Oestrone-targeted liposomes for mitoxantrone delivery via oestrogen receptor - synthesis, physicochemical characterization and in-vitro evaluation

A novel estrogen-targeted PEGylated liposome co-delivery oxaliplatin and paclitaxel for the treatment of ovarian cancer

Ovarian cancer is the second cause of death among gynecological malignancies. In this study, we designed a novel estrogen-targeted PEGylated liposome loaded with oxaliplatin and paclitaxel (ES-SSL-OXA/PTX) which could target estrogen receptor (ER) highly expressed on the surface of SKOV-3 cells to enhance therapeutic efficacy and reduce the side effects for SKOV-3 tumor therapy. ES-SSL-OXA/PTX was prepared by thin film hydration method and exhibited a uniform spherical morphology. Encapsulation efficiency (EE) were determined by HPLC method with the results of 44.10% for OXA and 65.85% for PTX. The mean particle size and polydispersity index (PDI) were 168.46 nm and 0.145, respectively. In vivo and in vitro targeting study confirmed that ES-SSL-OXA/PTX has optimum specific targeting ability. Meanwhile, In vitro and in vivo antitumor results of ES-SSL-OXA/PTX exhibited a superior antiproliferative effect on SKOV-3 cells and a stronger anti-tumor efficacy with the tumor inhibition rate of 85.24%. The pharmacokinetics results of ES-SSL-OXA/PTX showed a prolonged half-life time and a slowed clearance rate. The preliminary safety study of acute toxicity and long-term toxicity demonstrated ES-SSL-OXA/PTX exhibited a reduced toxicity profile. Based on the above results, ES-SSL-OXA/PTX could be a promising novel formulation for the treatment of ovarian cancer in future clinic.

Efficient Delivery of Gemcitabine by Estrogen Receptor-Targeted PEGylated Liposome and Its Anti-Lung Cancer Activity In Vivo and In Vitro

Lung cancer is one of the main causes of cancer-related deaths. At present, the main treatment method for lung cancer is chemotherapy. Gemcitabine (GEM) is widely applied in lung cancer treatment, but its lack of targeting ability and serious side effects limit its application. In recent years, nanocarriers have become the focus of research to solve the above problems. Here, we prepared estrone (ES)-modified GEM-loaded PEGylated liposomes (ES-SSL-GEM) for enhanced delivery by identifying the overexpressed estrogen receptor (ER) on lung cancer A549 cells. We studied the characterization, stability, release behavior, cytotoxicity, targeting ability, endocytosis mechanism, and antitumor ability to prove the therapeutic effect of ES-SSL-GEM. The results showed that ES-SSL-GEM presented a uniform particle size of 131.20 ± 0.62 nm, a good stability, and a slowly released behavior. Moreover, ES-SSL-GEM enhanced tumor-targeting ability, and the endocytosis mechanism studies confirmed that the ER-mediated endocytosis had the most crucial effect. Furthermore, ES-SSL-GEM had the best inhibitory effect on A549 cell proliferation and significantly suppressed the tumor growth in vivo. These results suggest that ES-SSL-GEM is a promising agent for treating lung cancer.

Peptide Engraftment on PEGylated Nanoliposomes for Bone Specific Delivery of PTH (1-34) in Osteoporosis

Bone-specific functionalization strategies on liposomes are promising approaches to delivering the drug in osteoporotic conditions. This approach delivers the drug to the bone surface specifically, reduces the dose and off-target effects of the drug, and thereby reduces the toxicity of the drug. The purpose of the current research work was to fabricate the bone-specific peptide conjugated pegylated nanoliposomes to deliver anabolic drug and its physicochemical evaluations. For this, a bone-specific peptide (SDSSD) was synthesized, and the synthesized peptide was conjugated with a linker (DSPE-PEG2000-COOH) to obtain a bone-specific conjugate (SDSSD-DSPE). Purified SDSSD-DSPE was characterized by HPLC, Maldi-TOF, NMR, and Scanning Electron Microscope/Energy Dispersive Spectroscopy (SEM/EDS). Further, peptide-conjugated and anabolic drug-encapsulated liposomes (SDSSD-LPs) were developed using the ethanol injection method and optimized by Central Composite Design (CCD) using a statistical approach. Optimized SDSSD-LPs were evaluated for their physicochemical properties, including surface morphology, particle size, zeta potential, in vitro drug release, and bone mineral binding potential. The obtained results from these studies demonstrated that SDSSD-DSPE conjugate and SDSSD-LPs were optimized successfully. The particle size, % EE, and zeta potential of SDSSD-LPs were observed to be 183.07 ± 0.85 nm, 66.72 ± 4.22%, and -25.03 ± 0.21 mV, respectively. SDSSD-LPs demonstrated a sustained drug release profile. Further, the in vitro bone mineral binding assay demonstrated that SDSSD-LPs deliver the drug to the bone surface specifically. These results suggested that SDSSD-LPs could be a potential targeting approach to deliver the anabolic drug in osteoporotic conditions.

Estrone-Conjugated PEGylated Liposome Co-Loaded Paclitaxel and Carboplatin Improve Anti-Tumor Efficacy in Ovarian Cancer and Reduce Acute Toxicity of Chemo-Drugs

Purpose

Ovarian cancer is the most lethal gynecologic malignancy. The combination of paclitaxel (PTX) and carboplatin (CBP) is the first-line remedy for clinical ovarian cancer. However, due to the limitations of adverse reaction and lacking of targeting ability, the chemotherapy of ovarian cancer is still poorly effective. Here, a novel estrone (ES)-conjugated PEGylated liposome co-loaded PTX and CBP (ES-PEG-Lip-PTX/CBP) was designed for overcoming the above disadvantages.

Methods

ES-PEG-Lip-PTX/CBP was prepared by film hydration method and could recognize estrogen receptor (ER) over-expressing on the surface of SKOV-3 cells. The characterizations, stability and in vitro release of ES-PEG-Lip-PTX/CBP were studied. In vitro cellular uptake and its mechanism were observed by fluorescence microscope. In vivo targeting effect in tumor-bearing mice was determined. Pharmacokinetics and biodistribution were studied in ICR mice. In vitro cytotoxicity and in vivo anti-tumor efficacy were evaluated on SKOV-3 cells and tumor-bearing mice, respectively. Finally, the acute toxicity in ICR mice was explored for assessing the preliminary safety of ES-PEG-Lip-PTX/CBP.

Results

Our results showed that ES-PEG-Lip-PTX/CBP was spherical shape without aggregation. ES-PEG-Lip-PTX/CBP exhibited the optimum targeting effect on uptake in vitro and in vivo. The pharmacokinetics demonstrated ES-PEG-Lip-PTX/CBP had improved the pharmacokinetic behavior. In vitro cytotoxicity showed that ES-PEG-Lip-PTX/CBP maximally inhibited SKOV-3 cell proliferation and its IC₅₀ values was 1.6 times lower than that of non-ES conjugated liposomes at 72 h. The in vivo anti-tumor efficacy study demonstrated that ES-PEG-Lip-PTX/CBP could lead strong SKOV-3 tumor growth suppression with a tumor volume inhibitory rate of 81.8%. Meanwhile, acute toxicity studies confirmed that ES-PEG-Lip-PTX/CBP significantly reduced the toxicity of the chemo drugs.

Conclusion

ES-PEG-Lip-PTX/CBP was successfully prepared with an optimal physicochemical and ER targeting property. The data of pharmacokinetics, anti-tumor efficacy and safety study indicated that ES-PEG-Lip-PTX/CBP could become a promising therapeutic formulation for human ovarian cancer in the future clinic.

In vitro and in vivo Evaluation of a Novel Estrogen-Targeted PEGylated Oxaliplatin Liposome for Gastric Cancer

Background

Chemotherapy is still the main first-line treatment for advanced metastatic gastric cancer, but it has the limitations of serious side effects and drug resistance. Conventional liposome has been substantially used as drug carriers, but they lack targeting character with lower drug bioavailability in tumor tissues. Based on the above problems, a novel estrogen-targeted PEGylated liposome loaded with oxaliplatin (ES-SSL-OXA) was prepared to further improve the metabolic behavior, the safety profile, and the anti-tumor efficacy of oxaliplatin.

Methods

Four kinds of oxaliplatin (OXA) liposomes were prepared by film hydration method. The obtained formulations were characterized in terms of entrapment efficiency (EE), particle size, and so on by HPLC and DLS (dynamic light scanning). The morphology of ES-SSL-OXA was detected by transmission electron microscope (TEM). The in vitro and in vivo targeting effect of ES-SSL-OXA was verified by fluorescence microscopy and in vivo imaging system in gastric cancer cells (SGC-7901) and tumor-bearing athymic mice. The in vitro and in vivo antitumor efficacies of ES-SSL-OXA were investigated on SGC-7901 cells and athymic tumor-bearing mice. Pharmacokinetic, biodistribution, and acute toxicity tests of ES-SSL-OXA were performed on ICR mice.

Results

The ES-SSL-OXA exhibited an average particle size of about 153.37 nm with an encapsulation efficiency of 46.20% and low leakage rates at 4°C and 25°C. In vivo and in vitro targeting study confirmed that ES-SSL-OXA could effectively target the tumor site. The antitumor activity demonstrated the strongest inhibition in tumor growth of ES-SSL-OXA. Pharmacokinetics and acute toxicity study showed that ES-SSL-OXA could significantly improve the metabolic behavior and toxicity profile of oxaliplatin.

Conclusion

In this study, a novel estrogen-targeted long-acting liposomal formulation of OXA was successfully prepared. ES fragment effectively targeted the delivery system to tumor tissues which highly express estrogen receptor, providing a promising therapeutic method for gastric cancer in clinic.

Receptor-Mediated Targeted Delivery of Surface-ModifiedNanomedicine in Breast Cancer: Recent Update and Challenges

Breast cancer therapeutic intervention continues to be ambiguous owing to the lack of strategies for targeted transport and receptor-mediated uptake of drugs by cancer cells. In addition to this, sporadic tumor microenvironment, prominent restrictions with conventional chemotherapy, and multidrug-resistant mechanisms of breast cancer cells possess a big challenge to even otherwise optimal and efficacious breast cancer treatment strategies. Surface-modified nanomedicines can expedite the cellular uptake and delivery of drug-loaded nanoparticulate constructs through binding with specific receptors overexpressed aberrantly on the tumor cell. The present review elucidates the interesting yet challenging concept of targeted delivery approaches by exploiting different types of nanoparticulate systems with multiple targeting ligands to target overexpressed receptors of breast cancer cells. The therapeutic efficacy of these novel approaches in preclinical models is also comprehensively discussed in this review. It is concluded from critical analysis of related literature that insight into the translational gap between laboratories and clinical settings would provide the possible future directions to plug the loopholes in the process of development of these receptor-targeted nanomedicines for the treatment of breast cancer.

Estrone-targeted liposomes for mitoxantrone delivery via estrogen receptor: In vivo targeting efficacy, antitumor activity, acute toxicity and pharmacokinetics

Estrogen receptor (ER) is a potential target receptor for ER-positive cancer therapy including breast cancers, gastric cancers, and human acute myeloblastic leukaemia. In order to reduce the side-effects of mitoxantrone (MTO), estrone-targeted liposomes for MTO delivery via ER were designed for selectively targeting cancer cells. In previous studies, MTO-loaded estrogen receptor targeted and sterically stabilized liposome (ES-SSL-MTO; ES: estrone, is known to bind the ER) had been synthesized and showed a very high antiproliferative effect with IC₅₀ value of 0.7 ng/mL. Based on these, further studies including in vivo targeting efficacy and antitumor activity, acute toxicity and pharmacokinetics of MTO liposomes were carried out. The results showed SSL (sterically stabilized liposome, PEGylated liposome, PEG: Polyethylene Glycol) could reduce drug metabolism, improve the stability of liposomes, prolong in vivo circulation time of drugs, reduce the toxicity of MTO. But SSL could not be enriched in tumor tissues. However, estrone (ES)-targeted liposomes could be delivered to tumor sites. ES-SSL could effectively enter into ER-expressing tumor cellsand be accumulated, prolong the circulation time in vivo, reduce side effects of drug. ES-SSL-MTO could provide higher bioavailability than MTO, enhance the anti-tumor effect and the safety of MTO, reduce the toxicity and side effects of MTO and improve the therapeutic effect of MTO. These facts proved ES-SSL is a useful tumor-targeting drug delivery system for MTO.

An in vitro evaluation of antitumor activity of sirolimus-encapsulated liposomes in breast cancer cells

OBJECTIVES

Design and examine the effect of sirolimus-PEGylated (Stealth) liposomes for breast cancer treatment. In this study, we developed conventional and Stealth liposome nanoparticles comprising of distearoylphosphatidylcholine (DSPC) or dipalmitoyl-phosphatidylcholine (DPPC) and DSPE-MPEG-2000 lipids loaded with sirolimus as an anticancer agent. The effect of lipid grade, drug loading and incubation times were evaluated.

METHODS

Particle size distribution, encapsulation efficiency of conventional and Stealth liposomes were studied followed by cytotoxicity evaluation. The cellular uptake and internal localisation of liposome formulations were investigated using confocal microscopy.

KEY FINDINGS

The designed Stealth liposome formulations loaded with sirolimus demonstrated an effective in vitro anticancer therapy compared with conventional liposomes while the length of the acyl chain affected the cell viability. Anticancer activity was found to be related on the drug loading amounts and incubation times. Cell internalization was observed after 5 h while significant cellular uptake of liposome was detected after 24 h with liposome particles been located in the cytoplasm round the cell nucleus. Sirolimus Stealth liposomes induced cell apoptosis.

CONCLUSIONS

The design and evaluation of sirolimus-loaded PEGylated liposome nanoparticles demonstrated their capacity as drug delivery carrier for the treatment of breast cancer tumours.

Surface engineering of nanomaterials with phospholipid-polyethylene glycol-derived functional conjugates for molecular imaging and targeted therapy

In recent years, phospholipid-polyethylene glycol-derived functional conjugates have been widely employed to decorate different nanomaterials, due to their excellent biocompatibility, long blood circulation characteristics, and specific targeting capability. Numerous in vivo studies have demonstrated that nanomedicines peripherally engineered with phospholipid-polyethylene glycol-derived functional conjugates show significantly increased selective and efficient internalization by target cells/tissues. Targeting moieties including small-molecule ligands, peptides, proteins, and antibodies are generally conjugated onto PEGylated phospholipids to decorate liposomes, micelles, hybrid nanoparticles, nanocomplexes, and nanoemulsions for targeted delivery of diagnostic and therapeutic agents to diseased sites. In this review, the synthesis methods of phospholipid-polyethylene glycol-derived functional conjugates, biophysicochemical properties of nanomedicines decorated with these conjugates, factors dominating their targeting efficiency, as well as their applications for in vivo molecular imaging and targeted therapy were summarized and discussed.

Co-delivery of epirubicin and paclitaxel using an estrone-targeted PEGylated liposomal nanoparticle for breast cancer

Breast cancer is one of the most frequent malignancies in the female population. Recently, the development of medical products has been advanced for this disease; however, patients still suffer from the failure of current treatments and new therapeutic strategies are urgently required. In this study, due to the overexpression of the estrogen receptor (ER) in breast cancer and the ability of ER to specifically bind to its ligand estrone (ES), an ES-targeted PEGylated epirubicin (EPI) and paclitaxel (PTX) co-loaded liposomal nanoparticle (NP) (termed as ES-SSL-EPI/PTX) was developed. Physicochemical studies demonstrated that the ES-SSL-EPI/PTX had a nanoscaled particle size (~120 nm) and a neutral zeta potential (~-5 mV) and presented favorable stability in physiological media. In vitro, the ES-SSL-EPI/PTX showed a significantly higher cellular uptake in human breast cancer MCF-7 cells mainly via the receptor-ligand mediated pathway resulting in effective cytotoxic activity. In vivo targeting study, the accumulation of targeted liposomes in tumor was significantly improved. The systemic circulation time and biodistribution in main organs of EPI and PTX delivered by ES-SSL-Liposomes were increased. Consequently, the ES-SSL-EPI/PTX significantly suppressed tumor growth in the MCF-7-derived tumor-bearing mouse model without inducing toxicity. These results suggested that the ES-SSL-EPI/PTX was a promising formulation for co-delivery of chemotherapeutics in the treatment of breast cancer.