Semaglutide ameliorates pressure overload-induced cardiac hypertrophy by improving cardiac mitophagy to suppress the activation of NLRP3 inflammasome.

Pathological cardiac hypertrophy is an important cause of heart failure(HF). Recent studies reveal that glucagon-like peptide-1 receptor (GLP1R) agonists can improve mortality and left ventricular ejection fraction in the patients with type 2 diabetes and HF. The present study aims to investigate whether semaglutide, a long-acting GLP1R agonist, can ameliorate cardiac hypertrophy induced by pressure overload, and explore the potential mechanism. The rats were performed transverse aortic constriction (TAC) to mimic pressure overload model. The rats were divided into four groups including Sham, TAC, TAC + semaglutide, and TAC + semaglutide + HCQ (hydroxychloroquine, an inhibitor of mitophagy). The rats in each experimental group received their respective interventions for 4 weeks. The parameters of left ventricular hypertrophy(LVH) were measured by echocardiography, Hematoxylin-eosin (HE) staining, western-blot and immunohistochemistry (IHC), respectively. The changes of mitophagy were reflected by detecting cytochrome c oxidase subunit II (COXII), LC3II/LC3I, mitochondria, and autophagosomes. Meanwhile, NLRP3, Caspase-1, and interleukin-18 were detected to evaluate the activation of NLRP3 inflammasome in each group. The results suggest that LVH, impaired mitophagy, and activation of NLRP3 inflammasome were present in TAC rats. Semaglutide significantly reduced LVH, improve mitophagy, and down-regulated NLRP3 inflammatory signal pathway in TAC rats. However, the reversed effect of semaglutide on cardiac hypertrophy was abolished by HCQ, which restored the activation of NLRP3 inflammasome suppressed by improved mitophagy. In conclusion, semaglutide ameliorates the cardiac hypertrophy by improving cardiac mitophagy to suppress the activation of NLRP3 inflammasome. Semaglutide may be a novel potential option for intervention of cardiac hypertrophy induced by pressure overload.

Hydrogel-mediated tumor T cell infiltration and immune evasion to reinforce cancer immunotherapy.

Cancer immunotherapy has received increasing attention in tumor therapy. However, insufficient infiltration of T cells and over-expressed PD-L1 checkpoint in tumor cells severely impede cancer immunotherapy. Here, an injectable hydrogel was designed to reinforce T cell infiltration and inactivate PD-L1 for powerful cancer immunotherapy. The hydrogel was created by sodium alginate (SA) as the gelator, where linagliptin particles and BMS-202 particles were present in hydrogel micropores. After gelation in the tumor site, the linagliptin powerfully suppressed chemokine CXCL10 degradation, enabling the introduced CXCL10 to realize sustainable chemotaxis towards strong T cell infiltration. Meanwhile, the BMS-202 inactivated PD-L1 of tumor cells, thereby eliminating the PD-L1-governed immune evasion. Therefore, the hydrogel in combination with CXCL10 demonstrated powerful cancer immunotherapy against primary and distant tumors, along with efficient inhibition of lung metastasis. Our study not only offers a potent platform against tumors, but also provides a conceptually new approach to reinforce cancer immunotherapy.

A photodynamic-mediated glutamine metabolic intervention nanodrug for triple negative breast cancer therapy.

"Glutamine addiction" is a unique feature of triple negative breast cancer (TNBC), which has a higher demand for glutamine and is more susceptible to glutamine depletion. Glutamine can be hydrolyzed to glutamate by glutaminase (GLS) for synthesis of glutathione (GSH), which is an important downstream of glutamine metabolic pathways in accelerating TNBC proliferation. Consequently, glutamine metabolic intervention suggests potential therapeutic effects against TNBC. However, the effects of GLS inhibitors are hindered by glutamine resistance and their own instability and insolubility. Therefore, it is of great interest to harmonize glutamine metabolic intervention for an amplified TNBC therapy. Unfortunately, such nanoplatform has not been realized. Herein, we reported a self-assembly nanoplatform (BCH NPs) with a core of the GLS inhibitor Bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl) ethyl sulfide (BPTES) and photosensitizer Chlorin e6 (Ce6) and a shell of human serum albumin (HSA), enabling effective harmonization of glutamine metabolic intervention for TNBC therapy. BPTES inhibited the activity of GLS to block the glutamine metabolic pathways, thereby inhibiting the production of GSH to amplify the photodynamic effect of Ce6. While Ce6 not only directly killed tumor cells by producing excessive reactive oxygen species (ROS), but also deplete GSH to destroy redox balance, thus enhancing the effects of BPTES when glutamine resistance occurred. BCH NPs effectively eradicated TNBC tumor and suppressed tumor metastasis with favorable biocompatibility. Our work provides a new insight for photodynamic-mediated glutamine metabolic intervention against TNBC.

Allergic contact stomatitis due to desensitizing toothpastes.

Toothpastes are one of the most common personal care products among people of all ages. The various toothpaste types and their complex ingredients could cause irritation or allergic reactions. Allergic contact stomatitis has been often seen in clinical practice; however, desensitizing toothpastes as a trigger are often unrecognized. Here, we report three cases of allergic contact stomatitis due to stannous chloride-containing desensitizing toothpastes. General dentists and other professionals should pay more attention to the safety and adverse effects of toothpastes.

Direct immunofluorescence analysis of oral Tzanck smears for pemphigus vulgaris: A diagnostic test.

BACKGROUND: Pemphigus vulgaris (PV) is a rare and potentially fatal autoimmune blistering disease. Direct immunofluorescence (DIF) and histopathological analysis are crucial methods for PV diagnosis, but oral tissue biopsy is difficult to perform because of the fragile characteristics of the oral mucosa. However, no well-designed diagnostic studies addressing the validity of DIF analysis of oral Tzanck smears for the diagnosis of PV exist. We aimed to design a diagnostic test based on DIF analysis combined with oral Tzanck smears and evaluate its diagnostic accuracy for PV. METHODS: We enrolled 81 patients with oral erosive lesions, of whom 41 patients had PV and 40 were non-PV controls. Oral Tzanck smears were obtained from oral mucosal lesions and observed under a fluorescence microscope after fixing and fluorescence staining. The diagnostic efficacy indexes including sensitivity, specificity, predictive value, Youden index, diagnostic odds ratio, and likelihood ratio were calculated. RESULTS: Of the 41 PV patients, 36 showed DIF-positive findings for oral Tzanck smears, and all 36 DIF-positive PV patients showed IgG and/or C3 deposition, with seven also showing IgA and/or IgM positivity. None of the non-PV controls showed DIF positivity. The sensitivity and specificity of DIF analysis with oral Tzanck smears were 87.80% and 100%, respectively. The area under the receiver operator characteristic curve (ROC) was 0.939, with the test demonstrating significantly high diagnostic efficacy. CONCLUSION: DIF analysis of oral Tzanck smears is a minimally invasive and easy-to-operate technique that can assist the rapid and accurate diagnosis of PV in dental clinic.

Pulmonary surfactants affinity Pluronic-hybridized liposomes enhance the treatment of drug-resistant lung cancer.

For a long time, the incidence and mortality of lung cancer have ranked first among all kinds of cancers, of which the major type is non-small cell lung cancer (NSCLC). Until now, chemotherapy and radiotherapy are still the first choice for patients with advanced or metastatic NSCLC. However, the emergence of multi-drug resistance (MDR) always leads to the failure of chemotherapy and increases cancer-related mortality. In this study, we prepared a Pluronic-hybridized paclitaxel-loaded liposome (PPL), which was used in combination with ambroxol (Ax) to not only resensitize drug-resistant tumor cells, but also increase the preparation retention in the lung. On the one hand, Ax induced the production of pulmonary surfactants (PS) and responsively improved the accumulation of pulmonary surfactants affinity liposomes whose skeleton was exogenous pulmonary surfactant phospholipids DPPC, because of the specific affinity of phospholipids related to pulmonary surfactant proteins. On the other hand, drug-resistant tumor cells were resensitized due to the inhibition of autophagy by Ax and the reduced expression of the drug-resistant protein P-glycoprotein (P-gp) by Pluronic P105. Therefore, we concluded that the combination of PPL and Ax achieved excellent killing tumor effects through multi-path and multi-strategy, having great application prospects in the future.

Preferential Targeting Cerebral Ischemic Lesions with Cancer Cell-Inspired Nanovehicle for Ischemic Stroke Treatment.

The poor drug delivery to cerebral ischemic regions is a key challenge of ischemic stroke treatment. Inspired by the intriguing blood-brain barrier (BBB)-penetrating ability of 4T1 cancer cells upon their brain metastasis, we herein designed a promising biomimetic nanoplatform by camouflaging a succinobucol-loaded pH-sensitive polymeric nanovehicle with a 4T1 cell membrane (MPP/SCB), aiming to promote the preferential targeting of cerebral ischemic lesions to attenuate the ischemia/reperfusion injury. In transient middle cerebral artery occlusion (tMCAO) rat models, MPP/SCB could be preferentially delivered to the ischemic hemisphere with a 4.79-fold higher than that in the normal hemisphere. Moreover, MPP/SCB produced notable enhancement of microvascular reperfusion in the ischemic hemisphere, resulting in a 69.9% reduction of infarct volume and showing remarkable neuroprotective effects of tMCAO rats, which was superior to the counterpart uncamouflaged nanovehicles (PP/SCB). Therefore, this design provides a promising nanoplatform to target the cerebral ischemic lesions for ischemic stroke therapy.

Pulmonary-Affinity Paclitaxel Polymer Micelles in Response to Biological Functions of Ambroxol Enhance Therapeutic Effect on Lung Cancer.

PURPOSE: Cancer chemotherapy effect has been largely limited by cell autophagy and little drug accumulation at the action sites. Herein, we designed an intelligent strategy involving paclitaxel (PTX) polymer micelles in response to biological functions of ambroxol (Ax). The amphiphilic polymers polyethyleneglycol-polylactic acid (PEG-PLA) and Pluronic P105 were selected as nanocarriers to encapsulate PTX to form into lung affinity PEG-PLA/P105/PTX micelles. Ax which can up-regulate the secretion of pulmonary surfactant (PS) and inhibit autophagy was hired to change the microenvironment of the lung, thereby promoting the lung accumulation and increasing cell-killing sensitivity of the micelles. METHODS: The physical and chemical properties of the micelles were characterized including size, morphology, critical micellar concentration (CMC) and in vitro drug release behavior. The therapeutic effects of the combination regimen were characterized both in vitro and in vivo including study on Ax in promoting the secretion of pulmonary surfactant, in vitro cytotoxicity, cellular uptake, Western blotting, in vivo biodistribution, in vivo pharmacokinetics and in vivo antitumor efficacy. RESULTS: The PEG-PLA/P105/PTX micelles showed a particle size of 16.7 ± 0.5 nm, a nearly round shape, small CMC and sustained drug release property. Moreover, the in vitro results indicated that Ax could increase PS and LC3 protein secretion and enhance the cytotoxicity of PEG-PLA/P105/PTX micelles toward A549 cells. The in vivo results indicated that the combination therapeutic regimen could promote the micelles to distribute in lung and enhance the therapeutic effect on lung cancer. CONCLUSION: This multifunctional approach of modulating the tumor microenvironment to enhance drug transportation and cell-killing sensitivity in the action sites might offer a new avenue for effective lung cancer treatment.

A carbohydrate mimetic peptide modified size-shrinkable micelle nanocluster for anti-tumor targeting and penetrating drug delivery.

PURPOSE: To deliver the chemotherapeutics through the nanoparticles, the delivery system should accumulate at the tumor site first and then penetrate through the interstitium into the interior. The specific tumor-targeting pathway mediated via the receptor-ligand binding could achieve the desirable accumulation of nanoparticles, and the nanoparticles with smaller sizes were required for penetration. METHODS AND MATERIALS: We constructed a size-shrinkable nanocluster modified with a tumor-targeting motif IF-7 (IF-7-MNC) based on a pH-sensitive framework which could be disintegrated in an acid environment to release the micelles aggregated inside. The micelles were constructed by amphiphilic block copolymers PEG-PLA to encapsulate paclitaxel (PTX), while the cross-linked framework consisting of TPGS-PEI was used as a net to gather and release micelles. This nanoplatform could specifically bind with the tumor receptor Annexin A1 through the ligand IF-7 and then shrunk into small micelles with a desirable size for penetration. CONCLUSION: IF-7-MNC of 112.27±6.81 nm could shrink into micelles in PBS (0.01 M, pH 5.0) with sizes of 14.89±0.32 nm. The cellular-uptake results showed that IF-7-MNC could be significantly internalized by A549 cells and HUVEC cells, while the penetration of IF-7-MNC could be more prominent into the 3D-tumor spheroids compared with that of MNC. The biodistribution results displayed that the fluorescence of IF-7-MNC in the tumor site at 24 hrs was 4.5-fold stronger than that of MNC. The results of anti-tumor growth demonstrated that IF-7-MNC was more favorable for the tumor therapy than MNC, where the inhibitory rate of tumor growth was 88.29% in the PTX-loaded IF-7-MNC (IF-7-PMNC) treated group, significantly greater than PMNC treatment group (p<0.05).

Leukocyte-mimicking Pluronic-lipid nanovesicle hybrids inhibit the growth and metastasis of breast cancer.

Breast cancer is a severe threat to the health of women, and the metastasis of tumor cells leads to high mortality in female patients. Evidence shows that leukocytes are recruited by breast tumors through adhesion to inflammatory endothelial cells as well as tumor cells. Moreover, it is known that Pluronic P123 is effective in the reduction of matrix metalloproteinases (MMPs), which play a key role in the degradation of the extracellular matrix (ECM), therefore helping tumor cells to escape from the primary site. Inspired by these mechanisms, we established a leukocyte-mimicking Pluronic-lipid nanovesicle hybrid (LPL) through integrating the membrane proteins extracted from leukocytes with membrane-like vesicles, with Pluronic P123 hybridized in the lipid bilayer, while paclitaxel (PTX) was selected as the model drug. The hybrid vesicles were perfectly incorporated with the leukocyte membrane proteins, and no disruption to the lipid membrane was caused by P123, with the bio-targeting ability of leukocytes and the MMP-9-downregulation effect of P123 fully preserved in LPL. LPL exhibited enhanced cellular uptake and anti-metastasis efficacy in in vitro assays, while significant tumor targeting capabilities were also found through biodistribution assays. Moreover, the in vivo therapeutic effects of PTX-loaded LPL (PTX-LPL) were observed, with an 80.84% inhibition rate of tumor growth and a 10.62% metastatic rate of tumor foci in lung tissue. Furthermore, the amounts of MMP-9 and neutrophils in the tumor as well as in the lung were greatly reduced with PTX-LPL. In summary, LPL may have potential applications in metastatic breast cancer therapy.

Rapamycin-mediated mTOR inhibition impairs silencing of sex chromosomes and the pachytene piRNA pathway in the mouse testis.

Mechanistic target of rapamycin (mTOR) controls cell growth and metabolism in response to environmental and metabolic signals. Rapamycin robustly extends the lifespan in mammals and has clinical relevance in organ transplantation and cancer therapy but side effects include male infertility. Here, we report that chronic rapamycin treatment causes spermatogenic arrest in adult male mice due to defects in sex body formation and meiotic sex chromosome inactivation (MSCI). Many sex chromosome-linked genes were up-regulated in isolated pachytene spermatocytes from rapamycin-treated mice. RNA-Seq analysis also identified mRNAs encoding the core piRNA pathway components were decreased. Furthermore, rapamycin treatment was associated with a drastic reduction in pachytene piRNA populations. The inhibitory effects of rapamycin on spermatogenesis were partially reversible, with restoration of testis mass and sperm motility within 2 months of treatment cessation. Collectively, we have defined an essential role of mTOR in MSCI and identified a novel function as a regulator of small RNA homeostasis in male germ cells.

A versatile strategy to create an active tumor-targeted chemo-photothermal therapy nanoplatform: A case of an IR-780 derivative co-assembled with camptothecin prodrug.

Self-assembled nanovehicles of chemotherapy drug with photothermal agent are regarded as intriguing chemo-photothermal therapy nanoplatform. However, most of the drugs and photothermal agents have poor water solubility and poor interactions to drive the formation of self-assembled nanovehicles, which is a bottleneck of co-assembled drug/photothermal agent for cancer therapy. Here, we proposed a versatile strategy to create self-assembled chemo-photothermal therapy nanoplatform based on the chemical modification of photothermal agent and drug. The IR-780 and camptothecin (CPT) were chosen as the studied models since they are important photothermal agent and anticancer drug, both of which have such poor water solubility with strong itself molecular interactions that they cannot co-assemble together. IR-780 was modified with an active targeting ligand lactobionic acid (LA) to result in amphiphilic IR780-LA while CPT was modified into redox-sensitive prodrug CPT-ss-CPT through a disulfide linkage to realize its assembly. Well-defined nanoparticles (NPs) could be created through the co-assembling of IR780-LA and CPT-ss-CPT. The IR780-LA/CPT-ss-CPT nanoparticles were demonstrated to be an excellent fluorescence imaging-guided, redox-responsive and enhanced synergistic chemo-photothermal therapy nanoplatform against tumors. Specifically, our chemical modification strategy offers a universal way to create self-assembled chemo-photothermal therapy nanoplatform, which solves the bottleneck of co-assembled drug/photothermal agent for cancer therapy. STATEMENT OF SIGNIFICANCE: Self-assembled nanoparticles of chemotherapeutics with photothermic drugs are regarded as intriguing chemo-photothermal therapy nanoplatform. However, most drugs have too poor solubility and interactions to form into self-assembled nanoparticles. We proposed a versatile strategy to create co-assembled chemo-photothermal therapy nanoparticles based on the chemical modification of common drugs. The IR-780 was modified with an active targeting ligand LA to result in amphiphilic IR780-LA molecules, while CPT was modified into redox-sensitive prodrug CPT-ss-CPT through disulfide linkage. Well-defined IR780-LA/CPT-ss-CPT nanoparticles were created through the co-assembling of IR780-LA and CPT-ss-CPT. The nanoparticles were demonstrated to be an excellent fluorescence imaging-guided, redox-responsive, active targeting chemo-photothermal therapy nanoplatform against tumors. Our strategy offers a versatile way to construct smart chemo-photothermal therapy nanoplatform from common drugs.

Rational Design of a New Self-Codelivery System from Redox-Sensitive Camptothecin-Cytarabine Conjugate Assembly for Effectively Synergistic Anticancer Therapy.

Herein, two careful selected anticancer drugs camptothecin (CPT) and cytarabine (Ara-C) with different biological action mechanisms and different water solubility are conjugated together through a glutathione (GSH) cleavable disulfide bond to construct a redox-sensitive drug-drug conjugate, which can self-assemble into nanoparticles, thus notably improving the water solubility of CPT and the cell membrane permeability of Ara-C. Compared with free drugs, the self-assembled CPT-ss-Ara nanoparticles can concentrate in tumor tissues through the enhanced permeability and retention (EPR) effect, then they can be rapidly internalized by tumor cells and degrade into free drugs for killing the tumor cells when exposed to the reductive environment (GSH) of tumor cells, thereby reducing the injury to normal cells. Meanwhile, the CPT-ss-Ara nanoparticles can effectively protect CPT and Ara-C molecules from biological inactivation before their arrival in tumor microenvironment since free CPT and Ara-C are easy to partly lose their therapy efficacy due to their structure degradation in blood circulation. The in vitro and in vivo anticancer experimental results indicate that simultaneous release of free CPT and Ara-C can realize synergistic chemotherapy effects, thus markedly improve their anticancer activity. Therefore, our designed carrier-free, redox-sensitive CPT-ss-Ara nanoparticles might have promising clinical application to combat cancers.

Co-delivery of docetaxel and verapamil by reduction-sensitive PEG-PLGA-SS-DTX conjugate micelles to reverse the multi-drug resistance of breast cancer.

The clinical usage of docetaxel (DTX) has been blocked in the clinic because of its poor solubility and tumour multi-drug resistance (MDR). The dominating mechanism of MDR is the over-expression of p-gp on tumour cells. Traditional nano-medicines, such as nanoparticles and micelles, have been used to physically entrap DTX to improve their solubility, while the drug loading content was very low and the tumour resistance was neglected. In this study, the synthesized reduction-sensitive mPEG-PLGA-SS-DTX conjugate was utilized to load the p-gp inhibitor veraparmil (VRP) to prepare DTX and VRP co-delivered mPEG-PLGA-SS-DTX/VRP (PP-SS-DTX/VRP) multi-functional micelles to reverse MDR and enhance the anti-tumour effect of DTX. The micelles had a high drug loading content and showed an obvious reduction-sensitive release property for both DTX and VRP. In addition, an in vitro anti-tumour assay revealed that the micelles markedly inhibited the efflux activity of p-gp and accelerated cell apoptosis, resulting in the improvement of anti-tumour activity and reversal of MDR. The PP-SS-DTX micelles markedly enhanced the in vivo circulation time and increased the drug accumulation in tumour tissues. Therefore, the PP-SS-DTX/VRP micelle is a desirable drug delivery system for multi-drug resistance therapy of DTX and is very promising for clinical usage.

Nanoassemblies from amphiphilic cytarabine prodrug for leukemia targeted therapy.

The anti-leukemia effect of cytarabine (Ara-C) is severely restricted by its high hydrophilic properties and rapid plasma degradation. Herein, a novel amphiphilic small molecular prodrug of Ara-C was developed by coupling a short aliphatic chain, hexanoic acid (HA) to 4-NH2 of the parent drug. Based on the amphiphilic nature, the resulting bioconjugate (HA-Ara) could spontaneously self-assemble into stable spherical nanoassemblies (NAs) with an extremely high drug loading (∼71wt%). Moreover, folate receptor (FR)-targeting NAs with high grafting efficient folic acid - bovine serum albumin (FA-BSA) conjugate immobilized on the surface (NAs/FA-BSA) was prepared. The results of MTT assays on FR-positive K562 cells and FR-negative A549 cells demonstrated higher cytotoxicity of HA-Ara NAs than the native drug. Especially, the IC50 values revealed that NAs/FA-BSA was 3 and 2-fold effective than non-targeted NAs after 24 and 48h treatment with K562 cells, respectively indicating FR-mediated enhanced anti-tumor efficacy. In vitro cellular uptake, larger accumulation of HA-Ara NAs were observed in comparative with the free FITC and the results further confirmed the selective uptake of NAs/FA-BSA in folate receptor enriched cancer cells. Above all, self-assembled HA-Ara NAs exhibited potential superiority for Ara-C delivery and FA-modified NAs would be an excellent candidate for targeting leukemia therapy.

Folic acid-grafted bovine serum albumin decorated graphene oxide: An efficient drug carrier for targeted cancer therapy.

Targeting drug carrier systems based on graphene oxide (GO) are of great interest, since it can selectively deliver anticancer drugs to tumor cells, and enhance therapeutic activities with minimized side effects. However, direct grafting target molecules on GO usually results in aggregation of physiological fluid, limiting its biomedical applications. Here, we propose a new strategy to construct targeting GO drug carrier using folic acid grafted bovine serum albumin (FA-BSA) as both the stabilizer and targeting agent. FA-BSA decorated graphene oxide-based nanocomposite (FA-BSA/GO) was fabricated by the physical adsorption of FA-BSA on GO, which was developed as a targeting drug delivery carrier. FA-BSA/GO as the drug carrier was associated with anticancer drug doxorubicin (DOX) through π-π and hydrogen-bond interactions, resulting in high drug loading (up to 437.43µgDOX/mgFA-BSA/GO). FA-BSA/GO/DOX systems demonstrated pH responsive and sustained drug release. The hemolysis ratio of FA-BSA/GO was less than 5%, demonstrating its safety as drug carrier for intravenous injection. Moreover, in vitro cell cytotoxicity and cellular uptake analysis suggested that the constructed FA-BSA/GO/DOX nanohybrids could significantly enhance the anticancer activity. The present work has confirmed the potential for fabrication of highly stable and dispersible GO-based targeting delivery systems for efficient cancer therapy.

Redox-sensitive mPEG-SS-PTX/TPGS mixed micelles: An efficient drug delivery system for overcoming multidrug resistance.

The main cause of multidrug resistance (MDR) is overexpression of active efflux transporters, such as P-glycoprotein (P-gp). To reverse MDR and improve the chemotherapy effect of paclitaxel (PTX), we propose a new drug delivery system based on mixed micelles constructed with d-α-tocopheryl poly(ethylene glycol) 1000 succinate (TPGS) and the mPEG-SS-PTX conjugate with consideration that TPGS is a P-gp inhibitor that can block the cancer cell action of pumping drugs outside of cells and can enhance the anticancer effect. mPEG-SS-PTX is synthesized by conjugating hydrophilic mPEG with a hydrophobic drug, PTX, via a redox-sensitive disulfide bond. The mPEG-SS-PTX conjugate is amphiphilic and can self-assemble in water. Mixed micelles formed by the mPEG-SS-PTX conjugate and TPGS have a low critical micelle concentration (CMC, ∼1.05×10-3mg/mL) and high drug loading content (∼19.6%). The disulfide bond in the mPEG-SS-PTX conjugate can be broken in cancer cells (a reductive environment) and release PTX to kill cancer cells. In vitro cytotoxicity and cell uptake suggest that mixed micelles can effectively improve the accumulation of PTX in multidrug-resistant MCF-7 cells. Therefore, the present as-prepared mixed micelles very effectively reverse the MDR and enhance the therapeutic effect.

Redox-sensitive micelles assembled from amphiphilic mPEG-PCL-SS-DTX conjugates for the delivery of docetaxel.

Docetaxel (DTX) can produce anti-tumor effects by inhibiting cell growth and inducing apoptosis. However, the poor solubility of DTX restricts its application and its clinical formulation has caused serious adverse reaction due to the use of Tween-80. In the present study, DTX was conjugated to an amphiphilic di-block polymer to solve these problems. Methoxy poly(ethylene glycol)-poly(ε-caprolactone) (mPEG-PCL) was selected as the polymer skeleton and a redox sensitive disulfide bond was used as the linker between DTX and mPEG-PCL. The synthesized mPEG-PCL-SS-DTX conjugates were characterized by (1)H-nuclear magnetic resonance ((1)H NMR) and Fourier transform infrared spectroscopy (FTIR). Interestingly, the mPEG-PCL-SS-DTX conjugates could self-assemble into micelles in aqueous solution. The critical micelle concentration (CMC) of mPEG-PCL-SS-DTX micelles was about 2.3mgL(-1) determined using pyrene molecule fluorescent probe method while the size of mPEG-PCL-SS-DTX micelles was determined to be ca. 17.6nm and 116.0nm with a bimodal distribution by dynamic light scattering (DLS). The in vitro release results indicated that the as-prepared micelles exhibited a sustained release profile with good redox sensitive properties. In particular, the hemolytic toxicity test indicated the as-prepared mPEG-PCL-SS-DTX micelles had negligible hemolytic activity, demonstrating their safety in drug delivery system. Cytotoxicity assay of the mPEG-PCL-SS-DTX micelles verified their highly enhanced cytotoxicity to MCF-7/A and A549 cells. These results thus demonstrated that the present redox-sensitive mPEG-PCL-SS-DTX micelle was an efficient and safe sustained drug delivery system in the biomedical area.

Disulfide-Linked Amphiphilic Polymer-Docetaxel Conjugates Assembled Redox-Sensitive Micelles for Efficient Antitumor Drug Delivery.

Here, we prepared novel redox-sensitive drug delivery system based on copolymer-drug conjugates methoxy poly(ethylene glycol)-poly(γ-benzyl l-glutamate)-disulfide-docetaxel (mPEG-PBLG-SS-DTX) to realize the desirable cancer therapy. First, copolymers of methoxy poly(ethylene glycol)-poly(γ-benzyl l-glutamate) (mPEG-PBLGs) with different molecular weight (mPEG2000-PBLG1750 and mPEG5000-PBLG1750) were synthesized via the ring open polymerization (ROP) of 5-benzyl-l-glutamate-N-carboxyanhydride (γ-Bzl-l-Glu-NCA) initiated by monoamino-terminated mPEG (mPEG-NH2). Then, the docetaxel (DTX) was conjugated to the block polymers through a linkage containing disulfide bond to obtain mPEG-PBLG-SS-DTXs, including mPEG2000-PBLG1750-SS-DTX and mPEG5000-PBLG1750-SS-DTX. The obtained copolymer-drug conjugates mPEG2000-PBLG1750-SS-DTX and mPEG5000-PBLG1750-SS-DTX could self-assemble into nanosized micelles in aqueous environment via dialysis method with a low critical micelle concentration (CMC, 3.98 and 6.94 µg/mL, respectively). The size of the micelles was approximately 101.3 and 148.9 nm, respectively, with a narrow size distribution. They released approximately 40% DTX in a sustained way in the presence of 50 mM DTT after 120 h in comparison with only approximately 10% DTX released from micelles in the absence of DTT. The high cytotoxicity was identified for mPEG-PBLG-SS-DTXs micelles against MCF-7/ADR and A549 cells, and the IC50 of mPEG-PBLG-SS-DTXs micelles against MCF-7/ADR for 24 h was roughly a 15th of the value of free DTX. Moreover, the mPEG-PBLG-SS-DTXs micelles could be efficiently uptaken by MCF-7/ADR and A549 cells. Thus, the present constructed mPEG-PBLG-SS-DTXs micelles were very promising for effective cancer therapy.

Multifunctional Mixed Micelles for Efficient Docetaxol Delivery for Cancer Therapy.

The objective of this study was to build mixed micelles based on two functional co-polymers, including the redox-sensitive polymer-drug conjugate methoxy poly(ethylene glycol)-poly(γ-benzyl l-glutamate)-disulfide-docetaxel (PEG-PBLG-SS-DTX) and the actively targeting methoxy poly(ethylene glycol)-folic acid (PEG-FA), for enhanced target specificity and improved anticancer efficiency of docetaxel (DTX). The spherical PEG-PBLG-SS-DTX/PEG-FA mixed micelles prepared by the dialysis method revealed a narrowly distributed size at 129.7±2.1 nm with low polydispersity of 0.10±0.02. Furthermore, the critical micelle concentration of the mixed micelles was 5.08 µg mL-1 , indicating excellent self-assembly ability in water and stability against dilution in blood circulation. The in vitro release study revealed that the conjugated DTX was rapidly released in response to dl-dithiothreitol (DTT), a reducing agent. Only 12.3 % of DTX was released from the mixed micelles after 120 h in the absence of DTT. However, the accumulative release of DTX dramatically accelerated and reached more than 40 % in 120 h after addition of DTT. The in vitro cytotoxicity, cellular uptake and cell apoptosis experiments on the mixed micelles were performed using MTT assay, fluorescence inverted microscopy and flow cytometric analysis, and 4',6-diamidino-2-phenylindole (DAPI) staining, respectively, on folate receptor (FR)-negative A549 and FR-positive MCF-7 cells. The mixed micelles could be taken up efficiently by MCF-7 cells by FR-mediated endocytosis compared with PEG-PBLG-SS-DTX micelles. Furthermore, remarkable cytotoxicity and cell apoptosis were identified for the mixed micelles against MCF-7 cells, which was consistent with the results of the cellular uptake study. On the basis of these results, the redox-sensitive PEG-PBLG-SS-DTX/PEG-FA mixed micelles using FA as a targeting ligand revealed prominent antitumor efficiency and might be a latent drug carrier for cancer chemotherapy.