Dual-Targeting Multifuntional Mesoporous Silica Nanocarrier for Codelivery of siRNA and Ursolic Acid to Folate Receptor Overexpressing Cancer Cells

Tuned Manganese-Impregnated Mesoporous Silica Nanoparticles as a pH-Responsive Dual Imaging Probe

The limitations of individual imaging modalities have led to significant interest in hybrid imaging methods that combine the advantages of multiple techniques. The development of diverse dual imaging agents, which offer the exceptional sensitivity of single-photon emission computed tomography (SPECT) and the high spatial resolution of magnetic resonance imaging (MRI), has been addressing the demand for more advanced diagnostic pharmaceuticals. In this study, 99mTc-labeled manganese oxide-loaded mesoporous silica nanoparticles (MSNs), conjugated with folic acid as the targeting moiety and the chelating agent H2pentapa-en-NH2 (99mTc-MnOx-MSN-FA-pa), were developed for targeted SPECT-MRI dual imaging. The toxicity of the nanoparticles was confirmed through an MTT assay, showing >90% viability in HEK-293 and MDA-MB-231 cells at concentrations up to 200 μg/mL, indicating nonsignificant toxicity. Cellular uptake studies showed that folic acid functionalization effectively accentuated tumor-specific intracellular uptake of nanoparticles in MDA-MB-231 cells through folate receptor-mediated endocytosis. Additionally, the radiolabeling yield of 99mTc-MnOx-MSN-FA-pa was found to be 99.6 ± 0.8% (n = 3), and the pH-responsive release of paramagnetic manganese ions increased the r1 relaxivity of the nanoprobe to 11.37 mM-1 s-1. In vivo SPECT imaging demonstrated rapid tracer accumulation in MDA-MB-231 xenografts, with a tumor-to-muscle ratio of 6.01 ± 0.51 at 2 h, and minimal uptake in nontargeted organs. In vivo MRI studies indicated the strongest tumor contrast at 2 h postinjection. Given its desirable contrast enhancement in T1 MRI and SPECT imaging, along with low toxicity, MnOx-MSN-FA-pa shows potential as an effective multifunctional nanoprobe for precise tumor imaging.

Hybrid Liposome-MSN System with Co-Delivering Potential Effective Against Multidrug-Resistant Tumor Targets in Mice Model

Introduction

RNA interference (RNAi) stands as a widely employed gene interference technology, with small interfering RNA (siRNA) emerging as a promising tool for cancer treatment. However, the inherent limitations of siRNA, such as easy degradation and low bioavailability, hamper its efficacy in cancer therapy. To address these challenges, this study focused on the development of a nanocarrier system (HLM-N@DOX/R) capable of delivering both siRNA and doxorubicin for the treatment of breast cancer.

Methods

The study involved a comprehensive investigation into various characteristics of the nanocarrier, including shape, diameter, Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), encapsulation efficiency, and drug loading. Subsequently, in vitro and in vivo studies were conducted on cytotoxicity, cellular uptake, cellular immunofluorescence, lysosome escape, and mouse tumor models to evaluate the efficacy of the nanocarrier in reversing tumor multidrug resistance and anti-tumor effects.

Results

The results showed that HLM-N@DOX/R had a high encapsulation efficiency and drug loading capacity, and exhibited pH/redox dual responsive drug release characteristics. In vitro and in vivo studies showed that HLM-N@DOX/R inhibited the expression of P-gp by 80%, inhibited MDR tumor growth by 71% and eliminated P protein mediated multidrug resistance.

Conclusion

In summary, HLM-N holds tremendous potential as an effective and targeted co-delivery system for DOX and P-gp siRNA, offering a promising strategy for overcoming MDR in breast cancer.

Triterpenoids-templated self-assembly nanosystem for biomimetic delivery of CRISPR/Cas9 based on the synergy of TLR-2 and ICB to enhance HCC immunotherapy

Combination immunotherapy has shown promising potential for enhancing the objective response rate compared to immune checkpoint blockade (ICB) monotherapy. However, combination therapy with multi-drugs is limited by the different properties of the agents and inconsistent synergistic targeted delivery. Herein, based on a universal triterpene template and the anticancer active agent ursolic acid (UA), a cytomembrane-coated biomimetic delivery nanoplatform (UR@M) prepared by the self-assembly of a PD-L1 targeted CRISPR/Cas9 system and UA was designed for hepatocellular carcinoma (HCC) treatment. UR@M showed enhanced tumor accumulation in vivo with homologous tumor targeting, and CRISPR in the nanosystem exhibited potent gene-editing efficiency of 76.53% in vitro and 62.42% in vivo with no off-target effects. UA activated the natural immune system through the TLR-2-MyD88-TRAF6 pathway, which synergistically enhanced the proliferation of natural killer cells and dendritic cells and realized excellent immune cytotoxic T cell infiltration by combining with the ICB of PD-L1. The strategy of work along both lines based on innate immune and adaptive immunity displayed a significant effect in tumor regression. Overall, the UA-templated strategy "killed three birds with one stone" by establishing a self-assembly nanosystem, inducing tumor cell death, and promoting synergistic immunostimulation for HCC treatment.

Engineered mesoporous silica nanoparticles, new insight nanoplatforms into effective cancer gene therapy

The use of nucleic acid to control the expression of genes relevant to tumor progression is a key therapeutic approach in cancer research. Therapeutics based on nucleic acid provide novel concepts for untreatable targets. Nucleic acids as molecular medications must enter the target cell to be effective and obstacles in the systemic delivery of DNA or RNA limit their use in a clinical setting. The creation of nucleic acid delivery systems based on nanoparticles in order to circumvent biological constraints is advancing quickly. The ease of synthesis and surface modification, biocompatibility, biodegradability, cost-effectiveness and high loading capability of nucleic acids have prompted the use of mesoporous silica nanoparticles (MSNs) in gene therapy. The unique surface features of MSNs facilitate their design and decoration for high loading of nucleic acids, immune system evasion, cancer cell targeting, controlled cargo release, and endosomal escape. Reports have demonstrated successful therapeutic outcomes with the administration of a variety of engineered MSNs capable of delivering genes to tumor sites in laboratory animals. This comprehensive review of studies about siRNA, miRNA, shRNA, lncRNA and CRISPR/Cas9 delivery by MSNs reveals engineered MSNs as a safe and efficient system for gene transfer to cancer cells and cancer mouse models.

Mesoporous silica nanoparticles: An emerging approach in overcoming the challenges with oral delivery of proteins and peptides

Proteins and peptides (PPs), as therapeutics are widely explored in the past few decades, by virtue of their inherent advantages like high specificity and biocompatibility with minimal side effects. However, owing to their macromolecular size, poor membrane permeability, and high enzymatic susceptibility, the effective delivery of PPs is often challenging. Moreover, their subjection to varying environmental conditions, when administered orally, results in PPs denaturation and structural conformation, thereby lowering their bioavailability. Hence, for effective delivery with enhanced bioavailability, protection of PPs using nanoparticle-based delivery system has gained a growing interest. Mesoporous silica nanoparticles (MSNs), with their tailored morphology and pore size, high surface area, easy surface modification, versatile loading capacity, excellent thermal stability, and good biocompatibility, are eligible candidates for the effective delivery of macromolecules to the target site. This review highlights the different barriers hindering the oral absorption of PPs and the various strategies available to overcome them. In addition, the potential benefits of MSNs, along with their diversifying role in controlling the loading of PPs and their release under the influence of specific stimuli, are also discussed in length. Further, the tuning of MSNs for enhanced gene transfection efficacy is also highlighted. Since extensive research is ongoing in this area, this review is concluded with an emphasis on the potential risks of MSNs that need to be addressed prior to their clinical translation.

Recent Advances in Mesoporous Silica Nanoparticles Delivering siRNA for Cancer Treatment

Silencing genes using small interfering (si) RNA is a promising strategy for treating cancer. However, the curative effect of siRNA is severely constrained by low serum stability and cell membrane permeability. Therefore, improving the delivery efficiency of siRNA for cancer treatment is a research hotspot. Recently, mesoporous silica nanoparticles (MSNs) have emerged as bright delivery vehicles for nucleic acid drugs. A comprehensive understanding of the design of MSN-based vectors is crucial for the application of siRNA in cancer therapy. We discuss several surface-functionalized MSNs' advancements as effective siRNA delivery vehicles in this paper. The advantages of using MSNs for siRNA loading regarding considerations of different shapes, various options for surface functionalization, and customizable pore sizes are highlighted. We discuss the recent investigations into strategies that efficiently improve cellular uptake, facilitate endosomal escape, and promote cargo dissociation from the MSNs for enhanced intracellular siRNA delivery. Also, particular attention was paid to the exciting progress made by combining RNAi with other therapies to improve cancer therapeutic outcomes.

RNAi therapies: Expanding applications for extrahepatic diseases and overcoming delivery challenges

The era of RNA medicine has become a reality with the success of messenger RNA (mRNA) vaccines against COVID-19 and the approval of several RNA interference (RNAi) agents in recent years. Particularly, therapeutics based on RNAi offer the promise of targeting intractable and previously undruggable disease genes. Recent advances have focused in developing delivery systems to enhance the poor cellular uptake and insufficient pharmacokinetic properties of RNAi therapeutics and thereby improve its efficacy and safety. However, such approach has been mainly achieved via lipid nanoparticles (LNPs) or chemical conjugation with N-Acetylgalactosamine (GalNAc), thus current RNAi therapy has been limited to liver diseases, most likely to encounter liver-targeting limitations. Hence, there is a huge unmet medical need for intense evolution of RNAi therapeutics delivery systems to target extrahepatic tissues and ultimately extend their indications for treating various intractable diseases. In this review, challenges of delivering RNAi therapeutics to tumors and major organs are discussed, as well as their transition to clinical trials. This review also highlights innovative and promising preclinical RNAi-based delivery platforms for the treatment of extrahepatic diseases.

Mesoporous Silica Nanoparticles as a Gene Delivery Platform for Cancer Therapy

Cancer remains a major global health challenge. Traditional chemotherapy often results in side effects and drug resistance, necessitating the development of alternative treatment strategies such as gene therapy. Mesoporous silica nanoparticles (MSNs) offer many advantages as a gene delivery carrier, including high loading capacity, controlled drug release, and easy surface functionalization. MSNs are biodegradable and biocompatible, making them promising candidates for drug delivery applications. Recent studies demonstrating the use of MSNs for the delivery of therapeutic nucleic acids to cancer cells have been reviewed, along with their potential as a tool for cancer therapy. The major challenges and future interventions of MSNs as gene delivery carriers for cancer therapy are discussed.

Simultaneous nanocarrier-mediated delivery of siRNAs and chemotherapeutic agents in cancer therapy and diagnosis: Recent advances

Recently, investigations have revealed that RNA interference (RNAi) has a remarkable potential to decrease cancer burden by downregulating genes. Among various RNAi molecules, small interfering RNA (siRNA) has been more attractive for this goal and is able to silence a target pathological path and promote the degradation of a certain mRNA, resulting in either gain or loss of function of proteins. Moreover, therapeutic siRNAs have exhibited low side effects compared to other therapeutic molecular candidates. Nevertheless, siRNA delivery has its own limitations including quick degradation in circulation, ineffective internalization and low passive uptake by cells, possible toxicity against off-target sites, and inducing unfavorable immune responses. Therefore, delivery tools must be able to specifically direct siRNAs to their target locations without inflicting detrimental effects on other sites. To conquer the mentioned problems, nanocarrier-mediated delivery of siRNAs, using inorganic nanoparticles (NPs), polymers, and lipids, has been developed as a biocompatible delivery approach. In this review, we have discussed recent advances in the siRNA delivery methods that employ nanoparticles, lipids, and polymers, as well as the inorganic-based co-delivery systems used to deliver siRNAs and anticancer agents to target cells.

An Efficient Carbon-Based Drug Delivery System for Cancer Therapy through the Nucleus Targeting and Mitochondria Mediated Apoptotic Pathway

The emergence of nanocarriers solves the problems of antitumor drugs such as non-targeting, huge side effects, etc., and has been widely used in tumor therapy. Some kinds of antitumor drugs such as doxorubicin (DOX) mainly act on the nucleic acid causing DNA damage, interfering with transcription, and thereby disrupting or blocking the process of cancer cell replication. Herein, a new nanodrug delivery system, the carbon-based nanomaterials (CBNs)-Pluronic F127-DOX (CPD), is designed by using CBNs as a nanocarrier for DOX. As a result, the tumor growth inhibition rate of CPD group is as high as 79.42 ± 2.83%, and greatly reduces the side effects. The targeting rate of the CPD group of DOX in the tumor nucleus is 36.78%, and the %ID/g in tumor tissue is 30.09%. The CPD regulates the expression levels of Caspase-3, p53, and Bcl-2 genes by increasing intracellular reactive oxygen species (ROS) levels and reducing mitochondrial membrane potential, which indicates that mitochondrial-mediated pathways are involved in apoptosis. The CPD nanodrug delivery system increases the effective accumulation of DOX in tumor cell nuclei and tumor tissues, and generates massive ROS, thereby inhibiting tumor growth in vivo, representing a promising agent for anticancer applications.

Surface functionalization of boron nitride nanosheet with folic acid: Toward an enhancement in Doxorubicin anticancer drug loading performance

Loading of the Doxorubicin (DOX) as an anticancer drug molecule on boron nitride (BN) nanosheets with different sizes, in the presence and absence of Folic Acid (FA) functional groups, are investigated using molecular dynamic simulations. The obtained results from these investigations revealed that the drug molecules are spontaneously adsorbed the carriers and form stable complexes. It is also shown that an increase the nanosheet leads to an enhancement in its capacity to adsorb the drugs. Furthermore, the conjugation of BN with the FA group not only improves the BN efficiency for the drug adsorption but also helps the drug-carrier complex to target the cancerous cells. Evaluation of interaction energies reveals that L-J interaction plays an essential role in the adsorption of the drug molecules on the BN. The radial distribution function (RDF) shows that the highest drug position probability is around 0.6 nm away from the BN surface. Atomic RDF analysis is in line with the interaction energy analysis and proved that π-π stacking contributes the most to this process. Hydrogen bond (HB) analysis also shows that, although limited, the columbic interaction can be helpful in the adsorption process. Moreover, the free energy (FE) surface is explored for a system containing a BN nanosheet, an FA group, and a DOX molecule through metadynamics simulations. The obtained results reveal that the lowest FE point located in coordinations d1 = 0.70 nm and d2 = 0.84 nm, and energetically reached -280.42 kJ/mol. It can be concluded from the FE calculations that while the FA is stuck on the substrate, DOX faces difficulty in the way it be adsorbed. In return, it will be hard for the molecule to be released from the BN surface through desorption processes in neutral pH because it faces an energy barrier with a height of ∼100 kJ/mol at 1.6 nm.

Delivery of small interfering RNAs by nanovesicles for cancer therapy

Small interfering ribonucleic acids (siRNAs) are originally recognized as an intermediate of the RNA interference (RNAi) pathway. They can inhibit or silence various cellular pathways by knocking down specific messenger RNA molecules. In cancer cells, siRNAs can suppress the expression of several multidrug-resistant genes, leading to the increased deposition of chemotherapeutic drugs at the tumor site. siRNA therapy can be used to selectively increase apoptosis of cancer cells or activate an immune response to the cancer. However, delivering siRNAs to the targeted location is the main limitation in achieving safe and effective delivery of siRNAs. This review highlights some representative examples of nonviral delivery systems, especially nanovesicles such as exosomes, liposomes, and niosomes. Nanovesicles can improve the delivery of siRNAs by increasing their intracellular delivery, and they have demonstrated excellent potential for cancer therapy. This review focuses on recent discoveries of siRNA targets for cancer therapy and the use of siRNAs to successfully silence these targets. In addition, this review summarizes the recent progress in designing nanovesicles (liposomes or niosomes) for siRNA delivery to cancer cells and the effects of a combination of anticancer drugs and siRNA therapy in cancer therapy.

siRNA delivery using intelligent chitosan-capped mesoporous silica nanoparticles for overcoming multidrug resistance in malignant carcinoma cells

Although siRNA is a promising technology for cancer gene therapy, effective cytoplasmic delivery has remained a significant challenge. In this paper, a potent siRNA transfer system with active targeting moieties toward cancer cells and a high loading capacity is introduced to inhibit drug resistance. Mesoporous silica nanoparticles are of great potential for developing targeted gene delivery. Amino-modified MSNs (NH₂-MSNs) were synthesized using a modified sol–gel method and characterized by FTIR, BET, TEM, SEM, X-ray diffraction, DLS, and ¹H-NMR. MDR1-siRNA was loaded within NH₂-MSNs, and the resulting negative surface was capped by functionalized chitosan as a protective layer. Targeting moieties such as TAT and folate were anchored to chitosan via PEG-spacers. The loading capacity of siRNA and the protective effect of chitosan for siRNA were determined by gel retardation assay. MTT assay, flow cytometry, real-time PCR, and western blot were performed to study the cytotoxicity, cellular uptake assay, targeting evaluation, and MDR1 knockdown efficiency. The synthesized NH₂-MSNs had a particle size of ≈ 100 nm and pore size of ≈ 5 nm. siRNA was loaded into NH₂-MSNs with a high loading capacity of 20% w/w. Chitosan coating on the surface of siRNA-NH₂-MSNs significantly improved the siRNA protection against enzyme activity compared to naked siRNA-NH₂-MSNs. MSNs and modified MSNs did not exhibit significant cytotoxicity at therapeutic concentrations in the EPG85.257-RDB and HeLa-RDB lines. The folate-conjugated nanoparticles showed a cellular uptake of around two times higher in folate receptor-rich HeLa-RDB than EPG85.257-RDB cells. The chitosan-coated siRNA-NH2-MSNs produced decreased MDR1 transcript and protein levels in HeLa-RDB by 0.20 and 0.48-fold, respectively. The results demonstrated that functionalized chitosan-coated siRNA-MSNs could be a promising carrier for targeted cancer therapy. Folate-targeted nanoparticles were specifically harvested by folate receptor-rich HeLa-RDB and produced a chemosensitized phenotype of the multidrug-resistant cancer cells.

Nanoformulations of Ursolic Acid: A Modern Natural Anticancer Molecule

Background: Ursolic acid (UA) is a natural pentacyclic triterpene derived from fruit, herb, and other plants. UA can act on molecular targets of various signaling pathways, inhibit the growth of cancer cells, promote cycle stagnation, and induce apoptosis, thereby exerting anticancer activity. However, its poor water-solubility, low intestinal mucosal absorption, and low bioavailability restrict its clinical application. In order to overcome these deficiencies, nanotechnology, has been applied to the pharmacological study of UA.

Objective: In this review, we focused on the absorption, distribution, and elimination pharmacokinetics of UA in vivo, as well as on the research progress in various UA nanoformulations, in the hope of providing reference information for the research on the anticancer activity of UA.

Methods: Relevant research articles on Pubmed and Web of Science in recent years were searched selectively by using the keywords and subheadings, and were summarized systematically.

Key finding: The improvement of the antitumor ability of the UA nanoformulations is mainly due to the improvement of the bioavailability and the enhancement of the targeting ability of the UA molecules. UA nanoformulations can even be combined with computational imaging technology for monitoring or diagnosis.

Conclusion: Currently, a variety of UA nanoformulations, such as micelles, liposomes, and nanoparticles, which can increase the solubility and bioactivity of UA, while promoting the accumulation of UA in tumor tissues, have been prepared. Although the research of UA in the nanofield has made great progress, there is still a long way to go before the clinical application of UA nanoformulations.

A smart dual-drug nanosystem based on co-assembly of plant and food-derived natural products for synergistic HCC immunotherapy

Nanotechnology has emerged as an ideal approach for achieving the efficient chemo agent delivery. However, the potential toxicity and unclear internal metabolism of most nano-carriers was still a major obstacle for the clinical application. Herein, a novel “core‒shell” co-assembly carrier-free nanosystem was constructed based on natural sources of ursolic acid (UA) and polyphenol (EGCG) with the EpCAM-aptamer modification for hepatocellular carcinoma (HCC) synergistic treatment. As the nature products derived from food-plant, UA and EGCG had good anticancer activities and low toxicity. With the simple and “green” method, the nanodrugs had the advantages of good stability, pH-responsive and strong penetration of tumor tissues, which was expected to increase tumor cellular uptake, long circulation and effectively avoid the potential defects of traditional carriers. The nanocomplex exhibited the low cytotoxicity in the normal cells in vitro, good biosafety of organic tissues and efficient tumor accumulation in vivo. Importantly, UA combined with EGCG showed the immunotherapy by activating the innate immunity and acquired immunity resulting in significant synergistic therapeutic effect. The research could provide new ideas for the research and development of self-assembly delivery system in the future, and offer effective intervention strategies for clinical HCC treatment.

Preparation and Applications of Organo-Silica Hybrid Mesoporous Silica Nanoparticles for the Co-Delivery of Drugs and Nucleic Acids

Combination therapies rely on the administration of more than one drug, with independent mechanisms of action, aiming to enhance the efficiency of the treatment. For an optimal performance, the implementation of such therapies requires the delivery of the correct combination of drugs to a specific cellular target. In this context, the use of nanoparticles (NP) as platforms for the co-delivery of multiple drugs is considered a highly promising strategy. In particular, mesoporous silica nanoparticles (MSN) have emerged as versatile building blocks to devise complex drug delivery systems (DDS). This review describes the design, synthesis, and application of MSNs to the delivery of multiple drugs including nucleic acids for combination therapies.

Advances and perspectives in carrier-free nanodrugs for cancer chemo-monotherapy and combination therapy

Nanocarrier-based drug delivery systems hold impressive promise for biomedical application because of their excellent water dispersibility, prolonged blood circulation time, increased drug accumulation in tumors, and potential in combination therapeutics. However, most nanocarriers suffer from low drug-loading efficiency, poor therapeutic effectiveness, potential systematic toxicity, and unstable metabolism. As an alternative, carrier-free nanodrugs, completely formulated with one or more drugs, have attracted increasing attention in cancer therapy due to their advantage of improved pharmacodynamics/pharmacokinetics, reduced toxicity, and high drug-loading. In recent years, carrier-free nanodrugs have contributed to progress in a variety of therapeutic modalities. In this review, different common strategies for carrier-free nanodrugs preparation are first summarized, mainly including nanoprecipitation, template-assisted nanoprecipitation, thin-film hydration, spray-drying technique, supercritical fluid (SCF) technique, and wet media milling. Then we describe the recently reported carrier-free nanodrugs for cancer chemo-monotherapy or combination therapy. The advantages of anti-cancer drugs combined with other chemotherapeutic, photosensitizers, photothermal, immunotherapeutic or gene drugs have been demonstrated. Finally, a future perspective is introduced to highlight the existing challenges and possible solutions toward clinical application of currently developed carrier-free nanodrugs, which may be instructive to the design of effective carrier-free regimens in the future.

Molecular insights and novel approaches for targeting tumor metastasis

In recent years, due to the effective drug delivery and preciseness of tumor sites or microenvironment, the targeted drug delivery approaches have gained ample attention for tumor metastasis therapy. The conventional treatment approaches for metastasis therapy have reported with immense adverse effects because they exhibited maximum probability of killing the carcinogenic cells along with healthy cells. The tumor vasculature, comprising of vasculogenic impressions and angiogenesis, greatly depends upon the growth and metastasis in the tumors. Therefore, various nanocarriers-based delivery approaches for targeting to tumor vasculature have been attempted as efficient and potential approaches for the treatment of tumor metastasis and the associated lesions. Furthermore, the targeted drug delivery approaches have found to be most apt way to overcome from all the limitations and adverse effects associated with the conventional therapies. In this review, various approaches for efficient targeting of pharmacologically active chemotherapeutics against tumor metastasis with the cohesive objectives of prognosis, tracking and therapy are summarized.

Multimodal Decorations of Mesoporous Silica Nanoparticles for Improved Cancer Therapy

The presence of leaky vasculature and the lack of lymphatic drainage of small structures by the solid tumors formulate nanoparticles as promising delivery vehicles in cancer therapy. In particular, among various nanoparticles, the mesoporous silica nanoparticles (MSN) exhibit numerous outstanding features, including mechanical thermal and chemical stability, huge surface area and ordered porous interior to store different anti-cancer therapeutics with high loading capacity and tunable release mechanisms. Furthermore, one can easily decorate the surface of MSN by attaching ligands for active targeting specifically to the cancer region exploiting overexpressed receptors. The controlled release of drugs to the disease site without any leakage to healthy tissues can be achieved by employing environment responsive gatekeepers for the end-capping of MSN. To achieve precise cancer chemotherapy, the most desired delivery system should possess high loading efficiency, site-specificity and capacity of controlled release. In this review we will focus on multimodal decorations of MSN, which is the most demanding ongoing approach related to MSN application in cancer therapy. Herein, we will report about the recently tried efforts for multimodal modifications of MSN, exploiting both the active targeting and stimuli responsive behavior simultaneously, along with individual targeted delivery and stimuli responsive cancer therapy using MSN.

Mesoporous Silica Nanoparticles for Co-Delivery of Drugs and Nucleic Acids in Oncology: A Review

Mesoporous silica nanoparticles have attracted much attention in recent years as drug and gene delivery systems for biomedical applications. Among their most beneficial features for biomedicine, we can highlight their biocompatibility and their outstanding textural properties, which provide a great loading capacity for many types of cargos. In the context of cancer nanomedicine, combination therapy and gene transfection/silencing have recently been highlighted as two of its most promising fields. In this review, we aim to provide an overview of the different small molecule drug-nucleic acid co-delivery combinations that have been developed using mesoporous silica nanoparticles as carriers. By carefully selecting the chemotherapeutic drug and nucleic acid cargos to be co-delivered by mesoporous silica nanoparticles, different therapeutic goals can be achieved by overcoming resistance mechanisms, combining different cytotoxic mechanisms, or providing an additional antiangiogenic effect. The examples here presented highlight the great promise of this type of strategies for the development of future therapeutics.

Mesoporous Silica Nanoparticles as Carriers for Therapeutic Biomolecules

The enormous versatility of mesoporous silica nanoparticles permits the creation of a large number of nanotherapeutic systems for the treatment of cancer and many other pathologies. In addition to the controlled release of small drugs, these materials allow a broad number of molecules of a very different nature and sizes. In this review, we focus on biogenic species with therapeutic abilities (proteins, peptides, nucleic acids, and glycans), as well as how nanotechnology, in particular silica-based materials, can help in establishing new and more efficient routes for their administration. Indeed, since the applicability of those combinations of mesoporous silica with bio(macro)molecules goes beyond cancer treatment, we address a classification based on the type of therapeutic action. Likewise, as illustrative content, we highlight the most typical issues and problems found in the preparation of those hybrid nanotherapeutic materials.

Codelivery of DOX and siRNA by folate-biotin-quaternized starch nanoparticles for promoting synergistic suppression of human lung cancer cells

In this paper, the self-assembled folate-biotin-quaternized starch nanoparticles (FBqS NPs) were used as carrier system of doxorubicin (DOX) and siRNAIGF1R for the codelivery of both into human lung adenocarcinoma cell lines (A549 cells) in vitro. The cytotoxicity, targeted ligand competition, cell proliferation inhibition, cellular uptake, endocytosis mechanism and target protein suppression of drug-loaded FBqS NPs were evaluated in detail. Compared with several other drug formulations under same condition, siRNAIGF1R/DOX/FBqS NPs exhibited the greatest cytotoxicity to A549 cells and the cytotoxicity was competitively inhibited by free folate in dose-dependent manner. The A549 cells treated by siRNAIGF1R/DOX/FBqS NPs showed the lowest cell proliferation capacity. The energy-dependent clathrin- and caveolae-mediated endocytosis might be the primary cellular uptake mechanism of drug-loaded FBqS NPs. The expression of IGF1R protein in A549 cells treated by siRNAIGF1R/FBqS NPs declined dramatically. So the FBqS NPs were expected as the co-carrier system of chemotherapeutants and siRNAs for future clinical application.

Amphiphilic Peptides for Efficient siRNA Delivery

A number of amphiphilic cyclic peptides-[FR]4, [WR]5, and [WK]5-containing hydrophobic and positively-charged amino acids were synthesized by Fmoc/tBu solid-phase peptide methods and evaluated for their efficiency in intracellular delivery of siRNA to triple-negative breast cancer cell lines, MDA-MB-231 and MDA-MB-468, in the presence and absence of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). Among the peptides, [WR]5, which contains alternate tryptophan (W) and arginine (R) residues, was found to be the most efficient in the delivery of siRNA by improving the delivery by more than 3-fold when compared to other synthesized cyclic peptides that were not efficient. The data also showed that co-formulation of [WR]5 with lipid DOPE significantly enhanced the efficiency of siRNA delivery by up to ~2-fold compared to peptide alone. Based on the data indicating the efficiency of [WR]5 in siRNA delivery, peptides containing arginine residues on the ring and tryptophan residues on the side chain, [R6K]W6 and [R5K]W5, were also evaluated, and demonstrated improved delivery of siRNA. The presence of DOPE again enhanced the siRNA delivery in most cases. [WR]5, [R5K]W5, and [R6K]W6 did not show any significant toxicity in MDA-MB-231, MDA-MB-468, and AU565 WT cells at N/P ratios of 20:1 or less, in the presence and absence of DOPE. Silencing of kinesin spindle protein (KSP) and Janus kinase 2 (JAK2) was evaluated in MDA-MB-231 cells in the presence of the peptides. The addition of DOPE significantly enhanced the silencing efficiency for all selected peptides. In conclusion, peptides containing tryptophan and arginine residues were found to enhance siRNA delivery and to generate silencing of targeted proteins in the presence of DOPE.

Targeted polyethylenimine/(p53 plasmid) nanocomplexes for potential antitumor applications

The development of the tumor-targeting ability of nanocarriers is of paramount importance for gene delivery into tumor lesions as well as to avoid biotoxicity. Here we report the synthesis of the polyethyleneimine-fluorescein isothiocyanate-folic acid (PEI-FITC-FA) polymer, which could condense the tumor suppressor pp53 to form nanocomplexes. These targeted nanocomplexes exhibited favorable physical properties including a small size of <100 nm, exploiting the enhanced permeability and retention effect and tumor-targeting ability by binding to the overexpressed FA receptors on tumor cell surfaces. In addition, once the nanocomplexes are accumulating in the tumor tissue, the target functional ligand, FA, can selectively recognize the over-expressed FA receptor and subsequently remain on the tumor cell surface, which can significantly promote the tumor cell uptake because of the time- and concentration-dependent internalization caused by the enhanced interaction between nanocomplex and tumor cell. Our results indicated that PEI-FITC-FA/pp53 nanocomplexes could be efficiently delivered into tumor cells, and subsequently induce tumor cell apoptosis. Thus, the targeted cationic polymer PEI-FITC-FA could be used as an advanced nanocarrier for gene delivery.

Ursolic Acid in Cancer Treatment and Metastatic Chemoprevention: From Synthesized Derivatives to Nanoformulations in Preclinical Studies

BACKGROUND

Cancer metastasis has emerged as a major public health threat that causes majority of cancer fatalities. Traditional chemotherapeutics have been effective in the past but suffer from low therapeutic efficiency and harmful side-effects. Recently, it has been reported ursolic acid (UA), one of the naturally abundant pentacyclic triterpenes, possesses a wide range of biological activities including anti-inflammatory, anti-atherosclerotic, and anti-cancer properties. More importantly, UA has the features of low toxicity, liver protection and the potential of anti-cancer metastasis.

OBJECTIVE

This article aimed at reviewing the great potential of UA used as a candidate drug in the field of cancer therapy relating to suppression of tumor initiation, progression and metastasis.

METHODS

Selective searches were conducted in Pubmed, Google Scholar and Web of Science using the keywords and subheadings from database inception to December 2017. Systemic reviews are summarized here.

RESULTS

UA has exhibited chemopreventive and therapeutic effects of cancer mainly through inducing apoptosis, inhibiting cell proliferation, preventing tumor angiogenesis and metastatic. UA nanoformulations could enhance the solubility and bioavailability of UA as well as exhibit better inhibitory effect on tumor growth and metastasis.

CONCLUSION

The information presented in this article can provide useful references for further studies on making UA a promising anti-cancer drug, especially as a prophylactic metastatic agent for clinical applications.

Implication of nano-antioxidant therapy for treatment of hepatocellular carcinoma using PLGA nanoparticles of rutin

Aim: The present work describes the development of poly(lactic co-glycolic acid) (PLGA) nanoparticles (NPs) of rutin (RT) for the treatment of hepatocellular carcinoma in rats. Materials & methods: RT-loaded PLGA NPs (RT-PLGA-NPs) were prepared by double emulsion evaporation method. Further these are optimized by Box–Behnken design. PLGA NPs were evaluated for size, polydispersity index, drug-loading capacity, entrapment, gastric stability, in vitro drug release, in vivo preclinical studies and biochemical studies. Results: Preclinical evaluation of RT-PLGA-NPs for anticancer activity through oral route exhibited significant improvement in hepatic, hematologic and renal biochemical parameters. Highly superior activity was observed in regulating oxidative stress and inflammatory markers, antioxidant enzymes, cytokines and inflammatory mediators and their role on plasma membrane ATPases responsible for destruction in liver tissues. Conclusion: Histopathological evaluation indicated reduced incidence of hepatic nodules, necrosis formation, infiltration of inflammatory cells, blood vessel inflammation and cell swelling with RT-PLGA-NP treatment along with considerable downregulation in the levels of proinflammatory cytokines.

A Small Molecule Nanodrug by Self-Assembly of Dual Anticancer Drugs and Photosensitizer for Synergistic near-Infrared Cancer Theranostics

Phototherapy including photodynamic therapy (PDT) and photothermal therapy (PTT) has attracted great attention. However, applications of some photosensitizers remain an obstacle by their poor photostability. To enhance the treatment efficiency of photosensitizers and tumor theranostic effect, herein, we reported a novel carrier-free, theranostic nanodrug by self-assembly of small molecule dual anticancer drugs and photosensitizer for tumor targeting. The developed carrier-free small molecule nanodrug delivery system was formed by hydrophobic ursolic acid, paclitaxel, and amphipathic indocyanine green (ICG) associated with electrostatic, π-π stacking, and hydrophobic interactions exhibiting water stability. The self-assembling of ICG on the dual anticancer nanodrug significantly enhanced water solubility of hydrophobic anticancer drugs and ICG photostability contributing to long-term near-infrared (NIR) fluorescence imaging and effective chemophototherapy of tumor. The in vivo NIR fluorescence imaging showed that the theranostic nanodrug could be targeted to the tumor site via a potential enhanced permeability and retention effect proving the efficient accumulation of nanoparticles in the tumor site. Dramatically, chemophototherapy of tumor-bearing mice in vivo almost completely suppressed tumor growth and no tumor recurrence was observed. Encouraged by its carrier-free, prominent imaging and effective therapy, the small molecule nanodrug via self-assembly will provide a promising strategy for synergistic cancer theranostics.

Synergistic Chemopreventive and Therapeutic Effects of Co-drug UA-Met: Implication in Tumor Metastasis

The anticancer properties of ursolic acid (UA) and metformin (Met) have been well demonstrated. However, whether these compounds can act synergistically to prevent and treat cancer is not known. We present in this study, the synergism between UA and Met, and that of a new codrug made of UA and Met (UA-Met) against several cancer cell lines. The combination of high concentration of UA (25, 50, 75, 100 μM) and Met (5, 10, 20, 40 mM) resulted in synergetic cytotoxicity on MDA-MB-231 and MCF-7 cells (CI < 0.8). Molecular and cellular studies showed that codrug UA-Met significantly inhibited the invasion (∼55.3 ± 2.74%) and migration (∼52.4 ± 1.57%) of TGF-β induced breast cancer MDA-MB-231 and MCF-7 cells in vitro at low concentration of 10 μM. These effects were accompanied by down-regulation of CXCR4, uPA, vimentin, E-cadherin, N-cadherin, and MMP-2/9 proteins expression and regulation of the AMPK/m-TOR signaling pathways as expected from UA and Met. Moreover, UA-Met could reduce the progression of pulmonary metastasis by 4T1 cells (63.4 ± 3.52%) without influencing the glucose blood level in mice. Our study suggests that the codrug UA-Met is safe and effective in preventing cancer metastasis and possibly treatment of cancer.

Difatty Acyl-Conjugated Linear and Cyclic Peptides for siRNA Delivery

A number of amphiphilic difatty acyl linear and cyclic R5K2 peptide conjugates were synthesized by solid-phase peptide methods to enhance the interaction with the hydrophobic cellular phospholipid bilayer and to improve siRNA delivery and silencing. Binding to siRNA molecules was significantly less for the cyclic peptide conjugates. A gradual decrease was observed in the particle size of the complexes with increasing peptide/siRNA ratio for most of the synthesized peptides, suggesting the complex formation. Most of the complexes showed a particle size of less than 200 nm, which is considered an appropriate size for in vitro siRNA delivery. A number of fatty acyl-conjugated peptides, such as LP-C16 and LP-C18, displayed near complete protection against serum degradation. Flow cytometry studies demonstrated significantly higher internalization of fluorescence-labeled siRNA (FAM-siRNA) in the presence of LP-C16, LP-C18, and CP-C16 with 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) addition. Confocal microscopy confirmed the cellular internalization of fluorescence-labeled siRNA in the presence of LP-C16 and LP-C18 with DOPE when compared with cells exposed to DOPE/FAM-siRNA. While C16- and C18-conjugated peptides (especially linear peptides) showed silencing against kinesin spindle protein (KSP) and janus kinase 2 (JAK2) proteins, the addition of DOPE enhanced the silencing efficiency significantly for all selected peptides, except for CP-C16. In conclusion, C16 and C18 difatty acyl peptide conjugates were found to enhance siRNA delivery and generate silencing of targeted proteins in the presence of DOPE. This study provides insights for the design and potential application of optimized difatty acyl peptide/lipid nanoparticles for effective siRNA delivery.