P53 But Not Cyclin E Acts in A Negative Regulatory Loop to Control HER-2 Expression in MCF-7 Breast Carcinoma Cell Line

  • Hamed Montazeri Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran.
  • Saeid Bouzari Mail Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran.
  • Kayhan Azadmanesh Department of Virology, Pasteur Institute of Iran, Tehran, Iran.
  • Seyed Nasser Ostad Department of Toxicology Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.
  • Mohammad Hossein Ghahremani Department of Toxicology-Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran. AND Department of Molecular Medicine, School of Advanced Technology in Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Breast cancer, Cyclin E, HER-2/neu, p53


Cyclin E, HER-2 and p53, are considered as major prognostic markers in breast cancer. As they are related in patho-clinical level, we aimed to check if they have any direct interaction on expression of each other. To study the effect of cyclin E on HER-2 expression, cell lines stably overexpressing cyclin E or its low molecular weight (LMW) isoforms were generated. To understand the results of p53 silencing either alone or in combination with cyclin E overexpression, we created three different p53 stably knocked down cell lines. Protein expression was analyzed by western blot, HER-2 expression in the established cell lines were determined using SYBR green real time PCR and data analyzed by REST software. Results indicate that HER-2 expression is only downregulated following p53 silencing and none of cyclin E isoforms can alter its expression. The presence of cyclin E isoforms in p53 silenced clones also does not altered HER-2 expression. Given the fact that p53 degradation is increased by HER-2 overexpression, these data can draw a regulatory loop in which a non-mutated functional p53 and HER-2 can bidirectionally regulate the expression of these two genes. This study improves our understandings of these pathways and these proteins can be introduced either as a marker or as a target in cancer treatment.


Senn HJ, Thurlimann B, Goldhirsch A, Wood WC, Gelber RD, Coates AS. Comments on the St. Gallen Consensus 2003 on the Primary Therapy of Early Breast Cancer.Breast 2003;12(6):569-82.

Sherr CJ. The Pezcoller lecture: cancer cell cycles revisited. Cancer Res 2000;60(14):3689-95.

Nevins JR. E2F: a link between the Rb tumor suppressor protein and viral oncoproteins. Science 1992;258(5081):424-9.

Ohtani K, DeGregori J, Nevins JR. Regulation of the cyclin E gene by transcription factor E2F1. Proc Natl Acad Sci U S A 1995;92(26):12146-50.

Hwang HC, Clurman BE. Cyclin E in normal and neoplastic cell cycles. Oncogene 2005; 24(17):2776-86.

Donnellan R, Chetty R. Cyclin E in human cancers. FASEB J 1999;13(8):773-80.

Keyomarsi K, Pardee AB. Redundant cyclin overexpression and gene amplification in breast cancer cells. Proc Natl Acad Sci U S A 1993;90(3):1112-6.

Keyomarsi K, Herliczek TW. The role of cyclin E in cell proliferation, development and cancer. Prog Cell Cycle Res 1997;3:171-91.

Keyomarsi K, O'Leary N, Molnar G, Lees E, Fingert HJ, Pardee AB. Cyclin E, a potential prognostic marker for breast cancer. Cancer Res 1994;54(2):380-5.

Wingate H, Zhang N, McGarhen MJ, Bedrosian I, Harper JW, Keyomarsi K. The tumor-specific hyperactive forms of cyclin E are resistant to inhibition by p21 and p27. JBiol Chem 2005;280(15):15148-57.

Akli S, Bui T, Wingate H, Biernacka A, Moulder S,Tucker SL, Hunt KK, Keyomarsi K. Low-molecularweight cyclin E can bypass letrozole-induced G1 arrest in human breast cancer cells and tumors. Clin Cancer Res 2010;16(4):1179-90.

Akli S, Zheng PJ, Multani AS, Wingate HF, Pathak S, Zhang N, Tucker SL, Chang S, Keyomarsi K. Tumorspecificlow molecular weight forms of cyclin E induce genomic instability and resistance to p21, p27, and antiestrogens in breast cancer. Cancer Res2004;64(9):3198-208.

Barton MC, Akli S, Keyomarsi K. Deregulation of cyclin E meets dysfunction in p53: closing the escape hatch on breast cancer. J Cell Physiol 2006;209(3):686-94.

Berns EM, Klijn JG, van Staveren IL, Portengen H,Noordegraaf E, Foekens JA. Prevalence of amplification of the oncogenes c-myc, HER2/neu, and int-2 in one thousand human breast tumours: correlation with steroid receptors. Eur J Cancer 1992;28(2-3):697-700.

Timms JF, White SL, O'Hare MJ, Waterfield MD. Effects of ErbB-2 overexpression on mitogenic signalling and cell cycle progression in human breast luminal epithelial cells. Oncogene 2002;21(43):6573-86.

Le XF, Pruefer F, Bast RC, Jr. HER2-targeting antibodies modulate the cyclin-dependent kinase inhibitor p27Kip1 via multiple signaling pathways. Cell Cycle 2005;4(1):87-95.

Potemski P, Kusinska R, Watala C, Pluciennik E, Bednarek AK, Kordek R. Cyclin E expression in breast cancer correlates with negative steroid receptor status, HER2 expression, tumor grade and proliferation. J Exp Clin Cancer Res 2006;25(1):59-64.

Harwell RM, Porter DC, Danes C, Keyomarsi K. Processing of cyclin E differs between normal and tumor breast cells. Cancer Res 2000;60(2):481-9.

Pfaffl MW, Horgan GW, Dempfle L. Relative expression software tool (REST) for group-wise comparison and statistical analysis of relative expression results in realtime PCR. Nucleic Acids Res 2002;30(9):e36.

Porter DC, Zhang N, Danes C, McGahren MJ, Harwell RM, Faruki S, Keyomarsi K. Tumor-specific proteolytic processing of cyclin E generates hyperactive lowermolecular- weight forms. Mol Cell Biol 2001;21(18):6254-69.

Zhou BP, Liao Y, Xia W, Zou Y, Spohn B, Hung MC. HER-2/neu induces p53 ubiquitination via Akt-mediated MDM2 phosphorylation. Nat Cell Biol 2001;3(11):973-82.

Mittendorf EA, Liu Y, Tucker SL, McKenzie T, Qiao N, Akli S, Biernacka A, Meijer L, Keyomarsi K, Hunt KK. A novel interaction between HER2/neu and cyclin E in breast cancer. Oncogene 2010;29(27):3896-907.

How to Cite
Montazeri H, Bouzari S, Azadmanesh K, Ostad SN, Ghahremani MH. P53 But Not Cyclin E Acts in A Negative Regulatory Loop to Control HER-2 Expression in MCF-7 Breast Carcinoma Cell Line. Acta Med Iran. 51(8):513-519.