Transferrin-Conjugated Polymeric Nanoparticle for Receptor-Mediated Delivery of Doxorubicin in Doxorubicin-Resistant Breast Cancer Cells

Ligand decorated biodegradable nanomedicine in the treatment of cancer

Cancer is one of the major global health problems, responsible for the second-highest number of deaths. The genetic and epigenetic changes in the oncogenes or tumor suppressor genes alter the regulatory pathways leading to its onset and progression. Conventional methods are used in appropriate combinations for the treatment. Surgery effectively treats localized tumors; however, it fails to treat metastatic tumors, leading to a spread in other organs, causing a high recurrence rate and death. Among the different strategies, the nanocarriers-based approach is highly sought for, but its nonspecific delivery can cause a profound side effect on healthy cells. Targeted nanomedicine has the advantage of targeting cancer cells specifically by interacting with the receptors overexpressed on their surface, overcoming its non-specificity to target healthy cells. Nanocarriers prepared from biodegradable and biocompatible materials are decorated with different ligands by encapsulating therapeutic or diagnostic agents or both to target cancer cells overexpressing the receptors. Scientists are now utilizing a theranostic approach to simultaneously evaluate nanocarrier bio-distribution and its effect on the treatment regime. Herein, we have summarized the recent 5-year efforts in the development of the ligands decorated biodegradable nanocarriers, as a targeted nanomedicine approach, which has been highly promising in the treatment of cancer.

Doxorubicin-transferrin conjugate alters mitochondrial homeostasis and energy metabolism in human breast cancer cells

Doxorubicin (DOX) is considered one of the most powerful chemotherapeutic agents but its clinical use has several limitations, including cardiomyopathy and cellular resistance to the drug. By using transferrin (Tf) as a drug carrier, however, the adverse effects of doxorubicin as well as drug resistance can be reduced. The main objective of this study was to determine the exact nature and extent to which mitochondrial function is influenced by DOX-Tf conjugate treatment, specifically in human breast adenocarcinoma cells. We assessed the potential of DOX-Tf conjugate as a drug delivery system, monitoring its cytotoxicity using the MTT assay and ATP measurements. Moreover, we measured the alterations of mitochondrial function and oxidative stress markers. The effect of DOX-Tf was the most pronounced in MDA-MB-231, triple-negative breast cancer cells, whereas non-cancer endothelial HUVEC-ST cells were more resistant to DOX-Tf conjugate than to free DOX treatment. A different sensitivity of two investigate breast cancer cell lines corresponded to the functionality of their cellular antioxidant systems and expression of estrogen receptors. Our data also revealed that conjugate treatment mediated free radical generation and altered the mitochondrial bioenergetics in breast cancer cells.

Pluronic-based nanovehicles: Recent advances in anticancer therapeutic applications

Pluronics are a class of amphiphilic tri-block copolymers with wide pharmaceutical applicability. In the past decades, the ability to form biocompatible nanosized micelles was exploited to formulate stable drug nanovehicles with potential use in antitumor therapy. Due to the great potential for tuning physical and structural properties of Pluronic unimers, a panoply of drug or polynucleotide-loaded micelles was prepared and tested for their antitumoral activity. The attractive inherent antitumor properties of Pluronic polymers in combination with cell targeting and stimuli-responsive ligands greatly improved antitumoral therapeutic effects of tested drugs. In spite of that, the extraordinary complexity of biological challenges in the delivery of micellar drug payload makes their therapeutic potential still not exploited to the fullest. In this review paper we attempt to present the latest developments in the field of Pluronic based nanovehicles and their application in anticancer therapy with an overview of the chemistry involved in the preparation of these nanovehicles.

A selective drug delivery system based on phospholipid-type nanobubbles for lung cancer therapy

Aim: To develop a micelle-type nanobubble decorated with fluorescein-5-isothiocyanate-conjugated transferrin, with encapsulation of paclitaxel (PTX@FT-NB) for lung cancer treatment. Materials & methods: PTX@FT-NBs were characterized to determine their physicochemical properties, structural stability and cytotoxicity. Lung cancer cell and mouse xenograft tumor models were used to evaluate the therapeutic effectiveness of PTX@FT-NB. Results: The PTX@FT-NBs not only showed selective targeting to lung cancer cells but also inhibited tumor growth significantly via paclitaxel release. Furthermore, paclitaxel-induced microtubule stabilization demonstrated the release of the drug from PTX@FT-NB in the targeted tumor cell both in vitro and in vivo. Conclusion: PTX@FT-NB has the potential as an anticancer nanocarrier against lung cancer cells because of its specific targeting and better drug delivery capacity.

Receptor-based targeting of engineered nanocarrier against solid tumors: Recent progress and challenges ahead

Background In past few decades, the research on engineered nanocarriers (NCs) has gained significant attention in cancer therapy due to selective delivery of drug molecules on the diseased cells thereby preventing unwanted uptake into healthy cells to cause toxicity. Scope of review The applicability of enhanced permeability and retention (EPR) effect for the delivery of nanomedicines in cancer therapy has gained limited success due to poor accessibility of the drugs to the target cells where non-specific payload delivery to the off target region lack substantial reward over the conventional therapeutic systems. Major conclusions In spite of the fact, nanomedicines fabricated from the biocompatible nanocarriers have reduced targeting potential for meaningful clinical benefits. However, over expression of receptors on the tumor cells provides opportunity to design functional nanomedicine to bind substantially and deliver therapeutics to the cells or tissues of interest by alleviating the bio-toxicity and unwanted effects. This critique will give insight into the over expressed receptor in various tumor and targeting potential of functional nanomedicine as new therapeutic avenues for effective treatment. General significance This review shortly shed light on EPR-based drug targeting using nanomedicinal strategies, their limitation, and advances in therapeutic targeting to the tumor cells.

Folate-Targeted Cholesterol-Grafted Lipo-Polymeric Nanoparticles for Chemotherapeutic Agent Delivery

Docetaxel (DTX), an FDA approved chemotherapeutic agent, is used as a first-line treatment for triple-negative breast cancer (TNBC). Its poor aqueous solubility, rapid metabolism, short half-life, and effective targeting to the cancer cells limits its optimal therapeutic use. Herein, we report folate targeted amphiphilic lipopolymer grafted with cholesterol conjugated carbonate and DL-lactide prepared by microwave assisted ring opening polymerization, for the efficient actively targeted delivery of DTX. The DTX-loaded folate-targeted lipopolymeric nanoparticles (F-DTX-LPNs) prepared by the emulsion solvent evaporation method exhibited a smaller size of ∼115.17 nm with a PDI of 0.205 and encapsulation efficiency of >80%. Further, these lipopolymeric nanoparticles (F-DTX-LPNs) showed a good on-bench stability and sustained DTX release for 7 days. Cell-based assays in MDA-MB-231 cells revealed a significant enhancement in the intracellular uptake of folate-targeted lipopolymeric nanoparticles compared to non-targeted nanoparticles. Further, methyl beta-cyclodextrin (Mβ-CD) completely inhibited the uptake of these nanoparticles in the cells, indicating a lipid raft-mediated uptake mechanism. The developed F-DTX-LPNs showed improved cytotoxicity, apoptosis, and significant fold-change in expression levels of Bcl-2, BAX and Ki-67 as compared to non-targeted DTX-LPNs and free DTX. Further, F-DTX-LPNs showed an improved in vivo pharmacokinetic profile in Sprague Dawley rats as compared to the free DTX. The bio-imaging of ex vivo tissues demonstrated that the DiR loaded folate targeted LPNs exhibited intense signals after 24 h because of slow release of DiR dye from the nanoparticles.

Surface-functionalised hybrid nanoparticles for targeted treatment of cancer

Cancer is a leading cause of death worldwide. Despite the great advancement in understanding the pharmacology and biology of cancer, it still signifies one of the most serious human-health related problems. The current treatments for cancer may include surgery, radiotherapy, and chemotherapy, but these procedures have several limitations. Current studies have shown that nanoparticles (NPs) can be used as a novel strategy for cancer treatment. Developing nanosystems that allow lower doses of therapeutic agents, as well as their selective release in tumour cells, may resolve the challenges of targeted cancer therapy. In this review, the authors discuss the role of the size, shape, and surface modifications of NPs in cancer treatment. They also address the challenges associated with cancer therapies based on NPs. The overall purpose of this review is to summarise the recent developments in designing different hybrid NPs with promising therapeutic properties for different types of cancer.

Nanoparticle-Based Drug Delivery in Cancer Therapy and Its Role in Overcoming Drug Resistance

Nanotechnology has been extensively studied and exploited for cancer treatment as nanoparticles can play a significant role as a drug delivery system. Compared to conventional drugs, nanoparticle-based drug delivery has specific advantages, such as improved stability and biocompatibility, enhanced permeability and retention effect, and precise targeting. The application and development of hybrid nanoparticles, which incorporates the combined properties of different nanoparticles, has led this type of drug-carrier system to the next level. In addition, nanoparticle-based drug delivery systems have been shown to play a role in overcoming cancer-related drug resistance. The mechanisms of cancer drug resistance include overexpression of drug efflux transporters, defective apoptotic pathways, and hypoxic environment. Nanoparticles targeting these mechanisms can lead to an improvement in the reversal of multidrug resistance. Furthermore, as more tumor drug resistance mechanisms are revealed, nanoparticles are increasingly being developed to target these mechanisms. Moreover, scientists have recently started to investigate the role of nanoparticles in immunotherapy, which plays a more important role in cancer treatment. In this review, we discuss the roles of nanoparticles and hybrid nanoparticles for drug delivery in chemotherapy, targeted therapy, and immunotherapy and describe the targeting mechanism of nanoparticle-based drug delivery as well as its function on reversing drug resistance.

Nanoparticle-Based Drug Delivery in Cancer Therapy and Its Role in Overcoming Drug Resistance

Nanotechnology has been extensively studied and exploited for cancer treatment as nanoparticles can play a significant role as a drug delivery system. Compared to conventional drugs, nanoparticle-based drug delivery has specific advantages, such as improved stability and biocompatibility, enhanced permeability and retention effect, and precise targeting. The application and development of hybrid nanoparticles, which incorporates the combined properties of different nanoparticles, has led this type of drug-carrier system to the next level. In addition, nanoparticle-based drug delivery systems have been shown to play a role in overcoming cancer-related drug resistance. The mechanisms of cancer drug resistance include overexpression of drug efflux transporters, defective apoptotic pathways, and hypoxic environment. Nanoparticles targeting these mechanisms can lead to an improvement in the reversal of multidrug resistance. Furthermore, as more tumor drug resistance mechanisms are revealed, nanoparticles are increasingly being developed to target these mechanisms. Moreover, scientists have recently started to investigate the role of nanoparticles in immunotherapy, which plays a more important role in cancer treatment. In this review, we discuss the roles of nanoparticles and hybrid nanoparticles for drug delivery in chemotherapy, targeted therapy, and immunotherapy and describe the targeting mechanism of nanoparticle-based drug delivery as well as its function on reversing drug resistance.

Pediatric glioblastoma target-specific efficient delivery of gemcitabine across the blood-brain barrier via carbon nitride dots

Pediatric glioblastomas are known to be one of the most dangerous and life-threatening cancers among many others regardless of the low number of cases reported. The major obstacles in the treatment of these tumors can be identified as the lack of prognosis data and the therapeutic requirement to be able to cross the blood-brain barrier (BBB). Due to this lack of data and techniques, pediatric patients could face drastic side effects over a long-time span even after survival. Therefore, in this study, the capability of non-toxic carbon nitride dots (CNDs) to selectively target pediatric glioblastoma cells was studied in vitro. Furthermore, the nanocarrier capability and efficiency of CNDs were also investigated through conjugation of a chemotherapeutic agent and transferrin (T_f) protein. Gemcitabine (GM) was introduced into the system as a chemotherapeutic agent, which has never been successfully used for the treatment of any central nervous system (CNS) cancer. More than 95% of selective damage of SJGBM2 glioma cells was observed at 1 μM of CN-GM conjugate with almost 100% viability of non-cancerous HEK293 cells, although this ability was diminished at lower concentrations. However, further conjugation of T_f to obtain CN-GM-T_f allowed the achievement of selective targeting and prominent anti-cancer activity at a 100-fold lower concentration of 10 nM. Furthermore, both conjugates were capable of effectively damaging several other brain tumor cells, which were not well responsive towards the single treatment of GM. The capability of BBB penetration of the conjugates was observed using a zebrafish model, which confirms the CNDs' competence as an excellent nanocarrier to the CNS.

Development of Copper Nanoclusters for In Vitro and In Vivo Theranostic Applications

Theranostics refers to the incorporation of therapeutic and diagnostic functions into one material system. An important class of nanomaterials exploited for theranostics is metal nanoclusters (NCs). In contrast to gold and silver NCs, copper is an essential trace element for humans. It can be more easily removed from the body. This, along with the low cost of copper that offers potential large-scale nanotechnology applications, means that copper NCs have attracted great interest in recent years. The latest advances in the design, synthesis, surface engineering, and applications of copper NCs in disease diagnosis, monitoring, and treatment are reviewed. Strategies to control and enhance the emission of copper NCs are considered. With this synopsis of the up-to-date development of copper NCs as theranostic agents, it is hoped that insights and directions for translating current advances from the laboratory to the clinic can be further advanced and accelerated.

Improvement of conventional anti-cancer drugs as new tools against multidrug resistant tumors

Multidrug resistance (MDR) is the dominant cause of the failure of cancer chemotherapy. The design of antitumor drugs that are able to evade MDR is rapidly evolving, showing that this area of biomedical research attracts great interest in the scientific community. The current review explores promising recent approaches that have been developed with the aim of circumventing or overcoming MDR. Encouraging results have been obtained in the investigation of the MDR-modulating properties of various classes of natural compounds and their analogues. Inhibition of P-gp or downregulation of its expression have proven to be the main mechanisms by which MDR can be surmounted. The use of hybrid molecules that are able to simultaneously interact with two or more cancer cell targets is currently being explored as a means to circumvent drug resistance. This strategy is based on the design of hybrid compounds that are obtained either by merging the structural features of separate drugs, or by conjugating two drugs or pharmacophores via cleavable/non-cleavable linkers. The approach is highly promising due to the pharmacokinetic and pharmacodynamic advantages that can be achieved over the independent administration of the two individual components. However, it should be stressed that the task of obtaining successful multivalent drugs is a very challenging one. The conjugation of anticancer agents with nitric oxide (NO) donors has recently been developed, creating a particular class of hybrid that can combat tumor drug resistance. Appropriate NO donors have been shown to reverse drug resistance via nitration of ABC transporters and by interfering with a number of metabolic enzymes and signaling pathways. In fact, hybrid compounds that are produced by covalently attaching NO-donors and antitumor drugs have been shown to elicit a synergistic cytotoxic effect in a variety of drug resistant cancer cell lines. Another strategy to circumvent MDR is based on nanocarrier-mediated transport and the controlled release of chemotherapeutic drugs and P-gp inhibitors. Their pharmacokinetics are governed by the nanoparticle or polymer carrier and make use of the enhanced permeation and retention (EPR) effect, which can increase selective delivery to cancer cells. These systems are usually internalized by cancer cells via endocytosis and accumulate in endosomes and lysosomes, thus preventing rapid efflux. Other modalities to combat MDR are described in this review, including the pharmaco-modulation of acridine, which is a well-known scaffold in the development of bioactive compounds, the use of natural compounds as means to reverse MDR, and the conjugation of anticancer drugs with carriers that target specific tumor-cell components. Finally, the outstanding potential of in silico structure-based methods as a means to evaluate the ability of antitumor drugs to interact with drug transporters is also highlighted in this review. Structure-based design methods, which utilize 3D structural data of proteins and their complexes with ligands, are the most effective of the in silico methods available, as they provide a prediction regarding the interaction between transport proteins and their substrates and inhibitors. The recently resolved X-ray structure of human P-gp can help predict the interaction sites of designed compounds, providing insight into their binding mode and directing possible rational modifications to prevent them from becoming P-gp drug substrates. In summary, although major efforts were invested in the search for new tools to combat drug resistant tumors, they all require further implementation and methodological development. Further investigation and progress in the abovementioned strategies will provide significant advances in the rational combat against cancer MDR.

Nanomedicine in treatment of breast cancer - A challenge to conventional therapy

Amongst the various types of cancer, breast cancer is a highly heterogeneous disease and known as the leading cause of death among women globally. The extensive interdisciplinary investigation in nanotechnology and cancer biomedical research has been evolved over the years for its effective treatment. However, the advent of chemotherapeutic resistance in breast cancer is one of the major confront researchers are facing in achieving successful chemotherapy. Research in the area of cancer nanotechnology over the years have now been revolutionized through the development of smart polymers, lipids, inorganic materials and eventually their surface-engineering with targeting ligands. Moreover, nanotechnology further extended and brings in the notice the new theranostic approach which combining the therapy and imaging simultaneously. Currently, research is being envisaged in the area of novel nano-pharmaceutical design viz. liposome, nanotubes, polymer lipid hybrid system, which focuses to make the chemotherapy curative and long-lasting. In this review, we aimed to discuss the recent advancement of different surface-engineered/targeted nanomedicines that improved the drug efficacy in breast cancer.

Folate Receptor α-Modified Nanoparticles for Targeting of the Central Nervous System

Effective and timely delivery of therapeutic agents from the systemic circulation to the central nervous system (CNS) is often precluded by the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB). A new pathway of folate uptake mediated by folate receptor alpha (FRα, molecular weight of 28.29 kg mol^-1) occurring in various epithelial cells of the CNS (e.g., choroid plexus) was described. Aiming to investigate this mechanism for the delivery of nanomedicines to the CNS, in this work, we initially produced nanoparticles (NPs) made of a highly hydrophobic poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG-b-PCL) block copolymer functionalized with an amine moiety in the edge of the PEG block by a simple nanoprecipitation method. Hydrophilic PEG blocks migrated to the NP surface during formation, exposing primary amine groups that were used to conjugate the targeting ligand, FRα. The size of the NPs was in the 58-98 nm range and standard deviation (S.D., a measure of the size population peak width) of 26-41 nm, as measured by dynamic light scattering (DLS). The FRα conjugation yield ranged between 50% and 75% (determined indirectly by the bicinchoninic acid protein assay). Pristine and FRα-modified NPs showed good compatibility with primary human choroid plexus epithelial cells (HCPEpiCs). The uptake of FRα-conjugated NPs by HCPEpiCs was qualitatively evaluated in vitro using inverted optical fluorescence and confocal microscopy. FRα-modified NPs were internalized by HCPEpiCs to a greater extent than the unmodified counterparts. Then, their permeability was characterized in standard and inverted HCPEpiC monolayers. In both cases, NPs surface modified with the FRα and complexed to folic acid (FA) showed significantly higher apparent permeability coefficient (P_app) values than the pristine ones. Finally, the biodistribution of unmodified and FRα-FA-modified NPs following intravenous (i.v.) administration was compared in ICR mice. Results indicated that conjugation of the FRα-FA complex to the NP surface promotes higher accumulation in the brain, highlighting the promise of FRα-FA-modified NPs to serve as a platform for the targeting of active molecules to the CNS from the systemic circulation.

Non-small cell lung cancer-targeted, redox-sensitive lipid-polymer hybrid nanoparticles for the delivery of a second-generation irreversible epidermal growth factor inhibitor-Afatinib: In vitro and in vivo evaluation

Afatinib (Afa), a second-generation irreversible epidermal growth factor inhibitor for the development of non-small cell lung cancer, has low bioavailability and adverse reactions. Nanoscaled drug delivery systems offer promising alternatives to address these defects and improve therapeutic outcomes. In the present study, a Tf contained, redox-sensitive ligand was synthesized and used for the preparation of afatinib loaded, Tf modified redox-sensitive lipid-polymer hybrid nanoparticles (Tf-SS-Afa-LPNs). Subsequently, studies of biological experiments in vitro and in vivo were performed to investigate the therapeutic effect of the system in lung cancer. The results showed that Tf-SS-Afa-LPNs has particle size of 103.5 ± 4.1 nm and zeta potential of -21.2 ± 2.4 mV. Significantly higher drug release was observed in the presence of glutathione (GSH). The area under the plasma concentration - time curve (AUC), peak concentration (C_max) and terminal half life (T_1/2) of Tf-SS-Afa-LPNs were 866.56 mg/L.h, 25.62 ± 3.21 L/kg/h, and 43.25 ± 2.31 h. Tf-SS-Afa-LPNs exhibited the most remarkable in vivo anti-tumor efficiency efficacy, which inhibited the tumor volume from 919 mm³ to 212 mm³. Tf-SS-Afa-LPNs is a promising platform for the lung cancer treatment.