Charles Couet

Improving outcome of chemotherapy of metastatic breast cancer by docosahexaenoic acid: a phase II trial

Background:Breast cancer becomes lethal when visceral metastases develop. At this stage, anti-cancer treatments aim at relieving symptoms and delaying death without resulting in additional toxicity. On the basis of their differential anti-oxidant defence level, tumour cells can be made more sensitive to chemotherapy than non-tumour cells when membrane lipids are enriched with docosahexaenoic acid (DHA), a peroxidisable and oxidative-stress-inducing lipid of marine origin.Methods:This open-label single-arm phase II study evaluated the safety and efficacy (response rate), as primary end points, of the addition of 1.8 g DHA daily to an anthracycline-based chemotherapy (FEC) regimen in breast cancer patients (n=25) with rapidly progressing visceral metastases. The secondary end points were time to progression (TTP) and overall survival (OS).Results:The objective response rate was 44%. With a mean follow-up time of 31 months (range 2–96 months), the median TTP was 6 months. Median OS was 22 months and reached 34 months in the sub-population of patients (n=12) with the highest plasma DHA incorporation. The most common grade 3 or 4 toxicity was neutropaenia (80%).Conclusion:DHA during chemotherapy was devoid of adverse side effects and can improve the outcome of chemotherapy when highly incorporated. DHA has a potential to specifically chemosensitise tumours.

Triacylglycerol structure of human colostrum and mature milk

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 thesn-1 position, palmitic acid for thesn-2 position and linoleic acid for thesn-3 position. Linoleic and α-linolenic acids exhibited the same pattern of distribution and they were both found primarily in thesn-3 (50%) andsn-1 (30%) positions. Their longer chain analogs, arachidonic and docosahexaenoic acids, were located in thesn-2 andsn-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.

Fatty acids and breast cancer: sensitization to treatments and prevention of metastatic re-growth.

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.

Diet, Cancer, and the Lipidome

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)

Prognostic significance of tumor phosphatidylcholine stearic acid level in breast carcinoma

The involvement of lipid enzymes in the action of oncogenes at the cell membrane level has suggested that membrane lipids could play a role in modulating the growth of tumors. We previously found that breast cancer patients with a low level of polyunsaturated fatty acids in their primary tumors phosphatidylethanolamine had a high risk of early occurrence of visceral metastasis. In the present study, we prospectively examined whether fatty acid composition of tumor membrane phosphatidylcholine had a prognostic significance in a series of 63 patients with a localized presentation of breast cancer. Membrane phospholipids were extracted from the carcinoma tissue obtained at the time of surgery, phosphatidylcholine was purified, and its fatty acids were analyzed by capillary gas chromatography. During the follow-up period, 20 patients developed metastasis. In these patients, the proportion of stearic acid containing phosphatidylcholine was significantly lower than it was in the tumors of the 43 patients who remained metastasis-free. Multivariate analysis according to Cox showed that low stearic acid level in tumor phosphatidylcholine and high mitotic index were independently predictive of subsequent metastasis. The predictive value of stearic acid level on metastasis risk was higher in node-positive patients than in node-negative patients, allowing individualization of a subgroup of low stearic acid level, node-positive patients with very poor prognosis. We concluded that stearic acid level in tumor membrane phosphatidylcholine is an independent intra-tumor marker of breast cancer prognosis. This finding is new evidence that tumors structural lipids are linked to the growth of breast cancer.

Anthropometric values in an elderly French population

We compared anthropometric indices in samples of elderly people aged 65 years and over living in two French areas. The samples were divided into four age-groups (65-69, 70-74, 75-79 and over 80 years). We observed interregional differences in women aged 65-69 years and in men aged 65-74 years. Weight and anthropometric variables related to body fat percentage and to muscle mass showed a decline with age as already reported by others. We established anthropometric percentile values according to sex in pooled subjects when no integrated difference was found. The 50th percentile of arm circumference, muscle arm circumference and triceps skinfold was higher, and the 50th percentile of body mass index was lower than the one reported for the same indices from an elderly Welsh population. Our results show that an interregional difference in anthropometric indices exists in the elderly. The differences which are observed between our results and those reported from a British population emphasize the importance of establishing local values for the elderly population.

Parent-offspring correlations in pedometer-assessed physical activity.

Background Physical activity is a major component of a healthy lifestyle in youth and adults. To identify determinants of this complex behavior is an important research objective in the process of designing interventions to promote physical activity at population level. In addition to individual determinants, there is evidence documenting familial influences on physical activity. However, the few studies that have addressed this issue with objective measures did not provide data on parent-offspring physical activity relationships throughout childhood and adolescence. The purpose of this study was to assess familial correlations in pedometer-assessed physical activity. Methods We measured ambulatory activity in 286 French nuclear families (283 mothers, 237 fathers, and 631 children aged 8–18 years) by pedometer recordings (Yamax Digiwalker DW 450) over a week. Correlations were computed with their 95% confidence intervals (CI) for spouse pairs, siblings, mother-offspring, and father-offspring. Data were expressed as steps per day and computed both for the full recording period and separately for weekdays and weekends. Results The correlations were the highest between siblings (r = 0.28, 95%CI: 0.17–0.38). Parent–offspring correlations were significant in mothers (r = 0.21, 95%CI: 0.12–0.30), especially between mothers and daughters (r = 0.24, 95%CI: 0.12–0.36 vs. r = 0.18, 95%CI: 0.05–0.31 for sons), but were almost nonexistent in fathers. Correlations were generally higher on weekend days compared to weekdays. Mother-offspring correlations did not decrease with increasing age of children (r = 0.17, 95%CI: 0.00–0.34 in 8–11-year-olds, r = 0.20, 95%CI: 0.07–0.33 in 12–15-year-olds, and r = 0.25, 95%CI: 0.07–0.39 in ≥16-year-olds). Finally, between-spouse correlations were significant only during weekend days (r = 0.14, 95%CI: 0.01–0.27). Conclusion Ambulatory activity correlated within families, with a possible mother effect. Mother-offspring correlations remained significant through the transition from childhood to adolescence. Further studies are required to better understand the respective influences of shared activities, parental modeling and support as well as genetic factors on the familial aggregation of physical activity.

Mechanisms and kinetics of alpha-linolenic acid uptake in Caco-2 clone TC7

The uptake kinetics of alpha-linolenic acid (18:3(n - 3)), an essential fatty acid, were investigated in the human intestinal cell line Caco-2. Four clones (PD10, PF11, PD7 and TC7) from the heterogeneous parental Caco-2 cells population were used. After a screening step using isolated cells, the TC7 clone was selected for the study of alpha-linolenic acid uptake. [1-(14)C]linolenic acid dissolved in 10 mM taurocholate was presented to the microvillus plasma membrane (apical side) of TC7 differentiated cells, grown on a semi-permeable polycarbonate membrane. The results show that the initial rate of uptake is not a linear function of the 18:3(n- 3) monomer concentration in the incubation medium. In the monomer concentration range studied (0.2 to 36 microM) apical uptake was saturable and followed Michaelis-Menten kinetics (V(max) = 15.4 +/- 0.6 nmol/mg protein per min, K(m) = 14.3 +/- 1.3 microM). In addition, it was temperature- and energy-dependent but was apparently unaffected by the sodium gradient and intracellular metabolic fate of 18:3(n - 3). Excess of unlabeled saturated or unsaturated long chain fatty acids (C16 to C22) led to a 27-68% reduction of [1-(14)C]linolenic acid uptake. Likewise basolateral uptake was saturable (V(max) = 4.9 +/- 0.7 nmol/mg protein per min, K(m) = 8.7 +/- 2.9 microM). These facts argue in favour of the existence in these human intestinal cells of a carrier-mediated transport system for alpha-linolenic acid and probably other long chain fatty acids as well.

The lipidome as a composite biomarker of the modifiable part of the risk of breast cancer

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.

Efficiency of oxidative phosphorylation in liver mitochondria is decreased in a rat model of peritoneal carcinosis.

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<0.05; R(2)=0.64, p<0.05) and with a lower n-6/n-3 polyunsaturated fatty acid ratio in cardiolipin (-45%, p<0.05; R(2)=0.21, p<0.05) in PC rats. ROS production was increased by 12-fold in liver mitochondria from PC rats. CONCLUSIONS The efficiency of ATP synthesis was reduced and energy wasting processes were increased in liver mitochondria of PC rats. This suggests that liver mitochondria from PC rats request more nutrients than liver mitochondria from control rats to maintain the same ATP production. These alterations were associated to the content and fatty acid composition of cardiolipin.