Silibinin meglumine, a water-soluble form of milk thistle silymarin, is an orally active anti-cancer agent that impedes the epithelial-to-mesenchymal transition (EMT) in EGFR-mutant non-small-cell lung carcinoma cells.

Silibinin is the primary active constituent of a crude extract (silymarin) from milk thistle plant (Silybum marianum) seeds. We explored the ability of an oral milk thistle extract formulation that was enriched with a water-soluble form of silibinin complexed with the amino-sugar meglumine to inhibit the growth of non-small-cell lung carcinoma (NSCLC) mouse xenografts. As a single agent, oral silibinin meglumine notably decreased the overall volumes of NSCLC tumors as efficiently as did the EGFR tyrosine kinase inhibitor (TKI) gefitinib. Concurrent treatment with silibinin meglumine impeded the regrowth of gefitinib-unresponsive tumors, resulting in drastic tumor growth prevention. Because the epithelial-to-mesenchymal transition (EMT) is required by a multiplicity of mechanisms of resistance to EGFR TKIs, we evaluated the ability of silibinin meglumine to impede the EMT in vitro and in vivo. Silibinin-meglumine efficiently prevented the loss of markers associated with a polarized epithelial phenotype as well as the de novo synthesis of proteins associated with the mesenchymal morphology of transitioning cells. Our current findings with this non-toxic, orally active, and water-soluble silibinin formulation might facilitate the design of clinical trials to test the administration of silibinin meglumine-containing injections, granules, or beverages in combination with EGFR TKIs in patients with EGFR-mutated NSCLC.

Xenohormetic and anti-aging activity of secoiridoid polyphenols present in extra virgin olive oil: a new family of gerosuppressant agents.

Aging can be viewed as a quasi-programmed phenomenon driven by the overactivation of the nutrient-sensing mTOR gerogene. mTOR-driven aging can be triggered or accelerated by a decline or loss of responsiveness to activation of the energy-sensing protein AMPK, a critical gerosuppressor of mTOR. The occurrence of age-related diseases, therefore, reflects the synergistic interaction between our evolutionary path to sedentarism, which chronically increases a number of mTOR activating gero-promoters (e.g., food, growth factors, cytokines and insulin) and the "defective design" of central metabolic integrators such as mTOR and AMPK. Our laboratories at the Bioactive Food Component Platform in Spain have initiated a systematic approach to molecularly elucidate and clinically explore whether the "xenohormesis hypothesis," which states that stress-induced synthesis of plant polyphenols and many other phytochemicals provides an environmental chemical signature that upregulates stress-resistance pathways in plant consumers, can be explained in terms of the reactivity of the AMPK/mTOR-axis to so-called xenohormetins. Here, we explore the AMPK/mTOR-xenohormetic nature of complex polyphenols naturally present in extra virgin olive oil (EVOO), a pivotal component of the Mediterranean style diet that has been repeatedly associated with a reduction in age-related morbid conditions and longer life expectancy. Using crude EVOO phenolic extracts highly enriched in the secoiridoids oleuropein aglycon and decarboxymethyl oleuropein aglycon, we show for the first time that (1) the anticancer activity of EVOO secoiridoids is related to the activation of anti-aging/cellular stress-like gene signatures, including endoplasmic reticulum (ER) stress and the unfolded protein response, spermidine and polyamine metabolism, sirtuin-1 (SIRT1) and NRF2 signaling; (2) EVOO secoiridoids activate AMPK and suppress crucial genes involved in the Warburg effect and the self-renewal capacity of "immortal" cancer stem cells; (3) EVOO secoiridoids prevent age-related changes in the cell size, morphological heterogeneity, arrayed cell arrangement and senescence-associated ß-galactosidase staining of normal diploid human fibroblasts at the end of their proliferative lifespans. EVOO secoiridoids, which provide an effective defense against plant attack by herbivores and pathogens, are bona fide xenohormetins that are able to activate the gerosuppressor AMPK and trigger numerous resveratrol-like anti-aging transcriptomic signatures. As such, EVOO secoiridoids constitute a new family of plant-produced gerosuppressant agents that molecularly "repair" the aimless (and harmful) AMPK/mTOR-driven quasi-program that leads to aging and aging-related diseases, including cancer.

Phenolic secoiridoids in extra virgin olive oil impede fibrogenic and oncogenic epithelial-to-mesenchymal transition: extra virgin olive oil as a source of novel antiaging phytochemicals.

The epithelial-to-mesenchymal transition (EMT) genetic program is a molecular convergence point in the life-threatening progression of organ fibrosis and cancer toward organ failure and metastasis, respectively. Here, we employed the EMT process as a functional screen for testing crude natural extracts for accelerated drug development in fibrosis and cancer. Because extra virgin olive oil (EVOO) (i.e., the juice derived from the first cold pressing of the olives without any further refining process) naturally contains high levels of phenolic compounds associated with the health benefits derived from consuming an EVOO-rich Mediterranean diet, we have tested the ability of an EVOO-derived crude phenolic extract to regulate fibrogenic and oncogenic EMT in vitro. High-performance liquid chromatography (HPLC) coupled to time-of-flight (TOF) mass spectrometry assays revealed that the EVOO phenolic extract was mainly composed (∼70%) of two members of the secoiridoid family of complex polyphenols, namely oleuropein aglycone-the bitter principle of olives-and its derivative decarboxymethyl oleuropein aglycone. EVOO secoiridoids efficiently prevented loss of proteins associated with polarized epithelial phenotype (i.e., E-cadherin) as well as de novo synthesis of proteins associated with mesenchymal migratory morphology of transitioning cells (i.e., vimentin). The ability of EVOO to impede transforming growth factor-ß (TGF-ß)-induced disintegration of E-cadherin-mediated cell-cell contacts apparently occurred as a consequence of the ability of EVOO phenolics to prevent the upregulation of SMAD4-a critical mediator of TGF-ß signaling-and of the SMAD transcriptional cofactor SNAIL2 (Slug)-a well-recognized epithelial repressor. Indeed, EVOO phenolics efficiently prevented crucial TGF-ß-induced EMT transcriptional events, including upregulation of SNAI2, TCF4, VIM (Vimentin), FN (fibronectin), and SERPINE1 genes. While awaiting a better mechanistic understanding of how EVOO phenolics molecularly shut down the EMT differentiation process, it seems reasonable to suggest that nontoxic Oleaceae secoiridoids certainly merit to be considered for aging studies and, perhaps, for ulterior design of more pharmacologically active second-generation anti-EMT molecules.

Repositioning chloroquine and metformin to eliminate cancer stem cell traits in pre-malignant lesions.

Ideal oncology drugs would be curative after a short treatment course if they could eliminate epithelium-originated carcinomas at their non-invasive, pre-malignant stages. Such ideal molecules, which are expected to molecularly abrogate all the instrumental mechanisms acquired by migrating cancer stem cells (CSCs) to by-pass tumour suppressor barriers, might already exist. We here illustrate how system biology strategies for repositioning existing FDA-approved drugs may accelerate our therapeutic capacity to eliminate CSC traits in pre-invasive intraepithelial neoplasias. First, we describe a signalling network signature that overrides bioenergetics stress- and oncogene-induced senescence (OIS) phenomena in CSCs residing at pre-invasive lesions. Second, we functionally map the anti-malarial chloroquine and the anti-diabetic metformin ("old drugs") to their recently recognized CSC targets ("new uses") within the network. By discussing the preclinical efficacy of chloroquine and metformin to inhibiting the genesis and self-renewal of CSCs we finally underscore the expected translational impact of the "old drugs-new uses" repurposing strategy to open a new CSC-targeted chemoprevention era.

Crude phenolic extracts from extra virgin olive oil circumvent de novo breast cancer resistance to HER1/HER2-targeting drugs by inducing GADD45-sensed cellular stress, G2/M arrest and hyperacetylation of Histone H3.

Characterization of the molecular function of complex phenols naturally present in extra virgin olive oil (EVOO) against the HER2-gene amplified JIMT-1 cell line, a unique breast cancer model that inherently exhibits cross-resistance to multiple HER1/2-targeted drugs including trastuzumab, gefitinib, erlotinib and lapatinib, may underscore innovative cancer molecules with novel therapeutic targets because they should efficiently circumvent de novo resistance to HER1/2 inhibitors in order to elicit tumoricidal effects. We identified pivotal signaling pathways associated with the efficacy of crude phenolic extracts (PEs) obtained from 14 monovarietals of Spanish EVOOs. i) MTT-based cell viability and HPLC coupled to time-of-flight (TOF) mass spectrometry assays revealed that anti-cancer activity of EVOO PEs positively correlated with the phenolic index (i.e., total content of phenolics) and with a higher presence of the complex polyphenols secoiridoids instead of lignans. ii) Genome-wide analyses using 44 K Agilent's whole human arrays followed by Gene Set Enrichment Analysis (GSEA)-based screening of the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database revealed a differential modulation of the JIMT-1 transcriptome at the level of the cell cycle and p53 pathways. EVOO PEs differentially impacted the expression status of stress-sensing, G2-M check-point-related GADD45 genes and of p53-related CDKN1A, CDKN1C and PMAIP-1 genes. iii) Cell cycle and fluorescence microscopy analyses confirmed that secoiridoid-rich EVOO PE inhibited mitosis to promote G2-M cell cycle arrest. This was accompanied with the appearance of diffuse, even DNA staining with γH2AX and pan-nuclear hyperacetylation of Histone H3 at Lysine 18. iv) Semi-quantitative Signaling Node Multi-Target ELISAs determined that secoiridoid-rich EVOO PE drastically activated the mitogen-activated protein kinases MEK1 and p38 MAPK, a GADD45-related kinase involved in Histone H3 acetylation. Secoiridoids, a family of complex polyphenols characteristic of Oleaceae plants, appear to permit histones to remain in hyperacetylated states and through the resulting alterations in gene regulation to reduce mitotic viability and metabolic competence of breast cancer cells inherently refractory to HER-targeting therapies ab initio. Oleaceae secoiridoids could provide a valuable phytochemical platform for the design of more pharmacologically active second-generation phytopharmaceutical anti-breast cancer molecules with a unique mode of action.

Characterization and quantification of phenolic compounds of extra-virgin olive oils with anticancer properties by a rapid and resolutive LC-ESI-TOF MS method.

The characterization and quantification of extra-virgin olive oil (EVOO) phenolic compounds by a rapid resolution liquid chromatography (RRLC) method coupled to diode-array and time of flight mass spectrometry (TOF) detection systems was developed. The RRLC method transferred from a conventional HPLC one achieved better performance with shorter analysis times. The phenolic compounds were separated with a C18 column (150 mm x 4.6mm, 1.8 microm) using water with 0.5% acetic acid and acetonitrile as mobile phases. Good peak resolution was obtained and 19 different phenols were identified in less than 20 min providing a new level of information about the samples in shorter time. The applicability of this analytical approach was confirmed by the successful analysis of three different EVOO varieties (Picual, Hojiblanca, and Arbequina) obtained from different trademarks. Besides identification of the most important phenolic compounds and their quantification in three different ways (RRLC-UV, RRLC-MS and a new approach using the total polyphenol content obtained with Folin Ciocalteau, the relative areas and the response factors), we also described the occurrence of correlations between the phenolic composition of EVOO-derived crude phenolic extracts and their anti-proliferative abilities toward human breast cancer-derived cell lines. When compared with lignans-rich EVOO varieties, secoiridoids-rich EVOO had a significantly strong ability to alter cell viability in four different types of human breast carcinoma cells.

A 2-D-HPLC-CE platform coupled to ESI-TOF-MS to characterize the phenolic fraction in olive oil.

A 2-D-HPLC/CE method was developed to separate and characterize more in depth the phenolic fraction of olive oil samples. The method involves the use of semi-preparative HPLC (C18 column 250x10 mm, 5 microm) as a first dimension of separation to isolate phenolic fractions from commercial extra-virgin olive oils and CE coupled to TOF-MS (CE-TOF-MS) as a second dimension, to analyze the composition of the isolated fractions. Using this method, a large number of compounds were tentatively identified, some of them by first time, based on the information concerning high mass accuracy and the isotopic pattern provided by TOF-MS analyzer together with the chemical knowledge and the behavior of the compounds in HPLC and CE. From these results it can be concluded that 2-D-HPLC-CE-MS provides enough resolving power to separate hundreds of compounds from highly complex samples, such as olive oil. Furthermore, in this paper, the isolated phenolic fractions have been used for two specific applications: quantification of some components of extra-virgin olive oil samples in terms of pure fractions, and in vitro studies of its anti-carcinogenic capacity.

Extra-virgin olive oil polyphenols inhibit HER2 (erbB-2)-induced malignant transformation in human breast epithelial cells: relationship between the chemical structures of extra-virgin olive oil secoiridoids and lignans and their inhibitory activities on the tyrosine kinase activity of HER2.

Depending on their structure, some polyphenols (e.g. flavonoids) abundantly found in plant-derived beverages such as green tea can efficiently inhibit tyrosine kinase and serine/threonine kinase activities. Extra-virgin olive oil (EVOO - the juice of the olive obtained solely by pressing and consumed without any further refining process) is unique among other vegetable oils because of the high level of naturally occurring phenolic compounds. We explored the ability of EVOO polyphenols to modulate HER2 tyrosine kinase receptor-induced in vitro transformed phenotype in human breast epithelial cells. Using MCF10A normal breast epithelial cells retrovirally engineered to overexpress the wild-type sequence of human HER2, we further determined the relationship between chemical structures of EVOO-derived phenolics and their inhibitory activities on the tyrosine kinase activity of the HER2 oncoprotein. When the activation (phosphorylation) status of HER2 was semi-quantitatively measured the secoiridoids blocked HER2 signaling by rapidly reducing the activation status of the 1248 tyrosine residue (Y1248), the main autophosphorylation site of HER2. EVOO-derived single phenols tyrosol and hydroxytyrosol and the phenolic acid elenolic acid failed to significantly decrease HER2 tyrosine kinase activity. The anti-HER2 tyrosine kinase activity IC50 values were up to 5-times lower in the presence of EVOO-derived lignans and secoiridoids than in the presence of EVOO-derived single phenols and phenolic acids. EVOO polyphenols induced strong tumoricidal effects by selectively triggering high levels of apoptotic cell death in HER2-positive MCF10A/HER2 cells but not in MCF10A/pBABE matched control cells. EVOO lignans and secoiridoids prevented HER2-induced in vitro transformed phenotype as they inhibited colony formation of MCF10A/HER2 cells in soft-agar. Our current findings not only molecularly support recent epidemiological evidence revealing that EVOO-related anti-breast cancer effects primarily affect the occurrence of breast tumors over-expressing the type I receptor tyrosine kinase HER2 but further suggest that the stereochemistry of EVOO-derived lignans and secoiridoids might provide an excellent and safe platform for the design of new HER2 targeted anti-breast cancer drugs.

tabAnti-HER2 (erbB-2) oncogene effects of phenolic compounds directly isolated from commercial Extra-Virgin Olive Oil (EVOO).

BACKGROUND: The effects of the olive oil-rich Mediterranean diet on breast cancer risk might be underestimated when HER2 (ERBB2) oncogene-positive and HER2-negative breast carcinomas are considered together. We here investigated the anti-HER2 effects of phenolic fractions directly extracted from Extra Virgin Olive Oil (EVOO) in cultured human breast cancer cell lines. METHODS: Solid phase extraction followed by semi-preparative high-performance liquid chromatography (HPLC) was used to isolate phenolic fractions from commercial EVOO. Analytical capillary electrophoresis coupled to mass spectrometry was performed to check for the composition and to confirm the identity of the isolated fractions. EVOO polyphenolic fractions were tested on their tumoricidal ability against HER2-negative and HER2-positive breast cancer in vitro models using MTT, crystal violet staining, and Cell Death ELISA assays. The effects of EVOO polyphenolic fractions on the expression and activation status of HER2 oncoprotein were evaluated using HER2-specific ELISAs and immunoblotting procedures, respectively. RESULTS: Among the fractions mainly containing the single phenols hydroxytyrosol and tyrosol, the polyphenol acid elenolic acid, the lignans (+)-pinoresinol and 1-(+)-acetoxypinoresinol, and the secoiridoids deacetoxy oleuropein aglycone, ligstroside aglycone, and oleuropein aglycone, all the major EVOO polyphenols (i.e. secoiridoids and lignans) were found to induce strong tumoricidal effects within a micromolar range by selectively triggering high levels of apoptotic cell death in HER2-overexpressors. Small interfering RNA-induced depletion of HER2 protein and lapatinib-induced blockade of HER2 tyrosine kinase activity both significantly prevented EVOO polyphenols-induced cytotoxicity. EVOO polyphenols drastically depleted HER2 protein and reduced HER2 tyrosine autophosphorylation in a dose- and time-dependent manner. EVOO polyphenols-induced HER2 downregulation occurred regardless the molecular mechanism contributing to HER2 overexpression (i.e. naturally by gene amplification and ectopically driven by a viral promoter). Pre-treatment with the proteasome inhibitor MG132 prevented EVOO polyphenols-induced HER2 depletion. CONCLUSION: The ability of EVOO-derived polyphenols to inhibit HER2 activity by promoting the proteasomal degradation of the HER2 protein itself, together with the fact that humans have safely been ingesting secoiridoids and lignans as long as they have been consuming olives and OO, support the notion that the stereochemistry of these phytochemicals might provide an excellent and safe platform for the design of new HER2-targeting agents.

Analyzing effects of extra-virgin olive oil polyphenols on breast cancer-associated fatty acid synthase protein expression using reverse-phase protein microarrays.

Inhibitors of fatty acid synthase (FASN), a key enzyme involved in the anabolic conversion of dietary carbohydrates to fat in mammals, are receiving increasingly more attention as they may provide therapeutic moieties for the treatment of human malignancies. Natural compounds, such as the green tea polyphenol epigallocatechin-3-gallate, have been shown to induce anti-cancer effects by suppressing FASN, which may account for the epidemiologically observed inverse correlation between green-tea drinking and cancer risk in Oriental populations. Since extra-virgin olive oil (EVOO)-derived phenolics have been suggested to possess biological activities that may explain the health-promoting effects of the 'Mediterranean diet', we evaluated their effects on the expression of FASN protein in human breast epithelial cell lines. First, we developed a reverse phase protein microspot array (RPPA) capable of rapidly assessing the relative amount of FASN protein in whole lysates from cultured human cells. Then we tested the effects of phenolic fractions from EVOO and its main constituents including single phenols (i.e. tyrosol, hydroxytyrosol, vanillin), phenolic acids (i.e. caffeic acid, p-coumaric acid, vanillic acid, ferulic acid, elenolic acid), lignans (i.e. 1-[+]-pinoresinol, 1-[+]-acetoxy-pinoresinol), flavonoids (i.e. apigenin, luteolin), or secoiridoids (i.e. deacetoxyoleuropein aglycone, ligstroside aglycone, oleuropein glycoside, oleuropein aglycone) on FASN protein expression. EVOO polyphenols lignans, flavonoids and secoiridoids were found to drastically suppress FASN protein expression in HER2 gene-amplified SKBR3 breast cancer cells. Equivalent results were observed in MCF-7 cells engineered to overexpress the HER2 tyrosine kinase receptor, a well-characterized up-regulator of FASN expression in aggressive sub-types of cancer cells. EVOO-derived lignans, flavonoids and secoiridoids were significantly more effective than the mono-HER2 inhibitor trastuzumab ( approximately 50% reduction) and as effective as the dual HER1/HER2 tyrosine kinase inhibitor lapatinib (> or =95% reduction) at suppressing high-levels of FASN protein in HER2-overexpressing SKBR3 and MCF-7/HER2 cells. EVOO single phenols and phenolic acids failed to modulate FASN expression in SKBR3 and MCF-7/HER2 cells. These findings reveal for the first time that phenolic fractions, directly extracted from EVOO, may induce anti-cancer effects by suppressing the expression of the lipogenic enzyme FASN in HER2-overexpressing breast carcinoma cells, thus offering a previously unrecognized mechanism for EVOO-related cancer preventive effects.

Olive oil's bitter principle reverses acquired autoresistance to trastuzumab (Herceptin) in HER2-overexpressing breast cancer cells.

BACKGROUND: A low incidence of breast cancer in the Mediterranean basin suggests that a high consumption of Extra Virgin Olive Oil (EVOO) might confer this benefit. While the anti-HER2 oncogene effects of the main omega-9 fatty acid present in EVOO triacylglycerols (i.e., oleic acid) have been recently described, the anti-breast cancer activities of EVOO non-glyceridic constituents--which consist of at least 30 phenolic compounds--remained to be evaluated. METHODS: Semi-preparative HPLC was used to isolate EVOO polyphenols (i.e., tyrosol, hydroxytyrosol, oleuropein). Both the anti-proliferative and the pro-apoptotic effects of EVOO phenolics were evaluated by using MTT-based quantification of metabolically viable cells and ELISA-based detection of histone-associated DNA fragments, respectively. The nature of the interaction between oleuropein aglycone and the anti-HER2 monoclonal antibody trastuzumab (Herceptin) was mathematically evaluated by the dose-oriented isobologram technique. HER2-specific ELISAs were employed to quantitatively assess both the basal cleavage of the HER2 extracellular domain (ECD) and the expression level of total HER2. The activation status of HER2 was evaluated by immunoblotting procedures using a monoclonal antibody specifically recognizing the tyrosine phosphorylated (Phosphor-Tyr1248) form of HER2. RESULTS: Among EVOO polyphenols tested, oleuropein aglycone was the most potent EVOO phenolic in decreasing breast cancer cell viability. HER2 gene-amplified SKBR3 cells were ~5-times more sensitive to oleuropein aglycone than HER2-negative MCF-7 cells. Retroviral infection of the HER2 oncogene in MCF-7 cells resulted in a "SKBR3-assimilated" phenotype of hypersensitivity to oleuropein aglycone. An up to 50-fold increase in the efficacy of trastuzumab occurred in the presence of oleuropein aglycone. A preclinical model of acquired autoresistance to trastuzumab (SKBR3/Tzb100 cells) completely recovered trastuzumab sensitivity (> 1,000-fold sensitization) when co-cultured in the presence of oleuropein aglycone. Indeed, the nature of the interaction between oleuropein aglycone and trastuzumab was found to be strongly synergistic in Tzb-resistant SKBR3/Tzb100 cells. Mechanistically, oleuropein aglycone treatment significantly reduced HER2 ECD cleavage and subsequent HER2 auto-phosphorylation, while it dramatically enhanced Tzb-induced down-regulation of HER2 expression. CONCLUSION: Olive oil's bitter principle (i.e., oleuropein aglycone) is among the first examples of how selected nutrients from an EVOO-rich "Mediterranean diet" directly regulate HER2-driven breast cancer disease.

HER2 (erbB-2)-targeted effects of the omega-3 polyunsaturated fatty acid, alpha-linolenic acid (ALA; 18:3n-3), in breast cancer cells: the "fat features" of the "Mediterranean diet" as an "anti-HER2 cocktail".

BACKGROUND: Data derived from epidemiological and experimental studies suggest that alphalinolenic acid (ALA; 18:3n-3), the main omega-3 polyunsaturated fatty acid (PUFA) present in the Western diet, may have protective effects in breast cancer risk and metastatic progression. A recent pilot clinical trial assessing the effects of ALA-rich dietary flaxseed on tumor biological markers in postmenopausal patients with primary breast cancer demonstrated significant reductions in tumor growth and in HER2 (erbB-2) oncogene expression. HYPOTHESIS: The molecular mechanism by which ALA inhibits breast cancer cell growth and metastasis formation may involve a direct regulation of HER2, a well-characterized oncogene playing a key role in the etiology, progression and response to some chemo- and endocrine therapies in approximately 20% of breast carcinomas. METHODS: Using HER2-specific ELISA, flow cytometry, immunofluorescence microscopy, Western blotting, RT-PCR and HER2 promoter-reporter analyses, we characterized the effects of exogenous supplementation with ALA on the expression of HER2 oncogene, a master key player in the onset and metastasis formation of breast cancer disease. Metabolic status (MTT) assays were performed to evaluate the nature of the cytotoxic interaction between ALA and the humanized anti-HER2 monoclonal antibody trastuzumab (Herceptin). To study these issues we used BT-474 and SKBr-3 breast cancer cells, which naturally exhibit amplification of the HER2 oncogene. RESULTS: ALA treatment dramatically suppressed the expression of HER2-coded p185Her-2/neu oncoprotein as determined by ELISA, flow cytometry, immunofluorescence microscopy and immunoblotting techniques. Interestingly, ALA-induced down-regulation of p185Her-2/neu correlated with a transcriptional response as no HER2 mRNA signal could be detected by RT-PCR upon treatment with optimal concentrations of ALA (up to 20 microM). Consistent with these findings, ALA exposure was found to dramatically repress the activity of a Luciferase reporter gene driven by the HER2 promoter. Moreover, the nature of the cytotoxic interaction between ALA and trastuzumab (Herceptin) revealed a significant synergism as assessed by MTT-based cell viability assays. CONCLUSIONS: i) These findings reveal that the omega-3 PUFA ALA suppresses overexpression of HER2 oncogene at the transcriptional level, which, in turn, interacts synergistically with anti-HER2 trastuzumab- based immunotherapy. ii) Our results molecularly support a recent randomized double-blind placebo-controlled clinical trial suggesting that ALA may be a potential dietary alternative or adjunct to currently used drugs in the management of HER2-positive breast carcinomas. iii) Considering our previous findings demonstrating the <> of the omega-6 PUFA linolenic acid (LA; 18:2n-6) and the <> of the omega-3 PUFA docosahexaenoic acid (DHA; 22:6n-3) and of the omega-9 monounsaturated fatty acid oleic acid (OA; 18:1n-9), it is reasonable to suggest that a low omega-6/omega-3 PUFA ratio and elevated MUFA levels, the two prominent <> of the <>, should be extremely efficient at blocking HER2 expression in breast cancer cells.