AIE/FRET-based versatile PEG-Pep-TPE/DOX nanoparticles for cancer therapy and real-time drug release monitoring.

On account of the biological significance of self-assembling peptides in blocking the cellular mass exchange as well as impeding the formation for actin filaments resulting in program cell death, stimuli-responsive polypeptide nanoparticles have attracted more and more attention. In this work, we successfully fabricated doxorubicin-loaded polyethylene glycol-block-peptide (FFKY)-block-tetraphenylethylene (PEG-Pep-TPE/DOX) nanoparticles, where the aggregation-induced emission luminogens (AIEgen, TPE-CHO) can become a fluorescence resonance energy transfer (FRET) pair with the entrapped antitumor drug DOX to detect the release of drugs dynamically. This is the first successful attempt to detect and quantify the change of FRET signals in A549 cells via three methods to monitor the cellular uptake of nanoprobes and intracellular drug molecule release intuitively. As we proposed here, the combination of free DOX and the self-assembling peptide could achieve the synergistic anticancer efficacy. The multifunctional PEG-Pep-TPE/DOX nanoparticles may provide a new opportunity for combination cancer therapy and real-time detection of the drug release from stimuli-responsive nanomedicine.

Chemosensitization and radiosensitization of a lung cancer cell line A549 induced by a composite polymer micelle.

Multidrug resistance (MDR) to Doxorubicin (DOX) remains a major obstacle to successful cancer treatment. The present study sought to overcome the MDR of lung cancer cells and achieve radiosensitization by developing a composite DOX-loaded micelle (M-DOX). M-DOX containing PEG-PCL/Pluronic P105 was prepared by the solvent evaporation method. Lung cancer cell line A549 was adopted in this study. In vitro cytotoxicity, cellular uptake behavior, subcellular distribution, and radiosensitivity were evaluated by the treatment with M-DOX, and free DOX was used as a control. A549 cells treated with M-DOX as opposed to free DOX showed greater cellular uptake as well as greater cytotoxicity. Furthermore, M-DOX reached the mitochondria and lysosome effectively after cellular uptake, and fluorescence used to track M-DOX was found to be surrounding the nucleus. Finally, colony-forming assays demonstrated that M-DOX treatment improved radiosensitization when compared to free DOX. Based on the increased cytotoxicity and radiosensitization, M-DOX could be considered as a promising drug delivery system to overcome MDR in lung cancer therapy.

Doxorubicin-mediated radiosensitivity in multicellular spheroids from a lung cancer cell line is enhanced by composite micelle encapsulation.

BACKGROUND: The purpose of this study is to evaluate the efficacy of composite doxorubicinloaded micelles for enhancing doxorubicin radiosensitivity in multicellular spheroids from a non-small cell lung cancer cell line. METHODS: A novel composite doxorubicin-loaded micelle consisting of polyethylene glycolpolycaprolactone/Pluronic P105 was developed, and carrier-mediated doxorubicin accumulation and release from multicellular spheroids was evaluated. We used confocal laser scanning microscopy and flow cytometry to study the accumulation and efflux of doxorubicin from A549 multicellular spheroids. Doxorubicin radiosensitization and the combined effects of irradiation and doxorubicin on cell migration and proliferation were compared for the different doxorubicin delivery systems. RESULTS: Confocal laser scanning microscopy and quantitative flow cytometry studies both verified that, for equivalent doxorubicin concentrations, composite doxorubicin-loaded micelles significantly enhanced cellular doxorubicin accumulation and inhibited doxorubicin release. Colony-forming assays demonstrated that composite doxorubicin-loaded micelles are radiosensitive, as shown by significantly reduced survival of cells treated by radiation + composite micelles compared with those treated with radiation + free doxorubicin or radiation alone. The multicellular spheroid migration area and growth ability verified higher radiosensitivity for the composite micelles loaded with doxorubicin than for free doxorubicin. CONCLUSION: Our composite doxorubicin-loaded micelle was demonstrated to have radiosensitization. Doxorubicin loading in the composite micelles significantly increased its cellular uptake, improved drug retention, and enhanced its antitumor effect relative to free doxorubicin, thereby providing a novel approach for treatment of cancer.

Doxorubicin-loaded PEG-PCL copolymer micelles enhance cytotoxicity and intracellular accumulation of doxorubicin in adriamycin-resistant tumor cells.

BACKGROUND: Multidrug resistance remains a major obstacle to successful cancer chemotherapy. Some chemical multidrug resistance inhibitors, such as ciclosporin and verapamil, have been reported to reverse resistance in tumor cells. However, the accompanying side effects have limited their clinical application. In this study, we have developed a novel drug delivery system, ie, a polyethyleneglycol-polycaprolactone (PEG-PCL) copolymer micelle encapsulating doxorubicin, in order to circumvent drug resistance in adriamycin-resistant K562 tumor cells. METHODS: Doxorubicin-loaded diblock copolymer PEG-PCL micelles were developed, and the physicochemical properties of these micelles, and accumulation and cytotoxicity of doxorubicin in adriamycin-resistant K562 tumor cells were studied. RESULTS: Doxorubicin-loaded micelles were prepared using a solvent evaporation method with a diameter of 36 nm and a zeta potential of +13.8 mV. The entrapment efficiency of doxorubicin was 48.6% ± 2.3%. The micelles showed sustained release, increased uptake, and cellular cytotoxicity, as well as decreased efflux of doxorubicin in adriamycin-resistant K562 tumor cells. CONCLUSION: This study suggests that PEG-PCL micelles have the potential to reverse multidrug resistance in tumor cells.