Development of Stealth Liposome Formulation of 2′-Deoxyinosine as 5-Fluorouracil Modulator: In Vitro and In Vivo Study
The aims of this study were to develop a stealth, pegylated liposomal formulation of 2′-deoxyinosine (d-Ino), a 5-fluorouracil (5-FU) modulator, to evaluate its efficacy in vitro and in tumor-bearing mice, and to study its pharmacokinetics in rats.
After designing a pegylated liposome encapsulating d-Ino (L-d-Ino), we evaluated its efficacy as 5-FU modulator in vitro. Antiproliferative assays, thymidylate synthase (TS) inhibition, and apoptosis studies were carried out to check whether an optimization of 5-FU action was achieved on the 5-FU-resistant SW620 cell line. Animal pharmacokinetic and ex vivo studies were next performed to confirm that L-d-Ino displayed a slower plasma elimination pattern than free d-Ino. Finally, effects on tumor growth of L-d-Ino + 5-FU combination was evaluated in xenografted mice.
We developed a stable, sterile, and homogenous 100-nm population of pegylated liposomes encapsulating 30% of d-Ino. Liposomal d-Ino exhibited a strong potential as 5-FU modulator in vitro by enhancing TS inhibition and subsequent apoptosis induction, while displaying a better pharmacokinetic profile in animals, with a near seven times clearance reduction as compared with the free form. When used in tumor-bearing mice in combination with 5-FU, our results showed next that the association led to 70% of tumor reduction with a doubling median survival time as compared with untreated animals, whereas 5-FU alone was ineffective.
Our data show that liposomal d-Ino, through an optimized pharmacokinetic profile, displays apotenteffect as fluoropyrimidines modulator, both in vitro and in xenografted mice. Besides, we showed here that itispossible to reverse a resistant phenotype to 5-FU, a major drug extensively described in clinical oncology.
Key Words2′-deoxyinosine 5-FU liposome pharmacokinetics thymidylate synthase xenografts
- 1.Cohen, A. M., Minsky, B. D., Schilsky, R. L. 1993Colon cancer. InDevita, V.T.Hellman, S.Rosenberg, S. A. eds. Cancer, Principles and Practises of Oncology4th edn.JB LippincottPhiladelphia929977Google Scholar
- 4.Inaba, M., Mistsuhashi, J., Sawada, H., Miike, N., et al. 1996Reduced activity of anabolizing enzymes in 5-fluorouracil-resistant human stomach cancer cellsJpn. Cancer Res.87212220Google Scholar
- 11.Ciccolini, J., Cuq, P., Evrad, A., Giacometti, S., Pelegrin, A., Aubert, C., Cano, J. P., Iliadis, A. 2001Combination of thymidine phosphorylase gene transfer and deoxyinosine treatment greatly enhances 5-fluorouracil antitumor activity in vitro and in vivo Mol. Cancer Ther.1133139PubMedGoogle Scholar
- 19.Rustum, Y. M. 1999Clinical implications of 5-FU modulationOncology (Huntingt.)132225Google Scholar
- 22.Schwartz, E. L., Baptiste, N., O'Connor, C. J., Wadler, S., et al. 1994Potentiation of the antitumor activity of 5-fluorouracil in colon carcinoma cells by the combination of interferon and deoxyribonucleosides results from complementary effects on thymidine phosphorylaseCancer Res.5414721478PubMedGoogle Scholar
- 30.Hong, R. L., Huang, C. J., Tseng, Y. L., Pang, V. F., Chen, S. T., Liu, J. J., Chang, F. H. 1999Direct comparison of liposomal doxorubicin with or without polyethylene glycol coating in C-26 tumor-bearing mice: is surface coating with polyethylene glycol beneficial?Clin. Cancer Res.536453652PubMedGoogle Scholar
- 33.Canman, C. E., Tang, H. Y., Normolle, D. P., Lawrence, T. S., et al. 1992Variations in patterns of DNA damage induced in human colorectal tumor cells by 5-fluorodeoxyuridine: implications for mechanisms of resistance and cytotoxicityProc. Natl. Acad. Sci. USA.891047410478PubMedCrossRefGoogle Scholar