Synthesis and biological evaluation of paclitaxel and vorinostat co-prodrugs for overcoming drug resistance in cancer therapy in vitro

Paclitaxel (PTX) is the first-line treatment drug for breast cancer. However, drug resistance after a course of treatment and low selectivity restricted its clinical utility sometimes. In this study, we successfully bound PTX and vorinostat (SAHA) to form co-prodrugs based on the synergistic anticancer effects. The PTX-SAHA co-prodrugs were conjugated by glycine (1a) and succinic acid (1b) respectively and the former has shown better activity in cytotoxicity, cell cycle arrest and western-blot experiments. Therefore, 1a was further prepared to nanomicelles with mPEG(2000-)PLA(1750) as the carrier by using thin film method. PTX-SAHA co-prodrug nanomicelles were spherical with a particle size of 20-100 nm. In vitro drug release test showed 1a nanomicelles had sustained release effect, which could reduce the resistance of PTX. In vitro cytotoxicity was evaluated by SRB assay in HCT-116 cells, MCF-7 cells and drug-resistant MCF-7/ADR cells. The results showed 1a nanomicelles had comparable or even better cytotoxicity than PTX especially in the MCF-7/ADR cells. All the results suggested that PTX-SAHA co-prodrug nanomicelles were promising treatment for PTX resistance cancer.