A comparison study of the cytotoxicity of salinomycin and salinomycin sodium toward human breast cancer stem cells as well as breast cancer cells

Salinomycin（SAL）,a polyether antibiotic isolated from Streptomyces albus,is widely used as an anticoccidial drug in poultry and other livestock and is furthermore fed to ruminescent animals to improve nutrient absorption and feed efficiency.It has recently been shown to act as a specific inhibitor of cancer stem cells.At present,the price of salinomycin sodium（SAL-Na） is 10 fold lower than that of salinomycin,however,there is no report about the comparison of the inhibitory effects of SAL and SAL-Na on cancer stem cells as well as cancer cells.In the present study,side population cells（SP cells）and non-SP cells （NSP cells）sorted from human breast cancer cell line MCF-7 were chosen as the models of cancer stem cells and cancer cells, respectively.SRB assay was performed to compare the cytotoxicity of SAL and SAL-Na.First of all,SP cells were sorted from MCF-7 cells via FACSDiva flow cytometry.Secondly,the sorted SP cells were identified with the surface makers（CD44~＋/CD24^-） of breast cancer stem cells.Finally,the inhibitory effects of SAL and SAL-Na were evaluated on the sorted SP cells and NSP cells.Results showed that,as compared to breast cancer cells,the inhibitory effect of free SAL or free SAL-Na was more potent in breast cancer stem cells.Furthermore,the inhibitory effects of free SAL and free SAL-Na had no significant difference for the SP cells as well as the NSP cells when they were in the same concentration.Thus,it suggested that salinomycin sodium should be considered as a potential candidate to take the place of salinomycin in cancer stem cells research,due to their similar inhibitory effects on cancer stem cells.

Efficacy and mechanism of a compound epirubicin plus quinine injection for the treatment of drug--resistant breast cancer

A single drug chemotherapy fails to eliminate residual cancer cells due to the existence of the multidrug resistance （MDR）. In the present study, we aimed to develop a compound epirubicin plus quinine injection, to characterize the efficacy in treatment of the drug-resistant breast cancer, and to reveal the involved mechanisms. The HPLC-UV methods were developed for quantifications, and the evaluations were performed on the drug-resistant human breast cancer MCF-7/adr cells using a high content screening system. Results demonstrated that the compound epirubicin plus quinine injection was able to effectively block the drug efflux, exhibiting an evidently overall efficacy in treatment of the resistant breast cancer cells by direct killing effect and by apoptosis-inducing effect. In the formulation, quinine played multiple roles in blocking drug efflux and in inducing the apoptosis of the resistant breast cancer cells. The apoptosis signaling pathways were associated with a cascade of reactions by activating Caspase family and by inhibiting Bcl-2 family. In conclusion, the present study preliminarily revealed the efficacy and mechanism of the compound epirubicin plus quinine formulation in treatment of the drug-resistant breast cancer, and offered a potential strategy to overcome drug resistance in cancer treatments.

Octreotide modified PEGylated liposomes improved the anticancer efficacy of doxorubicin in somatostatin receptor II positive tumor model

Active targeting drug delivery systems （TDDS）, which could improve drug therapeutic efficacy and reduce toxicity, are still the focus of many scientific researches in cancer therapy. The drug circulation time and tumor accumulation could be significantly increased with the application of sterically stabilized liposome （SSL）. SSL could also be modified easily with certain ligands to achieve targeting drug delivery. Because many tumors overexpress somatostatin receptors （SSTRs）, octreotide （OCT） becomes a potential targeting ligand due to its high affinity to SSTRs, especially to subtype 2 （SSTR2）. In this study, OCT was conjugated to methoxypolyethyleneglycol-distearoyl-phosphatidylethanolamine （DSPE-PEG2000）, and doxorubicin （DOX）-loaded SSL with a variable percentage of octreotide-methoxypolyethyleneglycol-distearoyl-phosphatidylethanolamine （DSPE-PEG/00o-OCT） were prepared （OCT-SSL-DOX）. All liposomes were about 90 nm in diameter and negatively charged on the surface, with DOX encapsulation efficiency at above 95%. OCT modification exhibited little effect on the physicochemical properties of SSL. In this study, cellular delivery efficacy of all prepared liposomes was evaluated in SSTIL2-positive cells in vitro by flow cytometry for the optimization of the OCT density on the surface of liposomes. Lipid formulation containing 1.5% DSPE-PEG20oo-OCT exhibited the highest efficiency of intracellular drug delivery. The modification of OCT did not alter the release behaviors of liposomal DOX in vitro, but OCT-SSL-DOX increased the cytotoxicity and improved the anti-tumor effect of liposomal DOX in SST1L2- positive cells and tumor-bearing mice models. In summary, OCT-modified SSL succeeded in increasing intracellular delivery and enhancing therapeutic efficacy of encapsulated anticancer agent, suggesting that it might be a promising TDDS for the treatment of SSTR2-overexpressing cancers.

Development of ciclesonide dry powder inhalers and the anti-asthmatic efficacy in guinea pigs

Ciclesonide is a new corticosteroid currently in clinical development for the treatment of asthma by oral inhalation. The objectives of the present study were to develop ciclesonide dry powder inhalers （DPIs, 80 μg） and investigate the anti-asthmatic effect in animals. For preparing a ciclesonide capsule-type DPI, sphere-shaped lactose was used as a diluent carrier, mixed with micronized ciclesonide, and filled into a capsule, and then put into a dry powder inhaler for oral inhalation. The asthmatic model was established with guinea pigs, and the therapeutic efficacy of ciclesonide was performed on the asthmatic guinea pig model. Results showed that the pulmonary deposition ratio of ciclesonide DPIs was approximately 26% and their content uniformity met the requirements of China Pharmacopoeia. The established pathological model exhibited the typical features of asthma with a widened pulmonary alveolar interval, narrowed alveolar space and detached bronchial mucosal epithelium with topical necrosis, goblet cell hyperplasia, and inflammatory cell infiltration. After treating with ciclesonide, the impaired indicators in asthmatic guinea pigs were significantly recovered or alleviated, exhibiting decreased total cells, decreased eosinophils and a decreased IL-5 level while there was an increased IFN-γ level in the bronchoalveolar lavage fluid （BALF）. This study develops a new pulmonary ciclesonide delivery system for treating asthma, and proves the therapeutic efficacy in asthmatic guinea pigs.