Abstract
Background/Aim: Trifluridine/tipiracil (FTD/TPI) is used for metastatic colorectal cancer, that is refractory to 5-fluorouracil (5-FU)-based therapies. However, the impact of pre-exposure to 5-FU on the anti-cancer effect of FTD, which is a key component of FTD/TPI, is unclear. Materials and Methods: The incorporation into DNA and anti-cancer activity of FTD were analyzed in several cancer cell lines under response to FTD treatment with or without 5-FU pre-exposure. The volumes of tumors in xenografted nude mice were examined among groups that were either untreated or treated with S-1, FTD/TPI or FTD/TPI with pre-exposure to S-1. Results: Pre-exposure to 5-FU significantly increased FTD incorporation into DNA and enhanced its anti-cancer effect for viability and proliferation of cancer cells. In the xenograft nude mouse model, the tumor volumes in the FTD/TPI-treated and S-1-pre-exposed group were lower than those in the FTD/TPI-only-treated group. Although both FTD dose and exposure time in the FTD/TPI-treated and S-1-pre-exposed mice were smaller than those in the FTD/TPI-only-treated mice, the incorporated FTD in the tumors in the former group was 86.5% of that in the latter group. Conclusion: Pre-exposure to 5-FU enhanced the incorporation into DNA and the anti-cancer effect of FTD in the context of colorectal cancer. Our data indicate the potential for a new sequential therapy using S-1 and FTD/TPI to improve prognosis of colorectal cancer.
Footnotes
Conflicts of Interest
This study was funded by Taiho Pharmaceutical Co. Ltd. (Tokyo, Japan). The sponsor had no role in the study design, study performance, data collection, management and interpretation, or preparation or approval of the article.
- Received December 13, 2017.
- Revision received January 21, 2018.
- Accepted January 23, 2018.
- Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved