Sodium selenite increases the activity of the tumor suppressor protein, PTEN, in DU-145 prostate cancer cells

Selenochemical modification of low molecular weight polysaccharides from Grifola frondosa and the mechanism of their inhibitory effects on gastric cancer cells

An important micronutrient involved in immune response and antitumor is selenium. LMW-GFP, a polysaccharide extracted from Grifola frondosa seed bodies, has a relatively weak antitumor effect on BGC-823 and MFC cells in vitro, whereas selenium binding to LMW-GFP can significantly increase the in vitro antitumor activity of LMW-GFP. In this study, Se-LMW-GFP was prepared by the HNO3-Na2SeO3 method, and the structures of LMW-GFP and Se-LMW-GFP were characterized by UV-visible spectroscopy of absorption, FTIR spectroscopy, and electron scanning microscopy, and these structural analyses showed that selenium was successfully complexed to LMW-GFP. The selenium content of Se-LMW-GFP was measured to be 2.08 % ± 0.08 % by ICP-MS. The anti-tumor activity of LMW-GFP before and after selenium modification was compared by cellular experiments, and the findings indicated that the anti-tumor activity of Se-LMW-GFP was considerably improved over that of LMW-GFP, and inhibited the proliferation of BGC-823 cells and MFC cells through a combination of the Fas/FasL-mediated exogenous death receptor pathway as well as the endogenous mitochondrial pathway. Our results suggest that Se-LMW-GFP not only has great potential for natural health food and anti-gastric cancer drug development but is also a good selenium supplement.

Thioredoxin-1 inhibits the activation of IRE1 by targeting Hsp90/p-Cdc37 chaperone complex in Parkinson disease

Endoplasmic reticulum stress is implicated in the etiopathogenesis of Parkinson disease (PD). Our previous study has revealed that thioredoxin-1 (Trx-1) attenuated IRE1 activation in 1-methyl-4-phenylpyridinium ion (MPP+)/1-methy-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD models. However, its exact mechanism has been largely unclear. In this research, it was reported for the first time that the protein levels of heat shock protein 90 (Hsp90) and phosphorylated cell division cycle 37 (p-Cdc37) were significantly decreased and the interaction of Hsp90/p-Cdc37 complex with IRE1 was disturbed in MPP+/MPTP-induced PD models. Trx-1 overexpression reversed the expression of Hsp90 and p-Cdc37 in cultured cells and the substantia nigra pars compacta of mice. More importantly, Trx-1 overexpression enhanced the interaction of Hsp90/p-Cdc37 complex with IRE1. In conclusion, our data demonstrated that Trx-1 inhibited IRE1 activation in PD by elevating the expression of Hsp90 and p-Cdc37 and strengthening the interaction of Hsp90/p-Cdc37 complex and IRE1.

A Study on Myogenesis by Regulation of Reactive Oxygen Species and Cytotoxic Activity by Selenium Nanoparticles

Reactive oxygen species (ROS) are continuously produced by skeletal muscle during contractile activity and even at rest. However, the ROS generated from excessive exercise or traumatic damage may produce more ROS than can be neutralized by an antioxidant capacity, which can be harmful to muscle function. In particular, selenium is a known antioxidant that regulates physiological functions such as cell differentiation and anti-inflammatory function. In this study, we developed nano-sized antioxidative biomaterials using selenium to investigate the protective and differentiation effects against C2C12 myoblasts in an H₂O₂-induced oxidative stress environment. The selenium nanoparticles (SeNPs) were produced with a size of 35.6 ± 4.3 nm and showed antioxidant effects according to the 3,3′,5,5′-tetramethylbenzidine assay. Then, SeNPs were treated to C2C12 cells with or without H₂O₂. Our results showed that SeNPs reduced C2C12 apoptosis and intracellular ROS levels. Additionally, SeNPs effectively up-regulated in the presence of H₂O₂, MyoD, MyoG, α-actinin, and myosin heavy chain, which are well known to increase during myoblast differentiation as assayed by qRT-PCR, immunocytochemistry-staining, western blotting. These results demonstrate that SeNPs can accelerate differentiation with its protective effects from the ROS environment and can be applied to the treatment of skeletal muscle in a cellular redox environment.

Selenium-rich royal jelly inhibits hepatocellular carcinoma through PI3K/AKT and VEGF pathways in H22 tumor-bearing mice

Royal jelly (RJ) and selenium (Se)-rich foods have well-known health benefits that are attributable to a broad range of pharmacological effects including antioxidant, anti-tumor, and immunoregulatory activities. However, the physiological effects of Se-rich RJ, which is produced by feeding Apis mellifera (Hymenoptera: Apidae) sodium selenite sucrose solution, are not well understood. The anti-hepatoma activity and mechanism of Se-rich RJ in H22 tumor-bearing mice were investigated in the current study. The findings showed that the content of organic and inorganic Se in Se-rich RJ was significantly higher than that in RJ. Furthermore, interleukin-2 (IL-2) levels and tumor necrosis factor-α (TNF-α) production in serum were increased and the malondialdehyde (MDA) content in liver was decreased in mice fed RJ and Se-rich RJ. 16SrRNA sequencing and serum untargeted metabolomics showed that RJ and Se-rich RJ could modulate the gut microbiota, and fisetin and l-glutathione oxidized were the main anti-tumor components in RJ and Se-rich RJ. Further analysis showed 11-deoxy prostaglandin F1β was the specific anti-tumor metabolite in mice treated with Se-rich RJ compared with RJ. The results indicated that RJ and Se-rich RJ could inhibit the expression of PI3K and phosphorylation of AKT, induce cell apoptosis through the activation of caspase-9 and caspase-3, and regulate Bcl-2/Bax expression. RJ and Se-rich RJ also inhibited the expression of COX-2 and VEGF. To summarize, the findings clearly demonstrate that Se-rich RJ could inhibit tumor growth by inducing apoptosis and inhibiting angiogenesis as well as exhibit anti-tumor effects by improving immune function and antioxidant activities. The results indicated that Se-rich RJ could be a potential functional food for the management and prevention of cancer.

The Effect of Selenium Nanoparticles on the Osteogenic Differentiation of MC3T3-E1 Cells

Reactive oxygen species (ROS) regulate various functions of cells, including cell death, viability, and differentiation, and nanoparticles influence ROS depending on their size and shape. Selenium is known to regulate various physiological functions, such as cell differentiations and anti-inflammatory functions, and plays an important role in the regulation of ROS as an antioxidant. This study aims to investigate the effect of selenium nanoparticles (SeNPs) on the differentiation of osteogenic MC3T3-E1 cells. After fabrication of SeNPs with a size of 25.3 ± 2.6 nm, and confirmation of its oxidase-like activity, SeNPs were added to MC3T3-E1 cells with or without H₂O₂: 5~20 μg/mL SeNPs recovered cells damaged by 200 μM H₂O₂ via the intracellular ROS downregulating role of SeNPs, revealed by the ROS staining assay. The increase in osteogenic maturation with SeNPs was gradually investigated by expression of osteogenic genes at 3 and 7 days, Alkaline phosphatase activity staining at 14 days, and Alizarin red S staining at 28 days. Therefore, the role of SeNPs in regulating ROS and their therapeutic effects on the differentiation of MC3T3-E1 cells were determined, leading to possible applications for bone treatment.

Revisiting prostate cancer metabolism: From metabolites to disease and therapy

Prostate cancer (PCa), one of the most commonly diagnosed cancers worldwide, still presents important unmet clinical needs concerning treatment. In the last years, the metabolic reprogramming and the specificities of tumor cells emerged as an exciting field for cancer therapy. The unique features of PCa cells metabolism, and the activation of specific metabolic pathways, propelled the use of metabolic inhibitors for treatment. The present work revises the knowledge of PCa metabolism and the metabolic alterations that underlie the development and progression of the disease. A focus is given to the role of bioenergetic sources, namely, glucose, lipids, and glutamine sustaining PCa cell survival and growth. Moreover, it is described as the action of oncogenes/tumor suppressors and sex steroid hormones in the metabolic reprogramming of PCa. Finally, the status of PCa treatment based on the inhibition of metabolic pathways is presented. Globally, this review updates the landscape of PCa metabolism, highlighting the critical metabolic alterations that could have a clinical and therapeutic interest.

Treatment Stratification of Patients with Metastatic Castration-Resistant Prostate Cancer by Machine Learning

Prostate cancer is the most common cancer in men in the Western world. One-third of the patients with prostate cancer will develop resistance to hormonal therapy and progress into metastatic castration-resistant prostate cancer (mCRPC). Currently, docetaxel is a preferred treatment for mCRPC. However, about 20% of the patients will undergo early therapeutic failure owing to adverse events induced by docetaxel-based chemotherapy. There is an emergent need for a computational model that can accurately stratify patients into docetaxel-tolerable and docetaxel-intolerable groups. Here we present the best-performing algorithm in the Prostate Cancer DREAM Challenge for predicting adverse events caused by docetaxel treatment. We integrated the survival status and severity of adverse events into our model, which is an innovative way to complement and stratify the treatment discontinuation information. Critical stratification biomarkers were further identified in determining the treatment discontinuation. Our model has the potential to improve future personalized treatment in mCRPC.

Emerging Anticancer Potentials of Selenium on Osteosarcoma

Selenium is a trace element essential to humans and forms complexes with proteins, which exert physiological functions in the body. In vitro studies suggested that selenium possesses anticancer effects and may be effective against osteosarcoma. This review aims to summarise current evidence on the anticancer activity of inorganic and organic selenium on osteosarcoma. Cellular studies revealed that inorganic and organic selenium shows cytotoxicity, anti-proliferative and pro-apoptotic effects on various osteosarcoma cell lines. These actions may be mediated by oxidative stress induced by selenium compounds, leading to the activation of p53, proapoptotic proteins and caspases. Inorganic selenium is selective towards cancer cells, but can cause non-selective cell death at a high dose. This condition challenges the controlled release of selenium from biomaterials. Selenium treatment in animals inoculated with osteosarcoma reduced the tumour size, but did not eliminate the incidence of osteosarcoma. Only one study investigated the relationship between selenium and osteosarcoma in humans, but the results were inconclusive. In summary, although selenium may exert anticancer properties on osteosarcoma in experimental model systems, its effects in humans require further investigation.

Organoids Increase the Predictive Value of in vitro Cancer Chemoprevention Studies for in vivo Outcome

Epidemiological and preclinical data suggest that antioxidants are protective against prostate cancer whose pathogenesis has been linked to oxidative stress. However, the selenium and vitamin E Cancer Prevention Trial (SELECT), found no efficacy for selenium in reducing prostate cancer incidence while vitamin E was associated with an increased risk of the disease. These results have called in to question the models used in preclinical chemoprevention efficacy studies and their ability to predict in vivo outcomes. Chemoprevention agents have traditionally been tested on two dimensional monolayer cultures of cell lines derived from advanced prostate cancers. But as SELECT demonstrates, results from advanced disease models were not predictive of the outcome of a primary chemoprevention trial. Additionally, lack of cell-matrix interactions in two dimensional cultures results in loss of biochemical and mechanical cues relevant for native tissue architecture. We use recent findings in three dimensional organoid cultures that recapitulated the SELECT trial results to argue that the organoid model could increase the predictive value of in vitro studies for in vivo outcomes.

Sodium selenite attenuates lung adenocarcinoma progression by repressing SOX2-mediated stemness

PURPOSE

Sodium selenite (SS) has been widely reported to induce apoptosis in various cancer cell types. However, the underlying molecular mechanisms governing SS-mediated repression of lung cancer stem cells remain largely undefined.

METHODS

In vitro assays of cell proliferation, clonal formation, apoptosis, migration and cancer stemness cell sphere formation were performed to examine the inhibitory effects of SS on lung adenocarcinoma (LAD) cells with or without the overexpression of SRY-related high-mobility-group box 2 (SOX2).

RESULTS

SS significantly inhibited cell growth and induced apoptosis in LAD cells in a dose-dependent manner with marginal effects on normal epithelial cell HBEC. SS dramatically repressed expression of SOX2 and its upstream regulator GLI1 and strongly decreased stemness sphere formation in LAD cells at 10 µM. Forced expression of SOX2 significantly buffered anti-cancer effects of SS.

CONCLUSIONS

Our results demonstrate that SS attenuates lung adenocarcinoma progression by repressing SOX2 and its upstream regulator GLI1, which suggests that SS may be a potential therapeutic drug candidate for lung cancer patients.

Phosphatases and solid tumors: focus on glioblastoma initiation, progression and recurrences

Phosphatases and cancer have been related for many years now, as these enzymes regulate key cellular functions, including cell survival, migration, differentiation and proliferation. Dysfunctions or mutations affecting these enzymes have been demonstrated to be key factors for oncogenesis. The aim of this review is to shed light on the role of four different phosphatases (PTEN, PP2A, CDC25 and DUSP1) in five different solid tumors (breast cancer, lung cancer, pancreatic cancer, prostate cancer and ovarian cancer), in order to better understand the most frequent and aggressive primary cancer of the central nervous system, glioblastoma.

In Vitro Antibacterial Spectrum of Sodium Selenite against Selected Human Pathogenic Bacterial Strains

The objective of this investigation was to predict the antibacterial properties of sodium selenite against selected human pathogens. A group of six human bacterial pathogens including Staphylococcus aureus, Streptococcus pyogenes, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella planticola were utilized for screening. The spectrum of activity was qualified based on zone of inhibition. Our study demonstrated that sodium selenite exhibits a strong spectrum of activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Klebsiella planticola. The spectrum of activity was compared with standard ciprofloxacin disc (5 μg/disc) and observed to have satisfactory effect.

Influence of concurrent medications on outcomes of men with prostate cancer included in the TAX 327 study

OBJECTIVES

The TAX 327 trial was pivotal in establishing docetaxel in castration refractory metastatic prostate cancer. Various commonly prescribed and over-the-counter co-administered medications are thought to exhibit anti-neoplastic properties and/or could potentially have pharmacokinectic interactions with docetaxel lessening the effectiveness of chemotherapy.

METHODS

To examine the effect of on prostate cancer outcomes within this trial, we examined overall survival, prostate-specific antigen (PSA) response, percent PSA reduction, pain response and QOL responses for 14 families of medications including metformin, digoxin, verapamil, proton pump inhibitors, nitrates, statins, cox-2 inhibitors, warfarin, heparins, ascorbic acid, selenium, tocopherol, antidepressants and erythropoietin.

RESULTS

Our findings did not reveal any medication that had a significant additive or synergistic effect with docetaxel. We did note, however, that patients on digoxin or verapamil had poorer overall survival, possibly due to a trend of fewer cycles of administered chemotherapy being administered to the verapamil group, consistent with a pharmacokinectic interaction.

CONCLUSIONS

These data are only hypothesis-generating given the statistical limitations, but may form a basis for similar future analysis in other malignancies. The data suggest the need to be aware of pharmacokinectic interactions with medications that may interact with docetaxel.

PTEN-regulated AKT/FoxO3a/Bim signaling contributes to reactive oxygen species-mediated apoptosis in selenite-treated colorectal cancer cells

Mounting evidence shows that selenium possesses chemotherapeutic potential against tumor cells, including leukemia, prostate cancer and colorectal cancer (CRC) cells. However, the detailed mechanism by which sodium selenite specifically kills tumor cells remains unclear. Herein, we demonstrated that supranutritional doses of selenite-induced apoptosis in CRC cells through reactive oxygen species (ROS)-dependent modulation of the PI3K/AKT/FoxO3a signaling pathway. First, we found that selenite treatment in HCT116 and SW480 CRC cells caused inhibition of AKT and the nuclear accumulation of FoxO3a by western blot and immunofluorescence analyses, respectively, thereby facilitating transcription of the target genes bim and PTEN. Modulation of the AKT/FoxO3a/Bim signaling pathway by chemical inhibitors or RNA interference revealed that these events were critical for selenite-induced apoptosis in CRC cells. Additionally, we discovered that FoxO3a-mediated upregulation of PTEN exerted a further inhibitory effect on the AKT survival pathway. We also corroborated our findings in vivo by performing immunohistochemistry experiments. In summary, our results show that selenite could induce ROS-dependent FoxO3a-mediated apoptosis in CRC cells and xenograft tumors through PTEN-mediated inhibition of the PI3K/AKT survival axis. These results help to elucidate the molecular mechanisms underlying selenite-induced cell death in tumor cells and provide a theoretical basis for translational applications of selenium.

PTEN modulators: a patent review

INTRODUCTION

PTEN (phosphatase and tensin homolog deleted on chromosome 10) plays a pivotal role in controlling intracellular signaling for cell survival and proliferation by inhibiting the PI3K/Akt pathway, and its dysfunction is associated with several neoplastic diseases. PTEN is frequently found mutated in many pathological conditions highlighting its importance in normal physiological function. Unlike several cellular proteins which are activated by phosphorylation, PTEN is inactivated upon phosphorylation by specific kinases which phosphorylate serine and threonine residues in its C-terminal region. Therefore, development of therapeutic agents that specifically target kinases and kinase-domain-containing proteins affecting PTEN would lead to the treatment of PTEN-related diseases.

AREAS COVERED

With increasing evidence on the role of PTEN in many human diseases, the present review focuses on the clinical relevance of PTEN with a comprehensive list of currently identified modulators of PTEN, and proposes potentially novel molecular targets which could aid in the development of drug candidates for the treatment of PTEN-related diseases such as cardiovascular diseases, diabetes, obesity, cancer, autism, Parkinson's and Alzheimer's diseases.

EXPERT OPINION

This review describes several target sites that could help in the development of novel drug candidates to regulate or restore the normal physiological functions of PTEN and are essential in the treatment of human diseases where PTEN plays a pivotal role.

Activation of Ras/PI3K/ERK pathway induces c-Myc stabilization to upregulate argininosuccinate synthetase, leading to arginine deiminase resistance in melanoma cells

Melanomas and other cancers that do not express argininosuccinate synthetase (AS), the rate-limiting enzyme for arginine biosynthesis, are sensitive to arginine depletion with pegylated arginine deiminase (ADI-PEG20). However, ADI resistance eventually develops in tumors because of AS upregulation. Although it has been shown that AS upregulation involves c-Myc, the underlying mechanisms remain unknown. Here we show that ADI-PEG20 activates Ras signaling and the effector extracellular signal-regulated kinase (ERK) and phosphoinositide 3-kinase (PI3K)/AKT/GSK-3β kinase cascades, resulting in phosphorylation and stabilization of c-Myc by attenuation of its ubiquitin-mediated protein degradation mechanism. Inhibition of the induced cell signaling pathways using PI3K/AKT inhibitors suppressed c-Myc induction and enhanced ADI-mediated cell killing. Notably, in an animal model of AS-negative melanoma, combination therapy using a PI3K inhibitor plus ADI-PEG20 yielded additive antitumor effects as compared with either agent alone. Taken together, our findings offer mechanistic insight into arginine deprivation metabolism and ADI resistance, and they illustrate how combining inhibitors of the Ras/ERK and PI3K/AKT signaling pathways may improve ADI-PEG20 anticancer responses.

Sodium selenite-induced apoptosis mediated by ROS attack in human osteosarcoma U2OS cells

Sodium selenite (Na(2)SeO(3), SSE) is an inorganic Se compound that is widely used in cancer chemoprevention studies. SSE has been shown to have anti-proliferative effects on several types of human cancer cells, but its effect on osteosarcoma cells has thus far not been reported. In this study, the cytotoxic effect of SSE on osteosarcoma cells U2OS was investigated in vitro and found to be higher than on comparable non-cancer cell lines 293 and L6. Treatment with SSE decreased cell growth in a dose- and time-dependent manner and altered cellular morphology. SSE also inhibited cell viability by inducing apoptosis, as evidenced by the formation of apoptotic bodies, generation of reactive oxygen species (ROS), and accumulation of cells during the advanced phase of apoptosis. SSE-induced apoptosis correlated with the activation of CASP 3, downregulation of BCL-2, and upregulation of P53 and PTEN in U2OS cells. These results indicated that SSE induces apoptosis in U2OS cells mainly through an ROS-mediated caspase pathway. This is the first report to show a possible mechanism of the anti-proliferative effect of SSE for the prevention of osteosarcoma in cell culture models.

Novel library of selenocompounds as kinase modulators

Although the causes of cancer lie in mutations or epigenic changes at the genetic level, their molecular manifestation is the dysfunction of biochemical pathways at the protein level. The 518 protein kinases encoded by the human genome play a central role in various diseases, a fact that has encouraged extensive investigations on their biological function and three dimensional structures. Selenium (Se) is an important nutritional trace element involved in different physiological functions with antioxidative, antitumoral and chemopreventive properties. The mechanisms of action for selenocompounds as anticancer agents are not fully understood, but kinase modulation seems to be a possible pathway. Various organosulfur compounds have shown antitumoral and kinase inhibition effects but, in many cases, the replacement of sulfur by selenium improves the antitumoral effect of compounds. Although Se atom possesses a larger atomic volume and nucleophilic character than sulfur, Se can also formed interactions with aminoacids of the catalytic centers of proteins. So, we propose a novel chemical library that includes organoselenium compounds as kinase modulators. In this study thirteen selenocompounds have been evaluated at a concentration of 3 or 10 µM in a 24 kinase panel using a Caliper LabChip 3000 Drug Discover Platform. Several receptor (EGFR, IGFR1, FGFR1…) and non-receptor (Abl) kinases have been selected, as well as serine/threonine/lipid kinases (AurA, Akt, CDKs, MAPKs…) implicated in main cancer pathways: cell cycle regulation, signal transduction, angiogenesis regulation among them. The obtained results showed that two compounds presented inhibition values higher than 50% in at least four kinases and seven derivatives selectively inhibited one or two kinases. Furthermore, three compounds selectively activated IGF-1R kinase with values ranging from −98% to −211%. In conclusion, we propose that the replacement of sulfur by selenium seems to be a potential and useful strategy in the search of novel chemical compound libraries against cancer as kinase modulators.