Complete regression of xenografted breast tumors by dextran-based dual drug conjugates containing paclitaxel and docosahexaenoic acid

In this study, a novel carboxymethyl dextran (CMD)-based dual drug delivery system that delivering two water insoluble drugs to tumor sites was developed and evaluated for anticancer activities. Paclitaxel (PTX) and docosahexaenoic acid (DHA) were covalently coupled with CMD to generate CMD-DHA-PTX conjugate S and conjugate L with different linkers containing amino acids Gly-Gly or Lys-Gly-Gly, respectively. Both conjugates possessed high PTX loading contents and enhanced water solubility, as well as the ability of being self-assembled into nanoparticles with the nanoparticle size ranged from 88.7 nm to 94.7 nm. These two conjugates released free PTX continuously in plasma and cancer cells. The conjugate S exhibited improved pharmacokinetic parameters and higher distribution extent in tumor sites than the parent PTX, Abraxane and the conjugate L. The antitumor efficacy of these two conjugates outperformed parent PTX formulation and Abraxane in nude mice bearing breast cancer cells MCF-7. More importantly, the conjugate S treatment eliminated all the xenograft tumors without causing any mice body weight loss in mice model. This study revealed that the dextran-based dual drug conjugates may represent an effective and innovative way to deliver anticancer agents to a variety of tumors.