Discoidin domain receptor 1a (DDR1a) confers 5-fluorouracil cytotoxicity in LoVo cell via PI3K/AKT/Bcl-2 pathway

5-Fluorouracil (5-FU) is a common chemotherapy drug for patients with advanced colorectal cancer; however, many patients develop resistance to 5-FU and suffer from treatment failure. Discoidin domain receptor 1 (DDR1) is upregulated in multiple cancers and positively associated with chemoresistance. We explored the effect of DDR1a on the cytotoxicity induced by 5-FU in LoVo cells and the underlying mechanism. Therefore, DDR1a overexpression (DDR1a(high)) and knockdown in LoVo cell lines (shDDR1a) were constructed to detect cell viability and cytotoxicity induced by 5-FU. The results showed that cell viability of DDR1a(high) cells was higher in comparison with that of the control group. When 5-FU (5 µM) was administered, the percentage of apoptotic cells, cytochrome C release and caspase-3 activity was found to be higher in the shDDR1a group than that in the control group. Both of PI3K and MDM2 proteins level decreased in DDR1a(high) and shDDR1a, but the BAX/Bcl-2 level in the shDDR1a group increased compared to that in the control. Therefore, DDR1a might be a potential therapeutic target for 5-FU chemoresistance in colorectal cancer.