Dual pH-sensitive micelles with charge-switch for controlling cellular uptake and drug release to treat metastatic breast cancer.

For successful chemotherapy against metastatic breast cancer, the great efforts are still required for designing drug delivery systems that can be selectively internalized by tumor cells and release the cargo in a controlled manner. In this work, the chemotherapeutic agent paclitaxel (PTX) was loaded with the dual-pH sensitive micelle (DPM), which consisted of a pH-sensitive core, an acid-cleavable anionic shell, and a polyethylene glycol (PEG) corona. In the slightly acidic environment of tumor tissues, the anionic shell was taken off, inducing the conversion of the surface charge of DPM from negative to positive, which resulted in more efficient cellular uptake, stronger cytotoxicity and higher intra-tumor accumulation of PTX in the murine breast cancer 4T1 tumor-bearing mice models compared to the micelles with irremovable anionic or non-ionic shell. Meanwhile, the pH-sensitive core endowed DPM with rapid drug release in endo/lysosomes. The inhibitory rates of DPM against tumor growth and lung metastasis achieved 77.7% and 88.3%, respectively, without significant toxicity. Therefore, DPM is a promising nanocarrier for effective therapy of metastatic breast cancer due to satisfying the requirements of both selective uptake by tumor cells and sufficient and fast intracellular drug release.

Cancer-Cell-Biomimetic Nanoparticles for Targeted Therapy of Homotypic Tumors.

A unique biomimetic drug-delivery system composed of 4T1-breast-cancer-cell membranes and paclitaxel-loaded polymeric nanoparticles (PPNs) (cell-membrane-coated PPNs), demonstrates superior interactions to its source tumor cells and elongated blood circulation, and displays highly cell-specific targeting of the homotypic primary tumor and metastases, with successful inhibition of the growth and lung metastasis of the breast cancer cells.

Inhibition of Breast Cancer Metastasis by Pluronic Copolymers with Moderate Hydrophilic-Lipophilic Balance.

Metastasis is the primary cause resulting in the high mortality of breast cancer. The inherent antimetastasis bioactivity of Pluronic copolymers with a wide range of hydrophilic-lipophilic balance (HLB) including Pluronic L61, P85, P123, F127, F68, and F108 was first explored on metastatic 4T1 breast cancer cells. The results indicated that P85 and P123 could strongly inhibit the migration and invasion of 4T1 cells. The effects of the polymers on cell healing, migration, and invasion exhibited bell-shaped dependencies on HLB of Pluronic copolymers, and the better antimetastasis effects of Pluronic copolymers could be achieved with the HLB between 8 and 16. P85 and P123 themselves could significantly inhibit pulmonary metastasis in 4T1 mammary tumor metastasis model in situ. In addition, a synergetic antimetastasis effect could be achieved during drug combination of doxorubicin hydrochloride (DOX) and P85 or P123 intravenously. The metastasis effects of P85 and P123 both in vitro and in vivo were partially attributed to the downregulation of matrix metalloproteinase-9 (MMP-9). Therefore, Pluronic copolymers with moderate HLB 8-16 such as P85 and P123 could be promising excipients with therapeutics in drug delivery systems to inhibit breast cancer metastasis.

Inhibition of metastasis and growth of breast cancer by pH-sensitive poly (ß-amino ester) nanoparticles co-delivering two siRNA and paclitaxel.

Breast cancer is the most vicious killer for women's health, while metastasis is the main culprit, which leads to failure of treatment by increasing relapse rate. In this work, a new complexes nanoparticles loading two siRNA (Snail siRNA (siSna) and Twist siRNA (siTwi)) and paclitaxel (PTX) were designed and constructed using two new amphiphilic polymer, polyethyleneimine-block-poly[(1,4-butanediol)-diacrylate-ß-5-hydroxyamylamine] (PEI-PDHA) and polyethylene glycol-block-poly[(1,4-butanediol)-diacrylate-ß-5-hydroxyamylamine] (PEG-PDHA) by self-assembly. The experimental results showed that in the 4T1 tumor-bearing mice models, PEI-PDHA/PEG-PDHA/PTX/siSna/siTwi) complex nanoparticles (PPSTs) raised the accumulation and retention of both PTX and siRNA in tumor after administrated intravenously, resulted in the strong inhibition of the tumor growth and metastasis simultaneously. It was found that co-delivery of siSna and siTwi had more significant anti-metastasis effect than delivering a single siRNA, as a result of simultaneously inhibiting the motility of cancer cells and degradation of ECM. Therefore, PPSTs could be a promising co-delivery vector for effective therapy of metastatic breast cancer.

Codelivery of sorafenib and curcumin by directed self-assembled nanoparticles enhances therapeutic effect on hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related mortality worldwide. Herein, we first reported the codelivery of sorafenib and curcumin by directed self-assembled nanoparticles (SCN) to enhance the therapeutic effect on HCC. SCN was formed by employing the hydrophobic interactions among the lipophilic structure in sorafenib, curcumin, and similar hydrophobic segments of polyethylene glycol derivative of vitamin E succinate (PEG-VES), which comprised uniform spherical particles with particle size of 84.97 ± 6.03 nm. SCN presented superior effects over sorafenib, curcumin, and their physical mixture (Sora + Cur) on enhancing in vitro cytotoxicity and cell apoptosis in BEL-7402 cells and Hep G2 cells, and antiangiogenesis activities in tube formation and microvessel formation from aortic rings. Moreover, the tissue concentration of sorafenib and curcumin in gastrointestinal tract and major organs were significantly improved after their coassembly into SCN. In particular, in BEL-7402 cells induced tumor xenograft, SCN treatment displayed the obviously enhanced inhibitory effect on tumor progression over free drug monotherapy or their physical mixture, with significantly increased antiproliferation and antiangiogenesis capability. Thereby, the codelivered nanoassemblies of sorafenib and curcumin provided a promising strategy to enhance the combinational therapy of HCC.

Hydrophobic interaction mediating self-assembled nanoparticles of succinobucol suppress lung metastasis of breast cancer by inhibition of VCAM-1 expression.

The prevention and treatment of lung metastasis of breast cancer remain a major challenge. The vascular cell adhesion molecule-1 (VCAM-1) could provide a potential therapeutic target in lung metastasis. Herein, succinobucol (SCB), a water-insoluble potent and selective VCAM-1 inhibitor, was assembled with triblock polymer poloxamer P188 into nanoparticles due to the intermolecular hydrophobic interactions. The experimental results showed that the SCB loaded nanoparticles (SN) could greatly improve the oral delivery and suppress the lung metastasis of breast cancer. The cell migration and invasion abilities of metastatic 4T1 breast cancer cells were obviously inhibited by SN. Moreover, the VCAM-1 expression on 4T1 cells was significantly reduced by SN, and the cell-cell binding ratio of RAW 264.7 cells to 4T1 cells greatly decreased from 47.4% to 3.2%. Furthermore, the oral bioavailability of SCB was greatly improved about 13-fold by SN, and the biodistribution in major organs was evidently enhanced. In particular, in the metastatic breast cancer model, the lung metastasis was notably reduced by SN treatment, and the VCAM-1 expression in lung tissues was significantly inhibited. Thereby, SN could evoke a new effective therapeutic efficacy of SCB on lung metastasis of breast cancer by inhibition of VCAM-1 expression.

Co-delivery of doxorubicin and RNA using pH-sensitive poly (ß-amino ester) nanoparticles for reversal of multidrug resistance of breast cancer.

An appropriate co-delivery system for chemotherapeutic agents and nucleic acid drugs will provide a more efficacious approach for the treatment of breast cancer by reversing multidrug resistance (MDR). In this work, a new amphiphilic poly (ß-amino ester), poly[(1,4-butanediol)-diacrylate-ß-5-polyethylenimine]-block-poly[(1,4-butanediol)-diacrylate-ß-5-hydroxy amylamine] (PDP-PDHA) was synthesized, and the doxorubicin (DOX) and survivin-targeting shRNA (shSur) co-loading nanoparticle (PDNs) were prepared. The pH-sensitive poly[(1,4-butanediol) diacrylate-ß-5-hydroxy amylamine] (PDHA) endowed PDNs both pH-triggered drug release characteristics and enhanced endo/lysosomal escape ability, thus improving the cytotoxicity of DOX and the transfection efficiency. PDNs also increased the DOX accumulation, down-regulated 57.7% survivin expression, induced 80.8% cell apoptosis and changed the cell cycle in MCF-7/ADR cells. In the MCF-7/ADR tumor-bearing mice models, after administrated intravenously, PDNs raised the accumulation of DOX and shSur in the tumor tissue by 10.4 and 20.2 folds, respectively, resulting in obvious inhibition of the tumor growth with tumor inhibiting rate of 95.9%. The combination of DOX and RNA interference showed synergistic effect on overcoming MDR. Therefore, PDNs could be a promising co-delivery vector for effective therapy of drug resistant breast cancer.

Directed self-assembled nanoparticles of probucol improve oral delivery: fabrication, performance and correlation.

PURPOSE: We are reporting on the development of a unique drug delivery platform by directed self-assembly technique to improve the oral delivery of hydrophobic drugs. METHODS: Herein, a series of probucol directed self-assembled nanoparticles (PDN) were developed with two components of probucol and surfactant such as Tween 20, Tween 80, D-alpha-tocopheryl polyethylene glycol 1,000 succinate (TPGS) and HS-15, which was respectively named as T20-PDN, T80-PDN, TP-PDN and HS-PDN. The formation of various PDNs was determined by in vitro characterization and the physicochemical properties of these PDNs were determined. Moreover, the performance of PDN in enhancing the oral delivery and possible correlation between the in vitro properties and in vivo performances were investigated. RESULTS: PDN was homogenous nanometer-sized particles with negative surface charge. The cellular uptake of probucol in Caco-2 cell monolayer was respectively increased 1.15, 1.82, 1.59 and 5.31-fold by these PDN. In particular, the oral bioavailability of these PDN was significantly improved 3.0, 4.1, 5.4 and 10.4 folds compared with the free drug suspension. The enhanced cellular uptake and oral bioavailability were correlated with the characters of involved surfactants and the particle size of PDN. CONCLUSIONS: Thereby, the directed self-assembled nanoparticles could provide a new strategy for enhancing the oral delivery of hydrophobic drugs.

Effective delivery of p65 shRNA by optimized Tween 85-polyethyleneimine conjugate for inhibition of tumor growth and lymphatic metastasis.

To maximize the interference efficacy of pGPU6/Neo-p65 shRNA-expressing pDNA (p65 shRNA) and subsequently more effectively inhibit tumor growth and lymphatic metastasis through blocking the nuclear factor-kappa B (NF-κB) signaling pathway, seven Tween 85-polyethyleneimine (PEI) conjugates (TnPs, n=2, 3, 4, 5, 6, 7 and 8), which differed in the length of the polymethylene [-(CH2)n-] spacer between Tween 85 and PEI, were synthesized and investigated. The results showed that the transfection efficiency and cytotoxicity both increased with the spacer chain length. Then, TnPs with a [-(CH2)6-] spacer (T6P) were chosen to deliver p65 shRNA to a tumor and subsequently inhibit tumor growth and lymphatic metastasis. The T6P/p65 shRNA complex nanoparticles (T6Ns) could significantly down-regulate p65 expression in breast cancer cells, and consequently inhibit cell invasion and disrupt the tube formation. Most importantly, T6Ns accumulated greatly in tumor tissue, and as a result, significantly inhibited the growth and lymphatic metastasis of breast cancer xenograft. All these results indicated that the transfection efficacies of cationic amphiphiles could be significantly modulated by minor structural variations, and that T6P was promising for the effective delivery of p65 shRNA to knock down the expression of the key metastasis-driving genes and inhibit tumor growth and metastasis.

Multifunctional nanoparticles improve therapeutic effect for breast cancer by simultaneously antagonizing multiple mechanisms of multidrug resistance.

For efficient reversal of multidrug resistance (MDR) in chemotherapy for breast cancer, multifunctional self-assembled nanoparticles (MSN) based on a new amphiphilic copolymer consisting of bioreducible poly[bis(2-hydroxylethyl)-disulfide-diacrylate-ß-tetraethylenepentamine] and polycaprolactone (PBD-PCL) were constructed and characterized. shRNA targeting the apoptosis-inhibiting gene, Survivin, was incorporated into the nanoparticles with high RNA interference efficiency. PBD-PCL significantly inhibited the activity of P-glycoprotein, one of the most well-described drug-efflux pumps, and glutathione S-transferase, an important detoxification enzyme. MSN achieved colocalization of RNA and doxorubicin in tumors after intravenous administration and showed remarkable antitumor efficacy in MDR tumor-bearing mice with less side-effect than drug combination therapy. This was a new attempt to overcome MDR against three different mechanisms of MDR simutaneously: overexpression of drug efflux protein, activation of detoxification system, and blockage of apoptosis. These results indicated that the PBD-PCL-based MSN had obvious potential for therapy of breast cancer.

A high-drug-loading self-assembled nanoemulsion enhances the oral absorption of probucol in rats.

The purpose of this study was to develop a high-drug-loading nanoemulsion by self-assembly to improve the oral absorption of high dosing poorly water-soluble drugs. Probucol was selected as a model drug and the probucol-loaded self-assembled nanoemulsion (PSN) was prepared and characterized. Moreover, the intestinal absorption and in vivo pharmacokinetic behavior of PSN were evaluated in rats after oral administration. The experimental results indicated that PSN was nanometer-sized droplets with the mean diameter of 40.32 ± 0.31 nm and polydispersity index of 0.184 ± 0.005. The aqueous solubility of probucol was remarkably increased after its incorporation into PSN. Compared with free drug suspension, the intestinal absorption of PSN was not significantly increased in duodenum, but obviously enhanced 3.62- and 13.1-fold in jejunum and ileum, respectively. In particular, the in vivo pharmacokinetic results indicated that the oral bioavailability of probucol was greatly improved 8.97-fold by PSN. Thereby, the high-drug-loading self-assembled nanoemulsion was very effective in enhancing the oral absorption of high-dosing poorly water-soluble drugs.

Induction of apoptosis in non-small cell lung cancer by downregulation of MDM2 using pH-responsive PMPC-b-PDPA/siRNA complex nanoparticles.

Non-small cell lung cancer (NSCLC) accounts for the majority of lung cancer caused human death. In this work, we selected oncogene mouse double minute 2 (MDM2) as a therapeutic target for NSCLC treatment and proposed that sufficient MDM2 knockdown could inhibit tumor growth via induction of cell cycle arrest and cancer cell apoptosis. On this regard, a new pH-responsive diblock copolymer of poly(methacryloyloxy ethyl phosphorylcholine)-block-poly(diisopropanolamine ethyl methacrylate) (PMPC-b-PDPA)/siRNA-MDM2 complex nanoparticle with minimized surface charge and suitable particle size was designed and developed for siRNA-MDM2 delivery in vitro and in vivo. The experimental results showed that the nanoparticles were spherical with particle size around 50 nm. MDM2 knockdown in p53 mutant NSCLC H2009 cells induced significant cell cycle arrest, apoptosis and growth inhibition through upregulation of p21 and activation of caspase-3. Furthermore, the growth of H2009 xenograft tumor in nude mice was inhibited via repeated injection of PMPC-b-PDPA/siRNA-MDM2 complex nanoparticles. These results suggested that PMPC-b-PDPA/siRNA complex nanoparticles targeting a unique set of oncogenes could be developed into a new therapeutic approach for NSCLC treatment.

Porous starch based self-assembled nano-delivery system improves the oral absorption of lipophilic drug.

The therapeutic efficacy of lipophilic drugs is commonly restricted by the low systemic exposure after oral administration. In this work, a new delivery system combining the advantages of porous starch and self-assembled nanocarrier was designed to improve the oral absorption of lipophilic drugs. The lipophilic probucol loaded porous starch based self-assembled nano-delivery (PSN) system was developed and characterized. The probucol loaded nanocarrier (PLN) could be formed by self-assembly when PSN was dispersed into the gastrointestinal (GI) fluids. PLN was nanometer-sized particles with narrow size distribution and exhibited good stability in GI fluids. The aqueous solubility of probucol was increased over 50,000-fold by PSN delivery system and the cumulative release of lipophilic probucol was increased over 80% in GI fluids. The distribution of probucol in duodenum, jejunum and ileum was respectively improved 7.17, 15.99 and 33.61-fold by PSN. In particular, the oral bioavailability of probucol from PSN was greatly improved about 9.96-fold than that from free drug suspension and 3.71-fold higher than that from the directed adsorbed probucol loaded porous starch system, which effectively confirmed the high potential of the strategy in enhancing the oral absorption of lipophilic drugs.

Overcoming multidrug resistance by co-delivery of Mdr-1 and survivin-targeting RNA with reduction-responsible cationic poly(ß-amino esters).

Multidrug resistance (MDR) remains one of the main challenges in the successful chemotherapy of human cancer. RNA interference (RNAi) strategy aiming at only one cause of MDR was widely applied, nevertheless hardly obtained satisfactory tumor-suppressing effect. In this work, a new attempt to package two kinds of RNA with different functions into one vector and reverse MDR against two different mechanisms via RNAi was carried out. A new bioreducible poly (ß-amino esters) (PAEs), poly[bis(2-hydroxylethyl)-disulfide-diacrylate-ß-tetraethylenepentamine] (PAP) was synthesized by Michael addition reaction. The PAEs/RNA complex nanoparticles (PAEN) were prepared. The experimental results demonstrated that co-delivery of iMdr-1-shRNA and iSurvivin-shRNA could be achieved by a single vector, and interfering two genes simultaneously had a synergistic effect on overcoming MDR. PAEN lowered the IC(50) value of doxorubicin (DOX) in MDR tumor cells to a comparable level to that in the sensitive cell line through down-regulating the expression of P-gp and Survivin, and decreased the tumor volumes in mice xenograft model bearing DOX-resistant human breast cancer when combined with DOX. These results illustrated that PAEN could be applied as potential efficient non-viral RNA carriers for reversing MDR.

A self-assembled nanodelivery system enhances the oral bioavailability of daidzein: in vitro characteristics and in vivo performance.

AIM: A self-assembled nano-based delivery system was designed and developed to increase the oral bioavailability of poor hydrophilic and lipophilic daidzein. METHODS: Daidzein was firstly combined with lecithin to form the daidzein-lecithin complex, then self-assembled into micelles (DLMs) with lecithin and sodium bile. The physiochemical properties and intestinal absorption of DLMs were characterized, and the pharmacokinetic behavior was evaluated in rats. RESULTS: DLMs exhibited nanometer-sized particles. DLMs were mainly distributed in the stomach and proximal intestine after oral administration. The intestinal absorption of DLMs was significantly improved, and DLMs could be absorbed via both endocytosis and passive transport. The AUC(0-t) value of daidzein in rats treated with DLMs was ninefold greater than that of free daidzein suspension. CONCLUSION: The presented delivery system could provide a new promising strategy for enhancing the oral bioavailability of drugs with poor hydrophilicity and lipophilicity.

Daidzein-phospholipid complex loaded lipid nanocarriers improved oral absorption: in vitro characteristics and in vivo behavior in rats.

A nano-based delivery system was developed to improve the oral absorption of daidzein, which has poor hydrophilicity and lipophilicity. A daidzein-phospholipid complex (DPC) was firstly prepared to improve its lipophilicity, and then encapsulated into lipid nanocarriers (DLNs) to verify the effectiveness of the strategy in enhancing the oral delivery of daidzein. DLNs were spherical nanosized particles with evidently increased dissolution. DLNs were mainly distributed in stomach and proximal intestine of mice after oral administration, and the intestinal permeability of DLNs in rats was significantly improved when compared with that of daidzein solution. The peak concentration of daidzein in rats after oral administration of DPC and DLNs was 6833 ± 1112 ng mL(-1) and 14,512 ± 2390 ng mL(-1), respectively, which was improved over 10-fold and 21-fold than that of free daidzein. Moreover, the areas under the concentration-time curve (AUC(0-t)) of DPC and DLNs were enhanced by 3.62-fold and 6.87-fold compared with that of free daidzein. These results suggested that DLNs could be an effective strategy to improve the oral absorption of poor hydrophilic and lipophilic drugs like daidzein.

Linear cationic click polymer for gene delivery: synthesis, biocompatibility, and in vitro transfection.

Sixteen novel cationic click polymers (CPs) were parallelly synthesized via the conjugation of four alkyne-functionalized monomers to four azide-functionalized monomers by "click chemistry". The biocompatibility of CPs was evaluated by in vitro cytotoxicity (MTT assay, Hoechst/PI apoptosis/necrosis assay, and cell cycle analysis) and blood compatibility tests (hemolysis and erythrocyte aggregation). The experimental results showed that the kind of amine groups, charge density, and number of methylene or ethylene glycol groups brought about the effect on toxicity of CPs. Among all polymers, two polymers (B1 and B2) showed good biocompatibility, inducing neither apoptosis nor necrosis at the test concentration and low hemolysis ratio and erythrocyte aggregation. In particular, B1 and B2 exhibited the comparable transfection efficiency compared with PEI (25 kDa) but much lower cytotoxicity. These results suggested that the novel cationic CPs could be promising carriers for gene delivery.

Galactosylated poly(2-(2-aminoethyoxy)ethoxy)phosphazene/DNA complex nanoparticles: in vitro and in vivo evaluation for gene delivery.

To achieve efficient gene delivery to the tumor after intravenous administration, biodegradable poly(2-(2-aminoethyoxy)ethoxy)phosphazene (PAEP) was modified by lactobionic acid, bearing a galactose group as a targeting ligand. Galactosylated poly(2-(2-aminoethyoxy)ethoxy)phosphazene (Gal-PAEP) with 4.9% substitution degree of galactose could condense pDNA into nanoparticles with a size around 130 nm at the polymer/DNA ratio (N/P) of 2-40. For BEL-7402 cells, the in vitro transfection efficiency of gal-PAEP/DNA complex nanoparticles (gal-PACNs) was much higher than that of the PAEP/DNA complex nanoparticles (PACNs). MTT assay indicated that the cytotoxicity of PACNs significantly decreased after conjugating with the galactose moiety. Gal-PACNs displayed the selective gene expression in the tumor and liver with relatively low gene expression in the lung or other organs compared with PACNs. These results suggested that gal-PACNs could be a promising targeting gene carrier to deliver a therapeutic gene in future.

Urocanic acid improves transfection efficiency of polyphosphazene with primary amino groups for gene delivery.

The biodegradable cationic poly(2-(2-aminoethoxy)ethoxy)phosphazene (PAEP) bearing primary amino groups and a new PAEP derivative, urocanic acid (UA) modified PAEP (UA-PAEP), were synthesized and investigated for gene delivery. The results indicated that PAEP was able to condense DNA into complex nanoparticles with the size around 120 nm at the polymer/DNA ratio (N/P) of 35, at which PAEP/DNA complex nanoparticles (PACNs) showed efficient transfection activity in complete medium. After conjugating with UA at the substitution degree of 7% (UA-PAEP7), UA-PAEP7/DNA complex nanoparticles (UP7CNs) exhibited higher transfection efficiency than PACNs and UA-PAEP25/DNA complex nanoparticles (UP25CNs) and much lower cytotoxicity compared with PEI/DNA complex nanoparticles (PEICNs). The transfection experiment using a proton pump inhibitor suggested that the gene expression of PACNs and UP-PAEP/DNA complex nanoparticles (UPCNs) was dependent on the endosomal acidification process. The acetate solution (20 mM, pH5.7) improved the transfection activity of UP7CNs in HeLa and COS 7 cell lines, which was almost comparable to PEICNs at the N/P ratio of 35. Therefore, the results suggested that UP7CNs could be a promising carrier for gene delivery.