Enhanced antitumor activity of different double arms polyethyleneglycol-modified liposomal doxorubicin

The Basic Study of Liposome in Temperature-Sensitive Gel at Body Temperature for Treatment of Peritoneal Dissemination

Peritoneal dissemination is a disease that is difficult to treat surgically because it is widely scattered and proliferates in the abdominal cavity. It is a challenge that even if the drug is administered directly into the abdominal cavity, it rapidly disappears from the abdominal cavity, and the therapeutic effect is not optimal, as expected. In this study, for a liposomal paclitaxel in temperature-sensitive gel that is a suspension before administration and a gel after intraperitoneal administration, the antitumor effect of this formulation was evaluated. Temperature-sensitive gels were prepared using methylcellulose, sodium citrate, and macrogol 4000 and mixed with liposomal paclitaxel. Liposomal paclitaxel containing temperature-sensitive gel in the body was administered into the peritoneal cavity of a mouse model of peritoneal dissemination; the number of cells was significantly reduced compared to a paclitaxel solution of liposomal paclitaxel. These results showed that the liposome in temperature-sensitive gel inhibited cell proliferation in the abdominal cavity. This formulation can be administered easily at room temperature, and it gels and remains in the abdominal cavity for a long period, resulting in a more substantial effect than the existing drug.

Role of stealth lipids in nanomedicine-based drug carriers

The domain of nanomedicine owns a wide-ranging variety of lipid-based drug carriers, and novel nanostructured drug carriersthat are further added to this range every year. The primary goal behind the exploration of any new lipid-based nanoformulation is the improvement of the therapeutic index of the concerned drug molecule along with minimization in the associated side-effects. However, for maintaining a sustained delivery of these intravenously injected lipoidal nanomedicines to the targeted tissues and organ systems in the body, longer circulation in the bloodstream, as well as their stability, are important. After administration, upon recognition as foreign entities in the body, these systems are rapidly cleared by the cells associated with the mononuclear phagocyte system. In order to provide these lipid-based systems with long circulation characteristics, techniques such as coating of the lipoidal surface with an inert polymeric material like polyethylene glycol (PEG) assists in imparting 'stealth properties' to these nanoformulations for avoiding recognition by the macrophages of the immune system. In this review, detailed importance is given to the hydrophilic PEG polymer and the role played by PEG-linked lipid polymers in the field of nanomedicine-based drug carriers. The typical structure and classification of stealth lipids, clinical utility, assemblage techniques, physicochemical characterization, and factors governing the in-vivo performance of the PEG-linked lipids containing formulations will be discussed. Eventually, the novel concept of accelerated blood clearance (ABC) phenomenon associated with the use of PEGylated therapeutics will be deliberated.

The new era of nanotechnology, an alternative to change cancer treatment

In the last few years, nanostructures have gained considerable interest for the safe delivery of therapeutic agents. Several therapeutic approaches have been reported, such as molecular diagnosis, disease detection, nanoscale immunotherapy and anticancer drug delivery that could be integrated into clinical use. The current paper aims to highlight the background that supports the use of nanoparticles conjugated with different types of therapeutic agents, applicable in targeted therapy and cancer research, with a special emphasis on hematological malignancies. A particular key point is the functional characterization of nonviral delivery systems, such as gold nanoparticles, liposomes and dendrimers. The paper also presents relevant published data related to microRNA and RNA interference delivery using nanoparticles in cancer therapy.

Associations of chemo- and radio-resistant phenotypes with the gap junction, adhesion and extracellular matrix in a three-dimensional culture model of soft sarcoma

Background

Three-dimensional (3D) culture models are considered to recapitulate the cell microenvironment in solid tumors, including the extracellular matrix (ECM), cell-cell interactions, and signal transduction. These functions are highly correlated with cellular behaviors and contribute to resistances against chemo- and radio-therapies. However, the biochemical effects and mechanisms remain unknown in soft sarcoma. Therefore, we developed an in vitro 3D model of sarcoma to analyze the reasons of the chemo- and radio-resistance in therapies.

Methods

Four soft sarcoma cell lines, HT1080, RD, SW872, and human osteosarcoma cell line 1 (HOSS1), a cell line established from a patient-derived xenograft, were applied to 3D culture and treated with growth factors in methylcellulose-containing medium. Spheroids were examined morphologically and by western blotting, RT-qPCR, and immunofluorescence staining to analyze cell adhesion, gap junctions, ECM genes, and related factors. Proliferation and colony formation assays were performed to assess chemo- and radio-resistances between 3D and two-dimensional (2D) cell cultures. Annexin V and Propidium Iodide staining was used to detect early apoptotic sarcoma cells treated with Doxorubicin, Gemcitabine, and Docetaxel in the 3D model.

Results

The four soft sarcoma cell lines formed spheres in vitro by culture in modified condition medium. Compared with 2D cell culture, expression of ECM genes and proteins, including COL1A1, LOX, SED1, FN1, and LAMA4, was significantly increased in 3D culture. Analysis of cadherin and gap junction molecules showed significant changes in the gene and protein expression profiles under 3D conditions. These changes affected cell–cell communication and were mainly associated with biological processes such as cell proliferation and apoptosis related to chemo- and radio-resistances.

Conclusions

Our findings revealed significant differences between 3D and 2D cell culture systems, and indicated that cellular responsiveness to external stress such as radiation and chemotherapeutics is influenced by differential expression of genes and proteins involved in regulation of the ECM, cell adhesion, and gap junction signaling.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-015-0175-0) contains supplementary material, which is available to authorized users.

Capacious and programmable multi-liposomal carriers

Spherical polycationic brushes (SPBs) were synthesized by grafting polycationic chains onto 100 nm polystyrene particles. These particles were exposed to unilamellar egg-lecithin (EL) liposomes with a mean diameter of 40 nm that had been rendered anionic via the presence of 10 molar% of phosphatidylserine (PS(1-)). The liposomes also contained 30 mole% of a morpholinocyclohexanol-based lipid (MOCH) that undergoes a conformational flip when the pH is decreased from 7.0 to 5.0. Mixtures of SPBs and liposomes at pH 7 gave an electrostatically-driven complex possessing, on average, about 40 liposomes for each SPB particle. It was found that the bound liposomes rapidly release much of their contents when the pH is reduced from 7.0 to 5.0 owing mostly to a MOCH conformational change that creates defects in the bilayer membrane. The drop in pH does not, however, induce a separation of the liposomes from the SPBs. Around 50-60% of the liposome contents escape before, it is reasoned, lateral and transmembrane motion of the membrane components heals the defects and prevents further release. Remarkably, the liposomes complexed with SPB release their cargo much faster than the identical but non-complexed liposomes.

Negative-charge-functionalized mesoporous silica nanoparticles as drug vehicles targeting hepatocellular carcinoma

In this paper, a series of doxorubicin-loaded and negative-charge-functionalized mesoporous silica nanoparticles (DOX-MSN/COOH) was successfully prepared and used for imaging and targeting therapy of hepatocellular carcinoma. The nanoparticles were uniform and negatively charged, with a diameter of about 55 nm, and a zeta potential of -20 mV. In vitro study showed that the nanoparticles could easily be endocytosed by liver cancer cells (HepG2) and were well-accumulated in the liver by passive targeting. In vivo study proved the ability of DOX-MSN/COOH to inhibit the tumor growth and prolong the survival time of mice bearing hepatocellular carcinoma in situ, giving better results than free DOX. More importantly, histological examination showed no histopathological abnormalities of normal liver cells and heart cells after the administration of DOX-MSN/COOH, while the treatment with free DOX caused damage to those cells. In conclusion, DOX-MSN/COOH exhibited enhanced antitumor efficacy as well as reduced side effects for liver cancer therapy.

Enhanced contrast efficiency in MRI by PEGylated magnetoliposomes loaded with PEGylated SPION: effect of SPION coating and micro-environment

Magnetic core coatings modify the efficiency of nanoparticles used as contrast agents for MRI. In studies of these phenomena, care should be given to take into account possible effects of the specific micro-environment where coated nanoparticles are embedded. In the present work, the longitudinal and transverse relaxivities of superparamagnetic iron oxide nanoparticles stabilized with short-chain polyethylene glycol molecules (PEGylated SPIONs) were measured in a 7T magnetic field. PEGylated SPIONs with two different diameters (5 and 10nm) were studied. Two different PEGylated magnetoliposomes having liposome bilayer membranes composed of egg-phosphatidylcholine, cholesterol and 1,2-distearoyl-sn-glycerol-3-phosphoethanolamine-N-[methoxy PEG-2000] were also studied for their relaxivities, after being loaded with the PEGylated SPION of 5 or 10nm. This type of liposomes is known to have long residence time in bloodstream that leads to an attractive option for therapeutic applications. The influence of the magnetic core coating on the efficiency of the nanosystem as a negative contrast agent for MRI was then compared to the cumulative effect of the coating plus the specific micro-environment components. As a result, it was found that the PEGylated magnetoliposomes present a 4-fold higher efficiency as negative contrast agents for MRI than the PEGylated SPION.