Augmented efficacy and the mechanism of a combined use of daunorubicin with rofecoxib in treatment of triple-negative breast cancer

Triple-negative breast cancer is the tumor that lacks expressions of estrogen receptor（ER）, progesterone receptor（PR） and human epidermal growth factor receptor-2（HER2）. A regular chemotherapy cannot eradicate triple-negative breast cancer. In the present study, we aimed to develop a combined use of daunorubicin and rofecoxib to treat triple-negative breast cancer, and reveal the underlying mechanisms. A gradient elution HPLC-UV method was developed for quantification, and the evaluations were performed on the triple-negative breast cancer MDA-MB-231 cells using a high content screening system. The results demonstrated that daunorubicin alone was insensitive to the triple negative breast cancer cells, while the combined use of daunorubicin and rofecoxib was able to effectively kill these triple-negative cancer cells, exhibiting a rofecoxib concentration-dependent manner. The mechanism revealed that the augmented anticancer efficacy was associated with direct killing effect, inducing apoptosis and inducing autophagy by the combination treatment. Besides, the apoptosis signaling pathways were correlated to a cascade of reactions by activating apoptotic enzyme caspase family and by suppressing anti-apoptotic gene expressed protein Bcl-2 family. In conclusion, this study provided a fundamental evidence for further developing the combined use of daunorubicin and rofecoxib formulation, hence offering a promising strategy for eradicating the triple negative breast cancer.

A novel type of functional epirubicin liposomes modified with DSPE-PEG_(2000)-cyclopamine conjugate for eliminating heterogeneous breast cancer cells

Common chemotherapy is unable to eliminate the heterogeneous side population of cancer cells （such as cancer stem-like cells）, resulting in poor prognosis. The heterogeneity of cancer cells causes an extensive multidrug resistance through the aberrantly active Hedgehog （Hh） signaling pathway. Cyclopamine is a chemical compound that can block Hh signaling pathway, and a combination use of cyclopamine with anticancer drug would be beneficial for killing heterogeneous cancer cells. In the present study, we aimed to develop a kind type of fimctional drug liposomes for eliminating heterogeneous cancer, The study was performed on human breast cancer cells. A distearoylphosphoethanolamine polyethylene glycol （DSPE-PEG2000）-cyclopamine conjugate was newly synthesized by a nucleophilic substitution reaction, and confirmed by MALDI-TOF mass. An HPLC method was established and validated for qualification of epirubicin. Functional epimbicin liposomes were successful constructed by modifying with DSPE-PEG2o00-cyclopamine, displaying a particle size in nano-scale （approximately 98 nm） and a high epirubicin encapsulation （〉97%）. The CD44＋/CD24-side population was characterized in defining heterogeneous breast cancer cells. As compared with regular epirubicin liposomes, fimctional epirubicin liposomes exhibited an evidently enhanced cellular drug uptake and a significant killing effect in overall breast cancer cells. In conclusion, the functional epirubicin liposomes could be a useful drug delivery carrier for eliminating heterogeneous breast cancer cells.

The use of a new functional glucose conjugate material, TPGS_(1000)-Glu, in treatment of brain glioma by incorporating into epirubicin liposomes

Most of antieancer agents can not be used for treatment of brain glioma due to the existence of the blood brain barrier （BBB）. The over-expression of glucose transporters （GLUTs） on the BBB and brain glioma cells enables the possibility that the GLUTs ligand modified drug carrier transports across the BBB, and targets to the brain glioma cells. The objectives of the present study were to synthesize a new glucose conjugate material, TPGS1000-Glu, develop a kind of TPGSI00o-Glu modified epirubicin liposomes, and evaluate their efficacy. The studies were performed on the BBB co-culture model and brain glioma cells in vitro. TPGS 1000-Glu was synthesized by conjugating TPGSlo00_COOH with 4-aminophenyl-[3-D-glucopyranoside （Glu）, and confirmed by MALDI-TOF-MS spectrum. TPGS^0oo-GIu modified epirubicin liposomes were prepared with a high drug encapsulation efficiency （〉97%）, a nanosize （approximately 90 nm）, and a minimal drug leakage in fetal bovine serum （FBS）-containing buffer system. The BBB co-culture model was established, and after applying TPGSl0oo-Glu modified epirubicin liposomes to the model, transport of liposomal drug across the BBB was evidenced. Besides, TPGS1000-Glu modified epirubicin liposomes showed the strongest cellular drug uptake and anti-glioma efficacy after transport across the BBB in vitro. The synthesized TPGS1000-Glu material could offer a new targeting ligand for the BBB, while the developed TPGS1000-Glu modified epirubicin liposomes might provide a potential anticancer formulation for treatment of brain glioma.