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Activin A induces SLC5A8 expression through the Smad3 signaling pathway in human colon cancer RKO cells

Yu Zhang1, Yong-Li Bao, Mei-Ting Yang

  • 1National Engineering Laboratory for Druggable Gene and Protein Screening, Northeast Normal University, Changchun 130024, China.

The International Journal of Biochemistry & Cell Biology
|August 25, 2010
PubMed

Insights

Activin A up-regulates the tumor suppressor gene SLC5A8 in colorectal cancer cells via the Smad signaling pathway. This mechanism contributes to Activin A

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Cell Signaling

Background:

  • Solute carrier family 5, member 8 (SLC5A8) is a potential tumor suppressor gene implicated in colorectal cancer.
  • Epigenetic changes down-regulate SLC5A8 in some colorectal cancers, and its re-expression inhibits cancer cell proliferation.
  • Activin A, a TGF-β superfamily member, inhibits tumor cell proliferation, but its mechanisms remain unclear.

Purpose of the Study:

  • To investigate the effect of Activin A on SLC5A8 expression in colorectal cancer cells.
  • To elucidate the signaling pathway and transcriptional mechanisms underlying Activin A-induced SLC5A8 regulation.
  • To understand how Activin A's effects on SLC5A8 contribute to its tumor-inhibitory functions.

Main Methods:

  • Utilized colorectal cancer RKO cells and human embryonic kidney (HEK) 293T cells.
  • Investigated Smad signaling pathway activation, including the use of dominant-negative Smad3 and Smad2.
  • Performed transcriptional activation assays and promoter deletion analysis of the human SLC5A8 gene.

Main Results:

  • Activin A significantly up-regulated SLC5A8 expression in both RKO and HEK 293T cells.
  • Activin A-induced SLC5A8 expression was dependent on Smad3 activation.
  • Activin A mediated SLC5A8 expression via transcriptional activation, involving the CAGA elements in the -273/-222 promoter region.

Conclusions:

  • Activin A up-regulates SLC5A8 expression through the Smad signaling pathway in colorectal cancer cells.
  • This up-regulation mechanism partially explains the tumor-suppressive effects of Activin A.
  • Findings highlight a novel molecular link between Activin A signaling and SLC5A8 in cancer.

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