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Agbo et al. J Cancer Metastasis Treat 2019;5:x I http://dx.doi.org/10.20517/2394-4722.2019.35 Page 9 of 11

shown to regulate apical-basolateral polarity in intestinal epithelial cells and to enhance their polarity
[13]
by transcriptional regulation . Thus, loss of KLF4 expression during development and progression of
CRC may lead to loss of cell polarity with progression toward EMT. Furthermore, it has been previously
demonstrated that E-cadherin (Cdh1), N-cadherin (Cdh2), vimentin (Vim), and β-catenin (Ctnnb1) genes
[30]
are direct transcriptional targets of KLF4 . Yori et al. [29,41] demonstrated that KLF4 is necessary for
the maintenance of E-cadherin expression, repression of SNAI1, and prevention of EMT in mammary
epithelial cells. These results are consistent with our observations. We demonstrated a positive correlation
between KLF4 and E-cadherin and a negative one between KLF4 and N-cadherin and vimentin in human
and mouse tissues. However, we were not able to show increased nuclear levels of β-catenin in mouse
[18]
tissues after AOM/DSS treatment . This could be due to technical differences, as we previously used
immunohistochemical staining and the current analysis was based on immunofluorescence studies. In
addition, we showed that KLF4 expression is negatively correlated to the expression of TWIST, SNAI2,
and claudin-1. Taken together, these results suggest that KLF4 may regulate EMT at several different stages
of CRC progression, including suppression of expression of transcription factors (TWIST and SNAI2),
transcriptional co-activator (β-catenin), and regulation of cell polarity (E-cadherin, N-cadherin, and
claudin-1). In conclusion, we showed a negative association between KLF4 and mesenchymal EMT markers
in both human and mouse CRC tissues. Future studies are necessary to identify the mechanism by which
KLF4 regulates EMT progression in CRC.

DECLARATIONS
Acknowledgments
We thank the Department of Pathology at Stony Brook University for technical assistance in
histopathological analysis.

Authors’ contributions
Made substantial contributions to conception and design of the study and performed data analysis and
interpretation: Yang VW, Ghaleb AM, Bialkowska AB
Performed data acquisition and analyzed data: Agbo KC, Huang JZ, Ghaleb AM
Provided tissues samples: Williams JL
Provided assistance with histopathological analysis: Shroyer KR

Availability of data and materials
Not applicable.

Financial support and sponsorship
This work was supported by grants from the National Institutes of Health awarded to Yang VW (CA084197).

Conflicts of interest
All authors declared that there are no conflicts of interest.

Ethical approval and consent to participate
The protocol for the sample collection was originally approved by the Institutional Review Board by the
State University of New York at Stony Brook on October 17th, 2014 (CORIHS 2014-2821-F) and qualified
for a waiver under the Federal Law of Department of Health and Human Services per article 45CFR46.116.d.

Consent for publication
Not applicable.