Optimizing Antitumor Efficacy and Adverse Effects of Pegylated Liposomal Doxorubicin by Scheduled Plasmapheresis: Impact of Timing and Dosing

Administration of Liposomal-Based Pde3b Gene Therapy Protects Mice Against Collagen-Induced Rheumatoid Arthritis via Modulating Macrophage Polarization

Background

Rheumatoid arthritis (RA) is a chronic and systemic autoimmune disease characterized by synovial inflammation and joint destruction. Despite progress in RA therapy, it remains difficult to achieve long-term remission in RA patients. Phosphodiesterase 3B (Pde3b) is a member of the phosphohydrolyase family that are involved in many signal transduction pathways. However, its role in RA is yet to be fully addressed.

Methods

Studies were conducted in arthritic DBA/1 mice, a suitable mouse strain for collagen-induced rheumatoid arthritis (CIA), to dissect the role of Pde3b in RA pathogenesis. Next, RNAi-based therapy with Pde3b siRNA-loaded liposomes was assessed in a CIA model. To study the mechanism involved, we investigated the effect of Pde3b knockdown on macrophage polarization and related signaling pathway.

Results

We demonstrated that mice with CIA exhibited upregulated Pde3b expression in macrophages. Notably, intravenous administration of liposomes loaded with Pde3b siRNA promoted the macrophage anti-inflammatory program and alleviated CIA in mice, as indicated by the reduced inflammatory response, synoviocyte infiltration, and bone and cartilage erosion. Mechanistic study revealed that depletion of Pde3b increased cAMP levels, by which it enhanced PKA-CREB-C/EBPβ pathway to transcribe the expression of anti-inflammatory program-related genes.

Conclusion

Our results support that Pde3b is involved in the pathogenesis of RA, and Pde3b siRNA-loaded liposomes might serve as a promising therapeutic approach against RA.

Conventional and PEGylated Liposomes as Vehicles of Copaifera sabulicola

Traditional medicine uses resin oils extracted from plants of the genus Copaifera for several purposes. Resin oils are being studied to understand and profile their pharmacological properties. The aim of this work was to prepare and to characterize conventional and pegylated liposomes incorporating resin oils or the hexanic extract obtained from Copaifera sabulicola (copaiba) leaves. The cytotoxic effect of these products was also investigated. Conventional and stealth liposomes with copaiba extract showed similar average diameters (around 126 nm), encapsulation efficiencies greater than 75% and were stable for 90 days. A cytotoxicity test was performed on murine glioma cells and the developed liposomes presented antiproliferative action against these cancer cells at the average concentration of 30 μg/mL. Phytochemicals encapsulated in PEGylated liposomes induced greater reduction in the viability of tumor cells. In addition, bioassay-s measured the cytotoxicity of copaiba resin oil (Copaifera sabulicola) in liposomes (conventional and PEGylated), which was also checked against pheochromocytoma PC12 cells. Its safety was verified in normal rat astrocytes. The results indicate that liposomes encapsulating copaiba oil showed cytotoxic activity against the studied tumor strains in a dose-dependent fashion, demonstrating their potential applications as a chemotherapeutic bioactive formulation.

Blockade of Mbd2 by siRNA-loaded liposomes protects mice against OVA-induced allergic airway inflammation via repressing M2 macrophage production

Objective

To address the role of methyl-CpG-binding domain 2 (MBD2) in the pathogenesis of asthma and its potential as a target for the asthmatic therapy.

Methods

Studies were conducted in asthmatic patients and macrophage-specific Mbd2 knockout mice to dissect the role of MBD2 in asthma pathogenesis. Additionally, RNAi-based therapy with Mbd2 siRNA-loaded liposomes was conducted in an ovalbumin (OVA)-induced allergic airway inflammation mouse model.

Results

Asthmatic patients and mice challenged with OVA exhibited upregulated MBD2 expression in macrophages, especially in alternatively activated (M2) macrophages. In particular, macrophage-specific knockout of Mbd2 protected mice from OVA-induced allergic airway inflammation and suppressed the M2 program. Notably, intratracheal administration of liposomes carrying Mbd2 siRNA decreased the expression of Mbd2 and prevented OVA-induced allergic airway inflammation in mice, as indicated by the attenuated airway inflammation and mucus production.

Conclusions

The above data indicate that Mbd2 implicates in the pathogenesis of asthma predominantly by regulating the polarization of M2 macrophages, which supports that Mbd2 could be a viable target for treatment of asthma in clinical settings.

Therapeutic Apheresis, Circulating PLD, and Mucocutaneous Toxicity: Our Clinical Experience through Four Years

Cancer treatment has been greatly improved by the combined use of targeted therapies and novel biotechnological methods. Regarding the former, pegylated liposomal doxorubicin (PLD) has a preferential accumulation within cancer tumors, thus having lower toxicity on healthy cells. PLD has been implemented in the targeted treatment of sarcoma, ovarian, breast, and lung cancer. In comparison with conventional doxorubicin, PLD has lower cardiotoxicity and hematotoxicity; however, PLD can induce mucositis and palmo-plantar erythrodysesthesia (PPE, hand-foot syndrome), which limits its use. Therapeutical apheresis is a clinically proven solution against early PLD toxicity without hindering the efficacy of the treatment. The present review summarizes the pharmacokinetics and pharmacodynamics of PLD and the beneficial effects of extracorporeal apheresis on the incidence of PPE during chemoradiotherapy in cancer patients.

Plasmafiltration as an effective method in the removal of circulating pegylated liposomal doxorubicin (PLD) and the reduction of mucocutaneous toxicity during the treatment of advanced platinum-resistant ovarian cancer

PURPOSE

The present study evaluates the safety and efficacy of double-plasma filtration (PF) to remove the exceeding pegylated liposomal doxorubicin (PLD) in circulation, thus reducing mucocutaneous toxicity.

METHODS

A total of 16 patients with platinum-resistant ovarian cancer were treated with 50 mg/m² PLD applied in 1-h IV infusion every 28 days. PF was scheduled at 44-46 h post-infusion. The concentration of plasma PLD and non-liposomal doxorubicin (NLD) was monitored with high-performance liquid chromatography at 116 h post-infusion. A non-linear method for mixed-effects was used in the population pharmacokinetic model. The dose fraction of PLD eliminated by the patient prior to PF was compared with the fraction removed by PF. PLD-related toxicity was recorded according to CTCAE v4.0 criteria and compared to historical data. Anticancer effects were evaluated according to RECIST 1.1 criteria.

RESULTS

The patients received a median of 3 (2-6) chemotherapy cycles. A total of 53 cycles with PF were evaluated, which removed 31% (10) of the dose; on the other hand, the fraction eliminated prior to PF was of 34% (7). Exposure to NLD reached only 10% of exposure to the parent PLD. PLD-related toxicity was low, finding only one case of grade 3 hand-foot syndrome (6.7%) and grade 1 mucositis (6.7%). Other adverse effects were also mild (grade 1-2). PF-related adverse effects were low (7%). Median progression-free survival (PFS) and overall survival (OS) was of 3.6 (1.5-8.1) and 7.5 (1.7-26.7) months, respectively. Furthermore, 33% of the patients achieved stable disease (SD), whereas that 67% progressed.

CONCLUSION

PF can be considered as safe and effective for the extracorporeal removal of PLD, resulting in a lower incidence of mucocutaneous toxicity.

Arsenic trioxide encapsulated liposomes prepared via copper acetate gradient loading method and its antitumor efficiency

In this study, arsenic trioxide (ATO) was encapsulated in liposomes via copper acetate (Cu(OAc)₂) gradients and high entrapment efficiency of over 80% was obtained. The average particle size and the zeta-potential of the liposomes were detected to be 115.1 ± 29.1 nm and −21.97 ± 0.6 mV, respectively. The TEM images showed rod-like precipitates in the inner aqueous phase, which was supposed be due to the formation of insoluble ATO—Cu complex. The in vitro drug release of ATO—Cu liposomes exhibited a sustained release over 72 h, and the release rates decreased with the increase of the pH of release media. Pharmacokinetic and tissue distribution studies of ATO liposomes showed significantly reduced plasma clearance rate, increased AUC_0–12h and T_1/2, and improved tumor distribution of As compared to iv administration of ATO solution. The anti-tumor effect of ATO loaded liposomes to S180 tumor-bearing mice was significantly improved with a tumor inhibition rate of 61.2%, meanwhile the toxicity of encapsulated ATO was greatly decreased. In conclusion, ATO can be effectively encapsulated into liposomes by remote loading method via Cu(OAc)₂ gradients; the co-administration of ATO and Cu(II) via liposomal formulation may find wide applications in the treatment of various tumors.