Oxysterols, oxidized derivatives of cholesterol, act in breast cancer (BC) as selective estrogen receptor modulators and affect cholesterol homeostasis, drug transport, nuclear and cell receptors, and other signaling proteins. Using data from three highly overlapping sets of patients (N = 162 in total) with early-stage estrogen-receptor-positive luminal BC-high-coverage targeted DNA sequencing (113 genes), mRNA sequencing, and full micro-RNA (miRNA) transcriptome microarrays-we describe complex oxysterol-related interaction (correlation) networks, with validation in public datasets (n = 538) and 11 databases. The ESR1-CH25H-INSIG1-ABCA9 axis was the most prominent, interconnected through miR-125b-5p, miR-99a-5p, miR-100-5p, miR-143-3p, miR-199b-5p, miR-376a-3p, and miR-376c-3p. Mutations in SC5D, CYP46A1, and its functionally linked gene set were associated with multiple differentially expressed oxysterol-related genes. STARD5 was upregulated in patients with positive lymph node status. High expression of hsa-miR-19b-3p was weakly associated with poor survival. This is the first study of oxysterol-related genes in BC that combines DNA, mRNA, and miRNA multiomics with detailed clinical data. Future studies should provide links between intratumoral oxysterol signaling depicted here, circulating oxysterol levels, and therapy outcomes, enabling eventual clinical exploitation of present findings.

• Klíčová slova
• breast cancer, integrative analysis, interaction network, multiomics, oxysterols, survival,
• MeSH
• lidé MeSH
• messenger RNA genetika   MeSH
• mikro RNA * genetika   metabolismus   MeSH
• nádory prsu * patologie   MeSH
• oxysteroly * MeSH
• transkriptom genetika   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• messenger RNA MeSH
• mikro RNA * MeSH
• oxysteroly * MeSH

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

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