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Acute myelogenous leukemia (AML) is a hematological malignancy marked by the accumulation of large numbers of immature myeloblasts in bone marrow. The overall prognosis in AML is poor; hence, there is a pressing need to improve treatment. Although the sphingolipid (SL) ceramide demonstrates known cancer suppressor properties, it’s mechanism of action is multifaceted. Our studies in leukemia and other cancers have demonstrated that when combined with the antiestrogen, tamoxifen, the apoptosis-inducting effect of ceramide is greatly enhanced. The goal of the present study was to establish whether a ceramide-tamoxifen regimen also affects autophagic-driven cellular responses in leukemia. Using the human AML cell line KG-1, we demonstrate that, unlike exposure to the single agents, combination C6-ceramide-tamoxifen upregulated LC3-II expression, inhibited the mTOR signaling pathway, and synergistically induced KG-1 cell death in an Atg5-dependent manner. In addition, colocalization of autophagosome and mitochondria, indicative of mitophagosome formation and mitophagy, was observed. Versatility of the drug regimen was confirmed by experiments in MV4-11 cells, a FLT3-ITD AML mutant. These results indicate that the C6-ceramide-tamoxifen regimen plays a pivotal role inducing autophagy in AML, and thus constitutes a novel therapeutic design.

Background Medicinal plants have been successfully used as an alternative source of drugs for the treatment of microbial diseases. Finding a novel treatment for malaria is still challenging, and various extracts from different wild desert plants have been reported to have multiple medicinal uses for human public health, this study evaluated the antimalarial efficacy of several Egyptian plant extracts. Methods We assessed the cytotoxic potential of 13 plant extracts and their abilities to inhibit the in vitro growth of Plasmodium falciparum (3D7), and to treat infection with non-lethal Plasmodium yoelii 17XNL in an in vivo malaria model in BALB/c mice. Results In vitro screening identified four promising candidates, Trichodesma africanum, Artemisia judaica, Cleome droserifolia, and Vachellia tortilis, with weak-to-moderate activity against P. falciparum erythrocytic blood stages with mean half-maximal inhibitory concentration 50 (IC50) of 11.7 μg/ml, 20.0 μg/ml, 32.1 μg/ml, and 40.0 μg/ml, respectively. Their selectivity index values were 35.2, 15.8, 11.5, and 13.8, respectively. Among these four candidates, T. africanum crude extract exhibited the highest parasite suppression in a murine malaria model against P. yoelii. Conclusion Our study identified novel natural antimalarial agents of plant origin that have potential for development into therapeutics for treating malaria.

Vinpocetine (Vin), a synthetic-derivative of Vincamine, monoterpenoid indole alkaloid, has been reported to have various medicinal benefits. The purpose of our study was to investigate the pivotal role of “nuclear factor erythroid 2-related factor-2” (Nrf2)-mediated antioxidant protection of Vin against H2O2 and paracetamol (APAP)-induced liver toxicity. For this purpose, a normal human hepatic cell line (L02 cells) was incubated with cytotoxic concentrations of H2O2 or APAP in the presence or absence of Vin. To evaluate the responses, MTS Cell Viability assay, immunoblotting, biochemical assays, and molecular docking approach were used. Viability analysis showed that treatment of L02 cells with Vin prevented the cytotoxicity induced by H2O2 and APAP. It was evidenced by the fact that Vin dumped H2O2- and APAP-cytotoxicity and reactive oxygen species (ROS) generation. The immuno¬blotting analysis shows that Vin increased Nrf2 expression along with the expression of target protein, heme oxygenase-1 (HO-1), and increased intracellular glutathione (GSH) level. Interestingly, we found that Vin could protect the protein expression-level of Nrf2, which indicated the prospective interaction between Vin and Keap1 protein. Additionally, molecular docking-study revealed that Vin competed with Nrf2 for Keap1-binding site, with hydrogen and stearic interactions. Collectively, Vin effectively protects against H2O2 and APAP-induced cytotoxicity via executing Nrf2-mediated restoration of antioxidative/oxidative balance. Meanwhile, Vin interrupts protein-protein interaction between Nrf2 and Keap1, which might also contribute to decrease Nrf2 degradation and stabilize protein expression. Thus, Vin-based adjuvant therapy may represent a smart drug regimen to mitigate drug-induced oxidative stress and liver injuries., EXCLI Journal; 20:Doc550; ISSN 1611-2156

The current study mainly aims at investigating the effectiveness of using Communicative Language Teaching (CLT) approach in developing students’ speaking skills at Sudanese secondary school levels from English language teachers’ perceptions. Also, the study seeks to find out the problems that hinder the teachers’ from implementing the CLT approach. To meet these aims and objectives the researcher employed a quantitative approach using a descriptive design. The researcher used the survey to collect data from the participants of the study. The random sampling technique was applied to select the sample out of all English language teachers at Omdurman Locality. Therefore, (100) female and male teachers have participated in this study. The information gained from the surveys was analyzed using the software Statistical Package for Social Sciences (SPSS). The study revealed the following findings: First of all, the majority of participants strongly agree that there is a positive relationship between teachers’ attitudes and effective usage of the communicative approach. The mains statements that gathered the highest level of response are: I think using CLT in my classroom helps my whole teaching process and using CLT in my class helps me share ideas and opinions with my learners. This means that most of the study participants assured that the use of CLT in the classrooms helped them to share the knowledge and facilitated their teaching process. Secondly, the majority of participants agree that there are effective factors that hinder teachers from using communicative approach to develop students speaking skills. The main statements which gathered their highest level of response are the following: Lack of authentic materials hinder the use of CLA in my and classroom size makes using CLT in my classroom more difficult. This clearly shows that the most effective factors that hinder teachers from implementing CLT in their classes are lacking of authentic material and classroom size. Finally, the majority of participants strongly agree that the communicative approach to develop students speaking skills – in general, and the main statements which gathered their highest level of response: Using CLA enhances students speaking skills, and I think using CLT motivates my student to speak accurately inside and outside the classroom. This result indicates that their participants of the study confirmed that using CLT in classroom enhanced their students speaking skill and motivated them to speak fluently.

The combination of daunorubicin (dnr) and cytarabine (Ara-C) is a cornerstone of treatment for acute myelogenous leukemia (AML); resistance to these drugs is a major cause of treatment failure. Ceramide, a sphingolipid (SL), plays a critical role in cancer cell apoptosis in response to chemotherapy. Here, we investigated the effects of chemotherapy selection pressure with Ara-C and dnr on SL composition and enzyme activity in the AML cell line HL-60. Resistant cells, those selected for growth in Ara-C- and dnr-containing medium (HL-60/Ara-C and HL-60/dnr, respectively), demonstrated upregulated expression and activity of glucosylceramide synthase, acid ceramidase (AC), and sphingosine kinase 1 (SPHK1); were more resistant to ceramide than parental cells; and displayed sensitivity to inhibitors of SL metabolism. Lipidomic analysis revealed a general ceramide deficit and a profound upswing in levels of sphingosine 1-phosphate (S1P) and ceramide 1-phosphate (C1P) in HL-60/dnr cells versus parental and HL-60/Ara-C cells. Both chemotherapyselected cells also exhibited comprehensive upregulations in mitochondrial biogenesis consistent with heightened reliance on oxidative phosphorylation, a property that was partially reversed by exposure to AC and SPHK1 inhibitors and that supports a role for the phosphorylation system in resistance. In summary, dnr and Ara-C selection pressure induces acute reductions in ceramide levels and large increases in S1P and C1P, concomitant with cell resilience bolstered by enhanced mitochondrial remodeling. Thus, strategic control of ceramide metabolism and further research to define mitochondrial perturbations that accompany the drug-resistant phenotype offer new opportunities for developing therapies that regulate cancer growth., This work was supported by National Institutes of Health Grant P01 CA171983 and by a grant from the Brody Brothers Foundation. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The authors declare that they have no conflicts of interest with the contents of this article.

Poor prognosis in patients with later stage colorectal cancer (CRC) necessitates the search for new treatment strategies. Ceramide, because of its role in orchestrating death cascades in cancer cells, is a versatile alternative. Ceramide can be generated by exposure to chemotherapy or ionizing radiation, or it can be administered in the form of short-chain analogs (C6-ceramide). Because intracellular P-glycoprotein (P-gp) plays a role in catalyzing the conversion of ceramide to higher sphingolipids, we hypothesized that administration of P-gp antagonists with C6-ceramide would magnify cell death cascades. Human CRC cell lines were employed, HCT-15, HT-29, and LoVo. The addition of either tamoxifen, VX-710, verapamil, or cyclosporin A, antagonists of P-gp, enhanced C6-ceramide cytotoxicity in all cell lines. In depth studies with C6-ceramide and tamoxifen in LoVo cells showed the regimen induced PARP cleavage, caspase-dependent apoptosis, mitochondrial membrane permeabilization (MMP), and cell cycle arrest at G1 and G2. At the molecular level, the regimen, but not single agents, induced time-dependent upregulation of tumor suppressor protein p53; however, introduction of a p53 inhibitor staved neither MMP nor apoptosis. Nanoliposomal formulations of C6-ceramide and tamoxifen were also effective, yielding synergistic cell kill. We conclude that tamoxifen is a favorable adjuvant for enhancing C6-ceramide cytotoxicity in CRC, and demonstrates uniquely integrated effects. The high frequency of expression of P-gp in CRC presents an adventitious target for complementing ceramide-based therapies, a strategy that could hold promise for treatment of resistant disease.

Although ceramide has potent tumor suppressor properties, its use in cancer therapeutics has been limited; this is mainly due to rapid metabolism of ceramide by cancer cells, the inability to attain therapeutic levels when ceramide-generating agents are employed, and the inherent insolubility of ceramide as a therapeutic. Our approach circumvents these disadvantages and provides advantages over existing methodologies. For example, rather than promoting intracellular ceramide generation by application of exogenous drugs that activate de novo and sphingomyelinase pathways, we have chosen to administer ceramide exogenously in the form of short-chain C6-ceramide nanoliposomes; this overcomes solubility issues and improves uptake. In addition, nanoliposomes are efficient platforms for delivering other hydrophobic chemotherapeutics. The antiestrogen tamoxifen was selected for our studies because of its unusual “off-target” actions, which include inhibition of ceramide metabolism at glycosylation and hydrolysis. Blocking these junctures increases C6-ceramide intracellular residence time and diminishes production of sphingosine 1-phosphate, a mitogenic lipid derived via the action of ceramidase and sphingosine kinase. Hence, C6-ceramide and tamoxifen make up a versatile drug duo. Using in vitro models of human colon and breast cancer, acute mylogenous leukemia (AML), and melanoma, we show that simultaneous administration of nanoliposomal C6-ceramide and tamoxifen potently and synergistically decreased cell viability, compared to the single agents. The mix induced caspase-dependent apoptosis, cell cycle arrest at G1 and G2, upregulation of JNK, p38, and p53, and downregulation of Akt and survivin. In triple negative, hormone-insensitive breast cancer cells, C6-ceramide-tamoxifen induced cell cycle arrest, caspase-dependent apoptosis, and lysosomal and mitochondrial membrane permeability. Evaluation of single agents showed that tamoxifen elicited lysosomal membrane permeability and inhibited acid ceramidase. We have obtained similar results in in vitro models of human melanoma and AML. In an in vivo retroviral transduced murine AML model, the combination lowered leukemia burden in spleen and marrow. The combination also perpetuated synergistic increases in long-chain ceramides, likely compounding the overall ceramide effect. Of interest regarding in vivo utility, the major metabolites of tamoxifen, N-desmethyltamoxifen and 4-hydroxytamoxifen, were effective in combination with C6-ceramide. Our findings show that tamoxifen magnifies the antiproliferative effects of C6-ceramide via aggregate mechanisms. This proficient, ceramide-based nanoliposomal drug regimen may have potential as an effective anticancer therapeutic. Supported by NIGMS 77391; ABC's, Los Angeles; Fashion Footwear Association of New York Charitable Foundation. Citation Format: Samy A.F. Morad, Jonathan C. Levin, Noha Abdelmageed, Mark Kester, Sriram S. Shanmugavdlandy, Robert F. Paulson, Daniel W. Rosenberg, James P. Madigan, Myles C. Cabot. Tamoxifen amplifies antitumor impact of nanoformulated ceramide- pan efficacy in a myriad of tumor cell types. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2027. doi:10.1158/1538-7445.AM2013-2027