Search Results (207)

Background: Antibody–drug conjugates (ADCs) have evolved from early heterogeneous constructs into a mature therapeutic platform with exponential clinical relevance. This review highlights recent advances in ADC design and development, with emphasis on antigen selection, antibody engineering, linker and payload innovation, site-specific conjugation, clinical translation, toxicity, resistance, and emerging data-driven approaches. Methods: The review draws on the literature published from 2019 to the recent clinical and regulatory developments relevant to approved and late-stage ADCs, emphasizing the advances in target biology, antibody formats, linker chemistry, payload classes, conjugation technologies, developability assessment, and computational or artificial intelligence-assisted design strategies. Results: ADC development has evolved with improved target selection, enhanced internalization and tumor selectivity, and the use of engineered, bispecific, biparatopic, and fragment-based antibody formats. Linker and payload innovation has expanded beyond traditional microtubule inhibitors to include topoisomerase I inhibitors, DNA-damaging agents, and emerging dual-payload or non-cytotoxic strategies. Site-specific conjugation and improved control of drug-to-antibody ratio have increased stability, pharmacokinetic performance, and manufacturability. Clinically, ADCs are being used across a broader range of malignancies and treatment settings, although toxicities and resistance mechanisms remain an important limitations. Computational methods and artificial intelligence are increasingly being explored for target discovery, molecular optimization, toxicity prediction, and model-informed clinical development. Conclusions: ADCs are transitioning toward a more integrated, design-driven platform in which antigen biology, antibody format, chemistry, and computational prediction are jointly optimized. Future progress will depend on improved standardization, biomarker-guided development, and interdisciplinary approaches to enhance its therapeutic index and expand its applications beyond oncology. Full article

Lipid-based nanoparticles are widely explored as non-viral vectors for nucleic acid delivery, where the molecular structure of cationic lipids strongly determines their performance. Five-membered heterocyclic linkers were explored as a new structural motif in cationic amphiphilic lipids for the development of promising gene delivery candidates. Novel lipids incorporating pyrrole, furan, and thiophene linkers were synthesized alongside structurally related aliphatic analogues, enabling systematic evaluation of how linker type influences physicochemical behavior and self-assembly properties. Self-assembly behavior in aqueous media was characterized by dynamic light scattering, and pDNA encapsulation efficiency was measured using the Quant-iT Pico-Green method. The resulting liposomes exhibited hydrodynamic diameters ranging from 92 to 1317 nm, while corresponding lipoplexes ranged from 302 to 1159 nm. Amphiphiles containing heterocyclic linkers demonstrated high pDNA encapsulation (>80% at optimal N/P ratios), whereas aliphatic analogues showed significantly reduced performance. These results demonstrate that linker structure strongly influences both self-assembly and nucleic acid binding properties. By evaluating structure–activity relationships, five-membered heterocycles are proposed as promising structural elements for the rational development of lipid-based gene delivery candidates. Full article

Colorectal cancer is the third most commonly diagnosed cancer worldwide and the second leading cause of cancer-related deaths, while its resistance to treatment continues to represent a major therapeutic challenge. In the present study, a series of phenothiazine derivatives, including hybrids containing a 1,2,3-triazole linker and the zidovudine (AZT) fragment, were synthesized and evaluated for their anticancer activity against colorectal cancer cell lines HCT116 and HT-29 as well as non-cancerous BEAS-2B cells. Cytotoxic activity was determined using the Alamar Blue assay, while the mechanisms of action were investigated by flow cytometric analysis of apoptosis, cell cycle progression, and reactive oxygen species (ROS) generation. Additionally, changes in the expression of genes associated with apoptosis, oxidative stress, and DNA damage response were analyzed by RT-qPCR. The obtained results demonstrated that AZT-containing derivatives exhibited stronger anticancer activity than non-conjugated phenothiazine analogs. Compounds A9–A12 induced pronounced apoptosis and significant disturbances in cell cycle progression, particularly in HCT116 cells. Among the analyzed derivatives, compound A9 displayed the most favorable overall biological profile, combining strong proapoptotic and cytotoxic activity with relatively high selectivity toward cancer cells and moderate effects on non-cancerous cells. The results indicate that molecular hybridization of phenothiazine derivatives with the AZT scaffold represents a promising strategy for the development of novel anticancer agents targeting colorectal cancer. Full article

DNA viruses rely extensively on host cellular machinery, including replication factors and transcriptional systems, to persist after infection. These mechanisms make studying and targeting DNA viral proteins challenging, as they also play key roles in mammalian processes. Traditional strategies include CRISPR-mediated gene disruption and small interfering RNA (siRNA) to target host proteins. However, Proteolysis Targeting Chimeras (PROTACs) offer a novel strategy by enabling the selective and rapid degradation of specific viral or host proteins involved in the DNA viral lifecycle. PROTACs are heterobifunctional molecules composed of three key components: a ligand that binds the target protein, a chemical linker, and a ligand that recruits an E3 ubiquitin ligase. By simultaneously binding both the target protein and the E3 ligase, PROTACs form a ternary complex. This proximity enables the E3 ligase to ubiquitinate the target protein, marking it for recognition and subsequent degradation by the intracellular proteasome. This approach represents a promising avenue for targeting previously undruggable proteins and improving therapeutic outcomes in virus-associated malignancies. In this perspective, we describe studies that use PROTACs as tools to modulate host proteins to investigate DNA viral processes with temporal control of host protein expression, as well as the use of PROTACs as antivirals to directly target DNA viral proteins. We also provide a detailed chart summarizing known host-targeting PROTACs and their potential applications across different stages of DNA viral lifecycles, highlighting opportunities for future DNA virus research. Full article

Antibody–drug conjugates (ADCs) have become an important class of targeted anticancer therapeutics by integrating the tumor selectivity of monoclonal antibodies with the potent cytotoxicity of small-molecule payloads through rational linker design. This review summarizes the structural fundamentals of ADCs, including antibodies, linkers, and payloads, and describes their coordinated mechanism of action. We trace the evolutionary trajectory of ADCs across three generations, highlighting key breakthroughs, limitations, and representative agents for each era. Furthermore, we elaborate on cleavage mechanisms of linkers (cleavable and non-cleavable). We also categorize and discuss cytotoxic payloads, covering traditional microtubule-disrupting agents, DNA-damaging agents, and novel mechanism-based payloads, along with their modification strategies and preclinical/clinical performance. Finally, we discuss representative and clinically influential ADC designs, with emphasis on the relationships among antibody, linker, and payload. Full article

The optimization of membrane permeability is a pivotal approach for mitigating late-stage failures in peptide drug development. By leveraging linker chemical diversity, stapled peptides utilize linker engineering to precisely modulate key physicochemical parameters—such as lipophilicity and conformational constraints—to overcome the desolvation energy penalty. This review systematically evaluates linker-based strategies for enhancing the permeability of stapled peptides, categorized into two primary dimensions: (1) high-throughput screening (HTS) compatibility, focusing on the integration of functionalized linkers into mRNA display, phage display, and DNA-encoded libraries (DELs) to identify lead scaffolds with inherent permeability potential during early discovery; and (2) post-screening structural refinement, covering rational design strategies including intramolecular hydrogen-bond (IMHB) shielding, “chameleonic” adaptations, and stimuli-responsive reversible stapling. Furthermore, we analyze the paradigm shift in assessment methodologies from qualitative imaging to quantitative cytosolic delivery assays, which have deepened our understanding of mechanisms such as the charge/lipophilicity threshold balance and metabolism-driven trapping. Overall, linker engineering provides a robust technical roadmap for developing the next generation of cell-permeable stapled peptide therapeutics. Full article

Monkeypox virus, a zoonotic DNA virus belonging to the Orthopoxvirus genus, has emerged as a global health issue because of its fast spread to 104 nations over six continents. In the current study, an immunoinformatics pipeline was used to design a multiepitope-based prophylactic vaccine targeting the A35R glycoprotein and E8L membrane proteins of the monkeypox virus. Selected target proteins were surface-exposed, non-homologous to the human proteome, and essential for viral pathogenesis. B-cell and T-cell (MHC-I and MHC-II) epitopes with high antigenicity (>0.5), non-allergenicity, non-toxicity, and highly soluble in water with strong affinity towards innate and adaptive receptors, were prioritized. Shortlisted epitopes were combined to design the final vaccine utilizing an adjuvant (50S ribosomal L7/L12) and appropriate linkers for improved immunogenicity. Population coverage analysis showed wide HLA representation with 83.57% (MHC-I) and 88.8% (MHC-II) global coverage, including 89.6% for West Africa and 87.3% for Central Africa. Docking analysis of the vaccine construct with the TLR-4 receptor revealed stable interactions (−695.6 kcal/mol). Molecular dynamics simulations and binding free energies further confirmed structural stability. Immune simulations predicted strong activation of both humoral and cellular immune responses. These results indicate that the designed multiepitope vaccine construct is a viable option for additional experimental validation against the monkeypox virus. Full article

Ochratoxin A (OTA) is a highly toxic mycotoxin commonly detected in food and agricultural products, requiring sensitive analytical methods for reliable monitoring. Herein, we report an ultrasensitive turn-on electrochemical aptasensor for OTA detection based on a target-induced displacement of an aptamer–complementary DNA (cDNA) duplex assembled on an electrochemically reduced graphene oxide (ERGO)-modified glassy carbon electrode (GCE). In the absence of OTA, a methylene blue (MB)-labeled aptamer hybridized with cDNA is immobilized on the ERGO surface via π–π stacking interactions, forming a rigid duplex that suppresses electron transfer and yields a low electrochemical signal. Upon OTA binding, the aptamer undergoes a conformational transition into a G-quadruplex structure, leading to dissociation of the cDNA strand. This target-induced folding brings the MB redox tag into close proximity to the ERGO surface, markedly accelerating electron transfer and enhancing the cathodic reduction current of MB, thereby producing a pronounced signal-on response in square-wave voltammetry (SWV). The ERGO-modified electrode provides a conductive and stable interface without chemical linkers. Under optimized conditions, the aptasensor shows a linear response to OTA from 10 fM to 100 pM with an ultralow LOD of 0.67 fM, together with high selectivity, good reproducibility, and satisfactory stability. This work demonstrates a simple and effective turn-on aptasensing strategy for sensitive electrochemical detection of OTA. Full article

Nuclear mechanics and mechanotransduction are involved in the migration and invasion process, such as those in which the cells need to deform themselves to pass through constrictions. Specifically, properties like nuclear softness, viscoelasticity, plasticity (like nuclear pore complexes) and deformability are critical in cancer and its malignant progression. The nucleus represents a physical barrier for the migration and invasion in dense 3D extracellular matrix (ECM) scaffolds. Therefore, the deformability of the nucleus seems to determine the migration limit in circumstances where the enzymatic remodeling of the surroundings is impaired. There are still significant knowledge gaps regarding effects of nuclear deformation during cancer dissemination. It seems that nuclear deformation can alter gene transcription, induce alternative splicing processes, impact nuclear envelope rupture, nuclear pore complex dilatation, damage the DNA, and increase the genomic instability. These mechanically induced alterations can in turn impact the migratory behavior of the cancer cells. The stiffness of the nucleus relies on the condensation of chromatin, and the nuclear lamina, which consists of a network of intermediate filaments underneath the nuclear envelope. All of this is discussed in the review and it is argued that nuclear deformability is universally found in various cancer types. Another focus is placed on the nuclear envelope proteins like emerin, and the SUN-KASH complex and how they contribute to the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex, which consequently couples the nucleus and the cytoskeleton. It is argued that this connection is crucial for force transmission, which governs nuclear stiffness dynamically, depending on the force applied. In this review, recent findings are described that couple ECM-induced nuclear mechanosensing and mechanotransduction with the migration and invasion of cancer cells. Moreover, it is suspected that changes in the mechanosensory characteristics of the cell nucleus could play a pivotal part in the malignancy of cancer cells and the heterogeneity of tumors. Finally, it is discussed what impact the individual elements of the nucleus offer to mechanically alter cellular migration and invasion in cancer and its malignant progression. Full article

We synthesized seven carbocyclic nucleoside analogs featuring a cyclopentane ring in place of the (deoxy)ribose sugar, which serves as a linker in DNA/RNA nucleosides. We assessed the stability of cyclopentane nucleosides in 98% w/w sulfuric acid at room temperature via ¹H and ¹³C NMR spectroscopy. We observe that adenine (A1, A4), guanine (G1) and thymine (T1) cyclopentane nucleoside analogs remain stable for at least two weeks at room temperature, with only minor (~4%) degradation in A1. In contrast, the cytosine analog (C1) rapidly degrades to release a soluble cytosine. Methyl-substituted adenine analogs mimicking polymer backbone attachments at positions prone to tertiary carbocation formation (A2, A3) prove unstable and release soluble adenine. Only the 3,3-dimethylcyclopentyl adenine analog (A4) exhibits sufficient stability. Our findings reveal that cyclopentane serves as a viable stable linker in concentrated sulfuric acid for select nucleic acid bases, provided that the backbone connections avoid tertiary carbons susceptible to carbocation-mediated cleavage. We thus identify one potential key structural feature for engineering examples of genetic-like polymers that could potentially persist in Venus’s concentrated sulfuric acid cloud environment. Full article

Ultrastructure changes in S. aureus and E. faecalis bacteria incubated with synthetic cationic amphiphile DL₄12 and its hybrids with the natural monoterpene carvacrol were studied. The hybrid compounds DL₄CAR-6, DL₅CAR-6, DLpCAR-6, and DLoCAR-6 contained two carvacrol molecules and differed in central linker structure. The study was conducted on ultrathin sections of bacteria fixed by the Ryter–Kellenberger method and on a Jem 1400 transmission electron microscope (Jeol, Tokyo, Japan). Ultrastructure changes in S. aureus and E. faecalis incubated with compound DL₄12 were species-specific. Destructive changes in S. aureus cells when exposed to DL₄12 compound and all DL₄12-carvacrol hybrids did not differ. DL₄12 and DL₄12-carvacrol hybrids in E. faecalis cells damaged all structures except the cell wall. Compound DL₄12 and its hybrids disrupted the ultrastructure of nucleoid and DNA strands in both bacterial species. Complete disorganization of ribosomes in cells of both bacteria occurred upon incubation with compound DL₄12 and its carvacrol-bearing analog DL₄CAR-6. Inclusions in bacterial cells exposed to all compounds had the same ultrastructure. The study showed that all compounds used possess multitarget properties; the structure of the central linker of hybrid compounds plays a significant role in the nature of their damaging effect on S. aureus and E. faecalis cells. Full article

In mitotic cell division, cytokinesis is followed by abscission, the final separation of the cytoplasmic canal, to release the two genetically identical daughter cells; however, sometimes chromatin bridges connecting the daughter nuclei appear. Preserving intact chromatin bridges is crucial because their breakage can cause DNA damage, aneuploidy, and cancer predisposition. For this purpose, cells use two main mechanisms: first, they activate the abscission checkpoint, a mechanism that delays the final cut of the cytoplasmic canal to prevent chromatin bridge breakage and secondly, they form accumulations of actin (“actin patches”) at the base of the intercellular canal to stabilize chromatin bridges. Here, we highlight new findings from our laboratory on how human cells “sense” chromatin bridges and remodel the actin cytoskeleton to generate actin patches in cytokinesis. More specifically, we discuss findings showing that the nuclear membrane Sun1/2-Nesprin-2-LINC (linker of nucleoskeleton and cytoskeleton) complex promotes the generation of mechanical tension on daughter nuclei with chromatin bridges. This tension leads to accumulation of Sun1/2 and Nesprin-2, and cytoplasmic accumulation of PDZ RhoGEF (PDZ domain-containing Rho guanine nucleotide exchange factor) at the base of the intercellular canal. In turn, PDZ RhoGEF activates downstream RhoA-ROCK-LIMK-Cofilin and RhoA-mDia1 signaling pathways to promote actin patches and prevent chromatin bridge breakage in cytokinesis. Full article

The past decade has witnessed an unprecedented transformation in breast cancer management, driven by parallel advances in targeted therapies, immunomodulation, drug-delivery technologies, and molecular diagnostic tools. This review summarizes the key achievements of 2015–2025, encompassing all major biological subtypes of breast cancer as well as technological innovations with substantial clinical relevance. In hormone receptor-positive (HR+)/HER2− disease, the integration of CDK4/6 inhibitors, modulators of the PI3K/AKT/mTOR pathway, oral Selective Estrogen Receptor Degraders (SERDs), and real-time monitoring of Estrogen Receptor 1 (ESR1) mutations has enabled clinicians to overcome endocrine resistance and dynamically tailor treatment based on evolving molecular alterations detected in circulating biomarkers. In HER2-positive breast cancer, treatment paradigms have been revolutionized by next-generation antibody–drug conjugates, advanced antibody formats, and technologies facilitating drug penetration across the blood–brain barrier, collectively improving systemic and central nervous system disease control. The most rapid progress has occurred in triple-negative breast cancer (TNBC), where synergistic strategies combining selective cytotoxicity via Antibody-Drug Conjugates (ADCs), DNA damage response inhibitors, immunotherapy, epigenetic modulation, and therapies targeting immunometabolic pathways have markedly expanded therapeutic opportunities for this historically challenging subtype. In parallel, photodynamic therapy has emerged as an investigational and predominantly local phototheranostic approach, incorporating nanocarriers, next-generation photosensitizers, and photoimmunotherapy capable of inducing immunogenic cell death and modulating antitumor immune responses. A defining feature of the past decade has been the surge in patent-driven innovation, encompassing multispecific antibodies, optimized ADC architectures, novel linker–payload designs, and advanced nanotechnological and photoactive delivery systems. By integrating data from clinical trials, molecular analyses, and patent landscapes, this review illustrates how multimechanistic, biomarker-guided therapies supported by advanced drug-delivery technologies are redefining contemporary precision oncology in breast cancer. The emerging therapeutic paradigm underscores the convergence of targeted therapy, immunomodulation, synthetic lethality, and localized immune-activating approaches, charting a path toward further personalization of treatment in the years ahead. Full article

Intrinsically disordered regions enable transcription factors (TFs) to undergo structural changes upon ligand binding, facilitating the transduction of environmental signals into gene expression. In this study, we applied molecular modeling methods to explore the hypothesis that unstructured inter-domain and subdomain linkers in bacterial TFs can function as sensors for carbohydrate signaling molecules. We combined molecular dynamics simulations and carbohydrate docking to analyze six repressors with GntR-type DNA-binding domains, including UxuR, GntR and FarR from Escherichia coli, as well as AraR, NagR and YydK from Bacillus subtilis. Protein models obtained from different time points of the dynamic simulations were subjected to sequential carbohydrate docking. We found that the inter-domain linker of the UxuR monomer binds D-fructuronate, D-galacturonate, D-glucose, and D-glucuronate with an affinity comparable to nonspecific interactions. However, these ligands formed multimolecular clusters, a feature absent in the UxuR dimer, suggesting that protein dimerization may depend on linker occupancy by cellular carbohydrates. D-glucose interacted with linkers connecting subdomains of the LacI/GalR-type E-domains in GntR and AraR, forming hydrogen bonds that connected distant structural modules of the proteins, while in NagR, FarR and YydK, it bridged the inter-domain linkers and a β-sheet within the HutC-type E-domains. Hence, our results establish flexible linkers as pivotal metabolic sensors that directly integrate nutritional cues to alter gene expression in bacteria. Full article

The SARS-CoV-2 nucleocapsid protein (Np) is essential for viral RNA replication and genomic RNA packaging. Phosphorylation of Np within its central Ser-Arg-rich (SRR) linker is proposed to modulate these functions. To gain mechanistic insights into these distinct roles, we performed in vitro biophysical and biochemical studies using recombinantly expressed ancestral Np and phosphomimetic SRR variants. Limited-proteolysis showed minor cleavage differences between wild-type (WT) and phosphomimetic Np, but no major structure or stability changes in the N- and C-terminal domains were observed by circular dichroism spectroscopy and differential scanning fluorimetry, respectively. Mass photometry (MP) revealed that WT Np dimerized more readily than phosphomimetic variants. Crosslinking-MP showed that WT Np formed discrete complexes on viral 5′ UTR stem-loop (SL) 5 RNA, whereas phosphomimetic Np assembled preferentially on SL1–4. WT Np bound non-specifically to all RNAs tested primarily via hydrophobic interactions, whereas phosphomimetic Np showed selectivity for SARS-CoV-2-derived RNAs despite binding more electrostatically. A major difference was observed in the binding kinetics; WT Np compacted and irreversibly bound single-stranded DNA, whereas phosphomimetic Np displayed reduced compaction and fast on/off binding kinetics. These mechanistic insights support a model where phosphorylated Np functions in RNA replication and chaperoning, while non-phosphorylated Np facilitates genomic RNA packaging. The findings also help to explain infectivity differences and clinical outcomes associated with SRR linker variants. Full article