Nucleopeptide Assemblies Selectively Sequester ATP in Cancer Cells to Increase the Efficacy of Doxorubicin

Dancing with Nucleobases: Unveiling the Self-Assembly Properties of DNA and RNA Base-Containing Molecules for Gel Formation

Nucleobase-containing molecules are compounds essential in biology due to the fundamental role of nucleic acids and, in particular, G-quadruplex DNA and RNA in life. Moreover, some molecules different from nucleic acids isolated from different vegetal sources or microorganisms show nucleobase moieties in their structure. Nucleoamino acids and peptidyl nucleosides belong to this molecular class. Closely related to the above, nucleopeptides, also known as nucleobase-bearing peptides, are chimeric derivatives of synthetic origin and more rarely isolated from plants. Herein, the self-assembly properties of a vast number of structures, belonging to the nucleic acid and nucleoamino acid/nucleopeptide family, are explored in light of the recent scientific literature. Moreover, several technologically relevant properties, such as the hydrogelation ability of some of the nucleobase-containing derivatives, are reviewed in order to make way for future experimental investigations of newly devised nucleobase-driven hydrogels. Nucleobase-containing molecules, such as mononucleosides, DNA, RNA, quadruplex (G4)-forming oligonucleotides, and nucleopeptides are paramount in gel and hydrogel formation owing to their distinctive molecular attributes and ability to self-assemble in biomolecular nanosystems with the most diverse applications in different fields of biomedicine and nanotechnology. In fact, these molecules and their gels present numerous advantages, underscoring their significance and applicability in both material science and biomedicine. Their versatility, capability for molecular recognition, responsiveness to stimuli, biocompatibility, and biodegradability collectively contribute to their prominence in modern nanotechnology and biomedicine. In this review, we emphasize the critical role of nucleobase-containing molecules of different nature in pioneering novel materials with multifaceted applications, highlighting their potential in therapy, diagnostics, and new nanomaterials fabrication as required for addressing numerous current biomedical and nanotechnological challenges.

Diversity of Bioinspired Hydrogels: From Structure to Applications

Hydrogels are three-dimensional networks with a variety of structures and functions that have a remarkable ability to absorb huge amounts of water or biological fluids. They can incorporate active compounds and release them in a controlled manner. Hydrogels can also be designed to be sensitive to external stimuli: temperature, pH, ionic strength, electrical or magnetic stimuli, specific molecules, etc. Alternative methods for the development of various hydrogels have been outlined in the literature over time. Some hydrogels are toxic and therefore are avoided when obtaining biomaterials, pharmaceuticals, or therapeutic products. Nature is a permanent source of inspiration for new structures and new functionalities of more and more competitive materials. Natural compounds present a series of physico-chemical and biological characteristics suitable for biomaterials, such as biocompatibility, antimicrobial properties, biodegradability, and nontoxicity. Thus, they can generate microenvironments comparable to the intracellular or extracellular matrices in the human body. This paper discusses the main advantages of the presence of biomolecules (polysaccharides, proteins, and polypeptides) in hydrogels. Structural aspects induced by natural compounds and their specific properties are emphasized. The most suitable applications will be highlighted, including drug delivery, self-healing materials for regenerative medicine, cell culture, wound dressings, 3D bioprinting, foods, etc.

Redox homeostasis modulation using theranostic AIE nanoparticles results in positive-feedback drug accumulation and enhanced drug penetration to combat drug-resistant cancer

Drug-resistant cancers usually have multiple barriers to compromise the effect of therapies, of which multidrug-resistance (MDR) phenotype as the intracellular barrier and dense tumor matrix as the extracellular barrier, significantly contribute to the poor anticancer performance of current drug delivery systems (DDS). Here in this study, we fabricated a novel aggregation-induced emission (AIE)-active polymer capable of self-assembling into ultrasmall nanoparticles (∼20 ​nm) with D-alpha Tocopheryl Polyethylene Glycol Succinate (TPGS), for dual-encapsulating of doxorubicin (Dox) and sulforaphane (SFN) (AT/Dox/SFN). It revealed that redox homeostasis modulation of MDR cells (MCF-7/Adr) using AT/Dox/SFN can trigger mitochondria damage and ATP deficiency, which reverse the MDR phenotype of MCF-7/Adr cells to afford enhanced cellular uptake of both drug and DDS in a positive-feedback manner. The enhanced cellular drug accumulation further initiates the “neighboring effect” for improved drug penetration. Using this strategy, the growth of in vivo MCF-7/Adr tumors can be effectively inhibited at a low dosage (1/5) of doxorubicin (Dox) as compared to free Dox. In summary, we offer a new approach to overcome both the intracellular and extracellular barriers of drug-resistant cancers and elucidate the potential action mechanisms, which are beneficial for better cancer management.

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Redox homeostasis modulation in MDR cancer cell results in positive-feedback drug accumulation and enhanced drug penetration.

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Mitochondria damage and neighboring effect is responsible for MDR reversal and enhanced drug penetration, respectively.

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AT/Dox/SFN effectively inhibits ​in vivo ​MCF-7/Adr tumors at a low dosage (1/5) of doxorubicin (Dox) as compared to free Dox.

Intramitochondrial co-assembly between ATP and nucleopeptides induces cancer cell apoptosis

Mitochondria are essential intracellular organelles involved in many cellular processes, especially adenosine triphosphate (ATP) production. Since cancer cells require high ATP levels for proliferation, ATP elimination can be a unique target for cancer growth inhibition. We describe a newly developed mitochondria-targeting nucleopeptide (MNP) that sequesters ATP by self-assembling with ATP inside mitochondria. MNP interacts strongly with ATP through electrostatic and hydrogen bonding interactions. MNP exhibits higher binding affinity for ATP (-637.5 kJ mol-1) than for adenosine diphosphate (ADP) (-578.2 kJ mol-1). To improve anticancer efficacy, the small-sized MNP/ADP complex formed large assemblies with ATP inside cancer cell mitochondria. ATP sequestration and formation of large assemblies of the MNP/ADP-ATP complex inside mitochondria caused physical stress by large structures and metabolic disorders in cancer cells, leading to apoptosis. This work illustrates a facile approach to developing cancer therapeutics that relies on molecular assemblies.

From Prebiotic Chemistry to Supramolecular Biomedical Materials: Exploring the Properties of Self-Assembling Nucleobase-Containing Peptides

Peptides and their synthetic analogs are a class of molecules with enormous relevance as therapeutics for their ability to interact with biomacromolecules like nucleic acids and proteins, potentially interfering with biological pathways often involved in the onset and progression of pathologies of high social impact. Nucleobase-bearing peptides (nucleopeptides) and pseudopeptides (PNAs) offer further interesting possibilities related to their nucleobase-decorated nature for diagnostic and therapeutic applications, thanks to their reported ability to target complementary DNA and RNA strands. In addition, these chimeric compounds are endowed with intriguing self-assembling properties, which are at the heart of their investigation as self-replicating materials in prebiotic chemistry, as well as their application as constituents of innovative drug delivery systems and, more generally, as novel nanomaterials to be employed in biomedicine. Herein we describe the properties of nucleopeptides, PNAs and related supramolecular systems, and summarize some of the most relevant applications of these systems.

Assemblies of Peptides in a Complex Environment and their Applications

Using peptide assemblies with emergent properties to achieve elaborate functions has attracted increasing attention in recent years. Besides tailoring the self-assembly of peptides in vitro, peptide research is advancing into a new and exciting frontier: the rational design of peptide assemblies (or their derivatives) for biological functions in a complex environment. This Minireview highlights recent developments in peptide assemblies and their applications in biological systems. After introducing the unique merits of peptide assemblies, we discuss the recent progress in designing peptides (or peptide derivatives) for self-assembly with conformational control. Then, we describe biological functions of peptide assemblies, with an emphasis on approach-instructed assembly for spatiotemporal control of peptide assemblies, in the cellular context. Finally, we discuss the future promises and challenges of this exciting area of chemistry.

Investigation of the Stereochemical-Dependent DNA and RNA Binding of Arginine-Based Nucleopeptides

Nucleopeptides represent an intriguing class of nucleic acid analogues, in which nucleobases are placed in a peptide structure. The incorporation of D- and/or L-amino acids in nucleopeptide molecules allows the investigation of the role of backbone stereochemistry in determining the formation of DNA and RNA hybrids. Circular Dichroism (CD) spectroscopic studies indicated the nucleopeptide as having fully l-backbone configuration-formed stable hybrid complexes with RNA molecules. Molecular Dynamics (MD) simulations suggested a potential structure of the complex resulting from the interaction between the l-nucleopeptide and RNA strand. From this study, both the backbone (ionics and H-bonds) and nucleobases (pairing and π-stacking) of the chiral nucleopeptide appeared to be involved in the hybrid complex formation, highlighting the key role of the backbone stereochemistry in the formation of the nucleopeptide/RNA complexes.

Supramolecular Nanofibers with Superior Bioactivity to Insulin-Like Growth Factor-I

Bioactive peptides derived from proteins generally need to be folded into secondary structures to activate downstream signaling pathways. However, synthetic peptides typically form random-coils, thus losing their bioactivities. Here, we show that by introducing a self-assembling peptide motif and using different preparation pathways, a peptide from insulin-like growth factor-I (IGF-1) can be folded into an α-helix and β-sheet. The β-sheet one exhibits a low dissociation constant to the IGF-1 receptor (IGF-1R, 11.5 nM), which is only about 3 times higher than that of IGF-1 (4.3 nM). However, the α-helical one and the peptide without self-assembling motif show weak affinities to IGF-1R ( K_D = 179.1 and 321.6 nM, respectively). At 10 nM, the β-sheet one efficiently activates the IGF-1 downstream pathway, significantly enhancing HUVEC proliferation and preventing cell apoptosis. The β-sheet peptide shows superior performance to IGF-1 in vivo, and it improves ischemic hind-limb salvage by significantly reducing muscle degradation and enhancing limb vascularization. Our study provides a useful strategy to constrain peptides into different conformations, which may lead to the development of supramolecular nanomaterials mimicking biofunctional proteins.