Molecular Mechanism for Selective Cytotoxicity towards Cancer Cells of Diselenide-Containing Paclitaxel Nanoparticles

Cross-Talk Between Selenium Nanoparticles and Cancer Treatment Through Autophagy

Autophagy is commonly referred as self-eating and a complex cellular process that is involved in the digestion of protein and damaged organelles through a lysosome-dependent mechanism, and this mechanism is essential for maintaining proper cellular homeostasis. Selenium is a vital trace element that plays essential functions in antioxidant defense, redox state control, and range of particular metabolic processes. Selenium nanoparticles have become known as a promising agent for biomedical use, because of their high bioavailability, low toxicity, and degradability. However, and in recent years, they have attracted the interest of researchers in developing anticancer nano-drugs. Selenium nanoparticles can be used as a potential therapeutic agent or in combination with other agents to act as carriers for the development of new treatments. More intriguingly, selenium nanoparticles have been extensively shown to impact autophagy signaling, allowing selenium nanoparticles to be used as possible cancer treatment agents. This review explored the connections between selenium and autophagy, followed by developments and current advances of selenium nanoparticles for autophagy control in various clinical circumstances. Furthermore, this study examined the functions and possible processes of selenium nanoparticles in autophagy regulation, which may help us understand how selenium nanoparticles regulate autophagy for the potential cancer treatment.

Co-Delivery of an Innovative Organoselenium Compound and Paclitaxel by pH-Responsive PCL Nanoparticles to Synergistically Overcome Multidrug Resistance in Cancer

In this study, we designed the association of the organoselenium compound 5'-Seleno-(phenyl)-3'-(ferulic-amido)-thymidine (AFAT-Se), a promising innovative nucleoside analogue, with the antitumor drug paclitaxel, in poly(ε-caprolactone) (PCL)-based nanoparticles (NPs). The nanoprecipitation method was used, adding the lysine-based surfactant, 77KS, as a pH-responsive adjuvant. The physicochemical properties presented by the proposed NPs were consistent with expectations. The co-nanoencapsulation of the bioactive compounds maintained the antioxidant activity of the association and evidenced greater antiproliferative activity in the resistant/MDR tumor cell line NCI/ADR-RES, both in the monolayer/two-dimensional (2D) and in the spheroid/three-dimensional (3D) assays. Hemocompatibility studies indicated the safety of the nanoformulation, corroborating the ability to spare non-tumor 3T3 cells and human mononuclear cells of peripheral blood (PBMCs) from cytotoxic effects, indicating its selectivity for the cancerous cells. Furthermore, the synergistic antiproliferative effect was found for both the association of free compounds and the co-encapsulated formulation. These findings highlight the antitumor potential of combining these bioactives, and the proposed nanoformulation as a potentially safe and effective strategy to overcome multidrug resistance in cancer therapy.

Radiation responsive PROTAC nanoparticles for tumor-specific proteolysis enhanced radiotherapy

Proteolysis targeting chimeras (PROTACs) is a promising strategy for cancer therapy. However, the always-on bioactivity of PROTACs may lead to non-target toxicity, which restricts their antitumor performance. Here, we developed an X-ray radiation responsive PROTAC nanomicelle (RCNprotac) by covalently conjugating a reported small molecule PROTAC (MZ1) to hydrophilic PEG via a diselenide bond-containing carbon chain, which then self-assembled into a 141.80 ± 5.66 nm nanomicelle. The RCNprotac displayed no bioactivity during circulation due to the occupation of the hydroxyl group on the E3 ubiquitin ligand component and could effectively accumulate at the tumor site owing to the enhanced permeability and retention effect. Upon exposure to X-ray radiation, the radiation-sensitive diselenide bonds were broken to specifically release MZ1 for tumor BRD4 protein degradation. Furthermore, the reduction in the BRD4 protein level could increase the tumor's sensitivity to radiation. RCNprotac showed a synergistic enhancement of antitumor effects both in vitro and in vivo. We believe that this X-ray-responsive PROTAC nanomicelle could provide a new strategy for the X-ray-activated spatiotemporally controlled protein degradation and for the BRD4 proteolysis enhanced tumor radiosensitivity.

Trends and recent progresses of selenium nanoparticles as novel autophagy regulators for therapeutic development

Autophagy, one of the major intracellular degradation systems, plays an important role in maintaining normal cellular physiological functions and protecting organisms from different diseases. Selenium (Se), an essential trace element, is involved in many metabolic regulatory signaling events and plays a key role in human health. In recent years, selenium nanoparticles (Se NPs) have attracted increasing attentions in biomedical field due to their low toxicity, high bioavailability and high bioactivity. Taking the advantage of their advanced biological activities, Se NPs can be used alone as potential therapeutic agents, or combine with other agents and served as carriers for the development of novel therapeutics. More interestingly, Se NPs have been widely reported to affect autophagy signaling, which therefor allow Se NPs to be used as potential therapeutic agents against different diseases. Here, this review suggested the relationships between Se and autophagy, followed by the trends and recent progresses of Se NPs for autophagy regulation in different diseased conditions. More importantly, this work discussed the roles and potential mechanisms of Se NPs in autophagy regulating, which might enhance our understanding about how Se NPs regulate autophagy for potential disease treatment. This work is expected to promote the potential application of Se NPs as novel autophagy regulators, which might benefit the development of novel autophagy associated therapeutics.

Ruthenium Complex HB324 Induces Apoptosis via Mitochondrial Pathway with an Upregulation of Harakiri and Overcomes Cisplatin Resistance in Neuroblastoma Cells In Vitro

Ruthenium(II) complexes with N-heterocyclic carbene (NHC) ligands have recently attracted attention as novel chemotherapeutic agents. The complex HB324 was intensively studied as an apoptosis-inducing compound in resistant cell lines. HB324 induced apoptosis via mitochondrial pathways. Of particular interest is the upregulation of the Harakiri resistance protein, which inhibits the anti-apoptotic and death repressor proteins Bcl-2 (B-cell lymphoma 2) and BCL-xL (B-cell lymphoma-extra large). Moreover, HB324 showed synergistic activity with various established anticancer drugs and overcame resistance in several cell lines, such as neuroblastoma cells. In conclusion, HB324 showed promising potential as a novel anticancer agent in vitro, suggesting further investigations on this and other preclinical ruthenium drug candidates.

Paclitaxel-loaded cubosome lipid nanocarriers stabilised with pH and hydrogen peroxide-responsive steric stabilisers as drug delivery vehicles

Responsive nanoparticle delivery systems hold great potential for next-generation chemotherapeutic treatment with reduced off-target side effects. In this work, we formulated responsive lipid-based cubosomes loaded with paclitaxel (PTX) as a model drug and stabilised by novel amphiphilic block copolymers (ABCs) containing the pH-responsive poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and/or the hydrogen peroxide (H₂O₂)-responsive poly(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl acrylate) (PTBA) blocks. The results showed that these cubosomes with a particle size of around 250 nm exhibited excellent PTX encapsulation efficiency of up to 60% and had the ability to control the release rate of the drug in response to pH and H₂O₂ changes. Specifically, compared to the physiological pH of 7.4, PTX was released faster from the cubosome carriers when exposed to pH 5.5 and/or 50 mM H₂O₂ conditions, which are pathological conditions found in a tumour microenvironment. In vitro cytotoxicity and cell uptake studies further investigated the cellular interactions of these cubosomes. It was found that cubosomes containing PTX had more toxic effects than the control free PTX sample. Compared to cubosomes stabilised by the non-responsive block copolymer Pluronic® F127, the ABC-stabilised cubosomes also had higher cell internalisation efficiency demonstrated by the cytoplasmic fluorescence intensities using confocal microscopy. These results demonstrated that ABCs containing responsive moieties can stabilise lipid cubosomes and enhance controlled release of poorly soluble chemotherapeutics and cellular uptake.

Tennis Rehabilitation Training-Assisted Paclitaxel Nanoparticles in Treatment of Lung Tumor

Paclitaxel nanoparticles are a compound with unique anticancer effects. Its mechanism of action is to prevent tumor rupture by stabilizing tumor proteins, while preventing cell division, leading to cell death, thereby inhibiting the spread of lung tumors. This article aims to study the treatment of lung tumors with paclitaxel nanoparticles assisted by tennis rehabilitation training. In this paper, paclitaxel nanoparticles were prepared by a solvent displacement method, and their particle size and morphology were measured. The TA2 series of experimental rats were selected to establish animal lung tumor models, and they were randomly divided into 5 groups: local injection of saline, porphyrin, and low-, medium-, and high-dose paclitaxel nanoparticles for treatment. The experimental results in this paper show that the average particle size of the paclitaxel nanoparticles prepared in the experiment is about 153,54 nm. Each treatment group inhibited tumor development to varying degrees. Among them, the inhibitory volume rate of paclitaxel nanoparticles in the middle- and high-dose groups was significantly higher than that in the paclitaxel treatment group, indicating that paclitaxel nanoparticles can release drugs slowly.

Probing the Superiority of Diselenium Bond on Docetaxel Dimeric Prodrug Nanoassemblies: Small Roles Taking Big Responsibilities

The current state of chemotherapy is far from satisfaction, restricted by the inefficient drug delivery and the off-target toxicity. Prodrug nanoassemblies are emerging as efficient platforms for chemotherapy. Herein, three docetaxel dimeric prodrugs are designed using diselenide bond, disulfide bond, or dicarbide bond as linkages. Interestingly, diselenide bond-bridged dimeric prodrug can self-assemble into stable nanoparticles with impressive high drug loading (≈70%, w/w). Compared with disulfide bond and dicarbide bond, diselenide bond greatly facilitates the self-assembly of dimeric prodrug, and then improves the colloidal stability, blood circulation time, and antitumor efficacy of prodrug nanoassemblies. Furthermore, the redox-sensitive diselenide bond can specifically respond to the overexpressed reactive oxygen species and glutathione in tumor cells, leading to tumor-specific drug release. Therefore, diselenide bond bridged prodrug nanoassemblies exhibit discriminating cytotoxicity between tumor cells and normal cells, significantly alleviating the systemic toxicity of docetaxel. The present work gains in-depth insight into the impact of diselenide bond on the dimeric prodrug nanoassemblies, and provides promising strategies for the rational design of the high efficiency-low toxicity chemotherapeutical nanomedicines.

Enhanced targeted delivery of adenine to hepatocellular carcinoma using glycyrrhetinic acid-functionalized nanoparticles in vivo and in vitro

Hepatocellular carcinoma (HCC), a common malignancy in China and globally, is primarily treated through surgical resection and liver transplantation, with chemotherapy as a significant synergistic option. Adenine (Ade), a nucleobase, exhibits antitumor effects by blocking human hepatic carcinoma cells in S phase and inhibiting tumor cell proliferation. However, its use is limited owing to its low solubility, poor targeting ability, and nephrotoxicity. Therefore, liver-targeting drug delivery systems have attracted considerable attention for the treatment of HCC. In this study, we explored the liver-targeting efficacy and antitumor effect of adenine-loaded glycyrrhetinic acid-modified hyaluronic acid (Ade/GA-HA) nanoparticles in vitro and in vivo. The GA-HA nanoparticles possessed obvious targeting specificity toward liver cancer cells, which was mainly achieved by the specific binding of the GA ligand to the GA receptor that was highly expressed on the liver cell membrane. In vitro and in vivo results showed that Ade/GA-HA nanoparticles could inhibit liver cancer cell proliferation and migration, promote apoptosis, and significantly inhibit the growth of tumor tissues. Altogether, this study is the first to successfully demonstrate that the targeting activity and antitumor effect of Ade against HCC are enhanced by using GA-HA nanoparticles in vitro and in vivo.