Concentrations Of Salinomycin Research Articles

Natural and modified clays as low-cost and ecofriendly materials to remove salinomycin from environmental compartments

Antibiotics in the environment represent a substantial pollution threat. Among these emerging pollutants, ionophore anticoccidials are of special concern due to their potential ecological impact, persistence in the environment, and role in promoting antimicrobial resistance. To investigate the adsorption/desorption of the ionophore antibiotic salinomycin (SAL) on/from raw and modified clay adsorbents, batch-type experiments were performed using 0.5 g of clay adsorbent mixed with 10 mL of increasing doses of SAL solutions for each sample, at room temperature, with a contact time of 24 h. All measurements were conducted in triplicate employing HPLC-UV equipment. Three different natural (raw) and modified clay samples were investigated, which were denominated as follows: AM (with 51% calcite), HJ1 (with 32% kaolinite), and HJ2 (with 32% microcline). The experiments were carried out using three pH ranges: between 3.33 and 4.49 for acid-activated clays, 8.39–9.08 for natural clays, and 9.99–10.18 for base-activated clays. The results indicated that, when low concentrations of the antibiotic were added (from 5 to 20 μmol L−1), more than 98% of SAL was strongly adsorbed by almost all clays, irrespective of the physicochemical and mineralogical composition of the clays or their pH values. When higher SAL concentrations were added (40 and 100 μmol L−1), the adsorption of the antibiotic showed pH-dependent ligand adsorption mechanisms: (i) highly decreased as the pH raised (for the raw and base-activated AM and HJ1 clays), while (ii) slightly decreased as the pH decreased (on the acid-activated clays). Among the adsorption equations tested (Freundlich, Langmuir, and Linear), the Freundlich model was identified as the most suitable for fitting the data corresponding to SAL adsorption onto the studied clays. SAL desorption from clays was consistently below 10% for all the clay samples, especially for the acid-activated clays, due to cation bridging adsorption mechanisms, when the lowest concentration of the antibiotic was added. Additionally, it should be stressed that the desorption values can increase with rising SAL concentrations, but they always remain below 20%. Overall, the clays here investigated (both raw and modified) provide a cost-effective and efficient alternative for the removal of the veterinary anticoccidial antibiotic SAL, with potential positive and practical implications in environmental remediation and antibiotic pollution management, particularly by serving as amendments for contaminated soils to enhance their adsorption capacities against SAL. Additionally, using these clays in water treatment processes could improve the efficiency of mitigating antibiotic contamination in aquatic systems.

Salinomycin alleviates osteoarthritis progression via inhibiting Wnt/β-catenin signaling

Osteoarthritis (OA) is the most prevalent degenerative whole-joint disease characterized by cartilage degeneration, synovial hyperplasia, osteophyte formation, and subchondral bone sclerosis. Currently there are no disease-modifying treatments available for OA because its etiology and pathogenesis are largely unknown. Here we report that a natural carboxylic polyether ionophore that is used as an anti-tumor drug, salinomycin (SAL), may be a promising therapeutic drug for OA in the future. We found that SAL showed no cytotoxicity on mouse chondrocytes and displayed a protective effect against interleukin-1β (IL-1β), in cultured mouse chondrocytes and cartilage explants. Treatment with low SAL concentrations directly upregulated the anabolism factors collagen II and aggrecan, while it inhibited the catabolic factors matrix metalloproteinase-13 (MMP13) and metalloproteinase with thrombospondin motifs-5 (ADAMTS5) to protect against extracellular matrix (ECM) degradation, and also suppressed inflammatory responses in mouse chondrocytes. Furthermore, SAL reduced the severity of OA-associated changes and delayed cartilage destruction, subchondral bone sclerosis, and osteophyte formation in a destabilized medial meniscus (DMM) surgery-induced mouse OA model. Mechanistically, a low SAL concentration induced anabolism and inhibited catabolism in chondrocytes via inhibiting Lrp6 phosphorylation and Wnt/β-catenin signaling. Our results suggested that SAL may serve as a potential disease-modifying therapeutic against OA pathogenesis.

Salinomycin mediated therapeutic targeting of circulating stem like cell population in oral cancer

CD44+ circulating tumor stem cells (CTSCs) have been significantly associated with aggressiveness, resistance and poor prognosis of oral cancer patients. Thus, targeted elimination of these CTSCs could be a new conceptual framework for enhancing the therapeutic outcome of patients. Docking of potential investigational molecules and simulation results identified Salinomycin as a potential lead compound that could effectively inhibit CD44 receptor. To assess the cytotoxic effect, immuno-magnetically sorted circulatory CD44+ cells were subjected to increasing concentrations of 5FU, Cisplatin and Salinomycin. Salinomycin demonstrated significant cytotoxic effect towards the CD44+ subpopulation in a dose and time dependent manner. Further the effect of these compounds was investigated on apoptosis, cell cycle, signaling pathways and gene expression profiles using MuseTM flow cytometer and Real-Time PCR. It was observed that mRNA expression patterns of CD44v6, Nanog, AKT1, CDKN2A and β-catenin of Salinomycin treated CD44+ cells. Moreover, Salinomycin significantly induced programmed cell death by inducing G2/M cell cycle arrest and inhibiting MAPK/PI3K pathways in this chemo-resistant population. Thus, this study demonstrated the potential of Salinomycin to target the chemo-resistant circulating CD44 population by attenuating its proliferation and survival. Communicated by Ramaswamy H. Sarma

Effects of salinomycin on proliferation and apoptosis of oral squamous cell carcinoma

To investigate the effects of salinomycin on the proliferation and apoptosis of oral squamous carcinoma cells and to further understand the mechanisms of these effects. The human oral squamous carcinoma cell line CAL-27 was cultured in different concentrations of salinomycin and cisplatin. After co-culture with 0, 1, 2, 4, 8, 16 and 32 μmol/L salinomycin or 0, 1.25, 2.5, 5, 10, 20, 40 and 80 μmol/L cisplatin for 24 hours and 48 hours, the proliferation of oral squamous carcinoma cells were detected by cell counting kit-8(CCK-8) assay. After being exposed to 0, 2, 4, 8 μmol/L salinomycin and 0, 5, 10, 20 μmol/L cisplatin for 48 hours, the cell cycle of oral squamous carcinoma cells was detected by flow cytometry assay, and Western blot analysis was performed to analyze the expressions of cysteine-containing aspartate-specific proteases-3(Caspase-3), cysteine-containing aspartate-specific proteases-9(Caspase-9), poly ADP-ribose polymerase (PARP), protein kinase B (Akt) and phosphorylated protein kinase B (p-Akt) protein in oral squamous carcinoma cells. Both salinomycin and cisplatin significantly inhibited the proliferation of oral squamous cell carcinoma CAL-27 cells in a time- and dose-dependent manner. However, compared with the first-line chemotherapeutic drug cisplatin, salinomycin showed stronger anti-proliferation activity in oral squamous carcinoma cells than cisp-latin (P < 0.001). After being exposed to 8 μmol/L salinomycin, CAL-27 cells exhibited markedly higher proportion in quiescent/ first gap phases (40.40%±1.99% vs. 64.46%±0.90%, P < 0.05), and had a significantly lower proportion in synthesis phases and second gap / mitosis phases (24.32%±2.30% vs. 18.73%±0.61%, P < 0.05; 35.01%±1.24% vs. 16.54%±1.31%, P < 0.05) compared with the dimethyl sulfoxide control group; moreover cisplatin didn't show cell-cycle specific effect on CAL-27. Western blot proved that salinomycin could up-regulate the expressions of Caspase-3 and Caspase-9 protein in oral squamous cell carcinoma CAL-27 cells (P < 0.05). At the same time, the levels of PARP, Akt and p-Akt protein were down-regulated (P < 0.05). Compared with cisplatin, salinomycin has a better inhibitory effect on the proliferation of oral squamous carcinoma cells and blocks the cell cycle process at the quiescent / first gap phase. At the same time, salinomycin could trigger apoptosis of oral squamous carcinoma cells and the mechanism is associated with the Akt/p-Akt signaling pathway.

Combination of Salinomycin and AZD3463 Reveals Synergistic Effect on Reducing the Viability of T98G Glioblastoma Cells.

Salinomycin, an ionophore antibiotic, is known to be an effective agent in reducing the viability of Glioblastoma (GBM) cells. The combination of salinomycin with other chemotherapeutic drugs would help to overcome the drug resistance of GBM cells. This study aims to test the combinatorial effect of salinomycin and AZD3463 in T98G GBM cells. The cytotoxic effects of drugs on T98G GBM cells were determined by using WST-8 assay. Flow cytometry was used to identify apoptosis and cell cycle profiles after treatments. Real-time PCR was used to portray mRNA expression profiles of genes in the Wnt-signaling pathway after treatments. IC50 concentrations of AZD3463 and salinomycin were 529nM and 7.3μM for 48h, respectively. The combination concentrations of AZD3463 and salinomycin were 3.3μM and 333nM, respectively. The combination treatment showed a synergistic effect on reducing the viability of GBM cells. AZD3463, salinomycin, and their combination induced apoptosis in 1.2, 1.4, and 3.2 folds, respectively. AZD3463 and the combination treatment induced the cell cycle arrest at the G1 phase. Salinomycin and AZD3463 treatments, either alone or in combination, resulted in the downregulation or upregulation of mRNA expression levels of genes in the Wntsignaling pathway. Salinomycin, AZD3463, and their combination may inhibit proliferation and induce apoptosis in GBM cells due to a decrease in expression levels of genes acting in both the canonical and non-canonical Wnt signaling pathways. The Wnt signaling pathway may be involved in salinomycin-AZD3463 drug interaction.

Behavior of ionophore antibiotics in aquatic environments in Argentina: The distribution on different scales in water courses and the role of wetlands in depuration

We studied for the first time three ionophore anticoccidial drugs: monensin (MON), lasalocid (LAS), and salinomycin (SAL) as emerging pollutants originating from animal and plant husbandry in surface waters (n = 89) in one of the most extensive hydrological basins in South América (Del Plata basin). The soluble fraction of ionophores was pretreated by solid-phase extraction and analyzed by LC-MS/MS at a limit of detection of 1.7 ng·L−1. A statistical approach noted the need to report parameters calculated by methods based on the number of observations and the censorship percentage over substitution methods for more precise estimations of environmental data with a high percentage of left-censored data. Water collectors adjacent to intensive-husbandry facilities, placed in direct runoffs from animal excreta, or in wastewater emissions contained median concentrations of MON and SAL approximately 70 times higher than those found in regional tributaries and main courses of 5 sub-basins of the pampas and mesopotamic regions, thus exhibiting a relevance to other similar agricultural pollutants widely reported as pesticides. Chemical speciation of these compounds in surface water was characterized especially for MON and SAL, where the pH and chemical oxygen demand of the natural water body was associated with the concentration of the soluble fraction. The concentrations in abundant rivers such as the Gualeguay deliver a contribution to a natural wetland such as the Paraná-River delta, which registered only one sample with a [MON] ≤ the limit of quantification. Since wetlands possess a limited removal capability, these affluent contributions recorded strongly indicate that attention must be paid to the development of guidelines involving quality criteria for assessing the impact of ionophore antibiotics on such ecosystems.

The Triple-negative Breast Cancer Cell Line MDA-MB 231 Is Specifically Inhibited by the Ionophore Salinomycin.

Tumour cells of the profile CD44+/CD24low/- have a high tumorigenic potential. Salinomycin can specifically inhibit the growth of these cells. Herein, we investigated the effects of salinomycin on the viability and migration of triple negative breast cancer cells. We analysed two cell lines: i) triple-negative MDA-MB 231 breast cancer cells and ii) a cytokeratin 18-transfected, re-differentiated subclone of the MDA-MB 231 cell line. The viability was determined using an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test, and the migration was determined using 24-h videography. The expression of oestrogen receptor was determined using immunohistochemistry. Salinomycin reduces all migration parameters in MDA-MB 231 cells. A significant correlation was found between increasing salinomycin concentrations and loss of cell viability, which was significantly less noticeable in the transfected control cells. With salinomycin there is a specific inhibition of MDA-MB 231 cells. Since MDA-MB 231 has over 90% cells with the profile CD44+/CD24low/-, these might represent a possible point of attack for salinomycin.

Coccidiostats in milk: development of a multi-residue method and transfer of salinomycin and lasalocid from contaminated feed

ABSTRACTA confirmatory multi-residue method was developed for the determination in milk of 19 coccidiostats (amprolium, arprinocid, clazuril, clopidol, decoquinate, diclazuril, ethopabate, halofuginone, lasalocid, maduramicin, monensin, narasin, nicarbazin, nequinate, robenidine, salinomycin, semduramicin, toltrazuril sulfone and toltrazuril sulfoxide). Sample preparation utilising extraction with organic solvent and clean up by SPE and freezing was found reliable and time-efficient. Optimised chromatography and MS conditions with positive and negative ESI achieved sufficient sensitivity and selectivity. Validation experiments has proven method usefulness for routine analysis of coccidiostats in milk samples. An on-farm study conducted on dairy cows fed with experimentally contaminated feed with salinomycin and lasalocid showed negligible transfer to milk. No residues of lasalocid were found in collected samples. Salinomycin was found only in 5 of 168 samples analysed, while the concentrations of salinomycin in those samples (0.119–0.179 µg kg–1) was significantly below the limit of salinomycin in milk set by European Union legislation. Such low concentrations of both coccidiostats cannot be explained by conjugation during dairy cows’ metabolism, as shown by experiments with enzymatic hydrolysis.

Effects on health, performance, and tissue residues of the ionophore antibiotic salinomycin in finishing broilers (21 to 38 d).

A study was conducted to evaluate the effects of feeding salinomycin at the recommended prophylactic level, and at 2 and 3 times this level, to finishing male broilers (d 21 to 38). Four treatment groups were given the experimental diets containing 0, 60, 120, or 180 parts per million (ppm) salinomycin from d 21 to 38. Performance, relative organ weights, selected serum enzymes, and salinomycin residues in liver, muscle, and serum were determined. Salinomycin supplementation had no effect on body weight, feed intake, or feed conversion, and caused no overt signs of toxicity. After a week of being fed the salinomycin diets, the serum activity of aspartate aminotransferase was significantly increased in chickens fed 180ppm compared with controls. These birds also showed microscopic lesions in breast and thigh muscles, but not in cardiac muscle. Salinomycin residues were not detected by high-performance liquid chromatography coupled to tandem mass spectrometry in liver or muscle samples from the birds fed 0, 60, or 120ppm salinomycin. However, chickens fed 180ppm salinomycin had detectable levels in liver and muscle above the maximum residue level of 5μg/kg established by the European Union. All birds fed salinomycin had salinomycin in their sera with levels ranging from N.D. (not detected) in the controls to 24.4 ± 7.9, 61.4 ± 18.9, and 94.5 ± 9.1μg/L for salinomycin dietary levels of 60, 120, and 180ppm, respectively. Serum salinomycin concentration was linearly related with salinomycin content in feed (y = 0.584x - 10, r2 = 0.999). The results showed that even at 3 times the prophylactic level, salinomycin does not induce clinical toxicosis or mortality. No salinomycin residues were found in edible tissues at the recommended dietary level or at 2 times this level. However, salinomycin was detected in serum regardless of the dietary level. A simple method for salinomycin determination in serum is described which can be used as a marker of exposure and/or to predict levels in the diet.

Effects of Salinomycin and Everolimus on Breast Cancer Stem Cells in Hypoxia

Cancer stem cells (CSCs) are a collection of small numbers of cells that have the potential to induce all cell types within the tumor mass and have self-renewal capacity. Today, the reasons for the failure of conventional cancer therapies lie in the fact that they are unable to target cancer stem cells. Targeting the cancer stem cell is thought to provide a very important and revolutionary advance in cancer cell targeting and therapy Tumor hypoxia is a characteristic of solid tumors and has been associated with poor prognosis and resistance to radiotherapy and chemotherapy. HIF-1 (Hypoxia Inducible Factor-1) is the major transcription factor activated in hypoxic conditions and allows transcriptional activation of various genes that are effective for the adaptation of the cell to the hypoxic condition. Experimental studies have provided evidence that also hypoxia and HIF-1α promote the cancer stem cell phenotype and targeting of HIF-1α may reduce or eliminate cancer stem cells. Breast cancer is the most common form of cancer in women worldwide and affects 10% of the world's female population. 25% to 30% of patients with invasive breast cancer still die from this disease. The recurrence frequency of the disease varies between 60% and 80% within the first 3 years after treatment. In order to target breast cancer stem cells more effectively, in this study we aimed to reveal whether the hypoxic conditions in the tumor, which act as the stem cell production area, at the same time creates resistance to therapy. Thus, we evaluated effect of CSCs targeting agent Salinomycin alone or in combination with Everolimus which is an m-TOR and HIF-1α inhibitor on parental MCF-7 and MDA-231 breast cancer cells and their isolated CSCs in hypoxic conditions. Here it is presented that starting with 2 mM, increased concentrations of salinomycin significantly inhibits proliferation and induce apoptosis in hypoxia, in both parental MCF-7 and MDA-231 breast cancer cells and in their isolated CSCs. The most effective concentration of salinomycin was 10 mM and induced around 35% and 45% of apoptosis in both parental MCF-7 and MDA-231 and their isolated CSCs, respectively. Whereas everolimus alone was not as effective as salinomycin, as 25 mM everolimus induced 30% and 15% of growth inhibition or apoptosis in both parental and CSCs of MCF-7 and MDA-231 cellsin hypoxia, respectively. When lower concentrations of salinomycin (2mM) and everolimus (5mM) was used in combination they show synergistic effect and able to inhibit proliferation at least 35% and 45% in both parental and CSCs of MCF-7 and MDA-231 cells in hypoxia, respectively. Similar results were also obtained for induction of apoptosis in response to salinomycin + everolimus treatment in hypoxia in both parental and CSCs of MCF-7 and MDA-231 cells. Hence using lower concentrations of salinomycin and everolimus together may provide an effective targeting strategy for hypoxic CSCs and may contribute to the development of novel strategies for therapeutic intervention in breast cancer.

Abstract A067: Salinomycin kills not only circulating epithelial tumor cells (CETCs) but also circulating cancer stem cells (cCSC) and may potentially prevent progression in patients with breast cancer

Abstract Background: Recently the hypothesis has been proposed that a more aggressive subpopulation of circulating tumor cells, circulating cancer stem cells, are the source of metastatic spread from the primary tumor. These cells are considered to be responsible for treatment relapse and have therefore become a major target in cancer research. The antibiotic salinomycin isolated from Streptomyces albus is the best established cancer stem cell inhibitor and has been shown to reduce the expression of markers for stemness and spheroid-forming ability. The mechanisms of the anticancer effects remain unclear. In this study, we evaluated the cytotoxic effect of salinomycin on CETCs and tumorspheres cultured from cCSC. Methods: 20 patients with breast cancer in different stages of disease were included. The determination of CETCs and cCSC was performed using Maintrac® method and tumorsphere forming assay, respectively. To evaluate the cytotoxic effect of salinomycin on CETCs and spheroids, they were exposed to different concentrations of salinomycin in short time culture for different periods of time. Results: 79% of patients had detectable CETCs and sphere formation was observed in 74% of breast cancer patients. Interestingly, growth of spheroids was detected also in patients without CETCs. The number of tumorspheres increased significantly with tumor progression, especially with presence of metastasis. Treatment with salinomycin showed an 80% reduction in spheroid formation compared with control. Salinomycin reduced the viability of spheroids in a dose-dependent manner. Salinomycin had a stronger cytotoxic effect on CETCs in nonmetastatic as compared to metastatic patients (median of dead CETCs 85% vs. 34%, p&amp;lt;0.001). Similarly, patients without chemotherapy responded better to salinomycin treatment than patients after several lines of chemotherapy (median of dead CETCs 87%vs.35%, p&amp;lt;0.001). Conclusion: Using a method for cultivation of tumorspheres from peripheral blood of cancer patients and an effective in vitro platform for screening anticancer stem cells drugs was developed. Thus it could be shown that salinomycin targets not only more differentiated circulating cancer cells but also cancer stem cells from peripheral blood. It may evolve as a novel and promising therapeutic strategy for future cancer treatment. Citation Format: Monika Pizon, Dorothea Schott, Ulrich Pachmann, Katharina Pachmann, Norbert Szalus. Salinomycin kills not only circulating epithelial tumor cells (CETCs) but also circulating cancer stem cells (cCSC) and may potentially prevent progression in patients with breast cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A067.

The effect and mechanism of salinomycin on the proliferation and apoptosis of adrenal cortical carcinoma SW13 cell line

Objective To study the effect and mechanism of salinomycin on the cell proliferation, cell cycle, cell apoptosis and invasion of human adrenal cortical carcinoma SW13 cells. Methods Culture SW13 cell line in vitro and treated with salinomycin (30.000, 20.000, 10.000, 5.000, 2.500, 1.250, 0.625, 0 μmol/L) for 24, 48, 72 and 96 h, then use cell counting kit-8 (CCK-8) to assay cell proliferation. The cell treated with salinomycin cycle and apoptosis were determined with flow cytometry. Use transwell invasion experiment to assay invasive ability. The expression of β-catenin and B-cell lymphoma/leukemia-2 (bcl-2) were detected by Western blotting. Results After treated with different concentrations of salinomycin 24, 48, 72 and 96 hours, the proliferation of SW-13 cells were significantly inhibited and showed a time and concentration dependence and the corresponding 50% inhibitory concentration (IC50) was 25.65, 7.97, 2.89, 0.40 μmol/L. Flow cytometry showed that 4, 8 μmol/L group and control group G1-period cells percentage were (66.250±1.162)%, (71.693±0.849)%, (59.837±3.043)% and the difference was statistically significant. The apoptosis rates were respectively 9.9%, 30.3%, 3.4% and have significant difference. Transwell invasion experiment showed that the number of invasive cells were 66.800±5.263, 30.400±2.881, 17.600±3.050 respectively and have significant difference. The expressions of β-catenin and anti-apoptosis bcl-2 proteins were down-regulated. Conclusion Salinomycin may significantly inhibit cell proliferation, cell cycle, invasive ability and induce apoptosis of human adrenal cortical carcinoma SW13 cells by disturb Wnt/β-catenin signal pathway and down-regulate bcl-2 anti-apoptosis protein. Key words: Salinomycin; Adrenal cortical carcinoma; SW13 cell; Proliferation; Cycle; Apoptosis; Invasion

Salinomycin reduces the viability of circulating epithelial tumor cells (CETCs) and tumorspheres cultured from circulating cancer stem cells (cCSC) and may potentially prevent progression in patients with solid cancer.

e23143 Background: Recently the hypothesis has been proposed that a more aggressive subpopulation of circulating tumor cells, circulating cancer stem cells are the source of metastatic spread from the primary tumor. These cells are considered to be responsible for treatment relapse and have therefore become a major target in cancer research. The antibiotic Salinomycin has been shown to reduce the expression of markers for stemness and spheroid-forming ability. In this study, we evaluated the cytotoxic effect of salinomycin on CETCs and tumorspheres cultured from cCSC. Methods: 20 patients with solid tumors in different stages of disease were included. The determination of CETCs and cCSC was performed using maintrac method and tumorsphere forming assay, respectively. To evaluate the cytotoxic effect of salinomycin on CETCs and spheroids they were exposed to different concentrations of salinomycin in short time culture for different periods of time. Results: 80% of patients had detectable CETCs but sphere formation was observed in 95% of solid cancer patients. Growth of spheroids was detected also in patients without CETCs. The number of tumorspheres increased significantly with tumor progression. Treatment with salinomycin showed an 80% reduction in spheroid formation compared with control. Salinomycin reduced the viability of spheroids in a dose–dependent manner. Salinomycin had stronger cytotoxic effect on CETCs in non-metastatic as compared to metastatic patients (median of dead CETCs 85% vs. 34%, p &lt; 0.001). Patients without chemotherapy responded better to salinomycin treatment than patients after several lines of chemotherapy (median of dead CETCs 87%vs.35%, p &lt; 0.001) Conclusions: Using a method for cultivation of tumorspheres from blood of cancer patients and an effective in vitro platform for screening anti-cancer stem cells drugs was developed. Thus it could be shown that salinomycin targets not only more differentiated circulating cancer cells but also cancer stem cells from peripheral blood. It may evolve as a novel and promising therapeutic strategy for future cancer treatment

Growth performance and safety of meat from cattle feedlot finished with salinomycin in the diet

This study aimed to evaluate the performance, carcass characteristics, serum parameters, the residual depletion in the beef and the economic viability of termination steers with salinomycin in the diet. Were confined 32 animals fed with diet consisting of corn silage and concentrate (50:50) or not added salinomycin (120 mg animal d-1). The design was completely randomized with 8 repetions. The use of salinomycin improved weight gain (1.582 vs 1.304 kg) and feed conversion (6.16 vs 7.25 kg kg-1). There were no significant changes in feed intake (9.52 vs 9.25 kg animals d-1) in serum parameters, nor in the apparent digestibility of the diet. The 16-hour grace period before slaughter expressed salinomycin concentrations below 0.25 µg kg-1 in the organs and edible tissues below the values allowed by law. Animals finished with salinomycin showed better hot carcass weight (287.76 vs 275.81 kg) and better economic results, an increase of R$ 84.20 per animal in the profit margin. The use of salinomycin for feedlot steers promoted improvements in the production and economic performance without harming the health of animals and consumers, because they were not detected significant residues in edible tissues

525 - Salinomycin affects Golgi apparatus function in cancer stem-like cells

Background: Cancer stem cells (CSC) are an immortal tumor-initiating population that can self-renew and has pluripotent capacity. Despite their small number, CSCs are believed to be critical for tumor initiation, progression and metastasis, as well as for the treatment failure and disease relapse. CSCs have been confirmed to exist in various types of tumors which include leukemia as well as various solid cancers. There are several obstacles involved with CSC research among which are their low number within tumor cell population and their relative instability in culture. Recently, a breast CSC model was established by experimental induction of epithelial to mesenchymal transition (EMT) in immortalized human mammary epithelial cells (HMLE). Using this model salinomycin was identified to be selectively toxic towards epithelial CSCs. Salinomycin is a K+/H+ exchanger that can affect cation transport across different membranes present in the cell. However the exact mechanism of the observed selectivity remains largely unknown. We have noticed that salinomycin affects posttranslational modifications of membrane proteins in the fore mentioned CSC model. This lead us to the hypothesis that salinomycin induces Golgi apparatus stress that affects secretory pathway which may represent a key vulnerability of EMT cells. Of note, monensin, another ionophore with chemical structure similar to that of salinomycin, is a well described inhibitor of Golgi function. Materials and Methods: We used HMLE cells with knocked-down E-cadherin (HMLEshEcad) that went through EMT and display characteristics of stem cells. To test our hypothesis we performed western blotting, confocal microscopy and flow cytometry after staining with fluorescently labeled Golgirelated antibodies. Results: The treatment of stem-like HMLEshEcad cells with submicromolar concentrations of salinomycin causes dysfunctional maturation of N-cadherin. In addition, we observed similar changes in processing of other plasma membrane proteins that could be accounted for aberrant Golgi apparatus function. The same effect was not observed in control cells. Immunostaining confirmed changes of Golgi apparatus morphology and function. Conclusion: Our results indeed point that salinomycin differentially affects mesenchymal and epithelial cells due to their different dependence on the Golgi apparatus function. We believe that agents that promote endoplasmic reticulum and Golgi apparatus malfunction should be further explored for their potential to selectively eradicate cancer cells that have undergone an EMT.

Stacking Time and Aluminum Sulfate Effects on Polyether Ionophores in Broiler Litter.

The use of ionophores as antiparasitic drugs plays an important role in US poultry production, especially in the broiler () industry. However, administered ionophores can pass through the bird's digestive system and appear in broiler litter, which, when applied to agricultural fields, can present an environmental hazard. Stacking (storing or stockpiling) broiler litter for some time might decrease the litter ionophore concentrations before land application. Because ionophores undergo abiotic hydrolysis at low pH, decreasing litter pH with acidic aluminum sulfate (alum) might also decrease ionophore concentrations. We assessed the change in ionophore concentrations in broiler litter in response to the length of time broiler litter was stored (stacking time) and alum addition. We spiked broiler litter with monensin and salinomycin, placed alum-amended litter (∼pH 4-5) and unamended litter (∼pH 8-9) into 1.8-m bins, and repeatedly sampled each bin for 112 d. Our findings showed that stacking broiler litter alone did not have an impact on monensin concentration, but it did slowly reduce salinomycin concentration by 55%. Adding alum to broiler litter reduced monensin concentration by approximately 20% relative to unamended litter, but it did not change salinomycin concentration. These results call for continued search for alternative strategies that could potentially reduce the concentration of ionophores in broiler litter before their application to agricultural soils.

Alum and Rainfall Effects on Ionophores in Runoff from Surface-Applied Broiler Litter.

Polyether ionophores, monensin, and salinomycin are commonly used as antiparasitic drugs in broiler production and may be present in broiler litter (bird excreta plus bedding material). Long-term application of broiler litter to pastures may lead to ionophore contamination of surface waters. Because polyether ionophores break down at low pH, we hypothesized that decreasing litter pH with an acidic material such as aluminum sulfate (alum) would reduce ionophore losses to runoff (i.e., monensin and salinomycin concentrations, loads, or amounts lost). We quantified ionophore loss to runoff in response to (i) addition of alum to broiler litter and (ii) length of time between litter application and the first simulated rainfall event. The factorial experiment consisted of unamended (∼pH 9) vs. alum-amended litters (∼pH 6), each combined with simulated rainfall at 0, 2, or 4 wk after litter application. Runoff from alum-amended broiler litter had 33% lower monensin concentration ( < 0.01), 57% lower monensin load ( < 0.01), 48% lower salinomycin concentration ( < 0.01), and 66% lower salinomycin load ( < 0.01) than runoff from unamended broiler litter when averaged across all events of rainfall. Ionophore losses to runoff were also less when rainfall was delayed for 2 or 4 wk after litter application relative to applying rainfall immediately after litter application. While the weather is difficult to predict, our data suggest that ionophore losses in runoff can be reduced if broiler litter applications are made to maximize dry time after application.

Combination of cell culture and qPCR to assess the efficacy of different anticoccidials on Eimeria tenella sporozoites.

Three in vitro studies were designed to develop an assay for anticoccidial efficacy by use of laboratory (Houghton) and field (T-376) Eimeria tenella strains. In study (1), minimum inhibitory concentrations (MICs) of monensin (Mon), maduramicin (Mad), salinomycin (Sal), and lasalocid (Las) were determined that are able to inhibit more than 50% of sporozoites in host cell (Madin-Darby bovine kidney (MDBK)) penetration and more than 95% of Houghton sporozoites development to mature merozoites (treatment time 24 h) using quantitative real-time PCR (qPCR). MICs were 0.5, 2.5, 1, and 0.5 μg/ml for Mon, Mad, Sal, and Las, respectively. Applying the previous MIC on T-376 strain revealed a different sensitivity profile. Mad reduced T-376 gene copies by only 89.3% after 96 h of infection. In study (2), Houghton strain sporozoites were incubated with MIC of the different tested ionophores for 2 and 4 h, respectively; afterwards, their ability to invade MDBK cells was determined using phase-contrast microscopy and qPCR. Treatment of sporozoites with ionophores for 4 h resulted in significant inhibition of invasion compared with non-treated parasites as assessed both by microscopy as well as qPCR. Inhibition rates for Mon, Mad, Sal, and Las were 90.2, 75.0, 88.3, and 82.6% using phase-contrast microscopy and 83.9, 81.4, 85.8, and 75.4% using qPCR, respectively. T-376 sporozoite invasion into MDBK cells was reduced to 48.9% by Mad. Study (3) was conducted to determine inhibition exerted by toltrazuril (Tol). Tol at 5 μg/ml reduced reproduction of Houghton strain by 95%, whereas T-376 was only reduced by 86.5%. The presented experiments indicate that infectivity inhibition of sporozoites incubated for 4 h with anticoccidials and development inhibition after 96 h of infection by qPCR are suitable means to assess sensitivity of E. tenella strains to anticoccidials.

Geno- and cytotoxicity of salinomycin in human nasal mucosa and peripheral blood lymphocytes

Salinomycin is usually applied in stock breading but has also been described as a promising agent against cancer stem cells (CSC). However, knowledge about the toxicity of this ionophor substance is incomplete. The aim of this study was to investigate cyto- and genotoxic effects of salinomycin in human non-malignant cells.Primary human nasal mucosa cells (monolayer and mini organ cultures) and peripheral blood lymphocytes from 10 individuals were used to study the cytotoxic effects of salinomycin (0.1–175μM) by annexin–propidiumiodide- and MTT-test. The comet assay was performed to evaluate DNA damage. Additionally, the secretion of interleukin-8 was analyzed by ELISA.Flow cytometry and MTT assay revealed significant cytotoxic effects in nasal mucosa cells and lymphocytes at low salinomycin concentrations of 10–20μM. No genotoxic effects could be observed. IL-8 secretion was elevated at 5μM.Salinomycin-induced cytotoxic and pro-inflammatory effects were seen at concentrations relevant for anti-cancer treatment. Concurrent to the evaluation of salinomycin application in experimental oncology, adverse effects in non-malignant cells need to be monitored and reduced as much as possible. Further studies are also warranted to evaluate the toxic effects in a variety of human cell systems, e.g., liver, kidney and muscle cells.

A rapid method for determining salinomycin and monensin sensitivity in Eimeria tenella

Standard methods of determining the ionophore sensitivity of Eimeria rely on infecting chickens with an isolate or a mixture of Eimeria spp. oocysts in the presence of different anti-coccidial drugs. The purpose of this study was to develop a rapid in vitro method for assessing salinomycin and monensin sensitivity in Eimeria tenella. Cultures of MDBK cells were grown to 85% confluency, and then inoculated with excysted E. tenella laboratory strain (APU-1) sporozoites in the presence of different concentrations of salinomycin or monensin. At various timepoints, the monolayers were fixed for counting intraceullar sporozoites, or were subjected to DNA extraction, followed by molecular analysis using quantitative (qPCR) or semi-quantitative PCR (sqPCR). Preliminary experiments showed that 24h was the optimum time for harvesting the E. tenella-infected cell cultures. The average number of E. tenella sporozoites relative to untreated controls displayed a linear decrease between 0.3 and 33.0μg/ml salinomycin and between 0.3 and 3.3μg/ml monensin. A similar pattern was observed in the relative amount of E. tenella DNA as measured by sqPCR. A linear decrease in the relative amount of E. tenella DNA was observed over the entire range of salinomycin and monensin concentrations as measured by qPCR possibly reflecting the greater sensitivity of this assay. Comparison of sporozoite counting, sqPCR, and qPCR signals using a criterion of 50% inhibition in sporozoite numbers or level of PCR amplification product showed good agreement between the three assays. E. tenella field isolates (FS-1 and FS-2) displaying resistance to salinomycin and monensin were evaluated in the in vitro assay using qPCR and sqPCR. Compared to E. tenella APU-1, the E. tenella FS-1 and FS-2 isolates showed higher levels of E. tenella DNA at 24h by both qPCR and sqPCR. This in vitro assay represents a significant advance in developing rapid, cost-effective methods for assessing ionophore sensitivity in E. tenella.