The enhancement of immunosuppressive effects of cyclosporine A on human T-cells using fusogenic liposomes

Targeted-nanoliposomal combretastatin A4 (CA-4) as an efficient antivascular candidate in the metastatic cancer treatment

A number of antiangiogenic drugs have been approved by the Food and Drug Administration which are used in cancer therapy, and variety of other agents in several stages of clinical development or in preclinical assessment. Among these, combretastatin A4 (CA-4) is an under-researched inhibitor of angiogenesis that shows potential activity in the treatment of advanced tumors with migration capacity. However, its clinical application has been limited due to poor water solubility, low bioavailability, rapid metabolism, and systemic elimination. During the last decade, numerous investigations have been done to overcome these problems by using different CA-4 delivery systems or developing produgs of CA-4 or its structural analogs. Nevertheless, these strategies could not be efficient out of the undesired side effects on normal tissues. Nanoliposomal CA-4 not only benefits from the advantage of using liposomal drugs as opposed to free drugs but also can accumulate in the tumor site via specific targeting ligands, which leads to efficient targeting and enhancement of bioavailability. To the best of our knowledge, we consider an important attempt to understand different factors that might influence the CA-4 loading and release pattern of liposomes and the consequent results in tumor therapy. In this review, we shed light on various studied liposomal CA-4 formulations showing application thereof in cancer treatment.

Nanoliposome containing cyclosporine A reduced neuroinflammation responses and improved neurological activities in cerebral ischemia/reperfusion in rat

Cyclosporine A (CsA) is known as a neuroprotective agent against cerebral ischemia/reperfusion (I/R) in animal models. However, the significant therapeutic effects of CsA have been observed in high systemic doses or manipulating the blood-brain barrier, resulting in systemic side effects and toxicity. As the liposome nanocarriers have been developed for efficient delivery of peptide and proteins, liposomal CsA (Lipo-CsA) could improve cerebral (I/R) injuries. In this study, the liposomal CsA formulation (CsA at dose of 2.5 mg/kg) was prepared to assess the brain injury outcomes in 90 min middle cerebral artery occlusion (MCAO) stroke model followed by 48 h reperfusion in treating rats. Five minutes after induction of cerebral ischemia in rats, intravenous (iv) administration of Lipo-CsA significantly (P < 0.001) recovered the infarct size, the brain edema, and the neurological activities compared to corresponding control groups following 48 h I/R. In addition, after 48 h cerebral I/R, Lipo-CsA potentially (P < 0.001) inhibited the inflammation responses including MPO activity and tumor necrosis factor-alpha level in comparison to other groups. In conclusion, the results indicate that the low dose of CsA in liposomal formulation is more effective compared to higher dose of free form of CsA in treatment of ischemic brain in rats.

Cyclosporine A lipid nanoparticles for oral administration: Pharmacodynamics and safety evaluation

The pharmacodynamic effect and the safety of cyclosporine A lipid nanoparticles (CsA LN) for oral administration were investigated using Sandimmune Neoral® as reference. First, the biocompatibility of the unloaded LN on Caco-2 cells was demonstrated. The pharmacodynamic response and blood levels of CsA were studied in Balb/c mice after 5 and 10 days of daily oral administration equivalent to 5 and 15 mg/kg of CsA in different formulations. The in vivo nephrotoxicity after 15 days of treatment at the high dose was also evaluated. The results showed a significant decrease in lymphocyte count (indicator of immunosuppression) for the CsA LN groups which was not observed with Sandimmune Neoral®. CsA blood levels remained constant over the time after treatment with LN, whereas a proportional increase in drug blood concentration was observed with Sandimmune Neoral®. Therefore, CsA LN exhibited a better pharmacological response along with more predictable pharmacokinetic information, diminishing the risk of toxicity. Moreover, a nephroprotective effect against CsA related toxicity was observed in the histopathological evaluation when LN containing Tween® 80 were administered. Therefore, our preliminary findings suggest LN formulations would be a good alternative for CsA oral delivery, enhancing efficacy and reducing the risk of nephrotoxicity.

Halofuginone Synergistically Enhances Anti-Proliferation of Rapamycin in T Cells and Reduces Cytotoxicity of Cyclosporine in Cultured Renal Tubular Epithelial Cells

Both rapamycin (RAPA) and cyclosporin A (CsA) are commonly used for immunosuppression, however their adverse side effects limit their application. Thus, it is of interest to develop novel means to enhance or preserve the immunosuppressive activity of RAPA or CsA while reducing their toxicity. Halofuginone (HF) has been recently tested as a potential immunosuppressant. This study investigated the interaction of HF with RAPA or with CsA in cell cultures. Cell proliferation in cultures was determined using methylthiazol tetrazolium assay, and cell apoptosis assessed by flow cytometric analysis and Western blot. The drug-drug interaction was determined according to Loewe’s equation or Bliss independence. Here, we showed that addition of HF to anti-CD 3 antibody-stimulated splenocyte cultures induced synergistic suppression of T cell proliferation in the presence of RAPA, indicated by an interaction index (γ) value of < 1.0 between HF and RAPA, but not in those with CsA. The synergistic interaction of RAPA with HF in the suppression of T cell proliferation was also seen in a mixed lymphocyte reaction and Jurkat T cell growth, and was positively correlated with an increase in cell apoptosis, but not with proline depletion. In cultured kidney tubular epithelial cells, HF attenuated the cytotoxicity of CsA. In conclusion, these data indicate that HF synergistically enhances anti-T cell proliferation of RAPA and reduces the nephrotoxicity of CsA in vitro, suggesting the potential use of HF for enhancing anti-T cell proliferation of RAPA and reducing CsA-mediated nephrotoxicity.

Functional liposomes in the cancer-targeted drug delivery

Cancer is considered as one of the most severe health problems and is currently the third most common cause of death in the world after heart and infectious diseases. Novel therapies are constantly being discovered, developed and trialed. Many of the current anticancer agents exhibit non-ideal pharmaceutical and pharmacological properties and are distributed non-specifically throughout the body. This results in death of the both normal healthy and malignant cells and substantially leads to accruing a variety of serious toxic side effects. Therefore, the efficient systemic therapy of cancer is almost impossible due to harmful side effects of anticancer agents to the healthy organs and tissues. Furthermore, several problems such as low bioavailability of the drugs, low drug concentrations at the site of action, lack of drug specificity and drug-resistance also cause many restrictions on clinical applications of these drugs in the tumor therapy. Different types of the liposomal formulations have been used in medicine due to their distinctive advantages associated with their structural flexibility in the encapsulation of various agents with different physicochemical properties. They can also mediate delivery of the cargo to the appropriate cell type and subcellular compartment, reducing the effective dosage and possible side effects which are related to high systemic concentrations. Therefore, these novel systems were found very promising and encouraging dosage forms for the treatment of different types of cancer by increasing efficiency and reducing the systemic toxicity due to the specific drug delivery and targeting.

Preparation and evaluation of cyclosporin A-containing proliposomes: a comparison of the supercritical antisolvent process with the conventional film method

Objectives

The objectives of this study were to prepare cyclosporin A (CsA)-containing proliposomes using the supercritical antisolvent (SAS) process and the conventional thin film method for the comparative study of proliposomal formulations and to evaluate the physicochemical properties of these proliposomes.

Methods

CsA-containing proliposomes were prepared by the SAS process and the conventional film method, composed of natural and synthetic phospholipids. We investigated particle size, polydispersity index, and zeta potential of CsA-containing proliposomes. In addition, both production yield and entrapment efficiency of CsA in different proliposomes were analyzed. Physicochemical properties of CsA-containing proliposomes were also evaluated, using differential scanning calorimetry and X-ray diffraction. The morphology and size of CsA-containing proliposomes were confirmed, using scanning electron microscopy. We checked the in vitro release of CsA from CsA-containing proliposomes prepared by different preparation methods, comparing them with Restasis^® as a positive control and the stability of SAS-mediated proliposomes was also studied.

Results

CsA-containing proliposomes formed by the SAS process had a relatively smaller particle size, with a narrow size distribution and spherical particles compared with those of conventionally prepared proliposomes. The yield and entrapment efficiency of CsA in all proliposomes varied from 85% to 92% and from 86% to 89%, respectively. Differential scanning calorimetry and X-ray diffraction studies revealed that the anhydrous lactose powder used in this formulation retained its crystalline form and that CsA was present in an amorphous form. Proliposome powders were rapidly converted to liposomes on contact with water. The in vitro release study of proliposomal formulations demonstrated a similar pattern to Restasis^®. The SAS-mediated CsA-containing proliposomes were stable on storage, with no significant changes in particle size, polydispersity index, and entrapment efficiency.

Conclusion

These results show promising features of CsA-containing proliposomal formulations, using the SAS process for the large-scale industrial application.

Assessment of cytotoxic properties of safranal and nanoliposomal safranal in various cancer cell lines

Saffron (Crocus sativus) is a widely used food additive used for its color and taste. It has been reported that saffron possesses significant in vivo and in vitro anti-tumor activity. In the present study, anti-tumor effects of safranal, the major aromatic compound in saffron, and its liposomal form were investigated. The role of apoptosis has also been explored in this toxicity. HeLa, MCF7 and L929 cell lines were cultured and exposed to safranal (0.01-3 mM) or liposomal safranal (0.04-0.32 mM). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) assay was performed to assess cytotoxicity. Apoptosis was evaluated by staining cells with propidium iodide and quantifying sub-Gl peak by flow cytometry. MTT assay revealed a significant and concentration-dependent cytotoxic effect of safranal on HeLa and MCF7 cell lines. Liposomal safranal showed enhanced effect compared to the safranal solution, as compared by their IC50 concentrations. Flow cytometry results revealed induction of apoptosis by safranal. It might be concluded that safranal could be involved in saffron-induced cell death in HeLa and MCF7 cells. Liposome encapsulation improved anti-tumor effect of safranal. Safranal and particularly its liposomal form could be investigated as promising chemotherapeutic agents in cancer treatment.

Characterization and stability studies of a novel liposomal cyclosporin A prepared using the supercritical fluid method: comparison with the modified conventional Bangham method

A novel method to prepare cyclosporin A encapsulated liposomes was introduced using supercritical fluid of carbon dioxide (SCF-CO₂) as an antisolvent. To investigate the strength of the newly developed SCF-CO₂ method compared with the modified conventional Bangham method, particle size, zeta potential, and polydispersity index (PDI) of both liposomal formulations were characterized and compared. In addition, entrapment efficiency (EE) and drug loading (DL) characteristics were analyzed by reversed-phase high-performance liquid chromatography. Significantly larger particle size and PDI were revealed from the conventional method, while EE (%) and DL (%) did not exhibit any significant differences. The SCF-CO₂ liposomes were found to be relatively smaller, multilamellar, and spherical with a smoother surface as determined by transmission electron microscopy. SCF-CO₂ liposomes showed no significant differences in their particle size and PDI after more than 3 months, whereas conventional liposomes exhibited significant changes in their particle size. The initial yield (%), EE (%), and DL (%) of SCF-CO₂ liposomes and conventional liposomes were 90.98 ± 2.94, 92.20 ± 1.36, 20.99 ± 0.84 and 90.72 ± 2.83, 90.24 ± 1.37, 20.47 ± 0.94, respectively, which changed after 14 weeks to 86.65 ± 0.30, 87.63 ± 0.72, 18.98 ± 0.22 and 75.04 ± 8.80, 84.59 ± 5.13, 15.94 ± 2.80, respectively. Therefore, the newly developed SCF-CO₂ method could be a better alternative compared with the conventional method and may provide a promising approach for large-scale production of liposomes.

Improvement of cytotoxic and apoptogenic properties of crocin in cancer cell lines by its nanoliposomal form

OBJECTIVE

Saffron Crocus sativus L. (Iridaceae) is known for anticancer properties. However, limited effort has been made to correlate these effects to the active ingredients of saffron. In the present study, cytotoxic effects of crocin, the major coloring compound in saffron, and its nanoliposomal form for better cellular delivery are investigated.

METHODS

HeLa and MCF-7 cells were cultured and exposed to crocin (1, 2, and 4 mM) and liposomal crocin (0.5 and 1 mM). The 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was performed to assess cytotoxicity. Apoptotic cells were determined using propidium iodide (PI) staining of DNA fragmentation by flow cytometry.

RESULTS

MTT assay revealed a remarkable and concentration-dependent cytotoxic effect of crocin on HeLa and MCF-7 cells in comparison with non-malignant cell line (L929). Crocin liposomal forms (IC(50) values after 48 h: 0.61, 0.64, and 1.2 mM) showed enhanced cytotoxic effect compared with the crocin (IC(50) after 48 h: 1.603 mM) in HeLa cells. Crocin and its liposomal form induced a sub-G1 peak in flow cytometry histogram of treated cells indicating apoptosis is involved in this toxicity. Liposomal encapsulation enhances apoptogenic effects of crocin on cancerous cells.

CONCLUSION

It might be concluded that crocin and its liposomes could cause cell death in HeLa and MCF-7 cells, in which liposomal encapsulation improved cytotoxic effects. They could be also considered as a promising chemotherapeutic agent in cancer treatment in future.

The influence of size, lipid composition and bilayer fluidity of cationic liposomes on the transfection efficiency of nanolipoplexes

Among non-viral vectors, cationic liposomes are the most promising carriers in gene delivery. But the most critical issue about their application is their low transfection efficiency compared to viral vectors. In this study, we tried to make a comparison between transfection efficiency of different liposomal formulations and to investigate the effect of membrane fluidity and other physical properties of liposomes and lipoplexes such as size and charge ratio on the transfection efficiency in in vitro environment. Different gene delivery systems were developed by using liposomes composed of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) or 3-beta-[N-(N'N'-dimethylaminoethane)-carbamoyl] cholesterol (DC-CHOL) in combination with other lipids including 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), egg L-alpha-phosphatidylcholine (EPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE). These multilamellar vesicle (MLV) liposomes were extruded through 100 nm polycarbonate filters to produce small unilamellar vesicles (SUVs). Transfection activity of these lipoplexes in Neuro2A cells was tested using pRL-CMV encoding Renilla luciferase. We could not establish any direct correlation between high fluid membranes and high transfection efficiency because DOTAP:DPPE had a better result than DOTAP:DOPE while DC-CHOL:DOPE was more successful in gene transfer than DC-CHOL:DPPE. It was revealed that the use of these two helper lipids with different Tm (DPPE: 64 degrees C and DOPE: -11 degrees C) along with DOTAP increased transfection efficiency but formulation of these phospholipids with DC-CHOL was led to a significant reduction in transfection activity. Generally, DOTAP:DPPE, DC-CHOL:DOPE and DOTAP:DOPE:DPPE formulations showed the highest transfection activity. The results of this study showed that, in designing of liposome based non-viral vectors, different parameters such as size, lipid composition and the use of helper lipid should be considered.