Effects of tamoxifen on DNA adduct formation and arylamines N-acetyltransferase activity in human breast cancer cells. 2004

Jau-Hong Lee, and Hsu-Feng Lu, and Der-Yean Wang, and Dar-Ren Chen, and Chin-Cheng Su, and Yi-Shuan Chen, and Jen-Hung Yang, and Jing-Gung Chung
Department of Surgery, China Medical University Hospital, Taichung 404, Taiwan, ROC. jauhong@yahoo.com

Tamoxifen was used to determine the effects of N-acetyltransferase(NAT) activity and 2-aminofluorene (2-AF)-DNA adduct formation in human breast cancer cells. Breast cancer cells were categorized into two groups based on the status of estrogen receptor, ER (+) and ER (-). 2-AF-DNA adduct formations in breast cancer cells are 2.58 +/- 0.39 pmol adduct/mg DNA for ER (+) and 2.74 +/- 0.46 pmol adduct/mg DNA for ER (-), respectively. Co-treatment with 1 microM tamoxifen inhibited DNA-adduct formations up to 65% in ER (+) and 61% in ER (-), respectively. The inhibition of Tamoxifen on DNA adduct formation between ER (+) and ER (-) cell was not significantly different. The results of the N-acetyltransferase activity in human breast cancer cells were inhibited by tamoxifen in a dose dependent manner. Tamoxifen inhibited 50.0% and 42.8% of Km in ER (+) and ER (-), 58.2% and 35.6% of Vmax, respectively. Based on the kinetic study of N-acetyltransferase activity, tamoxifen plays a non-competitive role in the acetylation reaction. This study demonstrates that tamoxifen inhibited not only NAT activity but also DNA-adduct formation in human breast cancer cells, regardless of the status of estrogen receptor. These findings could provide a clue that tamoxifen has chemoprevention effects in breast cancer.

UI MeSH Term Description Entries
D007700 Kinetics The rate dynamics in chemical or physical systems.
D011960 Receptors, Estrogen Cytoplasmic proteins that bind estrogens and migrate to the nucleus where they regulate DNA transcription. Evaluation of the state of estrogen receptors in breast cancer patients has become clinically important. Estrogen Receptor,Estrogen Receptors,Estrogen Nuclear Receptor,Estrogen Receptor Type I,Estrogen Receptor Type II,Estrogen Receptors Type I,Estrogen Receptors Type II,Receptor, Estrogen Nuclear,Receptors, Estrogen, Type I,Receptors, Estrogen, Type II,Nuclear Receptor, Estrogen,Receptor, Estrogen
D001943 Breast Neoplasms Tumors or cancer of the human BREAST. Breast Cancer,Breast Tumors,Cancer of Breast,Breast Carcinoma,Cancer of the Breast,Human Mammary Carcinoma,Malignant Neoplasm of Breast,Malignant Tumor of Breast,Mammary Cancer,Mammary Carcinoma, Human,Mammary Neoplasm, Human,Mammary Neoplasms, Human,Neoplasms, Breast,Tumors, Breast,Breast Carcinomas,Breast Malignant Neoplasm,Breast Malignant Neoplasms,Breast Malignant Tumor,Breast Malignant Tumors,Breast Neoplasm,Breast Tumor,Cancer, Breast,Cancer, Mammary,Cancers, Mammary,Carcinoma, Breast,Carcinoma, Human Mammary,Carcinomas, Breast,Carcinomas, Human Mammary,Human Mammary Carcinomas,Human Mammary Neoplasm,Human Mammary Neoplasms,Mammary Cancers,Mammary Carcinomas, Human,Neoplasm, Breast,Neoplasm, Human Mammary,Neoplasms, Human Mammary,Tumor, Breast
D002273 Carcinogens Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included. Carcinogen,Oncogen,Oncogens,Tumor Initiator,Tumor Initiators,Tumor Promoter,Tumor Promoters,Initiator, Tumor,Initiators, Tumor,Promoter, Tumor,Promoters, Tumor
D004305 Dose-Response Relationship, Drug The relationship between the dose of an administered drug and the response of the organism to the drug. Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D005449 Fluorenes A family of diphenylenemethane derivatives.
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000107 Acetylation Formation of an acetyl derivative. (Stedman, 25th ed) Acetylations
D001191 Arylamine N-Acetyltransferase An enzyme that catalyzes the transfer of acetyl groups from ACETYL-COA to arylamines. It can also catalyze acetyl transfer between arylamines without COENZYME A and has a wide specificity for aromatic amines, including SEROTONIN. However, arylamine N-acetyltransferase should not be confused with the enzyme ARYLALKYLAMINE N-ACETYLTRANSFERASE which is also referred to as SEROTONIN ACETYLTRANSFERASE. Arylamine Acetylases,Arylamine Acetyltransferases,Acetyl-CoA Arylamine N-Acetyltransferase,Arylamine Acetylase,Acetyl CoA Arylamine N Acetyltransferase,Acetylase, Arylamine,Acetylases, Arylamine,Acetyltransferases, Arylamine,Arylamine N Acetyltransferase,Arylamine N-Acetyltransferase, Acetyl-CoA,N-Acetyltransferase, Acetyl-CoA Arylamine,N-Acetyltransferase, Arylamine
D013629 Tamoxifen One of the SELECTIVE ESTROGEN RECEPTOR MODULATORS with tissue-specific activities. Tamoxifen acts as an anti-estrogen (inhibiting agent) in the mammary tissue, but as an estrogen (stimulating agent) in cholesterol metabolism, bone density, and cell proliferation in the ENDOMETRIUM. ICI-46,474,ICI-46474,ICI-47699,Nolvadex,Novaldex,Soltamox,Tamoxifen Citrate,Tomaxithen,Zitazonium,Citrate, Tamoxifen,ICI 46,474,ICI 46474,ICI 47699,ICI46,474,ICI46474,ICI47699

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