Stage-specific treatment of colorectal cancer: A microRNA-nanocomposite approach

Colorectal cancer (CRC) is among the leading causes of cancer mortality. The lifetime risk of developing CRC is about 5% in adult males and females. CRC is usually diagnosed at an advanced stage, and at this point therapy has a limited impact on cure rates and long-term survival. Novel and/or improved CRC therapeutic options are needed. The involvement of microRNAs (miRNAs) in cancer development has been reported, and their regulation in many oncogenic pathways suggests their potent tumor suppressor action. Although miRNAs provide a promising therapeutic approach for cancer, challenges such as biodegradation, specificity, stability and toxicity, impede their progression into clinical trials. Nanotechnology strategies offer diverse advantages for the use of miRNAs for CRC-targeted delivery and therapy. The merits of using nanocarriers for targeted delivery of miRNA-formulations are presented herein to highlight the role they can play in miRNA-based CRC therapy by targeting different stages of the disease.

Regulation and therapeutic potentials of microRNAs to non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer, accounting for 80%-85% of total cases and leading to millions of deaths worldwide. Drug resistance is the primary cause of treatment failure in NSCLC, which urges scientists to develop advanced approaches for NSCLC treatment. Among novel approaches, the miRNA-based method has emerged as a potential approach as it allows researchers to modulate target gene expression. Subsequently, cell behaviors are altered, which leads to the death and the depletion of cancer cells. It has been reported that miRNAs possess the capacity to regulate multiple genes that are involved in various signaling pathways, including the phosphoinositide 3-kinase, receptor tyrosine kinase/rat sarcoma virus/mitogen-activated protein kinase, wingless/integrated, retinoblastoma, p53, transforming growth factor β, and nuclear factor-kappa B pathways. Dysregulation of these signaling pathways in NSCLC results in abnormal cell proliferation, tissue invasion, and drug resistance while inhibiting apoptosis. Thus, understanding the roles of miRNAs in regulating these signaling pathways may enable the development of novel NSCLC treatment therapies. However, a comprehensive review of potential miRNAs in NSCLC treatment has been lacking. Therefore, this review aims to fill the gap by summarizing the up-to-date information on miRNAs regarding their targets, impact on cancer-associated pathways, and prospective outcomes in treating NSCLC. We also discuss current technologies for delivering miRNAs to the target cells, including virus-based, non-viral, and emerging extracellular vesicle-based delivery systems. This knowledge will support future studies to develop an innovative miRNA-based therapy and select a suitable carrier to treat NSCLC effectively.

Chondroitin sulfate-based composites: a tour d'horizon of their biomedical applications

Chondroitin sulfate (CS), a natural anionic mucopolysaccharide, belonging to the glycosaminoglycan family, acts as the primary element of the extracellular matrix (ECM) of diverse organisms. It comprises repeating units of disaccharides possessing β-1,3-linked N-acetyl galactosamine (GalNAc), and β-1,4-linked D-glucuronic acid (GlcA), and exhibits antitumor, anti-inflammatory, anti-coagulant, anti-oxidant, and anti-thrombogenic activities. It is a naturally acquired bio-macromolecule with beneficial properties, such as biocompatibility, biodegradability, and immensely low toxicity, making it the center of attention in developing biomaterials for various biomedical applications. The authors have discussed the structure, unique properties, and extraction source of CS in the initial section of this review. Further, the current investigations on applications of CS-based composites in various biomedical fields, focusing on delivering active pharmaceutical compounds, tissue engineering, and wound healing, are discussed critically. In addition, the manuscript throws light on preclinical and clinical studies associated with CS composites. A short section on Chondroitinase ABC has also been canvassed. Finally, this review emphasizes the current challenges and prospects of CS in various biomedical fields.

Delivery of miRNAs to the adipose organ for metabolic health

Despite the increasing prevalence of obesity and diabetes, there is no efficient treatment to combat these epidemics. The adipose organ is the main site for energy storage and plays a pivotal role in whole body lipid metabolism and energy homeostasis, including remodeling and dysfunction of adipocytes and adipose tissues in obesity and diabetes. Thus, restoring and balancing metabolic functions in the adipose organ is in demand. MiRNAs represent a novel class of drugs and drug targets, as they are heavily involved in the regulation of many cellular and metabolic processes and diseases, likewise in adipocytes. In this review, we summarize key regulatory activities of miRNAs in the adipose organ, discuss various miRNA replacement and inhibition strategies, promising delivery systems for miRNAs and reflect the future of novel miRNA-based therapeutics to target adipose tissues with the ultimate goal to combat metabolic disorders.

Host miRNA and immune cell interactions: relevance in nano-therapeutics for human health

Around 2200 miRNA (microRNA) genes were found in the human genome. miRNAs are arranged in clusters within the genome and share the same transcriptional regulatory units. It has been revealed that approximately 50% of miRNAs elucidated in the genome are transcribed from non-protein-coding genes, and the leftover miRNAs are present in the introns of coding sequences. We are now approaching a stage in which miRNA diagnostics and therapies can be established confidently, and several commercial efforts are underway to carry these innovations from the bench to the clinic. MiRNAs control many of the significant cellular activities such as production, differentiation, growth, and metabolism. Particularly in the immune system, miRNAs have emerged as a crucial biological component during diseased state and homeostasis. miRNAs have been found to regulate inflammatory responses and autoimmune disorders. Moreover, each miRNA targets multiple genes simultaneously, making miRNAs promising tools as diagnostic biomarkers and as remedial targets. Still, one of the major obstacles in miRNA-based approaches is the achievement of specific and efficient systemic delivery of miRNAs. To overcome these challenges, nanoformulations have been synthesized to protect miRNAs from degradation and enhance cellular uptake. The current review deals with the miRNA-mediated regulation of the recruitment and activation of immune cells, especially in the tumor microenvironment, viral infection, inflammation, and autoimmunity. The nano-based miRNA delivery modes are also discussed here, especially in the context of immune modulation.

Polymer nanocarriers for MicroRNA delivery

Abnormal expression of microRNAs (miRNAs), which are highlyconserved noncoding RNAs that regulate the expression of various genes post transcriptionally to control cellular functions, has been associated with the development of many diseases. In some cases, disease-promoting miRNAs are upregulated, while in other instances disease-suppressive miRNAs are downregulated. To alleviate this imbalanced miRNA expression, either antagomiRs or miRNA mimics can be delivered to cells to inhibit or promote miRNA expression, respectively. Unfortunately, the clinical translation of bare antagomiRs and miRNA mimics has been challenging because nucleic acids are susceptible to nuclease degradation, display unfavorable pharmacokinetics, and cannot passively enter cells. This review emphasizes the challenges associated with miRNA mimic delivery and then discusses the design and implementation of polymer nanocarriers to overcome these challenges. Preclinical efforts are summarized, and a forward-looking perspective on the future clinical translation of polymer nanomaterials as miRNA delivery vehicles is provided.

Aptamer Hybrid Nanocomplexes as Targeting Components for Antibiotic/Gene Delivery Systems and Diagnostics: A Review

With the passage of time and more advanced societies, there is a greater emergence and incidence of disease and necessity for improved treatments. In this respect, nowadays, aptamers, with their better efficiency at diagnosing and treating diseases than antibodies, are at the center of attention. Here, in this review, we first investigate aptamer function in various fields (such as the detection and remedy of pathogens, modification of nanoparticles, antibiotic delivery and gene delivery). Then, we present aptamer-conjugated nanocomplexes as the main and efficient factor in gene delivery. Finally, we focus on the targeted co-delivery of genes and drugs by nanocomplexes, as a new exciting approach for cancer treatment in the decades ahead to meet our growing societal needs.

Dendrimers Show Promise for siRNA and microRNA Therapeutics

The lack of an appropriate intracellular delivery system for therapeutic nucleic acids (TNAs) is a major problem in molecular biology, biotechnology, and medicine. A relatively new class of highly symmetrical hyperbranched polymers, called dendrimers, shows promise for transporting small TNAs into both cells and target tissues. Dendrimers have intrinsic advantages for this purpose: their physico-chemical and biological properties can be controlled during synthesis, and they are able to transport large numbers of TNA molecules that can specifically suppress the expression of single or multiple targeted genes. Numerous chemical modifications of dendrimers extend the biocompatibility of synthetic materials and allow targeted vectors to be designed for particular therapeutic purposes. This review summarizes the latest experimental data and trends in the medical application of various types of dendrimers and dendrimer-based nanoconstructions as delivery systems for short small interfering RNAs (siRNAs) and microRNAs at the cell and organism levels. It provides an overview of the structural features of dendrimers, indicating their advantages over other types of TNA transporters.

Self-sensibilized polymeric prodrug co-delivering MMP-9 shRNA plasmid for combined treatment of tumors

Polymeric prodrugs are of immense interest as anticancer drug-delivery system owing to their superior drug stability during circulation and satisfactory drug loading capacity. However, they are usually less effective than free drugs due to imperfect degradable characteristics or active sites blockage. A polymeric prodrug (HPAA-MTX) with chemotherapeutic self-sensibilization effect consisting of glutathione (GSH)-triggered hyperbranched poly(amido amine) (HPAA) and methotrexate (MTX) was designed and synthesized in this work. This prodrug not only showed better inhibition effect on the tumor cells proliferation compared with free MTX, but also displayed selective sensibilization to tumor cells rather than normal cells. Meanwhile, HPAA-MTX was also explored as a MMP-9 shRNA plasmid delivery vector due to their rich amino group of HPAA, accompanying with MTX for simultaneous inhibiting tumor cells proliferation and migration. As expected, HPAA-MTX possessed excellent gene delivery capacity with significant down-regulation expression of MMP-9 protein and further inhibition of MCF-7 cells migration. Benefiting from the self-sensibilization effect and MTX/MMP-9 co-delivery strategy, this HPAA-MTX/MMP-9 co-delivery system exhibited significantly improved therapeutic efficacy to breast cancer in a combined manner which was confirmed through in vitro and in vivo assays. The strategy established in this study provided a facile "all-in-one" platform to integrate the drug/gene co-delivery strategy and self-sensibilization effect into one single nanocomposite for potential cancer treatment.

STATEMENT OF SIGNIFICANCE

A cationic polymeric prodrug with chemotherapeutic self-sensibilization effect was designed and showed better inhibition effect on tumor cells proliferation compared with its free drug, as well displayed the selective sensibilization effect to tumor cells rather than normal cells. Moreover, the prodrug could also deliver MMP-9 shRNA plasmid for a combined therapy. As expected, the prodrug possessed excellent gene delivery capacity with significant down-regulation expression of MMP-9 protein and further inhibition of MCF-7 cells migration. Benefiting from the self-sensibilization effect and the drug/gene co-delivery strategy, this prodrug exhibited significantly improved therapeutic efficacy to breast cancer in a combined manner.

Chondroitin sulfate-functionalized polyamidoamine as a tumor-targeted carrier for miR-34a delivery

Chondroitin sulfate (CS) was modified on a polyamidoamine dendrimer (PAMAM) through Michael addition to construct a tumor-targeted carrier CS-PAMAM for miR-34a delivery. The derivative CS-PAMAM was demonstrated to achieve an efficient cellular uptake of miR-34a in a CD44-dependent endocytosis way and further facilitate the endosomal escape of miR-34a after 4h. Through the miR-34a delivery, obvious inhibition of cell proliferation could be detected which was attributed to the enhancement of cell apoptosis and cell cycle arrest, and meanwhile the cell migration and invasion has been observed to be inhibited. Finally, the intravenous injection of CS-PAMAM/miR-34a formulation into mice bearing human lung adenocarcinoma cell A549 xenografts could efficiently inhibit the tumor growth and induce the tumor apoptosis owing to the enhanced accumulation of miR-34a in tumor tissue. Overall, CS-PAMAM is potential to be used as a tumor-targeted oligonucleotide carrier for achieving tumor gene therapy.

STATEMENT OF SIGNIFICANCE

The cationic dendrimer PAMAM was modified by chondroitin sulfate (CS) through Michael addition to construct a tumor-targeted carrier CS-PAMAM for miR-34a delivery. The introduction of CS could achieve an efficient cellular uptake and intracellular transfection of miR-34a in a CD44-dependent endocytosis manner. The miR-34a delivery could execute the anti-proliferation activity by simultaneously inducing cell apoptosis and cell cycle arrest, and also the anti-migration activity. The CS-PAMAM-mediated systemic delivery of miR-34a showed significant inhibition of tumor growth and induction of tumor apoptosis using a mice model of subcutaneously implanted tumors.

An ATP-Responsive Codelivery System of Doxorubicin and MiR-34a To Synergistically Inhibit Cell Proliferation and Migration

Establishing stimulus-responsive nanosystems for the codelivery of anticancer drug and oligonucleotide is a promising strategy in cancer treatment owing to the combination of chemotherapy and gene therapy in a synergistic manner. Herein, an ATP aptamer and its cDNA sequence were first hybridized to produce the duplex, into which chemotherapeutic agent doxorubicin (DOX) interacted through the GC-rich motif of duplex, and PEI25K was then employed as a carrier to condense the DOX-loading duplex and miR-34a to construct the ternary nanocomplex PEI/DOX-Duplex/miR-34a. The nanocomplex exhibited a favorable drug release profile through the response to high concentration of ATP in the cytosol. The ATP-responsive delivery system was demonstrated to possess higher antiproliferative effect (cell viability of <40%) than the single cargo delivery, which could be attributed to the synergistic induction of cell apoptosis and cell cycle arrest from DOX and miR-34a. Furthermore, wound healing and Transwell assay elucidated the higher antimigration effect of ternary nanocomplex than DOX-Duplex or miR-34a delivery. Overall, the combinatorial delivery of DOX and miR-34a through an ATP-responsive manner could trigger the rapid release of cargoes in the cytosol and enhance the inhibition of cell proliferation and migration through the synergistic manner of these two components.