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Kaiso depletion attenuates transforming growth factor-β signaling and metastatic activity of triple-negative breast cancer cells.

Bassey-Archibong BI, Kwiecien JM, Milosavljevic SB, Hallett RM, Rayner LG, Erb MJ, Crawford-Brown CJ, Stephenson KB, Bédard PA, Hassell JA, Daniel JM - Oncogenesis (2016)

Bottom Line: Notably, Kaiso expression is induced by the TGFβ pathway and silencing Kaiso expression in the highly invasive breast cancer cell lines, MDA-MB-231 (hereafter MDA-231) and Hs578T, attenuated the expression of several EMT-associated proteins (Vimentin, Slug and ZEB1), abrogated TGFβ signaling and TGFβ-dependent EMT.Although high Kaiso and high TGFβR1 expression is associated with poor overall survival in breast cancer patients, overexpression of a kinase-active TGFβR1 in the Kaiso-depleted cells was insufficient to restore the metastatic potential of these cells, suggesting that Kaiso is a key downstream component of TGFβ-mediated pro-metastatic responses.Collectively, these findings suggest a critical role for Kaiso in TGFβ signaling and the metastasis of TNBCs.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, McMaster University, Hamilton, Ontario, Canada.

ABSTRACT
Triple-negative breast cancers (TNBCs) represent a subset of breast tumors that are highly aggressive and metastatic, and are responsible for a disproportionate number of breast cancer-related deaths. Several studies have postulated a role for the epithelial-to-mesenchymal transition (EMT) program in the increased aggressiveness and metastatic propensity of TNBCs. Although EMT is essential for early vertebrate development and wound healing, it is frequently co-opted by cancer cells during tumorigenesis. One prominent signaling pathway involved in EMT is the transforming growth factor-β (TGFβ) pathway. In this study, we report that the novel POZ-ZF transcription factor Kaiso is highly expressed in TNBCs and correlates with a shorter metastasis-free survival. Notably, Kaiso expression is induced by the TGFβ pathway and silencing Kaiso expression in the highly invasive breast cancer cell lines, MDA-MB-231 (hereafter MDA-231) and Hs578T, attenuated the expression of several EMT-associated proteins (Vimentin, Slug and ZEB1), abrogated TGFβ signaling and TGFβ-dependent EMT. Moreover, Kaiso depletion attenuated the metastasis of TNBC cells (MDA-231 and Hs578T) in a mouse model. Although high Kaiso and high TGFβR1 expression is associated with poor overall survival in breast cancer patients, overexpression of a kinase-active TGFβR1 in the Kaiso-depleted cells was insufficient to restore the metastatic potential of these cells, suggesting that Kaiso is a key downstream component of TGFβ-mediated pro-metastatic responses. Collectively, these findings suggest a critical role for Kaiso in TGFβ signaling and the metastasis of TNBCs.

No MeSH data available.


Related in: MedlinePlus

Kaiso expression positively correlates with TGFβ signaling components in triple-negative tumors. (a) Heat map showing the positive correlation between Kaiso expression and TGFβ signaling proteins. (b, c) Kaiso depletion attenuates TGFβR1 and TGFβR2 transcript and protein levels, as assessed by quantitative RT–PCR and immunoblot analysis, that is rescued upon re-expression of a sh-resistant Kaiso cDNA (d). β-Actin serves as a loading control. *P<0.05, **P<0.005.
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fig3: Kaiso expression positively correlates with TGFβ signaling components in triple-negative tumors. (a) Heat map showing the positive correlation between Kaiso expression and TGFβ signaling proteins. (b, c) Kaiso depletion attenuates TGFβR1 and TGFβR2 transcript and protein levels, as assessed by quantitative RT–PCR and immunoblot analysis, that is rescued upon re-expression of a sh-resistant Kaiso cDNA (d). β-Actin serves as a loading control. *P<0.05, **P<0.005.

Mentions: To successfully undergo metastasis, tumor cells must activate various cellular processes in addition to EMT, to enable their extravasation, survival in the circulatory system and establishment at secondary sites.34 To elucidate how Kaiso might potentiate the complete metastatic cascade, we analyzed the TCGA BCa dataset to correlate Kaiso expression with other genes implicated in tumor progression and metastasis. We found that high Kaiso expression positively correlates with several TGFβ signaling genes including Smad2, Smad4 and TGFβR1 (Figure 3a). Examination of the expression levels of various TGFβ signaling components in Kaiso-depleted TNBC cells revealed that silencing Kaiso attenuated the expression of TGFβR1 and TGFβR2 at both the transcript and protein levels in both cell lines (Figures 3b and c). However, there were no significant changes in Smad2 or Smad4 expression in either cell line (data not shown). Notably, TGFβR1 and TGFβR2 expression was upregulated following expression of a sh-resistant Kaiso form in Kaiso-depleted MDA-231 cells (Figure 3d).


Kaiso depletion attenuates transforming growth factor-β signaling and metastatic activity of triple-negative breast cancer cells.

Bassey-Archibong BI, Kwiecien JM, Milosavljevic SB, Hallett RM, Rayner LG, Erb MJ, Crawford-Brown CJ, Stephenson KB, Bédard PA, Hassell JA, Daniel JM - Oncogenesis (2016)

Kaiso expression positively correlates with TGFβ signaling components in triple-negative tumors. (a) Heat map showing the positive correlation between Kaiso expression and TGFβ signaling proteins. (b, c) Kaiso depletion attenuates TGFβR1 and TGFβR2 transcript and protein levels, as assessed by quantitative RT–PCR and immunoblot analysis, that is rescued upon re-expression of a sh-resistant Kaiso cDNA (d). β-Actin serves as a loading control. *P<0.05, **P<0.005.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4815049&req=5

fig3: Kaiso expression positively correlates with TGFβ signaling components in triple-negative tumors. (a) Heat map showing the positive correlation between Kaiso expression and TGFβ signaling proteins. (b, c) Kaiso depletion attenuates TGFβR1 and TGFβR2 transcript and protein levels, as assessed by quantitative RT–PCR and immunoblot analysis, that is rescued upon re-expression of a sh-resistant Kaiso cDNA (d). β-Actin serves as a loading control. *P<0.05, **P<0.005.
Mentions: To successfully undergo metastasis, tumor cells must activate various cellular processes in addition to EMT, to enable their extravasation, survival in the circulatory system and establishment at secondary sites.34 To elucidate how Kaiso might potentiate the complete metastatic cascade, we analyzed the TCGA BCa dataset to correlate Kaiso expression with other genes implicated in tumor progression and metastasis. We found that high Kaiso expression positively correlates with several TGFβ signaling genes including Smad2, Smad4 and TGFβR1 (Figure 3a). Examination of the expression levels of various TGFβ signaling components in Kaiso-depleted TNBC cells revealed that silencing Kaiso attenuated the expression of TGFβR1 and TGFβR2 at both the transcript and protein levels in both cell lines (Figures 3b and c). However, there were no significant changes in Smad2 or Smad4 expression in either cell line (data not shown). Notably, TGFβR1 and TGFβR2 expression was upregulated following expression of a sh-resistant Kaiso form in Kaiso-depleted MDA-231 cells (Figure 3d).

Bottom Line: Notably, Kaiso expression is induced by the TGFβ pathway and silencing Kaiso expression in the highly invasive breast cancer cell lines, MDA-MB-231 (hereafter MDA-231) and Hs578T, attenuated the expression of several EMT-associated proteins (Vimentin, Slug and ZEB1), abrogated TGFβ signaling and TGFβ-dependent EMT.Although high Kaiso and high TGFβR1 expression is associated with poor overall survival in breast cancer patients, overexpression of a kinase-active TGFβR1 in the Kaiso-depleted cells was insufficient to restore the metastatic potential of these cells, suggesting that Kaiso is a key downstream component of TGFβ-mediated pro-metastatic responses.Collectively, these findings suggest a critical role for Kaiso in TGFβ signaling and the metastasis of TNBCs.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, McMaster University, Hamilton, Ontario, Canada.

ABSTRACT
Triple-negative breast cancers (TNBCs) represent a subset of breast tumors that are highly aggressive and metastatic, and are responsible for a disproportionate number of breast cancer-related deaths. Several studies have postulated a role for the epithelial-to-mesenchymal transition (EMT) program in the increased aggressiveness and metastatic propensity of TNBCs. Although EMT is essential for early vertebrate development and wound healing, it is frequently co-opted by cancer cells during tumorigenesis. One prominent signaling pathway involved in EMT is the transforming growth factor-β (TGFβ) pathway. In this study, we report that the novel POZ-ZF transcription factor Kaiso is highly expressed in TNBCs and correlates with a shorter metastasis-free survival. Notably, Kaiso expression is induced by the TGFβ pathway and silencing Kaiso expression in the highly invasive breast cancer cell lines, MDA-MB-231 (hereafter MDA-231) and Hs578T, attenuated the expression of several EMT-associated proteins (Vimentin, Slug and ZEB1), abrogated TGFβ signaling and TGFβ-dependent EMT. Moreover, Kaiso depletion attenuated the metastasis of TNBC cells (MDA-231 and Hs578T) in a mouse model. Although high Kaiso and high TGFβR1 expression is associated with poor overall survival in breast cancer patients, overexpression of a kinase-active TGFβR1 in the Kaiso-depleted cells was insufficient to restore the metastatic potential of these cells, suggesting that Kaiso is a key downstream component of TGFβ-mediated pro-metastatic responses. Collectively, these findings suggest a critical role for Kaiso in TGFβ signaling and the metastasis of TNBCs.

No MeSH data available.


Related in: MedlinePlus