Colocalized delivery of rapamycin and paclitaxel to tumors enhances synergistic targeting of the PI3K/Akt/mTOR pathway

Identification of a Group of Therapeutic Targets and Prognostic Biomarker for Triple Negative Breast Cancer

INTRODUCTION

Triple-negative breast cancer (TNBC) is a highly heterogeneous disease. Mining differentially expressed genes of TNBC is helpful to explore new therapeutic targets. This study aimed to investigate diagnostic biomarker genes in TNBC compared to normal tissue. Additionally, we explored the functions and prognostic value of these key genes as well as potential targeted drugs that could affect these genes.

METHODS

Differential gene expression analysis was conducted using the R software with data from the Gene Expression Omnibus (GEO) database. Then, the identified differentially expressed genes (DEGs) were used to construct a protein-protein interaction (PPI) network using the Search Tool for the Retrieval of Interacting Genes (STRING) database and Cytoscape software. The mRNA expression levels of key genes were analyzed using the UALCAN database with data from The Cancer Genome Atlas (TCGA). Enrichment and survival analyses were performed using R software. In addition, potential compounds showing sensitivity to key genes were identified by gene set cancer analysis (GSCA).

RESULTS

Compared with normal tissues, a total of 203 DEGs were upregulated in TNBC. These DEGs participated in various biological processes including nuclear division, microtubule binding, cell cycle, and the p53 signaling pathway. Through the PPI network analysis, ten key genes were identified, among which four genes showed significant correlation with poor progression-free interval (PFI) in patients with TNBC. Moreover, the four survival-related genes were found to act as sensitive therapeutic targets.

CONCLUSION

The identified four key genes were considered new biomarkers for diagnosis and prognosis and also potential therapeutic targets for TNBC.

Tunable polymeric micelles for taxane and corticosteroid co-delivery

Nanomedicine holds promise for potentiating drug combination therapies. Increasing (pre)clinical evidence is available exemplifying the value of co-formulating and co-delivering different drugs in modular nanocarriers. Taxanes like paclitaxel (PTX) are widely used anticancer agents, and commonly combined with corticosteroids like dexamethasone (DEX), which besides for suppressing inflammation and infusion reactions, are increasingly explored for modulating the tumor microenvironment towards enhanced nano-chemotherapy delivery and efficacy. We here set out to develop a size- and release rate-tunable polymeric micelle platform for co-delivery of taxanes and corticosteroids. We synthesized amphiphilic mPEG-b-p(HPMAm-Bz) block copolymers of various molecular weights and used them to prepare PTX and DEX single- and double-loaded micelles of different sizes. Both drugs could be efficiently co-encapsulated, and systematic comparison between single- and co-loaded formulations demonstrated comparable physicochemical properties, encapsulation efficiencies, and release profiles. Larger micelles showed slower drug release, and DEX release was always faster than PTX. The versatility of the platform was exemplified by co-encapsulating two additional taxane-corticosteroid combinations, demonstrating that drug hydrophobicity and molecular weight are key properties that strongly contribute to drug retention in micelles. Altogether, our work shows that mPEG-b-p(HPMAm-Bz) polymeric micelles serve as a tunable and versatile nanoparticle platform for controlled co-delivery of taxanes and corticosteroids, thereby paving the way for using these micelles as a modular carrier for multidrug nanomedicine.

Paclitaxel promotes mTOR signaling-mediated apoptosis in esophageal cancer cells by targeting MUC20

BACKGROUND

The aim of this study was to analyze the effect of paclitaxel on the apoptosis of esophageal cancer cells in relation to MUC20.

METHODS

RT-qPCR analysis, a CCK-8 assay, western blotting, and flow cytometry were used to analyze the anticancer effects of paclitaxel treatment or OE-MUC20 in vitro and in vivo.

RESULTS

The in vitro results showed that paclitaxel significantly induced MUC20 upregulation and that paclitaxel treatment or OE-MUC20 significantly decreased esophageal cancer cell viability and increased mTOR signaling activation and apoptosis. In addition, PKM2, a key downstream molecule of mTOR signaling, similarly showed significant upregulation after paclitaxel treatment in cells with OE-MUC20, and its expression was attenuated after treatment with mTOR inhibitors. In a nude mouse model, tumor growth was slow in the OE-MUC20 group and accelerated after inhibition of mTOR signaling.

CONCLUSION

These data suggest that MUC20 is an important target of paclitaxel in esophageal cancer and promotes apoptosis through activation of mTOR signaling.

Ratiometric codelivery of Paclitaxel and Baicalein loaded nanoemulsion for enhancement of breast cancer treatment

The most prevalent clinical option for treating cancer is combination chemotherapy. In combination therapy, assessment and optimization for obtaining a synergistic ratio could be obtained by various preclinical setups. Currently, in vitro optimization is used to get synergistic cytotoxicity while constructing combinations. Herein, we co-encapsulated Paclitaxel (PTX) and Baicalein (BCLN) with TPP-TPGS1000 containing nanoemulsion (TPP-TPGS1000-PTX-BCLN-NE) for breast cancer treatment. The assessment of cytotoxicity of PTX and BCLN at different molar weight ratios provided an optimized synergistic ratio (1:5). Quality by Design (QbD) approach was later applied for the optimization as well as characterization of nanoformulation for its droplet size, zeta potential and drug content. TPP-TPGS1000-PTX-BCLN-NE significantly enhanced cellular ROS, cell cycle arrest, and depolarization of mitochondrial membrane potential in the 4T1 breast cancer cell line compared to other treatments. In the syngeneic 4T1 BALB/c tumor model, TPP-TPGS1000-PTX-BCLN-NE outperformed other nanoformulation treatments. The pharmacokinetic, biodistribution and live imaging studies pivoted TPP-TPGS1000-PTX-BCLN-NE enhanced bioavailability and PTX accumulation at tumor site. Later, histology studies confirmed nanoemulsion non-toxicity, expressing new opportunities and potential to treat breast cancer. These results suggested that current nanoformulation can be a potential therapeutic approach to effectively address breast cancer therapy.

Gemcitabine and rapamycin-loaded mixed polymeric thermogel for metastatic pancreatic cancer therapy

Pancreatic ductal adenocarcinoma (PDAC) is the 4th leading cause of cancer-related death and has a poor 5-year overall survival. The superior therapeutic benefits of combination or co-administration of drugs as intraperitoneal chemotherapy have increased interest in developing strategies to deliver chemotherapeutic agents to patients safely. In this study, we prepared a gel comprising the thermosensitive poly(lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PLGA-PEG-PLGA) polymer and gemcitabine (GEM), which is currently used as the primary chemotherapy for PDAC and rapamycin (RAPA), a mammalian TOR (mTOR) inhibitor, to deliver the drug through intraperitoneal injection. We performed in vitro cytotoxicity experiments to verify the synergistic effects of the two drugs at different molar ratios and characterized the physicochemical properties of the GEM, RAPA, and GEM/RAPA-loaded thermosensitive PLGA-PEG-PLGA gels, hereafter referred to as (g(G), g(R), and g(GR)), respectively. The g(GR) comprising PLGA-PEG-PLGA polymer (25% w/v) and GEM and RAPA at a molar ratio of 11:1 showed synergism and was optimized. An in vitro cytotoxicity assay was performed by treating Panc-1-luc2 tumor spheroids with g(G), g(R), or g(GR). The g(GR) treatment group showed a 2.75-fold higher inhibition rate than the non-treated (NT) and vehicle-treated groups. Furthermore, in vivo drug release assay in mice by intraperitoneal injection of g(G), g(R), or g(GR) showed a more rapid release rate of GEM than RAPA, similar to the in vitro release pattern. The drugs in the gel were released faster in vivo than in vitro and degraded in 48 h. In addition, g(GR) showed the highest anti-tumor efficacy with no toxicity to mice. These results provide evidence for the safety and efficacy of g(GR) for intraperitoneal drug delivery. This study will assist in developing and clinically administering topical anti-cancer formulations.

Endorsement of TNBC Biomarkers in Precision Therapy by Nanotechnology

Breast cancer is a heterogeneous disease which accounts globally for approximately 1 million new cases annually, wherein more than 200,000 of these cases turn out to be cases of triple-negative breast cancer (TNBC). TNBC is an aggressive and rare breast cancer subtype that accounts for 10-15% of all breast cancer cases. Chemotherapy remains the only therapy regimen against TNBC. However, the emergence of innate or acquired chemoresistance has hindered the chemotherapy used to treat TNBC. The data obtained from molecular technologies have recognized TNBC with various gene profiling and mutation settings that have helped establish and develop targeted therapies. New therapeutic strategies based on the targeted delivery of therapeutics have relied on the application of biomarkers derived from the molecular profiling of TNBC patients. Several biomarkers have been found that are targets for the precision therapy in TNBC, such as EGFR, VGFR, TP53, interleukins, insulin-like growth factor binding proteins, c-MET, androgen receptor, BRCA1, glucocorticoid, PTEN, ALDH1, etc. This review discusses the various candidate biomarkers identified in the treatment of TNBC along with the evidence supporting their use. It was established that nanoparticles had been considered a multifunctional system for delivering therapeutics to target sites with increased precision. Here, we also discuss the role of biomarkers in nanotechnology translation in TNBC therapy and management.

Challenges and opportunities in metastatic breast cancer treatments: Nano-drug combinations delivered preferentially to metastatic cells may enhance therapeutic response

Despite advances in breast cancer treatments and related 5-year survival outcomes, metastatic breast cancer cures remain elusive. The current standard of care includes a combination of surgery, radiation therapy and drug therapy. However, even the most advanced procedures and treatments do not prevent breast cancer recurrence and metastasis. Once metastasis occurs, patient prognosis is poor. Recent elucidation of the spatiotemporal transit of metastatic cancer cells from primary tumor sites to distant sites provide an opportunity to integrate knowledge of drug disposition in our effort to enhance drug localization and exposure in cancer laden tissues . Novel technologies have been developed, but could be further refined to facilitate the distribution of drugs to target cancer cells and tissues. The purpose of this review is to highlight the challenges in metastatic breast cancer treatment and focus on novel drug combination and nanotechnology approaches to overcome the challenges. With improved definition of metastatic tissue target, directed localization and retention of multiple, pharmacologically active drugs to tissues and cells of interest may overcome the limitations in breast cancer treatment that may lead to a cure for breast cancer.

Triple-Negative Breast Cancer: A Brief Review About Epidemiology, Risk Factors, Signaling Pathways, Treatment and Role of Artificial Intelligence

Triple-negative breast cancer (TNBC) is a kind of breast cancer that lacks estrogen, progesterone, and human epidermal growth factor receptor 2. This cancer is responsible for more than 15–20% of all breast cancers and is of particular research interest as it is therapeutically challenging mainly because of its low response to therapeutics and highly invasive nature. The non-availability of specific treatment options for TNBC is usually managed by conventional therapy, which often leads to relapse. The focus of this review is to provide up-to-date information related to TNBC epidemiology, risk factors, metastasis, different signaling pathways, and the pathways that can be blocked, immune suppressive cells of the TNBC microenvironment, current and investigation therapies, prognosis, and the role of artificial intelligence in TNBC diagnosis. The data presented in this paper may be helpful for researchers working in the field to obtain general and particular information to advance the understanding of TNBC and provide suitable disease management in the future.

Resistance to Intervention: Paclitaxel in Breast Cancer

Breast cancer stands as the most prevalent cancer in women globally, and contributes to the highest percentage of mortality due to cancer-related deaths in women. Paclitaxel (PTX) is heavily relied on as a frontline chemotherapy drug in breast cancer treatment, especially in advanced metastatic cancer. Generation of resistance to PTX often derails clinical management and adversely affects patient outcomes. Understanding the molecular mechanism of PTX resistance is necessary to device methods to aid in overcoming the resistance. Recent studies exploring the mechanism of development of PTX resistance have led to unveiling of a range novel therapeutic targets. PTX resistance pathways that involve major regulatory proteins/RNAs like RNF8/Twist/ROR1, TLR, ErbB3/ErbB2, BRCA1- IRIS, MENA, LIN9, MiRNA, FoxM1 and IRAK1 have expanded the complexity of resistance mechanisms, and brought newer insights into the development of drug targets. These resistance-related targets can be dealt with synthetic/natural therapeutics in combination with PTX. The present review encompasses the recent understanding of PTX resistance mechanisms in breast cancer and possible therapeutic combinations to overcome resistance.

Vitamin D3/phospholipid complex decorated caseinate nanomicelles for targeted delivery of synergistic combination therapy in breast cancer

Targeted delivery of cytotoxic drugs has shown great potential in cancer therapy. In this light, vitamin D3 (vit.D3)-coated micelles were fabricated to encapsulate the cytotoxic drug; etoposide (ETP). Sodium caseinate micelles were first utilized to encapsulate vit.D3 and ETP within their hydrophobic core, then drug-loaded micelles were further decorated with an envelope of vit.D3/ phospholipid complex to enhance the active targeting potency of fabricated micelles via exploiting vit.D3 receptors (VDRs) overexpressed on the outer surface of breast cancer cells. In vitro cytotoxicity studies showed that fabricated micelles exhibited improved anticancer effect on MDA MB-231 and MCF-7 human breast cancer cell lines in comparison to free vit.D3 + ETP without any significant toxicity on normal human lung fibroblast (Wi-38) cells. In vivo biodistribution and efficacy studies in Ehrlich ascites tumor animal model revealed that fabricated micelles manifested improved accumulation in tumor tissue due to active targeting potential of vit.D3 without any remarkable toxicity. More importantly, fabricated micelles resulted in enhanced tumor apoptosis, reduced angiogenesis, invasion and autophagy, besides a decline in the tumor expression levels of both miR-21 and miR-192. Therefore, vit.D3/ETP micelles could serve as a favorable actively targeted anticancer delivery system having a superior effect over the free combination.

A Review on Lactoferrin and Central Nervous System Diseases

Central nervous system (CNS) diseases are currently one of the major health issues around the world. Most CNS disorders are characterized by high oxidative stress levels and intense inflammatory responses in affected tissues. Lactoferrin (Lf), a multifunctional iron-binding glycoprotein, plays a significant role in anti-inflammatory, antibacterial, antiviral, reactive oxygen species (ROS) modulator, antitumor immunity, and anti-apoptotic processes. Previous studies have shown that Lf is abnormally expressed in a variety of neurological diseases, especially neurodegenerative diseases. Recently, the promotion of neurodevelopment and neuroprotection by Lf has attracted widespread attention, and Lf could be exploited both as an active therapeutic agent and drug nanocarrier. However, our understanding of the roles of Lf proteins in the initiation or progression of CNS diseases is limited, especially the roles of Lf in regulating neurogenesis. This review highlights recent advances in the understanding of the major pharmacological effects of Lf in CNS diseases, including neurodegenerative diseases, cerebrovascular disease, developmental delays in children, and brain tumors.

Preclinical autophagy modulatory nanomedicines: big challenges, slow advances

INTRODUCTION

Autophagy is a critical housekeeping pathway to remove toxic protein aggregates, damaged organelles, providing cells with bioenergetic substrates needed to survive under adverse conditions. Since altered autophagy is associated with diverse diseases, its pharmacological modulation is considered of therapeutic interest. Nanomedicines may reduce the toxicity and improve the activity of toxic autophagy modulatory drugs (amd).

AREAS COVERED

The status of the most relevant anti-tumor, anti-inflammatory, and anti-infectious treatments mediated by autophagy modulatory nanomedicines (amN) published in the last 5 years is discussed.

EXPERT OPINION

Antitumor and anti-inflammatory treatments may be improved by administering amN for selective, massive, and targeted delivery of amd to diseased tissues. The use of amN as antimicrobial agent remains almost underexploited. Assessing the effect of amN on the complex autophagy machinery operating under different basal diseases, however, is not a trivial task. Besides structural reproducibility, nanomedicines must grant higher efficiency, and lower adverse effects than conventional medication. Simplicity of design, carefully chosen (scalable) preparation techniques, and rigorous monitoring of preclinical efficacy and nanotoxicity will improve the chances of clinical success. Currently, available data are not sufficient to envisage a fast-succeeding translation. Application of quality by design criteria would help to reach such milestones.

Nanotechnology to the Rescue: Treatment Perspective for the Immune Dysregulation Observed in COVID-19

The study of the use of nanotechnology for drug delivery has been extensive. Nanomedical approaches for therapeutics; drug delivery in particular is superior to conventional methods in that it allows for controlled targeted delivery and release, higher stability, extended circulation time, minimal side-effects, and improved pharmacokinetic clearance (of the drug) form the body, to name a few. The magnitude of COVID-19, the current ongoing pandemic has been severe; it has caused widespread the loss of human life. In individuals with severe COVID-19, immune dysregulation and a rampant state of hyperinflammation is observed. This kind of an immunopathological response is detrimental and results in rapid disease progression, development of secondary infections, sepsis and can be fatal. Several studies have pin-pointed the reason for this immune dysregulation; deviations in the signaling pathways involved in the mediation and control of immune responses. In severe COVID-19 patients, many signaling cascades including JAK/STAT, NF-κB, MAPK/ERK, TGF beta, VEGF, and Notch signaling were found to be either upregulated or inactivated. Targeting these aberrant signaling pathways in conjunction with antiviral therapy will effectuate mitigation of the hyperinflammation, hypercytokinemia, and promote faster recovery. The science of the use of nanocarriers as delivery agents to modulate these signaling pathways is not new; it has already been explored for other inflammatory diseases and in particular, cancer therapy. Numerous studies have evaluated the efficacy and potential of nanomedical approaches to modulate these signaling pathways and have been met with positive results. A treatment regime, that includes nanotherapeutics and antiviral therapies will prove effective and holds great promise for the successful treatment of COVID-19. In this article, we review different nanomedical approaches already studied for targeting aberrant signaling pathways, the host immune response to SARS-CoV-2, immunopathology and the dysregulated signaling pathways observed in severe COVID-19 and the current treatment methods in use for targeting signaling cascades in COVID-19. We then conclude by suggesting that the use of nanomedical drug delivery systems for targeting signaling pathways can be extended to effectively target the aberrant signaling pathways in COVID-19 for best treatment results.

Cytotoxic effect of targeted biodegradable epothilone B and rapamycin co-loaded nanocarriers on breast cancer cells

The new therapeutic solutions for breast cancer treatment are needed, for example, combined therapy consisted of several drugs that characterize different mechanisms of action and modern drug delivery systems. Therefore, we used combination of epothilone B (EpoB) and rapamycin (Rap) to analyze the cytotoxic effect against breast cancer cells (MCF-7; MDA-MB-231). Also, the effect of drugs co-delivered in bioresorbable micelles functionalized with biotin (PLA-PEG-BIO; poly(lactide)-co-poly(ethylene glycol)-biotin) was studied. The comparison of effects of the mixture of free drugs and the micelles co-loaded with EpoB and Rap revealed a significant decrease in the cell metabolic activity and survival. Moreover, the dual drug-loaded PLA-PEG-BIO micelles enhanced the cytotoxicity of EpoB and Rap against the tested cells as compared with the free drugs. The blank PLA-PEG-BIO micelles did not affect the tested cells. We expect that mixture of EpoB and Rap may be promising in breast cancer treatment and PLA-PEG-BIO micelles as carrier of these two drugs can be applicable for successful targeted delivery.

Lactoferrin, a unique molecule with diverse therapeutical and nanotechnological applications

Lactoferrin (LF) is a naturally glycoprotein with iron-binding properties and diverse biological applications including; antiviral, anti-inflammatory, antioxidant, anti-cancer and immune stimulating effects. In addition, LF was found to be an ideal nanocarrier for some hydrophobic therapeutics because of its active targeting potential due to overexpression of its receptor on the surface of many cells. Moreover, it was proven to be a good candidate for fabrication of nanocarriers to specifically deliver drugs in case of brain tumors owing to the capability of LF to cross the blood brain barrier (BBB). Consequently, it seems to be a promising molecule with multiple applications in the field of cancer therapy and nanomedicine.

Paclitaxel-Loaded Colloidal Silica and TPGS-Based Solid Self-Emulsifying System Interferes Akt/mTOR Pathway in MDA-MB-231 and Demonstrates Anti-tumor Effect in Syngeneic Mammary Tumors

A solid self-emulsifying drug delivery system (SEDDS) of paclitaxel (PTX) was developed that could enhance its oral bioavailability and neutralize other niggles associated with conventional delivery systems of PTX. TPGS-centered SEDDS containing PTX was optimized by Box-Behnken experimental design and then formulated as fumed colloidal silica-based solid SEDDS microparticles (Si-PTX-S-SEDDS). AFM analysis exhibited round-shaped microparticles of approximately 2-3 μM diameter, whereas after reconstitution, particle size measurement showed nanoemulsion droplets of 30.00 ± 2.00 nm with a zeta potential of 17.38 ± 2.88 mV. Si-PTX-S-SEDDS displayed improved efficacy proven by reduced IC₅₀ of 0.19 ± 0.03 μM against MDA-MB-231 cells and a 45.83-fold higher cellular uptake in comparison to free PTX. Molecular mechanistic studies showed mitochondria-mediated intrinsic pathway of apoptosis following Akt/mTOR pathway, which is accompanied by survivin downregulation. Rhodamine 123 assay and chylomicron flow blocking studies revealed P-gp inhibition potential and lymphatic uptake of Si-PTX-S-SEDDS, responsible for over 4-fold increment in oral bioavailability compared to PTX administered as Taxol. In vivo anti-tumor studies in syngeneic mammary tumor model in SD rats revealed higher efficacy of Si-PTX-S-SEDDS as evident from significant reduction in tumor burden. In total, the developed Si-PTX-S-SEDDS formulation was found as an appropriate option for oral delivery of PTX.

Dendrimer-Mediated Targeted Delivery of Rapamycin to Tumor-Associated Macrophages Improves Systemic Treatment of Glioblastoma

Glioblastoma exhibits high mortality rates due to challenges with drug delivery to the brain and into solid tumors. This two-pronged barrier necessitates high doses of systemic therapies, resulting in significant off-target toxicities. Recently, dendrimer-nanomedicines (without ligands) have shown promise for targeting specific cells in brain tumors from systemic circulation, for improved efficacy and amelioration of systemic toxicities. A dendrimer-rapamycin conjugate (D-Rapa) is presented here that specifically targets tumor-associated macrophages (TAMs) in glioblastoma from systemic administration. D-Rapa improves suppression of pro-tumor expression in activated TAMs and antiproliferative properties of rapamycin in glioma cells in vitro. In vivo, D-Rapa localizes specifically within TAMs, acting as depots to release rapamycin into the tumor microenvironment. This targeted delivery strategy yields improved reduction in tumor burden and systemic toxicities in a challenging, clinically relevant orthotopic syngeneic model of glioblastoma, demonstrating the significant potential of dendrimers as targeted immunotherapies for improving glioblastoma treatment, still an unmet need.

Preparation and characterization of parthenolide nanocrystals for enhancing therapeutic effects of sorafenib against advanced hepatocellular carcinoma

A novel nanocrystals delivery system of parthenolide (PTL) was designed to combined application with sorafenib (Sora) for advanced hepatocellular carcinoma (HCC) therapy, attempting to not only improve the poor aqueous solubility of PTL, but also enhance the synergistic therapeutic effects with Sora. The PTL nanocrystals (PTL-NCs) were prepared by precipitation-high-pressure homogenization method. The formed PTL-NCs with rod morphology possessed size of 126.9 ± 2.31 nm, zeta potential of -11.18 ± 0.59 mV and drug loading of 31.11 ± 1.99%. Meanwhile, PTL in PTL-NCs exhibited excellent storage stability and sustained release behavior. The combination therapy of Sora and PTL-NCs (Sora/PTL-NCs) in vitro for HepG2 cells presented superior therapeutic effects over that of individual PTL and Sora on intracellular uptake, cell proliferation inhibition and migration inhibition. Meanwhile the strongest anti-tumor effect with 81.86% inhibition rate and minimized systemic toxicity of Sora/PTL-NCs in vivo were obtained on tumor-bearing mice compared with that of PTL (48.84%) and Sora (58.83%). Thus, these findings suggested that PTL-NCs as an effective delivery system for the synergistically used with Sora to gain an optimal response against HCC, for referenced in the industrialization of nanocrystals products for intravenous administration.

Synergistic drug combinations for a precision medicine approach to interstitial glioblastoma therapy

Glioblastoma (GBM) is a highly aggressive and heterogeneous form of brain cancer. Genotypic and phenotypic heterogeneity drives drug resistance and tumor recurrence. Combination chemotherapy could overcome drug resistance; however, GBM's location behind the blood-brain barrier severely limits chemotherapeutic options. Interstitial therapy, delivery of chemotherapy locally to the tumor site, via a biodegradable polymer implant can overcome the blood-brain barrier and increase the range of drugs available for therapy. Ideal drug candidates for interstitial therapy are those that are potent against GBM and work in combination with both standard-of-care therapy and new precision medicine targets. Herein we evaluated paclitaxel for interstitial therapy, investigating the effect of combination with both temozolomide, a clinical standard-of-care chemotherapy for GBM, and everolimus, a mammalian target of rapamycin (mTOR) inhibitor that modulates aberrant signaling present in >80% of GBM patients. Tested against a panel of GBM cell lines in vitro, paclitaxel was found to be effective at nanomolar concentrations, complement therapy with temozolomide, and synergize strongly with everolimus. The strong synergism seen with paclitaxel and everolimus was then explored in vivo. Paclitaxel and everolimus were separately formulated into fibrous scaffolds composed of acetalated dextran, a biodegradable polymer with tunable degradation rates, for implantation in the brain. Acetalated dextran degradation rates were tailored to attain matching release kinetics (~3% per day) of both paclitaxel and everolimus to maintain a fixed combination ratio of the two drugs. Combination interstitial therapy of both paclitaxel and everolimus significantly reduced GBM growth and improved progression free survival in two clinically relevant orthotopic models of GBM resection and recurrence. This work illustrates the advantages of synchronized interstitial therapy of paclitaxel and everolimus for post-surgical tumor control of GBM.

Triple-Negative Breast Cancer: A Review of Conventional and Advanced Therapeutic Strategies

Triple-negative breast cancer (TNBC) cells are deficient in estrogen, progesterone and ERBB2 receptor expression, presenting a particularly challenging therapeutic target due to their highly invasive nature and relatively low response to therapeutics. There is an absence of specific treatment strategies for this tumor subgroup, and hence TNBC is managed with conventional therapeutics, often leading to systemic relapse. In terms of histology and transcription profile these cancers have similarities to BRCA-1-linked breast cancers, and it is hypothesized that BRCA1 pathway is non-functional in this type of breast cancer. In this review article, we discuss the different receptors expressed by TNBC as well as the diversity of different signaling pathways targeted by TNBC therapeutics, for example, Notch, Hedgehog, Wnt/b-Catenin as well as TGF-beta signaling pathways. Additionally, many epidermal growth factor receptor (EGFR), poly (ADP-ribose) polymerase (PARP) and mammalian target of rapamycin (mTOR) inhibitors effectively inhibit the TNBCs, but they face challenges of either resistance to drugs or relapse. The resistance of TNBC to conventional therapeutic agents has helped in the advancement of advanced TNBC therapeutic approaches including hyperthermia, photodynamic therapy, as well as nanomedicine-based targeted therapeutics of drugs, miRNA, siRNA, and aptamers, which will also be discussed. Artificial intelligence is another tool that is presented to enhance the diagnosis of TNBC.

BEZ235 enhances chemosensitivity of paclitaxel in hepatocellular carcinoma through inhibiting the PI3K/Akt/mTOR pathway

Desensitization of hepatocellular carcinoma (HCC) to paclitaxel chemotherapy is a major deterrent to successful treatment of the cancer. Abnormal activation of the PI3K/Akt/mTOR, pathway is a common outcome of chemotherapy for HCC. Therefore, we investigated whether BEZ235, a dual PI3K and mTOR inhibitor, could increase the sensitivity of HCC to paclitaxel. In vitro results showed that paclitaxel, combined with BEZ235, inhibited HCC cell proliferation and migration, arrested the cell cycle in the G₂/M phase, and promoted cell apoptosis by decreasing PI3K/Akt/mTOR activity. In vivo experiments confirmed that BEZ235 enhances the anti-tumor effect of paclitaxel by reducing PI3K/Akt/mTOR activity. Immunohistochemical staining showed that paclitaxel combined with BEZ235 reduced the numbers of Ki-67- and GPC3-positive HepG2 cells in tumor tissues. We conclude that BEZ235 enhanced the sensitivity of HCC to paclitaxel, and inhibition of PI3K/Akt/mTOR signaling might be a therapeutic strategy against paclitaxel-resistant HCC.

A tissue chamber chip for assessing nanoparticle mobility in the extravascular space

Although a plethora of nanoparticle configurations have been proposed over the past 10 years, the uniform and deep penetration of systemically injected nanomedicines into the diseased tissue stays as a major biological barrier. Here, a 'Tissue Chamber' chip is designed and fabricated to study the extravascular transport of small molecules and nanoparticles. The chamber comprises a collagen slab, deposited within a PDMS mold, and an 800 μm channel for the injection of the working solution. Through fluorescent microscopy, the dynamics of molecules and nanoparticles was estimated within the gel, under different operating conditions. Diffusion coefficients were derived from the analysis of the particle mean square displacements (MSD). For validating the experimental apparatus and the protocol for data analysis, the diffusion D of FITC-Dextran molecules of 4, 40 and 250 kDa was first quantified. As expected, D reduces with the molecular weight of the dextran molecules. The MSD-derived diffusion coefficients were in good agreement with values derived via fluorescence recovery after photobleaching (FRAP), an alternative technique that solely applies to small molecules. Then, the transport of six nanoparticles with similar hydrodynamic diameters (~ 200 nm) and different surface chemistries was quantified. Surface PEGylation was confirmed to favor the diffusion of nanoparticles within the collagen slab, whereas the surface decoration with hyaluronic acid (HA) chains reduced nanoparticle mobility in a way proportional to the HA molecular weight. To assess further the generality of the proposed approach, the diffusion of the six nanoparticles was also tested in freshly excised brain tissue slices. In these ex vivo experiments, the diffusion coefficients were 5-orders of magnitude smaller than for the Tissue Chamber chip. This was mostly ascribed to the lack of a cellular component in the chip. However, the trends documented for PEGylated and HA-coated nanoparticles in vitro were also confirmed ex vivo. This work demonstrates that the Tissue Chamber chip can be employed to effectively and efficiently test the extravascular transport of nanomedicines while minimizing the use of animals.

Clinical Cancer Nanomedicine

Nanotechnology offers new solutions for the development of cancer therapeutics that display improved efficacy and safety. Although several nanotherapeutics have received clinical approval, the most promising nanotechnology applications for patients still lie ahead. Nanoparticles display unique transport, biological, optical, magnetic, electronic, and thermal properties that are not apparent on the molecular or macroscale, and can be utilized for therapeutic purposes. These characteristics arise because nanoparticles are in the same size range as the wavelength of light and display large surface area to volume ratios. The large size of nanoparticles compared to conventional chemotherapeutic agents or biological macromolecule drugs also enables incorporation of several supportive components in addition to active pharmaceutical ingredients. These components can facilitate solubilization, protection from degradation, sustained release, immunoevasion, tissue penetration, imaging, targeting, and triggered activation. Nanoparticles are also processed differently in the body compared to conventional drugs. Specifically, nanoparticles display unique hemodynamic properties and biodistribution profiles. Notably, the interactions that occur at the bio-nano interface can be exploited for improved drug delivery. This review discusses successful clinically approved cancer nanodrugs as well as promising candidates in the pipeline. These nanotherapeutics are categorized according to whether they predominantly exploit multifunctionality, unique electromagnetic properties, or distinct transport characteristics in the body. Moreover, future directions in nanomedicine such as companion diagnostics, strategies for modifying the microenvironment, spatiotemporal nanoparticle transitions, and the use of extracellular vesicles for drug delivery are also explored.

Bag-1 silencing enhanced chemotherapeutic drug-induced apoptosis in MCF-7 breast cancer cells affecting PI3K/Akt/mTOR and MAPK signaling pathways

The multifunctional anti-apoptotic Bag-1 protein has important roles in apoptosis, proteasome-mediated degradation, transcriptional regulation, and intracellular signaling. Bag-1 promotes cell survival and proliferation, and is overexpressed in breast cancer. Therefore, Bag-1-targeted therapy might be a promising strategy to treat breast cancer. However, the effects of Bag-1 silencing in combination with conventional chemotherapeutic drugs on cell viability and major signaling pathways have not yet been fully investigated in breast cancer cells. In this study, we investigated the cytotoxic effects of Bag-1 silencing, alone and in combination with cisplatin or paclitaxel treatment, in MCF-7 breast cancer cells. Bag-1 knockdown by shRNA or siRNA transfection sensitized MCF-7 cells to apoptosis induced by cisplatin or paclitaxel. Combination of Bag-1 silencing and drug treatment more potently downregulated the pro-survival PI3K/Akt/mTOR and p44/42 mitogen activated protein kinase (MAPK) pathways, and more potently upregulated the stress-activated p38 and SAPK/JNK MAPK pathways. Bag-1-silenced drug-treated cells had also highly reduced proliferative capacity, downregulated cyclin-cyclin dependent kinase complexes and upregulated tumor suppressors p21 and Rb. These results overall indicated that Bag-1 silencing enhanced cisplatin- or paclitaxel-induced cytotoxicity through multiple pathways. In conclusion, Bag-1 targeted therapy might enhance the therapeutic potential of conventional anti-cancer drugs in the treatment of breast cancer.

3D Printing of Poloxamer 407 Nanogel Discs and Their Applications in Adjuvant Ovarian Cancer Therapy

Nanogels are attractive biocompatible materials that enable local delivery of multiple drugs. In this study, we demonstrated that 3D printing technology could be used to precisely construct nanogel discs carrying paclitaxel and rapamycin. 3D-printed nanogel disc rounds (12 mm diameter × 1 mm thickness) carrying paclitaxel and rapamycin evaded premature gelation during storage and the initial burst release of the drugs in the dissolution medium. In vivo 3D-printed nanogel discs permitted successful intraperitoneal delivery of paclitaxel and rapamycin in ES-2-luc ovarian-cancer-bearing xenograft mice. They were also shown to be therapeutically effective and capable of preventing postsurgical peritoneal adhesions in the treated xenograft mice.

Alternating block copolymer-based nanoparticles as tools to modulate the loading of multiple chemotherapeutics and imaging probes

Cancer therapy often relies on the combined action of different molecules to overcome drug resistance and enhance patient outcome. Combined strategies relying on molecules with different pharmacokinetics often fail due to the lack of concomitant tumor accumulation and, thus, to the loss of synergistic effect. Due to their ability to enhance treatment efficiency, improve drug pharmacokinetics, and reduce adverse effects, polymer nanoparticles (PNPs) have been widely investigated as co-delivery vehicles for cancer therapies. However, co-encapsulation of different drugs and probes in PNPs requires a flexible polymer platform and a tailored particle design, in which both the bulk and surface properties of the carriers are carefully controlled. In this work, we propose a core-shell PNP design based on a polyurethane (PUR) core and a phospholipid external surface. The modulation of the hydrophilic/hydrophobic balance of the PUR core enhanced the encapsulation of two chemotherapeutics with dramatically different water solubility (Doxorubicin hydrochloride, DOXO and Docetaxel, DCTXL) and of Iron Oxide Nanoparticles for MRI imaging. The outer shell remained unchanged among the platforms, resulting in un-modified cellular uptake and in vivo biodistribution. We demonstrate that the choice of PUR core allowed a high entrapment efficiency of all drugs, superior or comparable to previously reported results, and that higher core hydrophilicity enhances the loading efficiency of the hydrophilic DOXO and the MRI contrast effect. Moreover, we show that changing the PUR core did not alter the surface properties of the carriers, since all particles showed a similar behavior in terms of cell internalization and in vivo biodistribution. We also show that PUR PNPs have high passive tumor accumulation and that they can efficient co-deliver the two drugs to the tumor, reaching an 11-fold higher DOXO/DCTXL ratio in tumor as compared to free drugs. STATEMENT OF SIGNIFICANCE: Exploiting the synergistic action of multiple chemotherapeutics is a promising strategy to improve the outcome of cancer patients, as different agents can simultaneously engage different features of tumor cells and/or their microenvironment. Unfortunately, the choice is limited to drugs with similar pharmacokinetics that can concomitantly accumulate in tumors. To expand the spectrum of agents that can be delivered in combination, we propose a multi-compartmental core-shell nanoparticles approach, in which the core is made of biomaterials with high affinity for drugs of different physical properties. We successfully co-encapsulated Doxorubicin Hydrochloride, Docetaxel, and contrast agents and achieved a significantly higher concomitant accumulation in tumor versus free drugs, demonstrating that nanoparticles can improve synergistic cancer chemotherapy.

Nanotherapeutics for Treatment of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a devastating and fatal chronic lung disease. While current pharmacotherapies have improved patient quality of life, PAH drugs suffer from limitations in the form of short-term pharmacokinetics, instability, and poor organ specificity. Traditionally, nanotechnology-based delivery strategies have proven advantageous at increasing both circulation lifetimes of chemotherapeutics and accumulation in tumors due to enhanced permeability through fenestrated vasculature. Importantly, increased nanoparticle (NP) accumulation in diseased tissues has been observed pre-clinically in pathologies characterized by endothelial dysfunction and remodeled vasculature, including myocardial infarction and heart failure. Recently, this phenomenon has also been observed in preclinical models of PAH, leading to the exploration of NP-based drug delivery as a therapeutic modality in PAH. Herein, we discussed the advantages of NPs for efficacious treatment of PAH, including heightened therapeutic delivery to diseased lungs for increased drug bioavailability, as well as highlighted innovative nanotherapeutic approaches for PAH.

A multifunctional lipid nanoparticle for co-delivery of paclitaxel and curcumin for targeted delivery and enhanced cytotoxicity in multidrug resistant breast cancer cells

The objective of the work was to develop a multifunctional nanomedicine based on a folate-conjugated lipid nanoparticles loaded with paclitaxel and curcumin. The novel system combines therapeutic advantageous of efficient targeted delivery via folate and timed-release of curcumin and paclitaxel via 2-hydroxypropyl-ß-cyclodextrin, thereby overcoming multidrug resistance in breast cancer cells (MCF-7/ADR). The faster release of curcumin from the folate-conjugated curcumin and paclitaxel-loaded lipid nanoparticles enables sufficient p-glycoprotein inhibition, which allows increased cellular uptake and cytotoxicity of paclitaxel. In western blot assay, curcumin can efficiently inhibit the expression of p-glycoprotein, conformed the enhancement of cytotoxicity by paclitaxel. Furthermore, folate-conjugated curcumin and paclitaxel-loaded lipid nanoparticles exhibited increased uptake of paclitaxel and curcumin into MCF-7/ADR cells through the folate receptor-mediated internalization. Taken together, these results indicate that folate-conjugated curcumin and paclitaxel-loaded lipid nanoparticles enables the enhanced, folate-targeted delivery of multiple anticancer drugs by inhibiting the multi-drug resistance efficiently, which may also serve as a useful nano-system for co-delivery of other anticancer drugs.

Translation of combination nanodrugs into nanomedicines: lessons learned and future outlook

The concept of nanomedicine is not new. For instance, some nanocrystals and colloidal drug molecules are marketed that improve pharmacokinetic characteristics of single-agent therapeutics. For the past two decades, the number of research publications on single-agent nanoformulations has grown exponentially. However, formulations advancing to pre-clinical and clinical evaluations that lead to therapeutic products has been limited. Chronic diseases such as cancer and HIV/AIDS require drug combinations, not single agents, for durable therapeutic responses. Therefore, development and clinical translation of drug combination nanoformulations could play a significant role in improving human health. Successful translation of promising concepts into pre-clinical and clinical studies requires early considerations of the physical compatibility, pharmacological synergy, as well as pharmaceutical characteristics (e.g. stability, scalability and pharmacokinetics). With this approach and robust manufacturing processes in place, some drug-combination nanoparticles have progressed to non-human primate and human studies. In this article, we discuss the rationale and role of drug-combination nanoparticles, the pre-clinical and clinical research progress made to date and the key challenges for successful clinical translation. Finally, we offer insight to accelerate clinical translation through leveraging robust nanoplatform technologies to enable implementation of personalised and precision medicine.

Rapamycin nanoparticles localize in diseased lung vasculature and prevent pulmonary arterial hypertension

Vascular remodeling resulting from pulmonary arterial hypertension (PAH) leads to endothelial fenestrations. This feature can be exploited by nanoparticles (NP), allowing them to extravasate from circulation and accumulate in remodeled pulmonary vessels. Hyperactivation of the mTOR pathway in PAH drives pulmonary arterial smooth muscle cell proliferation. We hypothesized that rapamycin (RAP)-loaded NPs, an mTOR inhibitor, would accumulate in diseased lungs, selectively targeting vascular mTOR and preventing PAH progression. RAP poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-PCL) NPs were fabricated. NP accumulation and efficacy were examined in a rat monocrotaline model of PAH. Following intravenous (IV) administration, NP accumulation in diseased lungs was verified via LC/MS analysis and confocal imaging. Pulmonary arteriole thickness, right ventricular systolic pressures, and ventricular remodeling were determined to assess the therapeutic potential of RAP NPs. Monocrotaline-exposed rats showed increased NP accumulation within lungs compared to healthy controls, with NPs present to a high extent within pulmonary perivascular regions. RAP, in both free and NP form, attenuated PAH development, with histological analysis revealing minimal changes in pulmonary arteriole thickness and no ventricular remodeling. Importantly, NP-treated rats showed reduced systemic side effects compared to free RAP. This study demonstrates the potential for nanoparticles to significantly impact PAH through site-specific delivery of therapeutics.

Rapamycin-loaded Immunoliposomes Functionalized with Trastuzumab: A Strategy to Enhance Cytotoxicity to HER2-positive Breast Cancer Cells

BACKGROUND

Liposomes have been employed to improve pharmacokinetics and reduce side effects of drugs. They can be functionalized with antibodies for targeted delivery. While the monoclonal antibody trastuzumab has been employed in the therapy of HER2-positive breast cancer, the resistance developed during treatment has been reported. Rapamycin could be used in combination with trastuzumab for improved therapeutic response.

OBJECTIVE

In this study, we aimed to develop rapamycin-loaded liposomes and immunoliposomes with trastuzumab, characterize them and evaluate their in vitro cytotoxicity.

METHOD

Formulations were prepared by the thin film hydration method and immunoliposome was conjugated to antibody by covalent bond. Characterization involved particle size, polydispersity, zeta potential, encapsulation efficiency, functionalization efficiency, DSC and FTIR assays. Cell studies were conducted through the MTT assay.

RESULTS

SPC:Chol:DSPE-PEG formulation prepared at 1:10 drug to lipid ratio presented high encapsulation efficiency, appropriate particle size, low polydispersity, negative zeta potential and colloidal stability. Rapamycin exhibited intermolecular interactions with lipids and underwent crystallinity reduction. Rapamycin-loaded immunoliposomes were prepared with high trastuzumab functionalization efficiency and antibody stability. Cytotoxicity studies showed that the HER2-positive SK-BR-3 cell line was sensitive to trastuzumab, either as free drug or in the context of immunoliposomes, and is more sensitive to rapamycin than the triple negative MDA-MB-231 cells. For MDA-MB-231, the liposomal rapamycin was more cytotoxic than the free drug. Furthermore, the immunoliposomes showed potent cytotoxicity against SK-BR-3 cells. Finally, rapamycin and trastuzumab exhibited in vitro synergistic effect, particularly through immunoliposomes.

CONCLUSION

The formulation developed herein has potential for in vivo evaluation.

Biomaterials to suppress cancer stem cells and disrupt their tumoral niche

Lack of improvement in the treatment options of several types of cancer can largely be attributed to the presence of a subpopulation of cancer cells with stem cell signatures and to the tumoral niche that supports and protects these cells. This review analyses the main strategies that specifically modulate or suppress cancer stem cells (CSCs) and the tumoral niche (TN), focusing on the role of biomaterials (i.e. implants, nanomedicines, etc.) in these therapies. In the case of CSCs, we discuss differentiation therapies and the disruption of critical cellular signaling networks. For the TN, we analyze diverse strategies to modulate tumor hypervascularization and hypoxia, tumor extracellular matrix, and the inflammatory and tumor immunosuppressive environment. Due to their capacity to control drug disposition and integrate diverse functionalities, biomaterial-based therapies can provide important benefits in these strategies. We illustrate this by providing case studies where biomaterial-based therapies either show CSC suppression and TN disruption or improved delivery of major modulators of these features. Finally, we discuss the future of these technologies in the framework of these emerging therapeutic concepts.

Nanomedicine of synergistic drug combinations for cancer therapy - Strategies and perspectives

Nanomedicine of synergistic drug combinations has shown increasing significance in cancer therapy due to its promise in providing superior therapeutic benefits to the current drug combination therapy used in clinical practice. In this article, we will examine the rationale, principles, and advantages of applying nanocarriers to improve anticancer drug combination therapy, review the use of nanocarriers for delivery of a variety of combinations of different classes of anticancer agents including small molecule drugs and biologics, and discuss the challenges and future perspectives of the nanocarrier-based combination therapy. The goal of this review is to provide better understanding of this increasingly important new paradigm of cancer treatment and key considerations for rational design of nanomedicine of synergistic drug combinations for cancer therapy.

Efficient antitumor effect of co-drug-loaded nanoparticles with gelatin hydrogel by local implantation

Tetrandrine (Tet) could enhance the antitumor effect of Paclitaxel (Ptx) by increasing intracellular Reactive Oxygen Species (ROS) levels, which leads to the possibility of co-delivery of both drugs for synergistic antitumor effect. In the current study, we reported an efficient, local therapeutic strategy employing effective Tet and Ptx delivery with a nanoparticle-loaded gelatin system. Tet- and Ptx co-loaded mPEG-PCL nanoparticles (P/T-NPs) were encapsulated into the physically cross-linked gelatin hydrogel and then implanted on the tumor site for continuous drug release. The drug-loaded gelatin hydrogel underwent a phase change when the temperature slowly increased. In vitro study showed that Tet/Ptx-loaded PEG-b-PCL nanoparticles encapsulated within a gelatin hydrogel (P/T-NPs-Gelatin) inhibited the growth and invasive ability of BGC-823 cells more effectively than the combination of free drugs or P/T-NPs. In vivo study validated the therapeutic potential of P/T-NPs-Gelatin. P/T-NPs-Gelatin significantly inhibited the activation of p-Akt and the downstream anti-apoptotic Bcl-2 protein and also inducing the activation of pro-apoptotic Bax protein. Moreover, the molecular-modulating effect of P/T-NPs-Gelatin on related proteins varied slightly under the influence of NAC, which was supported by the observations of the tumor volumes and weights. Based on these findings, local implantation of P/T-NPs-Gelatin may be a promising therapeutic strategy for the treatment of gastric cancer.

A Micro/Nano Composite for Combination Treatment of Melanoma Lung Metastasis

The successful treatment of malignant disease generally requires the use of multiple therapeutic agents that are coordinated in a spatiotemporal manner to enable synergy. Here, a porous silicon-based micro/nano composite (MNC) that is capable of simultaneously delivering chemotherapeutic agents and small interfering RNA (siRNA) to the lungs following intravenous injection is designed. The pores of the silicon microparticles are loaded with B-Raf proto-oncogene serine/threonine kinase (BRAF) siRNA-containing liposomes, while the surface is conjugated with docetaxel-encapsulated polymeric nanoparticles. The synergistic antitumor effect of the MNC is demonstrated in vitro in melanoma cells and in vivo using a mouse model for melanoma lung metastasis. The MNC displays superior therapeutic efficacy and increased accumulation in metastatic melanoma lesions in the lungs in comparison to combination therapy with liposomes and polymers. The results indicate that the MNC can be used as an effective delivery vehicle for simultaneous enrichment of multiple therapeutic agents in the lungs.

Cancer stem cells and personalized cancer nanomedicine

Despite the progress in cancer treatment over the past years advanced cancer is still an incurable disease. Special attention is pointed toward cancer stem cell (CSC)-targeted therapies, because this minor cell population is responsible for the treatment resistance, metastatic growth and tumor recurrence. The recently described CSC dynamic phenotype and interconversion model of cancer growth hamper even more the possible success of current cancer treatments in advanced cancer stages. Accordingly, CSCs can be generated through dedifferentiation processes from non-CSCs, in particular, when CSC populations are depleted after treatment. In this context, the use of targeted CSC nanomedicines should be considered as a promising tool to increase CSC sensitivity and efficacy of specific anti-CSC therapies.

Co-loaded paclitaxel/rapamycin liposomes: Development, characterization and in vitro and in vivo evaluation for breast cancer therapy

Paclitaxel and rapamycin have been reported to act synergistically to treat breast cancer. Albeit paclitaxel is available for breast cancer treatment, the most commonly used formulation in the clinic presents side effects, limiting its use. Furthermore, both drugs present pharmacokinetics drawbacks limiting their in vivo efficacy and clinic combination. As an alternative, drug delivery systems, particularly liposomes, emerge as an option for drug combination, able to simultaneously deliver co-loaded drugs with improved therapeutic index. Therefore, the purpose of this study is to develop and characterize a co-loaded paclitaxel and rapamycin liposome and evaluate it for breast cancer efficacy both in vitro and in vivo. Results showed that a SPC/Chol/DSPE-PEG (2000) liposome was able to co-encapsulate paclitaxel and rapamycin with suitable encapsulation efficiency values, nanometric particle size, low polydispersity and neutral zeta potential. Taken together, FTIR and thermal analysis evidenced drug conversion to the more bioavailable molecular and amorphous forms, respectively, for paclitaxel and rapamycin. The pegylated liposome exhibited excellent colloidal stability and was able to retain drugs encapsulated, which were released in a slow and sustained fashion. Liposomes were more cytotoxic to 4T1 breast cancer cell line than the free drugs and drugs acted synergistically, particularly when co-loaded. Finally, in vivo therapeutic evaluation carried out in 4T1-tumor-bearing mice confirmed the in vitro results. The co-loaded paclitaxel/rapamycin pegylated liposome better controlled tumor growth compared to the solution. Therefore, we expect that the formulation developed herein might be a contribution for future studies focusing on the clinical combination of paclitaxel and rapamycin.

Bioinert Anodic Alumina Nanotubes for Targeting of Endoplasmic Reticulum Stress and Autophagic Signaling: A Combinatorial Nanotube-Based Drug Delivery System for Enhancing Cancer Therapy

Although nanoparticle-based targeted delivery systems have gained promising achievements for cancer therapy, the development of sophisticated strategies with effective combinatorial therapies remains an enduring challenge. Herein, we report the fabrication of a novel nanomaterial, so-called anodic alumina nanotubes (AANTs) for proof-of-concept cancer therapy by targeting cell signaling networks. This strategy is to target autophagic and endoplasmic reticulum (ER) stress signaling by using thapsigargin (TG)-loaded AANTs cotreated with an autophagy inhibitor 3-methyladenine (3-MA). We first show that AANTs are nontoxic and can activate autophagy in different cell types including human fibroblast cells (HFF), human monocyte cells (THP-1), and human breast cancer cells (MDA-MB 231-TXSA). Treatment with 3-MA at a nontoxic dose reduced the level of autophagy induced by AANTs, and consequently sensitized breast cancer cells to AANTs-induced cellular stresses. To target autophagic and ER stress signaling networking, breast cancer cells were treated with 3-MA together with AANTs loaded with the prototype ER stress inducer TG. We demonstrated that 3-MA enhanced the cancer cell killing effect of AANTs loaded with TG. This effect was associated with enhanced ER stress signaling due to the combination effect of TG and 3-MA. These findings not only demonstrate the excellent biocompatibility of AANTs as novel biomaterials but also provide new opportunities for developing ER- and autophagy-targeted delivery systems for future clinical cancer therapy.

When 1+1>2: Nanostructured composites for hard tissue engineering applications

Multicomponent, synergistic and multifunctional nanostructures have taken over the spotlight in the realm of biomedical nanotechnologies. The most prospective materials for bone regeneration today are almost exclusively composites comprising two or more components that compensate for the shortcomings of each one of them alone. This is quite natural in view of the fact that all hard tissues in the human body, except perhaps the tooth enamel, are composite nanostructures. This review article highlights some of the most prospective breakthroughs made in this research direction, with the hard tissues in main focus being those comprising bone, tooth cementum, dentin and enamel. The major obstacles to creating collagen/apatite composites modeled after the structure of bone are mentioned, including the immunogenicity of xenogeneic collagen and continuously failing attempts to replicate the biomineralization process in vitro. Composites comprising a polymeric component and calcium phosphate are discussed in light of their ability to emulate the soft/hard composite structure of bone. Hard tissue engineering composites created using hard material components other than calcium phosphates, including silica, metals and several types of nanotubes, are also discoursed on, alongside additional components deliverable using these materials, such as cells, growth factors, peptides, antibiotics, antiresorptive and anabolic agents, pharmacokinetic conjugates and various cell-specific targeting moieties. It is concluded that a variety of hard tissue structures in the body necessitates a similar variety of biomaterials for their regeneration. The ongoing development of nanocomposites for bone restoration will result in smart, theranostic materials, capable of acting therapeutically in direct feedback with the outcome of in situ disease monitoring at the cellular and subcellular scales. Progress in this research direction is expected to take us to the next generation of biomaterials, designed with the purpose of fulfilling Daedalus' dream - not restoring the tissues, but rather augmenting them.

Nanoparticle-Based ARV Drug Combinations for Synergistic Inhibition of Cell-Free and Cell-Cell HIV Transmission

Nanocarrier-based drug delivery systems are playing an emerging role in human immunodeficiency virus (HIV) chemoprophylaxis and treatment due to their ability to alter the pharmacokinetics and improve the therapeutic index of various antiretroviral (ARV) drug compounds used alone and in combination. Although several nanocarriers have been described for combination delivery of ARV drugs, measurement of drug-drug activities facilitated by the use of these nanotechnology platforms has not been fully investigated for topical prevention. Here, we show that physicochemically diverse ARV drugs can be encapsulated within polymeric nanoparticles to deliver multidrug combinations that provide potent HIV chemoprophylaxis in relevant models of cell-free, cell-cell, and mucosal tissue infection. In contrast to existing approaches that coformulate ARV drug combinations together in a single nanocarrier, we prepared single-drug-loaded nanoparticles that were subsequently combined upon administration. ARV drug-nanoparticles were prepared using emulsion-solvent evaporation techniques to incorporate maraviroc (MVC), etravirine (ETR), and raltegravir (RAL) into poly(lactic-co-glycolic acid) (PLGA) nanoparticles. We compared the antiviral potency of the free and formulated drug combinations for all pairwise and triple drug combinations against both cell-free and cell-associated HIV-1 infection in vitro. The efficacy of ARV-drug nanoparticle combinations was also assessed in a macaque cervicovaginal explant model using a chimeric simian-human immunodeficiency virus (SHIV) containing the reverse transcriptase (RT) of HIV-1. We observed that our ARV-NPs maintained potent HIV inhibition and were more effective when used in combinations. In particular, ARV-NP combinations involving ETR-NP exhibited significantly higher antiviral potency and dose-reduction against both cell-free and cell-associated HIV-1 BaL infection in vitro. Furthermore, ARV-NP combinations that showed large dose-reduction were identified to be synergistic, whereas the equivalent free-drug combinations were observed to be strictly additive. Higher intracellular drug concentration was measured for cells dosed with the triple ARV-NP combination compared to the equivalent unformulated drugs. Finally, as a first step toward evaluating challenge studies in animal models, we also show that our ARV-NP combinations inhibit RT-SHIV virus propagation in macaque cervicovaginal tissue and block virus transmission by migratory cells emigrating from the tissue. Our results demonstrate that ARV-NP combinations control HIV-1 transmission more efficiently than free-drug combinations. These studies provide a rationale to better understand the role of nanocarrier systems in facilitating multidrug effects in relevant cells and tissues associated with HIV infection.

Co-Eradication of Breast Cancer Cells and Cancer Stem Cells by Cross-Linked Multilamellar Liposomes Enhances Tumor Treatment

The therapeutic limitations of conventional chemotherapeutic drugs have emerged as a challenge for breast cancer therapy; these shortcomings are likely due, at least in part, to the presence of the cancer stem cells (CSCs). Salinomycin, a polyether antibiotic isolated from Streptomyces albus, has been shown to selectively inhibit cancer stem cells; however, its clinical application has been hindered by the drug's hydrophobility, which limits the available administration routes. In this paper, a novel drug delivery system, cross-linked multilamellar liposomal vesicles (cMLVs), was optimized to allow for the codelivery of salinomycin (Sal) and doxorubicin (Dox), targeting both CSCs and breast cancer cells. The results show that the cMLV particles encapsulating different drugs have similar sizes with high encapsulation efficiencies (>80%) for both Dox and Sal. Dox and Sal were released from the particles in a sustained manner, indicating the stability of the cMLVs. Moreover, the inhibition of cMLV(Dox+Sal) against breast cancer cells was stronger than either single-drug treatment. The efficient targeting of cMLV(Dox+Sal) to CSCs was validated through in vitro experiments using breast cancer stem cell markers. In accordance with the in vitro combination treatment, in vivo breast tumor suppression by cMLV(Dox+Sal) was 2-fold more effective than single-drug cMLV treatment or treatment with the combination of cMLV(Dox) and cMLV(Sal). Thus, this study demonstrates that cMLVs represent a novel drug delivery system that can serve as a potential platform for combination therapy, allowing codelivery of an anticancer agent and a CSC inhibitor for the elimination of both breast cancer cells and cancer stem cells.

Tumor-Targeted Synergistic Blockade of MAPK and PI3K from a Layer-by-Layer Nanoparticle

PURPOSE

Cross-talk and feedback between the RAS/RAF/MEK/ERK and PI3K/AKT/mTOR cell signaling pathways is critical for tumor initiation, maintenance, and adaptive resistance to targeted therapy in a variety of solid tumors. Combined blockade of these pathways-horizontal blockade-is a promising therapeutic strategy; however, compounded dose-limiting toxicity of free small molecule inhibitor combinations is a significant barrier to its clinical application.

EXPERIMENTAL DESIGN

AZD6244 (selumetinib), an allosteric inhibitor of Mek1/2, and PX-866, a covalent inhibitor of PI3K, were co-encapsulated in a tumor-targeting nanoscale drug formulation-layer-by-layer (LbL) nanoparticles. Structure, size, and surface charge of the nanoscale formulations were characterized, in addition to in vitro cell entry, synergistic cell killing, and combined signal blockade. In vivo tumor targeting and therapy was investigated in breast tumor xenograft-bearing NCR nude mice by live animal fluorescence/bioluminescence imaging, Western blotting, serum cytokine analysis, and immunohistochemistry.

RESULTS

Combined MAPK and PI3K axis blockade from the nanoscale formulations (160 ± 20 nm, -40 ± 1 mV) was synergistically toxic toward triple-negative breast (MDA-MB-231) and RAS-mutant lung tumor cells (KP7B) in vitro, effects that were further enhanced upon encapsulation. In vivo, systemically administered LbL nanoparticles preferentially targeted subcutaneous MDA-MB-231 tumor xenografts, simultaneously blocked tumor-specific phosphorylation of the terminal kinases Erk and Akt, and elicited significant disease stabilization in the absence of dose-limiting hepatotoxic effects observed from the free drug combination. Mice receiving untargeted, but dual drug-loaded nanoparticles exhibited progressive disease.

CONCLUSIONS

Tumor-targeting nanoscale drug formulations could provide a more safe and effective means to synergistically block MAPK and PI3K in the clinic.

An overview of nanotoxicity and nanomedicine research: principles, progress and implications for cancer therapy

The studies of nanomaterial-based drug delivery and nanotoxicity are closely interconnected.