Latest Publications

@article{vazquez-gomez_aryl_2023,

title = {Aryl hydrocarbon receptor (AhR) and pregnane X receptor (PXR) play both distinct and common roles in the regulation of colon homeostasis and intestinal carcinogenesis.},

author = {Gerardo Vázquez-Gómez and Jiří Petráš and Zdeněk Dvořák and Jan Vondráček},

doi = {10.1016/j.bcp.2023.115797},

issn = {1873-2968 0006-2952},

year  = {2023},

date = {2023-10-01},

journal = {Biochemical pharmacology},

volume = {216},

pages = {115797},

abstract = {Both aryl hydrocarbon receptor (AhR) and pregnane X receptor (PXR) belong among key regulators of xenobiotic metabolism in the intestinal tissue. AhR in particular is activated by a wide range of environmental and dietary carcinogens. The data accumulated over the last two decades suggest that both of these transcriptional regulators play a much wider role in the maintenance of gut homeostasis, and that both transcription factors may affect processes linked with intestinal tumorigenesis. Intestinal epithelium is continuously exposed to a wide range of AhR, PXR and dual AhR/PXR ligands formed by intestinal microbiota or originating from diet. Current evidence suggests that specific ligands of both AhR and PXR can protect intestinal epithelium against inflammation and assist in the maintenance of epithelial barrier integrity. AhR, and to a lesser extent also PXR, have been shown to play a protective role against inflammation-induced colon cancer, or, in mouse models employing overactivation of Wnt/β-catenin signaling. In contrast, other evidence suggests that both receptors may contribute to modulation of transformed colon cell behavior, with a potential to promote cancer progression and/or chemoresistance. The review focuses on both overlapping and separate roles of the two receptors in these processes, and on possible implications of their activity within the context of intestinal tissue.},

note = {Place: England},

keywords = {*Receptors, Animals, Aryl hydrocarbon receptor, Aryl Hydrocarbon/genetics/metabolism, Carcinogenesis/genetics/metabolism, Colon cancer, Colon/metabolism, Dietary contaminants, Epithelial barrier, Inflammation, Inflammation/metabolism, Intestine, Mice, Microbial agonists, Pregnane X receptor, Pregnane X Receptor/metabolism, Steroid/metabolism},

pubstate = {published},

tppubtype = {article}

}

@article{tylichova_n-3_2019,

title = {n-3 Polyunsaturated fatty acids alter benzo[a]pyrene metabolism and genotoxicity in human colon epithelial cell models.},

author = {Zuzana Tylichová and Jiří Neča and Jan Topinka and Alena Milcová and Jiřina Hofmanová and Alois Kozubík and Miroslav Machala and Jan Vondráček},

doi = {10.1016/j.fct.2018.12.021},

issn = {1873-6351 0278-6915},

year  = {2019},

date = {2019-02-01},

journal = {Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association},

volume = {124},

pages = {374–384},

abstract = {Dietary carcinogens, such as benzo[a]pyrene (BaP), are suspected to contribute to colorectal cancer development. n-3 Polyunsaturated fatty acids (PUFAs) decrease colorectal cancer risk in individuals consuming diets rich in PUFAs. Here, we investigated the impact of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid on metabolism and genotoxicity of BaP in human cell models derived from the colon: HT-29 and HCT-116 cell lines. Both PUFAs reduced levels of excreted BaP metabolites, in particular BaP-tetrols and hydroxylated BaP metabolites, as well as formation of DNA adducts in HT-29 and HCT-116 cells. However, EPA appeared to be a more potent inhibitor of formation of some intracellular BaP metabolites, including BaP-7,8-dihydrodiol. EPA also reduced phosphorylation of histone H2AX (Ser139) in HT-29 cells, which indicated that it may reduce further forms of DNA damage, including DNA double strand breaks. Both PUFAs inhibited induction of CYP1 activity in colon cells determined as 7-ethoxyresorufin-O-deethylase (EROD); this was at least partly linked with inhibition of induction of CYP1A1, 1A2 and 1B1 mRNAs. The downregulation and/or inhibition of CYP1 enzymes by PUFAs could thus alter metabolism and reduce genotoxicity of BaP in human colon cells, which might contribute to known chemopreventive effects of PUFAs in colon epithelium.},

note = {Place: England},

keywords = {Anticarcinogenic Agents/*pharmacology, Benzo(a)pyrene/adverse effects/*metabolism, Cell Line, Colon cancer, Cytochrome P450 Family 1/metabolism, DNA Adducts/metabolism, DNA Damage, DNA Damage/drug effects, Docosahexaenoic acid, Docosahexaenoic Acids/*pharmacology, Eicosapentaenoic acid, Eicosapentaenoic Acid/*pharmacology, Epithelial Cells/*drug effects, Histones/metabolism, Humans, Mutagens/adverse effects/*metabolism, Polycyclic aromatic hydrocarbon, S Phase Cell Cycle Checkpoints/drug effects, Tumor},

pubstate = {published},

tppubtype = {article}

}

@article{tylichova_butyrate_2018,

title = {Butyrate and docosahexaenoic acid interact in alterations of specific lipid classes in differentiating colon cancer cells.},

author = {Zuzana Tylichová and Josef Slavík and Miroslav Ciganek and Petra Ovesná and Pavel Krčmář and Nicol Straková and Miroslav Machala and Alois Kozubík and Jiřina Hofmanová and Jan Vondráček},

doi = {10.1002/jcb.26641},

issn = {1097-4644 0730-2312},

year  = {2018},

date = {2018-06-01},

journal = {Journal of cellular biochemistry},

volume = {119},

number = {6},

pages = {4664–4679},

abstract = {Docosahexaenoic acid (DHA) and sodium butyrate (NaBt) exhibit a number of interactive effects on colon cancer cell growth, differentiation, or apoptosis; however, the molecular mechanisms responsible for these interactions and their impact on cellular lipidome are still not fully clear. Here, we show that both dietary agents together induce dynamic alterations of lipid metabolism, specific cellular lipid classes, and fatty acid composition. In HT-29 cell line, a model of differentiating colon carcinoma cells, NaBt supported incorporation of free DHA into non-polar lipids and their accumulation in cytoplasmic lipid droplets. DHA itself was not incorporated into sphingolipids; however, it significantly altered representation of individual ceramide (Cer) classes, in particular in combination with NaBt (DHA/NaBt). We observed altered expression of enzymes involved in Cer metabolism in cells treated with NaBt or DHA/NaBt, and exogenous Cer 16:0 was found to promote induction of apoptosis in differentiating HT-29 cells. NaBt, together with DHA, increased n-3 fatty acid synthesis and attenuated metabolism of monounsaturated fatty acids. Finally, DHA and/or NaBt altered expression of proteins involved in synthesis of fatty acids, including elongase 5, stearoyl CoA desaturase 1, or fatty acid synthase, with NaBt increasing expression of caveolin-1 and CD36 transporter, which may further promote DHA incorporation and its impact on cellular lipidome. In conclusion, our results indicate that interactions of DHA and NaBt exert complex changes in cellular lipidome, which may contribute to the alterations of colon cancer cell differentiation/apoptotic responses. The present data extend our knowledge about the nature of interactive effects of dietary fatty acids.},

note = {Place: United States},

keywords = {Apoptosis/*drug effects, Butyrate, Butyrates/*pharmacology, Cell Differentiation/*drug effects, Ceramides, Colon cancer, Colonic Neoplasms/*metabolism/pathology, Docosahexaenoic acid, Docosahexaenoic Acids/*pharmacology, HCT116 Cells, Humans, lipid analyses, Lipid Metabolism/*drug effects, Membrane Lipids/classification/*metabolism, Phospholipids},

pubstate = {published},

tppubtype = {article}

}

@article{hofmanova_dietary_2017,

title = {Dietary fatty acids specifically modulate phospholipid pattern in colon cells with distinct differentiation capacities.},

author = {Jiřina Hofmanová and Josef Slavík and Petra Ovesná and Zuzana Tylichová and Jan Vondráček and Nicol Straková and Alena Hyršlová Vaculová and Miroslav Ciganek and Alois Kozubík and Lucie Knopfová and Jan Šmarda and Miroslav Machala},

doi = {10.1007/s00394-016-1196-y},

issn = {1436-6215 1436-6207},

year  = {2017},

date = {2017-06-01},

journal = {European journal of nutrition},

volume = {56},

number = {4},

pages = {1493–1508},

abstract = {PURPOSE: Although beneficial effects of the dietary n-3 docosahexaenoic acid (DHA) or butyrate in colon carcinogenesis have been implicated, the mechanisms of their action are not fully clear. Here, we investigated modulations of composition of individual phospholipid (PL) classes, with a particular emphasis on cardiolipins (CLs), in colon cells treated with DHA, sodium butyrate (NaBt), or their combination (DHA/NaBt), and we evaluated possible associations between lipid changes and cell fate after fatty acid treatment. METHODS: In two distinct human colon cell models, foetal colon (FHC) and adenocarcinoma (HCT-116) cells, we compared patterns and composition of individual PL classes following the fatty acid treatment by HPLC-MS/MS. In parallel, we measured the parameters reflecting cell proliferation, differentiation and death. RESULTS: In FHC cells, NaBt induced primarily differentiation, while co-treatment with DHA shifted their response towards cell death. In contrast, NaBt induced apoptosis in HCT-116 cells, which was not further affected by DHA. DHA was incorporated in all main PL types, increasing their unsaturation, while NaBt did not additionally modulate these effects in either cell model. Nevertheless, we identified an unusually wide range of CL species to be highly increased by NaBt and particularly by DHA/NaBt, and these effects were more pronounced in HCT-116 cells. DHA and DHA/NaBt enhanced levels of high molecular weight and more unsaturated CL species, containing DHA, which was specific for either differentiation or apoptotic responses. CONCLUSIONS: We identified a wide range of CL species in the colon cells which composition was significantly modified after DHA and NaBt treatment. These specific CL modulations might contribute to distinct cellular differentiation or apoptotic responses.},

note = {Place: Germany},

keywords = {Apoptosis, Apoptosis/drug effects, Butyrate, Butyric Acid/pharmacology, Cardiolipins, Caspase 3/genetics/metabolism, Cell Differentiation/*drug effects, Cell Line, Cell Proliferation/drug effects, Colon cancer, Colon/cytology/*drug effects, Docosahexaenoic acid, Docosahexaenoic Acids/*pharmacology, HCT116 Cells, Humans, Phospholipids, Phospholipids/*chemistry, Tandem Mass Spectrometry, Tumor},

pubstate = {published},

tppubtype = {article}

}

@article{tylichova_activation_2017,

title = {Activation of autophagy and PPARγ protect colon cancer cells against apoptosis induced by interactive effects of butyrate and DHA in a cell type-dependent manner: The role of cell differentiation.},

author = {Zuzana Tylichová and Nicol Straková and Jan Vondráček and Alena Hyršlová Vaculová and Alois Kozubík and Jiřina Hofmanová},

doi = {10.1016/j.jnutbio.2016.09.006},

issn = {1873-4847 0955-2863},

year  = {2017},

date = {2017-01-01},

journal = {The Journal of nutritional biochemistry},

volume = {39},

pages = {145–155},

abstract = {The short-chain and n-3 polyunsaturated fatty acids exhibit anticancer properties, and they may mutually interact within the colon. However, the molecular mechanisms of their action in colon cancer cells are still not fully understood. Our study focused on the mechanisms responsible for the diverse effects of sodium butyrate (NaBt), in particular when interacting with docosahexaenoic acid (DHA), in distinct colon cancer cell types, in which NaBt either induces cell differentiation or activates programmed cell death involving mitochondrial pathway. NaBt activated autophagy both in HT-29 cells, which are sensitive to induction of differentiation, and in nondifferentiating HCT-116 cells. However, autophagy supported cell survival only in HT-29 cells. Combination of NaBt with DHA-promoted cell death, especially in HCT-116 cells and after longer time intervals. The inhibition of autophagy both attenuated differentiation and enhanced apoptosis in HT-29 cells treated with NaBt and DHA, but it had no effect in HCT-116 cells. NaBt, especially in combination with DHA, activated PPARγ in both cell types. PPARγ silencing decreased differentiation and increased apoptosis only in HT-29 cells, therefore we verified the role of caspases in apoptosis, differentiation and also PPARγ activity using a pan-caspase inhibitor. In summary, our data suggest that diverse responses of colon cancer cells to fatty acids may rely on their sensitivity to differentiation, which may in turn depend on distinct engagement of autophagy, caspases and PPARγ. These results contribute to understanding of mechanisms underlying differential effects of NaBt, when interacting with other dietary fatty acids, in colon cancer cells.},

note = {Place: United States},

keywords = {Antineoplastic Agents/pharmacology, Apoptosis/*drug effects, Autophagy, Autophagy/*drug effects, Butyrate, Butyrates/*pharmacology, Butyric Acid/pharmacology, Caspase 3/genetics/metabolism, Cell Differentiation/drug effects, Colon cancer, Colonic Neoplasms/*pathology, Differentiation, Docosahexaenoic acid, Docosahexaenoic Acids/*pharmacology, HCT116 Cells, HT29 Cells, Humans, Mitochondria/drug effects/metabolism, PPAR gamma/genetics/*metabolism, PPARγ},

pubstate = {published},

tppubtype = {article}

}