Cytotoxic drugs efficacy correlates with adipose tissue docosahexaenoic acid level in locally advanced breast carcinoma

Experimental studies indicated that long-chain polyunsaturated fatty acids may increase sensitivity of mammary tumours to several cytotoxic drugs. To evaluate this hypothesis in breast cancer, we have prospectively studied the association between levels of fatty acids stored in breast adipose tissue and the response of the tumour to chemotherapy in 56 patients with an initially localized breast carcinoma. Adipose breast tissue was obtained at the time of biopsy, and individual fatty acids were measured as a percentage of total fatty acids using capillary gas chromatography. Patients then received primary chemotherapy, combining mitoxantrone, vindesine, cyclophosphamide and 5-fluorouracil every 4 weeks. Tumour size was reassessed after three cycles of chemotherapy. Tumour response was evaluated according to World Health Organization criteria. Complete or partial response to chemotherapy was achieved in 26 patients (47%). Level of n-3 polyunsaturated fatty acids in adipose tissue was higher in the group of patients with complete or partial response to chemotherapy than in patients with no response or with tumour progression (P < 0.004). Among n-3 polyunsaturated, only docosahexaenoic acid (22:6n-3) was significantly associated with tumour response (P < 0.005). In a logistic regression analysis taking into account age, body mass index and tumour size, 22:6 n-3 level proved to be an independent predictor for chemosensitivity (P = 0.03). These results suggest that, in breast cancer, 22:6 n-3 may increase the response of the tumour to the cytotoxic agents used. © 1999 Cancer Research Campaig

De novo Synthesis of Linoleic Acid in Multiple Collembola Species

Many ecological interactions in communities take place between consumers and the organisms they feed on. Continuous surplus of specific nutritional compounds in the diet may lead to evolutionary changes in the metabolic capacity of the consumer, leaving the biosynthesis of such compounds prone to genetic decay and render organisms auxotrophic. A nutrient that is essential to many organisms is the unsaturated fatty acid, linoleic acid (LA; 18:2n-6), which is important in the maintenance of cell membrane fluidity and as a precursor for signaling molecules. LA is readily synthesized in bacteria, protozoa and plants, but it was long thought that all animals lack this ability. Although the majority of animals lack the ability for LA biosynthesis, an increasing number of studies have shown that LA is commonly synthesized in arthropods. Here, we investigated a basal hexapod group, Collembola, to shed light on early evolution of LA synthetic ability in arthropods and its relation to dietary composition. We use stable isotope labeling to detect biosynthesis of LA in Collembola fed with C-13-OA oleic acid (OA; 18:1n-9), a precursor of LA. Our data demonstrate that LA biosynthesis is common among Collembola with 10 out of 16 tested species being able to synthesize LA and 4 species lacking this ability. However, we did not find clear evidence for a relationship between LA synthetic ability and the natural diet of species. Thus, the selective pressures underlying LA biosynthesis might be species-specific and further research will shed new light on understanding this evolutionary process