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Evaluation of Effects of Quercetin (3, 3', 4', 5, 7-pentohidroxyflavon) on Apoptosis and Telomerase Enzyme Activity in MCF-7 and NIH-3T3 Cell Lines Compared with Tamoxifen

Year 2011, Volume: 2011 Issue: 3, 293 - 299, 01.03.2011
https://doi.org/10.5174/tutfd.2010.03372.3

Abstract

Objective: Quercetin has been shown to inhibit the proliferation of cancer cells. Tamoxifen is used for breast cancer. In this study, we have aimed to investigate the effects of quercetin and tamoxifen on telomerase enzyme activity and apoptosis in two cell lines. Methods: In this study, 10, 50 and 100 μM of quercetin and tamoxifen were used to treat MCF-7 and NIH-3T3. Apoptosis was determined by the TUNEL method (Terminal Deoxynucleotide Transferase dUTP Nick End Label) and telomerase enzyme activity was determined by ELISA (Enzyme-Linked Immunosorbent Assay). Results: In the NIH3T3 cell line, only 100 μM quercetin and tamoxifen induced significant apoptosis. In the MCF-7 cell line 10 μM and 100 μM quercetin in the 24th hour and 100 μM quercetin in the 72 hour induce apoptosis. In 24th and 48th hours, 50 μM tamoxifen and 100 μM tamoxifen in the 24th and 48th hours induce apoptosis in the MCF-7 cell line. In MCF-7 and NIH-3T3 cell lines, all doses of quercetin and tamoxifen reduced telomerase enzyme activity compared to the control group. Conclusion: In this study, it was shown that quercetin has similar effects to tamoxifen. However quercetin induces apoptosis more than decreasing telomerase enzyme activities, being different from tamoxifen. We hope that the findings will assist in developing new therapeutic pathways for preventing breast cancer. However, there should be many more studies in order to discover quercetin and other potential drugs.

References

  • Bentrem DJ, Gaiha P, Jordan VC. Oestrogens, Oestrogen Recep- tors and Breast Cancer. EJC 2003;1:1-12. [CrossRef]
  • Imyanitov EN, Hanson KP. Mechanism of Breast Cancer. Drug dis- covery today: disease mechanism 2004;1:235-45. [CrossRef]
  • Parton M, Dowsett M, Smith L. Studies of Apoptosis in Breast Cancer. BMJ 2001;322:1528-32. [CrossRef]
  • Lowe SW, Lin AW. Apoptosis in Cancer. Carcinogenesis 2000;21:485-95. [CrossRef]
  • Gilley D, Tanaka H, Herbert BS. Telomere Dysfunciton in Aging and Cancer. Int J Biochem Cell Biol 2005;37:1000-13. [CrossRef]
  • Falchetti A, Becherini L, Martineti V, Morelli A, Benvenuti S, Picar- iello L, et al. Telomerase Repeat Amplification Protocol (TRAP): A New Molecular Marker for Parathyroid Carcinoma. Biochem Biophys Res Commun 1999;265:252-5. [CrossRef]
  • Başaran A. Hücresel Yaşlanma ve Hücre Ölümsüzlüğünde Telom- eraz Enzim Kompleksi. Sendrom 2002;14:90-5.
  • Conquer JA, Maiani G, Azzini E, Raguzzini A, Holub BJ. Supple- mentation with Quercetin Markedly Increases Plasma Quercetin Concentration without Effect on Selected Risk Factors for Heart Disease in Healthy Subjects. J Nutr 1998;128:593-7.
  • Adebamowo CA, Cho E, Sampson L, Katan MB, Spiegelman D, Willett WC et al. Dietary Flavonos and Flavonol-Rich Foods In- take and Risk of Breast Cancer. International Journal of Cancer 2005;114:628-33. [CrossRef]
  • Kuo PC, Liu HF, Chao JI. Survivin and p53 modulate quercetin-in- duced cell growthinhibition and apoptosis in human lung carcino- ma cells. The Journal of Biological Chemistry 2004;279:55875-85. [CrossRef]
  • Huynh H, Nguyen TTT, Chan E, Tran E. Inhibition of ErbB2 and ErbB-3 Expression by Quercetin Prevents Transforming Growth Factor Alpha (TGF-α) and Epidermal Growth Factor (EGF)-In- duced Human PC-3 Prostate Cancer Cell Proliferation. Interna- tional Journal of Oncology 2003;23:821-9.
  • Petinaria L, Kohn LK, Carvalhob JE, Genari SC. Cytotoxicity of Tamoxifen In Normal And Tumoral Cell Lines And its Ability to In- duce Cellular Transformation in Vitro. Cell Biol Int 2004;28:531-9.
  • Barron-Gonzalez A, Arias-Martinez J, Castro-Romero I. Anties- trogens: Mechanism of Action and Clinical Applications. Salud Publica Mex 2001;43:577-84.
  • Aldous WK, Marean AJ, Dehart MJ, Matej LA, Moore KH. Effects of Tamoxifen on Telomerase Activity in Breast Carcinoma Cell Lines. Cancer 1999;85:1523-9. [CrossRef]
  • Mandlekar S, Hebbar V, Christov K, Kong AN. Pharmacodynam- ics of Tamoxifen and Its 4-Hydroxy and N.Desmethl Metabolites: Activation of Caspases and Induction of Apoptosis in Rat Mam- mary Tumors and in Human Breast Cancer Cell Lines. Cancer Re- search 2000;60:6601-6.
  • Salami S, Karami-Tehrani F. Biochemical Studies of Apoptosis In- duced by Tamoxifen in Estrogen Receptor Positive and Negative Breast Cancer Cell Line. Clin Biochem 2003;36:247-53. [CrossRef]
  • Seeger H, Diesing D, Guckel B, Wallwiener D, Mueck AO, Huober J. Effect of Tamoxifen and 2-Methoxyestradiol Alone and in Combination on Human Breast Cancer Cell Proliferation. J Steroid Biochem Mol Biol 2003;84:255-7. [CrossRef]
  • Mokbel K. The Role of Telomerase in Breast Cancer. Eur J Surg Oncol 2000;26:509-14. [CrossRef]
  • Huang YT, Hwang JJ, Lee PP, Ke FC, Huang JH, Huang CJ, et al. Effects of Luteolin and Quercetin, Inhibitors of Tyrosine Kinase, on Cell Gorwth and Metastasis-associated Properties in A431 Cells Overexpressing Epidermal Growth Factor Receptor. Br J Pharmacol 1999;128:999-1010.
  • Tan WF, Lin LP, Li MH, Zhang YX, Tong YG, Xiao D, et al. Querce- tin, a dietary-derived flavonoid, possesses antiangiogenic poten- tial. Eur J Pharmacol 2003;459:255-62. [CrossRef]
  • Zhang GJ, Kimijima I, Onda M, Kanno M, Sato H, Watanabe T, et al. Tamoxifen-induced Apoptosis in Breast Cancer Cells Relates to Down-regulation of bcl-2, but not bax and bcl-X(L), without Alteration of p53 Protein Levels. Clin Cancer Res 1999;5:2971-7.
  • Perry RR, Kang Y. Greaves B. Effects of Tamoxifen on Growth and Apoptosis of Estrogen-Dependent and -Independent Human Breast Cancer Cells. Annals of surgical Oncology 1995;2:238-45. [CrossRef]
  • Rodgers EH, Grant MH. The effect of the flavonoids, querce- tin, myricetin and epicatechin on the growth and enzyme ac- tivities of MCF-7 human breast cancer cells. Chem Biol Interact 1998;116:213-28. [CrossRef]
  • Choi JA, Kim JY, Lee JY, Kang CM, Kwon HJ, Yoo YD, et al. Induc- tion of Cell Cycle Arrest and Apoptosis in Human Breast Cancer Cells by Quercetin. Int J Oncol 2001;19:837-44. [CrossRef]
  • Maggiolini M, Bonofiglio D, Marsico S, Panno ML, Cenni B, Picard D, et al. Estrogen Receptor α Mediates the Proliferative but not Cytotoxic Dose-Dependent Effects of Two Major Phy- toestrogens on Human Breast Cancer Cells. Molecular Pharma- cology 2001;60:595-602. [CrossRef]
  • Lee TJ, Kim OH, Kim YH, Kim S, Park JW, Kwon TK. Quercetin arrests G2/M phase and induces caspase-dependent cell death in U937 cells. Cancer Lett 2006;240:234-42. [CrossRef]
  • Ong CS, Tran E, Nguyen TT, Ong CK, Lee SK, Lee JJ, et al. Quercetin-induced Growth Inhibition and Cell Death in Naso- pharyngeal Carcinoma Cells Associated with Increase in Bad and Hypohosphorylated Retinoblastoma Expression. Oncol Rep 2004;11:727-33.
  • Kaneuchi M, Sasaki M, Tanaka Y, Sakuragi N, Fijimoto S, Dahiya R. Quercetin Regulates Growth of Ishikawa Cells Through the Sup- pression of EGF and Cyclin D1. Int J Oncol 2003;22:159-64.
  • Kou SM. Antiproliferative Potency of Structurally Distinct Di- etary Flavonoids on Human Colon Cancer Cells. Cancer Lett 1996;110:41-8.
  • Biroccio A, Leonetti C. Telomerase as a New Target for the Treat- ment of Hormone-Refractory Prostate Cancer. Endocr Relat Can- cer 2004;11:407-21. [CrossRef]
  • Kudo M, Naito Z, Yokoyama M, Asano G. Effects of Quercetin and Sunphenon on Responses of Cancer Cells to Heat Shock Damage. Exp Mol Pathol 1999;66:66-75. [CrossRef]
  • Hu S, Liao SK, Pang JH, Chen MC, Chen CH, Hong HS. Screen- ing of Inhibitors of Human Telomerase Reverse Transcriptase in a Cultured Malignant Melanoma Cell Lines. Br J Dermatol 2004;150:367-99. [CrossRef]
  • Brandt S, Heller H, Schuster KD, Grote J. The Tamoxifen Induces Suppression of Cell Viability and Apoptosis in the Human Hepa- toblastoma Cell Line HepG2 via Down-regulation of Telomerase Activity. Liver Int 2004;24:46-54. [CrossRef]
  • Brandt S, Heller H, Schuster K-D, Grote J. The Tamoxifen-induced Suppression of Telomerase Activity in the Human Hepatoblasto- ma Cell Line HepG2: A Result of Post-Translationel Regulation. J Cancer Res Clin Oncol 2005;131:120-8. [CrossRef]
  • Nakayama Y, Sakamoto H, Satoh K, Yamamoto T. Tamoxifen and Gonadal Steroids Inhibit Colon Cancer Growth in Association with Inhibition of Thymidylate Synthase, Survivin and Telomerase Expression Through Estrogen Receptor Beta Mediated System. Cancer Lett 2000;161:63-71. [CrossRef]
  • Caltagirone S, Ranelletti FO, Rinelli A, Maggiano N, Colasante A, Musiani P, et. al. Interaction with Type II Estrogen Binding Sites and Antiproliferative Activity of Tamoxifen and Quercetin in Human Non- Small-Cell Lung Cancer. Am J Respir Cell Mol Biol 1997;17:51-9.

Evaluation of Effects of Quercetin (3, 3', 4', 5, 7-pentohidroxyflavon) on Apoptosis and Telomerase Enzyme Activity in MCF-7 and NIH-3T3 Cell Lines Compared with Tamoxifen

Year 2011, Volume: 2011 Issue: 3, 293 - 299, 01.03.2011
https://doi.org/10.5174/tutfd.2010.03372.3

Abstract

References

  • Bentrem DJ, Gaiha P, Jordan VC. Oestrogens, Oestrogen Recep- tors and Breast Cancer. EJC 2003;1:1-12. [CrossRef]
  • Imyanitov EN, Hanson KP. Mechanism of Breast Cancer. Drug dis- covery today: disease mechanism 2004;1:235-45. [CrossRef]
  • Parton M, Dowsett M, Smith L. Studies of Apoptosis in Breast Cancer. BMJ 2001;322:1528-32. [CrossRef]
  • Lowe SW, Lin AW. Apoptosis in Cancer. Carcinogenesis 2000;21:485-95. [CrossRef]
  • Gilley D, Tanaka H, Herbert BS. Telomere Dysfunciton in Aging and Cancer. Int J Biochem Cell Biol 2005;37:1000-13. [CrossRef]
  • Falchetti A, Becherini L, Martineti V, Morelli A, Benvenuti S, Picar- iello L, et al. Telomerase Repeat Amplification Protocol (TRAP): A New Molecular Marker for Parathyroid Carcinoma. Biochem Biophys Res Commun 1999;265:252-5. [CrossRef]
  • Başaran A. Hücresel Yaşlanma ve Hücre Ölümsüzlüğünde Telom- eraz Enzim Kompleksi. Sendrom 2002;14:90-5.
  • Conquer JA, Maiani G, Azzini E, Raguzzini A, Holub BJ. Supple- mentation with Quercetin Markedly Increases Plasma Quercetin Concentration without Effect on Selected Risk Factors for Heart Disease in Healthy Subjects. J Nutr 1998;128:593-7.
  • Adebamowo CA, Cho E, Sampson L, Katan MB, Spiegelman D, Willett WC et al. Dietary Flavonos and Flavonol-Rich Foods In- take and Risk of Breast Cancer. International Journal of Cancer 2005;114:628-33. [CrossRef]
  • Kuo PC, Liu HF, Chao JI. Survivin and p53 modulate quercetin-in- duced cell growthinhibition and apoptosis in human lung carcino- ma cells. The Journal of Biological Chemistry 2004;279:55875-85. [CrossRef]
  • Huynh H, Nguyen TTT, Chan E, Tran E. Inhibition of ErbB2 and ErbB-3 Expression by Quercetin Prevents Transforming Growth Factor Alpha (TGF-α) and Epidermal Growth Factor (EGF)-In- duced Human PC-3 Prostate Cancer Cell Proliferation. Interna- tional Journal of Oncology 2003;23:821-9.
  • Petinaria L, Kohn LK, Carvalhob JE, Genari SC. Cytotoxicity of Tamoxifen In Normal And Tumoral Cell Lines And its Ability to In- duce Cellular Transformation in Vitro. Cell Biol Int 2004;28:531-9.
  • Barron-Gonzalez A, Arias-Martinez J, Castro-Romero I. Anties- trogens: Mechanism of Action and Clinical Applications. Salud Publica Mex 2001;43:577-84.
  • Aldous WK, Marean AJ, Dehart MJ, Matej LA, Moore KH. Effects of Tamoxifen on Telomerase Activity in Breast Carcinoma Cell Lines. Cancer 1999;85:1523-9. [CrossRef]
  • Mandlekar S, Hebbar V, Christov K, Kong AN. Pharmacodynam- ics of Tamoxifen and Its 4-Hydroxy and N.Desmethl Metabolites: Activation of Caspases and Induction of Apoptosis in Rat Mam- mary Tumors and in Human Breast Cancer Cell Lines. Cancer Re- search 2000;60:6601-6.
  • Salami S, Karami-Tehrani F. Biochemical Studies of Apoptosis In- duced by Tamoxifen in Estrogen Receptor Positive and Negative Breast Cancer Cell Line. Clin Biochem 2003;36:247-53. [CrossRef]
  • Seeger H, Diesing D, Guckel B, Wallwiener D, Mueck AO, Huober J. Effect of Tamoxifen and 2-Methoxyestradiol Alone and in Combination on Human Breast Cancer Cell Proliferation. J Steroid Biochem Mol Biol 2003;84:255-7. [CrossRef]
  • Mokbel K. The Role of Telomerase in Breast Cancer. Eur J Surg Oncol 2000;26:509-14. [CrossRef]
  • Huang YT, Hwang JJ, Lee PP, Ke FC, Huang JH, Huang CJ, et al. Effects of Luteolin and Quercetin, Inhibitors of Tyrosine Kinase, on Cell Gorwth and Metastasis-associated Properties in A431 Cells Overexpressing Epidermal Growth Factor Receptor. Br J Pharmacol 1999;128:999-1010.
  • Tan WF, Lin LP, Li MH, Zhang YX, Tong YG, Xiao D, et al. Querce- tin, a dietary-derived flavonoid, possesses antiangiogenic poten- tial. Eur J Pharmacol 2003;459:255-62. [CrossRef]
  • Zhang GJ, Kimijima I, Onda M, Kanno M, Sato H, Watanabe T, et al. Tamoxifen-induced Apoptosis in Breast Cancer Cells Relates to Down-regulation of bcl-2, but not bax and bcl-X(L), without Alteration of p53 Protein Levels. Clin Cancer Res 1999;5:2971-7.
  • Perry RR, Kang Y. Greaves B. Effects of Tamoxifen on Growth and Apoptosis of Estrogen-Dependent and -Independent Human Breast Cancer Cells. Annals of surgical Oncology 1995;2:238-45. [CrossRef]
  • Rodgers EH, Grant MH. The effect of the flavonoids, querce- tin, myricetin and epicatechin on the growth and enzyme ac- tivities of MCF-7 human breast cancer cells. Chem Biol Interact 1998;116:213-28. [CrossRef]
  • Choi JA, Kim JY, Lee JY, Kang CM, Kwon HJ, Yoo YD, et al. Induc- tion of Cell Cycle Arrest and Apoptosis in Human Breast Cancer Cells by Quercetin. Int J Oncol 2001;19:837-44. [CrossRef]
  • Maggiolini M, Bonofiglio D, Marsico S, Panno ML, Cenni B, Picard D, et al. Estrogen Receptor α Mediates the Proliferative but not Cytotoxic Dose-Dependent Effects of Two Major Phy- toestrogens on Human Breast Cancer Cells. Molecular Pharma- cology 2001;60:595-602. [CrossRef]
  • Lee TJ, Kim OH, Kim YH, Kim S, Park JW, Kwon TK. Quercetin arrests G2/M phase and induces caspase-dependent cell death in U937 cells. Cancer Lett 2006;240:234-42. [CrossRef]
  • Ong CS, Tran E, Nguyen TT, Ong CK, Lee SK, Lee JJ, et al. Quercetin-induced Growth Inhibition and Cell Death in Naso- pharyngeal Carcinoma Cells Associated with Increase in Bad and Hypohosphorylated Retinoblastoma Expression. Oncol Rep 2004;11:727-33.
  • Kaneuchi M, Sasaki M, Tanaka Y, Sakuragi N, Fijimoto S, Dahiya R. Quercetin Regulates Growth of Ishikawa Cells Through the Sup- pression of EGF and Cyclin D1. Int J Oncol 2003;22:159-64.
  • Kou SM. Antiproliferative Potency of Structurally Distinct Di- etary Flavonoids on Human Colon Cancer Cells. Cancer Lett 1996;110:41-8.
  • Biroccio A, Leonetti C. Telomerase as a New Target for the Treat- ment of Hormone-Refractory Prostate Cancer. Endocr Relat Can- cer 2004;11:407-21. [CrossRef]
  • Kudo M, Naito Z, Yokoyama M, Asano G. Effects of Quercetin and Sunphenon on Responses of Cancer Cells to Heat Shock Damage. Exp Mol Pathol 1999;66:66-75. [CrossRef]
  • Hu S, Liao SK, Pang JH, Chen MC, Chen CH, Hong HS. Screen- ing of Inhibitors of Human Telomerase Reverse Transcriptase in a Cultured Malignant Melanoma Cell Lines. Br J Dermatol 2004;150:367-99. [CrossRef]
  • Brandt S, Heller H, Schuster KD, Grote J. The Tamoxifen Induces Suppression of Cell Viability and Apoptosis in the Human Hepa- toblastoma Cell Line HepG2 via Down-regulation of Telomerase Activity. Liver Int 2004;24:46-54. [CrossRef]
  • Brandt S, Heller H, Schuster K-D, Grote J. The Tamoxifen-induced Suppression of Telomerase Activity in the Human Hepatoblasto- ma Cell Line HepG2: A Result of Post-Translationel Regulation. J Cancer Res Clin Oncol 2005;131:120-8. [CrossRef]
  • Nakayama Y, Sakamoto H, Satoh K, Yamamoto T. Tamoxifen and Gonadal Steroids Inhibit Colon Cancer Growth in Association with Inhibition of Thymidylate Synthase, Survivin and Telomerase Expression Through Estrogen Receptor Beta Mediated System. Cancer Lett 2000;161:63-71. [CrossRef]
  • Caltagirone S, Ranelletti FO, Rinelli A, Maggiano N, Colasante A, Musiani P, et. al. Interaction with Type II Estrogen Binding Sites and Antiproliferative Activity of Tamoxifen and Quercetin in Human Non- Small-Cell Lung Cancer. Am J Respir Cell Mol Biol 1997;17:51-9.
There are 36 citations in total.

Details

Primary Language English
Subjects Health Care Administration
Journal Section Articles
Authors

Ayşe Ak This is me

Ayşe Başaran This is me

Miris Dikmen This is me

İrfan Değirmenci This is me

Didem Turgut Coşan This is me

Hasan Veysi Güneş This is me

Publication Date March 1, 2011
Published in Issue Year 2011 Volume: 2011 Issue: 3

Cite

APA Ak, A., Başaran, A., Dikmen, M., Değirmenci, İ., et al. (2011). Evaluation of Effects of Quercetin (3, 3’, 4’, 5, 7-pentohidroxyflavon) on Apoptosis and Telomerase Enzyme Activity in MCF-7 and NIH-3T3 Cell Lines Compared with Tamoxifen. Balkan Medical Journal, 2011(3), 293-299. https://doi.org/10.5174/tutfd.2010.03372.3
AMA Ak A, Başaran A, Dikmen M, Değirmenci İ, Turgut Coşan D, Güneş HV. Evaluation of Effects of Quercetin (3, 3’, 4’, 5, 7-pentohidroxyflavon) on Apoptosis and Telomerase Enzyme Activity in MCF-7 and NIH-3T3 Cell Lines Compared with Tamoxifen. Balkan Medical Journal. March 2011;2011(3):293-299. doi:10.5174/tutfd.2010.03372.3
Chicago Ak, Ayşe, Ayşe Başaran, Miris Dikmen, İrfan Değirmenci, Didem Turgut Coşan, and Hasan Veysi Güneş. “Evaluation of Effects of Quercetin (3, 3’, 4’, 5, 7-Pentohidroxyflavon) on Apoptosis and Telomerase Enzyme Activity in MCF-7 and NIH-3T3 Cell Lines Compared With Tamoxifen”. Balkan Medical Journal 2011, no. 3 (March 2011): 293-99. https://doi.org/10.5174/tutfd.2010.03372.3.
EndNote Ak A, Başaran A, Dikmen M, Değirmenci İ, Turgut Coşan D, Güneş HV (March 1, 2011) Evaluation of Effects of Quercetin (3, 3’, 4’, 5, 7-pentohidroxyflavon) on Apoptosis and Telomerase Enzyme Activity in MCF-7 and NIH-3T3 Cell Lines Compared with Tamoxifen. Balkan Medical Journal 2011 3 293–299.
IEEE A. Ak, A. Başaran, M. Dikmen, İ. Değirmenci, D. Turgut Coşan, and H. V. Güneş, “Evaluation of Effects of Quercetin (3, 3’, 4’, 5, 7-pentohidroxyflavon) on Apoptosis and Telomerase Enzyme Activity in MCF-7 and NIH-3T3 Cell Lines Compared with Tamoxifen”, Balkan Medical Journal, vol. 2011, no. 3, pp. 293–299, 2011, doi: 10.5174/tutfd.2010.03372.3.
ISNAD Ak, Ayşe et al. “Evaluation of Effects of Quercetin (3, 3’, 4’, 5, 7-Pentohidroxyflavon) on Apoptosis and Telomerase Enzyme Activity in MCF-7 and NIH-3T3 Cell Lines Compared With Tamoxifen”. Balkan Medical Journal 2011/3 (March 2011), 293-299. https://doi.org/10.5174/tutfd.2010.03372.3.
JAMA Ak A, Başaran A, Dikmen M, Değirmenci İ, Turgut Coşan D, Güneş HV. Evaluation of Effects of Quercetin (3, 3’, 4’, 5, 7-pentohidroxyflavon) on Apoptosis and Telomerase Enzyme Activity in MCF-7 and NIH-3T3 Cell Lines Compared with Tamoxifen. Balkan Medical Journal. 2011;2011:293–299.
MLA Ak, Ayşe et al. “Evaluation of Effects of Quercetin (3, 3’, 4’, 5, 7-Pentohidroxyflavon) on Apoptosis and Telomerase Enzyme Activity in MCF-7 and NIH-3T3 Cell Lines Compared With Tamoxifen”. Balkan Medical Journal, vol. 2011, no. 3, 2011, pp. 293-9, doi:10.5174/tutfd.2010.03372.3.
Vancouver Ak A, Başaran A, Dikmen M, Değirmenci İ, Turgut Coşan D, Güneş HV. Evaluation of Effects of Quercetin (3, 3’, 4’, 5, 7-pentohidroxyflavon) on Apoptosis and Telomerase Enzyme Activity in MCF-7 and NIH-3T3 Cell Lines Compared with Tamoxifen. Balkan Medical Journal. 2011;2011(3):293-9.