Background:
Colon cancer is a leading cause of cancer related death. Colon cancer arises due to uncontrolled cell proliferation, failure of cells to undergo apoptosis and loss of cellular differentiation. While the pathways which drive the uncontrolled proliferation of colon cancer cells are relatively well understood, the mechanistic basis for loss of cell differentiation is less well characterized. The EHF transcription factor was identified as significantly differentially expressed between well and poorly differentiated colon cancer cell lines.
Methods:
Affymetrix microarrays were used to identify transcription factors which are significantly differentially expressed between well differentiated and poorly differentiated colon cancer cell lines. Differential gene expression was confirmed by q-RT-PCR and western blot. The well differentiated colon cancer cell line SW948 was transfected with EHF targeting siRNAs using lipofectamine. Apoptosis was determined by PI staining and FACS analysis and cell proliferation determined by MTS assay.
Results:
Microarray analysis of well and poorly differentiated colon cancer cell lines identified the EHF transcription factor to be significantly downregulated in expression in poorly differentiated cell lines which was validated by Q-RT-PCR and western blot. Knockdown of EHF in the well differentiated colon cancer cell line SW948, reduced expression of differentiation markers villin and KRT20 by 82% and 64% respectively. Knockdown of EHF also reduces expression of Cdx1 suggesting it may be act upstream of this known differentiation regulator. Conversely, EHF knockdown had no effect on cell proliferation or apoptosis.
Conclusion:
We found that the EHF transcription factor is a novel regulator of cell differentiation in colon cancer.