Enhanced combination cancer therapy using lipid-calcium carbonate/phosphate nanoparticles as a targeted delivery platform

Biomedical applications of nanomaterials in the advancement of nucleic acid therapy: Mechanistic challenges, delivery strategies, and therapeutic applications

In the past few decades, substantial advancement has been made in nucleic acid (NA)-based therapies. Promising treatments include mRNA, siRNA, miRNA, and anti-sense DNA for treating various clinical disorders by modifying the expression of DNA or RNA. However, their effectiveness is limited due to their concentrated negative charge, instability, large size, and host barriers, which make widespread application difficult. The effective delivery of these medicines requires safe vectors that are efficient & selective while having non-pathogenic qualities; thus, nanomaterials have become an attractive option with promising possibilities despite some potential setbacks. Nanomaterials possess ideal characteristics, allowing them to be tuned into functional bio-entity capable of targeted delivery. In this review, current breakthroughs in the non-viral strategy of delivering NAs are discussed with the goal of overcoming challenges that would otherwise be experienced by therapeutics. It offers insight into a wide variety of existing NA-based therapeutic modalities and techniques. In addition to this, it provides a rationale for the use of non-viral vectors and a variety of nanomaterials to accomplish efficient gene therapy. Further, it discusses the potential for biomedical application of nanomaterials-based gene therapy in various conditions, such as cancer therapy, tissue engineering, neurological disorders, and infections.

PD-L1-Targeted Co-Delivery of Two Chemotherapeutics for Efficient Suppression of Skin Cancer Growth

To overcome the severe side effects of cancer chemotherapy, it is vital to develop targeting chemotherapeutic delivery systems with the potent inhibition of tumour growth, angiogenesis, invasion and migration at low drug dosages. For this purpose, we co-loaded a conventional antiworm drug, albendazole (ABZ), and a TOPK inhibitor, OTS964, into lipid-coated calcium phosphate (LCP) nanoparticles for skin cancer treatment. OTS- and ABZ-loaded LCP (OTS-ABZ-LCP) showed a synergistic cytotoxicity against skin cancer cells through their specific cancerous pathways, without obvious toxicity to healthy cell lines. Moreover, dual-targeting the programmed death ligand-1 (PD-L1) and folate receptor overexpressed on the surface of skin cancer cells completely suppressed the skin tumour growth at low doses of ABZ and OTS. In summary, ABZ and OTS co-loaded dual-targeting LCP NPs represent a promising platform with high potentials against complicated cancers where PD-L1/FA dual targeting appears as an effective approach for efficient and selective cancer therapy.

Mineralized vectors for gene therapy

There is an intense interest in developing materials for safe and effective delivery of polynucleotides using non-viral vectors. Mineralization of organic templates has long been used to produce complex materials with outstanding biocompatibility. However, a lack of control over mineral growth has limited the applicability of mineralized materials to a few in vitro applications. With better control over mineral growth and surface functionalization, mineralized vectors have advanced significantly in recent years. Here, we review the recent progress in chemical synthesis, physicochemical properties, and applications of mineralized materials in gene therapy, focusing on structure-function relationships. We contrast the classical understanding of the mineralization mechanism with recent ideas of mineralization. A brief introduction to gene delivery is summarized, followed by a detailed survey of current mineralized vectors. The vectors derived from calcium phosphate are articulated and compared to other minerals with unique features. Advanced mineral vectors derived from templated mineralization and specialty coatings are critically analyzed. Mineral systems beyond the co-precipitation are explored as more complex multicomponent systems. Finally, we conclude with a perspective on the future of mineralized vectors by carefully demarcating the boundaries of our knowledge and highlighting ambiguous areas in mineralized vectors. STATEMENT OF SIGNIFICANCE: Therapy by gene-based medicines is increasingly utilized to cure diseases that are not alleviated by conventional drug therapy. Gene medicines, however, rely on macromolecular nucleic acids that are too large and too hydrophilic for cellular uptake. Without tailored materials, they are not functional for therapy. One emerging class of nucleic acid delivery system is mineral-based materials. The fact that they can undergo controlled dissolution with minimal footprint in biological systems are making them attractive for clinical use, where safety is utmost importance. In this submission, we will review the emerging synthesis technology and the range of new generation minerals for use in gene medicines.

Nanocarrier-based Drug Delivery System for Cancer Therapeutics: A Review of the Last Decade

In recent years, due to the shortcomings of conventional chemotherapy, such as poor bioavailability, low treatment index, and unclear side effects, the focus of cancer research has shifted to new nanocarriers of chemotherapeutic drugs. By using biodegradable materials, nanocarriers generally have the advantages of good biocompatibility, low side effects, targeting, controlled release profile, and improved efficacy. More to the point, nanocarrier based anti-cancer drug delivery systems clearly show the potential to overcome the problems associated with conventional chemotherapy. In order to promote the in-depth research and development in this field, we herein summarized and analyzed various nanocarrier based drug delivery systems for cancer therapy, including the concepts, types, characteristics, and preparation methods. The active and passive targeting mechanisms of cancer therapy were also included, along with a brief introduction of the research progress of nanocarriers used for anti-cancer drug delivery in the past decade.

A Review of pH-Responsive Organic-Inorganic Hybrid Nanoparticles for RNAi-Based Therapeutics

RNA interference (RNAi) shows great potential in the treatment of varying cancer and genetic disorders. The lack of safe and effective delivery methods is an ongoing challenge to realize the full potential of RNAi-based therapeutics. pH-responsive hybrid nanoparticle is a promising non-virus platform for small interfering RNA (siRNA) delivery with unique properties including the robust response to the acidic microenvironment and the capability of theranostic and combined therapeutics. The mechanism of RNAi and the delivery barriers for RNAi-based therapeutics are first discussed. Then, the general patterns of pH-response and the typical construction of hybrid nanoparticles are demonstrated. The recent advances in pH-responsive organic-inorganic hybrid nanoparticles for siRNA delivery are highlighted, in particular, how pH-response of ionizable groups, acid-labile bonds, and decomposition of inorganic components affect the physicochemical properties of hybrid nanoparticles and benefit the cellular uptake and intracellular trafficking of siRNA payloads are discussed. At last, the remaining problems and the prospects for pH-responsive hybrid nanoparticles for siRNA delivery are analyzed.

Vitamin E succinate with multiple functions: A versatile agent in nanomedicine-based cancer therapy and its delivery strategies

Vitamin E succinate (VES), a succinic acid ester of vitamin E, is one of the most effective anticancer compounds of the vitamin E family. VES can inhibit tumor growth by multiple pathways mainly involve tumor proliferation inhibition, apoptosis induction, and metastasis prevention. More importantly, the mitochondrial targeting and damaging property of VES endows it with great potential in exhibiting synergetic effect with conventional chemotherapeutic drugs and overcoming multidrug resistance (MDR). Given the lipophilicity of VES that hinders its bioavailability and therapeutic activity, nanotechnology with multiple advantages has been widely explored to deliver VES and opened up new avenues for its in vivo application. This review aims to introduce the anticancer mechanisms of VES and summarize its delivery strategies using nano-drug delivery systems. Specifically, VES-based combination therapy for synergetic anticancer effect, MDR-reversal, and oral chemotherapy improvement are highlighted. Finally, the challenges and perspectives are discussed.

Carbon Nanoparticles and Materials on Their Basis

Carbon nanoparticles (CNPs) are novel nanostructures with luminescent properties. The development of CNPs involves the elaboration of various synthetic methods, structure characterization, and different applications. However, the problems associated with the CNP structure definition and properties homogeneity are not solved and barely described in depth. In this feature article, we demonstrate the approaches for the effective separation and purification of CNPs by size and size/charge ratio. We propose a promising way for the synthesis of the uniform-size structures by the application of calcium carbonate porous microparticles as reactors with defined size. Additionally, the application of the CNPs agglomerates for controllable release systems triggered by light and in-situ synthesis of fluorescent conductive carbonaceous films on the base of polyelectrolyte multilayers are under consideration.

Charge Reversion Simultaneously Enhances Tumor Accumulation and Cell Uptake of Layered Double Hydroxide Nanohybrids for Effective Imaging and Therapy

Nanotheranostics have been actively sought in precision nanomedicine in recent years. However, insufficient tumor accumulation and limited cell uptake often impede the nanotheranostic efficacy. Herein, pH-sensitive charge-reversible polymer-coated layered double hydroxide (LDH) nanohybrids are devised to possess long circulation in blood but reserve surface charges in the weakly acidic tumor tissue to re-expose therapeutic LDH nanoparticles for enhanced tumor accumulation and cell uptake. In vitro experimental data demonstrate that charge-reversible nanohybrids mitigate the cell uptake in physiological conditions (pH 7.4), but remarkably facilitate internalization by tumor cells after charge reversion in the weakly acidic environment (pH 6.8). More significantly, about 6.0% of injected charge-reversible nanohybrids accumulate in the tumor tissue at 24 h post injection, far higher than the average accumulation (0.7%) reported elsewhere for nanoparticles. This high tumor accumulation clearly shows the tumor tissues in T₁ -weighted magnetic resonance imaging. As a consequence, >95% inhibition of tumor growth in the B16F0-bearing mouse model is achieved via only one treatment combining RNAi and photothermal therapy under very mild irradiation (808 nm laser, 0.3 W cm^-2 for 180 s). The current research thus demonstrates a new strategy to functionalize nanoparticles and simultaneously enhance their tumor accumulation and cell internalization for effective cancer theranostics.

Biodegradable calcium phosphate nanoparticles for cancer therapy

Calcium phosphate is the inorganic mineral of hard tissues such as bone and teeth. Due to their similarities to the natural bone, calcium phosphates are highly biocompatible and biodegradable materials that have found numerous applications in dental and orthopedic implants and bone tissue engineering. In the form of nanoparticles, calcium phosphate nanoparticles (CaP's) can also be used as effective delivery vehicles to transfer therapeutic agents such as nucleic acids, drugs, proteins and enzymes into tumor cells. In addition, facile preparation and functionalization of CaP's, together with their inherent properties such as pH-dependent solubility provide advantages in delivery and release of these bioactive agents using CaP's as nanocarriers. In this review, the challenges and achievements in the intracellular delivery of these agents to tumor cells are discussed. Also, the most important issues in the design and potential applications of CaP-based biominerals are addressed with more focus on their biodegradability in tumor microenvironment.

Enhanced Prevention of Breast Tumor Metastasis by Nanoparticle-Delivered Vitamin E in Combination with Interferon-Gamma

Preventing cancer metastasis is one of the remaining challenges in cancer therapy. As an efficient natural product, alpha-tocopheryl succinate (α-TOS), the most effective form of vitamin E, holds great anticancer potential. To improve its efficacy and bioavailability, lipid-coated calcium carbonate/phosphate (LCCP) nanoparticles (NPs) with folic acid and PEG modification are synthesized for efficient delivery of α-TOS to 4T1 cancer cells. The optimized LCCP-FA NPs (NP-TOS15) show an α-TOS loading efficiency of around 60%, and enhanced uptake by 4T1 metastatic cancer cells. Consequently, NP-TOS15 significantly enhance the anticancer effect in combination with interferon-gamma (IFN-γ) in terms of apoptosis facilitation and migration inhibition. Importantly, NP-TOS15 upregulate the anticancer immunity via downregulating program death ligand 1 (PD-L1) expression that is initially induced by IFN-γ, and remarkably prevent the lung metastasis, particularly in combination with IFN-γ. Further investigation reveals that this combination therapy also modulates the cytotoxic lymphocyte infiltration into the tumor microenvironment for tumor elimination. Taken together, the NP delivery of α-TOS in combination with IFN-γ provides an applicable strategy for cancer therapy.

Polymeric Co-Delivery Systems in Cancer Treatment: An Overview on Component Drugs' Dosage Ratio Effect

Multiple factors are involved in the development of cancers and their effects on survival rate. Many are related to chemo-resistance of tumor cells. Thus, treatment with a single therapeutic agent is often inadequate for successful cancer therapy. Ideally, combination therapy inhibits tumor growth through multiple pathways by enhancing the performance of each individual therapy, often resulting in a synergistic effect. Polymeric nanoparticles prepared from block co-polymers have been a popular platform for co-delivery of combinations of drugs associated with the multiple functional compartments within such nanoparticles. Various polymeric nanoparticles have been applied to achieve enhanced therapeutic efficacy in cancer therapy. However, reported drug ratios used in such systems often vary widely. Thus, the same combination of drugs may result in very different therapeutic outcomes. In this review, we investigated polymeric co-delivery systems used in cancer treatment and the drug combinations used in these systems for synergistic anti-cancer effect. Development of polymeric co-delivery systems for a maximized therapeutic effect requires a deeper understanding of the optimal ratio among therapeutic agents and the natural heterogenicity of tumors.