functional links among them, and to define the roles of these signalling molecules in the regulation of hTERT gene expression and telomerase activity in RCC. The first paper included in this thesis revealed mRNA overexpression of DJ-1 (a PTEN inhibitor), cMyc, and hTERT in clinical ccRCC samples compared to tumour-free kidney cortex tissues. Significant, positive correlations were detected for DJ-1, cMyc, and hTERT mRNA levels in ccRCC, but not in pRCC. In vitro knockdown of DJ-1 by siRNA in ccRCC cells induced downregulation of p-Akt, cMyc, hTERT, and telomerase activity. Forced overexpression of DJ-1 in an ovarian carcinoma cell line was followed by increased hTERT promoter activity, which appeared to be dependent on cMYC binding to the promoter. Collectively, the in vitro studies verified a functional link among DJ-1, cMyc, and hTERT as implied in the clinical ccRCC samples. The second paper included in this thesis demonstrated overexpression of NBS1 mRNA levels in ccRCC compared to the kidney cortex. NBS1 mRNA levels exhibited significant, positive correlations with DJ-1, cMyc, and S phase, but not with hTERT. In vitro experiments suggested that DJ-1 could regulate NBS1 gene expression. The role of the hTERT transcriptional repressor WT1 in RCC was evaluated in the third paper included in this thesis. ccRCC samples displayed low WT1 mRNA levels compared to kidney cortex samples. Interestingly, WT1 expression was negatively associated with hTERT and cMyc both of which were elevated in ccRCC. Forced overexpression of WT1 isoforms in a ccRCC cell line increased the expression of several negative transcriptional regulators of hTERT and diminished the expression of hTERT positive regulators. In consequence, hTERT mRNA levels and telomerase activity were reduced. Chromatin immunoprecipitation verified direct binding of WT1 to the cMyc, Smad3, and hTERT promoters. Taken together, these data suggested that in ccRCC, WT1 affects hTERT at the transcriptional level via a combined effect on both positive and negative regulators. In conclusion, DJ-1 can regulate hTERT and telomerase activity through the PI3K pathway encompassing PTEN, NBS1, p-Akt, and cMyc in ccRCC, but not in pRCC. WT1 negatively regulates hTERT and telomerase activity directly and indirectly through multiple pathways in ccRCC.

Place, publisher, year, edition, pages
Umeå: Umeå University, 2010. 74 p.
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 1391
Keyword
Renal cell carcinoma, DJ-1, NBS1, PTEN, WT1, cMyc, hTERT, telomerase
National Category
Cell and Molecular Biology
Research subject
Pathology
Identifiers
urn:nbn:se:umu:diva-38121 (URN)978-91-7459-111-8 (ISBN)
Public defence
2010-12-17, Hörsal Betula, byggnad 6M, NUS, Umeå, 09:00 (English)
Opponent
Supervisors
Available from: 2010-12-06 Created: 2010-11-25 Last updated: 2010-12-06Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Authority records BETA

Sitaram, Raviprakash TDegerman, SofieLjungberg, BörjeAndersson, EmmaRoos, GöranLi, Ai-Hong

Search in DiVA

By author/editor
Sitaram, Raviprakash TDegerman, SofieLjungberg, BörjeAndersson, EmmaRoos, GöranLi, Ai-Hong
By organisation
PathologyUrology and AndrologyClinical chemistry
In the same journal
British Journal of Cancer

Search outside of DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 280 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf