PLoS ONE (Jan 2018)

The effect of S100A6 on nuclear translocation of CacyBP/SIP in colon cancer cells.

  • Shanshan Feng,
  • Qiaozhi Zhou,
  • Bo Yang,
  • Qianqian Li,
  • Aiqin Liu,
  • Yingying Zhao,
  • Changqing Qiu,
  • Jun Ge,
  • Huihong Zhai

DOI
https://doi.org/10.1371/journal.pone.0192208
Journal volume & issue
Vol. 13, no. 3
p. e0192208

Abstract

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Calcyclin Binding Protein/(Siah-1 interacting protein) (CacyBP/SIP) acts as an oncogene in colorectal cancer. The nuclear accumulation of CacyBP/SIP has been linked to the proliferation of cancer cells. It has been reported that intracellular Ca2+ induces the nuclear translocation of CacyBP/SIP. However, the molecular mechanism of CacyBP/SIP nuclear translocation has yet to be elucidated. The purpose of this study was to test whether the Ca2+-dependent binding partner S100 protein is involved in CacyBP/SIP nuclear translocation in colon cancer SW480 cells.The subcellular localization of endogenous CacyBP/SIP was observed following the stimulation of ionomycin or BAPTA/AM by immunofluorescence staining in SW480 cells. S100A6 small interfering RNAs (siRNA) were transfected into SW480 cells. Immunoprecipitation assays detected whether S100 protein is relevant to the nuclear translocation of CacyBP/SIP in response to changes in [Ca2+]i.We observed that endogenous CacyBP/SIP is translocated from the cytosol to the nucleus following the elevation of [Ca2+]i by ionomycin in SW480 cells. Co-immunoprecipitation experiments showed that the interaction between S100A6 and CacyBP/SIP was increased simultaneously with elevated Ca2+. Knockdown of S100A6 abolished the Ca2+ effect on the subcellular translocation of CacyBP/SIP.Thus, we demonstrated that S100A6 is required for the Ca2+-dependent nuclear translocation of CacyBP/SIP in colon cancer SW480 cells.