Antibody engineering promotes nanomedicine for cancer treatment

Lipid-core nanoparticles: Classification, preparation methods, routes of administration and recent advances in cancer treatment

Nanotechnological drug delivery platforms represent a new paradigm for cancer therapeutics as they improve the pharmacokinetic profile and distribution of chemotherapeutic agents over conventional formulations. Among nanoparticles, lipid-based nanoplatforms possessing a lipid core, that is, lipid-core nanoparticles (LCNPs), have gained increasing interest due to lipid properties such as high solubilizing potential, versatility, biocompatibility, and biodegradability. However, due to the wide spectrum of morphologies and types of LCNPs, there is a lack of consensus regarding their terminology and classification. According to the current state-of-the-art in this critical review, LCNPs are defined and classified based on the state of their lipidic components in liquid lipid nanoparticles (LLNs). These include lipid nanoemulsions (LNEs) and lipid nanocapsules (LNCs), solid lipid nanoparticles (SLNs) and nanostructured lipid nanocarriers (NLCs). In addition, we present a comprehensive and comparative description of the methods employed for their preparation, routes of administration and the fundamental role of physicochemical properties of LCNPs for efficient antitumoral drug-delivery application. Market available LCNPs, clinical trials and preclinical in vivo studies of promising LCNPs as potential treatments for different cancer pathologies are summarized.

EGFR-Targeted Cellular Delivery of Therapeutic Nucleic Acids Mediated by Boron Clusters

New boron carriers with high boron content and targeted cancer-cell delivery are considered the first choice for boron neutron capture therapy (BNCT) for cancer treatment. Previously, we have shown that composites of antisense oligonucleotide and boron clusters are functional nanoparticles for the downregulation of expression of epidermal growth factor receptor (EGFR) and can be loaded into EGFR-overexpressing cancer cells without a transfection factor. In this study, we hypothesize that free cellular uptake is mediated by binding and activation of the EGFR by boron clusters. Proteomic analysis of proteins pulled-down from various EGFR-overexpressing cancer cells using short oligonucleotide probes, conjugated to 1,2-dicarba-closo-dodecaborane (1,2-DCDDB, [C₂B₁₀H₁₂]) and [(3,3'-Iron-1,2,1',2'-dicarbollide)^-] (FESAN, [Fe(C₂B₉H₁₁)₂]^-), evidenced that boron cage binds to EGFR subdomains. Moreover, inductively coupled plasma mass spectrometry (ICP MS) and fluorescence microscopy analyses confirmed that FESANs-highly decorated B-ASOs were efficiently delivered and internalized by EGFR-overexpressing cells. Antisense reduction of EGFR in A431 and U87-MG cells resulted in decreased boron accumulation compared to control cells, indicating that cellular uptake of B-ASOs is related to EGFR-dependent internalization. The data obtained suggest that EGFR-mediated cellular uptake of B-ASO represents a novel strategy for cellular delivery of therapeutic nucleic acids (and possibly other medicines) conjugated to boron clusters.

[Targeted killing of CD133+ lung cancer stem cells using paclitaxel-loaded PLGA-PEG nanoparticles with CD133 aptamers]

OBJECTIVE

To construct a polylactic acid-glycolic acid-polyethylene glycol (PLGA-PEG) nanocarrier (N-Pac-CD133) coupled with a CD133 nucleic acid aptamer carrying paclitaxel for eliminating lung cancer stem cells (CSCs).

METHODS

Paclitaxel-loaded N-Pac-CD133 was prepared using the emulsion/solvent evaporation method and characterized. CD133⁺ lung CSCs were separated by magnetic bead separation and identified for their biological behaviors and gene expression profile. The efficiency of paclitaxel-loaded N-Pac-CD133 for targeted killing of lung cancer cells was assessed in vitro. SCID mice were inoculated with A549 cells and received injections of normal saline, empty nanocarrier linked with CD133 aptamer (N-CD133), paclitaxel, paclitaxel-loaded nanocarrier (N-Pac) or paclitaxel-loaded N-Pac-CD133 (n=8, 5 mg/kg paclitaxel) on days 10, 15 and 20, and the tumor weight and body weight of the mice were measured on day 40.

RESULTS

Paclitaxel-loaded N-Pac-CD133 showed a particle size of about 100 nm with a high encapsulation efficiency (>80%) and drug loading rate (>8%), and was capable of sustained drug release within 48 h. The CD133⁺ cell population in lung cancer cells showed the characteristic features of lung CSCs, including faster growth rate (30 days, P=0.001) and high expressions of tumor stem cell markers OV6(P < 0.001), CD133 (P=0.001), OCT3/4 (P=0.002), EpCAM (P=0.04), NANOG (P=0.005) and CD44 (P=0.02). Compared with N-Pac and free paclitaxel, paclitaxel-loaded N-Pac-CD133 showed significantly enhanced targeting ability and cytotoxicity against lung CSCs in vitro (P < 0.001) and significantly reduced the formation of tumor spheres (P < 0.001). In the tumor-bearing mice, paclitaxel-loaded N-Pac-CD133 showed the strongest effects in reducing the tumor mass among all the treatments (P < 0.001).

CONCLUSION

CD133 aptamer can promote targeted delivery of paclitaxel to allow targeted killing of CD133⁺ lung CSCs. N-Pac-CD133 loaded with paclitaxel may provide an effective treatment for lung cancer by targeting the lung cancer stem cells.

Recent development for biomedical applications of magnetic nanoparticles

In recent decades, the use of engineered nanoparticles has been increasing in various sectors, including biomedicine, diagnosis, water treatment, and environmental remediation leading to significant public concerns. Among these nanoparticles, magnetic nanoparticles (MNPs) have gained many attentions in medicine, pharmacology, drug delivery system, molecular imaging, and bio-sensing due to their various properties. In addition, various studies have reviewed MNPs main applications in the biomedical engineering area with intense progress and recent achievements. Nanoparticles, especially the magnetic nanoparticles, have recently been confirmed with excellent antiviral activity against different viruses, including SARS-CoV-2(Covid-19) and their recent development against Covid-19 also has also been discussed. This review aims to highlight the recent development of the magnetic nanoparticles and their biomedical applications such as diagnosis of diseases, molecular imaging, hyperthermia, bio-sensing, gene therapy, drug delivery and the diagnosis of Covid-19.

Were magnetic materials useful in cancer therapy?

Cancer is one of the major challenges fronting the biomedical basic researches in our time. The study and development of effective therapeutic strategies for cancer therapy are vital. Among the many probable core constituents of nanoparticles, magnetite-based nanoparticles have been widely studied for cancer therapy owing to their inherent magnetic features, multifunctional design, biodegradable and biocompatible properties. Magnetic nanoparticles have been also designed for utilizing as contrast enhancer agents for magnetic resonance imaging, drug delivery systems, and most recently as a therapeutic element in inducing cellular death in tumor ablation therapies. This review aimed to provide an overview of the various applications of magnetic nanoparticles and recent achievements in developing these advanced materials for cancer therapy.

Controlled anti-cancer drug release through advanced nano-drug delivery systems: Static and dynamic targeting strategies

Advances in nanomedicine, including early cancer detection, targeted drug delivery, and personalized approaches to cancer treatment are on the rise. For example, targeted drug delivery systems can improve intracellular delivery because of their multifunctionality. Novel endogenous-based and exogenous-based stimulus-responsive drug delivery systems have been proposed to prevent the cancer progression with proper drug delivery. To control effective dose loading and sustained release, targeted permeability and individual variability can now be described in more-complex ways, such as by combining internal and external stimuli. Despite these advances in release control, certain challenges remain and are identified in this research, which emphasizes the control of drug release and applications of nanoparticle-based drug delivery systems. Using a multiscale and multidisciplinary approach, this study investigates and analyzes drug delivery and release strategies in the nanoparticle-based treatment of cancer, both mathematically and clinically.

Fatty Acid Synthase (FASN) siRNA-Encapsulated-Her-2 Targeted Fab'-Immunoliposomes for Gene Silencing in Breast Cancer Cells

Purpose

The overexpression of Her-2 in 25–30% breast cancer cases and the crosstalk between Her-2 and fatty acid synthase (FASN) establishes Her-2 as a promising target for site-directed delivery. The present study aimed to develop the novel lipid base formulations to target and inhibit the cellular proliferation of Her-2-expressing breast cancer cells through the silencing of FASN. In order to achieve this goal, we prepared DSPC/Chol and DOPE/CHEMS immunoliposomes, conjugated with the anti-Her-2 fab’ and encapsulated FASN siRNA against breast cancer cells.

Methods

We evaluated the size, stability, cellular uptake and internalization of various formulations of liposomes. The antiproliferative gene silencing potential was investigated by the cell cytotoxicity, crystal violet, wound healing and Western blot analyses in Her-2⁺ and Her-2^¯ breast cancer cells.

Results

The data revealed that both nanosized FASN-siRNA-encapsulated liposomes showed significantly higher cellular uptake and internalization with enhanced stability. The cell viability of Her-2⁺ SK-BR3 cells treated with the targeted formulation of DSPC/Chol- and DOPE/CHEMS-encapsulating FASN-siRNA reduced to 30% and 20%, respectively, whereas it was found to be 45% and 36% in MCF-7 cells. The wounds were not only failed to close but they became broader in Her-2⁺ cells treated with targeted liposomes of siRNA. Consequently, the amount of FASN decreased by 80% in SK-BR3 cells treated with non-targeted liposomes and it was 30% and 60% in the MCF-7 cells treated with DSPC/Chol and DOPE/CHEMS liposomes, respectively.

Conclusion

In this study, we developed the formulation that targeted Her-2 for the suppression of FASN and, therefore, inhibited the proliferation of breast cancer cells.

Combination Chemotherapy of Lung Cancer - Co-Delivery of Docetaxel Prodrug and Cisplatin Using Aptamer-Decorated Lipid-Polymer Hybrid Nanoparticles

Purpose

Lung cancer is the leading cause of cancer mortality worldwide. Drug resistance is the major barrier for the treatment of non-small cell lung cancer (NSCLC). The aim of this research is to develop an aptamer-decorated hybrid nanoparticle for the co-delivery of docetaxel prodrug (DTXp) and cisplatin (DDP) and to treat lung cancer.

Materials and Methods

Aptamer-conjugated lipid–polymer ligands and redox-sensitive docetaxel prodrug were synthesized. DTXp and DDP were loaded into the lipid–polymer hybrid nanoparticles (LPHNs). The targeted efficiency of aptamer-decorated, DTXp and DDP co-encapsulated LPHNs (APT-DTXp/DDP-LPHNs) was determined by performing a cell uptake assay by flow cytometry-based analysis. In vivo biodistribution and anticancer efficiency of APT-DTXp/DDP-LPHNs were evaluated on NSCLC-bearing mice xenograft.

Results

APT-DTXp/DDP-LPHNs had a particle size of 213.5 ± 5.3 nm, with a zeta potential of 15.9 ± 1.9 mV. APT-DTXp/DDP-LPHNs exhibited a significantly enhanced cytotoxicity (drug concentration causing 50% inhibition was 0.71 ± 0.09 μg/mL), synergy antitumor effect (combination index was 0.62), and profound tumor inhibition ability (tumor inhibition ratio of 81.4%) compared with the non-aptamer-decorated LPHNs and single drug-loaded LPHNs.

Conclusion

Since the synergistic effect of the drugs was found in this system, it would have great potential to inhibit lung tumor cells and in vivo tumor growth.

Dual-targeting nanomicelles with CD133 and CD44 aptamers for enhanced delivery of gefitinib to two populations of lung cancer-initiating cells

Lung cancer is an aggressive type of cancer that is associated with a high mortality rate. Lung cancer-initiating cells are populations of self-renewing cancer cells with pluripotent differentiation ability. Cancers typically originate from multiple phenotypically distinct cancer-initiating cells. CD133 and CD44 are specific markers that maybe used to distinguish lung cancer-initiating cells. The ability to target a variety of subsets of cancer-initiating cells instead of targeting only one population of cancer initiating-cells has the potential to increase the cancer therapeutic efficacy. In the present study, CD133 and CD44 aptamer-conjugated nanomicelles loaded with gefitinib (CD133/CD44-NM-Gef) were developed to target CD133⁺ and CD44⁺ lung cancer-initiating cells. The therapeutic efficacy of CD133/CD44-NM-Gef against lung cancer-initiating cells was assessed by evaluating cell proliferation, tumorsphere formation and detection of CD44⁺ and CD133⁺ cells using flow cytometry. The results indicated that CD133/CD44-NM-Gef targeted CD133⁺ and CD44⁺ lung cancer-initiating cells and exhibited greater therapeutic efficacy against lung cancer-initiating cells than single-target and non-targeted nanomicelles, suggesting that CD133/CD44-NM-Gef represents a promising treatment for lung cancer by specifically targeting lung cancer-initiating cells. To the best of our knowledge, the present study was the first to report on drug delivery via nanomedicines targeted to multiple populations of cancer-initiating cells using aptamers. As cancer is typically derived from phenotypically distinct cancer-initiating cells, the nanomicelle-based multiple targeting strategy provided is promising for targeting multiple subsets of cancer-initiating cell within a tumor.

Current trends and challenges in cancer management and therapy using designer nanomaterials

Nanotechnology has the potential to circumvent several drawbacks of conventional therapeutic formulations. In fact, significant strides have been made towards the application of engineered nanomaterials for the treatment of cancer with high specificity, sensitivity and efficacy. Tailor-made nanomaterials functionalized with specific ligands can target cancer cells in a predictable manner and deliver encapsulated payloads effectively. Moreover, nanomaterials can also be designed for increased drug loading, improved half-life in the body, controlled release, and selective distribution by modifying their composition, size, morphology, and surface chemistry. To date, polymeric nanomaterials, metallic nanoparticles, carbon-based materials, liposomes, and dendrimers have been developed as smart drug delivery systems for cancer treatment, demonstrating enhanced pharmacokinetic and pharmacodynamic profiles over conventional formulations due to their nanoscale size and unique physicochemical characteristics. The data present in the literature suggest that nanotechnology will provide next-generation platforms for cancer management and anticancer therapy. Therefore, in this critical review, we summarize a range of nanomaterials which are currently being employed for anticancer therapies and discuss the fundamental role of their physicochemical properties in cancer management. We further elaborate on the topical progress made to date toward nanomaterial engineering for cancer therapy, including current strategies for drug targeting and release for efficient cancer administration. We also discuss issues of nanotoxicity, which is an often-neglected feature of nanotechnology. Finally, we attempt to summarize the current challenges in nanotherapeutics and provide an outlook on the future of this important field.

Click chemistry-mediated tumor-targeting of SN38-loaded nanoparticles using trastuzumab

For efficient drug delivery, we introduce a click-chemistry-mediated two-step tumor-targeting strategy for nanoparticles (NPs). We modified HER2-binding trastuzumab with trans-cyclooctene (TCO-Trb), and fabricated tetrazine-modified NPs containing the anticancer drug, SN38 (SN38-Tz-NPs). To target tumor cells with the Tz-NPs, the tumor cells are first treated with TCO-Trb. The TCO-Trb binds HER2s and presents multiple TCO groups on the cell surface. Subsequently, the cells are treated with SN38-Tz-NPs that can bind the cell surface via click chemistry between Tz and TCO. This click chemistry-mediated binding resulted in enhanced tumor-targeting of Tz-NPs to the target tumor cells. In our study, this strategy was performed and analyzed in vitro and in vivo, and the results show that this is a promising strategy for tumor-targeted drug delivery by NPs.

Targeting EGFR of triple-negative breast cancer enhances the therapeutic efficacy of paclitaxel- and cetuximab-conjugated nanodiamond nanocomposite

Breast cancer is the most common malignancy and a leading cause of cancer-related mortality among women worldwide. Triple-negative breast cancer (TNBC) is characterized by the lack of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER2). However, epidermal growth factor receptor (EGFR) is highly expressed in most of the TNBCs, which may provide a potential target for EGFR targeting therapy. Nanodiamond (ND) is a carbon-based nanomaterial with several advantages, including fluorescence emission, biocompatibility, and drug delivery applications. In this study, we designed a nanocomposite by using ND conjugated with paclitaxel (PTX) and cetuximab (Cet) for targeting therapy on the EGFR-positive TNBC cells. ND-PTX inhibited cell viability and induced mitotic catastrophe in various human breast cancer cell lines (MDA-MB-231, MCF-7, and BT474); in contrast, ND alone did not induce cell death. ND-PTX inhibited the xenografted human breast tumors in nude mice. We further investigated ND-PTX-Cet drug efficacy on the TNBC of MDA-MB-231 breast cancer cells. ND-PTX-Cet could specifically bind to EGFR and enhanced the anticancer effects including drug uptake levels, mitotic catastrophe, and apoptosis in the EGFR-expressed MDA-MB-231 cells but not in the EGFR-negative MCF-7 cells. In addition, ND-PTX-Cet increased the protein levels of active caspase-3 and phospho-histone H3 (Ser10). Furthermore, ND-PTX-Cet showed more effective on the reduction of TNBC tumor volume by comparison with ND-PTX. Taken together, these results demonstrated that ND-PTX-Cet nanocomposite enhanced mitotic catastrophe and apoptosis by targeting EGFR of TNBC cells, which can provide a feasible strategy for TNBC therapy. STATEMENT OF SIGNIFICANCE: Current TNBC treatment is ineffective against the survival rate of TNBC patients. Therefore, the development of new treatment strategies for TNBC patients is urgently needed. Here, we have designed a nanocomposite by targeting on the EGFR of TNBC to enhance therapeutic efficacy by ND-conjugated PTX and Cet (ND-PTX-Cet). Interestingly, we found that the co-delivery of Cet and PTX by ND enhanced the apoptosis, mitotic catastrophe and tumor inhibition in the EGFR-expressed TNBC in vitro and in vivo. Consequently, this nanocomposite ND-PTX-Cet can be applied for targeting EGFR of human TNBC therapy.

Enhanced targeting of prostate cancer-initiating cells by salinomycin-encapsulated lipid-PLGA nanoparticles linked with CD44 antibodies

Prostate cancer is the fifth most common cause of cancer-associated mortality in males worldwide. The survival of prostate cancer-initiating cells (CICs) is an important factor behind the metastasis and recurrence of prostate cancer. The cluster of differentiation (CD) 44 antigen is considered an important marker for prostate CICs. Salinomycin is a potent therapeutic drug against CICs. The present study demonstrated that salinomycin exerts potent activity against CD44⁺ prostate CICs. To further enhance this anticancer effect, salinomycin-encapsulated lipid-poly(lactic-co-glycolic acid) nanoparticles linked with CD44 antibodies (SM-LPN-CD44) were generated. The anticancer effect of the nanoparticles was investigated in a series of assays, including a cytotoxicity assay, flow cytometry and anticancer assay in prostate cancer-bearing mice in vivo. The results revealed that SM-LPN-CD44 could efficiently and specifically promote the delivery of salinomycin to CD44⁺ prostate CICs, and there by achieve greater inhibition of the cells compared with that achieved by salinomycin and non-targeted nanoparticles. To the best of our knowledge, this is the first study to report improved therapeutic effects against prostate CICs achieved by the enhancement of targeted drug delivery via nanoparticles conjugated with CD44 antibodies. Therefore, SM-LPN-CD44 nanoparticle-based therapy represents a novel approach to eliminate prostate CICs and is a promising potential treatment strategy for prostate cancer.

Lipid-polymer nanoparticles with CD133 aptamers for targeted delivery of all-trans retinoic acid to osteosarcoma initiating cells

Osteosarcoma, a common type of bone cancer in children, and represents an aggressive and fetal cancer worldwide. Osteosarcoma initiating cells are considered to be a subpopulation of cancer cells which contribute to the progression, recurrence, metastasis and multi-drug resistance of osteosarcoma. CD133 is considered to be one marker for osteosarcoma initiating cells. All-trans retinoic acid (ATRA), an active metabolite of vitamin A under the family retinoid, is an up-and-coming drug which was able to effectively treat various cancer initiating cells. Nevertheless, there have been no research that reported the activity of ATRA against osteosarcoma initiating cells. In this research, we hereby examined the potential activity of ATRA in osteosarcoma initiating cells, and developed lipid-polymer nanoparticles with CD133 aptamers for targeted ATRA delivery to osteosarcoma initiating cells. Using the cytotoxicity assay, colony formation assay, tumorsphere formation assay and flow cytometry, the therapeutic effect of ATRA and ATRA-loaded lipid-polymer nanoparticles conjugated with CD133 aptamers (ATRA-PLNP-CD133) against osteosarcoma initiating cells were investigated. The results showed that ATRA exerted potent activity towards osteosarcoma initiating cells. ATRA-PLNP-CD133, which showed a size of 129.9 nm and a sustained release of ATRA during 144 h, was demonstrated to efficiently and specifically promote the ATRA delivery to osteosarcoma initiating cells, and achieve superior therapeutic efficacy in osteosarcoma compared with ATRA and non-targeted nanoparticles. This is the first report of the therapeutic efficacy of ATRA towards osteosarcoma initiating cells, and the increased ATRA delivery by nanoparticles to osteosarcoma initiating cells using CD133 aptamers. ATRA-PLNP-CD133 represent an up-and coming approach for the therapy of osteosarcoma initiating cells.

Targeted eradication of gastric cancer stem cells by CD44 targeting USP22 small interfering RNA-loaded nanoliposomes

AIM

USP22, a member of ubiquitin-specific proteases (USPs), is a well-defined protein that promotes poor prognosis, invasion and metastasis, and also participates in the maintenance of cancer stem cells. USP22 siRNA-loaded nanoliposomes conjugated with CD44 antibodies (USP22-NLs-CD44) were constructed to enhance the therapeutic effect of USP22 siRNA against gastric cancer stem cells.

MATERIALS & METHODS

The targeting and therapeutic efficacies of USP22-NLs-CD44 against gastric cancer stem cells were evaluated.

RESULTS & CONCLUSION

USP22-NLs-CD44 was demonstrated to be able to effectively deliver USP22 siRNA to CD44⁺ gastric cancer stem cells, achieving superior therapeutic effects against CD44⁺ gastric cancer stem cells than nontargeted nanoliposomes. USP22-NLs-CD44 may provide a novel approach to eradicate gastric cancer stem cells in the near future.

SATB1 siRNA-encapsulated immunoliposomes conjugated with CD44 antibodies target and eliminate gastric cancer-initiating cells

Purpose

Gastric cancer, the cancer initiated from the stomach, is ranked as the third most frequent reason of cancer death worldwide. Gastric cancer-initiating cells (CICs) are one of the crucial causes for the metastasis and recurrence of gastric cancer, and CD44 is considered to be one marker for gastric CICs. Special AT-rich sequence binding protein 1 (SATB1) is a protein that promotes cancer progression, metastasis, and invasion and also participates in the maintenance of CICs. In this study, we investigated the therapeutic effect of SATB1 siRNA against gastric CICs and we constructed SATB1 siRNA-encapsulated immunoliposomes conjugated with CD44 antibodies (CD44-SATB1-ILs) to enhance the therapeutic effect of SATB1 siRNA against gastric CICs.

Methods

We investigated the therapeutic effect of the SATB1 suppression by SATB1 siRNA on CD44⁺ gastric CICs. CD44-SATB1-ILs were developed by the lyophilization/hydration approach. The targeting and cytotoxic effect of CD44-SATB1-ILs toward gastric CICs were evaluated in vitro.

Results

In this study, for the first time, we confirmed that SATB1 suppression by SATB1 siRNA preferentially eliminated CD44⁺ gastric CICs. The results showed that CD44-SATB1-ILs could efficiently and specifically promote the SATB1 siRNA delivery to CD44⁺ gastric CICs, achieving superior therapeutic effects against CD44⁺ gastric CICs than non-targeted liposomes.

Conclusion

As far as we know, our report is the first research that indicated the promotion of siRNA delivery via nanoparticles to gastric CICs and achievement of superior therapeutic effect against gastric CICs by utilization of CD44 antibody. Therefore, CD44-SATB1-ILs represent an up-and-coming approach for eliminating gastric CICs and also a promising treatment for therapy of gastric cancer.

All-trans retinoic acid-encapsulated, CD20 antibody-conjugated poly(lactic-co-glycolic acid) nanoparticles effectively target and eliminate melanoma-initiating cells in vitro

Purpose

Melanoma, which is initiated from melanocytes, is the most fatal type of skin cancer. Melanoma-initiating cells significantly contribute to the initiation, metastasis, and recurrence of melanoma, and CD20 is a marker of melanoma-initiating cells. All-trans retinoic acid (ATRA) has been demonstrated to induce differentiation, inhibit proliferation, and promote the apoptosis of cancer cells and cancer-initiating cells (CICs). However, there has been no report on ATRA activity against melanoma-initiating cells. In this study, we examined the activity of ATRA against melanoma-initiating cells and developed ATRA-encapsulated poly(lactic-co-glycolic acid) (PLGA) nanoparticles, which were conjugated with a CD20 antibody (ATRA-PNP-CD20) for targeted delivery of ATRA to CD20⁺ melanoma-initiating cells.

Materials and methods

The effects of ATRA and ATRA-PNP-CD20 against melanoma-initiating cells were investigated using a cytotoxicity assay, tumorsphere formation assay, and flow cytometry.

Results

ATRA-PNP-CD20 had a size of 126.9 nm and a negative zeta potential. The drug-loading capacity of ATRA-PNP-CD20 was 8.7%, and ATRA-PNP-CD20 displayed a sustained release of ATRA for 144 hours. The results showed that ATRA-PNP-CD20 could effectively and specifically deliver ATRA to CD20⁺ melanoma-initiating cells, achieving superior inhibitory effects against CD20⁺ melanoma-initiating cells compared with those of free ATRA and nontargeted nanoparticles. To the best of our knowledge, we report for the first time a potent activity of ATRA against CD20⁺ melanoma-initiating cells, targeted drug delivery of ATRA via nanoparticles to melanoma-initiating cells, and the achievement of a superior inhibitory effect against melanoma-initiating cells by using a CD20 antibody.

Conclusion

ATRA-PNP-CD20 represents a promising tool for eliminating melanoma-initiating cells and shows a potential for the therapy of melanoma.

Targeting lung cancer initiating cells by all-trans retinoic acid-loaded lipid-PLGA nanoparticles with CD133 aptamers

Lung cancer initiating cells represent a specific subpopulation of lung cancer cells, which significantly contribute to the initiation, metastasis and recurrence of lung cancer. CD133, initially considered a marker of stem cells, is now considered as a marker for lung cancer initiating cells. All-trans retinoic acid (RA) has been demonstrated to cause the differentiation, inhibition of proliferation, and apoptosis of cancer cells and cancer initiating cells. However, there have been no reports on the activity of RA against lung cancer initiating cells. In the present study, the activity of RA against lung cancer initiating cells was investigated by determining the cytotoxicity, and performing a tumorsphere assay and flow cytometry-based analysis. In addition, to promote the therapeutic effect of RA in CD133⁺ lung cancer initiating cells, RA-loaded lipid poly(lactic-co-glycolic acid) (PLGA) nanoparticles with CD133 aptamers (RA-LPNPs-CD133) were developed. The activity of RA and RA-LPNPs-CD133 against lung cancer initiating cells was also investigated. RA-LPNPs-CD133 had a size of 129.9 nm, and exhibited sustained release of RA during the 144-h period. For the first time, to the best of our knowledge, the present study demonstrated that RA exerted potent activity towards CD133⁺ lung cancer initiating cells. The results also showed that RA-LPNPs-CD133 efficiently and specifically promoted the delivery of RA to CD133⁺ lung cancer initiating cells, exhibiting superior inhibitory effects against CD133⁺ lung cancer initiating cells compared with non-targeted nanoparticles and RA. To the best of our knowledge, the present study is the first to report the promotion of RA delivery via nanoparticles to lung cancer initiating cells and achievement of a superior inhibitory effect against lung cancer initiating cells by the utilization of CD133 aptamers. Therefore, RA-LPNPs-CD133 represents a promising tool for the elimination of lung cancer initiating cells.

Tumor-specific delivery of therapeutic siRNAs by anti-EGFR immunonanoparticles

Background

Efficient target-specific siRNA delivery has always been a primary concern in the field of siRNA clinical application.

Purpose

In this study, four different types of anti-epidermal growth factor receptor (EGFR) antibody-conjugated immunonanoparticles were prepared and tested for cancer cell-targeted therapeutic siRNA delivery.

Materials and methods

The prepared nanoparticles encapsulating siRNAs were character-ized by gel retardation and particle analysis using a Zetasizer. In vitro transfection and reduction of target genes, vimentin and JAK3, were determined using quantitative reverse transcription polymerase chain reaction. In vivo tumor targeting and antitumoral efficacies of the nanoparticles were evaluated in mice carrying tumors.

Results

Among these immunonanoparticles, anti-EGFR immunolipoplexes and immunoviroplexes exhibited remarkable cell binding and siRNA delivery to EGFR-expressing tumor cells compared to immunoliposomes and immunovirosomes. Especially, the anti-EGFR immunoviroplexes exhibited the most efficient siRNA transfection to target tumor cells. Therefore, antitumoral vimentin and Janus kinase-3 siRNAs were loaded in the anti-EGFR immunolipoplexes and immunoviroplexes, which were tested in mice carrying SK-OV-3 tumor xenografts. In fact, the therapeutic siRNAs were efficiently delivered to the tumor tissues by both delivery vehicles, resulting in significant inhibition of tumor growth. Moreover, administration of doxorubicin in combination with anti-EGFR immunoviroplexes resulted in remarkable and synergistic tumor growth inhibition.

Conclusion

This study provides experimental proof that cancer cell-targeted immunoviroplexes are an efficient siRNA delivery system for cancer therapy. Moreover, this study also suggests that a combination of conventional chemotherapy and tumor-directed anticancer siRNA therapy would be a better modality for cancer treatment.

EGFR aptamer-conjugated liposome-polycation-DNA complex for targeted delivery of SATB1 small interfering RNA to choriocarcinoma cells

Choriocarcinoma is a highly aggressive and vascular cancer. The main treatment for choriocarcinoma is the chemotherapy associated with severe side effects. Therefore, the development of novel strategies to eliminate choriocarcinoma is crucial for increasing the health of women. SATB1 (special AT-rich sequence binding protein 1) participates in tissue-specific gene expression and higher-order chromatin organization, and could promote cancer progression and invasion. For the first time, we hereby demonstrated that the expression of SATB1 was increased by 19 folds in choriocarcinoma cells compared with the normal chorionic cell line, and inhibition of SATB1 expression could markedly inhibit the proliferation of choriocarcinoma cells. Then we developed the gene drug delivery system EGFR-LPDS (epidermal growth factor receptor aptamer-conjugated liposome-polycation-DNA complex loaded with SATB1 siRNA) to increase the delivery and therapeutic effect of SATB1 siRNA against choriocarcinoma cells. The results showed that EGFR-LPDS could specifically target choriocarcinoma cells, resulting in significant inhibition of SATB1 expression, growth inhibitory effect and apoptosis in EGFR over-expressing choriocarcinoma cells in vitro. Notably, EGFR-LPDS could inhibit the expression of SATB1 in choriocarcinoma xenograft in mice, and exhibited the best therapeutic efficacy against mice bearing choriocarcinoma xenograft compared with other controls. Notably, EGFR-LPDS achieved a striking tumor weight inhibitory rate of 81.4%. This is the first report of the therapeutic efficacy of SATB1 siRNA towards choriocarcinoma, and the increased SATB1 siRNA delivery by nanoparticles to choriocarcinoma cells using EGFR aptamers. Thus, EGFR-LPDS represents an up-and coming approach for choriocarcinoma therapy. Considering that there are still limited treatment strategies for choriocarcinoma therapy, patients with choriocarcinoma may be beneficial from this gene therapy.

Core-shell nanoparticles for targeted and combination antiretroviral activity in gut-homing T cells

A major sanctuary site for HIV infection is the gut-associated lymphoid tissue (GALT). The α4β7 integrin gut homing receptor is a promising therapeutic target for the virus reservoir because it leads to migration of infected cells to the GALT and facilitates HIV infection. Here, we developed a core-shell nanoparticle incorporating the α4β7 monoclonal antibody (mAb) as a dual-functional ligand for selectively targeting a protease inhibitor (PI) to gut-homing T cells in the GALT while simultaneously blocking HIV infection. Our nanoparticles significantly reduced cytotoxicity of the PI and enhanced its in vitro antiviral activity in combination with α4β7 mAb. We demonstrate targeting function of our nanocarriers in a human T cell line and primary cells isolated from macaque ileum, and observed higher in vivo biodistribution to the murine small intestines where they accumulate in α4β7+ cells. Our LCNP shows the potential to co-deliver ARVs and mAbs for eradicating HIV reservoirs.

Enhanced rapamycin delivery to hemangiomas by lipid polymer nanoparticles coupled with anti-VEGFR antibody

The most common tumors in children are infantile hemangiomas which could cause morbidity and severe complications. The development of novel alternative drugs to treat infantile hemangiomas is necessary, since Hemangeol is the only US Food and Drug Administration-approved drug for infantile hemangiomas. However, Hemangeol has several disadvantages, including a high frequency of administration and adverse effects. Rapamycin is a well‑established antiangiogenic drug, and we have previously developed rapamycin lipid polymer nanoparticles (R‑PLNPs) as a local sustained‑release drug delivery system to achieve controlled rapamycin release and to decrease the frequency of administration and side effects of rapamycin. To improve the targeting of R‑PLNPs to infantile hemangiomas in the present study, R‑PLNPs were modified to include an antibody against vascular endothelial growth factor receptor (VEGF). The characteristics, and the anti‑hemangioma activity of the resulting R‑PLNPs coupled with the anti‑VEGFR2 antibody (named R‑PLNPs‑V) were examined in vitro and in vivo. R‑PLNPs‑V possessed a small size (115 nm) and sustained drug release for 6 days. The anti‑VEGFR2 antibody promoted the targeting and cytotoxic effect of R‑PLNPs‑V to human hemangioma endothelial cells and human umbilical vein endothelial cells. Using a subcutaneous infantile hemangioma xenograft in mice, the in vivo therapeutic effect (evaluated with hemangioma weight, volume, and microvessel density) of R‑PLNPs‑V was demonstrated to be superior compared with rapamycin alone and other non‑targeted nanoparticles, without any total body weight loss. In summary, R‑PLNPs‑V could facilitate targeted delivery and sustained release of rapamycin to infantile hemangiomas, and thus may represent a promising candidate treatment for infantile hemangiomas.

Salinomycin-loaded lipid-polymer nanoparticles with anti-CD20 aptamers selectively suppress human CD20+ melanoma stem cells

Melanoma is the deadliest type of skin cancer. CD20+ melanoma stem cells (CSCs) are pivotal for metastasis and initiation of melanoma. Therefore, selective elimination of CD20+ melanoma CSCs represents an effective treatment to eradicate melanoma. Salinomycin has emerged as an effective drug toward various CSCs. Due to its poor solubility, its therapeutic efficacy against melanoma CSCs has never been evaluated. In order to target CD20+ melanoma CSCs, we designed salinomycin-loaded lipid-polymer nanoparticles with anti-CD20 aptamers (CD20-SA-NPs). Using a single-step nanoprecipitation method, salinomycin-loaded lipid-polymer nanoparticles (SA-NPs) were prepared, then CD20-SA-NPs were obtained through conjugation of thiolated anti-CD20 aptamers to SA-NPs via a maleimide-thiol reaction. CD20-SA-NPs displayed a small size of 96.3 nm, encapsulation efficiency higher than 60% and sustained drug release ability. The uptake of CD20-SA-NPs by CD20+ melanoma CSCs was significantly higher than that of SA-NPs and salinomycin, leading to greatly enhanced cytotoxic effects in vitro, thus the IC₅₀ values of CD20-SA-NPs were reduced to 5.7 and 2.6 μg/mL in A375 CD+20 cells and WM266-4 CD+ cells, respectively. CD20-SA-NPs showed a selective cytotoxicity toward CD20+ melanoma CSCs, as evidenced by the best therapeutic efficacy in suppressing the formation of tumor spheres and the proportion of CD20+ cells in melanoma cell lines. In mice bearing melanoma xenografts, administration of CD20-SA-NPs (salinomycin 5 mg·kg^-1·d^-1, iv, for 60 d) showed a superior efficacy in inhibition of melanoma growth compared with SA-NPs and salinomycin. In conclusion, CD20 is a superior target for delivering drugs to melanoma CSCs. CD20-SA-NPs display effective delivery of salinomycin to CD20+ melanoma CSCs and represent a promising treatment for melanoma.

Epidermal growth factor receptor aptamer-conjugated polymer-lipid hybrid nanoparticles enhance salinomycin delivery to osteosarcoma and cancer stem cells

Osteosarcoma is a common childhood bone cancer with a poor survival rate. Osteosarcoma cancer stem cells (CSCs) contribute to the recurrence, drug resistance and metastasis of this disease. Previous evidence suggested that cancer cells are able to spontaneously turn into CSCs, thus it is crucial to simultaneously target osteosarcoma cells and CSCs. Our previous studies have demonstrated that salinomycin preferably eliminated osteosarcoma CSCs. In addition, amplification of the epidermal growth factor receptor (EGFR) is a common genetic aberration in osteosarcoma, and thus EGFR is a promising target in osteosarcoma. The present study aimed to develop EGFR aptamer-conjugated salinomycin-loaded polymer-lipid hybrid nanoparticles (EGFR-SNPs) to target both osteosarcoma cells and CSCs. The results revealed that EGFR was overexpressed in these cells, and that EGFR-SNPs possessed a small size of 95 nm, suitable drug encapsulation efficiency (63%) and sustained drug release over 120 h. EGFR-SNPs targeted EGFR-overexpressing osteosarcoma cells and CSCs, resulting in an enhanced cytotoxic effect compared with non-targeted SNPs and salinomycin. Notably, EGFR-SNPs was able to reduce the osteosarcoma tumorsphere formation rate and proportion of CD133⁺ osteosarcoma CSCs in the osteosarcoma cell lines more effectively compared with SNPs and salinomycin, suggesting that EGFR-SNPs effectively reduced the proportion of osteosarcoma CSCs. In conclusion, the interaction of EGFR aptamers and EGFR is a potential approach to promote the effective delivery of salinomycin to osteosarcoma. The study results suggested that EGFR-SNPs represents a promising approach to target osteosarcoma cells and CSCs.

Polymer-lipid hybrid anti-HER2 nanoparticles for targeted salinomycin delivery to HER2-positive breast cancer stem cells and cancer cells

PURPOSE

Breast cancer stem cells (CSCs) are responsible for the initiation, recurrence, and metastasis of breast cancer. Sufficient evidence has established that breast cancer cells can spontaneously turn into breast CSCs. Thus, it is essential to simultaneously target breast CSCs and cancer cells to maximize the efficacy of breast cancer therapy. HER2 has been found to be overexpressed in both breast CSCs and cancer cells. We developed salinomycin-loaded polymer-lipid hybrid anti-HER2 nanoparticles (Sali-NP-HER2) to target both HER2-positive breast CSCs and cancer cells.

METHODS

The antitumor activity of Sali-NP-HER2 constructed by conjugating anti-HER2 antibodies to polymer-lipid salinomycin nanoparticles was evaluated in vitro and in vivo.

RESULTS

Sali-NP-HER2 efficiently bound to HER2-positive breast CSCs and cancer cells, resulting in enhanced cytotoxic effects compared with non-targeted nanoparticles or salinomycin. In mice bearing breast cancer xenografts, administration of Sali-NP-HER2 exhibited superior efficacy in inhibiting tumor growth. Sali-NP-HER2 reduced the breast tumorsphere formation rate and the proportion of breast CSCs more effectively than non-targeted nanoparticles or salinomycin alone.

CONCLUSION

Sali-NP-HER2 represents a promising approach in treating HER2-positive breast cancer by targeting both breast CSCs and cancer cells.

Gefitinib-loaded DSPE-PEG2000 nanomicelles with CD133 aptamers target lung cancer stem cells

Background

Lung cancer stem cells (CSCs) are considered to be the seed of lung cancer, and CD133 is a marker of lung CSCs. Here, we developed gefitinib-loaded poly(ethylene glycol) 2000-distearoylphosphatidylethanolamine nanomicelles with CD133 aptamers (M-Gef-CD133) to eliminate CD133⁺ lung CSCs.

Methods

M-Gef-CD133 was prepared using a lipid-film-based approach. The targeting and activity of M-Gef-CD133 towards lung CSCs were evaluated.

Results

M-Gef-CD133 were small (25 nm) and showed enhanced cytotoxic effect towards CD133⁺ lung CSCs compared with non-targeted M-Gef and gefitinib. Notably, M-Gef-CD133 could significantly reduce tumor sphere formation and the percentage of CD133⁺ lung CSCs, indicating that it possesses selective toxicity against CD133⁺ lung CSCs.

Conclusions

The interaction of CD133 aptamers and CD133 shows promise in the delivery of gefitinib to CD133⁺ lung CSCs, and M-Gef-CD133 represents a promising treatment to target lung CSCs.

Statins anticancer targeted delivery systems: re-purposing an old molecule

OBJECTIVES

Exploring the use of statins as anticancer agents and exploiting different drug delivery systems in targeting these molecules to cancerous sites. Literature review was performed to investigate the use of statins in cancer treatment in one hand, and the different pharmaceutical approaches to deliver and target these drugs to their site of action.

KEY FINDINGS

Statins were used for decades as antihypercholestrolemic drugs but recently have been proven potential for broad anticancer activities. The incorporation of statins in nanoparticulate drug delivery systems not only augmented the cytotoxicity of statins but also overcame the resistance of cancerous cells against the traditional chemotherapeutic agents. Statins-loaded nanoparticles could be easily tampered to target the cancerous cells and consequently minimal drug amount could be utilized.

SUMMARY

This review reconnoitered the different endeavors to incorporate statins in various nanoparticles and summarized the successful effects in targeting cancerous cells and reducing their proliferation without the side effects of commonly used chemotherapeutic agents.

Cationic liposomes promote antigen cross-presentation in dendritic cells by alkalizing the lysosomal pH and limiting the degradation of antigens

Cationic liposomes (CLs) have been widely examined as vaccine delivery nanoparticles since they can form complexes with biomacromolecules, promote delivery of antigens and adjuvant molecules to antigen-presenting cells (APCs), and mediate cellular uptake of vaccine components. CLs are also known to trigger antigen cross-presentation - the process by which APCs internalize extracellular protein antigens, degrade them into minimal CD8⁺ T-cell epitopes, and present them in the context of major histocompatibility complex-I (MHC-I). However, the precise mechanisms behind CL-mediated induction of cross-presentation and cross-priming of CD8⁺ T-cells remain to be elucidated. In this study, we have developed two distinct CL systems and examined their impact on the lysosomal pH in dendritic cells (DCs), antigen degradation, and presentation of peptide:MHC-I complexes to antigen-specific CD8⁺ T-cells. To achieve this, we have used 3β-[N-(N',N'-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol) and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) as the prototypical components of CLs with tertiary amine groups and compared the effect of CLs and anionic liposomes on lysosomal pH, antigen degradation, and cross-presentation by DCs. Our results showed that CLs, but not anionic liposomes, elevated the lysosomal pH in DCs and reduced antigen degradation, thereby promoting cross-presentation and cross-priming of CD8⁺ T-cell responses. These studies shed new light on CL-mediated cross-presentation and suggest that intracellular fate of vaccine components and subsequent immunological responses can be controlled by rational design of nanomaterials.

Mannose-coated gadolinium liposomes for improved magnetic resonance imaging in acute pancreatitis

Background

Acute pancreatitis (AP) is an acute inflammatory condition of the pancreas. The symptoms, treatment, and prognosis of mild and severe AP are different, and severe AP is a potentially life-threatening disease with a high incidence of complications and high mortality rate. Thus, it is urgent to develop an effective approach to reliably discriminate between mild and severe AP.

Methods

We have developed novel gadolinium-diethylenetriaminepentaacetic (Gd-DTPA)-loaded mannosylated liposomes (named thereafter M-Gd-NL) that preferably target macrophages in AP. The targeting ability of M-Gd-NL toward macrophages in AP and its ability to discriminate between mild and severe AP were evaluated.

Results

The liposomes were of desired particle size (~100 nm), Gd-DTPA encapsulation efficiency (~85%), and stability. M-Gd-NL and non-targeted Gd-DTPA-loaded liposomes (Gd-NL) exhibited increased relaxivity compared with Gd-DTPA. Compared with Gd-NL and Gd-DTPA, M-Gd-NL showed increased uptake in macrophages, resulting in increased T₁ imaging ability both in vitro (macrophage cell line) and in vivo (severe AP model). Importantly, M-Gd-NL had the ability to discriminate between mild and severe AP, as reflected by a significantly higher T₁ magnetic resonance imaging signal in severe AP than in mild AP. M-Gd-NL did not show severe organ toxicity in rats.

Conclusion

Our data suggest that M-Gd-NL had enhanced magnetic resonance imaging ability by targeting macrophages in AP and good ability to discriminate between mild and severe AP. We believe that M-Gd-NL could shed new light on the diagnosis of AP in the near future.

Nanomedicine strategies for sustained, controlled and targeted treatment of cancer stem cells

Cancer stem cells (CSCs) are original cancer cells that are of characteristics associated with normal stem cells. CSCs are toughest against various treatments and thus responsible for cancer metastasis and recurrence. Therefore, development of specific and effective treatment of CSCs plays a key role in improving survival and life quality of cancer patients, especially those in the metastatic stage. Nanomedicine strategies, which include prodrugs, micelles, liposomes and nanoparticles of biodegradable polymers, could substantially improve the therapeutic index of conventional therapeutics due to its manner of sustained, controlled and targeted delivery of high transportation efficiency across the cell membrane and low elimination by intracellular autophagy, and thus provide a practical solution to solve the problem encountered in CSCs treatment. This review gives briefly the latest information to summarize the concept, strategies, mechanisms and current status as well as future promises of nanomedicine strategies for treatment of CSCs.

Codelivery of salinomycin and doxorubicin using nanoliposomes for targeting both liver cancer cells and cancer stem cells

Aim: To develop salinomycin-loaded nanoliposomes (SLN), doxorubicin-loaded nanoliposomes (DLN) and nanoliposomes codelivering salinomycin and doxorubicin (SDLN) to target both liver cancer cells and cancer stem cells. Materials & methods: The characterization and antitumor activity of SLN, DLN and SDLN were evaluated. Results & conclusion: The doxorubicin/salinomycin sodium mole ratio of 1:1 had the best synergistic combination index value, and was chosen as the drug ratio in SDLN. SDLN could maintain the drug ratio between 1:1 and 3:1 in 12 h in vivo. SDLN and SLN + DLN showed the best tumor inhibitory rate, and could significantly decrease the percentage of liver cancer stem cells in vivo. SDLN and SLN + DLN may serve as an effective approach to treat liver cancer.

Novel targets for paclitaxel nano formulations: Hopes and hypes in triple negative breast cancer

Triple negative breast cancer is defined as one of the utmost prevailing breast cancers worldwide, possessing an inadequate prognosis and treatment option limited to chemotherapy and radiotherapy, creating a challenge for researchers as far as developing a specific targeted therapy is concerned. The past research era has shown several promising outcomes for TNBC such as nano-formulations of the chemotherapeutic agents already used for the management of the malignant tumor. Taking a glance at paclitaxel nano formulations, it has been proven beneficial in several researches in the past decade; nevertheless its solubility is often a challenge to scientists in achieving success. We have henceforth discussed the basic heterogeneity of triple negative breast cancer along with the current management options as well as a brief outlook on pros and cons of paclitaxel, known as the most widely used chemotherapeutic agent for the treatment of the disease. We further analyzed the need of nanotechnology pertaining to the problems encountered with the current paclitaxel formulations available discussing the strategic progress in various nano-formulations till date taking into account the basic research strategies required in terms of solubility, permeability, physicochemical properties, active and passive targeting. A thorough review in recent advances in active targeting for TNBC was carried out whereby the various ligands which are at present finding its way into TNBC research such as hyaluronic acid, folic acid, transferrin, etc. were discussed. These ligands have specific receptor affinity to TNBC tumor cells hence can be beneficial for novel drug targeting approaches. Conversely, there are currently several novel strategies in the research pipeline whose targeting ligands have not yet been studied. Therefore, we reviewed upon the numerous novel receptor targets along with the respective nano-formulation aspects which have not yet been fully researched upon and could be exemplified as outstanding target strategies for TNBC which is currently an urgent requirement.

Codelivery of salinomycin and chloroquine by liposomes enables synergistic antitumor activity in vitro

Aim: To improve the suboptimal therapeutic efficacy of salinomycin (SAL) toward liver cancer cells using chloroquine (CQ) combination by the liposomes co-delivering SAL and CQ (SCNL). Materials & methods: The synergy of these two drugs was evaluated in liver cancer cells (HepG2) and liver cancer stem cells (LCSCs) by median-effect analysis. SCNL with optimized ratio were developed. The cytotoxic effect and basal autophagy flux (measure of autophagic degradation activity) of various formulations were evaluated. Results & conclusion: CQ could significantly increase the cytotoxic effect of SAL in HepG2 cells, but not in HepG2-LCSCs, due to the greater basal autophagy flux in HepG2 cells. This combination therapy is promising for liver cancer treatment by eradicating liver cancer cells and LCSCs.

Antibody-targeted biodegradable nanoparticles for cancer therapy

The use of nanotechnology has great potentials to revolutionize the future cancer diagnosis and therapy. In this context, various nanoparticles (NPs) have been developed for targeted delivery of diagnostic/therapeutic agents to the tumor sites, which thus result in greater efficacy and much less side effects. The targeting property of NPs is often achieved by functionalizing their surface with tumor-specific ligands, such as antibodies, peptides, small molecules and oligonucleotides. In this review, we will discuss recent progress in the multifunctional design of antibody-targeted NPs with a special focus on liposomal, polymeric and protein-based delivery systems.

Nucleolin-targeting liposomes guided by aptamer AS1411 for the delivery of siRNA for the treatment of malignant melanomas

BRAF gene mutation is found in more than 60% of malignant melanomas, which are difficult to treat. In this study, a new tumor-targeting liposome was developed to deliver anti-BRAF siRNA (siBraf) for the treatment of melanomas. Nucleolin is overexpressed on the surface of cancer cells. AS1411, an aptamer showing specific binding to nucleolin, was conjugated to PEGylated cationic liposome as the targeting probe ASLP (AS1411-PEG-liposome). The ASLP/siRNA complex was formed through electrostatic interaction between ASLP and siRNA. The binding of AS1411 to the surface of PEGylated liposomes was confirmed by gel electrophoresis and capillary electrophoresis. Real-time PCR and Western blot analysis showed that ASLP/siBraf exhibited strong silencing activity of BRAF gene. The much higher accumulation of the siRNA in tumor cells comparing with normal cells indicated that ASLP displayed excellent tumor-targeting capability. Notably, ASLP/siBraf showed significant silencing activity in A375 tumor xenograft mice and inhibited the melanoma growth. These results suggested that the new nucleolin-targeted siRNA delivery system by AS1411 may have the potential for the treatment of melanoma.

Cancer nanotechnology: the impact of passive and active targeting in the era of modern cancer biology

Cancer nanotherapeutics are progressing at a steady rate; research and development in the field has experienced an exponential growth since early 2000's. The path to the commercialization of oncology drugs is long and carries significant risk; however, there is considerable excitement that nanoparticle technologies may contribute to the success of cancer drug development. The pace at which pharmaceutical companies have formed partnerships to use proprietary nanoparticle technologies has considerably accelerated. It is now recognized that by enhancing the efficacy and/or tolerability of new drug candidates, nanotechnology can meaningfully contribute to create differentiated products and improve clinical outcome. This review describes the lessons learned since the commercialization of the first-generation nanomedicines including DOXIL® and Abraxane®. It explores our current understanding of targeted and non-targeted nanoparticles that are under various stages of development, including BIND-014 and MM-398. It highlights the opportunities and challenges faced by nanomedicines in contemporary oncology, where personalized medicine is increasingly the mainstay of cancer therapy. We revisit the fundamental concepts of enhanced permeability and retention effect (EPR) and explore the mechanisms proposed to enhance preferential "retention" in the tumor, whether using active targeting of nanoparticles, binding of drugs to their tumoral targets or the presence of tumor associated macrophages. The overall objective of this review is to enhance our understanding in the design and development of therapeutic nanoparticles for treatment of cancers.

Nano polymeric carrier fabrication technologies for advanced antitumor therapy

Comparing with the traditional therapeutic methods, newly developed cancer therapy based on the nanoparticulates attracted extensively interest due to its unique advantages. However, there are still some drawbacks such as the unfavorable in vivo performance for nanomedicine and undesirable tumor escape from the immunotherapy. While as we know that the in vivo performance strongly depended on the nanocarrier structural properties, thus, the big gap between in vitro and in vivo can be overcome by nanocarrier's structural tailoring by fine chemical design and microstructural tuning. In addition, this fine nanocarrier's engineering can also provide practical solution to solve the problems in traditional cancer immunotherapy. In this paper, we review the latest development in nanomedicine, cancer therapy, and nanoimmunotherapy. We then give an explanation why fine nanocanrrie's engineering with special focus on the unique pathology of tumor microenvironments and properties of immunocells can obviously promote the in vivo performance and improve the therapeutic index of nanoimmunotherapy.

Inhibition of hepatocellular carcinoma growth using immunoliposomes for co-delivery of adriamycin and ribonucleotide reductase M2 siRNA

The chemotherapy combined with gene therapy has received great attention. We developed targeted LPD (liposome-polycation-DNA complex) conjugated with anti-EGFR (epidermal growth factor receptor) Fab' co-delivering adriamycin (ADR) and ribonucleotide reductase M2 (RRM2) siRNA (ADR-RRM2-TLPD), to achieve combined therapeutic effects in human hepatocellular carcinoma (HCC) overexpressing EGFR. The antitumor activity and mechanisms of ADR-RRM2-TLPD were investigated. The results showed that RRM2 expression was higher in HCC than in non-HCC tissue, and RRM2 siRNA inhibited HCC cell proliferation, suggesting that RRM2 is a candidate target for HCC therapy. ADR-RRM2-TLPD delivered ADR and RRM2 siRNA to EGFR overexpressing HCC cells specifically and efficiently both in vitro and in vivo, resulting in enhanced therapeutic effects (cytotoxicity, apoptosis and senescence-inducing activity) compared with single-drug loaded or non-targeted controls, including ADR-NC-TLPD (targeted LPD co-delivering ADR and negative control siRNA), RRM2-TLPD (targeted LPD delivering RRM2 siRNA) and ADR-RRM2-NTLPD (non-targeted LPD co-delivering ADR and RRM2 siRNA). Mechanism studies showed that p21 is involved in the combined therapeutic effect of ADR-RRM2-TLPD. The average weight of the orthotopic HCC in mice treated with ADR-RRM2-TLPD was significantly lighter than that of mice treated with other controls. Thus, ADR-RRM2-TLPD represents a potential strategy for combined therapy of HCC overexpressing EGFR.

Polymer-lipid hybrid nanoparticles conjugated with anti-EGF receptor antibody for targeted drug delivery to hepatocellular carcinoma

AIMS

The aim of this study was to obtain adriamycin-loaded polymer-lipid hybrid nanoparticles conjugated with anti-EGF receptor antibody (PLNP-Mal-EGFR) for hepatocellular carcinoma (HCC) chemotherapy.

MATERIALS & METHODS

The nanoparticles were characterized by dynamic light scattering and fluorescence spectroscopy. The in vitro and in vivo distribution and anti-tumor activity of the nanoparticles were evaluated.

RESULTS & CONCLUSION

PLNP-Mal-EGFR showed significantly enhanced cellular cytotoxicity against HCC cells overexpressing EGFR compared with nontargeted nanoparticles (polymer-lipid hybrid nanoparticles [containing DSPE-PEG-Mal] and polymer-lipid hybrid nanoparticles [containing DSPE-mPEG] combined with anti-EGFR Fab´). PLNP-Mal-EGFR and nontargeted nanoparticles could significantly reduce the proportion of side-population cells in HCC cells. The in vivo accumulation of PLNP-Mal-EGFR was obviously higher than that of nontargeted nanoparticles in SMMC-7721 HCC cells overexpressing EGFR. Notably, PLNP-Mal-EGFR showed significantly enhanced anti-tumor activity against HCC in vivo compared with nontargeted nanoparticles and free adriamycin. Therefore, PLNP-Mal-EGFR may serve as an effective therapeutic approach for HCC chemotherapy.

A new nanoconstruct for epidermal growth factor receptor-targeted photo-immunotherapy of ovarian cancer

Targeted photodynamic therapy (TPDT) involves the administration of a photosensitizer (PS) conjugated with a targeting moiety followed by light activation. The systemic toxicity associated with conventional therapy may thus be significantly reduced in TPDT due to the dual selectivity provided by the spatial localization of the illumination as well as the target-localizing ability of the conjugate. Herein, a photo-immuno-conjugate-associating-liposome (PICAL) for TPDT has been developed in which the FDA approved benzoporphyrin derivative monoacid A (BPD) and the Cetuximab antibody for epidermal growth factor receptor (EGFR) were associated into a stable Preformed Plain Liposome (PPL) by passive physical adsorption. Results have shown that the BPD molecules adsorbed into PICAL have stable optical behavior and a higher fluorescence quantum yield than free-BPD. The Cetuximab adsorbed into PPL selectively binds to cells that overexpress EGFR. The inhibition of EGFR signaling by PICAL has enhanced PDT-mediated ovarian cancer cell death.

FROM THE CLINICAL EDITOR

In this basic science study, a photo-immuno-conjugate-associating-liposome for targeted photodynamic therapy is investigated. The FDA-approved benzoporphyrin derivative monoacid A and an epidermal growth factor receptor antibody were assembed into a stable Preformed Plain Liposome (PPL) by passive physical adsorption. The authors demonstrate therapeutic efficacy of the above construct in an ovarian tumor system.