Oleic acid, the main monounsaturated fatty acid of olive oil, suppresses Her-2/neu (erb B-2) expression and synergistically enhances the growth inhibitory effects of trastuzumab (Herceptin™) in breast cancer cells with Her-2/neu oncogene amplification

J. A. Menendez, L. Vellon, R. Colomer, Ruth Lupu

Research output: Contribution to journalArticle

153 Citations (Scopus)

Abstract

Background: The relationship between the intake of olive oil, the richest dietary source of the mono-unsaturated fatty acid oleic acid (OA; 18: 1n-9), and breast cancer risk and progression has become a controversial issue. Moreover, it has been suggested that the protective effects of olive oil against breast cancer may be due to some other components of the oil rather than to a direct effect of OA. Methods: Using flow cytometry, western blotting, immunofluorescence microscopy, metabolic status (MTT), soft-agar colony formation, enzymatic in situ labeling of apoptosis-induced DNA double-strand breaks (TUNEL assay analyses), and caspase-3-dependent poly-ADP ribose polymerase (PARP) cleavage assays, we characterized the effects of exogenous supplementation with OA on the expression of Her-2/neu oncogene, which plays an active role in breast cancer etiology and progression. In addition, we investigated the effects of OA on the efficacy of trastuzumab (Herceptin™), a humanized monoclonal antibody binding with high affinity to the ectodomain of the Her-2/neu-coded p185Her-2/neu oncoprotein. To study these issues we used BT-474 and SKBr-3 breast cancer cells, which naturally exhibit amplification of the Her-2/neu oncogene. Results: Flow cytometric analyses demonstrated a dramatic (up to 46%) reduction of cell surface-associated p185Her-2/neu following treatment of the Her-2/neu-overexpressors BT-474 and SK-Br3 with OA. Indeed, this effect was comparable to that found following exposure to optimal concentrations of trastuzumab (up to 48% reduction with 20 μg /ml trastuzumab). Remarkably, the concurrent exposure to OA and suboptimal concentrations of trastuzumab (5 μg/ml) synergistically down-regulated Her-2/neu expression, as determined by flow cytometry (up to 70% reduction), immunoblotting, and immunofluorescence microscopy studies. The nature of the cytotoxic interaction between OA and trastuzumab revealed a strong synergism, as assessed by MTT-based cell viability and anchorage-independent soft-agar colony formation assays. Moreover, OA co-exposure synergistically enhanced trastuzumab efficacy towards Her-2/neu overexpressors by promoting DNA fragmentation associated with apoptotic cell death, as confirmed by TUNEL and caspase-3-dependent PARP cleavage. In addition, treatment with OA and trastuzumab dramatically increased both the expression and the nuclear accumulation of p27Kip1, a cyclin-dependent kinase inhibitor playing a key role in the onset and progression of Her-2/neu-related breast cancer. Finally, OA co-exposure significantly enhanced the ability of trastuzumab to inhibit signaling pathways downstream of Her-2/neu, including phosphoproteins such as AKT and MAPK. Conclusions: These findings demonstrate that OA, the main monounsaturated fatty acid of olive oil, suppresses Her-2/neu overexpression, which, in turn, interacts synergistically with anti-Her-2/neu immunotherapy by promoting apoptotic cell death of breast cancer cells with Her-2/neu oncogene amplification. This previously unrecognized property of OA offers a novel molecular mechanism by which individual fatty acids may regulate the malignant behavior of breast cancer cells and therefore be helpful in the design of future epidemiological studies and, eventually, dietary counseling.

Original languageEnglish (US)
Pages (from-to)359-371
Number of pages13
JournalAnnals of Oncology
Volume16
Issue number3
DOIs
StatePublished - Mar 2005
Externally publishedYes

Fingerprint

Monounsaturated Fatty Acids
Oleic Acid
Oncogenes
Breast Neoplasms
Growth
Poly(ADP-ribose) Polymerases
In Situ Nick-End Labeling
Fluorescence Microscopy
Caspase 3
Agar
Flow Cytometry
Cell Death
Antibodies, Monoclonal, Humanized
Olive Oil
Trastuzumab
Aptitude
Double-Stranded DNA Breaks
Cyclin-Dependent Kinases
Phosphoproteins
Oncogene Proteins

Keywords

  • Apoptosis
  • Breast cancer
  • Fatty acids
  • Her-2/neu
  • Oleic acid
  • Trastuzumab

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

Cite this

@article{6dc396e92fd4412fbd051e97cfc7becb,
title = "Oleic acid, the main monounsaturated fatty acid of olive oil, suppresses Her-2/neu (erb B-2) expression and synergistically enhances the growth inhibitory effects of trastuzumab (Herceptin™) in breast cancer cells with Her-2/neu oncogene amplification",
abstract = "Background: The relationship between the intake of olive oil, the richest dietary source of the mono-unsaturated fatty acid oleic acid (OA; 18: 1n-9), and breast cancer risk and progression has become a controversial issue. Moreover, it has been suggested that the protective effects of olive oil against breast cancer may be due to some other components of the oil rather than to a direct effect of OA. Methods: Using flow cytometry, western blotting, immunofluorescence microscopy, metabolic status (MTT), soft-agar colony formation, enzymatic in situ labeling of apoptosis-induced DNA double-strand breaks (TUNEL assay analyses), and caspase-3-dependent poly-ADP ribose polymerase (PARP) cleavage assays, we characterized the effects of exogenous supplementation with OA on the expression of Her-2/neu oncogene, which plays an active role in breast cancer etiology and progression. In addition, we investigated the effects of OA on the efficacy of trastuzumab (Herceptin™), a humanized monoclonal antibody binding with high affinity to the ectodomain of the Her-2/neu-coded p185Her-2/neu oncoprotein. To study these issues we used BT-474 and SKBr-3 breast cancer cells, which naturally exhibit amplification of the Her-2/neu oncogene. Results: Flow cytometric analyses demonstrated a dramatic (up to 46{\%}) reduction of cell surface-associated p185Her-2/neu following treatment of the Her-2/neu-overexpressors BT-474 and SK-Br3 with OA. Indeed, this effect was comparable to that found following exposure to optimal concentrations of trastuzumab (up to 48{\%} reduction with 20 μg /ml trastuzumab). Remarkably, the concurrent exposure to OA and suboptimal concentrations of trastuzumab (5 μg/ml) synergistically down-regulated Her-2/neu expression, as determined by flow cytometry (up to 70{\%} reduction), immunoblotting, and immunofluorescence microscopy studies. The nature of the cytotoxic interaction between OA and trastuzumab revealed a strong synergism, as assessed by MTT-based cell viability and anchorage-independent soft-agar colony formation assays. Moreover, OA co-exposure synergistically enhanced trastuzumab efficacy towards Her-2/neu overexpressors by promoting DNA fragmentation associated with apoptotic cell death, as confirmed by TUNEL and caspase-3-dependent PARP cleavage. In addition, treatment with OA and trastuzumab dramatically increased both the expression and the nuclear accumulation of p27Kip1, a cyclin-dependent kinase inhibitor playing a key role in the onset and progression of Her-2/neu-related breast cancer. Finally, OA co-exposure significantly enhanced the ability of trastuzumab to inhibit signaling pathways downstream of Her-2/neu, including phosphoproteins such as AKT and MAPK. Conclusions: These findings demonstrate that OA, the main monounsaturated fatty acid of olive oil, suppresses Her-2/neu overexpression, which, in turn, interacts synergistically with anti-Her-2/neu immunotherapy by promoting apoptotic cell death of breast cancer cells with Her-2/neu oncogene amplification. This previously unrecognized property of OA offers a novel molecular mechanism by which individual fatty acids may regulate the malignant behavior of breast cancer cells and therefore be helpful in the design of future epidemiological studies and, eventually, dietary counseling.",
keywords = "Apoptosis, Breast cancer, Fatty acids, Her-2/neu, Oleic acid, Trastuzumab",
author = "Menendez, {J. A.} and L. Vellon and R. Colomer and Ruth Lupu",
year = "2005",
month = "3",
doi = "10.1093/annonc/mdi090",
language = "English (US)",
volume = "16",
pages = "359--371",
journal = "Annals of Oncology",
issn = "0923-7534",
publisher = "Oxford University Press",
number = "3",

}

TY - JOUR

T1 - Oleic acid, the main monounsaturated fatty acid of olive oil, suppresses Her-2/neu (erb B-2) expression and synergistically enhances the growth inhibitory effects of trastuzumab (Herceptin™) in breast cancer cells with Her-2/neu oncogene amplification

AU - Menendez, J. A.

AU - Vellon, L.

AU - Colomer, R.

AU - Lupu, Ruth

PY - 2005/3

Y1 - 2005/3

N2 - Background: The relationship between the intake of olive oil, the richest dietary source of the mono-unsaturated fatty acid oleic acid (OA; 18: 1n-9), and breast cancer risk and progression has become a controversial issue. Moreover, it has been suggested that the protective effects of olive oil against breast cancer may be due to some other components of the oil rather than to a direct effect of OA. Methods: Using flow cytometry, western blotting, immunofluorescence microscopy, metabolic status (MTT), soft-agar colony formation, enzymatic in situ labeling of apoptosis-induced DNA double-strand breaks (TUNEL assay analyses), and caspase-3-dependent poly-ADP ribose polymerase (PARP) cleavage assays, we characterized the effects of exogenous supplementation with OA on the expression of Her-2/neu oncogene, which plays an active role in breast cancer etiology and progression. In addition, we investigated the effects of OA on the efficacy of trastuzumab (Herceptin™), a humanized monoclonal antibody binding with high affinity to the ectodomain of the Her-2/neu-coded p185Her-2/neu oncoprotein. To study these issues we used BT-474 and SKBr-3 breast cancer cells, which naturally exhibit amplification of the Her-2/neu oncogene. Results: Flow cytometric analyses demonstrated a dramatic (up to 46%) reduction of cell surface-associated p185Her-2/neu following treatment of the Her-2/neu-overexpressors BT-474 and SK-Br3 with OA. Indeed, this effect was comparable to that found following exposure to optimal concentrations of trastuzumab (up to 48% reduction with 20 μg /ml trastuzumab). Remarkably, the concurrent exposure to OA and suboptimal concentrations of trastuzumab (5 μg/ml) synergistically down-regulated Her-2/neu expression, as determined by flow cytometry (up to 70% reduction), immunoblotting, and immunofluorescence microscopy studies. The nature of the cytotoxic interaction between OA and trastuzumab revealed a strong synergism, as assessed by MTT-based cell viability and anchorage-independent soft-agar colony formation assays. Moreover, OA co-exposure synergistically enhanced trastuzumab efficacy towards Her-2/neu overexpressors by promoting DNA fragmentation associated with apoptotic cell death, as confirmed by TUNEL and caspase-3-dependent PARP cleavage. In addition, treatment with OA and trastuzumab dramatically increased both the expression and the nuclear accumulation of p27Kip1, a cyclin-dependent kinase inhibitor playing a key role in the onset and progression of Her-2/neu-related breast cancer. Finally, OA co-exposure significantly enhanced the ability of trastuzumab to inhibit signaling pathways downstream of Her-2/neu, including phosphoproteins such as AKT and MAPK. Conclusions: These findings demonstrate that OA, the main monounsaturated fatty acid of olive oil, suppresses Her-2/neu overexpression, which, in turn, interacts synergistically with anti-Her-2/neu immunotherapy by promoting apoptotic cell death of breast cancer cells with Her-2/neu oncogene amplification. This previously unrecognized property of OA offers a novel molecular mechanism by which individual fatty acids may regulate the malignant behavior of breast cancer cells and therefore be helpful in the design of future epidemiological studies and, eventually, dietary counseling.

AB - Background: The relationship between the intake of olive oil, the richest dietary source of the mono-unsaturated fatty acid oleic acid (OA; 18: 1n-9), and breast cancer risk and progression has become a controversial issue. Moreover, it has been suggested that the protective effects of olive oil against breast cancer may be due to some other components of the oil rather than to a direct effect of OA. Methods: Using flow cytometry, western blotting, immunofluorescence microscopy, metabolic status (MTT), soft-agar colony formation, enzymatic in situ labeling of apoptosis-induced DNA double-strand breaks (TUNEL assay analyses), and caspase-3-dependent poly-ADP ribose polymerase (PARP) cleavage assays, we characterized the effects of exogenous supplementation with OA on the expression of Her-2/neu oncogene, which plays an active role in breast cancer etiology and progression. In addition, we investigated the effects of OA on the efficacy of trastuzumab (Herceptin™), a humanized monoclonal antibody binding with high affinity to the ectodomain of the Her-2/neu-coded p185Her-2/neu oncoprotein. To study these issues we used BT-474 and SKBr-3 breast cancer cells, which naturally exhibit amplification of the Her-2/neu oncogene. Results: Flow cytometric analyses demonstrated a dramatic (up to 46%) reduction of cell surface-associated p185Her-2/neu following treatment of the Her-2/neu-overexpressors BT-474 and SK-Br3 with OA. Indeed, this effect was comparable to that found following exposure to optimal concentrations of trastuzumab (up to 48% reduction with 20 μg /ml trastuzumab). Remarkably, the concurrent exposure to OA and suboptimal concentrations of trastuzumab (5 μg/ml) synergistically down-regulated Her-2/neu expression, as determined by flow cytometry (up to 70% reduction), immunoblotting, and immunofluorescence microscopy studies. The nature of the cytotoxic interaction between OA and trastuzumab revealed a strong synergism, as assessed by MTT-based cell viability and anchorage-independent soft-agar colony formation assays. Moreover, OA co-exposure synergistically enhanced trastuzumab efficacy towards Her-2/neu overexpressors by promoting DNA fragmentation associated with apoptotic cell death, as confirmed by TUNEL and caspase-3-dependent PARP cleavage. In addition, treatment with OA and trastuzumab dramatically increased both the expression and the nuclear accumulation of p27Kip1, a cyclin-dependent kinase inhibitor playing a key role in the onset and progression of Her-2/neu-related breast cancer. Finally, OA co-exposure significantly enhanced the ability of trastuzumab to inhibit signaling pathways downstream of Her-2/neu, including phosphoproteins such as AKT and MAPK. Conclusions: These findings demonstrate that OA, the main monounsaturated fatty acid of olive oil, suppresses Her-2/neu overexpression, which, in turn, interacts synergistically with anti-Her-2/neu immunotherapy by promoting apoptotic cell death of breast cancer cells with Her-2/neu oncogene amplification. This previously unrecognized property of OA offers a novel molecular mechanism by which individual fatty acids may regulate the malignant behavior of breast cancer cells and therefore be helpful in the design of future epidemiological studies and, eventually, dietary counseling.

KW - Apoptosis

KW - Breast cancer

KW - Fatty acids

KW - Her-2/neu

KW - Oleic acid

KW - Trastuzumab

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U2 - 10.1093/annonc/mdi090

DO - 10.1093/annonc/mdi090

M3 - Article

VL - 16

SP - 359

EP - 371

JO - Annals of Oncology

JF - Annals of Oncology

SN - 0923-7534

IS - 3

ER -