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Background: Acquired resistance and adverse effects are some of the challenges faced by thousands of Luminal A breast cancer patients under tamoxifen (TMX) treatment. Some authors associate the overexpression of HOXB7 with TMX resistance in this molecular subtype, and the knockdown of this gene could be an effective strategy to regain TMX sensitivity. Therefore, we used calcium phosphate hybrid nanoparticles (HNP) for the delivery of short interfering RNA molecule (siRNA) complementary to the HOXB7 gene and evaluated the RNA interference (RNAi) effects associated with TMX treatment in breast cancer in vivo. Methods: HNP were prepared by the self-assembly of a methoxy-poly (ethylene glycol)-block-poly (L-glutamic acid) copolymer (PEG-pGlu) and the coprecipitation of CaPO4 to incorporate siRNA. The in vitro cell viability and migration were evaluated prior to in vivo experiments. Further, animals bearing early-stage and advanced Luminal A breast cancer were treated with HNP-siHOXB7, HNP-siHOXB7 + TMX, and TMX. Antitumoral activity and gene expression were evaluated following histopathological, hematological, and biochemical analysis. Results: The HNP were efficient in delivering the siRNA in vitro and in vivo, whilst HOXB7 silencing associated with TMX administration promoted controlled tumor growth, as well as a higher survival rate and reduction in immuno- and hepatotoxicity. Conclusions: Therefore, our findings suggest that HOXB7 can be an interesting molecular target for Luminal A breast cancer, especially associated with hormone therapy, aiming for adverse effect mitigation and higher therapeutic efficacy. [ABSTRACT FROM AUTHOR]

Lung cancer is the leading cause of cancer-related mortality worldwide, largely due to the limited efficacy of anticancer drugs, which is primarily attributed to insufficient doses reaching the lungs. Additionally, patients undergoing treatment experience severe systemic adverse effects due to the distribution of anticancer drugs to non-targeted sites. In light of these challenges, there has been a growing interest in pulmonary administration of drugs for the treatment of lung cancer. This route allows drugs to be delivered directly to the lungs, resulting in high local concentrations that can enhance antitumor efficacy while mitigating systemic toxic effects. However, pulmonary administration poses the challenge of overcoming the mechanical, chemical, and immunological defenses of the respiratory tract that prevent the inhaled drug from properly penetrating the lungs. To overcome these drawbacks, the use of nanoparticles in inhaler formulations may be a promising strategy. Nanoparticles can assist in minimizing drug clearance, increasing penetration into the lung epithelium, and enhancing cellular uptake. They can also facilitate increased drug stability, promote controlled drug release, and delivery to target sites, such as the tumor environment. Among them, chitosan-based nanoparticles demonstrate advantages over other polymeric nanocarriers due to their unique biological properties, including antitumor activity and mucoadhesive capacity. These properties have the potential to enhance the efficacy of the drug when administered via the pulmonary route. In view of the above, this paper provides an overview of the research conducted on the delivery of anticancer drug-loaded chitosan-based nanoparticles incorporated into inhaled drug delivery devices for the treatment of lung cancer. Furthermore, the article addresses the use of emerging technologies, such as siRNA (small interfering RNA), in the context of lung cancer therapy. Particularly, recent studies employing chitosan-based nanoparticles for siRNA delivery via the pulmonary route are described. [ABSTRACT FROM AUTHOR]

For efficient delivery of siRNA into the cytoplasm, a smart block copolymer of poly(ethylene glycol) and charge-conversion polymer (PEG-CCP) is developed by introducing 2-propionic-3-methylmaleic (PMM) amide as an anionic protective group into side chains of an endosome-disrupting cationic polyaspartamide derivative. The PMM amide moiety is highly susceptible to acid hydrolysis, generating the parent cationic polyaspartamide derivative at endosomal acidic pH 5.5 more rapidly than a previously synthesized cis-aconitic (ACO) amide control. The PMM-based polymer is successfully integrated into a calcium phosphate (CaP) nanoparticle with siRNA, constructing PEGylated hybrid micelles (PMM micelles) having a sub-100 nm size at extracellular neutral pH 7.4. Ultimately, PMM micelles achieve the significantly higher gene silencing efficiency in cultured cancer cells, compared to ACO control micelles, probably due to the efficient endosomal escape of the PMM micelles. Thus, it is demonstrated that fine-tuning of acid-labile structures in CCP improves the delivery performance of siRNA-loaded nanocarriers. [ABSTRACT FROM AUTHOR]

Abstract: Development of an efficient in vivo delivery vehicle of small interfering RNA (siRNA) is the key challenge for successful siRNA-based therapies. In this study, toward systemic delivery of siRNA to solid tumors, a smart polymer/calcium phosphate (CaP)/siRNA hybrid nanoparticle was prepared to feature biocompatibility, reversible stability and endosomal escape functionality using a pH sensitive block copolymer of poly(ethylene glycol) and charge-conversional polymer (PEG-CCP), of which anionic functional groups could be converted to cationic groups in an endosomal acidic condition for facilitated endosomal escape. Nanoparticles were confirmed to be approximately 100nm in size, narrowly dispersed and spherical. Also, the nanoparticle was highly tolerable in medium containing serum, while releasing the entrapped siRNA in a cytoplasm-mimicking ionic condition, presumably based on the equilibrium between CaP complexes and calcium ions. Further, the nanoparticle showed high gene silencing efficiency in cultured pancreatic cancer cells (BxPC3) without associated cytotoxicity. Ultimately, systemic administration of the nanoparticles carrying vascular endothelium growth factor (VEGF) siRNA led to the significant reduction in the subcutaneous BxPC3 tumor growth, well consistent with the enhanced accumulation of siRNA and the significant VEGF gene silencing (~68%) in the tumor. Thus, the hybrid nanoparticle was demonstrated to be a promising formulation toward siRNA-based cancer therapies. [Copyright &y& Elsevier]

Abstract: Development of safe and efficient short interfering RNA (siRNA) delivery system for RNA interference (RNAi)-based therapeutics is a current critical challenge in drug delivery field. The major barriers in siRNA delivery into the target cytoplasm are the fragility of siRNA in the body, the inefficient cellular uptake, and the acidic endosomal entrapment. To overcome these barriers, this study is presenting a hybrid nanocarrier system composed of calcium phosphate comprising the block copolymer of poly(ethylene glycol) (PEG) and charge-conversional polymer (CCP) as a siRNA vehicle. In these nanoparticles, the calcium phosphate forms a stable core to incorporate polyanions, siRNA and PEG–CCP. The synthesized PEG–CCP is a non-toxic endosomal escaping unit, which induces endosomal membrane destabilization by the produced polycation through degradation of the flanking cis-aconitylamide of CCP in acidic endosomes. The nanoparticles prepared by mixing of each component was confirmed to possess excellent siRNA-loading efficiency (∼80% of dose), and to present relatively homogenous spherical shape with small size. With negligible cytotoxicity, the nanoparticles efficiently induced vascular endothelial growth factor (VEGF) mRNA knockdown (∼80%) in pancreatic cancer cells (PanC-1). Confocal laser scanning microscopic observation revealed rapid endosomal escape of siRNA with the nanoparticles for the excellent mRNA knockdown. The results obtained demonstrate our hybrid nanoparticle as a promising candidate to develop siRNA therapy. [Copyright &y& Elsevier]

Since the possibility of silencing specific genes linked to retinal degeneration has become a reality with the use of small interfering RNAs (siRNAs), this technology has been widely studied to promote the treatment of several ocular diseases. Despite recent advances, the clinical success of gene silencing in the retina is significantly reduced by inherent anatomical and physiological ocular barriers, and new strategies are required to achieve intraocular therapeutic effectiveness. In this study, we developed lipoplexes, prepared with sodium alginate as an adjuvant and strategically coated with hyaluronic acid (HA-LIP), and investigated the potential neuroprotective effect of these systems in a retinal light damage model. Successful functionalization of the lipoplexes with hyaluronic acid was indicated in the dynamic light scattering and transmission electron microscopy results. Moreover, these HA-LIP nanoparticles were able to protect and deliver siRNA molecules targeting caspase-3 into the retina. After retinal degeneration induced by high light exposure, in vitro and in vivo quantitative reverse transcription-PCR (RT-qPCR) assays demonstrated significant inhibition of caspase-3 expression by HA-LIP. Furthermore, these systems were shown to be safe, as no evidence of retinal toxicity was observed by electroretinography, clinical evaluation or histology. [ABSTRACT FROM AUTHOR]

Breast cancer is a major cause of death among women worldwide. Resistance to conventional therapies has been observed in HER2-positive breast cancer patients, indicating the need for more effective treatments. Small interfering RNA (siRNA) therapy is an attractive strategy against HER2-positive tumors, but its success depends largely on the efficient delivery of agents to target tissues. In this study, we prepared a magnetic hybrid nanostructure composed of iron oxide nanoparticles coated with caffeic acid and stabilized by layers of calcium phosphate and PEG-polyanion block copolymer for incorporation of siRNA. Transmission electron microscopy images showed monodisperse, neutrally charged compact spheres sized <100 nm. Dynamic light scattering and nanoparticle tracking analysis revealed that the nanostructure had an average hydrodynamic diameter of 130 nm. Nanoparticle suspensions remained stable over 42 days of storage at 4 and 25 °C. Unloaded caffeic acid–magnetic calcium phosphate (Caf-MCaP) nanoparticles were not cytotoxic, and loaded nanoparticles were successfully taken up by the HER2-positive breast cancer cell line HCC1954, even more so under magnetic guidance. Nanoparticles escaped endosomal degradation and delivered siRNA into the cytoplasm, inducing HER2 gene silencing. • Nanoparticles delivered the siRNA after endosomal escape. • Caf-MCaPs presented no cytotoxicity. • Caf-MCaPs were taken up efficiently by the HER2-positive breast cancer cell line HCC1954. • Caf-MCaPs were taken up efficiently by HCC1954 cells, enhanced after magnetic guidance. [ABSTRACT FROM AUTHOR]