Nuclear Localizing Peptide-Conjugated, Redox-Sensitive Polymersomes for Delivering Curcumin and Doxorubicin to Pancreatic Cancer Microtumors

Nanoassemblies designed for efficient nuclear targeting

One of the key aspects of coping efficiently with complex pathological conditions is delivering the desired therapeutic compounds with precision in both space and time. Therefore, the focus on nuclear-targeted delivery systems has emerged as a promising strategy with high potential, particularly in gene therapy and cancer treatment. Here, we explore the design of supramolecular nanoassemblies as vehicles to deliver specific compounds to the nucleus, with the special focus on polymer and peptide-based carriers that expose nuclear localization signals. Such nanoassemblies aim at maximizing the concentration of genetic and therapeutic agents within the nucleus, thereby optimizing treatment outcomes while minimizing off-target effects. A complex scenario of conditions, including cellular uptake, endosomal escape, and nuclear translocation, requires fine tuning of the nanocarriers' properties. First, we introduce the principles of nuclear import and the role of nuclear pore complexes that reveal strategies for targeting nanosystems to the nucleus. Then, we provide an overview of cargoes that rely on nuclear localization for optimal activity as their integrity and accumulation are crucial parameters to consider when designing a suitable delivery system. Considering that they are in their early stages of research, we present various cargo-loaded peptide- and polymer nanoassemblies that promote nuclear targeting, emphasizing their potential to enhance therapeutic response. Finally, we briefly discuss further advancements for more precise and effective nuclear delivery.

Remotely Controlled Surface Charge Modulation of Magnetoelectric Nanogenerators for Swift and Efficient Drug Delivery

We have developed a highly efficient technique of magnetically controlled swift loading and release of doxorubicin (DOX) drug using a magnetoelectric nanogenerator (MENG). Core-shell nanostructured MENG with a magnetostrictive core and piezoelectric shell act as field-responsive nanocarriers and possess the capability of field-triggered drug release in a cancerous environment. MENGs generate a surface electric dipole when subjected to a magnetic field due to the strain-mediated magnetoelectric effect. The capability of directional magnetic field-assisted modulation of the surface electrical dipole of MENG provides a mechanism to create/break ionic bonds with DOX molecules, which facilitates efficient drug attachment and on-demand swift detachment of the drug at a targeted site. The magnetic field-assisted drug-loading mechanism was minutely analyzed using spectrophotometry and Raman spectroscopy. The detailed time-dependent analysis of controlled drug release by the MENG under unidirectional and rotating magnetic field excitation was conducted using field-emission scanning electron microscopy, energy-dispersive X-ray, and atomic force microscopic measurements. In vitro, experiments validate the cytocompatibility and magnetically assisted on-demand and swift DOX drug delivery by the MENG near MCF-7 breast cancer cells, which results in a significant enhancement of cancer cell killing efficiency. A state-of-the-art experiment was performed to visualize the nanoscale magnetoelectric effect of MENG using off-axis electron holography under Lorentz conditions.

Polymersome Membrane Engineering with Active Targeting or Controlled Permeability for Responsive Drug Delivery

Polymersomes have been extensively investigated for drug delivery as nanocarriers for two decades due to a series of advantages including high stability under physiological conditions, simultaneous encapsulation of hydrophilic and hydrophobic drugs inside inner cavities and membranes, respectively, and facile adjustment of membrane and surface properties, as well as controlled drug release through incorporation of stimuli-responsive components. Despite these features, polymersome nanocarriers frequently suffer from nontargeting delivery and poor membrane permeability. In recent years, polymersomes have been functionalized for more efficient drug delivery. The surface shells were explored to be modified with diverse active targeting groups to improve disease-targeting delivery. The membrane permeability of the polymersomes was adjusted by incorporation of the stimuli-responsive components for smart controlled transportation of the encapsulated drugs. Therefore, being the polymersome-biointerface, tailorable properties can be introduced by its carefully modulated engineering. This review elaborates on the role of polymersome membranes as a platform to incorporate versatile features. First, we discuss how surface functionalization facilitates the directional journey to the targeting sites toward specific diseases, cells, or intracellular organelles via active targeting. Moreover, recent advances in the past decade related to membrane permeability to control drug release are also summarized. We finally discuss future development to promote polymersomes as in vivo drug delivery nanocarriers.

The bioengineered and multifunctional nanoparticles in pancreatic cancer therapy: Bioresponisive nanostructures, phototherapy and targeted drug delivery

The multidisciplinary approaches in treatment of cancer appear to be essential in term of bringing benefits of several disciplines and their coordination in tumor elimination. Because of the biological and malignant features of cancer cells, they have ability of developing resistance to conventional therapies such as chemo- and radio-therapy. Pancreatic cancer (PC) is a malignant disease of gastrointestinal tract in which chemotherapy and radiotherapy are main tools in its treatment, and recently, nanocarriers have been emerged as promising structures in its therapy. The bioresponsive nanocarriers are able to respond to pH and redox, among others, in targeted delivery of cargo for specific treatment of PC. The loading drugs on the nanoparticles that can be synthetic or natural compounds, can help in more reduction in progression of PC through enhancing their intracellular accumulation in cancer cells. The encapsulation of genes in the nanoparticles can protect against degradation and promotes intracellular accumulation in tumor suppression. A new kind of therapy for cancer is phototherapy in which nanoparticles can stimulate both photothermal therapy and photodynamic therapy through hyperthermia and ROS overgeneration to trigger cell death in PC. Therefore, synergistic therapy of phototherapy with chemotherapy is performed in accelerating tumor suppression. One of the important functions of nanotechnology is selective targeting of PC cells in reducing side effects on normal cells. The nanostructures are capable of being surface functionalized with aptamers, proteins and antibodies to specifically target PC cells in suppressing their progression. Therefore, a specific therapy for PC is provided and future implications for diagnosis of PC is suggested.

Superior biocompatible carbon dots for dynamic fluorescence imaging of nucleoli in living cells

The nucleolus is a newly developed and promising target for cancer diagnosis and therapy, and its imaging is extremely significant for fundamental research and clinical applications. The unique feature, i.e., high resolution at the subcellular level, makes the fluorescence imaging method a powerful tool for nucleolus imaging. However, the fluorescence imaging of nucleoli in living cells is restricted by the limited availability of fluorescent agents with specific nucleolus-targeting capability and superior biocompatibility. Here, promising carbon dots (CDs) with intrinsic nucleolus-targeting capability were synthesized, characterized and employed for dynamic fluorescence imaging of nucleoli in living cells. The CDs exhibit a high fluorescence quantum yield of 0.2, excellent specificity and photostability, and superior biocompatibility, which were systematically demonstrated at the gene, cellular and animal levels and confirmed by their biological effects on embryonic development. All these features enabled CDs to light up the nucleoli for a long time with a high signal-to-noise ratio in living cells and monitor the nucleolar dynamics of malignant cells in camptothecin (CPT) based chemotherapy. Their excellent optical and biological features as well as general nucleolus-targeting capability endow CDs with great potential for future translational research.

Design of Nanoparticles in Cancer Therapy Based on Tumor Microenvironment Properties

Cancer is one of the leading causes of death worldwide, and battling cancer has always been a challenging subject in medical sciences. All over the world, scientists from different fields of study try to gain a deeper knowledge about the biology and roots of cancer and, consequently, provide better strategies to fight against it. During the past few decades, nanoparticles (NPs) have attracted much attention for the delivery of therapeutic and diagnostic agents with high efficiency and reduced side effects in cancer treatment. Targeted and stimuli-sensitive nanoparticles have been widely studied for cancer therapy in recent years, and many more studies are ongoing. This review aims to provide a broad view of different nanoparticle systems with characteristics that allow them to target diverse properties of the tumor microenvironment (TME) from nanoparticles that can be activated and release their cargo due to the specific characteristics of the TME (such as low pH, redox, and hypoxia) to nanoparticles that can target different cellular and molecular targets of the present cell and molecules in the TME.

A technical note on emerging combination approach involved in the onconanotherapeutics

Cancer is the second cause of mortality worldwide, and the currently available conventional treatment approach is associated with serious side effects and poor clinical outcomes. Based on the outcome of the exploratory preclinical and clinical studies, it was found that therapeutic response increases multiple folds when anticancer drugs are used in combination. However, the conventional combination of anticancer drugs was associated with various limitations such as increased cost of treatment, systemic toxicity, drug resistance, and reduced pharmacokinetic attributes. Hence, attempts were made to formulate nanocarrier fabricated combinatorial drugs (NFCDs) to effectively manage and treat cancer. This approach offers several advantages, such as improved stability, lower drug exposure, targeted drug delivery, low side effects, and improved clinical outcome. Hence, in this review, first time, we have discussed the recent advancement and various types of nano carrier-based combinatorial drug delivery systems in a different type of cancer and highlighted the personalized combinatorial theranostic medicine as a futuristic anticancer treatment approach.

Redox-Responsive Polymersomes as Smart Doxorubicin Delivery Systems

Stimuli-responsive polymersomes have emerged as smart drug delivery systems for programmed release of highly cytotoxic anticancer agents such as doxorubicin hydrochloride (Dox·HCl). Recently, a biodegradable redox-responsive triblock copolymer (mPEG–PDH–mPEG) was synthesized with a central hydrophobic block containing disulfide linkages and two hydrophilic segments of poly(ethylene glycol) methyl ether. Taking advantage of the self-assembly of this amphiphilic copolymer in aqueous solution, in the present investigation we introduce a solvent-exchange method that simultaneously achieves polymersome formation and drug loading in phosphate buffer saline (10 mM, pH 7.4). Blank and drug-loaded polymersomes (5 and 10 wt.% feeding ratios) were prepared and characterized for morphology, particle size, surface charge, encapsulation efficiency and drug release behavior. Spherical vesicles of uniform size (120–190 nm) and negative zeta potentials were obtained. Dox·HCl was encapsulated into polymersomes with a remarkably high efficiency (up to 98 wt.%). In vitro drug release studies demonstrated a prolonged and diffusion-driven release at physiological conditions (~34% after 48 h). Cleavage of the disulfide bonds in the presence of 50 mM glutathione (GSH) enhanced drug release (~77%) due to the contribution of the erosion mechanism. Therefore, the designed polymersomes are promising candidates for selective drug release in the reductive environment of cancer cells.

Stimuli-Responsive Hybrid Metal Nanocomposite - A Promising Technology for Effective Anticancer Therapy

Cancer is one of the most challenging, life-threatening illnesses to cure, with over 10 million new cases diagnosed each year globally. Improved diagnostic cum treatment with common side-effects are warranting for successful therapy. Nanomaterials are recognized to improve early diagnosis, imaging, and treatment. Recently, multifunctional nanocomposites attracted considerable interest due to their low-cost production, and ideal thermal and chemical stability, and will be beneficial in future diagnostics and customized treatment capacity. Stimuli-Responsive Hybrid Metal Nanocomposites (SRHMNs) based nanocomposite materials pose the on/off delivery of bioactive compounds such as medications, genes, RNA, and DNA to specific tissue or organs and reduce toxicity. They simultaneously serve as sophisticated imaging and diagnostic tools when certain stimuli (e.g., temperature, pH, redox, ultrasound, or enzymes) activate the nanocomposite, resulting in the imaging-guided transport of the payload at defined sites. This review in detail addresses the recent advancements in the design and mechanism of internal breakdown processes of the functional moiety from stimuli-responsive systems in response to a range of stimuli coupled with metal nanoparticles. Also, it provides a thorough understanding of SRHMNs, enabling non-invasive interventional therapy by resolving several difficulties in cancer theranostics.

Design and preparation of a theranostic peptideticle for targeted cancer therapy: Peptide-based codelivery of doxorubicin/curcumin and graphene quantum dots

Although chemotherapy has been known as a powerful medication for cancer treatment over the years, there is an important necessity for designing a novel targeted drug delivery system to overcome the drawbacks of this conventional method including undesired side effects on normal cells and drug resistance. The structural differences between the surface of cancerous and normal cells allow to design and engineer targeted drug delivery systems for cancer treatment. Integrins as one of the cell surface receptors over-expressed in cancer cells could potentially be suitable candidates for targeting cancer cells. In the present study, the novel nano-carriers based on designed MiRGD peptides and graphene quantum dots (GQDs) have been used for targeted delivery of doxorubicin (Dox) and curcumin (Cur) as hydrophilic and hydrophobic drug models, respectively. The prepared nano-composites were characterized by UV-vis and photoluminescence (PL) spectroscopies, Zeta-Sizer and transmission electron microscopy (TEM). Altogether, the results of cellular uptake and fluorimetric assays performed in HUVEC and HFF cells as models of αv integrin-over-expressed cancer and normal cells, respectively, besides in-vivo study on breast cancer bearing BALB/c mice, demonstrated that the prepared nano-composites can be considered as suitable multifunctional theranostic peptideticles for targeted drug delivery and tracking.

Current Perspectives on Synthetic Compartments for Biomedical Applications

Nano- and micrometer-sized compartments composed of synthetic polymers are designed to mimic spatial and temporal divisions found in nature. Self-assembly of polymers into compartments such as polymersomes, giant unilamellar vesicles (GUVs), layer-by-layer (LbL) capsules, capsosomes, or polyion complex vesicles (PICsomes) allows for the separation of defined environments from the exterior. These compartments can be further engineered through the incorporation of (bio)molecules within the lumen or into the membrane, while the membrane can be decorated with functional moieties to produce catalytic compartments with defined structures and functions. Nanometer-sized compartments are used for imaging, theranostic, and therapeutic applications as a more mechanically stable alternative to liposomes, and through the encapsulation of catalytic molecules, i.e., enzymes, catalytic compartments can localize and act in vivo. On the micrometer scale, such biohybrid systems are used to encapsulate model proteins and form multicompartmentalized structures through the combination of multiple compartments, reaching closer to the creation of artificial organelles and cells. Significant progress in therapeutic applications and modeling strategies has been achieved through both the creation of polymers with tailored properties and functionalizations and novel techniques for their assembly.

Design of Smart Size-, Surface-, and Shape-Switching Nanoparticles to Improve Therapeutic Efficacy

Multiple biological barriers must be considered in the design of nanomedicines, including prolonged blood circulation, efficient accumulation at the target site, effective penetration into the target tissue, selective uptake of the nanoparticles into target cells, and successful endosomal escape. However, different particle sizes, surface chemistries, and sometimes shapes are required to achieve the desired transport properties at each step of the delivery process. In response, this review highlights recent developments in the design of switchable nanoparticles whose size, surface chemistry, shape, or a combination thereof can be altered as a function of time, a disease-specific microenvironment, and/or via an externally applied stimulus to enable improved optimization of nanoparticle properties in each step of the delivery process. The practical use of such nanoparticles in chemotherapy, bioimaging, photothermal therapy, and other applications is also discussed.

Doxorubicin nanoformulations on therapy against cancer: An overview from the last 10 years

Doxorubicin (DOX) is a natural antibiotic with antineoplastic activity. It has been used for over 40 years and remains one of the most used drugs in chemotherapy for a variety of cancers. However, cardiotoxicity limits its use for long periods. To overcome this limitation, encapsulation in smart drug delivery systems (DDS) brings advantages in comparison with free drug administration (i.e., conventional anticancer drug therapy). In this review, we present the most relevant nanostructures used for DOX encapsulation over the last 10 years, such as liposomes, micelles and polymeric vesicles (i.e., polymersomes), micro/nanoemulsions, different types of polymeric nanoparticles and hydrogel nanoparticles, as well as novel approaches for DOX encapsulation. The studies highlighted here show these nanoformulations achieved higher solubility, improved tumor cytotoxicity, prolonged DOX release, as well as reduced side effects, among other interesting advantages.

Therapeutic effect of curcumin in gastrointestinal cancers: A comprehensive review

Gastrointestinal (GI) cancers with a high global prevalence are a leading cause of morbidity and mortality. Accordingly, there is a great need to develop efficient therapeutic approaches. Curcumin, a naturally occurring agent, is a promising compound with documented safety and anticancer activities. Recent studies have demonstrated the activity of curcumin in the prevention and treatment of different cancers. According to systematic studies on curcumin use in various diseases, it can be particularly effective in GI cancers because of its high bioavailability in the gastrointestinal tract. Nevertheless, the clinical applications of curcumin are largely limited because of its low solubility and low chemical stability in water. These limitations may be addressed by the use of relevant analogues or novel delivery systems. Herein, we summarize the pharmacological effects of curcumin against GI cancers. Moreover, we highlight the application of curcumin's analogues and novel delivery systems in the treatment of GI cancers.

The kinetics and release behaviour of curcumin loaded pH-responsive PLGA/chitosan fibers with antitumor activity against HT-29 cells

The bioavailability and clinical effect of curcumin (Cur) are greatly restricted due to its physicochemical instability and high hydrophobicity. To overcome the disadvantages, the nanofibers of poly(lactide-glycolide)/chitosan loaded with Cur (PLGA/CS/Cur) was developed here by electrospinning technique for controlled Cur delivery. The incorporated Cur was well-dispersed and maintained crystalline form in PLGA/CS fiber matrix by hydrogen bonding. The incorporation of Cur had no obvious influence on the fiber size and morphology but exerted impacts on thermal stability. At pH 7.4, the release followed Fickian diffusion mechanism; while at pH 2.0, the release followed the coexistence of diffusion and erosion mechanisms. In addition, the amount of Cur released at pH 2.0 was much higher than that at pH 7.4. As a result, the nanofibers demonstrated higher anticancer activity at acidic environment. Therefore, the PLGA/CS/Cur nanofibers may be served as a potential pH responsive vehicle for the controlled drug delivery.

Tailor-Made Nanomaterials for Diagnosis and Therapy of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers worldwide due to its aggressiveness and the challenge to early diagnosis and treatment. In recent decades, nanomaterials have received increasing attention for diagnosis and therapy of PDAC. However, these designs are mainly focused on the macroscopic tumor therapeutic effect, while the crucial nano-bio interactions in the heterogeneous microenvironment of PDAC remain poorly understood. As a result, the majority of potent nanomedicines show limited performance in ameliorating PDAC in clinical translation. Therefore, exploiting the unique nature of the PDAC by detecting potential biomarkers together with a deep understanding of nano-bio interactions that occur in the tumor microenvironment is pivotal to the design of PDAC-tailored effective nanomedicine. This review will introduce tailor-made nanomaterials-enabled laboratory tests and advanced noninvasive imaging technologies for early and accurate diagnosis of PDAC. Moreover, the fabrication of a myriad of tailor-made nanomaterials for various PDAC therapeutic modalities will be reviewed. Furthermore, much preferred theranostic multifunctional nanomaterials for imaging-guided therapies of PDAC will be elaborated. Lastly, the prospects of these nanomaterials in terms of clinical translation and potential breakthroughs will be briefly discussed.

Targeted polymeric nanoparticles for drug delivery to hypoxic, triple-negative breast tumors

High recurrence and metastasis to vital organs are the major characteristics of triple-negative breast cancer (TNBC). Low vascular oxygen tension promotes resistance to chemo- and radiation therapy. Neuropilin-1 (NRP-1) receptor is highly expressed on TNBC cells. The tumor-penetrating iRGD peptide interacts with the NRP-1 receptor, triggers endocytosis and transcytosis, and facilitates penetration. Herein, we synthesized a hypoxia-responsive diblock PLA-diazobenzene-PEG copolymer and prepared self-assembled hypoxia-responsive polymersomes (Ps) in an aqueous buffer. The iRGD peptide was incorporated into the polymersome structure to make hypoxia-responsive iRGD-conjugated polymersomes (iPs). Doxorubicin (DOX) was encapsulated in the polymersomes to prepare both targeted and non-targeted hypoxia-responsive polymersomes (DOX-iPs and DOX-Ps, respectively). The polymeric nanoparticles released less than 30% of their encapsulated DOX within 12 hours under normoxic conditions (21% oxygen), whereas under hypoxia (2% Oxygen), doxorubicin release remarkably increased to over 95%. The targeted polymersomes significantly decreased TNBC cells' viability in monolayer and spheroid cultures under hypoxia compared to normoxia. Animal studies displayed that targeted polymersomes significantly diminished tumor growth in xenograft nude mice. Overall, the targeted polymersomes exhibited potent anti-tumor activity in monolayer, spheroid, and animal models of TNBC. With further developments, the targeted nanocarriers discussed here might have the translational potential as drug carriers for the treatment of TNBC.

Targeting the Tumor Core: Hypoxia-Responsive Nanoparticles for the Delivery of Chemotherapy to Pancreatic Tumors

In pancreatic ductal adenocarcinoma (PDAC), early onset of hypoxia triggers remodeling of the extracellular matrix, epithelial-to-mesenchymal transition, increased cell survival, the formation of cancer stem cells, and drug resistance. Hypoxia in PDAC is also associated with the development of collagen-rich, fibrous extracellular stroma (desmoplasia), resulting in severely impaired drug penetration. To overcome these daunting challenges, we created polymer nanoparticles (polymersomes) that target and penetrate pancreatic tumors, reach the hypoxic niches, undergo rapid structural destabilization, and release the encapsulated drugs. In vitro studies indicated a high cellular uptake of the polymersomes and increased cytotoxicity of the drugs under hypoxia compared to unencapsulated drugs. The polymersomes decreased tumor growth by nearly 250% and significantly increased necrosis within the tumors by 60% in mice compared to untreated controls. We anticipate that these polymer nanoparticles possess a considerable translational potential for delivering drugs to solid hypoxic tumors.

Emerging era of “somes”: polymersomes as versatile drug delivery carrier for cancer diagnostics and therapy

Over the past two decades, polymersomes have been widely investigated for the delivery of diagnostic and therapeutic agents in cancer therapy. Polymersomes are stable polymeric vesicles, which are prepared using amphiphilic block polymers of different molecular weights. The use of high molecular weight amphiphilic copolymers allows for possible manipulation of membrane characteristics, which in turn enhances the efficiency of drug delivery. Polymersomes are more stable in comparison with liposomes and show less toxicity in vivo. Furthermore, their ability to encapsulate both hydrophilic and hydrophobic drugs, significant biocompatibility, robustness, high colloidal stability, and simple methods for ligands conjugation make polymersomes a promising candidate for therapeutic drug delivery in cancer therapy. This review is focused on current development in the application of polymersomes for cancer therapy and diagnosis. Graphical abstract.

The Impact of obesity and diabetes mellitus on pancreatic cancer: Molecular mechanisms and clinical perspectives

The incidence of obesity and type 2 diabetes (T2DM) in the Western world has increased dramatically during the recent decades. According to the American Cancer Society, pancreatic cancer (PC) is the fourth leading cause of cancer‐related death in the United States. The relationship among obesity, T2DM and PC is complex. Due to increase in obesity, diabetes, alcohol consumption and sedentary lifestyle, the mortality due to PC is expected to rise significantly by year 2040. The underlying mechanisms by which diabetes and obesity contribute to pancreatic tumorigenesis are not well understood. Furthermore, metabolism and microenvironment within the pancreas can also modulate pancreatic carcinogenesis. The risk of PC on a population level may be reduced by modifiable lifestyle risk factors. In this review, the interactions of diabetes and obesity to PC development were summarized, and novel strategies for the prevention and treatment of diabetes and PC were discussed.

Redox dual-stimuli responsive drug delivery systems for improving tumor-targeting ability and reducing adverse side effects

Cancer is a big challenge that has plagued the human beings for ages and one of the most effective treatments is chemotherapy. However, the low tumor-targeting ability limits the wide clinical application of chemotherapy. The microenvironment plays a critical role in many aspects of tumor genesis. It generates the tumor vasculature and it is highly implicated in the progression to metastasis. To maintain a suitable environment for tumor progression, there are special microenvironment in tumor cell, such as low pH, high level of glutathione (GSH) and reactive oxygen species (ROS), and more special enzymes, which is different to normal cell. Microenvironment-targeted therapy strategy could create new opportunities for therapeutic targeting. Compared to other targeting strategies, microenvironment-targeted therapy strategy will control the drug release into tumor cells more accurately. Redox responsive drug delivery systems (DDSs) are developed based on the high level of GSH in tumor cells. However, there are also GSH in normal cell though its level is lower. In order to control the release of drugs more accurately and reduce side effects, other drug release stimuli have been introduced to redox responsive DDSs. Under the synergistic reaction of two stimuli, redox dual-stimuli responsive DDSs will control the release of drugs more accurately and quickly and even increase the accumulation. This review summarizes strategies of redox dual-stimuli responsive DDSs such as pH, light, enzyme, ROS, and magnetic guide to delivery chemotherapeutic agents more accurately, aiming at providing new ideas for further promoting the drug release, enhancing tumor-targeting and improving anticancer effects. To better illustrate the redox dual-stimuli responsive DDS, preparations of carriers are also briefly described in the review.

Organelle-specific targeting of polymersomes into the cell nucleus

Organelle-specific nanocarriers (NCs) are highly sought after for delivering therapeutic agents into the cell nucleus. This necessitates nucleocytoplasmic transport (NCT) to bypass nuclear pore complexes (NPCs). However, little is known as to how comparably large NCs infiltrate this vital intracellular barrier to enter the nuclear interior. Here, we developed nuclear localization signal (NLS)-conjugated polymersome nanocarriers (NLS-NCs) and studied the NCT mechanism underlying their selective nuclear uptake. Detailed chemical, biophysical, and cellular analyses show that karyopherin receptors are required to authenticate, bind, and escort NLS-NCs through NPCs while Ran guanosine triphosphate (RanGTP) promotes their release from NPCs into the nuclear interior. Ultrastructural analysis by regressive staining transmission electron microscopy further resolves the NLS-NCs on transit in NPCs and inside the nucleus. By elucidating their ability to utilize NCT, these findings demonstrate the efficacy of polymersomes to deliver encapsulated payloads directly into cell nuclei.

Biomolecule–polymer hybrid compartments: combining the best of both worlds

Recent advances in bio/polymer hybrid compartments in the quest to obtain artificial cells, biosensors and catalytic compartments.

Enzyme responsive drug delivery systems in cancer treatment

Recent technological approaches in drug delivery have attracted scientist interest for improving therapeutic index of medicines and drug compliance. One of the powerful strategies to control the transportation of drugs is implementation of intelligent stimuli-responsive drug delivery system (DDS). In this regard, tumor tissues with unique characteristics including leaky vasculature and diverse enzyme expression profiles facilitate the development of efficient enzyme-responsive nanoscale delivery systems. Based on the stimuli nature (physical, chemical and biological), these systems can be categorized into three groups according to the nature of trigger initiating the drug release. Enzymes are substantial constituents of the biotechnology toolbox offering promising capabilities and ideal characteristics to accelerate chemical reactions. Nanoparticles which have the ability to trigger their cargo release in the presence of specific enzymes are fabricated implementing fascinating physico-chemical properties of different materials in a nanoscale dimension. In order to reduce the adverse effects of the therapeutic agents, nanocarriers can be utilized and modified with enzyme-labile linkages to provide on-demand enzyme-responsive drug release. In the current review, we give an overview of drug delivery systems which can deliver drugs to the tumor microenvironment and initiate the drug release in response to specific enzymes highly expressed in particular tumor tissues. This strategy offers a versatile platform for intelligent drug release at the site of action.

Threatening cancer with nanoparticle aided combination oncotherapy

Employing combination therapy has become obligatory in cancer cases exhibiting high tumor load, chemoresistant tumor population, and advanced disease stages. Realization of this fact has now led many of the combination oncotherapies to become an integral part of anticancer regimens. Combination oncotherapy may encompass a combination of anticancer agents belonging to a similar therapeutic category or that of different therapeutic categories (e.g. chemotherapy + gene therapy). Differences in the physicochemical properties, pharmacokinetics and biodistribution pattern of different payloads are the major constraints that are faced by combination chemotherapy. Concordant efforts in the field of nanotechnology and oncology have emerged with several approaches to solve the major issues encountered by combination therapy. Unique colloidal behaviors of various types of nanoparticles and differential targeting strategies have accorded an unprecedented ability to optimize combination oncotherapeutic delivery. Nanocarrier based delivery of the various types of payloads such as chemotherapeutic agents and other anticancer therapeutics such as small interfering ribonucleic acid (siRNA), chemosensitizers, radiosensitizers, and antiangiogenic agents have been addressed in the present review. Various nano-delivery systems like liposomes, polymeric nanoparticles, polymerosomes, dendrimers, micelles, lipid based nanoparticles, prodrug based nanocarriers, polymer-drug conjugates, polymer-lipid hybrid nanoparticles, carbon nanotubes, nanosponges, supramolecular nanocarriers and inorganic nanoparticles (gold nanoparticles, silver nanoparticles, magnetic nanoparticles and mesoporous silica based nanoparticles) that have been extensively explored for the formulation of multidrug delivery is an imperative part of discussion in the review. The present review features the outweighing benefits of combination therapy over mono-oncotherapy and discusses several existent nanoformulation strategies that facilitate a successful combination oncotherapy. Several obstacles that may impede in transforming nanotechnology-based combination oncotherapy from bench to bedside, and challenges associated therein have also been discussed in the present review.

Curcumin exerts cytotoxicity dependent on reactive oxygen species accumulation in non-small-cell lung cancer cells

AIM

Curcumin induces cytotoxic cell death in several human cancer cells. Here, we have investigated the effects of curcumin on non-small-cell lung cancer (NSCLC) with an aim to identify underlying mechanisms of its cytotoxic effect.

MATERIALS & METHODS

The effects of various concentrations of curcumin on the NSCLC cell lines A549 and SPC-A1 were evaluated by MTT assay, colony-forming assay and flow cytometry. Additionally, protein expression associated with different signaling pathways was assessed using western blotting.

RESULTS

Curcumin exhibited cytotoxicity against NSCLC, evident from the inhibition of cell proliferation, G2/M arrest, DNA damage, endoplasmic reticulum stress and mitochondrial apoptosis. The anticancer effect was related to reactive oxygen species (ROS) accumulation and could be reversed by ROS scavengers, catalase and N-acetyl-l-cysteine. Curcumin decreased mitochondrial transmembrane potential and induced ROS production, thereby activating the DNA damage/repair pathway and mitochondrial apoptosis.

CONCLUSION

These results indicate that curcumin could be an effective therapeutic candidate for NSCLC.

Biomolecules Turn Self-Assembling Amphiphilic Block Co-polymer Platforms Into Biomimetic Interfaces

Biological membranes constitute an interface between cells and their surroundings and form distinct compartments within the cell. They also host a variety of biomolecules that carry out vital functions including selective transport, signal transduction and cell-cell communication. Due to the vast complexity and versatility of the different membranes, there is a critical need for simplified and specific model membrane platforms to explore the behaviors of individual biomolecules while preserving their intrinsic function. Information obtained from model membrane platforms should make invaluable contributions to current and emerging technologies in biotechnology, nanotechnology and medicine. Amphiphilic block co-polymers are ideal building blocks to create model membrane platforms with enhanced stability and robustness. They form various supramolecular assemblies, ranging from three-dimensional structures (e.g., micelles, nanoparticles, or vesicles) in aqueous solution to planar polymer membranes on solid supports (e.g., polymer cushioned/tethered membranes,) and membrane-like polymer brushes. Furthermore, polymer micelles and polymersomes can also be immobilized on solid supports to take advantage of a wide range of surface sensitive analytical tools. In this review article, we focus on self-assembled amphiphilic block copolymer platforms that are hosting biomolecules. We present different strategies for harnessing polymer platforms with biomolecules either by integrating proteins or peptides into assemblies or by attaching proteins or DNA to their surface. We will discuss how to obtain synthetic structures on solid supports and their characterization using different surface sensitive analytical tools. Finally, we highlight present and future perspectives of polymer micelles and polymersomes for biomedical applications and those of solid-supported polymer membranes for biosensing.

Encapsulation and Delivery of Neutrophic Proteins and Hydrophobic Agents Using PMOXA-PDMS-PMOXA Triblock Polymersomes

Polymersomes are attractive nanocarriers for hydrophilic and lipophilic drugs; they are more stable than liposomes, tunable, and relatively easy to prepare. The copolymer composition and molar mass are critical features that determine the physicochemical properties of the polymersomes including the rate of drug release. We used the triblock-copolymer, poly(2-methyl-2-oxazoline)-block-poly-(dimethysiloxane)-block-poly(2-methyl-2-oxazoline) (PMOXA-PDMS-PMOXA), to form amphipathic polymersomes capable of loading proteins and small hydrophobic agents. The selected agents were unstable neurotrophins (nerve growth factor and brain-derived neurotrophic factor), a large protein CD109, and the fluorescent drug curcumin. We prepared, characterized, and tested polymersomes loaded with selected agents in 2D and 3D biological models. Curcumin-loaded and rhodamine-bound PMOXA-PDMS-PMOXA polymersomes were used to visualize them inside cells. N-Methyl-d-aspartate receptor (NMDAR) agonists and antagonists were also covalently attached to the surface of polymersomes for targeting neurons. Labeled and unlabeled polymersomes with or without loaded agents were characterized using dynamic light scattering (DLS), UV-vis fluorescence spectroscopy, and asymmetrical flow field-flow fractionation (AF4). Polymersomes were imaged and tested for biological activity in human and murine fibroblasts, murine macrophages, primary murine dorsal root ganglia, and murine hippocampal cultures. Polymersomes were rapidly internalized and there was a clear intracellular co-localization of the fluorescent drug (curcumin) with the fluorescent rhodamine-labeled polymersomes. Polymersomes containing CD109, a glycosylphosphatidylinositol-anchored protein, promoted cell migration in the model of wound healing. Nerve growth factor-loaded polymersomes effectively enhanced neurite outgrowth in dissociated and explanted dorsal root ganglia. Brain-derived neurotrophic factor increased dendritic spine density in serum-deprived hippocampal slice cultures. NMDAR agonist- and antagonist-functionalized polymersomes targeted selectively neurons over glial cells in mixed cultures. Collectively, the study reveals the successful incorporation into polymersomes of biologically active trophic factors and small hydrophilic agents that retain their biological activity in vitro, as demonstrated in selected central and peripheral tissue models.

Nanosensors based on polymer vesicles and planar membranes: a short review

This review aims to summarize the advance in the field of nanosensors based on two particular materials: polymer vesicles (polymersomes) and polymer planar membranes. These two types of polymer-based structural arrangements have been shown to be efficient in the production of sensors as their features allow to adapt to different environment but also to increase the sensitivity and the selectivity of the sensing device. Polymersomes and planar polymer membranes offer a platform of choice for a wide range of chemical functionalization and characteristic structural organization which allows a convenient usage in numerous sensing applications. These materials appear as great candidates for such nanosensors considering the broad variety of polymers. They also enable the confection of robust nanosized architectures providing interesting properties for numerous applications in many domains ranging from pollution to drug monitoring. This report gives an overview of these different sensing strategies whether the nanosensors aim to detect chemicals, biological or physical signals.

Synthesis of a Block Copolymer Exhibiting Cell-Responsive Phytochemical Release for Cancer Therapy

Phytochemicals constitute a promising class of therapeutics for the treatment of various diseases, but their delivery poses significant challenges. In this work, a nanoscale polyactive emulsion was designed for smart, cell-responsive delivery of a curcumin prodrug (curcumin dicarboxylate, CDA) that was chemically conjugated to enzymatically labile oligo-peptides with polycaprolactone (PCL) as the carrier. Matrix metalloproteinase (MMP)-sensitive (PLGLYAL) or nonsensitive (GPYYPLG) peptides were used as spacers for conjugating CDA and PCL. This CDA nanoemulsion incorporating the MMP-sensitive sequence exhibited markedly higher anti-cancer activity, cell internalization, and generation of reactive oxygen species in cancer cells in vitro than the control with the nonsensitive oligopeptide. Moreover, the nanopolyactives induced minimal cytotoxicity in noncancerous cell line. This work presents a unique strategy to engineer smart nano-polyactives for efficient and targeted delivery of phytochemicals.

Fluorescent Carbon Quantum Dots with Intrinsic Nucleolus-Targeting Capability for Nucleolus Imaging and Enhanced Cytosolic and Nuclear Drug Delivery

Nucleolus tracking and nucleus-targeted photodynamic therapy are attracting increasing attention due to the importance of nucleolus and the sensitivity of nucleus to various therapeutic stimuli. Herein, a new class of multifunctional fluorescent carbon quantum dots (or carbon dots, CDs) synthesized via the one-pot hydrothermal reaction of m-phenylenediamine and l-cysteine was reported to effectively target nucleolus. The as-prepared CDs possess superior properties, such as low-cost and facile synthesis, good water dispersibility, various surface groups for further modifications, prominent photostability, excellent compatibility, and rapid/convenient/wash-free staining procedures. Besides, as compared with SYTO RNASelect (a commonly used commercial dye for nucleolus imaging) that can only image nucleolus in fixed cells, the CDs can realize high-quality nucleolus imaging in not only fixed cells but also living cells, allowing the real-time tracking of nucleolus-related biological behaviors. Furthermore, after conjugating with protoporphyrin IX (PpIX), a commonly used photosensitizer, the resultant CD-PpIX nanomissiles showed remarkably increased cellular uptake and nucleus-targeting properties and achieved greatly enhanced phototherapeutic efficiency because the nuclei show poor tolerance to reactive oxygen species produced during the photodynamic therapy. The in vivo experiments revealed that the negatively charged CD-PpIX nanomissiles could rapidly and specifically target a tumor site after intravenous injection and cause efficient tumor ablation with no toxic side effects after laser irradiation. It is believed that the present CD-based nanosystem will hold great potential in nucleolus imaging and nucleus-targeted drug delivery and cancer therapy.

Peptide-targeted, stimuli-responsive polymersomes for delivering a cancer stemness inhibitor to cancer stem cell microtumors

Often cancer relapses after an initial response to chemotherapy because of the tumor's heterogeneity and the presence of progenitor stem cells, which can renew. To overcome drug resistance, metastasis, and relapse in cancer, a promising approach is the inhibition of cancer stemness. In this study, the expression of the neuropilin-1 receptor in both pancreatic and prostate cancer stem cells was identified and targeted with a stimuli-responsive, polymeric nanocarrier to deliver a stemness inhibitor (napabucasin) to cancer stem cells. Reduction-sensitive amphiphilic block copolymers PEG₁₉₀₀-S-S-PLA₆₀₀₀ and the N₃-PEG₁₉₀₀-PLA₆₀₀₀ were synthesized. The tumor penetrating iRGD peptide-hexynoic acid conjugate was linked to the N₃-PEG₁₉₀₀-PLA₆₀₀₀ polymer via a Cu²⁺ catalyzed "Click" reaction. Subsequently, this peptide-polymer conjugate was incorporated into polymersomes for tumor targeting and tissue penetration. We prepared polymersomes containing 85% PEG₁₉₀₀-S-S-PLA₆₀₀₀, 10% iRGD-polymer conjugate, and 5% DPPE-lissamine rhodamine dye. The iRGD targeted polymersomes encapsulating the cancer stemness inhibitor napabucasin were internalized in both prostate and pancreatic cancer stem cells. The napabucasin encapsulated polymersomes significantly (p < .05) reduced the viability of both prostate and pancreatic cancer stem cells and decreased the stemness protein expression notch-1 and nanog compared to the control and vesicles without any drug. The napabucasin encapsulated polymersome formulations have the potential to lead to a new direction in prostate and pancreatic cancer therapy by penetrating deeply into the tumors, releasing the encapsulated stemness inhibitor, and killing cancer stem cells.

Asymmetrical Polymer Vesicles for Drug delivery and Other Applications

Scientists have been attracted by polymersomes as versatile drug delivery systems since the last two decades. Polymersomes have the potential to be versatile drug delivery systems because of their tunable membrane formulations, stabilities in vivo, various physicochemical properties, controlled release mechanisms, targeting abilities, and capacities to encapsulate a wide range of drugs and other molecules. Asymmetrical polymersomes are nano- to micro-sized polymeric capsules with asymmetrical membranes, which means, they have different outer and inner coronas so that they can exhibit better endocytosis rate and endosomal escape ability than other polymeric systems with symmetrical membranes. Hence, asymmetrical polymersomes are highly promising as self-assembled nano-delivery systems in the future for in vivo therapeutics delivery and diagnostic imaging applications. In this review, we prepared a summary about recent research progresses of asymmetrical polymersomes in the following aspects: synthesis, preparation, applications in drug delivery and others.