Dysregulation of Catalase by a Sulphamoylated Estradiol Analogue Culminates in Antimitotic Activity and Cell Death Induction in Breast Cancer Cell Lines.

Recent findings revealed that 2-ethyl-17-oxoestra-1,3,5(10)-trien-3-yl sulfamate (ESE-one) induces antiproliferative activity and cell rounding dependent on the generation of superoxide anion, hydrogen peroxide and peroxyl radical. In the current study, the role of these reactive oxygen species was assessed in the activity exerted by ESE-one on cell cycle progression, mitochondrial membrane potential and cell death induction in breast tumorigenic cells. The influence of ESE-one was also investigated on superoxide dismutase and catalase activity. ESE-one induced a time-dependent accumulation of cells in the G1 phase and G2/M phase that is partially impaired by tiron and trolox and N,N'-dimethylthiourea suggesting that superoxide anion, hydrogen peroxide and peroxyl radical are required for these effects exerted by ESE-one. Flow cytometry data in MCF-7 cells demonstrated that tiron decreased depolarization of the membrane potential in ESE-one exposed cells, indicating that superoxide anion plays a role in the depolarization effects induced by ESE-one. Spectrophotometry data showed that ESE-one decreased catalase activity in both cell lines. This study contributes towards pertinent information regarding the effects of an in silico-designed sulfamoylated compound on antioxidant enzymes leading to aberrant quantities of specific reactive oxygen species resulting in antimitotic activity culminating in the induction of cell death in breast cancer cell lines.

Sulphamoylated Estradiol Analogue Induces Reactive Oxygen Species Generation to Exert Its Antiproliferative Activity in Breast Cancer Cell Lines.

2-Methoxyestradiol (2ME), a 17ß-estradiol metabolite, exerts anticancer properties in vitro and in vivo. To address 2ME's low bioavailability, research led to the in silico design of sulphamoylated 2ME analogues. However, the role of oxidative stress induced in the activity exerted by sulphamoylated compounds remains elusive. In the current study, the influence of 2-Ethyl-17-oxoestra-1,3,5(10)-trien-3-yl sulphamate (ESE-one) on reactive oxygen species (ROS) induction and its effect on cell proliferation, as well as morphology, were assessed in breast tumorigenic cells (MCF-7 and MDA-MB-231). Fluorescent microscopy showed that sulphamoylated estradiol analogues induced hydrogen peroxide and superoxide anion, correlating with decreased cell growth demonstrated by spectrophotometry data. ESE-one exposure resulted in antiproliferation which was repressed by tiron (superoxide inhibitor), trolox (peroxyl inhibitor) and N,N'-dimethylthiourea (DMTU) (hydrogen peroxide inhibitor). Morphological studies demonstrated that tiron, trolox and DMTU significantly decreased the number of rounded cells and shrunken cells in MCF-7 and MDA-MB-231 cells induced by ESE-one. This in vitro study suggests that ESE-one induces growth inhibition and cell rounding by production of superoxide anion, peroxyl radical and hydrogen peroxide. Identification of these biological changes in cancer cells caused by sulphamoylated compounds hugely contributes towards improvement of anticancer strategies and the ROS-dependent cell death pathways in tumorigenic breast cells.

Warburg effect and its role in tumourigenesis.

Glucose is a crucial molecule in energy production and produces different end products in non-tumourigenic- and tumourigenic tissue metabolism. Tumourigenic cells oxidise glucose by fermentation and generate lactate and adenosine triphosphate even in the presence of oxygen (Warburg effect). The Na+/H+-antiporter is upregulated in tumourigenic cells resulting in release of lactate- and H+ ions into the extracellular space. Accumulation of lactate- and proton ions in the extracellular space results in an acidic environment that promotes invasion and metastasis. Otto Warburg reported that tumourigenic cells have defective mitochondria that produce less energy. However, decades later it became evident that these mitochondria have adapted with alterations in mitochondrial content, structure, function and activity. Mitochondrial biogenesis and mitophagy regulate the formation of new mitochondria and degradation of defective mitochondria in order to combat accumulation of mutagenic mitochondrial deoxyribonucleic acid. Tumourigenic cells also produce increase reactive oxygen species (ROS) resulting from upregulated glycolysis leading to pathogenesis including cancer. Moderate ROS levels exert proliferative- and prosurvival signaling, while high ROS quantities induce cell death. Understanding the crosstalk between aberrant metabolism, redox regulation, mitochondrial adaptions and pH regulation provides scientific- and medical communities with new opportunities to explore cancer therapies.

Comparison of structures and cytotoxicity of mupirocin and batumin against melanoma and several other cancer cell lines.

Aim: To determine the computer-predicted anticancer activity of mupirocin and to compare its activities with those determined for another polyene antibiotic, batumin. Materials & methods: Molecular docking, cytotoxicity assays, cell microscopy and cell cycle progression were studied in cancer and nontumorigenic cell lines. Results & conclusion: Cytotoxicity of mupirocin against several cancerous cell lines was detected with the highest one (IC50 = 5.4 µg/ml) against melanoma cell line. The profile of cytotoxicity of mupirocin was similar to that reported for batumin. Nevertheless, the morphology of cells treated with these antibiotics and alterations in cell cycle progression suggested possible dissimilarity in their mechanisms of action. Selective cytotoxicity of mupirocin against melanoma cells potentiates further studies to discover nontoxic drugs for melanoma prevention.

Promising anticancer activity of batumin: a natural polyene antibiotic produced by Pseudomonas batumici.

AIM: To determine the computer-predicted anticancer activity of antibiotic batumin. MATERIALS & METHODS: Cytotoxicity assays, cell morphology microscopy and cell cycle progression were studied in cancer and nontumorigenic cell lines. An in vivo experiment on Lewis lung carcinoma (3LL)-transplanted mice was conducted to evaluate potential antimetastatic. RESULTS & CONCLUSION: Cytotoxicity against melanoma and lung carcinoma cells (IC50 ≈ 5 µg/ml) was detected. Hypercondensed chromatin and apoptotic body formation in batumin-treated cells suggested the induction of apoptosis supported also by an observed increase in the quantity of cells occupying the sub-G1 cell cycle phase. Twofold reduction in the number and volume of lung metastases in Lewis lung carcinoma (3LL)-bearing batumin-treated mice was demonstrated. Highly specific cytotoxicity of batumin against cancer cell lines potentiates further studies.