Nucleolin aptamer conjugated MSNPs-PLR-PEG multifunctional nanoconstructs for targeted co-delivery of anticancer drug and siRNA to counter drug resistance in TNBC

Stimuli-Responsive Aptamer-Drug Conjugates for Targeted Drug Delivery and Controlled Drug Release

Chemotherapy is widely used for cancer therapy but with unsatisfied efficacy, mainly due to the inefficient delivery of anticancer agents. Among the critical "five steps" drug delivery process, internalization into tumor cells and intracellular drug release are two important steps for the overall therapeutic efficiency. Strategy based on active targeting or TME-responsive is developed individually to improve therapeutic efficiency, but with limited improvement. However, the combination of these two strategies could potentially augment the drug delivery efficiency and therapeutic efficiency, consequently. Therefore, this work constructs a library of stimuli-responsive aptamer-drug conjugates (srApDCs), as "dual-targeted" strategy for cancer treatment that enables targeted drug delivery and controlled drug release. Specifically, this work uses different stimuli-responsive linkers to conjugate a tumor-targeting aptamer (i.e., AS1411) with drugs, forming the library of srApDCs for targeted cancer treatment. This design hypothesis is validated by the experimental data, which indicated that the aptamer could selectively enhance uptake of the srApDCs and the linkers could be cleaved by pathological cues in the TME to release the drug payload, leading to a significant enhancement of therapeutic efficacy. These results underscore the potential of the approach, providing a promising methodology for cancer therapy.

Recent Progress of Multifunctional Molecular Probes for Triple-Negative Breast Cancer Theranostics

Breast cancer (BC) poses a significant threat to women's health, with triple-negative breast cancer (TNBC) representing one of the most challenging and aggressive subtypes due to the lack of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression. Traditional TNBC treatments often encounter issues such as low drug efficiency, limited tumor enrichment, and substantial side effects. Therefore, it is crucial to explore novel diagnostic and treatment systems for TNBC. Multifunctional molecular probes (MMPs), which integrate target recognition as well as diagnostic and therapeutic functions, introduce advanced molecular tools for TNBC theranostics. Using an MMP system, molecular drugs can be precisely delivered to the tumor site through a targeted ligand. Real-time dynamic monitoring of drug release achieved using imaging technology allows for the evaluation of drug enrichment at the tumor site. This approach enables accurate drug release, thereby improving the therapeutic effect. Therefore, this review summarizes the recent advancements in MMPs for TNBC theranostics, encompassing the design and synthesis of MMPs as well as their applications in the field of TNBC theranostics.

MUC1 aptamer-tethered H40-TEPA-PEG nanoconjugates for targeted siRNA-delivery and gene silencing in breast cancer cells

With a prevalence of 12.5% of all new cancer cases annually, breast cancer stands as the most common form of cancer worldwide. The current therapies utilized for breast cancer are constrained and ineffective in addressing the condition. siRNA-based gene silencing is a promising method for treating breast cancer. We have developed an aptamer-conjugated dendritic multilayered nanoconjugate to treat breast cancer. Initially, we transformed the hydroxyl groups of the hyperbranched bis-MPA polyester dendrimer into carboxylic groups. Subsequently, we linked these carboxylic groups to tetraethylenepentamine to form a positively charged dendrimer. In addition, the mucin-1 (MUC1) aptamer was attached to the dendrimer using a heterobifunctional polyethylene glycol. Characterizing dendrimers involved 1H NMR and dynamic light scattering techniques at every production stage. A gel retardation experiment was conducted to evaluate the successful binding of siRNA with targeted and non-targeted dendrimers. The targeted dendrimers exhibited no harmful effects on the NIH-3T3 fibroblast cells and RBCs, indicating their biocompatible characteristics. Confocal microscopy demonstrated significant higher uptake of targeted dendrimers than non-targeted dendrimers in MCF-7 breast cancer cells. The real-time PCR results demonstrated that the targeted dendrimers exhibited the most pronounced inhibition of the target gene expression compared to the non-targeted dendrimers and lipofectamine-2000. The caspase activation study confirmed the functional effect of survivin silencing by dendrimer, which led to the induction of apoptosis in breast cancer cells. The findings indicated that Mucin-1 targeted hyperbranched bis-MPA polyester dendrimer carrying siRNA could successfully suppress the expression of the target gene in breast cancer cells.

Targeting triple negative breast cancer stem cells using nanocarriers

Breast cancer is a complex and heterogeneous disease, encompassing various subtypes characterized by distinct molecular features, clinical behaviors, and treatment responses. Categorization of subtypes is based on the presence or absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), leading to subtypes such as luminal A, luminal B, HER2-positive, and triple-negative breast cancer (TNBC). TNBC, comprising around 20% of all breast cancers, lacks expression of ER, PR, and HER2 receptors, rendering it unresponsive to targeted therapies and presenting significant challenges in treatment. TNBC is associated with aggressive behavior, high rates of recurrence, and resistance to chemotherapy. Tumor initiation, progression, and treatment resistance in TNBC are attributed to breast cancer stem cells (BCSCs), which possess self-renewal, differentiation, and tumorigenic potential. Surface markers, self-renewal pathways (Notch, Wnt, Hedgehog signaling), apoptotic protein (Bcl-2), angiogenesis inhibition (VEGF inhibitors), and immune modulation (cytokines, immune checkpoint inhibitors) are among the key targets discussed in this review. However, targeting the BCSC subpopulation in TNBC presents challenges, including off-target effects, low solubility, and bioavailability of anti-BCSC agents. Nanoparticle-based therapies offer a promising approach to target various molecular pathways and cellular processes implicated in survival of BSCS in TNBC. In this review, we explore various nanocarrier-based approaches for targeting BCSCs in TNBC, aiming to overcome these challenges and improve treatment outcomes for TNBC patients. These nanoparticle-based therapeutic strategies hold promise for addressing the therapeutic gap in TNBC treatment by delivering targeted therapies to BCSCs while minimizing systemic toxicity and enhancing treatment efficacy.

TfR Aptamer-Functionalized MSNs for Enhancing Targeted Cellular Uptake and Therapy of Cancer Cells

Mesoporous silica nanoparticles (MSNs), as novel nanocarriers for drug delivery in cancer treatment, have attracted widespread concern because of their rich pore structure, large pore capacity, ease of modification, and biocompatibility. However, the limitation of nontargeting and low uptake efficiency hindered their further application. Considering the overexpression of the transferrin receptor (TfR) on most cancer cell membranes, herein, we propose a strategy to effectively enhance the cellular internalization of MSNs by arming them with the TfR aptamer. Cellular fluorescent imaging and flow cytometry analysis demonstrated that TfR aptamer-functionalized MSNs exhibited superior cellular internalization compared to unmodified or random sequence-modified MSNs toward three different cancer cell lines, including MCF-7, HeLa, and A549. Furthermore, TfR aptamer-functionalized MSNs displayed enhanced drug delivery efficiency compared with MSNs at equivalent doses and incubation times. These results suggested that TfR aptamer-functionalized MSNs have the potential for enhanced delivery of therapeutic agents into TfR-positive cancer cells to improve therapeutic efficacy.

A Comprehensive Review of Small Interfering RNAs (siRNAs): Mechanism, Therapeutic Targets, and Delivery Strategies for Cancer Therapy

Small interfering RNA (siRNA) delivery by nanocarriers has been identified as a promising strategy in the study and treatment of cancer. Short nucleotide sequences are synthesized exogenously to create siRNA, which triggers RNA interference (RNAi) in cells and silences target gene expression in a sequence-specific way. As a nucleic acid-based medicine that has gained popularity recently, siRNA exhibits novel potential for the treatment of cancer. However, there are still many obstacles to overcome before clinical siRNA delivery devices can be developed. In this review, we discuss prospective targets for siRNA drug design, explain siRNA drug properties and benefits, and give an overview of the current clinical siRNA therapeutics for the treatment of cancer. Additionally, we introduce the siRNA chemical modifications and delivery systems that are clinically sophisticated and classify bioresponsive materials for siRNA release in a methodical manner. This review will serve as a reference for researchers in developing more precise and efficient targeted delivery systems, promoting ongoing advances in clinical applications.

Recent Advances in Mesoporous Silica Nanoparticles Delivering siRNA for Cancer Treatment

Silencing genes using small interfering (si) RNA is a promising strategy for treating cancer. However, the curative effect of siRNA is severely constrained by low serum stability and cell membrane permeability. Therefore, improving the delivery efficiency of siRNA for cancer treatment is a research hotspot. Recently, mesoporous silica nanoparticles (MSNs) have emerged as bright delivery vehicles for nucleic acid drugs. A comprehensive understanding of the design of MSN-based vectors is crucial for the application of siRNA in cancer therapy. We discuss several surface-functionalized MSNs' advancements as effective siRNA delivery vehicles in this paper. The advantages of using MSNs for siRNA loading regarding considerations of different shapes, various options for surface functionalization, and customizable pore sizes are highlighted. We discuss the recent investigations into strategies that efficiently improve cellular uptake, facilitate endosomal escape, and promote cargo dissociation from the MSNs for enhanced intracellular siRNA delivery. Also, particular attention was paid to the exciting progress made by combining RNAi with other therapies to improve cancer therapeutic outcomes.

Lipid polymer hybrid nanoparticles: a custom-tailored next-generation approach for cancer therapeutics

Lipid-based polymeric nanoparticles are the highly popular carrier systems for cancer drug therapy. But presently, detailed investigations have revealed their flaws as drug delivery carriers. Lipid polymer hybrid nanoparticles (LPHNPs) are advanced core-shell nanoconstructs with a polymeric core region enclosed by a lipidic layer, presumed to be derived from both liposomes and polymeric nanounits. This unique concept is of utmost importance as a combinable drug delivery platform in oncology due to its dual structured character. To add advantage and restrict one's limitation by other, LPHNPs have been designed so to gain number of advantages such as stability, high loading of cargo, increased biocompatibility, rate-limiting controlled release, and elevated drug half-lives as well as therapeutic effectiveness while minimizing their drawbacks. The outer shell, in particular, can be functionalized in a variety of ways with stimuli-responsive moieties and ligands to provide intelligent holding and for active targeting of antineoplastic medicines, transport of genes, and theragnostic. This review comprehensively provides insight into recent substantial advancements in developing strategies for treating various cancer using LPHNPs. The bioactivity assessment factors have also been highlighted with a discussion of LPHNPs future clinical prospects.

Advanced cancer targeting using aptamer functionalized nanocarriers for site-specific cargo delivery

The non-specificity of standard anticancer therapies has profound detrimental consequences in clinical treatment. Therapeutic specificity can be precisely achieved using cutting-edge ligands. Small synthetic oligonucleotide-ligands chosen through Systematic evolution of ligands by exponential enrichment (SELEX) would be an unceasing innovation in using nucleic acids as aptamers, frequently referred to as "chemical antibodies." Aptamers act as externally controlled switching materials that can attach to various substrates, for example, membrane proteins or nucleic acid structures. Aptamers pose excellent specificity and affinity for target molecules and can be used as medicines to suppress tumor cell growth directly. The creation of aptamer-conjugated nanoconstructs has recently opened up innovative options in cancer therapy that are more effective and target tumor cells with minor toxicity to healthy tissues. This review focuses on a comprehensive description of the most capable classes of aptamer-tethered nanocarriers for precise recognition of cancer cells with significant development in proficiency, selectivity, and targetability for cancer therapy. Existing theranostic applications with the problems and future directions are also highlighted.

Application of aptamer-drug delivery system in the therapy of breast cancer

Despite significant treatment advances, breast cancer remains the leading cause of cancer death in women. From the current treatment situation, in addition to developing chemoresistant tumours, distant organ metastasis, and recurrences, patients with breast cancer often have a poor prognosis. Aptamers as "chemical antibodies" may be a way to resolve this dilemma. Aptamers are single-stranded, non-coding oligonucleotides (DNA or RNA), resulting their many advantages, including stability for long-term storage, simplicity of synthesis and function, and low immunogenicity, a high degree of specificity and antidote. Aptamers have gained popularity as a method for diagnosing and treating specific tumors in recent years. This article introduces the application of ten different aptamer delivery systems in the treatment and diagnosis of breast cancer, and systematically reviews their latest research progress in breast cancer treatment and diagnosis. It provides a new direction for the clinical treatment of breast cancer.