Effect of Tumour Necrosis Factor-Alpha on Estrogen Metabolic Pathways in Breast Cancer Cells

Abstract

Tumor necrosis factor-alpha (TNF-α) is a proinflammatory cytokine that has been linked to breast cancer development. Estrogen metabolic pathway is also involved in breast carcinogenesis and DNA adducts formation. In this study we investigated the effect of TNF-α on the estrogen metabolic pathway in MCF-7, a breast cancer cell line. Capillary liquid chromatography/mass spectrometry (LC/MS) and High performance liquid chromatography (HPLC) were used for analysis of estrogen metabolites and estrogen-DNA adducts levels respectively. Reporter gene assay, Real time reverse transcription polymerase chain reaction (real time RT-PCR) and Western blot were used to assess the expression of estrogen metabolizing genes and enzymes. TNF-α significantly increased the total EM and decreased the estrone (E1) / 17-β estradiol (E2) ratio. Moreover, it altered the expression of genes and enzymes involved in E2 activation and deactivation pathways e.g. Cytochrome P-450 1A1 (CYP1A1), Cytochrome P-450 1B1 (CYP1B1), Catechol-O-methyl transferase (COMT) and Nicotinamide adenine dinucleotide phosphate-quinone oxidoreductase 1 (NQO1). In addition, there were increased levels of some catechol estrogens e.g. 4-hydroxy-estrone (4-OHE1) and 2-hydroxyestradiol (2-OHE2) with decreased levels of methylated catechols e.g. 2-methoxy estradiol (2-MeOE2). DNA adducts especially 4-OHE1-[2]-1-N3 Adenine was significantly increased. TNF-α directs the estrogen metabolism into more hormonally active and carcinogenic products in MCF-7. This may implicate a new possible explanation for inflammation associated breast cancer.

Associations of the Fecal Microbiome With Urinary Estrogens and Estrogen Metabolites in Postmenopausal Women

“…Chronic exposure to lipopolysaccharide and other toxins shed by bacteria induces inflammation by activation of toll-like receptors in adipocytes, in turn releasing proinflammatory cytokines (35). In vitro exposure of breast epithelial cells to the proinflammatory cytokine TNF-␣ leads to increased total EM, 2-and 4-pathway metabolites, and the ratio of estradiol to estrone (36). Functional effects on estrogen-metabolizing enzymes induced by TNF-␣ include an increased expression of aromatase (CYP19), CYP1A1, and CYP1B1; reduced expression of catechol O-methyltransferase and nitroquinoxaline-01; and modulated expression of 17␤-hydroxysteroid dehydrogenase type I (36,37).…”

“…In vitro exposure of breast epithelial cells to the proinflammatory cytokine TNF-␣ leads to increased total EM, 2-and 4-pathway metabolites, and the ratio of estradiol to estrone (36). Functional effects on estrogen-metabolizing enzymes induced by TNF-␣ include an increased expression of aromatase (CYP19), CYP1A1, and CYP1B1; reduced expression of catechol O-methyltransferase and nitroquinoxaline-01; and modulated expression of 17␤-hydroxysteroid dehydrogenase type I (36,37). Other in vivo studies have demonstrated that inflammation can drive estrogen production in the breast through the up-regulation of aromatase (38).…”

Low doses of paclitaxel enhance liver metastasis of breast cancer cells in the mouse model

“…One-way ANOVA was used for all the quantifications: *P < 0.05, **P < 0.01. to 4-hydroxyestrogens, CYP1B1 is responsible for the activation of the invasive potential in human endometrial carcinomas [49]. Additionally, low-dose PTX also significantly and negatively influenced the expression of COMT, the major detoxifying enzyme for 4-hydroxyestrogens [39]. Collectively, we hypothesized that low-dose PTX can induce the dysregulated expression of estrogen metabolic enzymes and might provide a tumor-promoting microenvironment that facilitates the formation of metastases in liver.…”

“…7C). To the contrary, catechol-O-methyltransferase (COMT), the enzyme responsible for the detoxification of 4-OHE2 into methoxy derivatives [39], was obviously reduced in PTX-treated liver samples (Fig. 7D,E).…”

Leptin influences estrogen metabolism and increases DNA adduct formation in breast cancer cells

“…Consequently, research on compounds that affect the estrogen metabolic pathway is ongoing. Example of these compounds are the dietary supplements resveratrol and N-acetylcysteine 8 and the tumor necrosis factor-alpha (TNF-α) 9 , as well as vegetable and carbohydrate consumption 10 . …”