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High levels of SIRT1 expression enhance tumorigenesis and associate with a poor prognosis of colorectal carcinoma patients.

Chen X, Sun K, Jiao S, Cai N, Zhao X, Zou H, Xie Y, Wang Z, Zhong M, Wei L - Sci Rep (2014)

Bottom Line: We found that many CRC specimens had strong SIRT1 expression, which had an obvious correlation with poor prognosis of CRC patients.Moreover, SIRT1 deficiency decreased percentage of CD133(+) cells, attenuated the abilities of colony and sphere formation, and inhibited tumorigenicity in vivo in CRC cells.Further study demonstrated that the expressions of several stemness-associated genes, including Oct4, Nanog, Cripto, Tert and Lin28, were reduced by SIRT1 knockdown in CRC cells.

View Article: PubMed Central - PubMed

Affiliation: Central Laboratory, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.

ABSTRACT
SIRT1, a NAD(+) dependent class III deacetylase, takes part in many important biological processes. Previous studies show that SIRT1 is overexpressed in some cancers and plays an essential role in tumorigenesis. However, the association between SIRT1 and colorectal cancer (CRC) is still unclear. We found that many CRC specimens had strong SIRT1 expression, which had an obvious correlation with poor prognosis of CRC patients. Meanwhile, SIRT1 expression had a co-localization with CD133, a current universal marker to characterize colorectal cancer stem cells (CSCs). In vitro studies also revealed that SIRT1 was overexpressed in colorectal CSC-like cells. Moreover, SIRT1 deficiency decreased percentage of CD133(+) cells, attenuated the abilities of colony and sphere formation, and inhibited tumorigenicity in vivo in CRC cells. Further study demonstrated that the expressions of several stemness-associated genes, including Oct4, Nanog, Cripto, Tert and Lin28, were reduced by SIRT1 knockdown in CRC cells. Taken together, our findings suggest that SIRT1 plays a crucial role in keeping the characteristics of CSCs cells. SIRT1 is a potential independent prognostic factor of CRC patients after tumor resection with curative intent, and will contribute to providing a promising new approach to target at CSCs in CRC treatment.

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SIRT1 deficiency affects the expression of p53 and genes involved in self-renewal of SW620 cells.(A) Quantitative real time PCR analysis of p53 mRNA levels in control SW620 cells and cells transduced with shRNAs or Scr-ShRNA. (B) Western blotting of p53 and GAPDH of control SW620 cells and cells transduced with shRNAs or Scr-ShRNA. (C) Quantitative western blotting analysis of p53 protein levels in control SW620 cells and cells transduced with shRNAs or Scr-ShRNA. (D) Quantitative real time PCR analysis of the mRNA levels of stemness-associated genes (Oct4, Nanog, Cripto, Tert, Lin28, Sox2, Smo and Bmi-1) in control SW620 cells and cells transduced with shRNAs or Scr-ShRNA. All data are representative of three independent experiments. Significance: *P<0.05, **P<0.01, compared with the controls.
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f6: SIRT1 deficiency affects the expression of p53 and genes involved in self-renewal of SW620 cells.(A) Quantitative real time PCR analysis of p53 mRNA levels in control SW620 cells and cells transduced with shRNAs or Scr-ShRNA. (B) Western blotting of p53 and GAPDH of control SW620 cells and cells transduced with shRNAs or Scr-ShRNA. (C) Quantitative western blotting analysis of p53 protein levels in control SW620 cells and cells transduced with shRNAs or Scr-ShRNA. (D) Quantitative real time PCR analysis of the mRNA levels of stemness-associated genes (Oct4, Nanog, Cripto, Tert, Lin28, Sox2, Smo and Bmi-1) in control SW620 cells and cells transduced with shRNAs or Scr-ShRNA. All data are representative of three independent experiments. Significance: *P<0.05, **P<0.01, compared with the controls.

Mentions: It was reported that p53 was involved in the formation of induced pluripotent stem (iPS) cell. The suppression of p53 increased the efficiency of iPS cell generation in both mouse and human36. Meanwhile, SIRT1 down regulated p53 activation in CML37. Therefore, we detected the expression of p53 when SIRT1 was knocked down in CRC cells. The result showed that p53 expression had an increase in SW620 when SIRT1 was knocked down (Figure 6A, B and C). Then we further explore the mechanism of SIRT1 in keeping the stemness by detecting the expression of several associated genes, including Oct4, Nanog, Sox2, Bmi-1, Cripto, Tert, Smo and Lin28. Quantitative real time PCR results showed that the mRNA levels of Oct4, Nanog, Cripto, Tert and Lin28 all had apparent reductions when SIRT1 was inhibited. However, SIRT1 inhibition had no significant impact on the expressions of Sox2, Smo and Bmi-1 (Figure 6D). These results revealed that SIRT1 inhibition led to the increase of p53 expression and the decrease of several stemness-associated genes expressions in CRC cells.


High levels of SIRT1 expression enhance tumorigenesis and associate with a poor prognosis of colorectal carcinoma patients.

Chen X, Sun K, Jiao S, Cai N, Zhao X, Zou H, Xie Y, Wang Z, Zhong M, Wei L - Sci Rep (2014)

SIRT1 deficiency affects the expression of p53 and genes involved in self-renewal of SW620 cells.(A) Quantitative real time PCR analysis of p53 mRNA levels in control SW620 cells and cells transduced with shRNAs or Scr-ShRNA. (B) Western blotting of p53 and GAPDH of control SW620 cells and cells transduced with shRNAs or Scr-ShRNA. (C) Quantitative western blotting analysis of p53 protein levels in control SW620 cells and cells transduced with shRNAs or Scr-ShRNA. (D) Quantitative real time PCR analysis of the mRNA levels of stemness-associated genes (Oct4, Nanog, Cripto, Tert, Lin28, Sox2, Smo and Bmi-1) in control SW620 cells and cells transduced with shRNAs or Scr-ShRNA. All data are representative of three independent experiments. Significance: *P<0.05, **P<0.01, compared with the controls.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4265776&req=5

f6: SIRT1 deficiency affects the expression of p53 and genes involved in self-renewal of SW620 cells.(A) Quantitative real time PCR analysis of p53 mRNA levels in control SW620 cells and cells transduced with shRNAs or Scr-ShRNA. (B) Western blotting of p53 and GAPDH of control SW620 cells and cells transduced with shRNAs or Scr-ShRNA. (C) Quantitative western blotting analysis of p53 protein levels in control SW620 cells and cells transduced with shRNAs or Scr-ShRNA. (D) Quantitative real time PCR analysis of the mRNA levels of stemness-associated genes (Oct4, Nanog, Cripto, Tert, Lin28, Sox2, Smo and Bmi-1) in control SW620 cells and cells transduced with shRNAs or Scr-ShRNA. All data are representative of three independent experiments. Significance: *P<0.05, **P<0.01, compared with the controls.
Mentions: It was reported that p53 was involved in the formation of induced pluripotent stem (iPS) cell. The suppression of p53 increased the efficiency of iPS cell generation in both mouse and human36. Meanwhile, SIRT1 down regulated p53 activation in CML37. Therefore, we detected the expression of p53 when SIRT1 was knocked down in CRC cells. The result showed that p53 expression had an increase in SW620 when SIRT1 was knocked down (Figure 6A, B and C). Then we further explore the mechanism of SIRT1 in keeping the stemness by detecting the expression of several associated genes, including Oct4, Nanog, Sox2, Bmi-1, Cripto, Tert, Smo and Lin28. Quantitative real time PCR results showed that the mRNA levels of Oct4, Nanog, Cripto, Tert and Lin28 all had apparent reductions when SIRT1 was inhibited. However, SIRT1 inhibition had no significant impact on the expressions of Sox2, Smo and Bmi-1 (Figure 6D). These results revealed that SIRT1 inhibition led to the increase of p53 expression and the decrease of several stemness-associated genes expressions in CRC cells.

Bottom Line: We found that many CRC specimens had strong SIRT1 expression, which had an obvious correlation with poor prognosis of CRC patients.Moreover, SIRT1 deficiency decreased percentage of CD133(+) cells, attenuated the abilities of colony and sphere formation, and inhibited tumorigenicity in vivo in CRC cells.Further study demonstrated that the expressions of several stemness-associated genes, including Oct4, Nanog, Cripto, Tert and Lin28, were reduced by SIRT1 knockdown in CRC cells.

View Article: PubMed Central - PubMed

Affiliation: Central Laboratory, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.

ABSTRACT
SIRT1, a NAD(+) dependent class III deacetylase, takes part in many important biological processes. Previous studies show that SIRT1 is overexpressed in some cancers and plays an essential role in tumorigenesis. However, the association between SIRT1 and colorectal cancer (CRC) is still unclear. We found that many CRC specimens had strong SIRT1 expression, which had an obvious correlation with poor prognosis of CRC patients. Meanwhile, SIRT1 expression had a co-localization with CD133, a current universal marker to characterize colorectal cancer stem cells (CSCs). In vitro studies also revealed that SIRT1 was overexpressed in colorectal CSC-like cells. Moreover, SIRT1 deficiency decreased percentage of CD133(+) cells, attenuated the abilities of colony and sphere formation, and inhibited tumorigenicity in vivo in CRC cells. Further study demonstrated that the expressions of several stemness-associated genes, including Oct4, Nanog, Cripto, Tert and Lin28, were reduced by SIRT1 knockdown in CRC cells. Taken together, our findings suggest that SIRT1 plays a crucial role in keeping the characteristics of CSCs cells. SIRT1 is a potential independent prognostic factor of CRC patients after tumor resection with curative intent, and will contribute to providing a promising new approach to target at CSCs in CRC treatment.

Show MeSH
Related in: MedlinePlus