L-Se-methylselenocysteine sensitizes lung carcinoma to chemotherapy

Se-methylselenocysteine inhibits the progression of non-small cell lung cancer via ROS-mediated NF-κB signaling pathway

Se-methylselenocysteine (MSC) is recognized for its potential in cancer prevention, yet the specific effects and underlying processes it initiates within non-small cell lung cancer (NSCLC) remain to be fully delineated. Employing a comprehensive array of assays, including CCK-8, colony formation, flow cytometry, MitoSOX Red staining, wound healing, transwell, and TUNEL staining, we evaluated MSC's effects on A549 and 95D cell lines. Our investigation extended to the ROS-mediated NF-κB signaling pathway, utilizing Western blot analysis, P65 overexpression, and the application of IκB-α inhibitor (BAY11-7082) or N-acetyl-cysteine (NAC) to elucidate MSC's mechanism of action. In vivo studies involving subcutaneous xenografts in mice further confirmed MSC's inhibitory effect on tumor growth. Our findings indicated that MSC inhibited the proliferation of A549 and 95D cells, arresting cell cycle G0/G1 phase and reducing migration and invasion, while also inducing apoptosis and increasing intracellular ROS levels. This was accompanied by modulation of key proteins, including the upregulation of p21, p53, E-cadherin, Bax, cleaved caspase-3, cleaved-PARP, and downregulation of CDK4, SOD2, GPX-1. MSC was found to inhibit the NF-κB pathway, as evidenced by decreased levels of P-P65 and P-IκBα. Notably, overexpression of P65 and modulation of ROS levels with NAC could attenuate MSC's effects on cellular proliferation and metastasis. Moreover, MSC significantly curtailed tumor growth in vivo and disrupted the NF-κB signaling pathway. In conclusion, our research demonstrates that MSC exhibits anticancer effects against NSCLC by modulating the ROS/NF-κB signaling pathway, suggesting its potential as a therapeutic agent in NSCLC treatment.

Seleno-amino Acid Metabolism Reshapes the Tumor Microenvironment: from Cytotoxicity to Immunotherapy

Selenium (Se) is an essential trace element for biological processes. Seleno-amino acids (Se-AAs), known as the organic forms of Se, and their metabolic reprogramming have been increasingly recognized to regulate antioxidant defense, enzyme activity, and tumorigenesis. Therefore, there is emerging interest in exploring the potential application of Se-AAs in antitumor therapy. In addition to playing a vital role in inhibiting tumor growth, accumulating evidence has revealed that Se-AA metabolism could reshape the tumor microenvironment (TME) and enhance immunotherapy responses. This review presents a comprehensive overview of the current progress in multifunctional Se-AAs for antitumor treatment, with a particular emphasis on elucidating the crosstalk between Se-AA metabolism and various cell types in the TME, including tumor cells, T cells, macrophages, and natural killer cells. Furthermore, novel applications integrating Se-AAs are also discussed alongside prospects to provide new insights into this emerging field.

Se-methylselenocysteine ameliorates mitochondrial function by targeting both mitophagy and autophagy in the mouse model of Alzheimer's disease

Background: Alzheimer's disease (AD) exerts tremendous pressure on families and society due to its unknown etiology and lack of effective treatment options. Our previous study had shown that Se-methylselenocysteine (SMC) improved the cognition and synaptic plasticity of triple-transgenic AD (3 × Tg-AD) mice and alleviated the related pathological indicators. We are dedicated to investigating the therapeutic effects and molecular mechanisms of SMC on mitochondrial function in 3 × Tg-AD mice. Methods: Transmission electron microscopy (TEM), western blotting (WB), mitochondrial membrane potential (ΔΨm), mitochondrial swelling test, and mitochondrial oxygen consumption test were used to evaluate the mitochondrial morphology and function. Mitophagy flux and autophagy flux were assessed with immunofluorescence, TEM and WB. The Morris water maze test was applied to detect the behavioral ability of mice. Results: The destroyed mitochondrial morphology and function were repaired by SMC through ameliorating mitochondrial energy metabolism, mitochondrial biogenesis and mitochondrial fusion/fission balance in 3 × Tg-AD mice. In addition, SMC ameliorated mitochondria by activating mitophagy flux via the BNIP3/NIX pathway and triggering autophagy flux by suppressing the Ras/Raf/MEK/ERK/mTOR pathway. SMC remarkably increased the cognitive ability of AD mice. Conclusions: This research indicated that SMC might exert its therapeutic effect by protecting mitochondria in 3 × Tg-AD mice.

Preventing acute liver injury via hepatocyte-targeting nano-antioxidants

Acute liver injury (ALI) is a severe liver disease that is characterized by sudden and massive hepatocyte necrosis and deterioration of liver functions. Oxidative stress is increasingly recognized as a key factor in the induction and progression of ALI. Scavenging excessive reactive oxygen species (ROS) with antioxidants has become a promising therapeutic option, but intrinsically hepatocyte-targeting antioxidants with excellent bioavailability and biocompatibility are yet to be developed. Herein, self-assembling nanoparticles (NPs) composed of amphiphilic polymers are introduced to encapsulate organic Selenium compound L-Se-methylselenocysteine (SeMC) and form SeMC NPs, which protect the viabilities and functions of cultured hepatocytes in drug- or chemical-induced acute hepatotoxicity models via efficient ROS removal. After further functionalization with the hepatocyte-targeting ligand glycyrrhetinic acid (GA), the resultant GA-SeMC NPs exhibit enhanced hepatocyte uptake and liver accumulation. In mouse models of ALI induced by acetaminophen (APAP) or carbon tetrachloride (CCl4 ), treatment with GA-SeMC NPs significantly decrease the levels of hepatic lipid peroxidation, tissue vacuolization and serum liver transaminases, while prominently increase that of endogenous antioxidant enzymes. Our study therefore presents a liver-targeting drug delivery strategy for the prevention and treatment of hepatic diseases.

Optimized methyl donor and reduced precursor degradation pathway for seleno-methylselenocysteine production in Bacillus subtilis

BACKGROUND

Seleno-methylselenocysteine (SeMCys) is an effective component of selenium supplementation with anti-carcinogenic potential that can ameliorate neuropathology and cognitive deficits. In a previous study, a SeMCys producing strain of Bacillus subtilis GBACB was generated by releasing feedback inhibition by overexpression of cysteine-insensitive serine O-acetyltransferase, enhancing the synthesis of S-adenosylmethionine as methyl donor by overexpression of S-adenosylmethionine synthetase, and expressing heterologous selenocysteine methyltransferase. In this study, we aimed to improve GBACB SeMCys production by synthesizing methylmethionine as a donor to methylate selenocysteine and by inhibiting the precursor degradation pathway.

RESULTS

First, the performance of three methionine S-methyltransferases that provide methylmethionine as a methyl donor for SeMCys production was determined. Integration of the NmMmt gene into GBACB improved SeMCys production from 20.7 to 687.4 μg/L. Next, the major routes for the degradation of selenocysteine, which is the precursor of SeMCys, were revealed by comparing selenocysteine hyper-accumulating and non-producing strains at the transcriptional level. The iscSB knockout strain doubled SeMCys production. Moreover, deleting sdaA, which is responsible for the degradation of serine as a precursor of selenocysteine, enhanced SeMCys production to 4120.3 μg/L. Finally, the culture conditions in the flasks were optimized. The strain was tolerant to higher selenite content in the liquid medium and the titer of SeMCys reached 7.5 mg/L.

CONCLUSIONS

The significance of methylmethionine as a methyl donor for SeMCys production in B. subtilis is reported, and enhanced precursor supply facilitates SeMCys synthesis. The results represent the highest SeMCys production to date and provide insight into Se metabolism.

Establishing extended pluripotent stem cells from human urine cells

BACKGROUND

Extended pluripotent stem cells (EPSCs) can contribute to both embryonic and trophectoderm-derived extraembryonic tissues. Therefore, EPSCs have great application significance for both research and industry. However, generating EPSCs from human somatic cells remains inefficient and cumbersome.

RESULTS

In this study, we established a novel and robust EPSCs culture medium OCM175 with defined and optimized ingredients. Our OCM175 medium contains optimized concentration of L-selenium-methylcysteine as a source of selenium and ROCK inhibitors to maintain the single cell passaging ability of pluripotent stem cells. We also used Matrigel or the combination of laminin 511 and laminin 521(1:1) to bypass the requirement of feeder cells. With OCM175 medium, we successfully converted integration-free iPSCs from easily available human Urine-Derived Cells (hUC-iPSCs) into EPSCs (O-IPSCs). We showed that our O-IPSCs have the ability to form both intra- and extra- embryonic chimerism, and could contribute to the trophoblast ectoderm lineage and three germ layer cell lineages.

CONCLUSIONS

In conclusion, our novel OCM175 culture medium has defined, optimized ingredients, which enables efficient generation of EPSCs in a feeder free manner. With the robust chimeric and differentiation potential, we believe that this system provides a solid basis to improve the application of EPSCs in regenerative medicine.

Selenium speciation-dependent cancer radiosensitization by induction of G2/M cell cycle arrest and apoptosis

Introduction: Radiation therapy has Q6long been a routine and effective treatment for non-small cell lung cancer (NSCLC), but the radioresistance and side effects have limited its application. In recent years, the superiority showed by trace element selenium in tumor radiotherapy sensitization has received wide attention. However, different forms of selenium compounds exhibit different chemical properties and their mechanisms of action on tumors may be different. Methods: Human non-small cell lung cancer SPC-A1 cells were studied. Drug toxicity was detected by MTT assay. The selenium content absorbed in vitro at different time points was detected by ICP-MS. Colony formation were conducted to observe the radiosensitization effect of different selenium compounds on SPC-A1 cells, and to compare the proliferation ability of SPC-A1 cells treated by radiation alone and radiation combined with different selenium compounds. Cell migration was detected by cell scratch assay. The changes of cell cycle and apoptosis were detected by flow cytometry. DCFH-DA fluorescent probe was used to detect the effects of different selenium compounds combined with X-ray on ROS production. Results: In this study, these four representative selenium compounds all have a certain ability to enhance the ability of radiotherapy to inhibit tumor cell proliferation and migration, and the mechanism may be related to blocking cell cycle in G2/M phase, activating the caspase cascade and reducing intracellular ROS levels to induce tumor cell apoptosis. Among them, -2-valent organic selenium has the most obvious effect, mainly inhibits cell migration, and induces early apoptosis by activating a large number of caspase-3, and arrest the cell cycle in S phase and G2/M phase. 0-valent selenium nanoparticles mainly arrest the cell cycle in G2/M phase. +4-valent inorganic selenium exerts its antitumor effects primarily by inhibiting tumor cell migration and inducing early apoptosis of tumor cells. Discussion: In this paper, the antitumor effects of four different forms of selenium compounds combined with X-rays on SPC-A1 cells were investigated, and their inhibitory effects on the proliferation and migration of cancer cells and their mechanisms were examined. We found that the radiosensitizing effect of selenium on NSCLC was closely related to its selenium form through the study of the sensitizing effect of different kinds of selenium compounds on radiotherapy.

Selenium-Containing Agents Acting on Cancer-A New Hope?

Selenium-containing agents are more and more considered as an innovative potential treatment option for cancer. Light is shed not only on the considerable advancements made in understanding the complex biology and chemistry related to selenium-containing small molecules but also on Se-nanoparticles. Numerous Se-containing agents have been widely investigated in recent years in cancer therapy in relation to tumour development and dissemination, drug delivery, multidrug resistance (MDR) and immune system-related (anti)cancer effects. Despite numerous efforts, Se-agents apart from selenocysteine and selenomethionine have not yet reached clinical trials for cancer therapy. The purpose of this review is to provide a concise critical overview of the current state of the art in the development of highly potent target-specific Se-containing agents.

Seleno-Metabolites and Their Precursors: A New Dawn for Several Illnesses?

Selenium (Se) is an essential element for human health as it is involved in different physiological functions. Moreover, a great number of Se compounds can be considered potential agents in the prevention and treatment of some diseases. It is widely recognized that Se activity is related to multiple factors, such as its chemical form, dose, and its metabolism. The understanding of its complex biochemistry is necessary as it has been demonstrated that the metabolites of the Se molecules used to be the ones that exert the biological activity. Therefore, the aim of this review is to summarize the recent information about its most remarkable metabolites of acknowledged biological effects: hydrogen selenide (HSe⁻/H₂Se) and methylselenol (CH₃SeH). In addition, special attention is paid to the main seleno-containing precursors of these derivatives and their role in different pathologies.

Homotypic targeting of immunomodulatory nanoparticles for enhanced peripheral and central immunity

OBJECTIVES

Synthetic oligodeoxynucleotides (ODNs) that contain unmethylated cytosine-phosphate-guanine (CpG) motifs serve as immune adjuvants in disease treatment. However, the poor cell permeability and safety concerns limit their medical applications, and biocompatible strategies for efficient delivery of functional CpG ODNs are highly desirable.

MATERIALS AND METHODS

Self-assembled, cell membrane-coated CpG nanoparticles (NP) are prepared, and their physicochemical properties are characterized. The uncoated and membrane-coated CpG NP are compared for their biocompatibility, cellular uptake kinetics, endocytic pathways, subcellular localization, and immunostimulatory activities in macrophages and microglia.

RESULTS

Macrophage- or microglia-derived cell membrane camouflaging alters the endocytic pathways of CpG NP, promotes their targeted delivery to the cells with homologous membrane, ensures their endosomal localization, and enhances their immunomodulatory effects.

CONCLUSIONS

We design a type of biomimetic NP consisting of self-assembled CpG NP core and cell membrane shell, and demonstrate its advantages in the modulation of peripheral and central immune cells. Our study provides a new strategy for the application of CpG ODNs.

L-Se-methylselenocysteine sensitizes lung carcinoma to chemotherapy

Objectives

Organic Selenium (Se) compounds such as L‐Se‐methylselenocysteine (L‐SeMC/SeMC) have been employed as a class of anti‐oxidant to protect normal tissues and organs from chemotherapy‐induced systemic toxicity. However, their comprehensive effects on cancer cell proliferation and tumour progression remain elusive.

Materials and Methods

CCK‐8 assays were conducted to determine the viabilities of cancer cells after exposure to SeMC, chemotherapeutics or combined treatment. Intracellular reactive oxygen species (ROS) levels and lipid peroxidation levels were assessed via fluorescence staining. The efficacy of free drugs or drug‐loaded hydrogel against tumour growth was evaluated in a xenograft mouse model.

Results

Among tested cancer cells and normal cells, the A549 lung adenocarcinoma cells showed higher sensitivity to SeMC exposure. In addition, combined treatments with several types of chemotherapeutics induced synergistic lethality. SeMC promoted lipid peroxidation in A549 cells and thereby increased ROS generation. Significantly, the in vivo efficacy of combination therapy was largely potentiated by hydrogel‐mediate drug delivery.

Conclusions

Our study reveals the selectivity of SeMC in the inhibition of cancer cell proliferation and develops an efficient strategy for local combination therapy.