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
• antitumorózní látky hormonální farmakologie   MeSH
• chemorezistence 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
• antitumorózní látky hormonální MeSH
• kaspasa 3 MeSH
• receptory pro estrogeny MeSH
• tamoxifen * 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

Oxysterols are oxygenated derivatives of cholesterol formed in the human body or ingested in the diet. By modulating the activity of many proteins [e.g., liver X receptors (LXRs), oxysterol-binding proteins (OSBPs), some ATP-binding cassette (ABC) transporters], oxysterols can affect many cellular functions and influence various physiological processes (e.g., cholesterol metabolism, membrane fluidity regulation, intracellular signaling pathways). Therefore, the role of oxysterols is also important in pathological conditions (e.g., atherosclerosis, diabetes mellitus type 2, neurodegenerative disorders). Finally, current evidence suggests that oxysterols play a role in malignancies such as breast, prostate, colon, and bile duct cancer. This review summarizes the physiological importance of oxysterols in the human body with a special emphasis on their roles in various tumors.

• Klíčová slova
• cancer, cholesterol, disease, oxysterols,
• MeSH
• cholesterol metabolismus   MeSH
• hydroxycholesteroly farmakologie   MeSH
• lidé MeSH
• metabolické sítě a dráhy účinky léků   MeSH
• metabolismus lipidů účinky léků   MeSH
• nádory etiologie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• cholesterol MeSH
• hydroxycholesteroly MeSH