Conformation-dependent binding and tumor-targeted delivery of siRNA by a designed TRBP2: Affibody fusion protein

RNA-binding proteins in breast cancer: Biological implications and therapeutic opportunities

RNA-binding proteins (RBPs) refer to a class of proteins that participate in alternative splicing, RNA stability, polyadenylation, localization and translation of RNAs, thus regulating gene expression in post-transcriptional manner. Dysregulation of RNA-RBP interaction contributes to various diseases, including cancer. In breast cancer, disorders in RBP expression and function influence the biological characteristics of tumor cells. Targeting RBPs has fostered the development of innovative therapies for breast cancer. However, the RBP-related mechanisms in breast cancer are not completely clear. In this review, we summarize the regulatory mechanisms of RBPs and their signaling crosstalk in breast cancer. Specifically, we emphasize the potential of certain RBPs as prognostic factors due to their effects on proliferation, invasion, apoptosis, and therapy resistance of breast cancer cells. Most importantly, we present a comprehensive overview of the latest RBP-related therapeutic strategies and novel therapeutic targets that have proven to be useful in the treatment of breast cancer.

Protein-based delivery systems for RNA delivery

RNA-based therapeutics have emerged as promising approaches to modulate gene expression and generate therapeutic proteins or antigens capable of inducing immune responses to treat a variety of diseases, such as infectious diseases, cancers, immunologic disorders, and genetic disorders. However, the efficient delivery of RNA molecules into cells poses significant challenges due to their large molecular weight, negative charge, and susceptibility to degradation by RNase enzymes. To overcome these obstacles, viral and non-viral vectors have been developed, including lipid nanoparticles, viral vectors, proteins, dendritic macromolecules, among others. Among these carriers, protein-based delivery systems have garnered considerable attention due to their potential to address specific issues associated with nanoparticle-based systems, such as liver accumulation and immunogenicity. This review provides an overview of currently marketed RNA drugs, underscores the significance of RNA delivery vector development, delineates the essential characteristics of an ideal RNA delivery vector, and introduces existing protein carriers for RNA delivery. By offering valuable insights, this review aims to serve as a reference for the future development of protein-based delivery vectors for RNA therapeutics.

Surface Functionalization of Gold Nanoparticles for Targeting the Tumor Microenvironment to Improve Antitumor Efficiency

Gold nanoparticles (AuNPs) have undergone significant research for their use in the treatment of cancer. Numerous researchers have established their potent antitumor properties, which have greatly impacted the treatment of cancer. AuNPs have been used in four primary anticancer treatment modalities, namely radiation, photothermal therapy, photodynamic therapy, and chemotherapy. However, the ability of AuNPs to destroy cancer is lacking and can even harm healthy cells without the right direction to transport them to the tumor microenvironment. Consequently, a suitable targeting technique is needed. Based on the distinct features of the human tumor microenvironment, this review discusses four different targeting strategies that target the four key features of the tumor microenvironment, including abnormal vasculature, overexpression of specific receptors, an acidic microenvironment, and a hypoxic microenvironment, to direct surface-functionalized AuNPs to the tumor microenvironment and increase antitumor efficacies. In addition, some current completed or ongoing clinical trials of AuNPs will also be discussed below to further reinforce the concept of using AuNPs in anticancer therapy.

Extracellular vesicles: A new paradigm in understanding, diagnosing and treating neurodegenerative disease

Neurodegenerative disorders (NDs) are becoming one of the leading causes of disability and death across the globe due to lack of timely preventions and treatments. Concurrently, intensive research efforts are being carried out to understand the etiology of these age-dependent disorders. Extracellular vesicles (EVs)-biological nanoparticles released by cells-are gaining tremendous attention in understanding their role in pathogenesis and progression of NDs. EVs have been found to transmit pathogenic proteins of NDs between neurons. Moreover, the ability of EVs to exquisitely surmount natural biological barriers, including blood-brain barrier and in vivo safety has generated interest in exploring them as potential biomarkers and function as natural delivery vehicles of drugs to the central nervous system. However, limited knowledge of EV biogenesis, their heterogeneity and lack of adequate isolation and analysis tools have hampered their therapeutic potential. In this review, we cover the recent advances in understanding the role of EVs in neurodegeneration and address their role as biomarkers and delivery vehicles to the brain.

GAPDH controls extracellular vesicle biogenesis and enhances the therapeutic potential of EV mediated siRNA delivery to the brain

Extracellular vesicles (EVs) are biological nanoparticles with important roles in intercellular communication, and potential as drug delivery vehicles. Here we demonstrate a role for the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in EV assembly and secretion. We observe high levels of GAPDH binding to the outer surface of EVs via a phosphatidylserine binding motif (G58), which promotes extensive EV clustering. Further studies in a Drosophila EV biogenesis model reveal that GAPDH is required for the normal generation of intraluminal vesicles in endosomal compartments, and promotes vesicle clustering. Fusion of the GAPDH-derived G58 peptide to dsRNA-binding motifs enables highly efficient loading of small interfering RNA (siRNA) onto the EV surface. Such vesicles efficiently deliver siRNA to multiple anatomical regions of the brain in a Huntington's disease mouse model after systemic injection, resulting in silencing of the huntingtin gene in different regions of the brain.

Extrahepatic Targeting of Oligonucleotides with Receptor-Binding Non-Immunoglobulin Scaffold Proteins

Although recent clinical successes of antisense, splice-switching, and siRNA oligonucleotides have established the therapeutic utility of this novel class of medicines, the efficient systemic application for non-liver targets remains elusive. Exploitation of active receptor-mediated targeting followed by efficient and productive cellular uptake is required for enabling the therapy of extrahepatic diseases on the expressional level. Evasion of liver accumulation and organ-specific targeting and also efficient cytosolic delivery after endosomal internalization are currently insufficiently solved issues. Lipid and polymer-based nanoparticles can be engineered for efficient cellular uptake and enhancement of endosomal escape, but are characterized by preferential liver accumulation based on biodistribution largely determined by particle size and biophysical properties. Oligonucleotide bioconjugates with receptor-binding ligands have been evolved for highly efficient targeting, but frequently result in a large extent of endosomal entrapment and consequently a lack of sufficient cytosolic concentrations. Non-immunoglobulin protein-based receptor recognition affords high cell-type selectivity and is promising for achieving nonhepatic oligonucleotide targeting. The use of such novel protein scaffolds, including designed ankyrin repeat proteins (DARPins), for oligonucleotide delivery is attractive for achieving effective tissue targeting. Issues for further development and optimization to advance approaches for extrahepatic oligonucleotide delivery by nanoparticles or bioconjugates are discussed.

Affibody molecules for molecular imaging and targeted drug delivery in the management of breast cancer

Breast cancer is one of the leading reasons for the morbidity and mortality of cancer related death globally. The modern therapies are basically the combination of the breast-preserving surgeries or ablation with or without node biopsy or destroying the carcinoma cells adjuvant with chemotherapy, radiotherapy, hormonal or biological therapies depending upon the nature of the receptor of the cancerous cells, nature of the lymph node, as well as the tendency of the recurrence. For decade's carcinoma management suffered by the limitation of imagining, targeting and penetrability problem associated with management and cure of this deadly disease leads to unwanted chemo-toxicity and side effects. Alike other antibody mimetics, affibodies are designed with the combinatorial protein engineering approaches which are small and robust protein scaffolds retaining the favorable folding and stability. Affibody is one of the significantly important tools for imaging and diagnosis of the affinity specific over expressed proteins in the breast cancer management. The review summarizes the various affibody strategies uses in the management of breast cancer.

Affibody Molecules in Biotechnological and Medical Applications

Affibody molecules are small (6.5-kDa) affinity proteins based on a three-helix bundle domain framework. Since their introduction 20 years ago as an alternative to antibodies for biotechnological applications, the first therapeutic affibody molecules have now entered clinical development and more than 400 studies have been published in which affibody molecules have been developed and used in a variety of contexts. In this review, we focus primarily on efforts over the past 5 years to explore the potential of affibody molecules for medical applications in oncology, neurodegenerative, and inflammation disorders, including molecular imaging, receptor signal blocking, and delivery of toxic payloads. In addition, we describe recent examples of biotechnological applications, in which affibody molecules have been exploited as modular affinity fusion partners.

Functional peptides for siRNA delivery

siRNA is considered as a potent therapeutic agent because of its high specificity and efficiency in suppressing genes that are overexpressed during disease development. For nearly two decades, a significant amount of efforts has been dedicated to bringing the siRNA technology into clinical uses. However, only limited success has been achieved to date, largely due to the lack of a cell type-specific, safe, and efficient delivery technology to carry siRNA into the target cells' cytosol where RNA interference takes place. Among the emerging candidate nanocarriers for siRNA delivery, peptides have gained popularity because of their structural and functional diversity. A variety of peptides have been discovered for their ability to translocate siRNA into living cells via different mechanisms such as direct penetration through the cellular membrane, endocytosis-mediated cell entry followed by endosomolysis, and receptor-mediated uptake. This review is focused on the multiple roles played by peptides in siRNA delivery, such as membrane penetration, endosome disruption, targeting, as well as the combination of these functionalities.

Engineered fusion protein-loaded gold nanocarriers for targeted co-delivery of doxorubicin and erbB2-siRNA in human epidermal growth factor receptor-2+ ovarian cancer

Gold nanoparticle based targeted drug delivery system (TDDS) for transporting DX and siRNA in HER2+ ovarian cancer.