Published online Aug 28, 2016. doi: 10.3748/wjg.v22.i32.7342
Peer-review started: April 23, 2016
First decision: May 27, 2016
Revised: June 11, 2016
Accepted: July 6, 2016
Article in press: July 6, 2016
Published online: August 28, 2016
Processing time: 122 Days and 22.8 Hours
To investigate the anticancer effect of a recombinant adenovirus-mediated p53 (rAd-p53) combined with 5-fluorouracil (5-FU) in human colon cancer resistant to 5-FU in vivo and the mechanism of rAd-p53 in reversal of 5-FU resistance.
Nude mice bearing human colon cancer SW480/5-FU (5-FU resistant) were randomly assigned to four groups (n = 25 each): control group, 5-FU group, rAd-p53 group, and rAd-p53 + 5-FU group. At 24 h, 48 h, 72 h, 120 h and 168 h after treatment, 5 mice were randomly selected from each group and sacrificed using an overdose of anesthetics. The tumors were removed and the protein expressions of p53, protein kinase C (PKC), permeability-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1) (Western blot) and apoptosis (TUNEL) were determined.
The area ratios of tumor cell apoptosis were larger in the rAd/p53 + 5-FU group than that in the control, 5-FU and rAd/p53 groups (P < 0.05), and were larger in the rAd/p53 group than that of the control group (P < 0.05) and the 5-FU group at more than 48 h (P < 0.05). The p53 expression was higher in the rAd/p53 and the rAd/p53 + 5-FU groups than that of the control and 5-FU groups (P < 0.05), and were higher in the rAd/p53 + 5-FU group than that of the rAd/p53 group (P < 0.05). Overexpression of PKC, P-gp and MRP1 was observed in the 5-FU and control groups. In the rAd/p53 + 5-FU group, the expression of P-gp and MRP1 was lower that of the control and 5-FU groups (P < 0.05), and the expression of PKC was lower than that of the control, 5-FU and rAd/p53 groups at more than 48 h (P < 0.05). In the rAd/p53 group, the expression of P-gp and MRP1 was lower that of the control and 5-FU groups at more than 48 h (P < 0.05), and the expression of PKC was lower than that of the control and 5-FU groups at more than 120 h (P < 0.05).
5-FU combined with rAd-p53 has a synergistic anticancer effect in SW480/5-FU (5-FU resistance), which contributes to reversal of 5-FU resistance.
Core tip: To observe anticancer action of a recombinant adenovirus-mediated p53 (rAd-p53) combined with 5-fluorouracil (5-FU) in human colon cancer with resistance to 5-FU in vivo to investigate the potential and mechanism of rAd-p53 in the reversal of resistance to 5-FU in human colon cancer. Our previous results revealed that exogenous wild-type p53 gene from rAd-p53 can decrease expression of PKC, P-gp and MRP1 in SW480/5-FU (5-FU resistance) and promote apoptosis of tumor cell, which contributes to reversing 5-FU resistance in vivo. 5-FU can increase the expression of exogenous wild-type p53, so 5-FU combined with rAd-p53 has a synergistic anticancer effect for colon cancer of 5-FU resistance in vivo.