Specific Targeting of HER2 Overexpressing Breast Cancer Cells with Doxorubicin-Loaded Trastuzumab-Modified Human Serum Albumin Nanoparticles

A comprehensive review on doxorubicin: mechanisms, toxicity, clinical trials, combination therapies and nanoformulations in breast cancer

Doxorubicin is a key treatment for breast cancer, but its effectiveness often comes with significant side effects. Its actions include DNA intercalation, topoisomerase II inhibition, and reactive oxygen species generation, leading to DNA damage and cell death. However, it can also cause heart problems and low blood cell counts. Current trials aim to improve doxorubicin therapy by adjusting doses, using different administration methods, and combining it with targeted treatments or immunotherapy. Nanoformulations show promise in enhancing doxorubicin's effectiveness by improving drug delivery, reducing side effects, and overcoming drug resistance. This review summarizes recent progress and difficulties in using doxorubicin for breast cancer, highlighting its mechanisms, side effects, ongoing trials, and the potential impact of nanoformulations. Understanding these different aspects is crucial in optimizing doxorubicin's use and improving outcomes for breast cancer patients. This review examines the toxicity of doxorubicin, a drug used in breast cancer treatment, and discusses strategies to mitigate adverse effects, such as cardioprotective agents and liposomal formulations. It also discusses clinical trials evaluating doxorubicin-based regimens, the evolving landscape of combination therapies, and the potential of nanoformulations to optimize delivery and reduce systemic toxicity. The review also discusses the potential of liposomes, nanoparticles, and polymeric micelles to enhance drug accumulation within tumor tissues while sparing healthy organs.

Nanozymes: a new approach for leukemia therapy

Leukemia is a type of clonal disorder of hematopoietic stem and progenitor cells characterized by bone marrow failure, differentiation arrest, and lineage skewing. Despite leukemia being a complex disease and it being difficult to identify a single driving force, redox homeostasis, the balance between reactive oxygen species (ROS) producers and cellular antioxidant systems, is normally impaired during leukemogenesis. In this context, the modulation of ROS in leukemia cells can be harnessed for therapeutic purposes. Nanozymes are functional nanomaterials with enzyme-like characteristics, which address the intrinsic limitations of natural enzymes and exhibit great potential in synergistic antitumor therapy. Nanozymes possess catalytic activities (e.g., peroxidase-like activity, catalase-like activity, superoxide dismutase-like activity, and oxidase-like activity) to regulate ROS levels in vitro and in vivo, making them promising for leukemia therapy. On account of the rapid development of nanozymes recently, their application potentials in leukemia therapy are gradually being explored. To highlight the achievements of nanozymes in the leukemia field, this review summarizes the recent studies of nanozymes with anti-leukemia efficacy and the underlying mechanism. In addition, the challenges and prospects of nanozyme research in leukemia therapy are discussed.

Use of Albumin for Drug Delivery as a Diagnostic and Therapeutic Tool

Drug delivery is an important topic that has attracted the attention of researchers in recent years. Albumin nanoparticles play a significant role in drug delivery as a carrier due to their unique characteristics. Albumin is non-toxic, biocompatible, and biodegradable. Its structure is such that it can interact with different drugs, which makes the treatment of the disease faster and also reduces the side effects of the drug. Albumin nanoparticles can be used in the diagnosis and treatment of many diseases, including cancer, diabetes, Alzheimer's, etc. These nanoparticles can connect to some compounds, such as metal nanoparticles, antibodies, folate, etc. and create a powerful nanostructure for drug delivery. In this paper, we aim to investigate albumin nanoparticles in carrier format for drug delivery application. In the beginning, different types of albumin and their preparation methods were discussed, and then albumin nanoparticles were discussed in detail in diagnosing and treating various diseases.

Radiolabeled Human Serum Albumin Nanoparticles Co-Loaded with Methotrexate and Decorated with Trastuzumab for Breast Cancer Diagnosis

Breast cancer is a leading cause of cancer-related mortality among women worldwide, with millions of new cases diagnosed yearly. Addressing the burden of breast cancer mortality requires a comprehensive approach involving early detection, accurate diagnosis, effective treatment, and equitable access to healthcare services. In this direction, nano-radiopharmaceuticals have shown potential for enhancing breast cancer diagnosis by combining the benefits of nanoparticles and radiopharmaceutical agents. These nanoscale formulations can provide improved imaging capabilities, increased targeting specificity, and enhanced sensitivity for detecting breast cancer lesions. In this study, we developed and evaluated a novel nano-radio radiopharmaceutical, technetium-99m ([99mTc]Tc)-labeled trastuzumab (TRZ)-decorated methotrexate (MTX)-loaded human serum albumin (HSA) nanoparticles ([99mTc]-TRZ-MTX-HSA), for the diagnosis of breast cancer. In this context, HSA and MTX-HSA nanoparticles were prepared. Conjugation of MTX-HSA nanoparticles with TRZ was performed using adsorption and covalent bonding methods. The prepared formulations were evaluated for particle size, PDI value, zeta (ζ) potential, scanning electron microscopy analysis, encapsulation efficiency, and loading capacity and cytotoxicity on MCF-7, 4T1, and MCF-10A cells. Finally, the nanoparticles were radiolabeled with [99mTc]Tc using the direct radiolabeling method, and cellular uptake was performed with the nano-radiopharmaceutical. The results showed the formation of spherical nanoparticles, with a particle size of 224.1 ± 2.46 nm, a PDI value of 0.09 ± 0.07, and a ζ potential value of -16.4 ± 0.53 mV. The encapsulation efficiency of MTX was found to be 32.46 ± 1.12%, and the amount of TRZ was 80.26 ± 1.96%. The labeling with [99mTc]Tc showed a high labeling efficiency (>99%). The cytotoxicity studies showed no effect, and the cellular uptake studies showed 97.54 ± 2.16% uptake in MCF-7 cells at the 120th min and were found to have a 3-fold higher uptake in cancer cells than in healthy cells. In conclusion, [99mTc]Tc-TRZ-MTX-HSA nanoparticles are promising for diagnosing breast cancer and evaluating the response to treatment in breast cancer patients.

Quetiapine Albumin Nanoparticles as an Efficacious Platform for Brain Deposition and Potentially Improved Antipsychotic Activity

Quetiapine (QP) is a second-generation short-acting antipsychotic drug extensively metabolized in the liver, producing pharmacologically inactive metabolites and leading to diminished bioavailability. Therefore, this study aimed to develop an intravenous QP albumin nanoparticles (NPs) system for improving QP antipsychotic activity and brain targeting. QP-loaded albumin NPs were prepared by the desolvation method. The fabricated NPs were characterized in terms of particle size, zeta potential, entrapment efficiency (EE%), and in vitro drug release. In vivo pharmacokinetics and biodistribution in rats were studied. In addition, the antipsychotic activity of the optimized platform was also investigated. Human serum albumin (HSA) concentration, pH, and stirring time were modulated to optimize QP albumin NPs with a particle size of 103.54 ± 2.36 nm and a QP EE% of 96.32 ± 3.98%. In addition, the intravenous administration of QP albumin NPs facilitated QP brain targeting with a 4.9-fold increase in targeting efficiency compared to the oral QP solution. The QP albumin NPs improved the QP antipsychotic activity, indicated by suppressing rats' hypermobility and reducing the QP's extrapyramidal side effects. The obtained results proposed that intravenous QP- NPs could improve QP brain targeting and its antipsychotic efficiency.

Impact of Nanomedicine in Women's Metastatic Breast Cancer

Metastatic breast cancer is responsible for 90% of mortalities among women suffering from various types of breast cancers. Traditional cancer treatments such as chemotherapy and radiation therapy can cause significant side effects and may not be effective in many cases. However, recent advances in nanomedicine have shown great promise in the treatment of metastatic breast cancer. For example, nanomedicine demonstrated robust capacity in detection of metastatic cancers at early stages (i.e., before the metastatic cells leave the initial tumor site), which gives clinicians a timely option to change their treatment process (for example, instead of endocrine therapy they may use chemotherapy). Here recent advances in nanomedicine technology in the identification and treatment of metastatic breast cancers are reviewed.

Principles of Nanoparticle Delivery to Solid Tumors

The effective treatment of patients with cancer hinges on the delivery of therapeutics to a tumor site. Nanoparticles provide an essential transport system. We present 5 principles to consider when designing nanoparticles for cancer targeting: (a) Nanoparticles acquire biological identity in vivo, (b) organs compete for nanoparticles in circulation, (c) nanoparticles must enter solid tumors to target tumor components, (d) nanoparticles must navigate the tumor microenvironment for cellular or organelle targeting, and (e) size, shape, surface chemistry, and other physicochemical properties of nanoparticles influence their transport process to the target. This review article describes these principles and their application for engineering nanoparticle delivery systems to carry therapeutics to tumors or other disease targets.

Antibody-Incorporated Nanomedicines for Cancer Therapy

Antibody-based cancer therapy, one of the most significant therapeutic strategies, has achieved considerable success and progress over the past decades. Nevertheless, obstacles including limited tumor penetration, short circulation half-lives, undesired immunogenicity, and off-target side effects remain to be overcome for the antibody-based cancer treatment. Owing to the rapid development of nanotechnology, antibody-containing nanomedicines that have been extensively explored to overcome these obstacles have already demonstrated enhanced anticancer efficacy and clinical translation potential. This review intends to offer an overview of the advancements of antibody-incorporated nanoparticulate systems in cancer treatment, together with the nontrivial challenges faced by these next-generation nanomedicines. Diverse strategies of antibody immobilization, formats of antibodies, types of cancer-associated antigens, and anticancer mechanisms of antibody-containing nanomedicines are provided and discussed in this review, with an emphasis on the latest applications. The current limitations and future research directions on antibody-containing nanomedicines are also discussed from different perspectives to provide new insights into the construction of anticancer nanomedicines.

Targeted delivery of albumin nanoparticles for breast cancer: A review

Breast cancer has been identified as one of the most common cancers diagnosed in women. Various nanotechnology platforms offering unique features are considered in breast cancer treatment. Albumin is a versatile biodegradable, biocompatible, non-toxic and non-immunogenic protein nanocarrier. These characteristics attracted strong attention to fabricate albumin nanoparticles to deliver chemotherapeutic agents without major adverse effects. Albumin nanoparticles can undergo surface modifications using different ligands promoting tumor-targeted drug delivery. Moreover, multifunctional albumin nanoparticle is an upcoming strategy to attain efficient cancer therapy. This review gives an account of the potential albumin nanoparticles developed for chemotherapeutic drug delivery and its targeted approach for breast cancer. It also covers different multifunctional therapies available using albumin nanoparticles as breast cancer theranostics.

Emerging Albumin-Binding Anticancer Drugs for Tumor-Targeted Drug Delivery: Current Understandings and Clinical Translation

Albumin has shown remarkable promise as a natural drug carrier by improving pharmacokinetic (PK) profiles of anticancer drugs for tumor-targeted delivery. The exogenous or endogenous albumin enhances the circulatory half-lives of anticancer drugs and passively target the tumors by the enhanced permeability and retention (EPR) effect. Thus, the albumin-based drug delivery leads to a potent antitumor efficacy in various preclinical models, and several candidates have been evaluated clinically. The most successful example is Abraxane, an exogenous human serum albumin (HSA)-bound paclitaxel formulation approved by the FDA and used to treat locally advanced or metastatic tumors. However, additional clinical translation of exogenous albumin formulations has not been approved to date because of their unexpectedly low delivery efficiency, which can increase the risk of systemic toxicity. To overcome these limitations, several prodrugs binding endogenous albumin covalently have been investigated owing to distinct advantages for a safe and more effective drug delivery. In this review, we give account of the different albumin-based drug delivery systems, from laboratory investigations to clinical applications, and their potential challenges, and the outlook for clinical translation is discussed. In addition, recent advances and progress of albumin-binding drugs to move more closely to the clinical settings are outlined.

Recent advances in nanoscale targeted therapy of HER2-positive breast cancer

Breast cancer is the second leading cause of death among women with high mortality rates worldwide. The exceptionally fast rate of metastasis, the emergence of drug-resistant mechanisms, and the occurrence of inadvertent side effects by cytotoxic chemotherapies often make conventional chemotherapy and immunotherapy treatments ineffective. Similar to other solid tumors, breast cancer can develop unique cellular and molecular characteristics forming an atypical permissive tumor microenvironment (TME). Due to the unique features of TME, cancer cells can further proliferate and coadapt with the stromal cells and evade immunosurveillance. aberrantly abundantly express various pieces of molecular machinery (the so-called oncomarkers) in favor of their survival, progression, metastasis, and further invasion. Such overexpressed oncomarkers can be exploited in the targeted therapy of cancer. Among breast cancer oncomarkers, epidermal growth factor receptors, particularly HER2, are considered as clinically valid molecular targets not only for the thorough diagnosis but also for the targeted therapy of the disease using different conventional and advanced nanoscale treatment modalities. This review aims to elaborate on the recent advances in the targeted therapy of HER2-positive breast cancer, and discuss various types of multifunctional nanomedicines/theranostics, and antibody-/aptamer-drug conjugates.

Actively Targeted Nanomedicines in Breast Cancer: From Pre-Clinal Investigation to Clinic

Simple Summary

Despite all the efforts and advances made in the treatment of breast cancer, this pathology continues to be one of the main causes of cancer death in women, particularly triple-negative breast cancer (TNBC), and, although to a lesser degree, HER-2 receptor-positive tumors. Chemotherapy is one of the main treatments available. However, it shows numerous limitations due to its lack of selectivity. In this sense, the selective delivery of antineoplastics to cancer cells can reduce their adverse effects and increase their efficacy. The use of active targeted nanomedicine is a good strategy to achieve this selective chemotherapy. In fact, in recent decades, several active targeted nanoformulations have been approved or reached clinical investigation with excellent results. Among all nanomedicines, antibody-drug conjugates are the most promising.

Abstract

Breast cancer is one of the most frequently diagnosed tumors and the second leading cause of cancer death in women worldwide. The use of nanosystems specifically targeted to tumor cells (active targeting) can be an excellent therapeutic tool to improve and optimize current chemotherapy for this type of neoplasm, since they make it possible to reduce the toxicity and, in some cases, increase the efficacy of antineoplastic drugs. Currently, there are 14 nanomedicines that have reached the clinic for the treatment of breast cancer, 4 of which are already approved (Kadcyla^®, Enhertu^®, Trodelvy^®, and Abraxane^®). Most of these nanomedicines are antibody–drug conjugates. In the case of HER-2-positive breast cancer, these conjugates (Kadcyla^®, Enhertu^®, Trastuzumab-duocarmycin, RC48, and HT19-MMAF) target HER-2 receptors, and incorporate maytansinoid, deruxtecan, duocarmicyn, or auristatins as antineoplastics. In TNBC these conjugates (Trodelvy^®, Glembatumumab-Vedotin, Ladiratuzumab-vedotin, Cofetuzumab-pelidotin, and PF-06647263) are directed against various targets, in particular Trop-2 glycoprotein, NMB glycoprotein, Zinc transporter LIV-1, and Ephrin receptor-4, to achieve this selective accumulation, and include campthotecins, calicheamins, or auristatins as drugs. Apart from the antibody–drug conjugates, there are other active targeted nanosystems that have reached the clinic for the treatment of these tumors such as Abraxane^® and Nab-rapamicyn (albumin nanoparticles entrapping placlitaxel and rapamycin respectively) and various liposomes (MM-302, C225-ILS-Dox, and MM-310) loaded with doxorubicin or docetaxel and coated with ligands targeted to Ephrin A2, EPGF, or HER-2 receptors. In this work, all these active targeted nanomedicines are discussed, analyzing their advantages and disadvantages over conventional chemotherapy as well as the challenges involved in their lab to clinical translation. In addition, examples of formulations developed and evaluated at the preclinical level are also discussed.

Spacer length and serum protein adsorption affect active targeting of trastuzumab-modified nanoparticles

Receptor-mediated active targeting of nanocarriers is a widely investigated approach to specifically address cancerous cells and tissues in the human body. The idea is to use these formulations as drug carriers with enhanced specificity and therefore reduced systemic side effects. Until today a big obstacle to reach this goal remains the adsorption of serum proteins to the nanocarrier's surface after contact with biological fluids. In this context different nanoparticle characteristics could be beneficial for effective active targeting after formation of a protein corona which need to be identified. In this study trastuzumab was used as an active targeting ligand which was covalently attached to human serum albumin nanoparticles. For coupling reaction different molecular weight spacers were used and resulting physicochemical nanoparticle characteristics were evaluated. The in vitro cell association of the different nanoparticle formulations was tested in cell culture experiments with or without fetal bovine serum. For specific receptor-mediated cell interaction SK-BR-3 breast cancer cells with human epidermal growth factor receptor 2 (HER2) overexpression were used. MCF-7 breast cancer cells with normal HER2 expression served as control. Furthermore, serum protein adsorption on respective nanoparticles was characterized. The qualitative and quantitative composition of the protein corona was analyzed by SDS-PAGE and LC-MS/MS and the influence of protein adsorption on active targeting capability was determined.

Development of HER2-Targeting-Ligand-Modified Albumin Nanoparticles Based on the SpyTag/SpyCatcher System for Photothermal Therapy

The successful development of targeted nanoparticle (NP)-based therapeutics depends on the effective conjugation of targeting ligands to the NP. However, conventional methods based on chemical reactive groups such as N-hydroxysuccinimide, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, and maleimide have several limitations, including low binding efficiency, complex reaction methods, long reaction times, and reduced activity of the targeting ligand. In this study, we developed a novel method for conjugating targeting ligands to albumin NPs using the recently developed bacterial superglue the SpyTag/SpyCatcher (ST/SC) ligation system. This method involves a rapid one-step conjugation process with almost 100% efficiency. Albumin NPs conjugated to human epidermal growth factor receptor 2 (HER2) affibody molecules using the ST/SC system showed strong binding to HER2-overexpressing cells. In addition, NPs encapsulated with indocyanine green accumulated in cells overexpressing HER2 and exhibited superior photothermal treatment effects. Thus, surface functionalization of NPs using the ST/SC reaction may be used to develop new nanosystems that exhibit improved therapeutic benefits.

Advances in receptor modulation strategies for flexible, efficient, and enhanced antitumor efficacy

Tumor-sensitivity, effective transport, and precise delivery to tumor cells of nano drug delivery systems (NDDs) have been great challenges to cancer therapy in recent years. The conventional targeting approach involves actively installing the corresponding ligand on the nanocarriers, which is prone to recognize the antigen blasts overexpressed on the surface of tumor cells. However, there are some probable limitations for the active tumor-targeting systems in vivo as follows: a. the limited ligand amount of modifications; b. possible steric hindrance, which was likely to prevent ligand-receptor interaction during the delivery process. c. the restrained antigen saturation highly expressed on the cell membrane, will definitely decrease the specificity and often lead to "off-target" effects of NDDs; and d. water insolubility of nanocarriers due to excess of ligands modification. Obviously, any regulation of receptors on surface of tumor cells exerted an important influence on the delivery of targeting systems. Herein, receptor upregulation was mostly desired for enhancing targeted therapy from the cellular level. This technique with the amplification of receptors has the potential to enhance tumor sensitivity towards corresponding ligand-modified nanoparticles, and thereby increasing the effective therapeutic concentration as well as improving the efficacy of chemotherapy. The enhancement of positively expressed receptors on tumor cells and receptor-dependent therapeutic agents or NDDs with an assembled "self-promoting" effect contributes to increasing cell sensitivity to NPs, and will provide a basic platform for clinical therapeutic practice. In this review, we highlight the significance of modulating various receptors on different types of cancer cells for drug delivery and therapeutic benefits.

EGFR Targeted Cetuximab-Valine-Citrulline (vc)-Doxorubicin Immunoconjugates- Loaded Bovine Serum Albumin (BSA) Nanoparticles for Colorectal Tumor Therapy

Background

Specific modifications to carriers to achieve targeted delivery of chemotherapeutics into malignant tissues are a critical point for efficient diagnosis and therapy. In this case, bovine serum albumin (BSA) was conjugated with cetuximab–valine–citrulline (vc)–doxorubicin (DOX) to target epidermal growth factor receptor (EGFR) and enable the release of drug in EGFR-overexpressed tumor cells.

Methods

Maleimidocaproyl–valine–citrulline–p-aminobenzylcarbonyl-p-nitrophenol (MC-Val-Cit-PAB-PNP) and DOX were used to synthesize MC-Val-Cit-PAB-DOX, which was further linked with cetuximab to prepare antibody–drug conjugates (ADCs). Then, the ADCs were adsorbed to the surface of the BSA nanoparticles (NPs), which were prepared by a desolvation method to obtain cetuximab-vc-DOX-BSA-NPs. The cetuximab-vc-DOX conjugates adsorbed on the surface of the BSA nanoparticles were determined and optimized by size exclusion chromatography. An in vitro cytotoxicity study was conducted using a colon carcinoma cell line with different EGFR-expression levels to test the selectivity of cetuximab-vc-DOX-NPs.

Results

The vc-DOX and cetuximab-vc-DOX conjugates were both synthesized successfully and their structural characteristics confirmed by ¹H-NMR and SDS-PAGE. The MTT assay showed stronger cytotoxicity of cetuximab-vc-DOX-NPs versus control IgG-vc-DOX-NPs in EGFR–overexpressing RKO cells. Cellular binding and intracellular accumulation determined by flow cytometry and confocal laser scanning microscopy revealed the strong binding ability of cetuximab-vc-DOX-NPs to RKO cells. The in vivo imaging study demonstrated that cetuximab-vc-DOX-NPs exhibited higher fluorescent intensity in tumor tissues than non-decorated nanoparticles (IgG-vc-DOX-NPs). In vivo tumor inhibition and survival tests showed that cetuximab-vc-DOX-NPs revealed higher tumor inhibition efficacy and lower systemic toxicity than control IgG-vc-DOX- NPs

Conclusion

The obtained results emphasize that cetuximab-vc-DOX-NPs, with good tumor-targeting ability and low systemic toxicity, are a promising targeting system for drug delivery.

Measuring the concentration of protein nanoparticles synthesized by desolvation method: Comparison of Bradford assay, BCA assay, hydrolysis/UV spectroscopy and gravimetric analysis

The desolvation technique is one of the most popular methods for preparing protein nanoparticles for medicine, biotechnology, and food applications. We fabricated 11 batches of BSA nanoparticles and 2 batches of gelatin nanoparticles by desolvation method. BSA nanoparticles from 2 batches were cross-linked by heating at +70 °C for 2 h; other nanoparticles were stabilized by glutaraldehyde. We compared several analytical approaches to measuring their concentration: gravimetric analysis, bicinchoninic acid assay, Bradford assay, and alkaline hydrolysis combined with UV spectroscopy. We revealed that the cross-linking degree and method of cross-linking affect both Bradford and BCA assay. Direct measurement of protein concentration in the suspension of purified nanoparticles by dye-binding assays can lead to significant (up to 50-60%) underestimation of nanoparticle concentration. Quantification of non-desolvated protein (indirect method) is affected by the presence of small nanoparticles in supernatants and can be inaccurate when the yield of desolvation is low. The reaction of cross-linker with protein changes UV absorbance of the latter. Therefore pure protein solution is an inappropriate calibrator when applying UV spectroscopy for the determination of nanoparticle concentration. Our recommendation is to determine the concentration of protein nanoparticles by at least two different methods, including gravimetric analysis.

Peptides, proteins and nanotechnology: a promising synergy for breast cancer targeting and treatment

INTRODUCTION

The use of nanoparticles for breast cancer targeting and treatment has become a reality. They are safe and possess interesting peculiarities such as the unspecific accumulation into the tumor site and the possibility to activate controlled drug release as compared to free drugs. However, there are still many areas of improvement which can certainly be addressed with the use of peptide-based elements.

AREAS COVERED

The article reviews different preclinical strategies employing peptides and proteins in combination with nanoparticles for breast cancer targeting and treatment as well as peptide and protein-targeted encapsulated drugs, and it lists the current clinical status of therapies using peptides and proteins for breast cancer.

EXPERT OPINION

The conjugation of protein and peptides can improve tumor homing of nanoparticles, increase cellular penetration and attack specific drivers and vulnerabilities of the breast cancer cell to promote tumor cytotoxicity while reducing secondary effects in healthy tissues. Examples are the use of antibodies, arginylglycylaspartic acid (RGD) peptides, membrane disruptive peptides, interference peptides, and peptide vaccines. Although their implementation in the clinic has been relatively slow up to now, we anticipate great progress in the field which will translate into more efficacious and selective nanotherapies for breast cancer.

A review of nanotechnology-based approaches for breast cancer and triple-negative breast cancer

Breast cancer (BC) is one of the most prevalent cancers in women. Triple-negative breast cancer (TNBC) in which the three major receptors i.e. estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2), are absent is known to express the most aggressive phenotype and increased metastasis which results in the development of resistance to chemotherapy. It offers various therapeutic advantages in treating BC and TNBC. Nanotechnology offers various unique characteristics such as small size (nanometric), active and passive targeting, and the ability to attach multiple targeting moieties, controlled release, and site-specific targeting. This review focuses on conventional drug therapies, recent treatment strategies, and unique therapeutic approaches available for BC and TNBC. The role of breast cancer stem cells in the recurrence of BC and TNBC has also been highlighted. Several chemotherapeutic agents delivered using nanocarriers such as polymeric nanoparticles/micelles, metallic/inorganic NPs, and lipid-based NPs (Liposome, solid-lipid nanoparticles (SLNs), and nanostructured lipid carriers (NLCs)), etc. with excellent responses in the treatment of BC/TNBC along with breast cancer stem cells have been discussed in details. Moreover, the application of nanomedicine including CRISPR nanoparticle, exosomes for the treatment of BC/TNBC and other molecular targets available such as poly (ADP-ribose) polymerase (PARP), epidermal growth factor receptor (EGFR), Vascular endothelial growth factor (VEGF), etc. for further exploration have also been discussed.

Engineering peptide-targeted liposomal nanoparticles optimized for improved selectivity for HER2-positive breast cancer cells to achieve enhanced in vivo efficacy

Here, we report rationally engineered peptide-targeted liposomal doxorubicin nanoparticles that have an enhanced selectivity for HER2-positive breast tumor cells with high purity, reproducibility, and precision in controlling stoichiometry of targeting peptides. To increase HER2-positive tumor cell selective drug delivery, we optimized the two most important design parameters, peptide density and linker length, via systematic evaluations of their effects on both in vitro cellular uptake and in vivo tumor accumulation and cellular uptake. The optimally designed nanoparticles were finally evaluated for their tumor inhibition efficacy using in vivo MMTV-neu transplantation mouse model. In vitro, we demonstrated that ~1% peptide density and EG8 linker were optimal parameters for targeted nanoparticle formulations to enhance HER2-positive cancer cellular uptake while preventing non-selectivity. In vivo results demonstrated that at 0.5% peptide density, enhancement of tumor cell uptake over non-targeted nanoparticles was ~2.7 fold and ~3.4 fold higher for targeted nanoparticles with EG8 and EG18 linker, respectively, while their accumulation levels at tumor tissue were similar to the non-targeted nanoparticles. These results were consistent with in vivo efficacy outcomes that ~90% tumor growth inhibition was achieved by Dox-loaded HER2 receptor targeted nanoparticles, TNP^HER2pep, over control while all nanoparticle formulations minimized overall systemic toxicity relative to free Dox. This study highlights the significance of understanding and optimizing the effects of liposomal nanoparticle design parameters for enhancement of tumor selectivity to achieve improved in vivo therapeutic outcomes.

Drug uptake-based chemoresistance in breast cancer treatment

Breast cancer is the most prevalent type of tumor and the second leading cause of death due to cancer among women. Although screening methods, diagnosis and therapeutic options have improved in the last decade, chemoresistance remains an important challenge. There is evidence relating breast cancer resistance with signaling pathways involving hormone and growth receptors, survival, apoptosis and the activation of efflux pumps. However, the resistance mechanisms linked to drug uptake are poorly understood, despite it often being observed that the drug content is lower in resistant cancer cells and that the entry of the drug into these cells is a limiting process for the subsequent therapeutic effect.In this review, we provide an overview of drug uptake-based resistance mechanisms developed by cancer cells in the four main types of chemotherapy used in breast cancer: anthracyclines, taxanes, oxazaphosphorines and platinum-based drugs. The contribution of tumor microenvironment to reduced drug-uptake and multidrug resistance is also analyzed. As a developing field, nanomedicine-based approaches provide promising opportunities to improve drug specific targeting, cell interaction and uptake into cancer cells. The endocytic-mediated pathways attributed to the different types of nanoformulations as well as the contribution of nanotherapeutics to overcoming chemoresistance affecting drug uptake in breast cancer will be described. New approaches focusing on drug uptake mechanisms could improve breast cancer chemotherapy, obtaining better dose-response outcomes and reducing toxic side effects.

Albumin nanoscience: homing nanotechnology enabling targeted drug delivery and therapy

Albumin is a biocompatible, non-immunogenic and versatile drug carrier system. It has been widely used to extend the half-life, enhance stability, provide protection from degradation and allow specific targeting of therapeutic agents to various disease states. Understanding the role of albumin as a drug delivery and distribution system has increased remarkably in the recent years from the development of albumin-binding prodrugs to albumin as a drug carrier system. The extraordinary surface property of albumin makes it possible to bind various endogenous and exogenous molecules. This review succinctly deals with several albumin-drug conjugates and nanoparticles along with their preparation techniques and focuses on surface-modified albumin and targeting of albumin formulation to specific organs and tissues. It also summarizes research efforts on albumin nanoparticles used for delivering drugs to tumor cells and describes their role in permeation through tumor vasculature and in receptor mediated endocytosis, which is also described in this review. The versatility of albumin and ease of preparation makes it a suitable drug carrier system, swhich is the major objective of this review.

Perlecan-targeted nanoparticles for drug delivery to triple-negative breast cancer

Aim:

We previously developed two antibodies that bind to a cell surface protein, perlecan, overexpressed in triple-negative breast cancer (TNBC). The goal of this study was to investigate these antibodies as targeting ligands for nanoparticle-mediated drug delivery.

Methods:

Paclitaxel-loaded poly(D,L-lactide-co-glycolide) nanoparticles were functionalized with antibodies using thiol–maleimide chemistry. Effect of antibody functionalization on therapeutic efficacy of drug-loaded nanoparticles was investigated using in vitro and in vivo models of TNBC.

Results:

The antibodies were covalently conjugated to nanoparticles without affecting antibody binding affinity or nanoparticle properties. Perlecan-targeted nanoparticles showed improved cell uptake, retention, cytotoxicity in vitro and enhanced tumor growth inhibition in vivo.

Conclusion:

The data presented here indicates that perlecan-targeted nanoparticles can improve tumor drug delivery to TNBC.

Natural biodegradable polymers based nano-formulations for drug delivery: A review

Nanomedicines are now considered as the new-generation medication in the current era mainly because of their features related to nano size. The efficacy of many drugs in their micro/macro formulations is shown to have poor bioavailability and pharmacokinetics after oral administration. To overcome this predicament, use of natural/synthetic biodegradable polymeric nanoparticles (NPs) have gained prominence in the field of nanomedicine for targeted drug delivery to improve biocompatibility, bioavailability, safety, enhanced permeability, better retention time and lower toxicity. For drug delivery, it is essential to have biodegradable nanoparticle formulations for safe and efficient transport and release of drug at the intended site. Moreover, depending on the target organ, a suitable biodegradable polymer can be selected as the drug-carrier for target specific as well as for sustained drug delivery. The aim of this review is to present the current status and scope of natural biodegradable polymers as well as some emerging polymers with special characteristics as suitable carriers for drug delivery applications. The most widely preferred preparation methods are discussed along with their characterization using different analytical techniques. Further, the review highlights significant features of methods developed using natural polymers for drug entrapment and release studies.

Specific drug delivery efficiently induced human breast tumor regression using a lipoplex by non-covalent association with anti-tumor antibodies

Background

A cationic liposome-PEG-PEI complex (LPPC) was employed as a carrier for achieving targeted delivery of drug to human epidermal growth factor receptor-2 (HER2/neu)-expressing breast cancer cells. LPPC can be easily loaded with an anti-tumor drug and non-covalently associated with an anti-tumor antibody such as Herceptin that is clinically used to rapidly form immunoparticles within 1 h.

Results

Drug-loaded LPPC have an average size about 250 nm and a zeta potential of about 40 mV. Herceptin was complexed onto surface of the LPPC to form the drug/LPPC/Herceptin complexes. The size of curcumin/LPPC/Herceptin complexes were 280 nm and the zeta potentials were about 23 mV. Targeting ability of this delivery system was demonstrated through specific binding on surface of cells and IVIS images in vivo, which showed specific binding in HER2-positive SKBR3 cells as compared to HER2-negative Hs578T cells. Only the drug/LPPC/Herceptin complexes displayed dramatically increased the cytotoxic activity in cancer cells. Both in vitro and in vivo results indicated that Herceptin adsorbed on LPPC directed the immunocomplex towards HER2/neu-positive cells but not HER2/neu-negative cells. The complexes with either component (curcumin or doxorubicin) used in the LPPC-delivery system provided a better therapeutic efficacy compared to the drug treatment alone and other treatment groups, including clinical dosages of Herceptin and LipoDox, in a xenografted model.

Conclusions

LPPC displays important clinical implications by easily introducing a specific targeting characteristic to drugs utilized for breast cancer therapy.

Electronic supplementary material

The online version of this article (10.1186/s12951-019-0457-3) contains supplementary material, which is available to authorized users.

Advances in Receptor-Mediated, Tumor-Targeted Drug Delivery

Receptor-mediated drug delivery presents an opportunity to enhance therapeutic efficiency by accumulating drug within the tissue of interest and reducing undesired, off-target effects. In cancer, receptor overexpression is a platform for binding and inhibiting pathways that shape biodistribution, toxicity, cell binding and uptake, and therapeutic function. This review will identify tumor-targeted drug delivery vehicles and receptors that show promise for clinical translation based on quantitative in vitro and in vivo data. The authors describe the rationale to engineer a targeted drug delivery vehicle based on the ligand, chemical conjugation method, and type of drug delivery vehicle. Recent advances in multivalent targeting and ligand organization on tumor accumulation are discussed. Revolutionizing receptor-mediated drug delivery may be leveraged in the therapeutic delivery of chemotherapy, gene editing tools, and epigenetic drugs.

Harnessing albumin as a carrier for cancer therapies

Serum albumin, a natural ligand carrier that is highly concentrated and long-circulating in the blood, has shown remarkable promise as a carrier for anti-cancer agents. Albumin is able to prolong the circulation half-life of otherwise rapidly cleared drugs and, importantly, promote their accumulation within tumors. The applications for using albumin as a cancer drug carrier are broad and include both traditional cancer chemotherapeutics and new classes of biologics. Strategies for leveraging albumin for drug delivery can be classified broadly into exogenous and in situ binding formulations that utilize covalent attachment, non-covalent association, or encapsulation in albumin-based nanoparticles. These methods have shown remarkable preclinical and clinical successes that are examined in this review.

Optimization and comparison of CD4-targeting lipid-polymer hybrid nanoparticles using different binding ligands

Monoclonal antibodies and peptides are conjugated to the surface of nanocarriers (NCs) for targeting purposes in numerous applications. However, targeting efficacy may vary with their specificity, affinity, or avidity when linked to NCs. The physicochemical properties of NCs may also affect targeting. We compared the targeting efficacy of the CD4 binding peptide BP4 and an anti-CD4 monoclonal antibody (CD4 mAb) and its fragments, when conjugated to lipid-coated poly(lactic-co-glycolic) acid nanoparticles (LCNPs). Negatively charged LCNPs with cholesteryl butyrate in the lipid layer (cbLCNPs) dramatically reduced nonspecific binding, leading to higher targeting specificity, compared to neutral or positively charged LCNPs with DOTAP (dtLCNP). cbLCNPs surface conjugated with a CD4 antibody (CD4-cbLCNPs) or its fragments (fCD4-cbLCNPs), but not BP4, showed high binding in vitro to the human T cell line 174xCEM, and preferential binding to CD3+ CD14-CD8- cells from pigtail macaque peripheral blood mononuclear cells. CD4-cbLCNPs showed 10-fold higher binding specificity for CD4+ than CD8+ T cells, while fCD4-cbLCNPs demonstrated the highest binding level overall, but only three-fold higher binding specificity. This study demonstrates the importance of ζ-potential on NC targeting and indicates that CD4 mAb and its fragments are the best candidates for delivery of therapeutic agents to CD4+ T cells. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1177-1188, 2018.

The use of nanoparticulates to treat breast cancer

Breast cancer is a major ongoing public health issue among women in both developing and developed countries. Significant progress has been made to improve the breast cancer treatment in the past decades. However, the current clinical approaches are invasive, of low specificity and can generate severe side effects. As a rapidly developing field, nanotechnology brings promising opportunities to human cancer diagnosis and treatment. The use of nanoparticulate-based platforms overcomes biological barriers and allows prolonged blood circulation time, simultaneous tumor targeting and enhanced accumulation of drugs in tumors. Currently available and clinically applicable innovative nanoparticulate-based systems for breast cancer nanotherapies are discussed in this review.

Impact of albumin based approaches in nanomedicine: Imaging, targeting and drug delivery

A major challenge in the field of nanomedicine is to transform laboratory innovations into commercially successful clinical products. In this campaign, a variety of nanoenabled approaches have been designed and investigated for their role in biomedical applications. The advantages associated with the unique structure of albumin imparts it with the ability to interact with variety of molecules, while the functional groups present on their surface provide base for large number of modifications making it as an ideal nanocarrier system. So far, a variety of albumin based nanoenabled approaches have been intensively exploited for effective diagnosis and personalized medicine, among them some have successfully completed their journey from lab bench to marketed products. This review focuses on the recent most promising advancement in the field of albumin based nanoenabled approaches for various biomedical applications and their potential use in cancer diagnosis and therapy.

Conserved effects and altered trafficking of Cetuximab antibodies conjugated to gold nanoparticles with precise control of their number and orientation

Gold nanoparticles (17 nm) have been functionalized with the antiangiogenic monoclonal antibody drug Cetuximab at a well-defined orientation and coverage density of antibodies. Functionalization has been carried out through site-directed chemistry via the selective oxidation of the carbohydrate moiety of antibodies linked to a thiolated hydrazide. A431 tumor cells have been exposed to these conjugates for in vitro evaluation of their effects. In addition to epithelial growth factor receptor blocking, trafficking and signaling alterations were also observed. Thus, the blocking effects of Cetuximab were increased and sustained for a longer time when associated with the nanoparticles. Enhancing antibody therapy effects by decreasing the needed dose and prolonging its effect by avoiding receptor recycling may serve to obtain increased therapeutic benefits for immunotherapy.

Therapeutic use of monoclonal antibodies: general aspects and challenges for drug delivery

Monoclonal antibodies are routinely used in several fields but the great challenge has been their use as therapeutic agents for the treatment of diseases, such as breast cancer, leukemia, asthma, macular degeneration, arthritis, Crohn’s disease, and transplants, among others.

Monoclonal antibodies are protein molecules made in the laboratory from hybridoma cells by recombinant DNA technology.

Important advances have been made over the past decade to improve some critical points, such as safety and efficacy of the first generation of therapeutic antibodies.

This type of molecules presents a significant challenge from the pharmaceutical point of view due to their characteristics, such as molecular size, stability, and solubility. In this chapter we have attempted to identify the major issues associated with therapeutic approaches, formulating drawbacks and delivering antibody drugs, particularly focused on the challenges and opportunities that these present for the future.

Albumin nanostructures as advanced drug delivery systems

INTRODUCTION

One of the biggest impacts that the nanotechnology has made on medicine and biology, has been in the area of drug delivery systems (DDSs). Many drugs suffer from serious problems concerning insolubility, instability in biological environments, poor uptake into cells and tissues, sub-optimal selectivity for targets and unwanted side effects. Nanocarriers can be designed as DDSs to overcome many of these drawbacks. One of the most versatile building blocks to prepare these nanocarriers is the ubiquitous, readily available and inexpensive protein, serum albumin. Areas covered: This review covers the use of different types of albumin (human, bovine, rat, and chicken egg) to prepare nanoparticle and microparticle-based structures to bind drugs. Various methods have been used to modify the albumin structure. A range of targeting ligands can be attached to the albumin that can be recognized by specific cell receptors that are expressed on target cells or tissues. Expert opinion: The particular advantages of albumin used in DDSs include ready availability, ease of chemical modification, good biocompatibility, and low immunogenicity. The regulatory approvals that have been received for several albumin-based therapeutic agents suggest that this approach will continue to be successfully explored.

Functionalized immunostimulating complexes with protein A via lipid vinyl sulfones to deliver cancer drugs to trastuzumab-resistant HER2-overexpressing breast cancer cells

Background

Around 20%–30% of breast cancers overexpress the proto-oncogene human epidermal growth receptor 2 (HER2), and they are characterized by being very invasive. Therefore, many current studies are focused on testing new therapies against tumors that overexpress this receptor. In particular, there exists major interest in new strategies to fight breast cancer resistant to trastuzumab (Tmab), a humanized antibody that binds specifically to HER2 interfering with its mitogenic signaling. Our team has previously developed immunostimulating complexes (ISCOMs) as nanocapsules functionalized with lipid vinyl sulfones, which can incorporate protein A and bind to G immunoglobulins that makes them very flexible nanocarriers.

Methods and results

The aim of this in vitro study was to synthesize and evaluate a drug delivery system based on protein A-functionalized ISCOMs to target HER2-overexpressing cells. We describe the preparation of ISCOMs, the loading with the drugs doxorubicin and paclitaxel, the binding of ISCOMs to alkyl vinyl sulfone-protein A, the coupling of Tmab, and the evaluation in both HER2-overexpressing breast cancer cells (HCC1954) and non-overexpressing cells (MCF-7) by flow cytometry and fluorescence microscopy. Results show that the uptake is dependent on the level of overexpression of HER2, and the analysis of the cell viability reveals that targeted drugs are selective toward HCC1954, whereas MCF-7 cells remain unaffected.

Conclusion

Protein A-functionalized ISCOMs are versatile carriers that can be coupled to antibodies that act as targeting agents to deliver drugs. When coupling to Tmab and loading with paclitaxel or doxorubicin, they become efficient vehicles for the selective delivery of the drug to Tmab-resistant HER2-overexpressing breast cancer cells. These nanoparticles may pave the way for the development of novel therapies for poor prognosis resistant patients.

Functionalized magnetic dextran-spermine nanocarriers for targeted delivery of doxorubicin to breast cancer cells

In recent decades, targeted drug delivery systems for breast cancer treatment emerged as an ideal alternative and promising solution to reduce systemic side effects of chemotherapeutic agents. In this study, the preparation and characterization of cationic doxorubicin (DOX) loaded magnetic dextran-spermine (DEX-SP) nanocarriers (DEX-SP-DOX) by ionic gelation were fully investigated. Then, anti-HER2 as a monoclonal antibody (mAb) and targeting ligand was conjugated via EDC/NHS reagents. The binding was confirmed by Bradford assay and further assessments were carried out by size and zeta potential measurements. Cytotoxicity effect and internalization of magnetic nanocarriers were assessed by MTT and Prussian blue assays and transmission electron microscopy (TEM), respectively. DLS measurements indicated that the size of nanocarriers increased from 62 to 84 nm by conjugation of anti-HER2 to them. The in vitro release of DOX from mAb conjugated magnetic nanocarriers at pHs 5 and 7.4 was found to be 85 and 55.5%, respectively. The MTT and Prussian blue assays demonstrated enhanced and selective uptake of DEX-SP-DOX-mAb by SKBR cell (HER2 overexpressed cells) in comparison with unconjugated nanocarriers due to higher cellular binding. The TEM result also confirmed cellular internalization of DEX-SP-DOX-mAb magnetic nanocarriers. These results are very promising for targeted delivery of DOX to HER2 positive breast cancer cells.

CXCR-4 Targeted, Short Wave Infrared (SWIR) Emitting Nanoprobes for Enhanced Deep Tissue Imaging and Micrometastatic Cancer Lesion Detection

Realizing the promise of precision medicine in cancer therapy depends on identifying and tracking cancerous growths to maximize treatment options and improve patient outcomes. This goal of early detection remains unfulfilled by current clinical imaging techniques that fail to detect lesions due to their small size and suborgan localization. With proper probes, optical imaging techniques can overcome this by identifying the molecular phenotype of tumors at both macroscopic and microscopic scales. In this study, the first use of nanophotonic short wave infrared technology is proposed to molecularly phenotype small lesions for more sensitive detection. Here, human serum albumin encapsulated rare-earth nanoparticles (ReANCs) with ligands for targeted lesion imaging are designed. AMD3100, an antagonist to CXCR4 (a classic marker of cancer metastasis) is adsorbed onto ReANCs to form functionalized ReANCs (fReANCs). fReANCs are able to preferentially accumulate in receptor positive lesions when injected intraperitoneally in a subcutaneous tumor model. fReANCs can also target subtissue microlesions at a maximum depth of 10.5 mm in a lung metastatic model of breast cancer. Internal lesions identified with fReANCs are 2.25 times smaller than those detected with ReANCs. Thus, an integrated nanoprobe detection platform is presented, which allows target-specific identification of subtissue cancerous lesions.

The study on the preparation and characterization of gene-loaded immunomagnetic albumin nanospheres and their anti-cell proliferative effect combined with magnetic fluid hyperthermia on GLC-82 cells

As one of the most common malignant tumors, the clinical and socio-economic consequences of lung cancer are significant. Currently, surgery is the main treatment strategy for this disease, but the survival rates of lung cancer patients are not ideal due to the high recurrence rate of the disease. Therefore, many researchers are exploring new specific therapeutic methods that are highly curative and minimally cytotoxic to healthy tissues. To this end, albumin nanospheres simultaneously were loaded with super-paramagnetic iron oxide nanoparticles (as gene vector and anticancer gene), and plasmid pDONR223-IFNG, and modified with anti-EGFR monoclonal antibody cetuximab as therapy. Targeting agents, namely gene-loaded immunomagnetic albumin nanospheres (cetuximab [C225]-IFNG-IMANS), were prepared for targeted lung carcinoma cells (GLC-82 cell lines). Transmission electron microscopy images showed that the C225-IFNG-IMANS were successfully prepared, and the ability of the nanospheres to target GLC-82 cells in vitro was confirmed by Prussian blue staining, immunofluorescence experiments, and magnetic resonance imaging. Transfection photographs and agarose gel electrophoresis proved that pDONR223-IFNG could be encased in the albumin nanospheres. A Cell Counting Kit-8 assay showed that the combination therapy group had significantly more therapeutic effects on GLC-82 cells than other therapy groups. A flow cytometry assay showed that the apoptotic index of the combined treatment group was 67.68%, whereas the indices of the C225 group, gene therapy group, and magnetic fluid hyperthermia group were 12.2%, 16.34%, and 20.04% respectively. Therefore, the combination of thermal treatment, molecular targeted treatment, and gene treatment synergistically targets GLC-82 cells, and the use of C225-IFNG-IMANS as a gene or drug carrier offers a novel and promising approach for the treatment of lung cancer.

Magnetic albumin immuno-nanospheres as an efficient gene delivery system for a potential use in lung cancer: preparation, in vitro targeting and biological effect analysis

Magnetic albumin immuno-nanospheres (MAINs), simultaneously loaded with super-paramagnetic iron oxide nanoparticles for targeting application and anticancer gene, plasmid-survivin/shRNA (pshRNA) and modified with anti-EGFR monoclonal antibody Cetuximab for targeting and treatment agents, were prepared for targeting lung cancer. Transmission electron microscopy images and transfection photographs, respectively, showed that magnetic nanoparticles and pshRNA were successfully encased in the albumin nanospheres. The release profiles in vitro indicated that nanospheres had an obvious effect of sustained release of pshRNA. The results of slide agglutination test and immunofluorescence analysis demonstrated that the immuno-nanospheres retained the immuno-reactivity of Cetuximab. The MAINs significantly increased adherence and uptake by GLC-82 lung cancer cells over-expressed epidermal growth factor receptor over a magnetic albumin nanospheres (MANs) control. The pshRNA-loaded MAINs formulation was more effective than equimolar doses of free Cetuximab, single magnetic targeting with pshRNA (pshRNA-loaded MANs) or single monoclonal antibody targeting with pshRNA (pshRNA-loaded AINs) in the treatment of GLC-82 lung cancer cells. Collectively, the study indicates that the novel pshRNA-loaded magnetic immuno-nanospheres represent a promising approach for magnetic and monoclonal antibody-dependent gene targeting in lung cancer therapy.

PEGylated human serum albumin (HSA) nanoparticles: preparation, characterization and quantification of the PEGylation extent

Modification with poly(ethylene glycol) (PEG) is a widely used method for the prolongation of plasma half-life of colloidal carrier systems such as nanoparticles prepared from human serum albumin (HSA). However, the quantification of the PEGylation extent is still challenging. Moreover, the influence of different PEG derivatives, which are commonly used for nanoparticle conjugation, has not been investigated so far. The objective of the present study is to develop a method for the quantification of PEG and to monitor the influence of diverse PEG reagents on the amount of PEG linked to the surface of HSA nanoparticles. A size exclusion chromatography method with refractive index detection was established which enabled the quantification of unreacted PEG in the supernatant. The achieved results were confirmed using a fluorescent PEG derivative, which was detected by photometry and fluorimetry. Additionally, PEGylated HSA nanoparticles were enzymatically digested and the linked amount of fluorescently active PEG was directly determined. All the analytical methods confirmed that under optimized PEGylation conditions a PEGylation efficiency of up to 0.5 mg PEG per mg nanoparticle could be achieved. Model calculations made a 'brush' conformation of the PEG chains on the particle surface very likely. By incubating the nanoparticles with fetal bovine serum the reduced adsorption of serum proteins on PEGylated HSA nanoparticles compared to non-PEGylated HSA nanoparticles was demonstrated using sodium dodecylsulfate polyacrylamide gel electrophoresis. Finally, the positive effect of PEGylation on plasma half-life was demonstrated in an in vivo study in mice. Compared to unmodified nanoparticles the PEGylation led to a four times larger plasma half-life.

Hybrid paclitaxel and gold nanorod-loaded human serum albumin nanoparticles for simultaneous chemotherapeutic and photothermal therapy on 4T1 breast cancer cells

The use of human serum albumin nanoparticles (HSAPs) as a drug carrier system for cancer treatment has proven successful through current marketable clinical formulations. Despite this success, there is a current lack of multifunctional HSAPs, which offer combinational therapies of more than one proven technique. Gold nanorods (AuNRs) have also shown medicinal promise due to their photothermal therapy capabilities. In this study, a desolvation and cross-linking approach was employed to successfully encapsulate gold nanorods into HSAPs simultaneously with the chemotherapeutic drug paclitaxel (PAC); forming PAC-AuNR-HSAPs with desirable overall particle sizes of 299 ± 6 nm. The loading efficiency of paclitaxel into PAC-AuNR-HSAPs reached up to 3 μg PAC/mg HSA. The PAC-AuNR-HSAPs experienced photothermal heating; with the bulk particle solution reaching up to 46 °C after 15 min of near-IR laser exposure. This heat increase marked the successful attainment of the temperature necessary to cause severe cellular hyperthermia and necrosis. The encasement strategy facilitated a colloidal hybrid treatment system capable of enhanced permeability and retention effects, photothermal ablation of cancer cells, and release of the active paclitaxel of up to 188 ng (from PAC-AuNR-HSAPs created with 30 mg HSA) in a single 15 min irradiation session. When treated with PAC-AuNR-HSAPs containing 20 μg PAC/mL particle solution, 4T1 mouse breast cancer cells experienced ∼82% cell death without irradiation and ∼94% cell death after just one irradiation session. The results for PAC-AuNR-HSAPs were better than that of free PAC, which only killed ∼77% of the cells without irradiation and ∼80% with irradiation. The hybrid particle system also lends itself to future customizable external functionalities via conjugated targeting ligands, such as antibodies. Internal entrapment of patient tailored medication combinations are also possible with this combination treatment platform, which may result in improved quality of life for those undergoing treatment.

Nanoparticle targeting of anti-cancer drugs that alter intracellular signaling or influence the tumor microenvironment

Nanoparticle-based therapeutics are poised to become a leading delivery strategy for cancer treatment because they potentially offer higher selectivity, reduced toxicity, longer clearance times, and increased efficacy compared to conventional systemic therapeutic approaches. This article reviews existing nanoparticle technologies and methods that are used to target drugs to treat cancer by altering signal transduction or modulating the tumor microenvironment. We also consider the implications of recent advances in the nanotherapeutics field for the future of cancer therapy.

Nanoencapsulation of ultra-small superparamagnetic particles of iron oxide into human serum albumin nanoparticles

Human serum albumin nanoparticles have been utilized as drug delivery systems for a variety of medical applications. Since ultra-small superparamagnetic particles of iron oxide (USPIO) are used as contrast agents in magnetic resonance imaging, their encapsulation into the protein matrix enables the synthesis of diagnostic and theranostic agents by surface modification and co-encapsulation of active pharmaceutical ingredients. The present investigation deals with the surface modification and nanoencapsulation of USPIO into an albumin matrix by using ethanolic desolvation. Particles of narrow size distribution and with a defined particle structure have been achieved.