Evaluation of chemotherapeutic and cancer-protective properties of sphingosine and C2-ceramide in a human breast stem cell derived carcinogenesis model

Tolypothrix Dichloromethane Ethylacetate fraction (TDEF) inhibits cisplatin resistance H357 cell through PI3K/AKT/beta-catenin pathway

Chemoresistance is one of the major factors for treatment failure in OSCC. Reprogramming chemoresistance cells to undergo drug induced apoptotic cell death is a feasible approach to overcome drug resistance. Cyanobacteria is considered important sources of lead compounds for the development of drugs for treating cancer chemoresistance. This study deals with the role of Tolypothrix Dichloromethane Ethyl acetate fraction (TDEF) inducing apoptosis in cisplatin resistance H357 cell (H357cisR) and the underlying mechanisms sensitizing the chemoresistance. TDEF showing effective activity against H357cisR with IC50-14.13±1.18 µg mL-1, inhibits proliferation and migration. Proteome apoptosis arrays were found to stimulate phosphorylation of p53, activation of proapoptotic proteins including BAX and cytochrome C (CYCS), caspase-3/9 (CASP3/9), suppression of anti-apoptotic proteins like Bcl2, survivin and increased expression of the cell cycle checkpoint protein p21, p27. TDEF induced apoptosis with cell death-transducing signals, that regulate the Matrix metalloproteinases (MMPs) by down-regulation of Bcl2 and up-regulation of Bax, triggering the cytochrome c release from mitochondria to cytosol thus triggered the activation of caspases-9 to activate downstream executioner caspase-3/7 required for apoptotic changes. The mechanistic pathway of apoptotic cell death in H357cisR was done through inhibiting β-catenin through GSK3β in turn activated by AKT. The phosphorylated β-catenin leads to proteasome degradation and unable to translocation to nucleus thereby activating c-Myc, survivin, Cyclin D and upregulate p21 expression which lead to cell cycle arrest in G0/G1 phase.

UHPLC-MS/MS Studies and Antiproliferative Effects in Breast Cancer Cells of Mexican Sargassum

BACKGROUND

Sargassum is a marine organism that, under specific conditions, drastically increases its population damaging the environment and risking other organisms. However, sargassum could represent a source of bioactive compounds to treat different diseases such as cancer. Thus, aqueous, ethanolic, and ethyl acetate extracts of sargassum from Playa del Carmen, Mexico, were subjected to metabolomic and antiproliferative assays in breast cancer cells.

OBJECTIVE

To evaluate the biological effect of different extracts of sargassum, its toxicity over Artemia salina and its antiproliferative effect tested in MCF-7, MDA-MB-231, and NIH3T3 cell lines. Finally, using UHPLC-MS/MS to identify the metabolites in each extract to correlate them with its antiproliferative effect.

METHODS

The sargassum sample collection was carried out in September at three different points in Playa del Carmen, Quintana Roo, Mexico. The aqueous, ethanolic, and ethyl acetate extracts of Mexican sargassum were obtained by evaporation of solvent and lyophilization. Then, these extracts were evaluated in the cytotoxicity bioassay of Artemia salina. Next, its antiproliferative effect was assessed in MCF-7, MDA-MB-231, and NIH3T3 cell lines. Using UHPLC-MS/MS, the metabolites present in each extract were identified. Finally, docking studies on sphingosine kinase 1 (PDB ID: 3VZB) of sphingosine were carried out.

RESULTS

The extracts from sargassum showed a greater effect in the antiproliferative assays in cells than in cytotoxic assays in Artemia salina. The ethanolic extract obtained from sargassum showed the best antiproliferative activity in MCF7 and MDA-MB-231 cells. Despite its antiproliferative effect on NIH3T3 cells, an additional extract is required indicating that this extract has compounds that could have a better effect on cancer cells in fibroblast (NIH3T3). The UHPLC-MS/MS of ethanolic and the ethyl acetate extract showed that these extracts have compounds such as sphinganine C16, N, N-Dimethylsphingosine compound, and that it could be possible that the effect observed is due to their metabolites which could be ligands for the sphingosine kinase 1 as demonstrated by docking studies.

CONCLUSION

The ethanolic extract obtained from sargassum has better antiproliferative activity, despite not having a cytotoxic effect in Artemia salina. The antiproliferative effect could be related to the sphinganine C16, N,NDimethylphingosine identified with more abundance by UHPLC-MS/MS. In addition, these metabolites could be targets of sphingosine kinase 1.

Sphingolipids in embryonic development, cell cycle regulation, and stemness - Implications for polyploidy in tumors

The aberrant biology of polyploid giant cancer cells (PGCC) includes dysregulation of the cell cycle, induction of stress responses, and dedifferentiation, all of which are likely accompanied by adaptations in biophysical properties and metabolic activity. Sphingolipids are the second largest class of membrane lipids and play important roles in many aspects of cell biology that are potentially relevant to polyploidy. We have recently shown that the function of the sphingolipid enzyme acid ceramidase (ASAH1) is critical for the ability of PGCC to generate progeny by depolyploidization but mechanisms by which sphingolipids contribute to polyploidy and generation of offspring with stem-like properties remain elusive. This review discusses the role of sphingolipids during embryonic development, cell cycle regulation, and stem cells in an effort to highlight parallels to polyploidy.

Sphingolipids and Lymphomas: A Double-Edged Sword

Lymphomas are a highly heterogeneous group of hematological neoplasms. Given their ethiopathogenic complexity, their classification and management can become difficult tasks; therefore, new approaches are continuously being sought. Metabolic reprogramming at the lipid level is a hot topic in cancer research, and sphingolipidomics has gained particular focus in this area due to the bioactive nature of molecules such as sphingoid bases, sphingosine-1-phosphate, ceramides, sphingomyelin, cerebrosides, globosides, and gangliosides. Sphingolipid metabolism has become especially exciting because they are involved in virtually every cellular process through an extremely intricate metabolic web; in fact, no two sphingolipids share the same fate. Unsurprisingly, a disruption at this level is a recurrent mechanism in lymphomagenesis, dissemination, and chemoresistance, which means potential biomarkers and therapeutical targets might be hiding within these pathways. Many comprehensive reviews describing their role in cancer exist, but because most research has been conducted in solid malignancies, evidence in lymphomagenesis is somewhat limited. In this review, we summarize key aspects of sphingolipid biochemistry and discuss their known impact in cancer biology, with a particular focus on lymphomas and possible therapeutical strategies against them.

Comparative Molecular and Immunoregulatory Analysis of Extracellular Vesicles from Candida albicans and Candida auris

Candida auris is a recently described multidrug-resistant pathogenic fungus that is increasingly responsible for health care-associated outbreaks across the world. Bloodstream infections of this fungus cause death in up to 70% of cases. Aggravating this scenario, the disease-promoting mechanisms of C. auris are poorly understood. Fungi release extracellular vesicles (EVs) that carry a broad range of molecules, including proteins, lipids, carbohydrates, pigments, and RNA, many of which are virulence factors. Here, we carried out a comparative molecular characterization of C. auris and Candida albicans EVs and evaluated their capacity to modulate effector mechanisms of host immune defense. Using proteomics, lipidomics, and transcriptomics, we found that C. auris released EVs with payloads that were significantly different from those of EVs released by C. albicans. EVs released by C. auris potentiated the adhesion of this yeast to an epithelial cell monolayer, while EVs from C. albicans had no effect. C. albicans EVs primed macrophages for enhanced intracellular yeast killing, whereas C. auris EVs promoted survival of the fungal cells. Moreover, EVs from both C. auris and C. albicans induced the activation of bone marrow-derived dendritic cells. Together, our findings show distinct profiles and properties of EVs released by C. auris and by C. albicans and highlight the potential contribution of C. auris EVs to the pathogenesis of this emerging pathogen.

IMPORTANCECandida auris is a recently described multidrug-resistant pathogenic fungus that is responsible for outbreaks across the globe, particularly in the context of nosocomial infections. Its virulence factors and pathogenesis are poorly understood. Here, we tested the hypothesis that extracellular vesicles (EVs) released by C. auris are a disease-promoting factor. We describe the production of EVs by C. auris and compare their biological activities against those of the better-characterized EVs from C. albicans. C. auris EVs have immunoregulatory properties, of which some are opposite those of C. albicans EVs. We also explored the cargo and structural components of those vesicles and found that they are remarkably distinct compared to EVs from C. auris’s phylogenetic relative Candida albicans.

The Role of Sphingolipids in Cancer Immunotherapy

Immunotherapy is now considered an innovative and strong strategy to beat metastatic, drug-resistant, or relapsing tumours. It is based on the manipulation of several mechanisms involved in the complex interplay between cancer cells and immune system that culminates in a form of immune-tolerance of tumour cells, favouring their expansion. Current immunotherapies are devoted enforcing the immune response against cancer cells and are represented by approaches employing vaccines, monoclonal antibodies, interleukins, checkpoint inhibitors, and chimeric antigen receptor (CAR)-T cells. Despite the undoubted potency of these treatments in some malignancies, many issues are being investigated to amplify the potential of application and to avoid side effects. In this review, we discuss how sphingolipids are involved in interactions between cancer cells and the immune system and how knowledge in this topic could be employed to enhance the efficacy of different immunotherapy approaches. In particular, we explore the following aspects: how sphingolipids are pivotal components of plasma membranes and could modulate the functionality of surface receptors expressed also by immune cells and thus their functionality; how sphingolipids are related to the release of bioactive mediators, sphingosine 1-phosphate, and ceramide that could significantly affect lymphocyte egress and migration toward the tumour milieu, in addition regulating key pathways needed to activate immune cells; given the renowned capability of altering sphingolipid expression and metabolism shown by cancer cells, how it is possible to employ sphingolipids as antigen targets.

Silver nanoparticles achieve cytotoxicity against breast cancer by regulating long-chain noncoding RNA XLOC_006390-mediated pathway

The specific cytotoxic effect of nanoparticles on tumor cells may be used in future antitumor clinical applications. Silver nanoparticles (AgNPs) have been reported to have potent cytotoxic effect, but the mechanism is unclear. Here, AgNPs were synthesized, and the particle average size was 63.1 ± 8.3 nm and showed a nearly circular shape, which were determined by transmission electron microscopy and field emission scanning electron microscopy. The selected area electron diffraction patterns showed that the nanoparticles were crystalline. The energy-dispersive X-ray spectrum proved that silver is the main component of nanoparticles. The AgNPs showed potent cytotoxicity in breast cancer cells, no matter whether they were tamoxifen sensitive or resistant. Next, we found that a long noncoding RNA, XLOC_006390, was decreased in AgNPs-treated breast cancer cells, coupled to inhibited cell proliferation, altered cell cycle and apoptotic phenotype. Downstream of AgNPs, XLOC_006390 was recognized to target miR-338-3p and modulate the SOX4 expression. This signaling pathway also mediates the AgNPs function of sensitizing tamoxifen-resistant breast cancer cells to tamoxifen. These results provide a new clue for the antitumor mechanism of AgNPs, and a new way for drug development by using AgNPs.

Brown Adipose Transplantation Improves Polycystic Ovary Syndrome-Involved Metabolome Remodeling

Polycystic ovary syndrome (PCOS) is a complex reproductive, endocrine, and metabolic disorder in reproductive-age women. In order to explore the active metabolites of brown adipose tissue (BAT) transplantation in improving the reproductive and metabolic phenotypes in a PCOS rat model, the metabolites in the recipient's BAT were explored using the liquid chromatography-mass spectrometry technique. In total, 9 upregulated and 13 downregulated metabolites were identified. They were roughly categorized into 12 distinct classes, mainly including glycerophosphoinositols, glycerophosphocholines, and sphingolipids. Ingenuity pathway analysis predicted that these differentially metabolites mainly target the PI3K/AKT, MAPK, and Wnt signaling pathways, which are closely associated with PCOS. Furthermore, one of these differential metabolites, sphingosine belonging to sphingolipids, was randomly selected for further experiments on a human granulosa-like tumor cell line (KGN). It significantly accelerated the apoptosis of KGN cells induced by dihydrotestosterone. Based on these findings, we speculated that metabolome changes are an important process for BAT transplantation in improving PCOS. It might be a novel therapeutic target for PCOS treatment.

Cancer stem cells and ceramide signaling: the cutting edges of immunotherapy

The multipotent, self renewing "cancer stem cells" (CSCs), a small population within tumor microenvironment facilitates transformed cells to grow and propagate within the body. The CSCs are discovered as resistant to the chemotherapeutic drug with distinct immunological characteristics. In recent years, immunologically targeting CSCs have emerged as an integral part of effective and successful cancer therapy. CSCs notably exhibit dysregulation in conventional sub-cellular sphingolipid metabolism. Recently, ceramide decaying enzymes have been shown to activate alternative ceramide signaling pathways leading to reduction in efficacy of the chemotherapeutic drugs. Therefore, a control over ceramide mediated modulations of CSCs offers an attractive dimension of effective cancer treatment strategy in future. In this review, we focused on the recent findings on broad spectrum of ceramide mediated signaling in CSCs within the tumor niche and their role in potential cancer immunotherapy.

Efficacy of Aloe-Vera Use for Prevention of Chemotherapy-Induced Oral Mucositis in Children with Acute Lymphoblastic Leukemia: A Randomized Controlled Clinical Trial

Oral mucositis can be caused by chemotherapy and can affect a patient's quality of life. Nowadays, to prevent chemotherapy-induced oral mucositis (CIOM) is a crucial point in palliative care centers. This trial aimed to assess the effectiveness of aloe-vera in that concept. The trial was accomplished at Hematology Department of Hospital of Children of Damascus University, Syria. Acute lymphoblastic leukemia (ALL) children were the population from which 26 children were enrolled in the study. They were aged between 3 and 6 years old and were randomly referred according to the intervention into two groups, Aloe-vera (AV) and sodium bicarbonate 5% (13 each). Spongeous sticks were used to help in applying the material on tongue, labial and buccal mucosa, lips, floor of the mouth, and hard palate. Two blinded external examiners evaluated oral mucosa weekly for up to 2 months using the World Health Organization grading scale. Mann-Whitney U test was used to analyze data. According to the observed findings, CIOM degrees were less severe in the aloe-vera group than in the sodium bicarbonate group. Statistically significant difference of occurrence of different CIOM degrees between groups was recorded in the 2nd, 3rd, 4th, and 7th weeks of follow-up period. Moreover, Mann-Whitney U test indicated that patients in the sodium bicarbonate group began CIOM sooner than those in the aloe-vera group with a statistically significant difference (p = .001). These findings show that topical application of aloe-vera solution is effective in the prevention of CIOM in ALL children.

C2-Ceramide-Induced Rb-Dominant Senescence-Like Phenotype Leads to Human Breast Cancer MCF-7 Escape from p53-Dependent Cell Death

Ceramide is a sphingolipid which regulates a variety of signaling pathways in eukaryotic cells. Exogenous ceramide has been shown to induce cellular apoptosis. In this study, we observed that exogenous ceramide induced two distinct morphologies of cell fate following C₂-ceramide treatment between the two breast cancer cell lines MCF-7 (wild type p53) and MDA-MB-231 (mutant p53) cells. The growth assessment showed that C₂-ceramide caused significant growth inhibition and apoptosis in MDA-MB-231 cells through down-regulating the expression of mutant p53 whereas up-regulating the expression of pro-apoptotic Bad, and the proteolytic activation of caspase-3. However, senescence-associated (SA)-β-galactosidase (β-gal) was regulated in MCF-7 cells after C₂-ceramide treatment. The results of proliferation and apoptosis assays showed that MCF-7 cells were more resistant to C₂-ceramide treatment compared to MDA-MB-231 cells. Furthermore, C₂-ceramide treatment induced a time-responsive increase in Rb protein, a key regulator of senescence accompanied with the upregulation of both mRNA level and protein level of SA-genes PAI-1 and TGaseII in MCF-7 but not in MDA-MB-231 cells, suggesting that some cancer cells escape apoptosis through modulating senescence-like phenotype. The results of our present study depicted the mechanism of C₂-ceramide-resistant breast cancer cells, which might benefit the strategic development of ceramide-based chemotherapeutics against cancer in the future.