DKK4 enhances resistance to chemotherapeutics 5-Fu and YN968D1 in colorectal cancer cells.

Dickkopf-related protein 4 (DKK4) is a target of the β-catenin/transcription factor 4 complex in colorectal cancer. Previous research has demonstrated that its expression level may vary and has indicated that it may have a role in the development of resistance to chemotherapy in colorectal cancer cells. In the present study, DKK4 was over expressed in several colorectal cancer cell lines. The DKK4 over-expressing cell lines were screened using reverse transcription quantitative polymerase chain reaction analysis and western blotting. Analysis of cell viability in the control and DKK4 over-expressing cell lines, following treatment with 5-fluorouracil (5-Fu), YN968D1 or both, indicated that DKK4 over-expressing cells exhibit increased drug resistance. The results of Transwell chamber assays suggested that DKK4 had an effect on cell migration. Furthermore, the results from flow cytometric analysis showed that the percentage of apoptotic cells was reduced in the DKK4 over-expressing cell lines, following drug treatment, compared with the control. The present data suggested that DKK4 may enhance the resistance of colorectal cancer cells to 5-Fu and YN968D1 treatment, when used alone or in combination.