Oxysterols play significant roles in many physiological and pathological processes including cancer. They modulate some of the cancer hallmarks pathways, influence the efficacy of anti-cancer drugs, and associate with patient survival. In this study, we aimed to analyze the role of 7-ketocholesterol (7-KC) in breast carcinoma cells and its potential modulation of the tamoxifen effect. 7-KC effects were studied in two estrogen receptor (ER)-positive (MCF-7 and T47D) and one ER-negative (BT-20) breast cancer cell lines. First, we tested the viability of cells in the presence of 7-KC. Next, we co-incubated cells with tamoxifen and sublethal concentrations of 7-KC. We also tested changes in caspase 3/7 activity, deregulation of the cell cycle, and changes in expression of selected genes/proteins in the presence of tamoxifen, 7-KC, or their combination. Finally, we analyzed the effect of 7-KC on cellular migration and invasion. We found that the presence of 7-KC slightly decreases the efficacy of tamoxifen in MCF-7 cells, while an increased effect of tamoxifen and higher caspase 3/7 activity was observed in the BT-20 cell line. In the T47D cell line, we did not find any modulation of tamoxifen efficacy by the presence of 7-KC. Expression analysis showed the deregulation in CYP1A1 and CYP1B1 with the opposite trend in MCF-7 and BT-20 cells. Moreover, 7-KC increased cellular migration and invasion potential regardless of the ER status. This study shows that 7-KC can modulate tamoxifen efficacy as well as cellular migration and invasion, making 7-KC a promising candidate for future studies.

• Klíčová slova
• 7-ketocholesterol, Breast cancer, Migration, Proliferation, Tamoxifen,
• MeSH
• chemorezistence MeSH
• hormonální protinádorové látky farmakologie   MeSH
• kaspasa 3 genetika   MeSH
• lidé MeSH
• MFC-7 buňky MeSH
• nádorové buněčné linie MeSH
• nádory prsu * farmakoterapie   MeSH
• proliferace buněk MeSH
• receptory pro estrogeny metabolismus   MeSH
• tamoxifen * farmakologie   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 7-ketocholesterol MeSH Prohlížeč
• hormonální protinádorové látky MeSH
• kaspasa 3 MeSH
• receptory pro estrogeny MeSH
• tamoxifen * MeSH

Oxygenated metabolites of cholesterol (oxysterols) have been previously demonstrated to contribute to progression of various cancers and to modulate resistance to breast cancer endocrine therapy in vitro. We measured prognostic roles of circulating levels of seven major oxysterols in the progression of luminal subtype breast carcinoma. Liquid chromatography coupled with tandem mass spectrometry was used for determination of levels of non-esterified 25-hydroxycholesterol, 27-hydroxycholesterol, 7α-hydroxycholesterol, 7-ketocholesterol, cholesterol-5α,6α-epoxide, cholesterol-5β,6β-epoxide, and cholestane-3β,5α,6β-triol in plasma samples collected from patients (n = 58) before surgical removal of tumors. Oxysterol levels were then associated with clinical data of patients. All oxysterols except cholesterol-5α,6α-epoxide were detected in patient plasma samples. Circulating levels of 7α-hydroxycholesterol and 27-hydroxycholesterol were significantly lower in patients with small tumors (pT1) and cholesterol-5β,6β-epoxide and cholestane-3β,5α,6β-triol were lower in patients with stage IA disease compared to larger tumors or more advanced stages. Patients with higher than median cholestane-3β,5α,6β-triol levels had significantly worse disease-free survival than patients with lower levels (p = 0.037 for all patients and p = 0.015 for subgroup treated only with tamoxifen). In conclusion, this study shows, for the first time, that circulating levels of oxysterols, especially cholestane-3β,5α,6β-triol, may have prognostic roles in patients with luminal subtype breast cancer.

• Klíčová slova
• Breast cancer, Cholestane-3β,5α,6β-triol, Cholesterol, Hydroxycholesterol, Oxysterol, Plasma, Prognosis,
• MeSH
• duktální karcinom prsu krev   patologie   MeSH
• invazivní růst nádoru MeSH
• lidé středního věku MeSH
• lidé MeSH
• míra přežití MeSH
• nádorové biomarkery analýza   MeSH
• nádory prsu krev   patologie   MeSH
• následné studie MeSH
• oxysteroly krev   MeSH
• prognóza MeSH
• receptor erbB-2 metabolismus   MeSH
• receptory pro estrogeny metabolismus   MeSH
• receptory progesteronu metabolismus   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• ERBB2 protein, human MeSH Prohlížeč
• nádorové biomarkery MeSH
• oxysteroly MeSH
• receptor erbB-2 MeSH
• receptory pro estrogeny MeSH
• receptory progesteronu MeSH

INTRODUCTION: Oxygenated metabolites of cholesterol (“oxysterols”) can influence carcinogenesis and contribute to resistance to endocrine therapy, an effect mostly described in vitro. OBJECTIVES: We sought to establish a method for screening plasma levels of oxysterols in breast cancer patients, estimate their individual variability and detection limits, and provide basic information about their roles in tumor biology. METHOD: Liquid-chromatography coupled with tandem mass spectrometry was used for determination of levels of 25-hydroxycholesterol, 27-hydroxycholesterol, 7α-hydroxycholesterol, and 7-ketocholesterol in plasma sample pairs from patients before and 12–24 months after surgical removal of tumors (n=24). Deuterated standards of all oxysterols were used for method validation. RESULT: All oxysterols were successfully detected in patient plasma samples. A significant increase in the level of 7-ketocholesterol was observed in the samples following tumor removal and the start of therapy compared to the sampling before (p=0.002). This increase was unrelated to personal characteristics of patients, expression of estrogen receptor, or to adjuvant therapy type. CONCLUSION: This study shows, for the first time, that circulating levels of oxysterols, especially 7-ketocholesterol, may reflect the presence of tumor cells in patients.

• Klíčová slova
• breast cancer, estrogen, oxysterols, plasma, therapy,
• MeSH
• cholesterol krev   metabolismus   MeSH
• lidé MeSH
• nádory prsu krev   chirurgie   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• dopisy MeSH
• Názvy látek
• cholesterol MeSH

The European Cooperation in Science and Technology (COST) provides an ideal framework to establish multi-disciplinary research networks. COST Action BM1203 (EU-ROS) represents a consortium of researchers from different disciplines who are dedicated to providing new insights and tools for better understanding redox biology and medicine and, in the long run, to finding new therapeutic strategies to target dysregulated redox processes in various diseases. This report highlights the major achievements of EU-ROS as well as research updates and new perspectives arising from its members. The EU-ROS consortium comprised more than 140 active members who worked together for four years on the topics briefly described below. The formation of reactive oxygen and nitrogen species (RONS) is an established hallmark of our aerobic environment and metabolism but RONS also act as messengers via redox regulation of essential cellular processes. The fact that many diseases have been found to be associated with oxidative stress established the theory of oxidative stress as a trigger of diseases that can be corrected by antioxidant therapy. However, while experimental studies support this thesis, clinical studies still generate controversial results, due to complex pathophysiology of oxidative stress in humans. For future improvement of antioxidant therapy and better understanding of redox-associated disease progression detailed knowledge on the sources and targets of RONS formation and discrimination of their detrimental or beneficial roles is required. In order to advance this important area of biology and medicine, highly synergistic approaches combining a variety of diverse and contrasting disciplines are needed.

• Klíčová slova
• Antioxidants, Oxidative stress, Reactive nitrogen species, Reactive oxygen species, Redox signaling, Redox therapeutics,
• MeSH
• Evropská unie MeSH
• lidé MeSH
• mezinárodní spolupráce * MeSH
• molekulární biologie organizace a řízení   trendy   MeSH
• oxidace-redukce MeSH
• reaktivní formy kyslíku chemie   metabolismus   MeSH
• signální transdukce MeSH
• společnosti vědecké MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• reaktivní formy kyslíku MeSH