The selenium analog of the chemopreventive compound S,S'-(1,4-phenylenebis[1,2-ethanediyl])bisisothiourea is a remarkable inducer of apoptosis and inhibitor of cell growth in human non-small cell lung cancer

The role of histone post-translational modifications in cancer and cancer immunity: functions, mechanisms and therapeutic implications

Histones play crucial roles in both promoting and repressing gene expression, primarily regulated through post-translational modifications (PTMs) at specific amino acid residues. Histone PTMs, including methylation, acetylation, ubiquitination, phosphorylation, lactylation, butyrylation, and propionylation, act as important epigenetic markers. These modifications influence not only chromatin compaction but also gene expression. Their importance extends to the treatment and prevention of various human diseases, particularly cancer, due to their involvement in key cellular processes. Abnormal histone modifications and the enzymes responsible for these alterations often serve as critical drivers in tumor cell proliferation, invasion, apoptosis, and stemness. This review introduces key histone PTMs and the enzymes responsible for these modifications, examining their impact on tumorigenesis and cancer progression. Furthermore, it explores therapeutic strategies targeting histone PTMs and offers recommendations for identifying new potential therapeutic targets.

Selective Impact of Selenium Compounds on Two Cytokine Storm Players

COVID-19 patients suffer from the detrimental effects of cytokine storm and not much success has been achieved to overcome this issue. We sought to test the ability of selenium to reduce the impact of two important cytokine storm players: IL-6 and TNF-α. The effects of four selenium compounds on the secretion of these cytokines from THP-1 macrophages were evaluated in vitro following an LPS challenge. Also, the potential impact of methylseleninic acid (MSeA) on Nrf2 and IκBα was determined after a short treatment of THP-1 macrophages. MSeA was found to be the most potent selenium form among the four selenium compounds tested that reduced the levels of IL-6 and TNF-α secreted by THP-1 macrophages. In addition, an increase in Nrf2 and decrease in pIκBα in human macrophages was observed following MSeA treatment. Our data indicate that COVID-19 patients might benefit from the addition of MSeA to the standard therapy due to its ability to suppress the key players in the cytokine storm.

Selenium Induces Pancreatic Cancer Cell Death Alone and in Combination with Gemcitabine

Survival rate for pancreatic cancer remains poor and newer treatments are urgently required. Selenium, an essential trace element, offers protection against several cancer types and has not been explored much against pancreatic cancer specifically in combination with known chemotherapeutic agents. The present study was designed to investigate selenium and Gemcitabine at varying doses alone and in combination in established pancreatic cancer cell lines growing in 2D as well as 3D platforms. Comparison of multi-dimensional synergy of combinations’ (MuSyc) model and highest single agent (HSA) model provided quantitative insights into how much better the combination performed than either compound tested alone in a 2D versus 3D growth of pancreatic cancer cell lines. The outcomes of the study further showed promise in combining selenium and Gemcitabine when evaluated for apoptosis, proliferation, and ENT1 protein expression, specifically in BxPC-3 pancreatic cancer cells in vitro.

Induction of intrinsic apoptotic signaling pathway in A549 lung cancer cells using silver nanoparticles from Gossypium hirsutum and evaluation of in vivo toxicity

In the past decade, the research communities raised wide concerns on using medicinal plants for synthesis of nanomaterials due to its effective biological activity, lower side effects and also eco-friendly manner. Our previous report concentrated on the biomedical efficacy of fine characterized silver nanoparticles (AgNPs) from Gossypium hirsutum (cotton) leaf extract. Further, the current examination is planned to reveal the molecular mechanisms involving for activation of mitochondria-mediated signaling pathway by AgNPs in human lung cancer cells (A549) using various biological endpoints such as apoptotic induction by HOECHST 33342, AO/EtBr and Rhodamine 123 staining, cell cycle analysis using flow cytometry, gene and protein expressions by RT-PCR and immunoblotting respectively. This study was further extended to identify the toxicity of AgNPs using an animal model. Interestingly, we observed that A549 cells treated with AgNPs resulted in G2/M arrest and ultimately leads to induction of apoptosis cell death. Moreover, gene analysis demonstrated that diminished expression of anti-apoptotic (Bcl-2) and enhanced expression of pro-apoptotic (Bax) mitochondrial genes. The alterations in the gene pattern may interrupt of mitochondrial membrane potential which facilitates the releasing of cytochrome c (cyt c) into cytosol. The cyt c act as a key molecule for activation of caspases (9 and 3) to initiate intrinsic apoptotic signaling cell death process. The histological analysis proven the application of AgNPs in nanomedicine is quietly harmless and would not cause any discernible stress like swelling and inflammation to the organs of mice. Taken together, this investigation may provide solid evidence for cotton crop mediated AgNPs induced apoptosis cell death pathway and offer a novel approach for cancer therapy.

Chalcogen containing heterocyclic scaffolds: New hybrids with antitumoral activity

In this work, 27 novel hybrid derivatives containing diverse substituents with chalcogen atoms (selenium or sulfur) and several active heterocyclic scaffolds have been synthesized. Compounds were tested against two human cancer cells lines (MCF7 and PC-3) and a normal human mammary epithelial cell line (184B5) in order to determine their activity and selectivity against malignant cells. Ten compounds showed GI50 values below 10 μM in at least one of the cancer cell lines and six of them exhibited a selectivity index higher than 9. In general, selenium-containing compounds were more active than their corresponding sulfur analogs but we found some thiocyanate derivatives with comparable or higher activity and selectivity. Among the different substituents, the seleno- and thio-cyanate groups showed the most promising results. On the basis of their potent activity and high selectivity index, compounds 7e and 8f (containing a thiocyanate and a selenocyanate group, respectively) were selected for further biological evaluation. Both the compounds induced caspase-dependent cell death and cell cycle arrest in G2/M phase. In addition, these compounds do not violate any of the Lipinski's Rule of Five and thus possess good potential to become drugs, compound 7e being particularly promising.

A Selenium Containing Inhibitor for the Treatment of Hepatocellular Cancer

Hepatocellular carcinoma (HCC) is the third most deadly cancer in the world. New treatment strategies are desperately needed due to limited standard therapies. Activation of the Erk, Akt, and STAT3pathways is implicated in the prognosis of HCC. The Se,Se'-1,4-phenylenebis(1,2-ethanediyl) bisisoselenourea (PBISe), is a selenium-containing MAPK and PI3 kinase inhibitor, effectively inhibit tumorigenesis in a variety of experimental models. The aim of our study is to demonstrate the potential role of PBISe in the treatment of HCC. The anti-proliferative and pro-apoptotic ability of PBISe is studied in vitro in four human HCC cell lines and in vivo in a spontaneous murine HCC model. Inhibition of cancer growth was performed by cell viability assay and apoptosis by caspase 3/7, PARP cleavage, annexin-V, and TUNEL assays. Role of PBISe on PI3 kinase, MAPK and STAT3 signaling is determined by Western blotting. In vivo effects of PBISe on tumor sizes were monitored using MRI in a spontaneous murine HCC. Liver tissues from the PBISe-treated mice are analyzed for angiogenesis, proliferation, and signaling pathway markers. Overall, PBISe activated caspase-3/7 and increased DNA fragmentation, which is positively correlated with the increased PARP cleavage. PBISe promoted apoptosis by inhibiting PI3K, MAPK, and STAT3 signaling with significant reduction in the tumor sizes (p < 0.007). PBISe-treated tumors reduced survival marker PCNA, and angiogenesis markers Vegf-A, Vegf-R3 and CD34. These results demonstrate the chemotherapeutic effects of PBISe, by inhibiting tumor growth and facilitating tumor apoptosis for HCC treatment.

Novel seleno- and thio-urea derivatives with potent in vitro activities against several cancer cell lines

A series of novel selenourea derivatives and corresponding thiourea analogs were synthesized and tested against a panel of six human cancer cell lines: melanoma (1205Lu), lung carcinoma (A549), prostatic carcinoma (DU145), colorectal carcinoma (HCT116), pancreatic epithelioid carcinoma (PANC-1) and pancreatic adenocarcinoma (BxPC3). In general, we found that the selenium-containing derivatives were more potent than their isosteric sulfur analogs. Four selenourea derivatives (1e, 1f, 1g and 1i) showed IC50 values below 10 μM in all of tested cell lines at 72 h. On the basis of its potent activity, compound 1g was selected for further biological evaluation in different colon cancer cell lines. Our results indicated that compound 1g induced apoptosis by caspase activation, along with inhibition of anti-apoptotic proteins.

PVM/MA-shelled selol nanocapsules promote cell cycle arrest in A549 lung adenocarcinoma cells

BACKGROUND

Selol is an oily mixture of selenitetriacylglycerides that was obtained as a semi-synthetic compound containing selenite. Selol is effective against cancerous cells and less toxic to normal cells compared with inorganic forms of selenite. However, Selol's hydrophobicity hinders its administration in vivo. Therefore, the present study aimed to produce a formulation of Selol nanocapsules (SPN) and to test its effectiveness against pulmonary adenocarcinoma cells (A549).

RESULTS

Nanocapsules were produced through an interfacial nanoprecipitation method. The polymer shell was composed of poly(methyl vinyl ether-co-maleic anhydride) (PVM/MA) copolymer. The obtained nanocapsules were monodisperse and stable. Both free Selol (S) and SPN reduced the viability of A549 cells, whereas S induced a greater reduction in non-tumor cell viability than SPN. The suppressor effect of SPN was primarily associated to the G2/M arrest of the cell cycle, as was corroborated by the down-regulations of the CCNB1 and CDC25C genes. Apoptosis and necrosis were induced by Selol in a discrete percentage of A549 cells. SPN also increased the production of reactive oxygen species, leading to oxidative cellular damage and to the overexpression of the GPX1, CYP1A1, BAX and BCL2 genes.

CONCLUSIONS

This study presents a stable formulation of PVM/MA-shelled Selol nanocapsules and provides the first demonstration that Selol promotes G2/M arrest in cancerous cells.

Combination of fenretinide and selenite inhibits proliferation and induces apoptosis in ovarian cancer cells

The combination of fenretinide and selenite on ovarian cancer cells was investigated to assess its effects on proliferation and ability to induce apoptosis. Our results showed that fenretinide and selenite in combination significantly suppress the proliferation of ovarian cancer cells and induced apoptosis (including reactive oxygen species generation, and the loss of mitochondrial membrane potential) compared with either drug used alone. The caspase3/9-dependent pathway was triggered significantly in combination treatment, and moreover, the AMPK pathway also mediated the apoptosis induction in fenretinide and selenite combination. Fenretinide and selenite combination treatment was demonstrated to suppress tumor growth in vivo, this drug combination has been thus found to have an enhanced anti-tumor effect on ovarian cancers cells.

Asperolide A, a marine-derived tetranorditerpenoid, induces G2/M arrest in human NCI-H460 lung carcinoma cells, is mediated by p53-p21 stabilization and modulated by Ras/Raf/MEK/ERK signaling pathway

Here we first demonstrate that asperolide A, a very recently reported marine-derived tetranorditerpenoid, leads to the inhibition of NCI-H460 lung carcinoma cell proliferation by G2/M arrest with the activation of the Ras/Raf/MEK/ERK signaling and p53-dependent p21 pathway. Treatment with 35 μM asperolide A (2 × IC₅₀) resulted in a significant increase in the proportion of G2/M phase cells, about a 2.9-fold increase during 48 h. Immunoblot assays demonstrated time-dependent inhibition of G2/M regulatory proteins. Moreover, asperolide A significantly activated MAP kinases (ERK1/2, JNK and p38 MAP kinase) by phosphorylation, and only the inhibition of ERK activation by PD98059 reversed downregulation of G2/M regulatory proteins CDC2, and suppressed upregulation of p21 and p-p53 levels. Transfection of cells with dominant-negative Ras (RasN17) mutant genes up-regulated asperolide A-induced the decrease of cyclin B1 and CDC2, suppressed Raf, ERK activity and p53-p21 expression, and at last, abolished G2/M arrest. This study indicates that asperolide A-induced G2/M arrest in human NCI-H460 lung carcinoma cells relys on the participation of the Ras/Raf/MEK/ERK signaling pathway in p53-p21 stabilization. An in vivo study with asperolide A illustrated a marked inhibition of tumor growth, and little toxcity compared to Cisplatin therapy. Overall, these findings provide potential effectiveness and a theoretical basis for the therapeutic use of asperolide A in the treatment of malignancies.

Simultaneous targeting of COX-2 and AKT using selenocoxib-1-GSH to inhibit melanoma

Melanoma is a highly metastatic and deadly disease. An agent simultaneously targeting the COX-2, PI3K/Akt, and mitogen-activated protein kinase (MAPK) signaling pathways that are deregulated in up to 70% of sporadic melanomas might be an effective treatment, but no agent of this type exists. To develop a single drug inhibiting COX-2 and PI3K/Akt signaling (and increasing MAPK pathway activity to inhibitory levels as a result of Akt inhibition), a selenium-containing glutathione (GSH) analogue of celecoxib, called selenocoxib-1-GSH was synthesized. It killed melanoma cells with an average IC(50) of 7.66 μmol/L compared with control celecoxib at 55.6 μmol/L. The IC(50) range for normal cells was 36.3 to 41.2 μmol/L compared with 7.66 μmol/L for cancer cells. Selenocoxib-1-GSH reduced development of xenografted tumor by approximately 70% with negligible toxicity by targeting COX-2, like celecoxib, and having novel inhibitory properties by acting as a PI3K/Akt inhibitor (and MAPK pathway activator to inhibitory levels due to Akt inhibition). The consequence of this inhibitory activity was an approximately 80% decrease in cultured cell proliferation and an approximately 200% increase in apoptosis following 24-hour treatment with 15.5 μmol/L of drug. Thus, this study details the development of selenocoxib-1-GSH, which is a nontoxic agent that targets the COX-2 and PI3K/Akt signaling pathways in melanomas to inhibit tumor development.

Selenium compounds, apoptosis and other types of cell death: an overview for cancer therapy

Selenium (Se) is an essential trace element involved in different physiological functions of the human body and plays a role in cancer prevention and treatment. Induction of apoptosis is considered an important cellular event that can account for the cancer preventive effects of Se. The mechanisms of Se-induced apoptosis are associated with the chemical forms of Se and their metabolism as well as the type of cancer studied. So, some selenocompounds, such as SeO₂ involve the activation of caspase-3 while sodium selenite induces apoptosis in the absence of the activation of caspases. Modulation of mitochondrial functions has been reported to play a key role in the regulation of apoptosis and also to be one of the targets of Se compounds. Other mechanisms for apoptosis induction are the modulation of glutathione and reactive oxygen species levels, which may function as intracellular messengers to regulate signaling pathways, or the regulation of kinase, among others. Emerging evidence indicates the overlaps between the apoptosis and other types of cell death such as autophagy. In this review we report different processes of cell death induced by Se compounds in cancer treatment and prevention.

Selenoprotein W depletion induces a p53- and p21-dependent delay in cell cycle progression in RWPE-1 prostate epithelial cells

The anticancer activity of selenium (Se) has been demonstrated in myriad animal and in vitro studies, yet the mechanisms remain obscure. The main form of Se in animal tissues is selenocysteine in selenoproteins, but the relative importance of selenoproteins versus smaller Se compounds in cancer protection is unresolved. Selenoprotein W (SEPW1) is a highly conserved protein ubiquitously expressed in animals, bacteria, and archaea. SEPW1 depletion causes a delay in cell cycle progression at the G1/S transition of the cell cycle in breast and prostate epithelial cells. Tumor suppressor protein p53 is a master regulator of cell cycle progression and is the most frequently mutated gene in human cancers. p53 was increased in SEPW1 silenced cells and was inversely correlated with SEPW1 mRNA in cell lines with altered SEPW1 expression. Silencing SEPW1 decreased ubiquitination of p53 and increased p53 half-life. SEPW1 silencing increased p21(Cip1/WAF1/CDKN1A), while p27 (Kip1/CDKN1B) levels were unaffected. G1-phase arrest from SEPW1 knockdown was abolished by silencing p53 or p21. Cell cycle arrest from SEPW1 silencing was not associated with activation of ATM or phosphorylation of Ser-15 in p53, suggesting the DNA damage response pathway was not involved. Silencing GPX1 had no effect on cell cycle, suggesting that G1-phase arrest from SEPW1 silencing was not due to loss of antioxidant protection. More research is required to identify the function of SEPW1 and how it affects stability of p53.