TNF-alpha increases the local estrogen biosynthesis in human endometrial glandular cells and directs estrogen metabolism into more hormonally active and carcinogenic metabolites. These effects may impact many physiological and pathological processes that occur within the endometrium.
Prolonged exposure to unopposed estrogens is a major risk factor for the development of endometrial cancer. Oxidative metabolism of estradiol (E 2 ) into the catecholestrogens (CEs), 4-hydroxyestradiol (4-OHE 2 ) and 2-hydroxyestradiol (2-OHE 2 ), may play an important role in estrogen carcinogenicity. CEs can be oxidized to the corresponding ortho-quinone derivatives with concomitant formation of the reactive oxygen species (ROS). Catechol-O-methyltransferase (COMT) is the major enzyme involved in the detoxification of CEs in extrahepatic tissues. We investigated the potential of E 2 , 2-OHE 2 and 4-OHE 2 to induce microsatellite instability (MSI) and neoplastic transformation of immortalized human endometrial glandular (EM) cells. We also investigated the functional significance of COMT gene expression on modulating the effects of E 2 and CEs in EM cells. Our data indicated that E 2 and 4-OHE 2 induce MSI, ROS and neoplastic transformation in EM cells. The capacity of E 2 and its catechol metabolites to induce MSI, ROS and neoplastic transformation in EM cells is ranked as follows: 4-OHE 2 > E 2 > 2-OHE 2 . Knockdown of COMT expression in EM cells resulted in increased estrogenic milieu and increased estrogen-induced cell proliferation. More importantly, knockdown of COMT increased the propensity of E 2 or CEs to induce ROS, MSI and neoplastic transformation of EM cells. In contrast, overexpression of COMT in EM cells significantly reduced the cellular estrogenic milieu and protected against E 2 -or CEs-induced, ROS, MSI and neoplastic transformation. The capacity of E 2 or CEs to induce neoplastic transformation of human endometrial glandular cells in vitro may suggest that E 2 -induced endometrial cancer is mediated by its metabolism into CEs. Our study clearly indicates that COMT gene expression plays a critical role in modulating the hormonal and carcinogenic effects of E 2 and CEs and, consequently, modifies the risk for E 2 -induced endometrial cancer. To the best of our knowledge, this is the first study to (i) demonstrate the potential capacity of estrogen and its catechol metabolites to induce neoplastic transformation of immortalized human endometrial glandular cells; and (ii) illustrate the important role of COMT gene expression in protecting against E 2 -induced endometrial cancer. ' 2008 Wiley-Liss, Inc.
Key words: catecholestrogens;COMT; genomic instability; endometrial cancer Endometrial cancer is the most common cancer of the genital tract in American women and ranks first in incidence and second in mortality among gynecological malignancies. 1 It is estimated that the rates of endometrial cancer in American women are among the highest in the world. 2 The risk factors for endometrial cancer include nulliparity, early age at menarche, late age at menopause, obesity and long-term use of estrogen replacement therapy (ERT). These risk factors seem to relate, either directly or indirectly, prolonged exposure to an unopposed estrogen. 3 Most endometrial carcinomas are Type I estrogen-associated endo...
Uterine leiomyomas (LM) affect a high percentage of reproductive-age women. They develop as discrete, well-defined tumors that are easily accessible with imaging techniques – making this disease ideal for localized gene therapy approaches. In this study, we determined the efficacy of adenovirus-mediated herpes simplex virus thymidine kinase gene transfer in combination with ganciclovir (Ad-TK/GCV) as a potential therapy for LM. Rat ELT-3 LM cells and human LM cells were transfected with different multiplicity of infections (10–100 plaque forming units [PFU]/cell) of Ad-TK and treated with GCV (5, 10, or 20 µg/ml) for 5 days. To test the bystander effect, Ad-TK-transfected ELT-3 cells (100 PFU/cell) or LM cells (10 PFU/cell) were cocultured with corresponding nontransfected cells at increasing percentages and treated with GCV followed by cell counting. In ELT-3 cells transfected with Ad-TK/GCV (10, 20, 50, or 100 PFU/cell), the cell count was reduced by 24, 42, 77, and 87%, respectively, compared with the control cells (transfected with Ad-Lac Z/GCV). Similarly, in LM cells transfected with Ad-TK/GCV (10, 50, or 100 PFU/cell), the cell count was reduced by 31, 62, and 82%, respectively, compared with the control. A strong bystander effect was noted in both ELT-3 and LM cells with significant killing (p = 0.001) at a ratio of infected:uninfected cells of only 1:99 and maximal killing at 1:4. This study demonstrates the potential efficacy of the Ad-TK/GCV gene therapy approach as a viable nonsurgical alternative treatment for uterine LM.
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.
ContextDevelopment of optimal medicinal treatments of uterine leiomyomas represents a significant challenge. 2-Methoxyestradiol (2ME) is an endogenous estrogen metabolite formed by sequential action of CYP450s and catechol-O-methyltransferase (COMT). Our previous study demonstrated that 2ME is a potent antiproliferative, proapoptotic, antiangiogenic, and collagen synthesis inhibitor in human leiomyomas cells (huLM).ObjectivesOur objectives were to investigate whether COMT expression, by the virtue of 2ME formation, affects the growth of huLM, and to explore the cellular and molecular mechanisms whereby COMT expression or treatment with 2ME affect these cells.ResultsOur data demonstrated that E2-induced proliferation was less pronounced in cells over-expressing COMT or treated with 2ME (500 nM). This effect on cell proliferation was associated with microtubules stabilization and diminution of estrogen receptor α (ERα) and progesterone receptor (PR) transcriptional activities, due to shifts in their subcellular localization and sequestration in the cytoplasm. In addition, COMT over expression or treatment with 2ME reduced the expression of hypoxia-inducible factor -1α (HIF-1 α) and the basal level as well as TNF-α-induced aromatase (CYP19) expression.ConclusionsCOMT over expression or treatment with 2ME stabilize microtubules, ameliorates E2-induced proliferation, inhibits ERα and PR signaling, and reduces HIF-1 α and CYP19 expression in human uterine leiomyoma cells. Thus, microtubules are a candidate target for treatment of uterine leiomyomas. In addition, the naturally occurring microtubule-targeting agent 2ME represents a potential new therapeutic for uterine leiomyomas.
A. Shouman (2020) Design, synthesis and biological evaluation of a new thieno[2,3-d]pyrimidine-based urea derivative with potential antitumor activity against tamoxifen sensitive and resistant breast cancer cell lines,
We show for the first time that E2-induced hESC proliferation is associated with a shift in glucose metabolism toward aerobic glycolysis, and the molecular basis for this metabolic shift is linked to the effects of E2 on PKM2. In addition, PKM2 acts as a transcriptional coactivator for ERα and small-molecule PKM2 activators inhibit ERα transcriptional activity and reduce E2-induced cell proliferation.
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