Creatine based polymer for codelivery of bioengineered MicroRNA and chemodrugs against breast cancer lung metastasis

Polymeric nanomaterials-based theranostic platforms for triple-negative breast cancer (TNBC) treatment

Breast cancer, the second leading global cause of death, affects 2.1 million women annually, with an alarming 15 percent mortality rate. Among its diverse forms, Triple-negative breast cancer (TNBC) emerges as the deadliest, characterized by the absence of hormone receptors. This article underscores the urgent need for innovative treatment approaches in tackling TNBC, emphasizing the transformative potential of polymeric nanomaterials (PNMs). Evolved through nanotechnology, PNMs offer versatile biomedical applications, particularly in addressing the intricate challenges of TNBC. The synthesis methods of PNMs, explored within the tumor microenvironment using cellular models, showcase their dynamic nature in cancer treatment. The article anticipates the future of TNBC therapeutics through the optimization of PNMs-based strategies, integrating them into photothermal (PT), photodynamic (PT), and hyperthermia therapy (HTT), drug delivery, and active tumor targeting strategies. Advancements in synthetic methods, coupled with a nuanced understanding of the tumor microenvironment, hold promise for personalized interventions. Comparative investigations of therapeutic models and a thorough exploration of polymeric nanoplatforms toxicological perspectives become imperative for ensuring efficacy and safety. We have explored the interdisciplinary collaboration between nanotechnology, oncology, and molecular biology as pivotal in translating PNMs innovations into tangible benefits for TNBC patients.

Mapping the function of MicroRNAs as a critical regulator of tumor-immune cell communication in breast cancer and potential treatment strategies

Among women, breast cancer ranks as the most prevalent form of cancer, and the presence of metastases significantly reduces prognosis and diminishes overall survival rates. Gaining insights into the biological mechanisms governing the conversion of cancer cells, their subsequent spread to other areas of the body, and the immune system's monitoring of tumor growth will contribute to the advancement of more efficient and targeted therapies. MicroRNAs (miRNAs) play a critical role in the interaction between tumor cells and immune cells, facilitating tumor cells' evasion of the immune system and promoting cancer progression. Additionally, miRNAs also influence metastasis formation, including the establishment of metastatic sites and the transformation of tumor cells into migratory phenotypes. Specifically, dysregulated expression of these genes has been associated with abnormal expression of oncogenes and tumor suppressor genes, thereby facilitating tumor development. This study aims to provide a concise overview of the significance and function of miRNAs in breast cancer, focusing on their involvement as tumor suppressors in the antitumor immune response and as oncogenes in metastasis formation. Furthermore, miRNAs hold tremendous potential as targets for gene therapy due to their ability to modulate specific pathways that can either promote or suppress carcinogenesis. This perspective highlights the latest strategies developed for miRNA-based therapies.

Genetic variations in tumor-suppressor miRNA-encoding genes and their target genes: focus on breast cancer development and possible therapeutic strategies

MicroRNAs (miRNAs) negatively affect gene expression by binding to their specific mRNAs resulting in either mRNA destruction or translational repression. The aberrant expression of various miRNAs has been associated with a number of human cancer. Oncogenic or tumor-suppressor miRNAs regulate a variety of pathways involved in the development of breast cancer (BC), including cell proliferation, apoptosis, metastasis, cancer recurrence, and chemoresistance. Variations in miRNA-encoding genes and their target genes lead to dysregulated gene expression resulting in the development and progression of BC. The various therapeutic approaches to treat the disease include chemotherapy, radiation therapy, surgical removal, hormone therapy, chemotherapy, and targeted biological therapy. The purpose of the current review is to explore the genetic variations in tumor-suppressor miRNA-encoding genes and their target genes in association with the disease development and prognosis. The therapeutic interventions targeting the variants for better disease outcomes have also been discussed.

Bioengineered chimeric tRNA/pre-miRNAs as prodrugs in cancer therapy

Today, biologic prodrugs have led to targeting specific tumor markers and have increased specificity and selectivity in cancer therapy. Various studies have shown the role of ncRNAs in cancer pathology and tumorigenesis and have suggested that ncRNAs, especially miRNAs, are valuable molecules in understanding cancer biology and therapeutic processes. Most miRNAs-based research and treatment are limited to chemically synthesized miRNAs. Synthetic alterations in these miRNA mimics may affect their folding, safety profile, and even biological activity. However, despite synthetic miRNA mimics produced by automated systems, various carriers could be used to achieve efficient production of bioengineered miRNAs through economical microbial fermentation. These bioengineered miRNAs as biological prodrugs could provide a new approach for safe therapeutic methods and drug production. In this regard, bioengineered chimeric miRNAs could be selectively processed to mature miRNAs in different types of cancer cells by targeting the desired gene and regulating cancer progression. In this article, we aim to review bioengineered miRNAs and their use in cancer therapy, as well as offering advances in this area, including the use of chimeric tRNA/pre-miRNAs.

Impact of Nanomedicine in Women's Metastatic Breast Cancer

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

Metastatic Breast Cancer: Review of Emerging Nanotherapeutics

Metastases of breast cancer (BC) are often referred to as stage IV breast cancer due to their severity and high rate of mortality. The median survival time of patients with metastatic BC is reduced to 3 years. Currently, the treatment regimens for metastatic BC are similar to the primary cancer therapeutics and are limited to conventional chemotherapy, immunotherapy, radiotherapy, and surgery. However, metastatic BC shows organ-specific complex tumor cell heterogeneity, plasticity, and a distinct tumor microenvironment, leading to therapeutic failure. This issue can be successfully addressed by combining current cancer therapies with nanotechnology. The applications of nanotherapeutics for both primary and metastatic BC treatments are developing rapidly, and new ideas and technologies are being discovered. Several recent reviews covered the advancement of nanotherapeutics for primary BC, while also discussing certain aspects of treatments for metastatic BC. This review provides comprehensive details on the recent advancement and future prospects of nanotherapeutics designed for metastatic BC treatment, in the context of the pathological state of the disease. Furthermore, possible combinations of current treatment with nanotechnology are discussed, and their potential for future transitions in clinical settings is explored.

IKKα inhibition re-sensitizes acquired adriamycin-resistant triple negative breast cancer cells to chemotherapy-induced apoptosis

IKKα has been shown to be responsible of multiple pro-tumorigenic functions and therapy resistance independent of canonical NF-κB, but its role in acquired chemotherapy resistance in breast cancer remains unclarified. In this study, we obtained pre-treatment biopsy and post-treatment mastectomy specimens from a retrospective cohort of triple-negative breast cancer (TNBC) patients treated with neoadjuvant chemotherapy(NAC) (n = 43). Immunohistochemical methods were used to detect the expression of IKKα before and after NAC, and the relationship between IKKα and the pathologic response to NAC was examined. In addition, we developed a new ADR-resistant MDA-MB-231 cell line(MDA-MB-231/ADR) and analyzed these cells for changes in IKKα expression, the role and mechanisms of the increased IKKα in promoting drug resistance were determined in vitro and in vivo. We demonstrated that the expression of IKKα in residual TNBC tissues after chemotherapy was significantly higher than that before chemotherapy, and was positively correlated with lower pathological reaction. IKKα expression was significantly higher in ADR-resistant TNBC cells than in ADR-sensitive cells, IKKα knockdown results in apoptotic cell death of chemoresistant cells upon drug treatment. Moreover, IKKα knockdown promotes chemotherapeutic drug-induced tumor cell death in an transplanted tumor mouse model. Functionally, we demonstrated that IKKα knockdown significantly upregulated the expression of cleaved caspase 3 and Bax and inhibited the expression of Bcl-2 upon ADR treatment. Our findings highlighted that IKKα exerts an important and previously unknown role in promoting chemoresistance in TNBC, combining IKKα inhibition with chemotherapy may be an effective strategy to improve treatment outcome in chemoresistant TNBC patients.

RNAi-Based Therapeutics and Novel RNA Bioengineering Technologies

RNA interference (RNAi) provides researchers with a versatile means to modulate target gene expression. The major forms of RNAi molecules, genome-derived microRNAs (miRNAs) and exogenous small interfering RNAs (siRNAs), converge into RNA-induced silencing complexes to achieve posttranscriptional gene regulation. RNAi has proven to be an adaptable and powerful therapeutic strategy where advancements in chemistry and pharmaceutics continue to bring RNAi-based drugs into the clinic. With four siRNA medications already approved by the US Food and Drug Administration (FDA), several RNAi-based therapeutics continue to advance to clinical trials with functions that closely resemble their endogenous counterparts. Although intended to enhance stability and improve efficacy, chemical modifications may increase risk of off-target effects by altering RNA structure, folding, and biologic activity away from their natural equivalents. Novel technologies in development today seek to use intact cells to yield true biologic RNAi agents that better represent the structures, stabilities, activities, and safety profiles of natural RNA molecules. In this review, we provide an examination of the mechanisms of action of endogenous miRNAs and exogenous siRNAs, the physiologic and pharmacokinetic barriers to therapeutic RNA delivery, and a summary of the chemical modifications and delivery platforms in use. We overview the pharmacology of the four FDA-approved siRNA medications (patisiran, givosiran, lumasiran, and inclisiran) as well as five siRNAs and several miRNA-based therapeutics currently in clinical trials. Furthermore, we discuss the direct expression and stable carrier-based, in vivo production of novel biologic RNAi agents for research and development. SIGNIFICANCE STATEMENT: In our review, we summarize the major concepts of RNA interference (RNAi), molecular mechanisms, and current state and challenges of RNAi drug development. We focus our discussion on the pharmacology of US Food and Drug Administration-approved RNAi medications and those siRNAs and miRNA-based therapeutics that entered the clinical investigations. Novel approaches to producing new true biological RNAi molecules for research and development are highlighted.

Modulatory role of miRNAs in thyroid and breast cancer progression and insights into their therapeutic manipulation

Over the past few decades, thyroid cancer has become one of the most common types of endocrine cancer, contributing to an increase in prevalence. In the year 2020, there were 586,202 newly diagnosed cases of thyroid cancer around the world. This constituted approximately 3.0% of all patients diagnosed with cancer. The World Health Organization reported that there will be 2.3 million women receiving treatment for breast cancer in 2020, with 685,000. Despite the fact that carcinoma is one of the world's leading causes of death, there is still a paucity of information about its biology. MicroRNAs (miRNAs; miRs) are non-coding RNAs that can reduce gene expression by cleaving the 3' untranslated regions of mRNA. These factors make them a potential protein translation inhibitor. Diverse biological mechanisms implicated in the genesis of cancer are modulated by miRNA. The investigation of global miRNA expression in cancer showed regulatory activity through up regulation and down-regulation in several cancers, including thyroid cancer and breast cancer. In thyroid cancer, miRNA influences several cancers related signaling pathways through modulating MAPK, PI3K, and the RAS pathway. In breast cancer, the regulatory activity of miRNA was played through the cyclin protein family, protein kinases and their inhibitors, and other growth promoters or suppressors, which modulated cell proliferation and cell cycle progression. This article's goal is to discuss key miRNA expressions that are involved in the development of thyroid and breast cancer as well as their therapeutic manipulation for these two specific cancer types.

Polymeric Micelles for Breast Cancer Therapy: Recent Updates, Clinical Translation and Regulatory Considerations

With the growing burden of cancer, parallel advancements in anticancer nanotechnological solutions have been witnessed. Among the different types of cancers, breast cancer accounts for approximately 25% and leads to 15% of deaths. Nanomedicine and its allied fields of material science have revolutionized the science of medicine in the 21st century. Novel treatments have paved the way for improved drug delivery systems that have better efficacy and reduced adverse effects. A variety of nanoformulations using lipids, polymers, inorganic, and peptide-based nanomedicines with various functionalities are being synthesized. Thus, elaborate knowledge of these intelligent nanomedicines for highly promising drug delivery systems is of prime importance. Polymeric micelles (PMs) are generally easy to prepare with good solubilization properties; hence, they appear to be an attractive alternative over the other nanosystems. Although an overall perspective of PM systems has been presented in recent reviews, a brief discussion has been provided on PMs for breast cancer. This review provides a discussion of the state-of-the-art PMs together with the most recent advances in this field. Furthermore, special emphasis is placed on regulatory guidelines, clinical translation potential, and future aspects of the use of PMs in breast cancer treatment. The recent developments in micelle formulations look promising, with regulatory guidelines that are now more clearly defined; hence, we anticipate early clinical translation in the near future.

Current understandings and clinical translation of nanomedicines for breast cancer therapy

Breast cancer is one of the most frequently diagnosed cancers that is threatening women's life. Current clinical treatment regimens for breast cancer often involve neoadjuvant and adjuvant systemic therapies, which somewhat are associated with unfavorable features. Also, the heterogeneous nature of breast cancers requires precision medicine that cannot be fulfilled by a single type of systemically administered drug. Taking advantage of the nanocarriers, nanomedicines emerge as promising therapeutic agents for breast cancer that could resolve the defects of drugs and achieve precise drug delivery to almost all sites of primary and metastatic breast tumors (e.g. tumor vasculature, tumor stroma components, breast cancer cells, and some immune cells). Seven nanomedicines as represented by Doxil® have been approved for breast cancer clinical treatment so far. More nanomedicines including both non-targeting and active targeting nanomedicines are being evaluated in the clinical trials. However, we have to realize that the translation of nanomedicines, particularly the active targeting nanomedicines is not as successful as people have expected. This review provides a comprehensive landscape of the nanomedicines for breast cancer treatment, from laboratory investigations to clinical applications. We also highlight the key advances in the understanding of the biological fate and the targeting strategies of breast cancer nanomedicine and the implications to clinical translation.

Farnesylthiosalicylic acid-derivatized PEI-based nanocomplex for improved tumor vaccination

Cancer vaccines that make use of tumor antigens represent a promising therapeutic strategy by stimulating immune responses against tumors to generate long-term anti-tumor immunity. However, vaccines have shown limited clinical efficacy due to inefficient delivery. In this study, we focus on vaccine delivery assisted by nanocomplexes for cancer immunotherapy. Nanocomplex-mediated vaccination can efficiently deliver nucleic acids encoding neoantigens to lymphoid tissues and antigen-presenting cells. Polyethylenimine (PEI) was conjugated with farnesylthiosalicylic acid (FTS) to form micelles. Subsequent interaction with nucleic acids led to formation of polymer/nucleic acid nanocomplexes of well-controlled structure. Tumor transfection via FTS-PEI was much more effective than that by PEI, other PEI derivatives, or naked DNA. Significant numbers of transfected cells were also observed in draining lymph nodes (LNs). In vivo delivery of ovalbumin (OVA; a model antigen) expression plasmid (pOVA) by FTS-PEI led to a significant growth inhibition of the OVA-expressing B16 tumor through presentation of OVA epitopes as well as other epitopes via epitope spreading. Moreover, in vivo delivery of an endogenous melanoma neoantigen tyrosinase-related protein 2 (Trp2) also led to substantial tumor growth inhibition. FTS-PEI represents a promising transfection agent for effective gene delivery to tumors and LNs to mediate effective neoantigen vaccination.

Co-delivery of sorafenib and crizotinib encapsulated with polymeric nanoparticles for the treatment of in vivo lung cancer animal model

To treat various cancers, including lung cancer, chemotherapy requires the systematic administering of chemotherapy. The chemotherapeutic effectiveness of anticancer drugs has been enhanced by polymer nanoparticles (NPs), according to new findings. As an outcome, we have developed biodegradable triblock poly(ethylene glycol)-poly(ε-caprolactone)-poly(ethylene glycol) (PEG-PCL-PEG, PECE) polymeric NPs for the co-delivery of sorafenib (SORA) and crizotinib (CRIZ) and investigated their effect on lung cancer by in vitro and in vivo. There is little polydispersity in the SORA-CRIZ@NPs, an average size of 30.45 ± 2.89 nm range. A steady release of SORA and CRIZ was observed, with no burst impact. The apoptosis rate of SORA-CRIZ@NPs was greater than that of free drugs in 4T1 and A549 cells. Further, in vitro cytotoxicity of the polymeric NPs loaded with potential anticancer drugs was more quickly absorbed by cancer cells. On the other hand, compared to free drugs (SORA + CRIZ), SORA + CRIZ@NPs showed a substantial reduction of tumor development, longer survival rate, and a lowered side effect when delivered intravenously to nude mice xenograft model with 4T1 cancer cells. TUNEL positivity was also increased in tumor cells treated with SORA-CRIZ@NPs, demonstrating the therapeutic effectiveness. SORA-CRIZ@NPs might be used to treat lung cancer soon, based on the results from our new findings.

Advances of nanomedicines in breast cancer metastasis treatment targeting different metastatic stages

Breast cancer is the most common tumor in women, and the metastasis further increases the malignancy with extremely high mortality. However, there is almost no effective method in the clinic to completely inhibit breast cancer metastasis due to the dynamic multistep process with complex pathways and scattered occurring site. Nowadays, nanomedicines have been evidenced with great potential in treating cancer metastasis. In this review, we summarize the latest research advances of nanomedicines in anti-metastasis treatment. Strategies are categorized according to the metastasis dynamics, including primary tumor, circulating tumor cells, pre-metastatic niches and secondary tumor. In each different stage of metastasis process, nanomedicines are designed specifically with different functions. At the end of the review, we give our perspectives on current limitations and future directions in anti-metastasis therapy. We expect the review provides comprehensive understandings of anti-metastasis therapy for breast cancer, and boosts the clinical translation in the future to improve women's health.

miRNA-Based Therapeutics in Breast Cancer: A Systematic Review

Background

Breast cancer (BC) is the most common cancer in females and despite advances in treatment, it represents the leading cause of cancer mortality in women worldwide. Conventional therapeutic modalities have significantly improved the management of BC patients, but subtype heterogeneity, drug resistance, and tumor relapse remain the major factors to hamper the effectiveness of therapy for BC. In this scenario, miRNA(miR)-based therapeutics offer a very attractive area of study. However, the use of miR-based therapeutics for BC treatment still represents an underdeveloped topic. Therefore, this systematic review aims at summarizing current knowledge on promising miR-based therapeutics for BC exploring original articles focusing on in vivo experiments.

Methods

The current systematic review was performed according to PRISMA guidelines. PubMed and EMBASE databases were comprehensively explored to perform the article search.

Results

Twenty-one eligible studies were included and analyzed: twelve focused on antitumor miR-based therapeutics and nine on metastatic miR-based therapeutics. We found 18 different miRs tested as potential therapeutic molecules in animal model experiments. About 90% of the selected studies evaluate the efficiency and the safety of miRs as therapeutic agents in triple-negative (TN)-BC mouse models. Among all founded miR-based therapeutics, miR-21 emerged to be the most investigated and proposed as a potential antitumoral molecule for TNBC treatment. Besides, miR-34a and miR-205a appeared to be successful antitumoral and antimetastatic molecules.

Conclusions

Our analysis provides a snapshot of the current scenario regarding the miRs as therapeutic molecules in BC. Nevertheless, despite many efforts, none of the selected studies goes beyond preclinical studies, and their translatability in the clinical practice seems quite premature.

The role of microRNAs on doxorubicin drug resistance in breast cancer

OBJECTIVES

Resistance to chemotherapeutic drugs is a serious challenge for effective therapy of cancers. Doxorubicin is a drug which is typically used for breast cancer treatment. Several mechanisms are involved in resistance to doxorubicin including overexpression of ATP-binding cassette (ABC) transporters, altering apoptosis, autophagy and cell cycle arrest. In this review, we focus on the potential effects of microRNAs on doxorubicin resistance in breast cancer.

METHODS

Literature review focusing on the 'microRNAs and doxorubicin drug resistance in breast cancer' was conducted comprehensively. The search was performed in PubMed, Scopus, Google and Google Scholar databases and reference lists of relevant articles were also included.

KEY FINDINGS

MicroRNAs play essential role in resistance of breast cancer to doxorubicin by affecting several key cellular pathways, including overexpression of ABC transporters, altering apoptosis, autophagy and cell signaling pathways, cell cycle arrest, epithelial to mesenchymal transition (EMT) and cancer stem cells (CSCs).

CONCLUSIONS

Cancer treatment methods are moving from conventional therapies to targeted therapies such as using microRNAs. MiRNAs can act as regulatory molecules to overcome breast cancer doxorubicin resistance by controlling the expression levels of genes involved in different cellular pathways. Thus, exact elucidation of their role in different cellular processes can help overcome the breast cancer development and drug resistance.

Therapeutic Targeting of MicroRNAs in the Tumor Microenvironment

The tumor-microenvironment (TME) is an amalgamation of various factors derived from malignant cells and infiltrating host cells, including cells of the immune system. One of the important factors of the TME is microRNAs (miRs) that regulate target gene expression at a post transcriptional level. MiRs have been found to be dysregulated in tumor as well as in stromal cells and they emerged as important regulators of tumorigenesis. In fact, miRs regulate almost all hallmarks of cancer, thus making them attractive tools and targets for novel anti-tumoral treatment strategies. Tumor to stroma cell cross-propagation of miRs to regulate protumoral functions has been a salient feature of the TME. MiRs can either act as tumor suppressors or oncogenes (oncomiRs) and both miR mimics as well as miR inhibitors (antimiRs) have been used in preclinical trials to alter cancer and stromal cell phenotypes. Owing to their cascading ability to regulate upstream target genes and their chemical nature, which allows specific pharmacological targeting, miRs are attractive targets for anti-tumor therapy. In this review, we cover a recent update on our understanding of dysregulated miRs in the TME and provide an overview of how these miRs are involved in current cancer-therapeutic approaches from bench to bedside.

A novel immunochemotherapy based on targeting of cyclooxygenase and induction of immunogenic cell death

Cyclooxygenase (COX) plays a crucial role in the "inflammogenesis of cancer", which leads to tumor progression, metastasis, and immunotherapy resistance. Therefore, reducing "inflammogenesis" by COX inhibition may be a key perspective for cancer therapy. However, the role of tumor-derived COX in the actions of COX inhibitors remains incompletely understood. In this study, applying "old drug new tricks" to repurpose 5-aminosalicylic acid (5-ASA), a COX inhibitor, we examined the effect of 5-ASA, alone or in combination with doxorubicin (DOX), in several cancer cell lines with different levels of COX expression. To facilitate the evaluation of the combination effect on tumors in vivo, a new micellar carrier based on PEG-b-PNHS polymer-conjugated 5-ASA (PASA) was developed to enhance codelivery of 5-ASA and DOX. Folate was also introduced to the polymer (folate-PEG-NH₂-conjugated PASA (FASA)) to further improve delivery to tumors via targeting both tumor cells and tumor macrophages. An unprecedented high DOX loading capacity of 42.28% was achieved through various mechanisms of carrier/drug interactions. FASA was highly effective in targeting to and in inhibiting the growth of both 4T1.2 and CT26 tumors in BALB/c mice. However, FASA was more effective in CT26 tumor that has a high level of COX expression. Codelivery of DOX via PASA and FASA led to a further improvement in antitumor activity. Mechanistic studies suggest that inhibition of COX in vivo led to a more active tumor immune microenvironment. Interestingly, treatment with FASA led to upregulation of PD-1 on T cells, likely due to repressing the inhibitory effect of prostaglandin E2 (PGE₂) on PD-1 expression on T cells. Combination of FASA/DOX with anti-PD-1 antibody led to a drastic improvement in the overall antitumor activity including regression of some established tumors at a suboptimal dose of FASA/DOX. Our data suggest that FASA/DOX may represent a new and effective immunochemotherapy for various types of cancers, particularly those cancers with high levels of COX expression.

Metformin-conjugated micellar system with intratumoral pH responsive de-shielding for co-delivery of doxorubicin and nucleic acid

A novel PMet-P(cdmPEG_2K) polymeric micellar carrier was developed for tumor-targeted co-delivery of DOX and nucleic acids (NA), based on polymetformin and a structure designed to lose the PEG shell in response to the acidic extracellular tumor environment. NA/DOX co-loaded micelleplexes exhibited enhanced inhibition of cell proliferation compared to DOX-loaded micelles, and displayed a higher level of cytotoxicity at an acidic pH (6.8) which mimicks the tumor microenvironment. The PMet-P(cdmPEG_2K) micelles achieved significantly improved transfection with either a reporter plasmid or Cy3-siRNA, and enhanced DOX intracellular uptake in 4T1.2 cells at pH 6.8. Importantly, PMet-P(cdmPEG_2K) micelles showed excellent pEGFP (EGFP expression plasmid) transfection in an aggressive murine breast cancer (4T1.2) model. By using a plasmid encoding IL-12 (pIL-12), we investigated the combined effect of chemotherapy and gene therapy. PMet-P(cdmPEG_2K) micelles co-loaded with DOX and pIL-12 were more effective at inhibiting tumor growth compared to micelles loaded with DOX or pIL-12 alone. In addition, this micellar system was effective in co-delivery of siRNA and DOX into tumor cells. Our results suggest that PMet-P(cdmPEG_2K) has the potential for chemo and nucleic acid combined cancer therapy.

3D Hybrid Nanofiber Aerogels Combining with Nanoparticles Made of a Biocleavable and Targeting Polycation and MiR-26a for Bone Repair

The healing of large bone defects represents a clinical challenge, often requiring some form of grafting. Three-dimensional (3D) nanofiber aerogels could be a promising bone graft due to their biomimetic morphology and controlled porous structures and composition. miR-26a has been reported to induce the differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) and facilitate bone formation. Introducing miR-26a with a suitable polymeric vector targeting BMSCs could improve and enhance the functions of 3D nanofiber aerogels for bone regeneration. Herein, we first developed the comb-shaped polycation (HA-SS-PGEA) carrying a targeting component, biocleavable groups and short ethanolamine (EA)-decorated poly(glycidyl methacrylate) (PGMA) (abbreviated as PGEA) arms as miR-26a delivery vector. We then assessed the cytotoxicity and transfection efficiency of this polycation and cellular response to miR-26a-incorporated nanoparticles (NPs) in vitro. HA-SS-PGEA exhibited a stronger ability to transport miR-26a and exert its functions than the gold standard polyethyleneimine (PEI) and low-molecular-weight linear PGEA. We finally examined the efficacy of HA-SS-PGEA/miR-26a NPs loaded 3D hybrid nanofiber aerogels showing a positive effect on the cranial bone defect healing. Together, the combination of 3D nanofiber aerogels and functional NPs consisting of a biodegradable and targeting polycation and therapeutic miRNA could be a promising approach for bone regeneration.

RNA Drugs and RNA Targets for Small Molecules: Principles, Progress, and Challenges

RNA-based therapies, including RNA molecules as drugs and RNA-targeted small molecules, offer unique opportunities to expand the range of therapeutic targets. Various forms of RNAs may be used to selectively act on proteins, transcripts, and genes that cannot be targeted by conventional small molecules or proteins. Although development of RNA drugs faces unparalleled challenges, many strategies have been developed to improve RNA metabolic stability and intracellular delivery. A number of RNA drugs have been approved for medical use, including aptamers (e.g., pegaptanib) that mechanistically act on protein target and small interfering RNAs (e.g., patisiran and givosiran) and antisense oligonucleotides (e.g., inotersen and golodirsen) that directly interfere with RNA targets. Furthermore, guide RNAs are essential components of novel gene editing modalities, and mRNA therapeutics are under development for protein replacement therapy or vaccination, including those against unprecedented severe acute respiratory syndrome coronavirus pandemic. Moreover, functional RNAs or RNA motifs are highly structured to form binding pockets or clefts that are accessible by small molecules. Many natural, semisynthetic, or synthetic antibiotics (e.g., aminoglycosides, tetracyclines, macrolides, oxazolidinones, and phenicols) can directly bind to ribosomal RNAs to achieve the inhibition of bacterial infections. Therefore, there is growing interest in developing RNA-targeted small-molecule drugs amenable to oral administration, and some (e.g., risdiplam and branaplam) have entered clinical trials. Here, we review the pharmacology of novel RNA drugs and RNA-targeted small-molecule medications, with a focus on recent progresses and strategies. Challenges in the development of novel druggable RNA entities and identification of viable RNA targets and selective small-molecule binders are discussed. SIGNIFICANCE STATEMENT: With the understanding of RNA functions and critical roles in diseases, as well as the development of RNA-related technologies, there is growing interest in developing novel RNA-based therapeutics. This comprehensive review presents pharmacology of both RNA drugs and RNA-targeted small-molecule medications, focusing on novel mechanisms of action, the most recent progress, and existing challenges.

Potential miRNAs for miRNA-Based Therapeutics in Breast Cancer

MicroRNAs (miRNAs) are small non-coding RNAs that can post-transcriptionally regulate the genes involved in critical cellular processes. The aberrant expressions of oncogenic or tumor suppressor miRNAs have been associated with cancer progression and malignancies. This resulted in the dysregulation of signaling pathways involved in cell proliferation, apoptosis and survival, metastasis, cancer recurrence and chemoresistance. In this review, we will first (i) provide an overview of the miRNA biogenesis pathways, and in vitro and in vivo models for research, (ii) summarize the most recent findings on the roles of microRNAs (miRNAs) that could potentially be used for miRNA-based therapy in the treatment of breast cancer and (iii) discuss the various therapeutic applications.

Polymer-Drug Conjugate, a Potential Therapeutic to Combat Breast and Lung Cancer

Cancer is a chronic disease that is responsible for the high death rate, globally. The administration of anticancer drugs is one crucial approach that is employed for the treatment of cancer, although its therapeutic status is not presently satisfactory. The anticancer drugs are limited pharmacologically, resulting from the serious side effects, which could be life-threatening. Polymer drug conjugates, nano-based drug delivery systems can be utilized to protect normal body tissues from the adverse side effects of anticancer drugs and also to overcome drug resistance. They transport therapeutic agents to the target cell/tissue. This review article is based on the therapeutic outcomes of polymer-drug conjugates against breast and lung cancer.

Novel approaches for efficient in vivo fermentation production of noncoding RNAs

Genome-derived noncoding RNAs (ncRNAs), including microRNAs (miRNAs), small interfering RNAs (siRNAs), and long noncoding RNAs (lncRNAs), play an essential role in the control of target gene expression underlying various cellular processes, and dysregulation of ncRNAs is involved in the pathogenesis and progression of various diseases in virtually all species including humans. Understanding ncRNA biology has opened new avenues to develop novel RNA-based therapeutics. Presently, ncRNA research and drug development is dominated by the use of ncRNA mimics that are synthesized chemically in vitro and supplemented with extensive and various types of artificial modifications and thus may not necessarily recapitulate the properties of natural RNAs generated and folded in living cells in vivo. Therefore, there are growing interests in developing novel technologies for in vivo production of RNA molecules. The two most recent major breakthroughs in achieving an efficient, large-scale, and cost-effective fermentation production of recombinant or bioengineered RNAs (e.g., tens of milligrams from 1 L of bacterial culture) are (1) using stable RNA carriers and (2) direct overexpression in RNase III-deficient bacteria, while other approaches offer a low yield (e.g., nano- to microgram scales per liter). In this article, we highlight these novel microbial fermentation-based technologies that have shifted the paradigm to the production of true biological ncRNA molecules for research and development.

The Optimal Outcome of Suppressing Ewing Sarcoma Growth in vivo With Biocompatible Bioengineered miR-34a-5p Prodrug

Being the second most common type of primary bone malignancy in children and adolescents, Ewing Sarcoma (ES) encounters the dilemma of low survival rate with a lack of effective treatments. As an emerging approach to combat cancer, RNA therapeutics may expand the range of druggable targets. Since the genome-derived oncolytic microRNA-34a (miR-34a) is down-regulated in ES, restoration of miR-34a-5p expression or function represents a new therapeutic strategy which is, however, limited to the use of chemically-engineered miRNA mimics. Very recently we have developed a novel bioengineering technology using a stable non-coding RNA carrier (nCAR) to achieve high-yield production of biocompatible miRNA prodrugs, which is a great addition to current tools for the assessment of RNA therapeutics. Herein, for the first time, we investigated the biochemical pharmacology of bioengineered miR-34a-5p prodrug (nCAR/miR-34a-5p) in the control of ES using human ES cells and xenograft mouse models. The bioengineered nCAR/miR-34a-5p was precisely processed to mature miR-34a-5p in ES cells and subsequently suppressed cell proliferation, attributable to the enhancement of apoptosis and induction of G2 cell cycle arrest through downregulation of SIRT-1, BCL-2 and CDK6 protein levels. Furthermore, systemic administration of nCAR/miR-34a-5p dramatically suppressed the ES xenograft tumor growth in vivo while showing biocompatibility. In addition, the antitumor effect of bioengineered nCAR/miR-34a-5p was associated with a lower degree of tumoral cell proliferation and greater extent of apoptosis. These findings demonstrate the efficacy of bioengineered miR-34a-5p prodrug for the treatment of ES and support the development of miRNA therapeutics using biocompatible bioengineered miRNA prodrugs.

MicroRNAs and Metastasis

Metastasis, the development of secondary malignant growths at a distance from the primary site of a cancer, is associated with almost 90% of all cancer deaths, and half of all cancer patients present with some form of metastasis at the time of diagnosis. Consequently, there is a clear clinical need for a better understanding of metastasis. The role of miRNAs in the metastatic process is beginning to be explored. However, much is still to be understood. In this review, we present the accumulating evidence for the importance of miRNAs in metastasis as key regulators of this hallmark of cancer.

Advances and challenges in studying noncoding RNA regulation of drug metabolism and development of RNA therapeutics

Accumulating evidence has demonstrated that genome-derived noncoding RNAs (ncRNAs) play important roles in modulating inter-individual variations observed in drug metabolism and disposition by controlling the expression of genes coding drug metabolizing enzymes and transporters (DMETs) and relevant nuclear receptors (NRs). With the understanding of novel ncRNA regulatory mechanisms and significance in the control of disease initiation and progression, RNA-based therapies are under active investigation that may expand the druggable targets from conventional proteins to RNAs and the genome for the treatment of human diseases. Herein we provide an overview of research strategies, approaches and their limitations in biochemical and pharmacological studies pertaining to ncRNA functions in the regulation of drug and nutrient metabolism and disposition, and discussion on the promise and challenges in developing RNA therapeutics.