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To distinguish various types of local recurrence after conserving treatment of breast cancer and to evaluate their predictive value.We first researched the pronostic factors after local recurrence and second evaluated the predictive factors of skin and inflammatory recurrences out of a series of 605 cases of stage I and stage II breast cancer of less than 4 cm in diameter that occurred after conserving treatment.Multivariate analysis revealed two major predictors of poor prognosis associated with recurrence: early appearance Hazard ratio 3.0 (1.28-7.00) (p = 0.011) and inflammatory or skin involvement Hazard ratio 3.38 (1.36-8.45) (p = 0.009). A local recurrence multiplied the relative risk for metastasis by 2.6. This result depended on the type of recurrence: when those with inflammatory and cutaneous types were excluded, local recurrence was no longer a poor prognostic factor. Patients who experienced primary invasive tumor with histologic multifocality have a 4.08 (1.44-11.59) (p0.004) times greater risk of developing cutaneous or inflammatory recurrences compared with patients who experienced breast cancer unique localization.As histologic multifocality is the only factor predictive of dark prognosis local breast cancer recurrences, aggressive therapy at the time of the primary treatment could be the therapeutic implications of such finding on the original tumor.

Data derived from experimental studies suggest that alpha-linolenic acid may have a protective effect in breast cancer. Observations obtained from epidemiological studies have not allowed conclusions to be drawn about a potential protective effect of dietary alpha-linolenic acid on breast cancer, possibly because of methodological issues. This case-control study conducted in an homogeneous population from a central area in France was designed to explore the hypothesis that alpha-linolenic acid inhibits breast cancer, using fatty acid levels in adipose breast tissue as a biomarker of past qualitative dietary intake of fatty acids. Biopsies of adipose breast tissue at the time of diagnosis were obtained from 123 women with invasive non-metastatic breast carcinoma. 59 women with benign breast disease served as controls. Individual fatty acids were analysed by capillary gas chromatography. An unconditional logistic regression model was used to obtain odds ratio estimates whilst adjusting for age, menopausal status and body mass index (BMI). No association was found between fatty acids (saturates, monounsaturates, long-chain polyunsaturates n-6 or n-3) and the disease, except for alpha-linolenic acid which showed an inverse association with the risk of breast cancer. The relative risk of breast cancer for women in the highest quartile of adipose breast tissue alpha-linolenic acid level was 0.36 (95% confidence interval=0.12-1.02) compared with those in the lowest quartile (P trend=0.026), suggesting a protective effect of alpha-linolenic acid in the risk of breast cancer. The effects of dietary alpha-linolenic on the risk of breast cancer warrant further study.

L’alimentation intervient a differents niveaux dans le deroulement de la maladie cancereuse : au niveau du risque [1] et au niveau de l’evolution en modifiant le risque de survenue des metastases. L’alimentation influence-t-elle aussi la reponse aux traitements anticancereux ? A l’appui de cette hypothese viennent deux observations indirectes realisees dans le cancer du sein : nos donnees [2, 3] ainsi que les observations epidemiologiques provenant d’autres travaux [4] ont apporte des arguments supportant l’hypothese que les lipides alimentaires peuvent influencer la reponse des tumeurs mammaires aux traitements. On sait que la composition des lipides membranaires n’est pas genetiquement determinee, mais qu’elle depend des acides gras disponibles aux tissus peripheriques. Le type d’acides gras disponibles est influence par les apports alimentaires. Comme les tumeurs incorporent dans leurs lipides les acides gras disponibles de facon similaire aux autres tissus [5], il est plausible que les habitudes alimentaires (apports alimentaires en acides gras polyinsatures, vitamines anti ou pro-oxydantes) puissent influencer leur chimiosensibilite en apportant aux cellules tumorales des substrats de peroxydation.

To investigate whether the oxidative status of an 18:3(n-3) polyunsaturated fatty acid (PUFA)-enriched diet could modulate the growth of chemically induced rat mammary tumors, three independent experiments were performed. Experiments I and II examined the variation of tumor growth by addition of antioxidant (vitamin E) or a prooxidant system (sodium ascorbate/2-methyl-1,4-naphthoquinone) to a 15% linseed oil diet rich in 18:3(n-3). Experiment III addressed the role of PUFA in the tumor growth modulation by vitamin E. For this purpose, we compared the effect of vitamin E in 15% fat diets containing a high level of 18:3(n-3) (linseed oil, high-PUFA diet) or devoid of 18:3(n-3) (hydrogenated palm/sunflower oil, low-PUFA diet). In Experiments I-III, tumor growth increased in the presence of vitamin E compared with control (without vitamin E). Furthermore, it decreased when prooxidant was added. In contrast, no difference was observed when the diet was low in PUFA, suggesting that sensitivity of PUFA to peroxidation may interfere with tumor growth. This observation was supported by growth kinetic parameter analysis, which indicated that tumor growth resulted from variations in cell loss but not from changes in cell proliferation. These data show that, in vivo, PUFA effects on tumor growth are highly dependent on diet oxidative status.

En France, comme dans la plupart des pays occidentaux, le cancer du sein est la première cause de mortalité, avec un nombre annuel de décès proche de 10 000. Chez les femmes, le cancer du sein est celui dont le taux d’incidence est le plus élevé dans la plupart des pays occidentaux. En France, il y a approximativement 35 000 nouveaux cas chaque année. Le taux d’incidence est de 80 pour 100 000 femmes/an. Il existe une disparité géographique dans les taux d’incidence du cancer du sein. Ils sont élevés dans tous les pays développés, à l’exception du Japon et de la Chine. Ajusté sur l’âge, il est le plus élevé aux États-Unis, et le plus bas en Chine, en Inde, au Japon. La France se situe à une position intermédiaire en Europe. L’incidence du cancer du sein est globalement plus faible dans les pays du Sud de l’Europe. Cette disparité géographique ne peut pas être expliquée uniquement par les facteurs génétiques. L’étude des populations migrantes, dont les taux d’incidence du cancer du sein se modifient pour atteindre celui du pays dans lequel elles migrent, a permis de mettre en évidence le rôle des facteurs environnementaux dans l’apparition du cancer du sein. Parmi ceux-là, la part de l’alimentation est estimée à environ 35 % (entre 20 à 60 %, en fonction du site du cancer) [1]. Il existe donc un réel potentiel de prévention du cancer du sein, sous réserve que les aliments protecteurs soient mis en évidence et que les nutriments responsables de ces effets protecteurs soient individualisés.

Exogenous polyunsaturated fatty acids modulate the cytotoxic activity of anti-cancer drugs. In this study, we examined whether lipid peroxidation is a potential mechanism through which fatty acids enhance drug cytotoxicity. We measured cell viability in the human breast cancer cell line MDA-MB-231 exposed to doxorubicin in the presence of non-cytotoxic concentrations of various polyunsaturated fatty acids for 6 days. To determine the role of lipid peroxidation, the hydroperoxide level was measured in cell extracts. Among all polyunsaturated fatty acids tested, docosahexaenoic acid (DHA, 22:6n-3) was the most potent in increasing doxorubicin cytotoxicity: cell viability decreased from 54% in the presence of 10(-7) M doxorubicin alone to 21% when cells were incubated with doxorubicin and DHA. After addition of an oxidant system (sodium ascorbate/2-methyl-1,4-naphthoquinone) to cells incubated with doxorubicin and DHA, cell viability further decreased to 12%. Cell hydroperoxides increased commensurately. The effect of DHA on doxorubicin activity and lipid hydroperoxide formation was abolished by a lipid peroxidation inhibitor (dl-alpha-tocopherol) or when oleic acid (a non-peroxidizable fatty acid) was used in place of DHA. No effect was observed with mitoxantrone, a drug with a low peroxidation-generating potential. Thus, DHA may increase the efficacy of oxyradical-producing drugs through a mechanism involving a generation of lipoperoxides. This may lead in vivo to a modulation of tumor cell chemosensitivity by DHA and oxidant agents.

The effects of changing the composition of membrane lipids on protein kinase C (PKC) activation were studied in MCF-7 human breast cancer cells. The supply of linoleate or α -linolenate to MCF-7 cells altered cell membranes fatty acid composition but did not affect PKC activity. When the cells were additionally exposed to IGF-1, the same fatty acids caused a dramatic increase in membrane-bound PKC activity. We also found that the mitogenic response induced by IGF-1 was not enhanced in those conditions when PKC becomes activated by linoleate and α -linolenate. These data show that these fatty acids elicit a distinct route for the transmission of IGF-1 signal by inducing the PKC pathway. They suggest that linoleate and α -linolenate could control the biological response of MCF-7 cells to IGF-1.

The SK3 channel, a potassium channel, was recently shown to control cancer cell migration, a critical step in metastasis outgrowth. Here, we report that expression of the SK3 channel was markedly associated with bone metastasis. The SK3 channel was shown to control constitutive Ca2+ entry and cancer cell migration through an interaction with the Ca2+ channel Orai1. We found that the SK3 channel triggers an association with the Orai1 channel within lipid rafts. This localization of an SK3–Orai1 complex seemed essential to control cancer cell migration. This suggests that the formation of this complex in lipid rafts is a gain-of-function, because we showed that none of the individual proteins were able to promote the complete phenotype. We identified the alkyl-lipid Ohmline as a disrupting agent for SK3–Orai1 lipid raft localization. Upon Ohmline treatment, the SK3–Orai1 complex moved away from lipid rafts, and SK3-dependent Ca2+ entry, migration, and bone metastases were subsequently impaired. The colocalization of SK3 and Orai1 in primary human tumors and bone metastases further emphasized the clinical relevance of our observations. Targeting SK3–Orai1 in lipid rafts may inaugurate innovative approaches to inhibit bone metastases. Cancer Res; 73(15); 4852–61. ©2013 AACR.

Background: Patients with recurrent/metastatic endometrial cancer that progresses after chemotherapy have limited treatment options and poor outcomes. Preclinical data suggest the oral mammalian target of rapamycin inhibitor everolimus may provide clinical benefit in these patients. Methods: In this multicenter, open-label, phase 2 study, patients with advanced or metastatic endometrial cancer refractory to one or two previous chemotherapy regimens received everolimus 10 mg per day until progression or unacceptable toxicity. Primary end point was the non-progressive disease rate at 3 months. Secondary end points included duration of response, progression-free, and overall survival (OS), and safety. Results: Forty-four patients were enrolled (median age, 65 years); 66% received one previous chemotherapy regimen. The 3-month non-progressive disease rate was 36% (95% confidence interval 22–52%), including two patients (5%) with partial response (PR). At 6 months, two additional patients experienced PR. Median duration of response was 3.1 months. Median progression-free and OS were 2.8 months and 8.1 months, respectively. The most common adverse events were anaemia (100%), fatigue (93%), hypercholesterolaemia (81%), and lymphopenia (81%). Conclusion: Everolimus demonstrated efficacy and acceptable tolerability in patients with chemotherapy-refractory advanced or metastatic endometrial cancer. These results support the further development of phosphatidylinositol 3-kinase-targeted therapies in endometrial cancer.

International audience; New ultrasound parameters, potentially predictive of tumor response to chemotherapy, were sought after analyzing details of vascular architecture of mammary tumors during chemotherapy. Tumor-bearing rats were separated into untreated or docetaxel-treated group (6 mg/kg/week). Power Doppler Index and vascular contrast-enhanced ultrasound (CEUS) reference endpoints (Peak, area under the curve (AUC), blood flow) were evaluated at the beginning (W (0)), and after 2 and 6 weeks of docetaxel treatment (W (+2) and W (+6)). An improved CEUS image analysis, taking advantage of individual pixel intensity, was developed to quantify large, medium, and small vessels of tumors. Standard immunohistochemistry validated this new methodology analyzing tumor vascular architecture. In rats, there was an enrichment of vascularization with large vessels during tumor growth indicative of a vascular adjustment to tumor size. Docetaxel stopped tumor growth, and showed a sequential effect on vascular parameters. After an initial enrichment in larger vessels (by threefold) at W (+2), docetaxel led to a diminution of vascular parameters at W (+6) (-46 % for peak, -55 % for AUC -31 % compared to W (0)) and a vascular remodeling in favor of small vessels. One of the CEUS parameters measured before chemotherapy, the so-called global contrast-enhanced pixels density, was predictive of rat tumor response to treatment (r = 0.80; p < 0.01). The method was then applied in a clinical setting to detect changes of vascular architecture during chemotherapy of human breast carcinoma. The docetaxel chemotherapy of breast carcinomas induced a similar sequential effect, with vessel enlargement after two cycles of docetaxel treatment and an antiangiogenic effect after six cycles. Such vascular remodeling was not noticed when patients were treated with 5-fluorouracil-epirubicin-cyclophosphamide. Taken together, the sharpened analysis of CEUS pixel intensity presented here strengthened the monitoring of breast tumor vasculature with the potential to improve the prediction of docetaxel efficacy.

International audience; Many studies have reported changes in potassium channel expression in many cancers and the involvement of these channels in various stages of cancer progression. By contrast, data concerning SKCa channels (small conductance calcium-activated potassium channels) have only recently become available. This review aims i) to present the structure and physiology of SKCa channels, ii) to provide an overview of published data concerning the SKCa proteins produced in tumor cells, and, whenever possible, the biological function assigned to them and iii) to review previous and novel modulators of SKCa channels. SKCa channels are activated by low concentrations of intracellular calcium and consist of homo- or heteromeric assemblies of α-subunits named SK1, SK2 and SK3. SK2-3 channels are expressed in tumors and have been assigned a biological function in cancer cells: the enhancement of cell proliferation and cell migration by hijacking the functions of SK2 and SK3 channels, respectively. Two major classes of SKCa modulators have been described: toxins (apamin) and small synthetic molecules. Most SKCa blockers are pore blockers, but some modify the calcium sensitivity of SKCa channels without interacting with the apamin binding site. In this review, we present edelfosine and ohmline as atypical anticancer agents and novel SK3 inhibitors. Edelfosine and ohmline are synthetic alkyl-lipids with structures different from all previously described SKCa modulators. They should pave the way for the development of a new class of migration-targeted anticancer agents. We believe that such blockers have potential for use in the prevention or treatment of metastasis.

International audience; The aim of this study was to determine how n-3 polyunsaturated fatty acid (PUFAs) counteracted tumor chemoresistance by restoring a functional vascularization. Rats with chemically induced mammary tumors were divided into two nutritional groups: a control group and a group fed with an n-3 PUFA-enriched diet. Both groups were treated with docetaxel. Functional vascular parameters (ultrasounds, interstitial fluid pressure) were determined for both nutritional groups before (W(0)) and during docetaxel treatment [every 2 h up to 1 week (W(+1)) for interstitial fluid pressure, at W(+1) for Evans blue extravasation and at W(+2) and W(+6) for ultrasounds]. In vitro n-3 PUFA-induced changes in endothelial cell migration, permeability and phosphorylation of endothelial nitric oxide synthase were evaluated using human umbilical vein endothelial cells. Whereas docetaxel stabilized tumor growth in the rat control group, it induced a 50% tumor regression in the n-3 PUFA group. Ultrasounds parameters were consistently lower in the n-3 PUFA group at all time points measured, down to ∼50% at W(+6). A single dose of docetaxel in the n-3 PUFA group markedly reduced interstitial fluid pressure from 2 h after injection up to W(+1) when Evans blue extravasation was increased by 3-fold. A decreased activation of endothelial nitric oxide synthase in tumors of the n-3 PUFA group, and in human umbilical vein endothelial cell cultured with n-3 PUFA, points toward a PUFA-induced disruption of nitric oxide signaling pathway. This normalization of tumor vasculature functions under n-3 PUFA diet indicates that such a supplementation, by improving drug delivery in mammary tumors, could be a complementary clinical strategy to decrease anticancer drug resistance.

International audience; Edelfosine is an inhibitor of SK3 channel-mediated cell migration. However, this compound bears adverse in vivo side effects. Using cell SK3 dependent cell-migration assay, patch-clamp, 125I-apamin binding, and in vivo experiments we tested the ability of 15 lipid derivatives with chemical structures inspired from edelfosine to inhibit SK3 channels. Using a structure-activity relationship approach we identified an edelfosine analog named Ohmline (1-O-hexadecyl-2-O-methyl-sn-glycero-3-lactose) with potent inhibitory effects on the SK3 channel. Its potency was greater for SK3 channels than for SK1 channels; it did not affect IKCa channels and only slightly but not significantly affected SK2 channels. This is the first SKCa channel blocker that can be used to discriminate between SK2 and SK1/SK3 channels and represents a useful tool to investigate the functional role of SK3 channels in peripheral tissues (that do not express SK1 channels). This compound, which acts with an IC50 of 300 nM, did not displace apamine from SKCa channels and had no effect on non-specific edelfosine targets such as protein kinase C (PKC), receptors for platelet activating factor (PAF) and lysophosphatidic acid (LPA), as well as non-cancerous cells. This is promising because the pitfalls associated with the use of edelfosine-like compounds have been that their effective and high concentrations are often cytotoxic due to their detergent-like character causing normal cell lysis. Finally, Ohmline reduced metastasis development in a mice model of tumor indicating that this compound could become a lead compound for the first class of lipid-antimetastatic agent.

International audience; Edelfosine is an inhibitor of SK3 channel – mediated cell migration. However, this compound bears adverse in vivo side effects. Using cell SK3 dependent cell-migration assay, patch-clamp, 125I-apamin binding, and in vivo experiments we tested the ability of 15 lipid derivatives with chemical structures inspired from edelfosine to inhibit SK3 channels. Using a structure-activity relationship approach we identified an edelfosine analog named Ohmline (1-O-hexadecyl- 2-O-methyl-sn-glycero-3-lactose) with potent inhibitory effects on the SK3 channel. Its potency was greater for SK3 channels than for SK1 channels; it did not affect IKCa channels and only slightly but not significantly affected SK2 channels. This is the first SKCa channel blocker that can be used to discriminate between SK2 and SK1/SK3 channels and represents a useful tool to investigate the functional role of SK3 channels in peripheral tissues (that do not express SK1 channels). This compound, which acts with an IC50 of 300 nM, did not displace apamin from SKCa channels and had no effect on non-specific edelfosine targets such as protein kinase C (PKC), receptors for platelet activating factor (PAF) and lysophosphatidic acid (LPA), as well as non-cancerous cells. This is promising because the pitfalls associated with the use of edelfosine-like compounds have been that their effective and high concentrations are often cytotoxic due to their detergent-like character causing normal cell lysis. Finally, Ohmline reduced metastasis development in a mice model of tumor indicating that this compound could become a lead compound for the first class of lipid-antimetastatic agent.

International audience; Background & aims: Cancer cachexia is a dynamic process characterized by a negative energy balance induced by anorexia and hypermetabolism. The mechanisms leading to hypermetabolism are not totally elucidated. This study examines the efficiency of oxidative phosphorylation and energy wasting in liver mitochondria isolated from rats with cancer cachexia induced by peritoneal carcinosis (PC).Methods: PC was generated by an intraperitoneal injection of cancer cells (PROb) in BDIX rats. The efficiency of oxidative phosphorylation and energy wasting as well as the role played by reactive oxygen species (ROS) and cardiolipin (mitochondrial inner membrane phospholipid) in these processes were assessed in liver mitochondria of PC and pair-fed control rats.Results: The efficiency of oxidative phosphorylation decreased (-26%) while energy wasting increased (+22%) in liver mitochondria from PC compared to control rats. The increased energy wasting was associated with a higher cardiolipin content (+55%, p

Cancers are among the leading causes of death worldwide. Voltage-gated sodium channels, among other ion channels, appear as new molecular players in epithelial cancers. Highly metastatic breast cancer cells express Na(V)1.5, the main isoform expressed in cardiac cells, where the current generated by the flux of sodium ions is responsible for the excitability. Breast cancer cells are not excitable and the protein activity regulates cell invasiveness, through the modulation of activity of acidic cathepsins, a characteristic involved in the metastatic phenotype. Interestingly, it is known that ω-3 LC-PUFA can exert beneficial effects by preventing post-myocardial infarction arrhythmias and by reducing the incidence of metastatic breast cancer. In this review, we compare the effects of some ω-3 LC-PUFA on Na(V)1.5 expressed in both cardiac and MDA-MB-231 breast cancer cells. We propose that some of the effects of ω-3 LC-PUFA act through common mechanisms involved in both diseases.

International audience; Docosahexaenoic acid (DHA), upon incorporation into tumor tissue, has the potential to sensitize tumors to the effects of chemotherapy or radiation therapy. Although DHA has usually been supplied to tumor tissue in the diet, appropriate dietary conditions required to obtain optimal tumor levels have not been established. Hence, we studied mammary tumor tissue responses in rats fed various durations and doses of DHA. Rats fed a palm oil enriched diet (diet 0) were switched to diets providing either 0.8 g DHA/day (diet 1) or 1.5 g DHA/day (diet 2). Tumor tissue fatty acid composition was analysed at baseline (diet 0), at weeks 1, 4 and 9 during diet 1 and at week 4 during diet 2. Dietary DHA supplementation differentially increased DHA within phospholipids (PL) and triacylglycerol (TAG) fractions in tumors. DHA level equilibrated between 2 and 4 weeks in PL while DHA increase was more progressive in TAG and did not reach a steady state. A higher dose of DHA further increased DHA content in tumor PL and TAG (P = 0.018 and P < 0.001, respectively). DHA concentration in plasma PL was positively correlated with DHA in tumor PL (r = 0.72; P = 0.0003) and TAG (r = 0.64; P = 0.003). We conclude that dietary DHA supplementation enhances tumor content of DHA in a time- and dose-dependent manner, and that the DHA level in plasma PL could be used as a proxy for tumor DHA. These findings have implications for dietary DHA supplementations in cancer patients.

Because triacylglycerol (TAG) structure influences the metabolic fate of its component fatty acids, we have examined human colostrum and mature milk TAG with particular attention to the location of the very long chain polyunsaturated fatty acid on the glycerol backbone. The analysis was based on the formation of various diacylglycerol species from human milk TAG upon chemical (Grignard degradation) or enzymatic degradation. The structure of the TAG was subsequently deduced from data obtained by gas chromatographic analysis of the fatty acid methyl esters in the diacylglycerol subfractions. The highly specific TAG structure observed was identical in mature milk and colostrum. The three major fatty acids (oleic, palmitic and linoleic acids) each showed a specific preference for a particular position within milk TAG: oleic acid for the sn-1 position, palmitic acid for the sn-2 position and linoleic acid for the sn-3 position. Linoleic and alpha-linolenic acids exhibited the same pattern of distribution and they were both found primarily in the sn-3 (50%) and sn-1 (30%) positions. Their longer chain analogs, arachidonic and docosahexaenoic acids, were located in the sn-2 and sn-3 positions. These results show that polyunsaturated fatty acids are distributed within the TAG molecule of human milk in a highly specific fashion, and that in the first month of lactation the maturation of the mammary gland does not affect the milk TAG structure.

International audience; Lost of adenomatous polyposis coli gene (Apc) disturbs the migration of intestinal epithelial cells but the mechanisms have not been fully characterized. Since we have demonstrated that SK3/KCa2.3 channel promotes cancer cell migration, we hypothesized that Apc mutation may affect SK3/KCa2.3 channel-mediated colon epithelial cell motility. We report evidence that SK3/KCa2.3 channel promotes colon epithelial cells motility. Following Apc mutation SK3/KCa2.3 expression is largely reduced leading to a suppression of the SK3/KCa2.3 channel mediated-cell migration. Our findings reveal a previously unknown function of the SK3/KCa2.3 channel in epithelial colonic cells, and suggest that Apc is a powerful regulator SK3/KCa2.3 channel.

Lifestyle and nutritional factors have been recognized to influence breast cancer survival, irrespective of genomic alterations that are the hallmarks of the disease. The biological and molecular mechanisms involved in the effects of dietary polyunsaturated fatty acids and breast cancer response to treatments in clinical and preclinical studies have been reviewed. Among nutrients, rumenic acid, a naturally occurring CLA isomer and n-3 docosahexaenoic acid (DHA) a highly unsaturated fatty acid, have emerged due to their potential to increase cancer treatment efficacy without additional side effects. In this review, we analyze the literature evidence that breast cancer treatment and outcome could be improved through an adjuvant dietary supplementation. Such an original approach would involve two successive phases of breast cancer treatment: an initial sensitization of residual tumor cells to chemotherapy and to radiation therapy with dietary DHA; then a prevention of metastatic re-growth with a prolonged rumenic acid supplementation. Safety is not anticipated to be a critical issue, although it has to be assessed in the long term. Dietary supplements, used in combination to anti-cancer agents, should be provided under medical prescription. Such an original use of fatty acids in breast cancer treatment could provide the lipid field with a new avenue to impact public health.

Objective This phase II investigated efficacy and tolerability of gefitinib in combination with paclitaxel (P) and carboplatin (C) for second-line treatment of patients (pts) with ovarian, tubal or peritoneal adenocarcinoma. Patients and methods Women (>18 years) with platinum-resistant/refractory (relapsed 6 months) disease after first-line platinum-based and P chemotherapy. Pts received 6–8 cycles of gefitinib (500 mg/day), P (175 mg/m 2 3 h infusion) and C (AUC 5) every 3 weeks, followed by gefitinib alone. The primary endpoint was objective response rate (ORR) (RECIST or Rustin criteria). Results Sixty-eight patients (26 resistant/refractory and 42 sensitive) were enrolled (median age: 57 years). ORR and disease control rates were 19.2% and 69.2% for resistant/refractory, and 61.9% and 81.0%, for sensitive disease. Median time to progression and overall median survivals were 6.1 and 16.9 months for resistant/refractory and 9.2 and 25.7 months for sensitive disease. Grade 3/4 toxicities (in ≥10% patients) were neutropenia (59%), diarrhea (25%), leukopenia (22%), anemia (13%), and acne (13%). Two secondary myelodysplastic syndromes (MDS) and one secondary acute leukemia occurred during treatment, and one MDS 34 months after treatment discontinuation. Conclusion Gefitinib, administered in combination with paclitaxel and carboplatin, provides a good clinical response but associated with an increased risk of hematologic disorders.

Voltage-gated sodium channels (Na(V)) are functionally expressed in highly metastatic cancer cells derived from nonexcitable epithelial tissues (breast, prostate, lung, and cervix). MDA-MB-231 breast cancer cells express functional sodium channel complexes, consisting of Na(V)1.5 and associated auxiliary beta-subunits, that are responsible for a sustained inward sodium current at the membrane potential. Although these channels do not regulate cellular multiplication or migration, their inhibition by the specific blocker tetrodotoxin impairs both the extracellular gelatinolytic activity (monitored with DQ-gelatin) and cell invasiveness leading to the attenuation of colony growth and cell spreading in three-dimensional Matrigel-composed matrices. MDA-MB-231 cells express functional cysteine cathepsins, which we found play a predominant role ( approximately 65%) in cancer invasiveness. Matrigel invasion is significantly decreased in the presence of specific inhibitors of cathepsins B and S (CA-074 and Z-FL-COCHO, respectively), and co-application of tetrodotoxin does not further reduce cell invasion. This suggests that cathepsins B and S are involved in invasiveness and that their proteolytic activity partly depends on Na(V) function. Inhibiting Na(V) has no consequence for cathepsins at the transcription, translation, and secretion levels. However, Na(V) activity leads to an intracellular alkalinization and a perimembrane acidification favorable for the extracellular activity of these acidic proteases. We propose that Na(v) enhance the invasiveness of cancer cells by favoring the pH-dependent activity of cysteine cathepsins. This general mechanism could lead to the identification of new targets allowing the therapeutic prevention of metastases.

Background: This multicentre, international phase II trial evaluated the efficacy and safety profile of a first-line combination of oral vinorelbine plus capecitabine for women with metastatic breast cancer (MBC). Methods: Patients with measurable, HER2-negative disease received, as a first line in metastatic setting, 3-weekly cycles of oral vinorelbine 80 mg m−2 (after a first cycle at 60) on day 1 and day 8, plus capecitabine 1000 mg m−2 (750 if ⩾65 years of age) twice daily, on days 1–14. Treatment was continued until progression or unacceptable toxicity. Results: A total of 55 patients were enrolled and 54 were treated (median age: 58.5 years). Most (78%) had visceral involvement and 63% had received earlier (neo)adjuvant chemotherapy. The objective response rate (RECIST) in 49 evaluable patients was 51% (95% confidence interval (CI), 36–66), including complete response in 4%. The clinical benefit rate (response or stable disease for ⩾6 months) was 63% (95% CI, 48–77). The median duration of response was 7.2 months (95% CI, 6.4–10.2). After a median follow-up of 41 months, median progression-free survival was 8.4 months (95% CI, 5.8–9.7) and median overall survival was 29.2 months (95% CI, 18.2–40.1). Treatment-related adverse events were manageable, the main grade 3–4 toxicity was neutropaenia (49%); two patients experienced febrile neutropaenia and three patients had a neutropaenic infection (including one septic death). A particularly low rate of alopaecia was observed. Conclusion: These results show that the all-oral combination of oral vinorelbine and capecitabine is an effective and well-tolerated first-line regimen for MBC.

The potential for dietary fat to prevent breast cancer makes identification of defined molecules a mandatory step. In order to circumvent the limitations and/or bias of dietary exposure assessment tools, we have used the fatty acid composition of white adipose tissue as biomarker of past lipid intake. When considered separately, candidate fatty acids identified as favourable on the basis of their association with breast cancer risk have usually led to inconsistent results in dietary intervention studies carried out in rats. This inconsistency indicates that any approach based on a single fatty acid should be abandoned for an integrated view over the complex lipid interactions, which finally determines the lipidome, the lipid profile that is found in individuals. We reappraised the role of the complete lipid profile through a comprehensive study of adipose tissue fatty acids obtained in patients with benign or malignant breast tumors. Rather than a single fatty acid, a composite indicator combining elevated monounsaturates and low n-6/n-3 fatty acid ratio was associated with decreased breast cancer risk. The lipidome may provide the opportunity to quantify the modifiable part of the risk of breast cancer. The lipidome may be used as a template for designing proper dietary modifications in order to delay the occurrence of breast cancer. Which dietary modifications should be undertaken in order to bring a pertinent change to the lipidome with respect to the risk of breast cancer is currently unknown. The lipidome may allow the individualization of a high risk population of women, who may be targeted for a dietary prevention of breast cancer. The setting and validation of a high-throughput lipidomic station with analytical capabilities fitted to the need of mass screening is required. These two locks must be resolved before a primary prevention of breast cancer by diet could be contemplated.

International audience; Docosahexaenoic acid (DHA, a lipid of marine origin) has been found to enhance the activity of several anticancer drugs through an oxidative mechanism. To examine the relation between chemosensitization by DHA and tumor cells antioxidant status, we used two breast cancer cell lines: MDA-MB-231, in which DHA increases sensitivity to doxorubicin, and MCF-7, which does not respond to DHA. Under these conditions, reactive oxygen species (ROS) level increased on anthracycline treatment only in MDA-MB-231. This was concomitant with a decreased cytosolic glutathione peroxidase (GPx1) activity, a crucial enzyme for protection against hydrogen and lipid peroxides, while major antioxidant enzyme activities increased in both cell lines in response to ROS. GPx-decreased activity was accompanied by an accumulation of glutathione, the GPx cosubstrate, and resulted from a decreased amount of GPx protein. In rat mammary tumors, when a DHA dietary supplementation led to an increased tumor sensitivity to anthracyclines, GPx1 activity was similarly decreased. Furthermore, vitamin E abolished both DHA effects on chemotherapy efficacy enhancement and on GPx1 inhibition. Thus, loss of GPx response to an oxidative stress in transformed cells may account for the ability of peroxidizable targets such as DHA to enhance tumor sensitivity to ROS-generating anticancer drugs.

Contrast agents for ultrasound imaging, composed of tiny gas microbubbles, have become a reality in clinical routine. They are extensively used in radiology for detection and characterization of various tumors and in cardiology for left ventricular opacification. Recent experimental studies showed that ultrasound waves in combination with contrast agent microbubbles increase transiently cell membrane permeability in a process known as sonoporation. This effect is thought to allow foreign molecules to enter the cell. In that context, we explored the cell membrane's responses to microbubbles' oscillations as the mechanism is not completely understood. Breast cancer cell line in combination with contrast microbubbles were used. Ultrasound was applied using a transducer of 1 MHz center frequency transmitting a 10-cycle burst of different acoustic pressures repeated every 100 mus. Patch-clamp technique in whole cell configuration was used to explore transmembrane ion exchange through the variations in membrane potential. To characterize the activated ion channels, the variations of the intracellular calcium (Ca(2+)) concentration were explored using a fluorescent marker. The results revealed that ultrasound stimulation induces a rapid hyperpolarization of cell membrane potential when the microbubble is in direct contact with the cell, but the potential returned to its initial value when ultrasound stimulation stopped. The change in cell membrane potential indicates the activation of specific ion channels and depends on the quality of microbubble adhesion to the cell membrane. Microbubbles were shown to induce a mechanical stretch activating BKca channels. Simultaneous Ca(2+) measurements indicate a slow and progressive Ca(2+) increase that is likely a consequence of BKca channels opening not a cause. These results demonstrate that microbubbles' oscillations under ultrasound activation entail modulation of cellular function and signaling by t- riggering the modulation of ionic transports through the cell membrane. Cells response to the mechanical stretch caused by gentle microbubble oscillations is characterized by the opening of BKca stretch channels and a Ca(2+) flux, which might potentially trigger other cellular responses responsible for membrane sonopermeabilization.

In endometrial carcinoma, vaginal vault brachytherapy is performed to improve the local control rate and to decrease vaginal recurrences. To assess the best chronology of this brachytherapy compared to surgery, we have retrospectively analyzed results of treatment of patients treated either with preoperative brachytherapy (60 Gy) and then radical hysterectomy with bilateral salpingo oophorectomy (RH-BSO) (Group 1), or with RH-BSO and then postoperative brachytherapy (60 Gy) (Group 2). There were one hundred twenty-one patients in Group 1 and 63 in Group 2. The mean age was 61.8 years in Group 1 and 64.3 in Group 2. In Group 1, 73% of the patients were Stage I, and 77.6% were in Group 2. The two groups were comparable for histological grading and depth of tumoral invasion into the myometrium. Brachytherapy was delivered with one uterine and two vaginal sources in Group 1 and with three vaginal sources in Group 2. Doses to the reference volume and to reference points were calculated according to ICRU recommendations. Brachytherapy data were similar in the two groups except reference volume, which was smaller in Group 2. Local control rate was 87% in Group 1 and 91% in Group 2. Distant metastasis occurred in 12% of patients in Group 1 and 9% in Group 2. The 5-year actuarial survival rate was 84% in Group 1 and 89% in Group 2. Regarding stage, histological grading, and depth of tumoral invasion, no differences were observed between the two therapeutic groups. The only prognostic factor in the entire population was Stage. The 5-year actuarial survival rate was 91% for Stage I patients and 69% for Stage II (p value less than 0.03). The late severe complication rate was 14% in Group 1 and 7.9% in Group 2, a difference which was not statistically significant. We concluded that since no differences were observed between the two techniques, vaginal brachytherapy should be performed postoperatively when surgery is the first treatment (Stage I or II, grade 1 or 2, and no deep tumoral invasion into the myometrium).

Contrast ultrasound imaging is a noninvasive imaging modality using gas microbubbles. However disorders of the heart rate expressed by the appearance of premature ventricular contractions (PVCs) occur in few patients. We have recently shown through electrophysiological studies that ultrasound activated microbubbles oscillate and induce a mechanical stress on the cell membrane resulting in the activation of stretch activated channels (SAC). These channels, described initially in the muscular cells, are ionic channels expressed in all cell types. In the heart, their activation can trigger arrhythmias. The aim of this study is to demonstrate, in vivo and in vitro, the relationship between PVC and SAC opening by ultrasound contrast agents (UCA) during ultrasound (US) exposure. Three sets of experiments were conducted: two on animal models with microbubbles and mechanical stress and one in vitro. 5 anesthetized rats were used. PVC's were created in vivo using SonoVuetrade microbubbles at a rate of 0.5 ml/min. The microbubbles were injected intravenously through the tail vein. US consisted of 40-cycle waveforms at 1 MHz and peak negative pressures up to 300 kPa. A PVC animal model based on a manually-induced mechanical stretch was used. The model consisted of stimulations by a flexible catheter introduced into the rat aorta and pushed until the left ventricle. PVC's were quantified through ECG measurements. In-vitro, patch Clamp technique in ruptured-patch whole cell configuration was used to monitor the changes in the electrical potential on HL-1 heart cell line during manual stimulation. In vivo, UCA and US at 300 kPa induced modification of rat's ECG while pressure below 300 kPa did not induce any PVC. US alone did not induce PVC at any acoustic pressures. Similar PVC's were also observed in the animal model but ceased immediately after the stimulation. In vitro, electrophysiological recordings showed that the mechanical stretch engendered a cell membrane depolarization due to SAC opening. The cell membrane potential depolarized as a consequence of the manual stimulation and returned to its initial value when the stimulation was released. This effect might trigger additional action potential and by that the generation of extra contractions such as PVC's. We presume that PVC's are triggered through the opening of stretch activated ion channels. This study indicates that PVCs induced by UCA are related to mechanical interaction between cell membrane and oscillating microbubbles.

The effects of ann-3 PUFA-enriched diet on cardiac cell membrane phospholipid fraction compositions and associated protein kinase-C (PKC) translocation modification have never been studied in higher mammals. This is of importance since membrane fatty acid composition has been shown to influence PKC signalling pathways. In the present study, we have tested whether the incorporation ofn-3 PUFA in cardiac membrane phospholipids correlated with changes in the fatty acid composition of diacylglycerols (DAG) and led to a differential translocation of PKC isoforms. Two groups of five dogs were fed the standard diet supplemented with palm oil or fish oil for 8 weeks. Dogs fed a fish oil-enriched diet showed a preferential incorporation of EPA and, to a lesser extent, of DHA, at the expense of arachidonic acid, in the circulating TAG, plasma phospholipids, erythrocyte phospholipids and cardiomyocyte phospholipid fractions. Analysis of 1,2-DAG fatty acid composition also indicated a preferential enrichment of EPA compared with DHA. Associated with these results, a reduction in the expression of PKC-δ and PKC-ε isoforms in the particulate fractions was observed whereas no effect was seen for PKC-α and PKC-ζ. We conclude that a fish oil-enriched diet induces a modification in fatty acid composition of cardiac membrane phospholipids, associated with a differential translocation of PKC isoforms. These results can be explained by the production of structurally different DAG that may participate in some of the protective effects ofn-3 PUFA against various chronic diseases.

Any factor affecting BRCA gene regulation may be of interest in the prevention of breast tumourigenesis. We studied the influence of dietary docosahexaenoic acid (DHA), a major omega-3 fatty acid present in marine products, on rat autochthonous mammary tumourigenesis. DHA-supplementation significantly reduced the incidence of tumours (30%, P=0.007) and led to a 60% increase (P=0.02) in BRCA1 protein level. Since DHA influences the product of a major tumour suppressor gene, this finding may contribute to the observation that high-fish consumption reduces the risk of breast cancer.

Ionic channel activity is involved in fundamental cellular behaviour and participates in cancerous features such as proliferation, migration and invasion which in turn contribute to the metastatic process. In this study, we investigated the expression and role of voltage-gated sodium channels in non-small-cell lung cancer cell lines. Functional voltage-gated sodium channels expression was investigated in normal and non-small-cell lung cancer cell lines. The measurement, in patch-clamp conditions, of tetrodotoxin-inhibitable sodium currents indicated that the strongly metastatic cancerous cell lines H23, H460 and Calu-1 possess functional sodium channels while normal and weakly metastatic cell lines do not. While all the cell lines expressed mRNA for numerous sodium channel isoforms, only H23, H460 and Calu-1 cells had a 250 kDa protein corresponding to the functional channel. The other cell lines also had another protein of 230 kDa which is not addressed to the membrane and might act as a dominant negative isoform to prevent channel activation. At the membrane potential of these cells, channels are partially open. This leads to a continuous entry of sodium, disrupting sodium homeostasis and down-stream signaling pathways. Inhibition of the channels by tetrodotoxin was responsible for a 40-50% reduction of in vitro invasion. These experiments suggest that the functional expression of voltage-gated sodium channels might be an integral component of the metastatic process in non-small-cell lung cancer cells probably through its involvement in the regulation of intracellular sodium homeostasis. These channels could serve both as novel markers of the metastatic phenotype and as potential new therapeutic targets.

Summary Background and aim Dietary polyethylene glycol (PEG) is extraordinarily potent in the chemoprevention of experimental colon carcinogenesis. PEG is used to treat constipation in France and in the USA. French laxatives include Forlax® (PEG4000), Movicol® and Transipeg® (PEG3350), and Idrocol® (pluronic F68). This study tests the hypothesis that use of a PEG-based laxative might reduce the prevalence of colorectal tumors. Methods In this population-based study, consecutive patients attending for routine total colonoscopy were enrolled during four months by the gastroenterologists of Indre-et-Loire. They were asked if they had previously taken a laxative or a NSAID. Age, gender, previous polyps, family history of colorectal cancer, constipation, digestive symptoms were also recorded. Tumors found during colonoscopy were categorized histologically. Results Records from 1165 patients fulfilled the inclusion criteria, 607 women and 498 men, mean age 58.3. Among those, 813 had no tumor, 329 had adenomas, and 23 had carcinomas. In a univariate analysis, older age, male gender, lack of digestive symptom, and previous polyps were more common in patients with colorectal tumors. In contrast, previous Forlax® intake was more common in tumor-free patients (odds ratio (OR) any use/no use, 0.52; 95% confidence interval, 0.27–0.94). More people used Forlax®, which contains a higher dose of PEG than the other PEG-laxatives, whose ORs were smaller than one, but did not reach significance. In multivariate analysis, older age and male gender were associated with higher risk, and NSAIDs use with lower risk, of colorectal tumors. Conclusion Forlax® users had a halved risk of colorectal tumors in univariate analysis, which suggests that PEG may prevent carcinogenesis.

Purpose: To investigate whether dietary docosahexaenoic acid (DHA), a peroxidizable polyunsaturated ω-3 fatty acids, sensitizes rat mammary tumors to anthracyclines and whether its action interferes with tumor vascularization, a critical determinant of tumor growth. Experimental Design: Female Sprague-Dawley rats were initiated by N-methylnitrosourea to develop mammary tumors and then assigned to a control group (n = 18), receiving a supplementation of palm oil, or to a DHA group (n = 54), supplemented with a microalgae-produced oil (DHASCO, 1.5 g/d). The DHA group was equally subdivided into three subgroups with addition of different amounts of α-tocopherol. Epirubicin was injected weekly during 6 weeks after the largest tumor reached 1.5 cm2, and subsequent changes in the tumor surface were evaluated. Tumor vascularization was assessed by power Doppler sonography before and during chemotherapy. Results: DHA and α-tocopherol were readily absorbed and incorporated into rat tissues. Epirubicin induced a 45% mammary tumor regression in the DHA-supplemented group, whereas no tumor regression was observed in the control group. In the DHA group, before chemotherapy was initiated, tumor vascular density was 43% lower than in the control group and remained lower during chemotherapy. Enhancement of epirubicin efficacy by DHA was abolished in a dose-dependent manner by α-tocopherol, and the same trend was observed for DHA-induced reduction in tumor vascular density. Conclusions: Dietary DHA supplementation led to a reduction in tumor vascularization before the enhancement of any response to anthracyclines, suggesting that DHA chemosensitizes mammary tumors through an inhibition of the host vascular response to the tumor.

To investigate whether dietary alpha-linolenic acid (ALA) content alters the effect of beta-carotene on mammary carcinogenesis, we conducted a chemically induced mammary tumorigenesis experiment in rats randomly assigned to four nutritional groups (15 rats per group) varying in beta-carotene supplementation and ALA content. Two oil formula-enriched diets (15 %) were used: one with 6 g ALA/kg diet in an essential fatty acids (EFA) ratio of linoleic acid:ALA of 5:1 w/w (EFA 5 diet), the other with 24 g ALA/kg diet in an EFA ratio of 1:1 w/w (EFA 1 diet), both designed with a similar linoleic acid content. beta-Carotene was either added (10 mg/kg diet per d) or not added to these diets. beta-Carotene supplementation led to decreased tumour incidence and tumour growth when added to the EFA 5 diet, whereas it had no effect when added to the EFA 1 diet. The decreased tumour growth did not result from an involvement of lipoperoxidation (tumour malondialdehyde content being similar between the groups) or from an inhibition of tumour cell proliferation (as there was an unchanged S phase fraction in the tumours). We concluded that an adequate content of ALA in the diet is required to allow a protective effect of beta-carotene in mammary carcinogenesis. Whether such an interaction between ALA and beta-carotene influences the risk of breast cancer in women needs to be investigated.

The potential for dietary fat to interfere with the development of breast cancer by delaying its occurrence makes the identification of defined molecules a mandatory step in cancer prevention. In order to circumvent the limitations and/or bias of dietary exposure assessment tools, biomarkers of past lipid intake such as the fatty acid composition of white adipose tissue have been used. When considered separately, candidate fatty acids identified as favorable on the basis of their association with breast cancer risk have usually led to inconsistent results in animal intervention studies. This inconsistency indicates that any approach based on a single fatty acid should be abandoned for an integrated view over the complex lipid interactions which finally determines the lipidome, the lipid profile that is found in individuals. This article presents a reappraisal of the role of the lipid profile through a comprehensive reanalysis of adipose tissue fatty acid composition obtained in patients with benign or malignant breast tumors as well as in experimental animals during dietary interventions. Rather than a single fatty acid, a composite indicator combining elevated monounsaturates and low ω6/ω3 fatty acid ratio was associated with breast cancer protection. This lipidome may become the template for identifying breast cancer risk related to diet, and for designing proper dietary modifications to delay the occurrence of breast cancer, although the universality of the findings cannot be assessed from a single study. (Cancer Epidemiol Biomarkers Prev 2006;15(3):416–21)

Long-chain omega-3 polyunsaturated fatty acids are thought to inhibit the development of breast cancer. We investigated the effects of docosahexaenoic and eicosapentaenoic acids on the proliferation of MDA-MB-231 human mammary epithelial cells. Both docosahexaenoic and eicosapentaenoic acids decreased cell growth with a higher efficiency for docosahexaenoic acid (87% at 100 microM versus 74% for eicosapentaenoic acid). The effect on specific cell cycle phases was studied. G2/M duration was markedly increased by docosahexaenoic and by eicosapentaenoic acids (respectively by more than seven- and six-fold at 50 microM) when cells were synchronized at the G1/S boundary and released in the cell cycle. In contrast, there was no alteration of G1 or S phases. The expression of cyclin A, cyclin B1 and cyclin-dependent kinase 1, the regulators required for the progression from G2 to mitosis, were all decreased by these fatty acids (western blot). Since omega-3 fatty acids had no effect on the S phase, thus ruling out an involvement of cyclin A in their anti-proliferative effect, we examined whether the regulation of the cyclin-dependent kinase 1-cyclin B1 complex was altered. Upon omega-3 fatty acids treatment, cyclin B1 phosphorylation was inhibited and the expression of the cell division cycle 25C phosphatase, which dephosphorylates cyclin-dependent kinase 1, was decreased. We conclude that the anti-proliferative effect of omega-3 fatty acids occurs via the regulation of the cyclin-dependent kinase 1-cyclin B1 complex.

Potassium channels have been involved in epithelial tumorigenesis but the role of small-conductance Ca2+-activated K+ channels is unknown. We report here that small-conductance Ca2+-activated K+ channels are expressed in a highly metastasizing mammary cancer cell line, MDA-MB-435s. Patch-clamp recordings showed typical small-conductance Ca2+-activated K+ channel–mediated currents sensitive to apamin, 4-aminopyridine, and tetraethylammonium. Moreover, the cells displayed a high intracellular calcium concentration, which was decreased after 24 hours of apamin treatment. By regulating membrane potential and intracellular calcium concentration, these channels were involved in MDA-MB-435s cell migration, but not in proliferation. Only SK3 protein expression was observed in these cells in contrast to SK2, which was expressed both in cancer and noncancer cell lines. Whereas small interfering RNA directed against SK3 almost totally abolished MDA-MB-435s cell migration, transient expression of SK3 increased migration of the SK3-deficient cell lines, MCF-7 and 184A1. SK3 channel was solely expressed in tumor breast biopsies and not in nontumor breast tissues. Thus, SK3 protein channel seems to be a new mediator of breast cancer cell migration and represents a potential target for a new class of anticancer agents. [Mol Cancer Ther 2006;5(11):2946–53]

Experiments in animal models of mammary carcinogenesis suggest that fatty acids promote mammary tumors development. This effect depends first on the amount then on the type of fatty acids available. n-6 fatty acids such as linoleic acid generally stimulates mammary tumor growth, while n-3 fatty acids oppose this effect. Conjugated diene fatty acids (CLA) inhibit mammary carcinogenesis when brought at elevated amount. There are limitations in using an animal model in the analysis between nutrition and colorectal cancers. This is ascribable to the following: firstly, the digestive tract of rodents if different from that of humans and secondly, the induction of colon cancer in these animals (chemical carcinogenesis, injection of cancerous cells or transgenesis) does not mimic human colon carcinogenesis. However, on the basis of numerous published data, some important correlations have arisen that could generate hypotheses and guide new epidemiological/interventional and experimental studies. In these animal models it appears that an adequate supply of n-3 PUFAs and oleic acid in food may exert a protective effect at all stages of colon carcinogenesis. On the other hand, an excessive consumption of n-6 PUFAs and of saturated fatty acids could promote colon cancers.

The relationship between high fish consumption and low mortality following coronary heart disease (CHD) and low incidence of breast cancer was first mentioned 3 decades ago. The fishes of interest are rich in omega-3 long-chain polyunsaturated fatty acids (omega-3 LC-PUFAs), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which could be the active nutrients. The current consensus about cardioprotection is that omega-3 LC-PUFAs would mainly exert antiarrhythmic effects. One of the proposed mechanisms is that circulating non-esterified LC-PUFAs partition into cardiac cells membrane phospholipids and exert a direct effect on ionic channels and/or modify intracellular calcium homeostasis. In another hypothesis, changes in the metabolism of phosphoinositides would be involved and lead to the differential activation of PKC isoforms. As compared to the mechanisms proposed for the cardioprotective effects of omega-3 LC-PUFAs, less is known about the molecular mechanisms involved in breast cancers prevention. Some proposed mechanisms such as the modulation of phosphoinositides metabolism and/or modulation of intracellular calcium homeostasis, are common to both pathologies. Other hypotheses involve the alteration of the cellular redox status induced by highly peroxidizable polyunsaturated fatty acids (FA), or the modulation of gene expression, both phenomena being tightly linked to apoptosis. In this review, we report and compare some proposed mechanisms for the involvement of omega-3 LC-PUFAs in both cardiac and breast cancer protection. Deliberately, we chose to discuss only the mechanisms, which are less described in other reviews such as ionic channels in cancer, calcium homeostasis, PKC activation or matrix metalloproteinases in both cancer and cardiac models. The leitmotiv along this review is that cardio- and cancero-protective effects use common pathways. Comparison of the cellular effects might therefore help to highlight the "protective" pathways.

International audience; Polyunsaturated fatty acids (PUFAs) have been reported to enhance the efficacy of chemotherapeutic agents that produce reactive oxygen species such as anthracyclines. We previously reported in a human breast cancer cell line that the increased cytotoxic activity of anthracyclines by several PUFAs was abolished by antioxidants and enhanced by pro-oxidants, suggesting that lipid peroxidation was involved in this effect. To determine the relevance of this observation in vivo, we examined the effect of the oxidative status of the diet on the activity of epirubicin against N-methylnitrosourea-induced mammary tumors in Sprague-Dawley rats. Three groups of rats were fed a basal diet enriched with dietary n-3 PUFA (sardine oil, 15%) alone (control group), with addition of an antioxidant (alpha-tocopherol, 100 UI/kg diet), or with addition of an oxidant system (dehydroascorbate/naphthoquinone). When the first mammary tumor reached 1 cm2, epirubicin was administrated weekly for 3 wk, and subsequent change in tumor size was documented over time. Two weeks after the end of epirubicin injections, tumor size was increased by 34% in the control group. In the pro-oxidant group, tumor size was decreased by 50%. In contrast, tumor size was increased by 188% in the antioxidant group. Thus, addition of pro-oxidants in a fish oil-enriched diet increased the sensitization of mammary tumors to chemotherapy, whereas addition of alpha-tocopherol suppressed tumor response in vivo, indicating that interaction between components of the diet has to be carefully controlled during chemotherapy.

Dietary docosahexaenoic acid (DHA), which integrates into tumor cell membranes, has been reported to enhance the efficacy against tumors of cytotoxic drugs that induce reactive oxygen species (ROS). Because ionizing radiation also generate ROS, we initiated a study to determine whether dietary DHA might sensitize mammary tumors to irradiation. Mammary tumors were induced by N-methylnitrosourea (NMU) in Sprague-Dawley rats. The optimal dose of radiation to examine the effect of DHA on tumor response to irradiation was determined to be 18 grays (Gy) using a 4-6 MeV electron beam (according to the depth of the target volume) delivered in a single fraction from a linear accelerator. Two groups of rats were fed a basal diet containing 7% of a mixture of peanut and rapeseed oils enriched with 8% of an oil containing either a low (palm oil) or high (DHASCO oil containing 40% DHA) DHA content. DHA group was equally subdivided into 2 groups without or with addition of vitamin E (100 IU/kg diet). Irradiation was carried out when the first tumor in each rat reached 1.5 cm2 and subsequent change in tumor size was documented over time. DHA level in adipose tissue, taken as a biomarker, was higher in the DHA supplemented group compared to the control group. Vitamin E level in liver, the best storage for this compound, was higher in the vitamin E supplemented DHA group compared to the DHA group. Tumor size decreased by 60% at 12 days after irradiation in the DHA group vs. 31% in the control group (p = 0.03) and 36% in the DHA plus vitamin E group. Therefore, dietary DHA sensitized mammary tumors to radiation. The addition of vitamin E inhibited the beneficial effect of DHA, suggesting that this effect might be mediated by oxidative damage to the peroxidizable lipids.

Changes in tumor vascularization may be involved in tumor regression after anticancer treatments. We therefore studied the relationship between tumor vascularization and tumor response according to treatment by irradiation (RT), epirubicin (EPI), or antiangiogenic agent TNP-470 in a nitrosomethyl-ureas-induced rat mammary tumor model by measuring the changes in tumor blood flow using high-frequency Power-Doppler sonography.Mammary tumors were induced in female Sprague-Dawley rats by a single s.c. injection of nitrosomethyl-ureas. After tumor areas reached 2 cm(2), the animals received four weekly injections of epirubicin (EPI group), or a single fraction of 18 Gy (RT group), or six injections of TNP-470 within 12 days (TNP group), or both (RT combined with TNP-470, RT+TNP group). Power-Doppler sonography quantification of tumor vascularization (PDI) was performed before and 12 days after initiation of treatment. Tumor shrinkage was later evaluated and compared with the early changes in PDI values.Compared with the control group, EPI induced an arrest in tumor growth. A similar effect was obtained with TNP-470. There was a decrease in tumor area after RT, but administration of TNP-470 combined with RT did not further enhance this effect. Changes in tumor area paralleled changes in PDI in the EPI group. Furthermore, changes in PDI 7 days after RT were associated with further tumor change in the RT groups, whereas they were independent of the antitumor effect of TNP-470.Changes in functional tumor vascularization evolution appeared to be closely associated with tumor regression after anticancer treatment.

Objective. To investigate the changes occurring in the vascularization of tumors during irradiation, we used a model of autochthonous mammary tumors in rats and assessed early vascular changes after irradiation by power Doppler sonography. Methods. Mammary tumors were induced in 24 female Sprague Dawley rats by a single subcutaneous injection of N-nitroso N-methyl urea. After tumor areas reached 1 cm 2 , the animals received a single fraction of 18-Gy radiation or intraperitoneal saline injection. Power Doppler sonographic quantification of detected vessels was performed 1 day before irradiation and 7 days after the use of a power Doppler index of 5 different tumor imaging planes. Final tumor shrinkage was compared with early changes in the power Doppler index. Not all tumors regressed in a similar fashion. Radiosensitive tumors were defined as tumors with a greater than 50% decrease in baseline area 28 days after irradiation, whereas radioresistant tumors were tumors with a less than 50% decrease in baseline area. Statistical analysis was performed by the Mann-Whitney U test. Results. Tumor area changes were similar in radioresistant and radiosensitive tumors 7 days after irradiation (-41 % and -35%, respectively; P >.05, not significant), whereas reduction in the power Doppler index was significantly greater in radiosensitive tumors (mean value, -63%) than in radioresistant tumors (mean value, -12%) (P =.001). Late tumor regrowth was correlated with day 7 power Doppler index changes (P =.009). A 40% reduction in the power Doppler index at day 7 distinguished 8 of 9 radiosensitive tumors and 8 of 9 radioresistant tumors (P =.003). Conclusions. This study suggests that early changes in tumor perfusion as assessed by power Doppler sonography after tumor irradiation may precede the long-term tumor regression.

To determine whether the purified 9c,11t conjugated linoleic acid (CLA) isomer, the main dietary isomer, is biologically active on mammary tumor growth, we carried out a dietary intervention study designed to compare its effects with those of a mixture of CLA isomers on the incidence and growth of autochthonous mammary tumors induced by methylnitrosourea in rats. After the initiation step, rats were fed a sunflower oil-based diet (5%) and separated into three experimental groups supplemented with either a 1% homemade synthesized 9c,11t isomer, a 1% CLA isomer mixture, or free fatty acids prepared from sunflower oil for the control group. We found that, in the two CLA groups compared with the control group, CLA levels were about 30 times higher in mammary fat pads and about 10 times higher in tumor tissues. Compared with the control group, there was a 44% and 45% decrease in tumor mass per rat in the CLA mixture and the 9c,11t groups, respectively, at 20 wk of diet (P0.05). There was a nonsignificant trend for a decrease multiplicity in CLA groups compared with the control group, with a 30% and 35% decrease in the CLA mixture and the 9c,11t groups, respectively. Incidence and latency were not significantly different between the dietary groups. Although the effect was specifically restricted in reduction in tumor mass, we concluded that the main CLA isomer found in human diet has anticarcinogenic properties in experimental mammary carcinogenesis.

The association between the level of conjugated linoleic acid (CLA) in breast adipose tissue at the time of diagnosis and the subsequent development of metastasis was examined in a cohort of 209 patients presenting with an initially localized breast cancer. CLA level in breast adipose tissue was used as a qualitative biomarker of its past dietary intake. Biopsies of adipose tissue were obtained at the time of initial surgery. A CLA-enriched fraction was prepared by high performance liquid chromatography and CLA measured as a percentage of total fatty acids, using capillary gas chromatography. Mean CLA level was low (0.44% of total fatty acids) and the range between patients was narrow (0.19-0.85). With a median follow-up time of 7.5 yr, 45 patients developed metastases. A Cox proportional hazard regression model was used to identify prognostic factors. We did not find any significant association between CLA level in adipose fat and either the prognostic factor (tumor size, nodal status, histoprognostic grade, mitotic index, and estrogen or progesterone receptors) or the risk of metastasis or death. We concluded that CLA are unlikely to be involved in survivorship. However, the hypothesis that a higher intake of CLA might have a protective effect on the risk of metastasis cannot be ruled out from these data, since the level of CLA in breast cancer patients' adipose tissue is likely to be too low and the range of CLA distribution too narrow for any protection to be detectable.